Evaluation of the Toronto Palatal Lift Prosthesis for Patients with Hypernasal Resonance Disorders.

Transcription

1 Evaluation of the Toronto Palatal Lift Prosthesis for Patients with Hypernasal Resonance Disorders. by Brett William Ayliffe A thesis submitted in conformity with the requirements for the degree of Masters of Science Graduate Department of Dentistry University of Toronto Copyright by Brett William Ayliffe 2013

2 ABSTRACT Evaluation of the Toronto Palatal Lift Prosthesis for Patients with Hypernasal Resonance Disorders. Brett William Ayliffe, DDS Masters of Science Graduate Department of Dentistry University of Toronto 2013 Statement of the problem. Hypernasality resulting from velopharyngeal insufficiency or incompetency is a resonance disorder that has negative consequences for speech production and intelligibility of afflicted individuals. Purpose. The purpose of this prospective study is to ascertain if a palatal lift prosthesis with a generic silicon velar lamina, termed the Toronto Palatal Lift Prosthesis (TPLP), can assist velopharyngeal valve function to reduce hypernasality in patients. Methods. A prospective study of six patients treated with the TPLP was compared by the outcome measures of nasalance scores, perceptual evaluations, and patient satisfaction to those obtained using a contemporary acrylic palatal lift prosthesis. Results. The six patients had varying degrees of reduction in hypernasality and acceptance of the TPLP. Conclusion. On the basis of this preliminary study on the TPLP it is possible to fabricate a palatal lift prosthesis with a generic silicon velar lamina that reduces hypernasality in select patients. ii

3 ACKNOWLEDGEMENTS I would like to thank my supervisor Dr. Tim Bressmann and Dr. Majd Al Mardini, the maxillofacial prosthodontist at the Princess Margaret Hospital, whom both made great contributions to the completion of this work. I would also like to acknowledge the following people for their assistance: Committee members: Dr. Asbjorn Jokstad and Dr. Hasan Alkumru. PMH Dental Department: Dr. Bob Wood and all the staff. Voice and Resonance Lab: Gillian de Boer and staff. Laboratory Assistance: Terri Jancen, Wanda Wagner, and LHM Dental Laboratory. Dr. Eszter Somogyi-Ganss for scientific input. I would also like to thank Nobel Biocare for the Research Fellowship in Prosthodontics iii

4 TABLE OF CONTENTS Abstract... ii Acknowledgements... iii Table of Contents... iv List of Tables... vii List of Figures...viii List of Appendices... xi 1. Introduction The Velopharyngeal Mechanism Velopharyngeal Dysfunction Velopharyngeal Insufficiency Velopharyngeal Incompetence Velopharyngeal Mislearning Prosthetic Treatment Review of Previous Work Historical Perspective- The Palatal Lift Prosthesis Modern Perspective- The Palatal Lift Prosthesis Chronological Review of Evaluation/Outcome Measures for Prosthetic Treatment of VPD Rationale Objectives Hypothesis Materials and Methods Setting Inclusion Criteria Exclusion Criteria Sample Size Patient Population iv

5 2.6 Potential Patient Risks or Complications Data Collection and Outcome Measures Nasometric Assessment Speech Acceptability Assessment Subjective Patient Feedback Questionnaire Statistical Analysis Fabrication of the TPLP Matrix Transfer Mold- Fabrication Velar Lamina- Fabrication Velar Lamina- Modification TPLP- Fabrication for Fully or Partially Dentate Patient TPLP- Fabrication for Fully Edentulous Patient Results Nasometric Assessment Results Speech Acceptability Assessment Results Subjective Patient Feedback Questionnaire Results Individual Patient Results Patient One Patient Two Patient Three Patient Four Patient Five Patient Six Discussion Velopharyngeal Insufficiency Patient Velopharyngeal Incompetency Patient Velar Lamina v

6 4.4 Potential Uses Conclusion References Appendices vi

7 LIST OF TABLES TABLE 1 CHRONOLOGICAL REVIEW OF EVALUATION/OUTCOME MEASURES FOR PROSTHETIC TREATMENT OF VPD TABLE 2 PATIENT DEMOGRAPHIC INFORMATION TABLE 3 MEAN NASALANCE VALUE(%): ZOO PASSAGE WITHOUT NASAL CONSONANTS. PATIENT 1 TPLP DATA LOST DURING DATA TRANSFER TABLE 4 WILCOXON SIGNED RANKS TEST STATISTICS FOR THE ZOO PASSAGE TABLE 5 MEAN NASALANCE VALUE(%): NASAL SENTENCES WITH NASAL CONSONANTS TABLE 6 WILCOXON SIGNED RANKS TEST STATISTICS FOR THE NASAL SENTENCES TABLE 7 COMPARISON OF SPEECH ACCEPTABILITY RESULTS: PATIENT TABLE 8 WILCOXON SIGNED RANKS TEST STATISTICS OF SPEECH ACCEPTABILITY RESULTS TABLE 9 PATIENT QUESTIONNAIRE: QUESTION 1 RESULTS TABLE 10 PATIENT QUESTIONNAIRE: QUESTION 2 RESULTS TABLE 11 PATIENT QUESTIONNAIRE: QUESTION 3 RESULTS TABLE 12 PATIENT QUESTIONNAIRE: QUESTION 4 RESULTS TABLE 13 COMPARISON OF AVERAGES OBTAINED FROM THE PATIENT QUESTIONNAIRE vii

8 LIST OF FIGURES FIGURE 1 ILLUSTRATION OF THE MAJOR MUSCLES OF THE VELOPHARYNGEAL MECHANISM IN AN INDIVIDUAL WITH NORMAL ANATOMY FROM THE PERSPECTIVE OF THE PHARYNX BEING SPREAD OPEN FROM THE POSTERIOR.[4]... 2 FIGURE 2 ILLUSTRATION OF LEAVES DEPICTING OUTLINE FORMS FROM LEFT TO RIGHT: OVATE, OBOVATE AND PANDURATE.[7] COPYRIGHT 1983, ELSEVIER FIGURE 3 ILLUSTRATION OF DELABARRE'S OBTURATOR, MACHINE, WITH VELUM AND UVULA MADE OF ELASTIC GUM.[12] FIGURE 4 ILLUSTRATION OF THE PROSTHESIS, ARTIFICIAL VELUM, FABRICATED BY SERCOMBE IN 1857.[12] FIGURE 5 ILLUSTRATION OF THE PROSTHESIS, ARTIFICIAL PALATE, FABRICATED BY KINGSLEY IN A AND B- WINGS MADE FROM SOFT RUBBER TO REPRODUCE THE SOFT PALATE. C- MAXILLARY DENTURE BASE.[13] FIGURE 6 (LEFT) ILLUSTRATION OF THE SOFT RUBBER WINGS (A,D) OF THE KINGSLEY PROSTHESIS IN RELATION TO THE RESIDUAL SOFT PALATE. (MIDDLE AND RIGHT) UNIVERSAL ARTIFICIAL SOFT RUBBER WINGS, THE SMALLEST AND LARGEST SETS HE EVER PRODUCED ILLUSTRATED.[12] FIGURE 7 AN EXAMPLE OF SUERSEN'S SPEECH PROSTHESIS THAT RESEMBLES A CONTEMPORARY SPEECH PROSTHESIS.[12] FIGURE 8 PROSTHESES FABRICATED BY GIBBONS. (LEFT) FIXED BULB OBTURATOR. (MIDDLE) INTERIM PROSTHESIS. (RIGHT) DEFINITIVE PROSTHESIS.[8] COPYRIGHT 1958, ELSEVIER. 20 FIGURE 9 PALATAL ELEVATOR BUTTON FABRICATED BY BEDER IN THIS PROSTHESIS USED A GENERIC VELAR LAMINA.[15] COPYRIGHT 1968, ELSEVIER FIGURE 10 (ABOVE) PALATAL LIFT PROSTHESIS. (A) PRIOR TO SOFT PALATE STIMULATION BY A PALATAL LIFT PROSTHESIS. (B) ELEVATED SOFT PALATE WITH THE PALATAL LIFT PROSTHESIS IN PLACE. (BELOW) COMBINATION LIFT BULB PROSTHESIS. (A) SHORT SOFT PALATE AND LARGE NASOPHARYNX. (B) COMBINED LIFT BULB PROSTHESIS IN PLACE.[6] COPYRIGHT 1976, ELSEVIER FIGURE 11 (LEFT) PALATAL LIFT PROSTHESIS THAT ELEVATES THE PATIENT S SOFT PALATE ALONG THE MIDLINE SUPERIORLY. (RIGHT) PALATAL LIFT PROSTHESIS WITH A NARROW PALATAL PROJECTION TO BYPASS TAUT ANTERIOR FAUCIAL PILLARS (PALATOGLOSSUS MUSCLES) AND WITH EXTENSIVE POSTERIOR LATERAL PROJECTIONS TO LIFT THE SOFT PALATE INTO THE LATERAL VELOPHARYNGEAL PORT AREAS.[18] COPYRIGHT 1979, ELSEVIER viii

9 FIGURE 12 PALATAL LIFT PROSTHESIS FOR A FULLY EDENTULOUS PATIENT WITH NICKEL- TITANIUM WIRES JOINING THE VELAR LAMINA TO THE COMPLETE DENTURE.[19] COPYRIGHT 1987, ELSEVIER FIGURE 13 PALATAL LIFT PROSTHESIS FABRICATED WITH A THERMO-SOFTENED VINYL VELAR LAMINA.[20] COPYRIGHT 1988, JOHN WILEY & SONS, INC FIGURE 14 (LEFT) FIRST VELAR LAMINA PROTOTYPE WITH AN OBOVATE OUTLINE FORM. (RIGHT) SECOND VELAR LAMINA PROTOTYPE WITH A TRUNCATE OVATE OUTLINE FORM FIGURE 15 (LEFT) MATRIX TRANSFER MOLDING PROCESS- ONE HALF OF MOLD WITH VELAR LAMINA WIRE POSITIONER AND VELAR LAMINA. (RIGHT) MATRIX TRANSFER MOLD PRESSED IN DENTURE FLASK PRESS AT 1000 PSI FIGURE 16 (TOP) TRUNCATE OVATE VELAR LAMINA AFTER REMOVAL FROM MATRIX TRANSFER MOLD. (BOTTOM) OBOVATE VELAR LAMINA AFTER TRIMMING FIGURE 17 IMPRESSION REQUIRED TO FABRICATE CONVENTIONAL PROSTHESIS. TPLP REQUIRES IMPRESSION LIMITED TO HARD PALATE REGION FIGURE 18 (FAR LEFT) COLD CURE ACRYLIC DUPLICATE MAXILLARY DENTURE BASE REMOVED FROM MOLD. (LEFT) TRIMMED DUPLICATE MAXILLARY DENTURE BASE PREPARED FOR RETENTION TUBES. (RIGHT) RETENTION TUBES IMBEDDED IN COLD CURE ACRYLIC. (FAR RIGHT) DUPLICATE MAXILLARY DENTURE BASE WITH DENTURE TEETH ADDED IN WAX AND VELAR LAMINA ADDED FOR TRY-IN WITH PATIENT PRIOR TO FINAL PROCESSING FIGURE 19 (LEFT) TROUGH CUT INTO MAXILLARY DENTURE BASE. (MIDDLE) ORTHODONTIC TUBES OCCLUDED WITH WAX AT EACH END TACKED TO MAXILLARY DENTURE BASE WITH CYANOACRYLATE. (RIGHT) COLD CURE ACRYLIC RESIN ADDED TO TROUGH VIA SALT AND PEPPER TECHNIQUE FIGURE 20 PATIENT 1: (LEFT) CONVENTIONAL PROSTHESIS. (MIDDLE) TPLP MADE WITH ACRYLIC MAXILLARY DENTURE BASE. (RIGHT) TPLP MADE WITH CAST FRAMEWORK MAXILLARY DENTURE BASE FIGURE 21 PATIENT 1: (LEFT) TPLP ACRYLIC MAXILLARY DENTURE BASE. (RIGHT) TPLP CAST MAXILLARY DENTURE BASE FIGURE 22 PATIENT 2: (TOP LEFT) EXISTING SOFT PALATE DEFECT. (TOP RIGHT) EXISTING CONVENTIONAL PROSTHESIS INSERTED. (BOTTOM) PROFILE OF EXISTING CONVENTIONAL PROSTHESIS FIGURE 23 PATIENT 2: (LEFT) TRY-IN OF DUPLICATED MAXILLARY DENTURE BASE. (MIDDLE) TRY-IN OF PROCESSED MAXILLARY DENTURE BASE. (RIGHT) TRY-IN OF PROCESSED MAXILLARY DENTURE BASE WITH VELAR LAMINA ATTACHED. NOTICE DISLODGEMENT OF THE ANTERIOR OF THE PROSTHESIS VENTRALLY FIGURE 24 PATIENT 3: (FAR LEFT) EXISTING SOFT PALATE DEFECT. (LEFT) EXISTING CONVENTIONAL PROSTHESIS INSERTED. (RIGHT) TPLP WITH VELAR LAMINA OF LESSER ix

10 DUROMETER INSERTED. (FAR RIGHT) TPLP WITH VELAR LAMINA OF HIGHER DUROMETER INSERTED FIGURE 25 TRUNCATE OVATE VELAR LAMINA OUTLINE FORM IN LESSER DUROMETER SILICON FIGURE 26 PATIENT 4: (LEFT) CONVENTIONAL PROSTHESIS. (RIGHT) TPLP FIGURE 27 PATIENT 4: (LEFT) EXISTING SOFT PALATE DEFECT. (RIGHT) TPLP WITH VELAR LAMINA OF LESSER DUROMETER INSERTED FIGURE 28 PATIENT 5: (FAR LEFT) EXISTING CONVENTIONAL PROSTHESIS. (LEFT) NEW CONVENTIONAL PROSTHESIS WITH PARTIAL VELAR LAMINA. (RIGHT) NEW CONVENTIONAL PROSTHESIS WITH COMPLETE VELAR LAMINA. (FAR RIGHT) TPLP FIGURE 29 PATIENT 5: (UPPER) VELAR LAMINA OF CONVENTIONAL PROSTHESIS MODIFIED TO MORPHOLOGY OF PREVIOUS PROSTHESIS BY SALT-AND-PEPPER ADDITION OF COLD CURE ACRYLIC. (MIDDLE) PROFILE OF VELAR LAMINA OF PREVIOUS PROSTHESIS. (BOTTOM) PROFILE OF VELAR LAMINA OF NEW PROSTHESIS FIGURE 30 PATIENT 6: (LEFT) EXISTING SOFT PALATE ANATOMY. (MIDDLE) EXISTING CONVENTIONAL PROSTHESIS INSERTED. (RIGHT) TPLP WITH VELAR LAMINA OF GREATER DUROMETER INSERTED FIGURE 31 PATIENT 6: (LEFT) CONVENTIONAL PROSTHESIS. (RIGHT) TPLP x

11 LIST OF APPENDICES APPENDIX 1: TREATMENT MODALITY SELECTION BY WOLFAARDT.[21] COPYRIGHT 1993, ELSEVIER APPENDIX 2: NOTIFICATION OF REB INITIAL APPROVAL APPENDIX 3: CARING FOR YOUR TORONTO PALATAL LIFT PROSTHESIS APPENDIX 4: TEXT PASSAGES TO BE USED FOR THE NASALANCE RECORDINGS APPENDIX 5: PATIENT QUESTIONNAIRE xi

12 1. INTRODUCTION 1.1 THE VELOPHARYNGEAL MECHANISM The velopharyngeal mechanism consists of a muscular valve, or sphincter, that extends from the posterior surface of the hard palate, the vibrating line, to the posterior pharyngeal wall.[1] In order to function, the mechanism requires the contributions of the soft palate (velum), lateral pharyngeal walls, and the posterior pharyngeal wall. The velopharyngeal mechanism is formed by the posterior and superior movement of the middle third of the soft palate, the anterior movement of the posterior pharyngeal wall, and the medial movement of the lateral pharyngeal walls.[2] The orifice or gap behind the soft palate is called the velopharyngeal port and it is this distance that the soft palate and pharyngeal walls must overcome to have complete closure during speech and swallowing.[1] The function of the velopharyngeal mechanism is to regulate separation between the oropharynx and the nasopharynx during swallowing and it also functions to proportion the air stream between the oral and nasal cavities which influences voice quality.[2, 3] During speech, normal complete velopharyngeal closure is necessary to be able to produce oral speech phonemes but there are three sounds in the English language, /m/, /n/, /ng/, that are produced with an open velopharyngeal port.[1] If the velopharyngeal mechanism is to function properly then the associated muscles must be 1

13 2 fully operational. The muscles responsible for function of the velopharyngeal mechanism, Figure 1[4], include the levator veli palatini, musculus uvulae, tensor veli palatini, superior pharyngeal constrictor, palatopharyngeus, palatoglossus, and salpingopharyngeus. The paired levator veli palatini muscle inserts into the middle of the soft palate and is the most important muscle for normal velopharyngeal closure. Figure 1 Illustration of the major muscles of the velopharyngeal mechanism in an individual with normal anatomy from the perspective of the pharynx being spread open from the posterior.[4] The muscle enters the soft palate and fans outward within the soft palate with each muscle eventually joining the opposing levator veli palatini muscle bundles. From its'

14 3 origin at the base of the skull the paired levator veli palatini muscles form a sling that functions to retract and elevate the soft palate as it does in speech when it pulls the soft palate up to a 45 angle to close against the posterior pharyngeal wall. The musculus uvulae is fully contained within the body of the soft palate. The function of the musculus uvulae is to assist in filling the gap between the soft palate and the posterior pharyngeal wall which aids in producing a tighter seal during velopharyngeal closure. The tight seal is possible due to the muscular bulk it adds to the nasal surface of the soft palate as well as the convex geometry it produces at the knee (also called bend or eminence) of the soft palate. The tensor veli palatini opens the eustachian tube during swallowing and yawning. The superior pharyngeal constrictor is in the region of the velopharynx and has fibers that attach directly to the soft palate that may assist with retraction of the soft palate. The horizontal fibers of the superior pharyngeal constrictor may be contributory in the formation of a Passavant's ridge when it is present. The palatopharyngeus muscle has vertical and transverse fibers referred to as palatothyroideus and palatopharyngeus proper, respectively. The vertical fibers assist in the overall position of the soft palate. The transverse fibers travel from the posterior of the soft palate to terminate along the lateral pharyngeal walls and are said to contribute to the inward displacement of the lateral pharyngeal walls and may be contributory in the formation of Passavant's ridge. The palatoglossus muscle travels from the lateral margins of the soft palate, through the anterior faucial pillars, and inserts onto the lateral aspect of the tongue. The palatoglossus muscle is the antagonist of the levator veli palatini muscle and can function to lower the soft palate, elevate the posterior tongue or constrict the faucial isthmus. The coordination of the

15 4 contraction of the palatopharyngeus and palatoglossus muscles with soft palate elevation by the levator veli palatini muscle result in the positioning of the soft palate. The salpingopharyngeus muscle travels along and terminates in the lateral pharyngeal walls and may be a minor contributor in providing a superior pull on the lateral pharyngeal walls.[1] 1.2 VELOPHARYNGEAL DYSFUNCTION Velopharyngeal dysfunction (VPD) is a broad term that includes all disorders that involve inconsistent and incomplete closure of the velopharyngeal valve during the production of oral sounds or swallowing. Incomplete velopharyngeal valve closure results in the escape of air into the nasal cavity which can cause nasal air emission and/or hypernasal speech. Velopharyngeal dysfunction may occur due to velopharyngeal insufficiency, velopharyngeal incompetence or due to velopharyngeal mislearning.[5] Speech characteristics common to velopharyngeal insufficiency and incompetence are hypernasality, nasal air emission and decreased intelligibility of speech due to weak consonant production.[6] VELOPHARYNGEAL INSUFFICIENCY Velopharyngeal insufficiency (VPI) is an acquired or congenital anatomic or structural defect that prevents appropriate closure of the velopharyngeal valve. Velopharyngeal insufficiency may be a result of a cleft palate or submucous cleft palate, deep pharynx,

16 5 irregular or atrophied adenoids, adenoidectomy, hypertrophic tonsils, tonsillectomy, maxillary advancement surgery, or the anatomical condition following treatment of oral cavity tumors. Cleft palate is a major cause of velopharyngeal insufficiency. It is observed in approximately 20 to 30% of cleft patients following surgical repair.[5] A submucous cleft palate is a deficiency beneath the oral mucosa of the soft palate that may involve the muscles of the soft palate and the bone of the hard palate. Therefore, the greater the extension of the submucous defect, the greater the impact on velopharyngeal function. A deep pharynx may cause velopharyngeal insufficiency due to the posteriorly deep position of the pharyngeal wall that consequently limits complete velopharyngeal closure. Adenoids are present in children and may play a role in velopharyngeal closure due to their anatomical relationship with the velopharynx. Due to the prominence of the adenoids, children tend to have veloadenoidal closure but after approximately age six the adenoids naturally shrink with further atrophy experienced at puberty. An individual with an abnormal soft palate may experience reduced velopharyngeal closure as the adenoids atrophy. Children with irregular adenoids may experience velopharyngeal insufficiency due to the inability of the indented or protruded adenoid tissue to afford a tight velopharyngeal seal. If the adenoids are completely removed (adenoidectomy) then a deeper nasopharynx results and the soft palate may not be physically long enough to achieve velopharyngeal closure. Typically patients adapt to this situation within 6 weeks but approximately 1 in 1500 adenoidectomy procedures results in permanent velopharyngeal insufficiency. Hypertrophic tonsils may affect velopharyngeal closure when they are large enough to extend into the pharynx and cause mechanical interference with the velopharyngeal

17 6 valve. Their encroachment into the pharyngeal space prevents the lateral pharyngeal walls from moving medially and producing an appropriate seal. If the tonsils are removed (tonsillectomy), rarely does velopharyngeal insufficiency develop. However, if excessive scar tissue or keloids develop post-operatively then lateral pharyngeal wall movement may be reduced thus potentially decreasing the velopharyngeal seal. Some patients may develop an alteration in velopharyngeal closure due to post-operative pain resulting in a conversion disorder following tonsillectomy. A maxillary advancement surgically increases the distance between the maxilla and the posterior pharyngeal wall and subsequently increases the pharyngeal depth. Tumors of the oral cavity may require resection or radiation treatment modalities. Areas of resection may directly compromise the anatomical division between the oral and nasal cavities and the ability to produce a velopharyngeal seal. Radiation of tissues causes tissue shrinkage and damage that may limit velopharyngeal closure and also limit surgical intervention due to decreased tissue healing potential. Velopharyngeal insufficiency may be treated surgically, prosthetically, with speech therapy, or by a combination of the aforementioned modalities.[5] VELOPHARYNGEAL INCOMPETENCE Velopharyngeal incompetence (VPI) exists when a patient with adequate anatomy suffers from a neurophysiological deficiency that causes inadequate movement of the structures comprising the velopharyngeal valve. In this situation, the level of the soft palate is typically insufficiently elevated with a resultant inadequate "knee action" of the

18 7 soft palate during speech. Velopharyngeal incompetence may be a result of muscular hypotonia, neurological conditions causing dysarthria or apraxia, or cranial nerve defects. If a patient suffers from generalized hypotonia then decreased movement of all the components of the velopharyngeal valve may be affected. Dysarthria is a motor speech disorder that affects all the subsystems of speech, including velopharyngeal function, and results in characteristically hypernasal speech. Examples of neurological conditions that exhibit dysarthria are: cerebral palsy, myotonic dystrophy, myasthenia gravis, neurofibromatosis, cerebral or brainstem tumors, developmental delay, traumatic brain injury, cerebral vascular accident and other causes of cortical and subcortical damage. Apraxia of speech is an oral-motor disorder that is characterized by difficulty executing and sequencing speech movements. All of the components of speech articulation are affected including the lips, tongue, mandible and velopharyngeal valve. The individual exhibits improper coordination of the articulators and thus a mixed hypernasal and hyponasal speech results. Cranial nerve defects that involve the glossopharyngeal nerve (IX), the vagus nerve (X), or the hypoglossal nerve (XII) can result in paralysis or paresis of the soft palate or pharyngeal musculature. Defects are typically unilateral and the resultant motor damage can cause insufficient velopharyngeal closure of the affected region. Velopharyngeal incompetency may be treated surgically, prosthetically, with speech therapy, or by a combination of the aforementioned modalities.[5]

19 VELOPHARYNGEAL MISLEARNING Velopharyngeal mislearning may develop in a patient due to faulty articulation, compensatory speech productions or due to a lack of auditory feedback. Faulty articulation occurs when an individual learns to produce a speech sound incorrectly and therefore develops a speech sound disorder. When a speech sound is produced incorrectly with an open velopharyngeal valve, nasal air emission results. Nasal air emission can even be phoneme-specific. An individual with this resonance disorder can undergo speech therapy to correct the faulty articulation. If a patient experiences significant VPI during speech development, the patient may compensate for the lack of intraoral pressure by producing sounds in the pharynx or at the level of the glottis. If the VPI is corrected, the compensatory articulations may persist due to the learned behaviour, and hypernasality and nasal emission will remain. This patient will require speech therapy to eliminate the compensatory articulations and permit normal speech production. Finally, a patient who is deaf or has severe hearing loss may not be able to monitor the resonance of his or her voice and exhibit abnormal resonance. The velopharyngeal valve may therefore function inappropriately causing hypernasality, hyponasality or a mixed resonance. All forms of velopharyngeal mislearning are corrected through speech language therapy to modify inappropriate articulations of speech.[5]

20 9 1.3 PROSTHETIC TREATMENT One treatment modality to address VPD is prosthetic intervention by fabrication of a palatal lift prosthesis. A palatal lift prosthesis can be reduced to an anterior and a posterior segment; termed maxillary denture base and velar lamina, respectively[7]. A conventional prosthesis is fabricated with both segments being unique to the individual. The maxillary denture base is primarily responsible for retention of the prosthesis while the function of the velar lamina is to separate the oropharynx and nasopharynx to reduce hypernasality. Over time, as the prosthesis is utilized the maxillary denture base is essentially only modified as the dentulous state or alveolar anatomy of the individual changes. However, the velar lamina is situated in a dynamic region and may require more alteration as the individual experiences soft tissue changes related to the presence of the velar lamina, any increase in soft tissue muscle tone, and any adaptation as a consequence of speech therapy. If a prosthesis was modular and a functional generic velar lamina was producible then the prosthodontist or potentially the speech pathologist could interchange and experiment with different velar lamina outline forms. Several outline forms have been defined for velar lamina for a conventional palatal lift prosthesis and are described as follows: ovate, obovate or inversely ovate, and pandurate or panduriform, Figure 2.[7] A generic velar lamina should be designed to permit marginal adaptation to the outline forms previously described. With a conventional prosthesis, any modifications to be made to the prosthesis are performed by a prosthodontist in a dental office environment with the resultant final prosthesis being a unique object that is often guarded by the patient. A more generic and modular

21 10 Figure 2 Illustration of leaves depicting outline forms from left to right: ovate, obovate and pandurate.[7] Copyright 1983, Elsevier. prosthesis may permit easier prosthesis fabrication, easier prosthesis replacement, and an increase to access to care by more members of the treatment team. The primary aim of this study is to compare a palatal lift prosthesis with a generic flexible velar lamina fabricated from silicon to the conventional palatal lift prosthesis that incorporates a rigid velar lamina fabricated from acrylic resin.[7] The palatal lift prosthesis will be used to remediate hypernasality in patients with head and neck cancer, neurogenic speech disorders, and could be utilized where hypernasality exists in patients with cleft lip and palate. Evaluation of the prosthesis will be determined by the outcome measures of nasalance scores, perceptual evaluations, and patient satisfaction. This study also wishes to determine if it is possible to produce a functional

22 11 palatal lift prosthesis that is generic in nature. Contemporary examples of speech prostheses have been made for over 50 years and have followed a very similar process of construction with comparable materials since they were first introduced.[8] As is customary with removable prosthodontics methodology, the accuracy of the impressions made are critical to the success of the final prosthesis. It has been stated that the pharyngeal extension needs to conform to the dimension, shape and position of the velopharyngeal opening which exists during function.[9] However, the taking of an impression of the soft palate and velopharyngeal region can be an unpleasant procedure for the patient. We wish to investigate if it is possible to produce a palatal lift prosthesis to combat hypernasality that is produced from a much simpler attained maxillary impression that is limited to the hard palate region. There are previous examples of speech prostheses that have been produced from maxillary impressions of the hard palate region but we also wish to also make the prosthesis more "user friendly" by making it a more modular and adaptable object. A modular and adaptable prosthesis may permit an increase in speech prosthesis exposure and usage by patients since at present it is not a customary procedure for a speech pathologist to alter or experiment with a prosthesis while with a patient during a treatment session. If producible, a modular prosthesis with a generic velar lamina may permit increased interaction between the patient and the speech pathologist which could in turn benefit the patient during speech therapy.

23 REVIEW OF PREVIOUS W ORK Upon searching the literature on the origin and evolution of the palatal lift prosthesis it is soon apparent that the origination of the palatal lift prosthesis is commonly attributed to Gibbons and Bloomer due to their work from They most definitely fabricated a palatal lift prosthesis that clearly resembles a contemporary prosthesis. However, the origin of a prosthesis that lifts the soft palate to aid in speech, mastication and deglutition can be traced far further back in history HISTORICAL PERSPECTIVE- THE PALATAL LIFT PROSTHESIS Delabarre was an innovator in the field of mechanical dentistry and in 1820 one such contribution was the fabrication of a complicated prosthesis that completely covered the hard palate. The prosthesis (Figure 3) was carved out of metal with a depression in the Figure 3 Illustration of Delabarre's obturator, machine, with velum and uvula made of elastic gum.[12]

24 13 superior surface to accommodate the nasal palatine process. Mineral teeth were attached to the prosthesis by means of springs and a moveable part to restore the velum and uvula was made from elastic gum. Therefore, he may be considered the first one to use a soft, flexible elastic valve to imitate the function of the soft palate. In the same prosthesis he attached a valve to the superior surface, which was activated by movement of the tongue to separate the nasal cavity from the oral cavity during deglutition.[10] The prosthesis was fabricated for an edentulous individual who had difficulty with deglutition and was described as hypernasal due to this loss of a considerable portion of his hard and soft palate as a consequence of syphilis. Delabarre describes his prosthesis, termed machine, as follows: "The machine subserved a part of the object; that is to say, the nose and the mouth were separated by it; the patient however still spoke through his nose, because the soft portion of the palate was wanting. It was then necessary to replace this. I could have constructed a cover and a moveable plate in metal, as the goldsmith Cadot, of whom Cullerier speaks, has done. But I preferred gum elastic. I wished to employ the mechanism of deglutition for my purposes, which were that the artificial cover should raise and fall every time the passage of food, and even that of saliva, should be effected from the mouth into the pharynx. Consequently the tongue became the means of putting the mechanism in motion, and this latter was disposed of to this effect, in the following manner. I made an oval window in the fore part of the palate; I then placed a valve which clasped itself hermetrically and which was held in place by means of an axis and a small very soft spring. To this plate was soldered a lever which passing backward, rested on another which was held in a see-saw position by an axis. This last lever was enough to reach the extremity of the principal plate, and it was flattened, so as to fasten to the movable vellum, which itself was attached to the pharyngeal border of the instrument. During deglutition, the point of the tongue, applying itself, pressed upon the valve, which transmitted to all the other parts the movement impressed upon it. Thus the velum raised, and from a vertical, assumed nearly a horizontal position; in such a way that neither solid food nor drinks could escape into the nasal cavities. This plate, complicated with the artificial teeth, was yet by no means heavy, for the plates were of very thin platina, soldered with fine gold. The patient derived great advantage from it, both in mastication and deglutition, and in the articulation of words."[11] The prosthesis Delabarre describes is mechanically complicated but it functions to extend and raise the soft palate to enhance mastication, deglutition and speech and may very well be the origin of the palatal lift prosthesis.

25 14 In 1841 Stern, a medical doctor with a congenital cleft, became acquainted with enhancements made in the fabrication of rubber by Goodyear. Since he had undergone a few unsuccessful operations to close his own soft palate he fabricated his own prosthesis. He had a medical background and therefore limited knowledge of prosthetic dentistry and subsequently he used carved wood to make the molds for vulcanizing the rubber velum of his prosthesis.[10] Stern stated that in order to have success in producing an artificial velum for a congenital cleft, the portion of the prosthesis filling the fissure in the natural palate must be made of a material with characteristics similar to the natural palate. With similar characteristics the artificial velum could then be elevated by the surrounding levator veli palatini muscles. The elevated artificial velum could then shut off the nasal passage which was necessary since it was absolutely essential in the production of certain sounds.[12] His prosthesis demonstrated that a velar lamina made of rubber could be introduced into the pharynx, worn with comfort and that it could assist in the articulation of speech.[10] In 1857, Sercombe produced a prosthesis, termed artificial velum, with a velar lamina made from two pieces of vulcanized India-rubber; a larger extremely thin piece and a smaller thicker piece as shown in Figure 4.[12] The maxillary denture base was a framework cast in gold that included a posterior extension with holes punched along the perimeter that was used to unite the vulcanized India-rubber pieces to the framework. The vulcanized India-rubber pieces were cut out of prefabricated sheets and were positioned to sandwich the posterior extension of the gold framework. The

26 15 India-rubber pieces were attached to the posterior extension by sewing them together, with silk, fine platina, gold or silver wire, through the holes punched along the perimeter Figure 4 Illustration of the prosthesis, artificial velum, fabricated by Sercombe in 1857.[12] of the metal, indicated by the dashed line in Figure 4. The smaller vulcanized Indiarubber piece was a standard shape and ventral to the larger piece that was cut to a unique outline contour for each patient. The morphology of the larger piece was determined so that the free convex margin did not touch the back of the pharynx during deglutition since an ulcer would develop even with the soft material. However, the larger piece had to be close to the back of the pharynx or the patients' articulation would have a characteristic nasal sound. Sercombe stated that "the large piece should also be extremely thin as it is absolutely necessary that it should adapt itself with great readiness and completeness to the ever-varying sides of the fissure; but a piece of such tenuity as is necessary to secure this vital point, weighted with mucus, would quickly droop, but for the support which is given to it by the smaller and stouter piece which lies immediately underneath it." The velar lamina designed by Sercombe is of a

27 16 similar design to that of the TPLP. Sercombe stated that in more than one instance his prosthesis was able to restore a person to intelligible speech. However, in its day, the prosthesis was criticized for having a flawed design and therefore it would be impossible for a person with a congenital cleft to achieve better speech[12] Sercombe's prosthesis was further criticized because it was made of common sheet rubber used for purposes other than dentistry and potentially not pure enough for oral use. Since Sercombe used common sheet rubber of uniform thickness he did not require an impression of the soft palate to make a mold for fabrication of the prosthesis and was indeed producing a relatively generic velar lamina.[13] In 1860, Kingsley described his prosthesis, an artificial palate, that took advantage of the remaining muscular movement of the soft palate of a patient with a soft palate defect.[13] The prosthesis (Figure 5) was made for an edentulous patient and was Figure 5 Illustration of the prosthesis, artificial palate, fabricated by Kingsley in A and B- Wings made from soft rubber to reproduce the soft palate. C- Maxillary denture base.[13]

28 17 comprised of a complete maxillary denture base that supported an artificial soft palate. The patient wanted a duplicate prosthesis so Kingsley made two maxillary denture bases, plates, one of gold and the other of platinum. The plates had a groove along the median at the posterior to attach the artificial palate. The artificial palate was produced from two wings made from soft rubber to simulate the characteristics of the natural soft palate. The wings were attached to a gold frame and a joint was provided to permit the artificial palate to raise and lower during function. The inferior wing bridged the oral cavity surface of the defect while the superior wing bridged the nasal cavity surface of the defect and was positioned posteriorly until it nearly touched the muscles of the pharynx at rest. Both wings extended beyond the openings they occluded by about ⅛ to ¼ of an inch which permitted the wings to sandwich the residual soft palate and be carried up or down by the movement of the residual soft Figure 6 (left) Illustration of the soft rubber wings (A,D) of the Kingsley prosthesis in relation to the residual soft palate. (middle and right) Universal artificial soft rubber wings, the smallest and largest sets he ever produced illustrated.[12] palate as required The prosthesis was made for a patient who had gone without a prosthesis for seven years and it converted her very defective articulation into

29 18 intelligible speech within one month.[13] Kingsley thought, after having hundreds of these prostheses in use, that his prosthesis design could be universally adapted to almost any case requiring an artificial soft palate. Since each prosthesis involved agreat deal of labor by the dentist, he used a series of molds of different wing sizes from which nearly every case of congenital cleft could be restored (Figure 6). In his practice, he had amassed a collection of a hundred molds from which he could select the appropriate sizes of the soft rubber wings to be used for fabrication of the velar lamina. Kingsley labeled this prosthesis as a universal artificial palate and he did consider it feasible that such a prosthesis could be fabricated in a generic manner.[12] In 1867 Suersen, introduced the basic principles in speech prosthesis design that are seen in a contemporary speech prosthesis. It is quite remarkable how similar Figure 7 An example of Suersen's speech prosthesis that resembles a contemporary speech prosthesis.[12] Suersen's prosthesis, Figure 7, resembles a typical speech bulb fabricated today.[10] Suersen stated that in order to be able to properly pronounce all speech distinctly, it

30 19 was necessary to separate the nasal and oral cavities by use of the actions of the muscles involved. However, he based his prosthesis on the function of the superior pharyngeal constrictor muscle and not the levator veli palatini muscle that was used by prostheses of the era. His prosthesis was made of hard caoutchouc and was comprised of a maxillary denture based that clasped to existing teeth and covered any defect of the hard palate but transitioned at the soft palate with an apophasis the width of the defect at that point. The prosthesis extended into the defect in the soft palate to a thickness that permitted the defect margins of the soft palate to keep in contact with the prosthesis during rest and function. The prosthesis permitted patency of the nasal airway when the soft palate was at rest and occluded the nasal and oral cavities during function.[12] MODERN PERSPECTIVE- THE PALATAL LIFT PROSTHESIS In 1958, a design for a supportive prosthetic speech aid was described by Gibbons and Bloomer which is equivalent to a contemporary speech prosthesis fabricated for velopharyngeal incompetence.[8] The prosthesis was fabricated for a patient with poor speech intelligibility and hypernasality due to inadequate pharyngeal movement. The function of the prosthesis was to provide palatal elevation to decrease the lumen of the palatopharyngeal valve during speech. As is typical today an interim prosthesis was produced that was eventually replaced with a definitive prosthesis, commonly having increased retention. The first speech aid constructed, Figure 8 (left), resembled a fixed

31 20 bulb-type obturator that was used by cleft palate patients of that era. The patient was not able to tolerate the device. The second speech aid, Figure 8 (middle), displaced Figure 8 Prostheses fabricated by Gibbons. (left) Fixed bulb obturator. (middle) Interim prosthesis. (right) Definitive prosthesis.[8] Copyright 1958, Elsevier. the soft palate in an upward direction to permit the soft palate to attain a position as it would during normal function. It was postulated that an elevation of the soft palate to a position of almost closure might possibly permit the restoration of enough muscular function of the palatopharyngeal valve to effect a complete closure. The speech aid was constructed of acrylic providing full coverage of the hard palate with wrought wire clasps on the bilateral maxillary first premolars and first molars. The soft palate was elevated by a broad convex acrylic velar lamina that extended directly from the maxillary denture base covering the hard palate. Since an insufficient return of muscle function resulted after using the second prosthesis the construction of a more permanent prosthesis, (Figure 8, right), was completed. The definitive prosthesis utilized a cast metal framework with wrought wire retainers on the bilateral maxillary first premolars and first molars as the maxillary denture base to which an acrylic velar lamina was attached. The prosthesis provided a great improvement in distinctness of consonant articulation and a considerable reduction in hypernasality. The change in hypernasality was described as going from a "cleft palate" type hypernasality to a

32 21 hypernasality resembling a "normal" speaker with a slightly relaxed palatopharyngeal valve. The authors concluded that their speech prosthesis provided: 1. A reduction in the palatopharyngeal lumen that affords a decrease in hypernasality and subsequent increase in oral pressure for consonant articulation. 2. The preservation of an airway to provide for comfortable nasal breathing. 3. The avoidance of undue stress upon the supporting teeth as the prosthesis resists the natural elasticity and weight of the palate in elevation. 4. The absence of injury to the soft palate as a result of pressure from the supporting portion of the palatal section. This work is commonly cited as the origination of the palatal lift prosthesis by contemporary authors. [8] In the years following the work by Gibbons and Bloomer, several different palatal lift prosthesis designs were introduced and tested. In essence, the function of the prosthesis is the same today as it was in the 1800's or the 1950's, to elevate the soft palate effectively to permit a reduction in hypernasality and produce intelligible speech. Therefore, authors attempted, with varied results, novel variations of the standard Gibbons and Bloomer prosthesis to try and enhance the palatal lift prosthesis. Several modifications to the basic prosthesis were tried, such as adding a hinge to unite the maxillary denture base with the velar lamina. In fact, the majority of these novel ideas had already been attempted during the nineteenth century with earlier materials. Nevertheless, it is worth discuissing some of the modifications and outcomes achieved by researchers in more recent times.

33 22 Shortly after Gibbons and Bloomer introduced their prosthesis, Aram and Subtelny wrote on velopharyngeal function and cleft palate prostheses. Their study investigated normal velopharyngeal function in order to acquire useful information relative to the positioning of the prosthetic velar lamina.[9] They investigated the approximate level of velopharyngeal closure of children and adults to determine if growth alters the level of closure. In all instances, the soft palate moved in an upward and backward direction to create closure. The soft palate moved a greater amount in older age groups in order to contact the superior and/or the posterior pharyngeal wall. They concluded that, if the velar lamina is positioned above the palatal plane in the region of muscular function, it produces a superior speech aid. Similarly, if the velar lamina is positioned much below the palatal plane, it may obturate the cleft but remain ineffective in assisting velopharyngeal function. Therefore, the velar lamina should be positioned within the region of muscle function, i.e., the nasopharynx. The authors also gave some insight into the characteristics the velar lamina should possess. If the soft palate is completely clefted, the prosthesis can easily extend through the opening of the cleft to the desired level. If the soft palate is short but intact or surgically closed, the velar lamina should follow the oral contour of the resting soft palate and then project upward and backward to reach the desired level within the nasopharynx. The authors state that it must be recognized that individual asymmetrics in pharyngeal function exist which result in differences in the degree and location of pharyngeal movement as well as in soft palate activity which may make it necessary to modify the shape and placement of the velar lamina. The aforementioned statement suggests that a generic velar lamina is less likely to be successful than a velar lamina made to individual patient specifications. For

34 23 the prosthesis to be effective, functional valving must be attained on the anterior, posterior and lateral aspects of the velar lamina within the pharynx. Thus, the velar lamina must contact the posterior pharyngeal wall and be contacted by the muscles of the lateral aspects of the nasopharynx as well as the soft palate during function. The lateral walls of the nasopharynx usually move medially during velopharyngeal function and if the velar lamina is not adequately extended laterally, the muscles of the lateral walls of the nasopharynx will not achieve contact with the velar lamina. This lack of contact results in an opening between the oral and nasopharynx and defeats the purpose of the prosthesis. Therefore, since the lateral walls of the nasopharynx move medially, it would seem that the velar lamina would not have to contact the posterior pharyngeal wall over a very large vertical area. Finally, the mass of the velar lamina should be kept to an absolute minimum in size yet sufficiently bulky to function properly. Aram and Subtelny discussed the positioning and morphology of the prosthetic velar lamina in detail.[9] All removable dental prostheses, to be successful, must be designed to optimize the retention, stability, and support of the prosthesis. Balber attempted to address this aspect as it pertains to the palatal lift prosthesis when he investigated cleft palate patients who had undergone unsuccessful surgical correction and were therefore in need of a speech prosthesis. Balber stated that the speech aid functions by placing an obstruction in the nasopharynx to guide the airflow by means of the muscular activity generated around the obstruction, the speech bulb or the pharyngeal section of the

35 24 velar lamina. During fabrication of the speech aid, the morphology of the obstruction situated in the nasopharynx is formed by molding it to conform with the sphincteric actions of the nasopharyngeal musculature. Here, Balber is in favor of producing a velar lamina with a custom morphology and not a generic morphology. Balber designed his initial prosthesis with the anterior segment of the velar lamina fabricated from a narrow and rounded cast metal bar with the rationale that a low profile would minimally displace the tissue of the soft palate and reduce unseating of the prosthesis. Another design element of this prosthesis was to position the velar lamina behind the soft palate while it was at rest so that the nasal surface of the soft palate could function upon the superior surface of the velar lamina, resulting in velopharyngeal closure occurring in synergy with the functioning pharyngeal musculature. Balber made several prostheses with the aforementioned design characteristics and from his trials he determined that the principal source of difficulty with the prostheses arose from their lack of stability. He deduced that the long lever arm of the velar lamina created poor retention of the prosthesis. He believed that the instability of the prosthesis was not primarily the action of the palatal and pharyngeal musculature since the palatal muscles can only elevate the palate and the pharyngeal section was molded so that upward movement "rides" the soft palate upon the surface of the velar lamina with minimal displacement. Since the pharyngeal musculature contracts primarily in a medial or centripetal direction, their actions should cause essentially equalized forces upon the velar lamina of the prosthesis and cancel each other. Therefore, he attributed the major destabilizing forces to be caused by the actions of the tongue interacting with the prosthesis. The function of the tongue in deglutition is a forceful upward and

36 25 backward movement synchronized with the similar movement of the soft palate. Since the cast bar of the prosthesis is placed on or in close relation to the soft palate, the bar will be impinged upon by the tongue during function and act as a displacing lever. This led Balber to deduce that the solution to this problem would be to permit the bar to move upward with the action of the tongue and soft palate and then to return to its original position when these structures moved downward. He therefore placed a hinge at the junction of the maxillary denture base and velar lamina to permit the upward movement of the velar lamina. Balber stated that this was the first time a hinge would be used with this type of prosthesis. He used inch round orthodontic tubing and 18 gauge round wire to fabricate the hinge. Balber concluded that the hinged prosthesis was stable and exerted minimal stress on the abutment teeth with corresponding high patient acceptance and patient comfort. However, the hinge has not been universally adapted into contemporary prosthesis design.[14] A palatal lift prosthesis with a generic velar lamina made of acrylic was reported in 1968 by Beder, Carrell, and Tomlinson who made the prosthesis for velopharyngeal incompetency patients. The prosthesis, the palatal elevator button (Figure 9), consisted of a maxillary denture base and a velar lamina comprised of a wire connector and a button. The maxillary denture base was either a partial denture framework for a partially edentulous individual or a complete denture for a fully edentulous individual. If a patient presented with an existing prosthesis, it was utilized if it was possible. The

37 26 button of the velar lamina was attached to a loop formed at the distal end of a wire and the opposing mesial end of the wire was attached to the maxillary denture base. The Figure 9 Palatal Elevator Button fabricated by Beder in This prosthesis used a generic velar lamina.[15] Copyright 1968, Elsevier. button was made of cold curing acrylic resin and was approximately 1.5 cm in diameter which was determined to be thick enough to maintain rigidity and to be retained by the loop on the wire. The periphery of the button was rounded to prevent tissue trauma of the soft palate. Beder thought that it might be necessary to elevate the soft palate to a functional level in stages depending upon the acceptance of the prosthesis by the patient as was influenced by the patient s age, physical condition and motivation. The elevation of the palate was obtained by bending the wire cephalad, making the initial bend near its attachment to the maxillary denture base with adjustments made distally in the proximity of the button. With this prosthesis design, Beder introduced a generic

38 27 velar lamina. The generic button was made approximately 1.5cm in diameter without aide of a stone model to create a specific morphology on the palatal surface. Also, the angulation of the velar lamina was not determined from the contours of a model but rather by bending the wire as deemed appropriate by the practioner. Beder indicated that following insertion of his prosthesis, there should be an immediate reduction in hypernasality and perhaps a perceptible reduction in nasal air loss. However, if immediate functional results were not obtained then muscle training exercises should be considered for a patient. Beder thought that if the patient had good action of the pharyngeal sphincter and no pre-existing articulation disorder, then his or her speech should be free of significant nasality and nasal air loss immediately or after a few days of prosthesis use. In patients with a long standing speech disorders, speech therapy was indicated to develop orality in speech and to establish correct neuromuscular patterns of articulation. He advised that adaptation to the prosthesis required some patients to use resting periods within the day until the prosthesis could be worn for a full day. Post-insertion appointments were necessary to monitor that the appliance was retentive and that the tissue in contact with the button remained healthy. The assessment of patients was purely subjective by the author. The palatal elevator button was not accepted as a universal prosthesis design to treat hypernasality.[15] Gonzalez and Aronson studied both velopharyngeal incompetent and velopharyngeal insufficient patients using a prosthesis similar in design to that of Gibbons and Bloomer.

39 28 From their work, they determined that the palatal lift prosthesis has limitations and that the prosthesis should not be used when: 1. Adequate retention is not achievable. 2. The patient has a very spastic or stiff soft palate that will not tolerate elevation. 3. The patient is not willing to cooperate with the treatment. Conversely, their work suggested that the palatal lift prosthesis can be used : 1. To correct or considerably improve palatopharyngeal closure. 2. To stimulate the pharyngeal musculature. 3. As a supportive type of prosthesis to be used until muscles regain complete strength and activity to permit palatopharyngeal closure. 4. As a temporary or permanent means to correct hypernasality and nasal emission in speech. Speech therapy was provided to patients who demonstrated need as determined by the researchers. With use of a palatal lift prosthesis the major improvements demonstrated by the patients were reduced hypernasality and nasal emission, increased rate of articulation, and increased overall speech intelligibility.[16] Similar to Gonzalez and Aronson, Kipfmueller and Lang studied both velopharyngeal incompetent and velopharyngeal insufficient patients that required a palatal lift prosthesis with a velar lamina that simply elevated the soft palate or replaced and elevated the soft palate, respectively. The velar lamina was fabricated so that from the maxillary denture base, it projected downward and then upward behind the residual soft palate into the pharyngeal cavity. The velar lamina was molded by means of a functional impression of the muscular action of the posterior and lateral pharyngeal walls that assisted velopharyngeal closure. The prosthesis, termed palatal lift, for the

40 29 velopharyngeal incompetent patient had a broad, straight and comparatively flat velar lamina that was used to simply lift the soft palate. The prosthesis, termed modified palatal lift, for the velopharyngeal insufficient patient had a velar lamina that was modified by the addition of a small acrylic resin extension added to the posterior border that permitted contact with the posterior pharyngeal wall to achieve complete closure of the velopharyngeal valve. Since the soft palate was lifted by both prostheses, they both increased the volume for oral sound production and the physical size of the velar lamina in the pharyngeal space was greatly reduced from the dimensions which would have been required if a fixed type of cleft palate prosthesis had been utilized. The patients were used as their own control, with and without the prosthesis, and they were assessed in terms of speech intelligibility, nasality and radiographic cephalometric analysis was performed of the velopharyngeal valve during function. The palatal lift and modified palatal lift speech prostheses had a marked effect on intelligibility of speech as was shown by a reduction in errors of consonant identification by untrained listeners. Trained listeners judged the prostheses to provide an improvement in articulation skill. The effects of the prosthesis on improved identification of consonants was most uniformly beneficial for those patients with insufficient velopharyngeal closure. The study concluded that the palatal lift and modified palatal lift speech prostheses were effective in assisting with obturation of insufficient and incompetent velopharyngeal mechanisms.[17]

41 30 Mazaheri and Mazaheri wrote an important paper on prosthodontic aspects of palatal elevation and palatopharyngeal stimulation in They described the palatal lift prosthesis (Figure 10, topabove) and the combination bulb lift prosthesis (Figure 10, bottom) used for velopharyngeal incompetency and velopharyngeal insufficiency, Figure 10 (above) Palatal Lift Prosthesis. (A) Prior to soft palate stimulation by a palatal lift prosthesis. (B) Elevated soft palate with the palatal lift prosthesis in place. (below) Combination Lift Bulb Prosthesis. (A) Short soft palate and large nasopharynx. (B) Combined lift bulb prosthesis in place.[6] Copyright 1976, Elsevier. respectively. They stated that the palatal lift prosthesis may stimulate the soft palate muscles and help eliminate palatal disuse atrophy. They suggested that the palatal lift prosthesis may also be used as a temporary or definitive treatment for palatal incompetency. They thought that when adequate elevation of the soft palate had been achieved, in some instances the prosthesis could be discarded but in other situations the patient may be required to wear the prosthesis as a permanent supportive device. The combination bulb lift prosthesis was utilized when the soft palate was too short to achieve proper velopharyngeal closure. The construction of the combination bulb lift prosthesis required gradual elevation of the soft palate and functional molding of the

42 31 velar lamina in the pharynx to reduce the patient s gag reflex and increase velopharyngeal muscle adaptation to the prosthesis. Since a gradual elevation was used during the construction of the velar lamina during the initial placement of the prosthesis, they stated that adjustment to the velar lamina in the pharynx would be easier for the patient. This factor would therefore suggest that insertion of a generic velar lamina would be more difficult initially for a patient and perhaps more than one generic velar lamina would be required to step-up the size of the velar lamina over time. The authors summarized that to fabricate an effective combination bulb lift prosthesis, the following pre-requisites were required: 1. The maxillary denture base needs to achieve optimal retention and stability. 2. The velar lamina needs to be oriented to lift the palate in the region where normal velopharyngeal closure occurs. 3. Elevation of the soft palate should occur gradually so that the soft palate becomes less resistant to displacement which places less pressure upon teeth retaining the prosthesis and reduces mucosal irritation. 4. The portion of the velar lamina in the pharynx should be positioned in the region where constriction of the posterolateral pharyngeal wall occurs to encourage muscle stimulation and activity. 5. Reduction of the velar lamina in the pharynx should be gradual if required. 6. The patient should undergo speech and myofunctional therapy in conjunction with prosthesis fabrication. None of the aforementioned pre-requisites preclude the use of a generic velar lamina. Apart from specific recommendations applicable to the combination bulb lift prosthesis, the authors also stated objectives to be achieved by either type of prosthesis as follows: 1. To reduce hypernasality and the escape of nasal air by palatal elevation. 2. To reduce the degree of palatal tissue atrophy prosthetic stimulation should be initiated as soon as palatal paralysis is noted to prevent palatal disuse atrophy.

43 32 3. To increase velopharyngeal function by constant and continuous stimulation. 4. To increase neuromuscular response by gentle stimulation and speech exercises. 5. To assist in the repositioning of the tongue. The authors stated that a patients' tolerance of prosthetic treatment will vary from one individual to another, as is the case with any oral prosthesis. If a patient has little or no speech articulation disorder then prosthetic treatment is most advantageous. However, patients with muscle paralysis of the tongue, lips, larynx and respiratory organs usually respond less favorably to prosthetic treatment. Similar variability exists with a patient's muscle response to mechanical stimulation of the soft palate, which may or may not become more active. In some patients, after six months to a year of prosthesis wear the prosthesis may be discarded due to a positive functional recovery from prosthetic stimulation. Conversely, patients that receive speech therapy as their sole mode of velopharyngeal stimulation show less noticeable functional recovery. There can be a marked nasopharyngeal muscle response to prosthetic stimulation that results in the development of compensatory muscle contraction and that subsequently requires frequent reduction in the size of the velar lamina of the prosthesis residing in the pharynx. The authors noted that there are even times when the section of the velar lamina residing in the pharynx can be completely eliminated. Tissue response to prosthetic stimulation varies between patients with velopharyngeal incompetence and velopharyngeal insufficiency. In summary, the objective with velopharyngeal incompetence is to stimulate muscle activity by prosthetic-physical therapy and for

44 33 velopharyngeal insufficiency the objective is to develop muscle power or contraction by placement of the prosthesis.[6] Shortly after Mazaheri and Mazaheri published their findings, LaVelle and Hardy published their work on prosthodontic management of palatopharyngeal incompetency due to etiologies other than cleft palate. Their observations were not completely congruent with Mazaheri and Mazaheri. LaVelle and Hardy argued that the use of a palatal lift prosthesis was the most effective type of management of velopharyngeal dysfunction. They states that successive additions to the velar lamina of the prosthesis with intervening periods of time were desirable in order to offset tissue intolerance problems and to allow the patient time to adapt to wearing the prosthesis, especially those with a strong gag reflex (Figure 11). Figure 11 (left) Palatal lift prosthesis that elevates the patient s soft palate along the midline superiorly. (right) Palatal lift prosthesis with a narrow palatal projection to bypass taut anterior faucial pillars (palatoglossus muscles) and with extensive posterior lateral projections to lift the soft palate into the lateral velopharyngeal port areas.[18] Copyright 1979, Elsevier.

45 34 The authors aimed to complete the molding of the velar lamina in one session with the functional impression occurring in a staged fashion. Instead of using a single velar lamina morphology, they adapted the outline form of the velar lamina that best satisfied the needs of the patient. From an initial alginate impression, an acrylic maxillary denture base was produced that had a posterior wire extension that was used to retain thermoplastic impression material. A functional impression was taken with the thermoplastic impression material to form the velar lamina. Immediately after the impression, some patients showed improvements in speech with the prosthesis in place. At intervals during the segmental addition of thermoplastic impression material, an oscilloscope was used to assess nasal airflow rates, intraoral air pressures, and display a speech waveform. With these methods, the authors assessed the effectiveness of the velar lamina during the impression process. Reductions in nasal airflow rates and increases in intraoral air pressures during speech provided gross indications that the velopharyngeal port area was decreasing. Typically, two problems could possibly have occurred during the functional impression of the velar lamina that caused the impression to be suspended short of an optimal result. First, the soft palates of some patients became quite taut as the thermoplastic impression procedure continued, causing the soft palate to slip onto the superior surface of the prosthesis. The authors observed that it was preferable to stop short of stretching the tissue to that point because a satisfactory result was usually achieved when the soft palate draped around the lateral and posterior edges of the prosthesis to form a seal with the pharyngeal walls. Second, if the patient's velopharyngeal muscles were hypertonic, severe pain in the lateral pharyngeal area, particularly during swallowing, and

46 35 excessive pressure on the palatal tissue resulted as the prosthesis was being enlarged. In addition, the glossopharyngeal muscles (anterior faucial pillars) of these patients may have moved medially upon insertion of the prosthesis. To compensate for this movement, the authors suggested that the resultant stretch of the soft palate tissues be reduced by molding the velar lamina narrow near its connection with the maxillary denture base, Figure 11 (right). Also, if it was necessary to close the lateral ports, lateral expansion of the velar lamina could be accomplished posterior to the pillars when the prosthesis was in place. When optimal results could not be obtained due to taut palatal muscles and/or hypertonic velopharyngeal muscles, or the presence of a strong gag response, the decision to terminate the functional impression was made since there was little to be gained for the patient. On delivery of the prosthesis patients were asked to wear the prosthesis for the first few days and even sleep with the prosthesis if it was possible. This is a differing approach than permitting the patient a slow transition into wearing the prosthesis. If pain was associated with swallowing, then the prosthesis was not used during eating but the patients were still encouraged to try and adapt eating with the prosthesis. Patients with gagging problems were usually able to adapt within 2-3 days of prosthesis use but it could take weeks to use the prosthesis to eat. Minor ulcerations from prosthesis use, similar to denture sores, were resolved by relief and polishing of the prosthesis. Patients that were unable to complete the initial functional impression of the velar lamina to optimal results were recalled 2-3 months after prosthesis delivery to

47 36 continue the functional impression by addition of thermoplastic impression material to the velar lamina of the acrylic prosthesis to see if further progress could be obtained. The prosthesis was then reprocessed as required by the success of the second functional impression appointment. From the study, the authors ascertained that the patient needs to have some pharyngeal wall function, for optimum results. If the palatal, pharyngeal, and glossopharyngeal muscles have relatively normal muscle function or are hypotonic. it is preferred over hypertonic muscles since velopharyngeal port closure is easier to obtain. The presence of adequate soft palate tissue is also a benefit since it permits easier contact with the pharyngeal walls and velopharyngeal port closure. Finally, they felt that it was unrealistic to expect that through the use of a prosthesis velopharyngeal port function during speech would improve to a state where discarding of the prosthesis was a viable option. In contrast to Mazaheri and Mazaheri, they felt that the prosthesis would not increase velopharyngeal function by constant and continuous stimulation.[18] The work by Sato involved a palatal lift prosthesis for use specifically with edentulous patients (Figure 12). Generally speaking, an edentulous patient requires a good border seal of their complete denture for retention of the prosthesis. With the addition of a rigid velar lamina to the posterior of a complete denture, which is serving as the maxillary denture base, the border seal can be compromised with subsequent dislodgement of the prosthesis. Sato suggested the addition of a movable velar lamina by means of elastic nickel-titanium orthodontic wire joining the velar lamina to the

48 37 maxillary denture base as a solution for retention issues. A cephalogram of the patient was used to guide the alteration of a diagnostic cast in the area of the soft palate to Figure 12 Palatal lift prosthesis for a fully edentulous patient with nickel-titanium wires joining the velar lamina to the complete denture.[19] Copyright 1987, Elsevier. simulate the desired raised contour of the soft palate. A custom tray was fabricated from the altered diagnostic cast for an impression and a master cast was made. A complete denture was produced with a fixed velar lamina with openings for weight reduction. The complete denture and the velar lamina were processed separately and then placed back on the master cast. A duplicate was made and nickel-titanium wires were embedded in both sections with auto-polymerizing resin to connect the sections to one another. The velar lamina elevated the soft palate by the intrinsic force of the elastic nickel-titanium orthodontic wires. The authors noted that the elastic property of the nickel-titanium wires should be specifically selected for each patient based on the retention of the maxillary denture base and the force required to elevate the soft palate. The prosthesis improved both speech and swallowing and was thought to be a useful prosthetic option for edentulous patients with hypernasal speech. The attachment of

49 38 the velar lamina to the maxillary denture base with nickel-titanium wire was a unique modification of the palatal lift prosthesis but it has not been accepted for general use when fabricating palatal lift prostheses.[19] Another example of a unique material for a palatal lift prosthesis was suggested by Spratley, Chenerey, and Murdoch. They described a palatal lift prosthesis that integrated a unique, but commonly used, dental material for construction of the velar Figure 13 Palatal lift prosthesis fabricated with a thermo-softened vinyl velar lamina.[20] Copyright 1988, John Wiley & Sons, Inc. lamina of their prosthesis (Figure 13). Since there is significant movement in the velopharyngeal region during speech and swallowing, a rigid velar lamina would not be able to provide adequate palatal support and remain comfortable for a patient. Their redesigned palatal lift prosthesis incorporated a hinged velar lamina and was fabricated for patients with neurogenic velopharyngeal incompetence. To fabricate the prosthesis,

50 39 an extended impression including the soft palate was made to produce a dental stone master model. Their final design incorporated a hinge made from twin 0.5mm orthodontic wires that could be adjusted to change the elevation of the soft palate. The velar lamina was initially produced with self-curing acrylic resin but tissue trauma resulted and addition of a soft liner to the acrylic did not improve the situation. The velar lamina was then produced from a high molecular mass copolymer vinyl mouthguard material. The thermoplastic vinyl mouthguard material was softened with hot water and adapted to the soft palate on the master model with the hinge pushed into the material until it was submerged. The vinyl mouthguard material was finished with a small flame and then chloroform. This material choice provided for a softer and more flexible velar lamina. The authors had mixed results with the prosthesis and they did indicate that there was a concern over the longevity of softer material being used for the velar lamina. With the incorporation of vinyl to produce the velar lamina, a softer material is again tried as was seen in the nineteenth century and, once again, we see the reemergence of the hinge in a palatal lift prosthesis.[20] Wolfaardt reported on a clinical pilot project that had the aim of developing a protocol for treatment of palatopharyngeal incompetency. This work described how a palatal lift prosthesis, similar to Gibbons and Bloomer, was constructed but more importantly delivered a methodical approach on how to determine if a patient would benefit from a palatal lift prosthesis. Determining if a patient would benefit from a prosthesis was important since the use of a palatal lift prosthesis remained controversial relative to

51 40 patient selection. The objectives of this report were to describe the method of patient selection, the technique of prosthesis fabrication, speech therapy with the prosthesis, and the results of treatment with the palatal lift prosthesis. The patient selection was determined by assessing the following: 1. Interview of the patient and his or her family. 2. An assessment of the anatomic structures of the patient. 3. Instrumental assessment of the patient involving: a. Acoustical assessment of palatopharyngeal competence. b. Aeromechanical (pressure flow) assessment of palatopharyngeal competence. c. Audio tape recording. d. Flexible fiber-optic video nasendoscopy (FFVN). 4. Treatment modality selection. With all the data collected from the multidisciplinary group, comprised of three speech language pathologists and a prosthodontist, it was determined that a palatal lift prosthesis to manage palatopharyngeal incompetence was appropriate when: 1. The palatopharyngeal dysfunction is caused by a neurologic or physiologic condition that makes the patient a poor risk for surgical intervention (upper airway valves other than the palatopharynx should not be too impaired). 2. Perceptual and instrumental signs of palatopharyngeal incompetence are chronic but mixed, inconsistent, borderline, or some combination thereof, but management is warranted to normalize resonance balance and facilitate oral language development. 3. The clinical team wants to have an improved speech model before palatopharyngeal surgery. 4. The physical size of the pharyngeal space as determined by FFVN and Palatal Efficiency Rating Computed Instantaneously (PERCI) is considered reasonable for achieving closure with the palatal lift prosthesis. 5. The patient and social factors listed in the Treatment Modality Selection questionnaire, see Appendix 1[21], are considered positive in indicating the use of a palatal lift prosthesis. 6. The patient and/or caregiver(s) do not wish to pursue surgical management.

52 41 Once the assessment was complete, the patient could undergone no treatment, behavioural management, surgical intervention, or prosthetic intervention. When prosthesis fabrication was selected, the patient also underwent articulation therapy, auditory training and perhaps a systematic time-based reduction of the prosthesis to possible complete elimination of the prosthesis. The palatal lift prosthesis fabricated in this study benefits from increased retention afforded by orthodontic bands. Buccal tubes were bonded to the maxillary molars to permit undercuts for the clasps of the prosthesis to engage. The velar lamina of this prosthesis was developed through a functional impression technique. Wolfaardt made the following statement regarding the functional impression technique to produce a palatal lift prosthesis: "This technique produces a functionally generated palatal lift that has anatomic relation to the elevated soft palate that is advantageous over an arbitrarily contoured lift". Hence a generic velar lamina is considered less effective than one derived functionally. Upon delivery of the prosthesis, the patient was required to attend speech therapy sessions. The speech therapy techniques utilized included auditory and articulation training. A timebased reduction program was also considered for each patient and administered when appropriate. Generally, after 12 to 18 months of successful prosthesis use, a patient would have been considered for such a program. The particulars of the reduction program were developed on a patient by patient basis. Of the patients entering a reduction program, 66.7% (14 out of 21) were able to completely eliminate the prosthesis. The study concluded that a substantial portion of the patients benefited from the palatal lift prosthesis, that a palatal lift prosthesis could assist in treating

53 42 palatopharyngeal incompetence, and that a protocol was developed for treating palatopharyngeal incompetency.[21] The production of a palatal lift prosthesis using a velar lamina made of silicon has been reported by Vogel, Sauermann and Ziegler. They state that a velar lamina made of a rigid material produces a pressure from the cantilever effect of the velar tissue pressing against the posterior most aspect of the velar lamina. When combined with the high degree of movement in the velopharyngeal region, the rigid acrylic may predispose the patient to tissue irritation, discomfort, and stimulate a gag response. They fabricate a palatal lift prosthesis from a maxillary impression that nearly reaches the posterior pharyngeal wall. The velar lamina was made from a 3mm sheet of silicon rubber and took approximately minutes to form using a polishing disk. The silicon could be made paper thin at the edges and this permitted the silicon to cling to the adjacent tissue without discomfort to the patient. A patient may need a series of velar laminae produced before the definitive velar lamina morphology is obtained. They achieved an optimal result when the velar lamina nearly approximated the lateral and posterior pharyngeal walls. This fit permits a patient to inhale through the nose but exhaling through the nose is extremely limited. A typical prosthesis has a life span of at least 6 months and usually fails due to the steel extension perforating the silicon velar lamina. The authors state that their prosthesis minimizes tolerance problems, improves speech intelligibility of patients in nearly all cases, and can have a catalytic effect on the motor speech mechanism in general. This prosthesis uses a silicon velar lamina that is

54 43 custom sculpted for each patient and demonstrates that silicon is a viable option for use in velar lamina construction.[22] Over the last 54 years, the palatal lift prosthesis described by Gibbons and Bloomer remains as the template for the contemporary palatal lift prosthesis. Even the dental materials used in constructing the palatal lift prosthesis have remained consistent. Alterations to the prosthesis have been attempted but none have made a lasting impact. Attempts have been made to utilize a generic velar lamina but the standard velar lamina is fabricated through a functional impression technique. 1.5 CHRONOLOGICAL REVIEW OF EVALUATION/OUTCOME MEASURES FOR PROSTHETIC TREATMENT OF VPD It is important to consider the treatment outcomes of prosthetic intervention to determine if the prosthetic therapy is beneficial to the recipient. The evaluation and outcome measures of select studies and reviews that have been employed to determine the benefit of prostheses fabricated to address VPD are summarized in Table 1. Table 1 Chronological Review of Evaluation/Outcome Measures for Prosthetic Treatment of VPD. Year Author(s) Title Journal Evaluation/Outcome Measures Lateral profile cephalogram analysis A supportive-type Observations and tests of Gibbons and The Journal of prosthetic speech palatopharyngeal function. Bloomer Prosthetic Dentistry aid[8] Acoustic spectrograms of patients speech. Subjective speech evaluation Aram and Subtelny Velopharyngeal function and cleft palate prostheses[9] The Journal of Prosthetic Dentistry Lateral cephalometric roentgenography.

55 Balber 1967 Lang Beder, Carrell, and Tomlinson Lang and Kipfmueller Gonzalez and Aronson Marshall and Jones Kipfmueller and Lang Mazaheri and Mazaheri La Velle and Hardy 1986 Shprintzen Cleft palate prosthesis without surgical redivision[14] Modification of the palatal lift speech aid[23] The palatal elevator button[15] Treating velopharyngeal inadequacy with the palatal lift concept[24] Palatal lift prosthesis for treatment of anatomic and neurologic palatopharyngeal insufficiency[16] Effects of a palatal lift prosthesis upon the speech intelligibility of a dysarthric patient[25] Treating velopharyngeal inadequacies with a palatal lift prosthesis[17] Prosthodontic aspects of palatal elevation and palatopharyngeal stimulation[6] Palatal lift prostheses for treatment of palatopharyngeal incompetence[18] Evaluating Velopharyngeal Incompetence[26] The Journal of Prosthetic Dentistry The Journal of Prosthetic Dentistry The Journal of Prosthetic Dentistry Plastic and Reconstructive Surgery The Cleft Palate Journal The Journal of Prosthetic Dentistry The Journal of Prosthetic Dentistry The Journal of Prosthetic Dentistry The Journal of Prosthetic Dentistry Journal of Childhood Communication Disorders Subjective assessment of speech. Pre-treatment speech recordings. Lateral cephalometric roentgenography. Lateral cephalometric roentgenography. Subjective assessment of speech. Lateral cephalogram analysis. Speech analysis: Fairbanks Rhyme Test of Phonemic Differentiation (1958), systematic analysis. Listener evaluation: untrained in phonetics or speech pathology. Tape-recorded speech assessment. Cephalogram and cineradiographic film analysis. Clinical observations of speech. Follow-up observations. Lateral skull radiographs. Tape-recorded speech assessment. Six naive listener judges. Lateral skull cephalograms. Fairbanks Rhyme Test recordings to assess intelligibility of speech by 25 untrained listeners. Sentence Test, devised by Van Demark, recordings to assess articulation and nasality by 8 trained listeners. Speech testing procedures. Radiographic evaluation (cineradiography, cephalometrics, sectional laminography, or tomography). Devices for assessing oral nasal air pressure and air flow. Electronic instrumentation such as tonar and sonograph. Cephalometric radiograph analysis. Tape-recorded speech assessment. Palatopharyngeal port area measurements (rates of nasal airflow and intraoral air pressures). Storage oscilloscope anaylsis of nasal airflow rates, intraoral air pressures, and a display of the speech signal during prosthesis fabrication Cinefluorographic film analysis: select usage. Indirect Diagnostic Techniques: Listener judgement. Oral manometry, nasal manometry, tonar, pressure-flow, spirometry, anemometry, and accelerometry. Direct Diagnostic Techniques: Radiographic procedures. Endoscopic procedures. Current State of the Art: Multi-view videofluoroscopy. Nasopharyngoscopy.

56 Sato, Sato, Yoshida, and Tsuru Spratley, Chenerey, and Murdoch Turner and Williams Wolfaardt, Wilson, Rochet, and McPhee Kummer and Lee Shifman, Finkelstein, Nachmani, and Ophir 2003 Abdel-Haleem 2011 Stelck, Boliek, Hagler, and Rieger Palatal lift prostheses for edentulous patients[19] A different design of palatal lift appliance: review and case reports[20] Fluoroscopy and nasoendoscopy in designing palatal lift prostheses[27] An appliance based approach to the management of palatopharyngeal incompetency: a clinical pilot project[21] Evaluation and Treatment of Resonance Disorders[28] Speech-aid prostheses for neurogenic velopharyngeal incompetence[29] Protocol of assessment of velopharyngeal incompetence[30] Current practices for evaluation of resonance disorders in North America[31] The Journal of Prosthetic Dentistry Australian Dental Journal The Journal of Prosthetic Dentistry The Journal of Prosthetic Dentistry Language, Speech, and Hearing Services in Schools The Journal of Prosthetic Dentistry International Congress Series Seminars in speech and language Intraoral pressure analysis. Single sound analysis. Cineradiograph analysis. Contextural speech analysis. Videoradiography. Perceptual ratings by 5 speech language pathologists. Electroacrometer analysis (nasal emission). Oral assessment. Speech Assessment (resonance and speech articulation). Oronasal air flow measures. Videofluorographic assessment. Videonasoendoscopic assessment. Interview of individual and family. Assessment of anatomic structures. Instrumental assessment: Acoustical assessment of palatopharyngeal competence. (Nasometer) Aeromechanical (pressure flow) assessment of palatopharyngeal competence. (PERCI) Audio tape recording. Flexible fiber-optic video nasendoscopy (FFVN). Speech therapy. Time-based reduction program. Perceptual evaluation (The Iowa Pressure Articulation Test, a part of the Templin-Darley Tests of Articulation). Instrumental assessment (nasometer) Intra-oral examination. Videoflouroscopic speech study. Nasopharyngoscopy (endoscopy). Speech evaluation (intelligibility, phonation, resonance, and nasal emission). Video-nasopharyngoscopic and multiview videofluoroscopic examinations. Cineradiography and videofluoroscopy. Video-endoscopy. Aeromechanical devices. Acoustic measures. Electromyography. Perceptual assessment. Orofacial examination. Nasometry. Speech aerodynamics. Videofluoroscopy. Nasopharyngoscopy. From Table 1 it can be seen that evaluation and outcome measures have evolved from assessment strategies that have a greater subjective component; transitioning to more objective assessment strategies over time. A recent study by Stelck, Boliek, Hagler,

57 46 and Rieger state that the best practices, according to the literature and expert opinion, for assessment strategies to evaluate resonance disorders are perceptual assessment, orofacial examination, nasometry, speech aerodynamics, videofluoroscopy, and nasopharyngoscopy.[31] However, the authors acknowledge, often best practices can not be applied due to barriers, such as lack of access to equipment, that prevent an ideal assessment of a patient. To illustrate this point, 42.1% of respondents questionned never use nasometry to assess a patient. Of those respondents 68.8% never use nasometry because they do not have access to the instrumentation but 62.5% of those same respondents would use nasometry if it was accessible to them.[31] 1.6 RATIONALE Hypernasality is a significant speech problem experienced by a myriad of patients with velopharyngeal insufficiency or incompetency. The speech intelligibility and subsequent speech acceptability of a patient can be negatively affected due to a hypernasal distortion of the normal resonance in the vocal tract. The prosthetic solution to address hypernasality has been applied successfully to aid in the reduction of the associated negative effects. However, even though success is well documented, a speech prosthesis is not necessarily easily attainable by a patient. This is perhaps due to the skill required and time involved in prosthesis production and maintenance. Consequently, the treatment carries a higher cost that may in itself also serve as a barrier for a patient. The primary purpose of this study is to determine if a modified

58 47 version of the contemporary speech prosthesis to address hypernasality can overcome the aforementioned obstacles to prosthetic therapy by serving as a generic, modular and consequently low-cost alternative. 1.7 OBJECTIVES The objectives of this study are as follows: To determine if a generic velar lamina made from silicon can be tolerated by a patient and function to reduce hypernasality. To determine if the removable connection used in the Toronto Palatal Lift Prosthesis to unite the velar lamina with the maxillary denture base is a practical method for connection of these components. To compare the results obtained with the experimental Toronto Palatal Lift Prosthesis to the contemporary acrylic prostheses used to treat hypernasality. 1.8 HYPOTHESIS The null hypothesis is that the experimental Toronto Palatal Lift Prosthesis, made with a generic silicon velar lamina, is not equal or superior to a contemporary acrylic speech prosthesis to address hypernasality. The alternative hypothesis is that the experimental Toronto Palatal Lift Prosthesis will provide equal or superior results to a contemporary acrylic speech prosthesis to address hypernasality. The TPLP will improve patient outcomes in speech therapy (ie. reducing hypernasality and improving

59 48 prosthesis tolerance/adaptation), reduce production costs, and simplify prosthesis fabrication and maintenance.

60 2.0 MATERIALS AND METHODS 2.1 SETTING This study was conducted at the Department of Dentistry and Maxillofacial Prosthetics of the Princess Margaret Hospital (Toronto, Ontario). Speech recording evaluations took place at the Voice and Resonance Lab at the University of Toronto (Toronto, Ontario). Ethics approval for this study was granted by the University Health Network Research Ethics Board on June 22, 2011 and has been maintained to date, see Appendix INCLUSION CRITERIA The inclusion criteria for this study were as follows: 1. Velopharyngeal insufficiency or velopharyngeal incompetency that results in a hypernasal resonance disorder, resulting from head and neck cancer, a craniofacial syndrome such as cleft palate, a neurogenic disorders such as a stroke, or other structural or neurogenic disorders. 2. Patient to receive a palatal prosthesis (speech bulb or lift), as determined by the referring physician or dentist and as confirmed by Dr. Al Mardini, the maxillofacial prosthodontist at the Princess Margaret Hospital. 3. Patient 16 years of age or older. 49

61 EXCLUSION CRITERIA The exclusion criteria for this study were as follows: 1. Patients under 16 years of age. 2. Patients ineligible for an oral prosthesis or other intraoral appliance because of severe cognitive or mobility limitations. 2.4 SAMPLE SIZE Patients were recruited from the Department of Dentistry and Maxillofacial Prosthetics at the Princess Margaret Hospital and served as their own control. A convenience sampling approach was used for the study. To determine the sample size, the expected nasalance scores with and without speech prostheses were considered. A nasalance score of 40% with a standard deviation of 10% was assumed for the patients without a speech prosthesis and a nasalance score of 25%, with a standard deviation of 5%, was assumed for patients with a speech prosthesis. Based on these values for a double sided distribution with an alpha of 0.05 and a power of 0.9, we required a minimum sample size of PATIENT POPULATION Patients enrolled in the study were screened by Dr. Al Mardini, the maxillofacial prosthodontist at Princess Margaret Hospital. The patient demographics are detailed in Table 2.

62 51 Patient Sex Age Diagnosis Medical / Social history Velopharyngeal insufficiency 1 F 38 Mandibulofacial Multiple surgeries dysostosis Never smoked, social drinker Treacher Collins syndrome 2 M 73 3 F 32 4 M 48 5 F 26 6 F 66 Velopharyngeal insufficiency Squamous cell carcinoma of tongue Velopharyngeal insufficiency Oropharyngeal fistula Velopharyngeal insufficiency Chronic Aspergillus infection in 2008 for 2 years duration. Velopharyngeal incompetency Due to congenital defect. Velopharyngeal incompetency Primary lateral sclerosis Hypertension, knee surgery, GERD Mandibulotomy (June, 2008) Smoked but quit, 50 pack/ ys Migraines, scoliosis Smoker, 15 pack/ys Headaches - infection related, tonsillectomy, knee surgery, curettage of sinus Smoker, 30 pack/ys Soft palate very short. Ulcer 10x15 mm on posterior pharyngeal wall at level of soft palate. Painful, takes oxycontin for management. Possible allergy to sulfa drugs Hyperactive gag reflex Hypertension, aorta heart valve replacement, arthritis, primary lateral sclerosis, osteoporosis, broken left hip (October, 2011), medicated bipolar disorder since 1987 Used to smoke but quit Table 2 Patient demographic information. First seen at PMH 27-May Apr Jul Apr Total Study Visits Jan May POTENTIAL PATIENT RISKS OR COMPLICATIONS All procedures performed in this study were minimal risk. The experimental treatment procedures were fully equivalent to, or less involved than, the regular interventions associated with the fabrication and insertion of a conventional acrylic palatal lift prosthesis. The patients received detailed instructions about the use and maintenance of the prosthesis. This information was included on information sheets (see Appendix

63 52 3) that the patients took home for reference after they agreed to participate in the study. For safety reasons, the prosthesis was not to be worn during meals, during physical exercise and during sleep. There may have been discomfort during the initial insertions of the prostheses in patients with a sensitive gag reflex. If gagging occurred, the prostheses was simply removed. Any soft tissue ulcerations that developed due to either prosthesis type were addressed by reduction and subsequent polishing of the prosthesis in the offending area. There were no risks associated with the speech recordings in this study. No adverse reactions were expected to the TPLP since the materials used to construct the prosthesis are standard dental materials for intraoral use. If a patient experienced a problem or discomfort, they were instructed to simply remove the prosthesis and consult with one of the investigators to discuss potential solutions. All participants received a contact phone number should there be questions or concerns. 2.7 DATA COLLECTION AND OUTCOME MEASURES Once a patient could function with a prosthesis and had been given sufficient time to adapt to the prosthesis as optimally as possible, as deemed by the clinician, the patient underwent a series of speech evaluations and completed a subjective feedback questionnaire. The adaptation time given to the patient was flexible and depended on numerous variables, such as previous prosthesis exposure, required prosthesis velar lamina extension, and presence of a gag reflex, to name a few. One battery of speech

64 53 recordings took approximately ten minutes and was not an onerous task for a patient to complete. If a patient was to undergo multiple speech recordings during the same session then the sequence of the recordings was administered randomly. Data collected from the speech recordings were used to establish a nasometric assessment and speech acceptability assessment score for each patient NASOMETRIC ASSESSMENT The patients completed a nasometric assessment with and without prostheses to assess their resonance in different speaking conditions.[32] The Nasometer Model 6400 (KayPENTAX, Montvale, NJ, USA) was used to record each patient reading, or repeating after the examiner, the Zoo Passage (a text without nasal consonants) and the Nasal Sentences (a text loaded with nasal consonants), see Appendix 4.[33, 34] The Nasometer was selected as a speech assessment instrument for this study because it has been previously utilized for diagnosis and research with a wide variety of different languages and disorders.[34] The data gathered from the nasometric assessment was used to calculate the mean nasalance values for each patient SPEECH ACCEPTABILITY ASSESSMENT In order to assess speech acceptability the sentence module of the computerized Test of Children s Speech (TOCS+) was utilized.[35] The TOCS+ program presents stimuli visually and acoustically for a patient to repeat and the program records a data file of

65 54 the interaction. The data selected for evaluation for each patient were sentences of five words or more. The data was evaluated by seven naïve listeners and the acceptability of the sentence was judged using a four-point rating scale (normal to severe).[36, 37] The naïve listeners were presented with a laptop computer, headphones (Ear Force DX 12, Voyetra Turtle Beach, Valhalla, NY, USA), and a spreadsheet containing a randomized sample of 63 data samples that included 9 data samples from each patient and 9 control data samples from normal speakers. Of the 9 data samples from each patient 3 were without a prosthesis, 3 were with the conventional prosthesis, and 3 were with the TPLP. The naïve listeners selected to assess the data samples all have a background in dentistry SUBJECTIVE PATIENT FEEDBACK QUESTIONNAIRE After the speech recordings were completed, patients used five-point rating scales to assess their subjective comfort with the prostheses and their subjective satisfaction with their own speech on a questionnaire, see Appendix 5. The questions comprising the subjective feedback questionnaire were: "When I wear my prosthesis my speech is...", "When I wear my prosthesis I have to gag/choke...", "When I wear my prosthesis my speech feels...", and "When I wear my prosthesis my swallowing feels...". The data collected from these questions was used to interpret how patients feel without a prosthesis and any potential difference when using a conventional prosthesis or TPLP.

66 STATISTICAL ANALYSIS Data was analyzed using SPSS software. The outcome measurements obtained from the patients without a prosthesis or with a TPLP or a conventional acrylic prosthesis were compared using the Wilcoxon Signed Ranks Test. Comparisons were not Bonferroni-adjusted, based on the recommendation by Pernerger.[38] Statistical analysis was limited to descriptive statistics for this study. 2.9 FABRICATION OF THE TPLP The TPLP is based on a generic velar lamina and therefore required the fabrication of a mold for production of the velar laminae. The union of the maxillary denture base to the velar lamina adopted by the TPLP required modifications to the steps taken if producing a conventional speech aid/ palatal lift prosthesis. The fabrication instructions required to produce a TPLP are outlined in the following sections MATRIX TRANSFER MOLD- FABRICATION The initial prototype of the velar lamina with an obovate outline form was fabricated from galvanized sheet metal used in duct fabrication, wax (Baseplate Wax- pink regular No. 2, Kerr Dental Laboratory Products, Orange, California, USA) and orthodontic wire (Tru-Chrome Stainless Steel Retainer Clasp Wire- Round inch/18 gauge, Rocky Mountain Orthodontics, Denver, Colorado, USA), Figure 14. An obovate outline form was initially selected since it is a frequently generated outline form for palatal lift

67 56 Figure 14 (left) First velar lamina prototype with an obovate outline form. (right) Second velar lamina prototype with a truncate ovate outline form. prostheses. A matrix transfer molding process was employed by using the two halves of a standard denture flask (No. 31 Ejector Flask, Buffalo Dental Manufacturing Co. Inc., Syosset, New York, USA) as the rigid outer shell of the mold. Into the denture flask halves was added a combination of an external dental stone layer (Microstone, Whip Mix Corp., Louisville, Kentucky, USA), to reduce the volume of polyvinylsiloxane (PVS) required, and an internal laboratory grade PVS (Zetalabor, Zhermack SpA, Badia Polesine, Italy) layer as the inner molding material to capture the details of the prototype. Prior to placing the prototype in the PVS layer of the matrix transfer mold a small volume of laboratory grade PVS was mixed and adapted around the wire extensions of the prototype and formed into a rectangular solid to encapsulate the wire extensions and permitted to cure. Once cured an orientation groove was cut into an external wall of the rectangular solid to provide orientation of the velar lamina wire in the matrix transfer mold during the fabrication of the velar lamina. Petroleum jelly (Vaseline Original Petroleum Jelly, Unilever Canada Inc., Toronto, Ontario, Canada) was used as a separating agent and was applied to all external surfaces of the

68 57 rectangular solid prior to placing it in the matrix transfer mold PVS used to invest the prototype. The prototype was placed in one half of the matrix transfer mold and the PVS was allowed to cure thus producing half of the matrix transfer mold, Figure 15. Figure 15 (left) Matrix transfer molding process- one half of mold with velar lamina wire positioner and velar lamina. (right) Matrix transfer mold pressed in denture flask press at 1000 psi. The PVS of the completed matrix transfer mold half was then brushed with petroleum jelly and the second half of the denture flask, with yet uncured PVS, was oriented to the first and placed in a denture flask press (Reco Hydromatic, Reco Dental, Wiesbaden, Germany) under 1000 psi pressure to remove air and provide a void free second half of the matrix transfer mold. Upon curing of the PVS the denture flask halves were separated and the prototype removed from the mold. The complete matrix transfer mold consists of the two denture flask halves and the PVS rectangular solid velar lamina wire positioner.

69 VELAR LAMINA- FABRICATION The fabrication of the velar lamina does not involve nor require the maxillary denture base or maxillary impression of the patient. To produce a velar lamina a 95mm section of stainless steel wrought wire (Tru-Chrome Stainless Steel Retainer Clasp Wire- Round inch/18 gauge, Rocky Mountain Orthodontics, Denver, Colorado, USA) is bent into a "U" shape with the terminal ends of the wire 45mm from the bend and the terminal ends spaced approximately 4-5mm apart. The wire is then inserted into the PVS wire positioner and then loaded into the corresponding half of the matrix transfer mold and aligned by means of the orientation groove. The two halves of the mold are lightly brushed with petroleum jelly to provide separation of the mold halves after completion of the silicon curing process. The silicones selected to produce the velar lamina are intended for use as permanent soft lining materials for acrylic dental prostheses, Elite Soft Relining (Zhermack SpA, Badia Polesine, Italy), or as a bite registration material, Memosil 2 (Heraeus Kulzer, Hanau, Germany). Elite Soft Relining is a room-temperature vulcanizing (RTV) type of silicon and is advantageous due to its' resiliency, biocompatibility, antifouling properties, and good dimensional stability. However, negative qualities include: low tear strength, can be attacked by cleansers, and poor abrasion resistance. This silicon may require polishing when used as a soft liner but it can be a laborious process to do so. Heat cured silicones have much longer clinical lifetimes but for this study are less convenient to use due to their processing requirements.[39] Memosil 2 is a transparent addition silicon that is highly accurate, has high dimensional stability, has no disagreeable odor or taste, and is rigid. However, it does possess moderate tear strength which may shorten the life of velar

70 59 lamina. This silicon does not require polishing when used as a bite registration material.[39] The selected silicon, Elite Soft Relining or Memosil 2, is then dispensed around the "U" shaped wire via a static mixer into the half of the mold containing the wire positioner. The opposing half of the mold is oriented to the first and placed in a denture flask press under a pressure of 1000 psi to decrease voids in the silicon of the velar lamina. Once the silicon has cured the mold halves are separated and the velar lamina is removed, Figure 16. The application of pressure produces a very thin film of silicon external to the outline form of the velar lamina that may be trimmed back with Figure 16 (top) Truncate ovate velar lamina after removal from matrix transfer mold. (bottom) Obovate velar lamina after trimming. scissors (Straight/Curved Iris Scissors, Hu-Friedy, Chicago, Illinois, USA) to the intended generic shape, Figure 16. The mold halves are then debrided of any residual silicon and may be further cleaned with isopropyl alcohol to remove any petroleum jelly

71 60 residue. The decision to use a velar lamina made of Memosil 2, Shore A hardness of 72, or Elite Soft Relining, Shore A hardness of 35, was a clinical decision made on a patient by patient basis. In general, velopharyngeal insufficiency patients with larger defects are better addressed with a velar lamina made from Elite Soft Relining material and those with a smaller defect are addressed with a velar lamina made from Memosil 2. Also, velopharyngeal incompetency patients are better served with a velar lamina made from Memosil 2 due to the increased support provided by the stiffer silicon VELAR LAMINA- MODIFICATION The velar lamina begins as a generic object that may be altered with scissors by a prosthodontist or speech pathologist while working alongside a patient. The velar lamina may also be modified with a silicon cutting bur (Finishing Cutter, Zhermack SpA, Badia Polesine, Italy) to round and thereby soften cut edges for improved acceptance by the patient. The velar lamina may be trimmed to simply occupy the midline of the soft palate to function as a desensitization aide for a patient new to wearing a speech prosthesis or it may be trimmed to any outline form determined by the practitioner. Since the velar lamina can be removed from the maxillary denture base it is quite possible to try different outline form configurations at a single patient visit. The wires of the velar lamina are bent outwards, away from the midline, so they diverge prior to being inserted into the retainer tubes. This divergence provides frictional resistance to removal by loading the wires as springs. To insert the velar lamina into the retention tubes it is best to use pliers (Delicate Wire Twister 7 inch, Hu-Friedy, Chicago, Illinois,

72 61 USA) to hold the wires parallel at the same spacing as the distance between the retention tubes and then insert the wires into the retention tubes of the maxillary denture base. When removing a velar lamina it is best to use the same pliers to grasp both of the support wires and withdraw the velar lamina away from the maxillary denture base. The velar lamina may be bent superiorly or inferiorly depending on how it needs to displace the soft palate to close the velopharyngeal sphincter. It is easiest to bend the velar lamina after it has been inserted in the maxillary denture base. Soft tissue conditioner sealers may be used on the silicon of the velar lamina once the proper outline form has been achieved to aid in sealing the material for functional longevity; this procedure was not performed in this study. It is also possible to produce a PVS mold of a trimmed velar lamina to record the outline form so that it may be easily reproduced for future fabrication. The existing velar lamina can be removed from the maxillary denture base and disinfected with an appropriate surface disinfectant. The velar lamina may be properly positioned in either half of the matrix transfer mold. The combined velar lamina and mold is brushed with Vaseline to act as a separating medium and laboratory PVS may be used in an opposing denture flask to produce a mold specific to an individual velar lamina. Once cured the PVS of the unique mold half may be removed from the denture flask and stored with a patients' records. The unique mold half is useful to produce a new velar lamina if an existing velar lamina has deteriorated beyond functional use. From the work done by Vogel, Sauermann, and Ziegler the lifespan of a velar lamina is estimated to be at least 6 months and will most likely fail due to the retention wire perforating the silicon of the velar lamina.[22]

73 TPLP- FABRICATION FOR FULLY OR PARTIALLY DENTATE PATIENT After consent to treatment has been granted, the initial appointment involves making an irreversible hydrocolloid (Jeltrate, Dentsply Canada Ltd., Woodbridge, Ontario, Canada) impression of the patients' maxilla and mandible. The impressions are poured-up in dental stone (Microstone, Whip Mix Corp., Louisville, Kentucky, USA) to produce a maxillary and mandibular stone model of the patient. An impression that extends to the soft palate and velopharyngeal tissues is not required for the fabrication of this style of speech prosthesis, the impression may terminate at or slightly anterior to the vibrating line, Figure 17. In the dental laboratory, the maxillary denture base of the speech prosthesis is produced from the maxillary model. Retention for the maxillary Figure 17 Impression required to fabricate conventional prosthesis. TPLP requires impression limited to hard palate region. denture base is achieved by use of wrought wire clasps that are oriented to maximize retention for the prosthesis. However, if an individual has an existing speech prosthesis then the same teeth retaining the standard prosthesis are selected for clasping the TPLP. Wrought wire clasps are bent from orthodontic wire, (Tru-Chrome

74 63 Stainless Steel Retainer Clasp Wire- Round inch/18 gauge, Rocky Mountain Orthodontics, Denver, Colorado, USA), Rocky Mountain Orthodontics, Denver, Colorado, USA), and oriented on the stone model and held into position with sticky wax (Sticky Wax, Kerr Dental Laboratory Products, Orange, California, USA). Any regions that are heavily undercut so as to prevent the prosthesis from being removed from the model are relieved with an appropriate wax and then separating agent is applied to the palate and teeth of the maxillary model. Orthodontic resin (DP-Ortho pink monomer and DP-Ortho-C orthodontic resin, DenPlus Inc., Longueil, Quebec, Canada) or an equivalent cold cure resin (ProBase Cold Denture Resin- Monomer and ProBase Cold Denture Resin- Polymer(US-L), Ivoclar Vivadent AG, Schaan, Liechtenstein) is applied to the palatal surface of the cast and extended into the palatal embrasures by means of the salt and pepper technique of acrylic addition. The maxillary denture base is fabricated in a similar manner as a standard dental orthodontic retainer. Once sufficient resin has been added the cast is placed in a pneumatic curing unit (Acridense VI, GC America Inc., Alsip, Illinois, USA) with hot tap water under 20 psi pressure and allowed to cure completely. Once cured, the cast is removed from the pneumatic curing unit and the maxillary denture base is separated from the stone cast. The maxillary denture base is roughly trimmed in the areas of the embrasures and any overextension of acrylic is removed to permit the denture to be placed on the model with appropriate retention. If any fracturing occurs to the stone cast the fractured segment is reattached to the master cast by means of cyanoacrylate cement (Permabond 910/Metal Bonding General Purpose, Permabond, Pottstown, Pennsylvania, USA). At the posterior border of the maxillary denture base a trough that

75 64 is approximately 8mm wide and 30mm long is cut into the acrylic of the denture base that falls approximately 1mm shy of penetrating through the full thickness of the base. Within the prepared trough at approximately 2mm to either side of the midline orthodontic tubing (Tru-Chrome Stainless Steel Tubing inch/20 gauge, Rocky Mountain Orthodontics, Denver, Colorado, USA) segments that are 25mm long are placed parallel to one another. The orthodontic tubing segments are positioned from the posterior border of the maxillary denture base and are used to provide the female segment of the retentive attachment for the velar lamina. The orthodontic tubes are occluded at both ends with wax so that they remain patent after they are embedded in acrylic resin. The tubes are tacked into position with cyanoacrylate cement and once stable the same resin used to fabricate the maxillary denture base is added to slightly overfill the midline palatal trough. The cast is then returned to the pneumatic curing unit with hot tap water under 20 psi pressure until completely cured. After the acrylic resin has cured the maxillary denture base is separated from the model and it is trimmed and shaped with standard acrylic burs. The denture base is then polished by fabric wheel and pumice and final polished by hand with pre-polish (SWR22M ET PROVIPRO MED ORANGE PROV POLISHER, Brasseler USA Dental, Savannah, Georgia, USA) and high shine (SWR22F ET PROVIPRO PROV POLISHER, Brasseler USA Dental, Savannah, Georgia, USA) wheels. If the patient requires a maxillary denture base that is a cast metal framework then tooth preparations are performed as required on the appropriate teeth. A final impression is taken with a custom tray using a PVS impression material. The cast framework is fabricated by an external

76 65 professional dental laboratory in the same fashion as a typical partial denture framework TPLP- FABRICATION FOR FULLY EDENTULOUS PATIENT After consent to treatment has been granted the initial appointment involves making an irreversible hydrocolloid impression of the patients' mandible. The impression is poured-up in dental stone to produce a mandibular model of the patient. Since all patients had a sound maxillary speech prosthesis or a complete denture this permitted he fabrication of a mold to duplicate their current prosthesis with laboratory PVS. The mold is comprised of two segments that are indexed to one another to capture the intaglio and cameo surfaces of the prosthesis being duplicated. The first mix of PVS impressed the intaglio surface of the prosthesis with excess PVS extended past the prosthesis to produce a land area surrounding the perimeter of the prosthesis. Once the PVS set, the land area was indexed with three notches and any PVS material that could come into contact with the second addition of PVS was brushed with petroleum jelly as a separating agent. A second mix of PVS was placed over the cameo surface of the prosthesis and extended to the indexed land area previously formed. In the laboratory the mold is used to fabricate a cold cure acrylic (ProBase Cold Denture Resin- Monomer and ProBase Cold Denture Resin- Polymer(US-L), Ivoclar Vivadent AG, Schaan, Liechtenstein) duplicate of the existing palatal lift prosthesis or standard complete denture. Cold cure acrylic is mixed, poured into the mold halves and the halves are approximated and held together with elastics. The complete mold is then

77 66 placed into hot tap water in a pneumatic curing unit at 20 psi pressure and allowed to completely cure. After curing the mold is opened and the duplicate prosthesis is trimmed of burs and the posterior extension, acrylic velar lamina, of the prosthesis reduced to terminate at an approximation of the patients' vibrating line, Figure 18 (far left and left). The teeth of the duplicated prosthesis are trimmed back sufficiently to permit the same mold denture teeth, or similar mold of teeth, to be set on the prosthesis base in wax using the same articulation, Figure 18 (far right). A laboratory PVS jig may be made to aid in establishing the occlusal orientation of the Figure 18 (far left) Cold cure acrylic duplicate maxillary denture base removed from mold. (left) Trimmed duplicate maxillary denture base prepared for retention tubes. (right) Retention tubes imbedded in cold cure acrylic. (far right) Duplicate maxillary denture base with denture teeth added in wax and velar lamina added for try-in with patient prior to final processing. original denture teeth to permit easier transfer of the new teeth. At this point the prosthesis can be tried in the patient at a traditional wax try-in appointment and any occlusal issues can be corrected. Once the occlusion is verified and any esthetic issues are addressed the prosthesis can be flasked and processed. A laboratory PVS model of the intaglio of the duplicated prosthesis is used to process the final prosthesis since a processed base is used. A mixture of plaster and pumice is used to fill the flask after the denture is lubricated with petroleum jelly. Once the plaster and pumice

78 67 mixture has completely set in the flask it is processed with heat cured acrylic resin (Lucitone Original, Dentsply Canada Ltd., Woodbridge, Ontario, Canada) using the recommended curing cycle. After curing is complete the prosthesis is retrieved and finished in the same fashion as a traditional denture except that the palate does not need to be polished at this time. The prosthesis still requires the addition of the female retention tubes, Figure 19, and therefore at the midline of the distal border of the newly Figure 19 (left) Trough cut into maxillary denture base. (middle) Orthodontic tubes occluded with wax at each end tacked to maxillary denture base with cyanoacrylate. (right) Cold cure acrylic resin added to trough via salt and pepper technique. processed prosthesis a trough of approximately 8mm wide by 30mm long is cut into the denture that falls 1-2mm shy of penetrating through the thickness of the acrylic base. Within the trough at approximately 3mm to either side of the midline hollow tubing segments that are 25mm long are placed parallel to one another from the posterior border to provide the female segment of the retentive attachment for the posterior extension. The tubes are occluded at both ends with wax so that they remain patent after they are embedded in acrylic resin. The tubes are held into position with cyanoacrylate cement and once stable cold cure acrylic resin is added via the salt and

79 68 pepper technique to slightly overfill the midline palatal trough. The denture is placed on the laboratory PVS cast used during processing and is then returned to the pneumatic curing unit with hot water under 20 psi unit the acrylic is completely cured. After the acrylic resin has cured the prosthesis is removed from the PVS model and trimmed and shaped with standard acrylic burs. The prosthesis is then polished by fabric wheel and pumice and final polished by hand with pre-polish and high shine wheels.

80 3.0 RESULTS A total of two conventional speech aid/palatal lift prostheses and six TPLP were fabricated for this study since four patients had an existing prosthesis. Of the twelve total prostheses, four had a complete maxillary denture base and eight had a partial maxillary denture base. 3.1 NASOMETRIC ASSESSMENT RESULTS In order to assess the ability of a prosthesis to reduce nasality in speech the Zoo Passage with purely oral sounds was utilized. A normal speaker will achieve a mean nasalance value of 13.45% ±5.94 for the Zoo Passage.[34] All six patients in the study achieved mean nasalance values greater than that of an average normal speaker with Table 3 Mean Nasalance Value(%): Zoo Passage without nasal consonants. Patient 1 TPLP data lost during data transfer. scores ranging from 21-67% when tested without a prosthesis, see Table 3. In general, 69

81 70 the conventional acrylic prosthesis afforded greater nasal reduction than the TPLP. This greater nasal reduction is a benefit to a patient in terms of an increase in speech intelligibility. A Wilcoxon Signed Ranks Test was used to determine if any statistically significant results were obtained from the Zoo Passage recordings. No significant differences were found as illustrated in Table 4. Unfortunately, data was lost for Patient Table 4 Wilcoxon Signed Ranks Test Statistics for the Zoo Passage. 1 for the Zoo Passage due to a data transfer error. The missing data could not be retrieved nor could the test be repeated. The patient was unable to return for speech testing and her TPLP had been converted to a conventional acrylic prosthesis after the patient accidentally broke her existing conventional acrylic prosthesis. The Nasal Sentences are heavily loaded with nasal consonants with 35% of the phonemes comprising the sentences being nasal consonants. This overload of nasal consonants represents more than three times that encountered in standard English.[40] The Nasal Sentences are typically utilized if hyponasality is suspected but may, as is the case in this study, be used to determine if a prosthesis is obstructing the normal production of nasal consonants.[40] A normal speaker will achieve a mean nasalance

82 71 value of 57.90% ±6.69 for the Nasal Sentences.[34] A total of two patients, Patient 4 and 5, had mean nasalance scores greater than two standard deviations, 71.28%, from the normal speaker average and two further patients, Patient 1 and 3, greater than one standard deviation, 64.59%. Generally speaking, Patient 2 and 6, with scores of Table 5 Mean Nasalance Value(%): Nasal Sentences with nasal consonants. 59% and 57% respectively, could be considered within normal speaker limits, see Table 5. The TPLP did tend to decrease nasalance more than the conventional acrylic prosthesis and in one instance, with Patient 1 scoring 48%, may be considered to be obstructing nasal consonant production. However, the general decrease in nasalance from this test may or may not be beneficial to the patient in terms of speech Table 6 Wilcoxon Signed Ranks Test Statistics for the Nasal Sentences.

83 72 intelligibility. When using a Wilcoxon Signed Ranks Test, comparisons were not Bonferroni-adjusted[38], a significant result was obtained when comparing the TPLP to the conventional acrylic prosthesis with an obtained p value of 0.50, see Table SPEECH ACCEPTABILITY ASSESSMENT RESULTS Speech acceptability has been defined as "...the subjective impression of the pleasingness of speech".[41] From speaking with the patients in this study it was simple to determine that the major driving force for patient enrollment in this study was for the potential to achieve better speech acceptability amongst their peers. The data obtained from the speech acceptability evaluation by seven naïve listeners is presented in Table 7. In general, the utilization of either prosthesis improved speech acceptability Table 7 Comparison of Speech Acceptability Results: Patient 1-6.

84 73 for patients. When using a Wilcoxon Signed Ranks Test, a statistically significant result was achieved when comparing speech acceptability without a prosthesis to speech acceptability using the TPLP with a p value of 0.04, see Table 8. However, these Table 8 Wilcoxon Signed Ranks Test Statistics of Speech Acceptability Results. results should not be overstated due to the small population size. The comparison of speech acceptability without a prosthesis to speech acceptability using the conventional acrylic prosthesis, with a p=0.08, and the comparison of the TPLP to the conventional acrylic prosthesis, with a p=0.23, yielded results of no significant difference in perceived speech acceptability between the groups. 3.3 SUBJECTIVE PATIENT FEEDBACK QUESTIONNAIRE RESULTS The subjective patient feedback questionnaire was completed by all patients except Patient 6. For personal reasons that she did not elaborate on, Patient 6 did not wish to answer all questions. The data obtained from the four questions comprising the subjective feedback questionnaire is summarized in Tables 9-12.

85 74 Table 9 Patient Questionnaire: Question 1 results. Table 10 Patient Questionnaire: Question 2 results. Table 11 Patient Questionnaire: Question 3 results. Table 12 Patient Questionnaire: Question 4 Table 13 Comparison of Averages Obtained from the Patient Questionnaire. A review of the data, Table 13, shows that the conventional acrylic prosthesis and the TPLP are assessed by patients as being very similar in terms of how they perceive their speech with a prosthesis, how a prosthesis affects their sensation of gagging or

86 75 choking, and how their speech feels when wearing a prosthesis. However, the conventional acrylic prosthesis was superior to the TPLP, and essentially equivalent to not wearing a prosthesis, when assessing comfort level during swallowing. 3.4 INDIVIDUAL PATIENT RESULTS Since the defect nature and extent of each patient were individually varied, they each provided unique insights how the TPLP would be received. Therefore, a chronological presentation of the observations obtained during fabrication and utilization of the TPLP for each patient follows below PATIENT ONE The first patient presented with velopharyngeal insufficiency, had a partially dentate maxilla and mandible and was in possession of an existing speech prosthesis, Figure 20 (left). The patient benefited from the prosthesis and utilized the prosthesis on a Figure 20 Patient 1: (left) Conventional prosthesis. (middle) TPLP made with acrylic maxillary denture base. (right) TPLP made with cast framework maxillary denture base.

87 76 daily basis. A TPLP with an acrylic maxillary denture base, Figure 20 (middle) and Figure 21 (left), was fabricated for the patient and the immediate feedback given was that the existing cast framework of the contemporary speech prosthesis provided superior retention. In order to permit a fair comparison a cast framework was produced that clasped the same teeth as the existing speech prosthesis, Figure 20 and 21 (right). The retainer tubes were imbedded in an acrylic recess located within the hard palate of the prosthesis. Upon insertion of the TPLP with a cast framework the patient was keenly aware of any contact the velar lamina made with the soft palate and pharyngeal tissues and requested that the extension be reduced. During the modification of the Figure 21 Patient 1: (left) TPLP acrylic maxillary denture base. (right) TPLP cast maxillary denture base. velar lamina for this patient there was a very fine line between the silicon of the velar lamina irritating the tissues to the silicon jabbing the tissues if the velar lamina was over reduced. After modifying several velar lamina to try and obtain an acceptable result for the patient this patient generally found that the acrylic velar lamina was more comfortable than the silicon. The patient did indicate that the acrylic surface of the framework was favored over the existing cast metal framework.

88 PATIENT TWO The second patient presented with velopharyngeal insufficiency, was completely edentulous, had an existing maxillary speech prosthesis and mandibular complete denture, and exhibited highly unintelligible speech, Figure 22. The patient had minimal retention of both prostheses due to the weight and depth of extension of the maxillary speech prosthesis and poor alveolar support for the mandibular complete denture. The patient was not satisfied with either prosthesis and required the addition of denture adhesive applied to the intaglio of the maxillary prosthesis to achieve acceptable retention. The maxillary denture base of the existing speech prosthesis was duplicated to produce a complete denture, Figure 23(left, middle). The complete denture was then converted into a TPLP by addition of the silicon velar lamina. The weight reduction was immediately noticeable by the patient upon first insertion of the TPLP. This patient had a soft palate defect that was quite substantial and consequentially the conventional Figure 22 Patient 2: (top left) Existing soft palate defect. (top right) Existing conventional prosthesis inserted. (bottom) Profile of existing conventional prosthesis.

89 78 prosthesis extended into the defect and flared to engage soft tissue undercuts to aid in retention of the prosthesis. The velar lamina of the TPLP, being devoid of the ability to engage undercuts, has to be oriented to obturate the soft palate defect during function and thus mimic the movements of the soft palate. With the wires of the velar lamina bent to effect some upwards lifting pressure on the soft palate the displacement of the maxillary denture base ensued, Figure 23(right). Even with the addition of denture adhesive the necessary applied pressure of the silicon velar lamina was too excessive to maintain a retentive prosthesis. With a reduction in the applied pressure of the velar lamina the maxillary denture base retention was greatly increased but the obturation effect of the velar lamina was reduced and hypernasality resulted. The patient was Figure 23 Patient 2: (left) Try-in of duplicated maxillary denture base. (middle) Try-in of processed maxillary denture base. (right) Try-in of processed maxillary denture base with velar lamina attached. Notice dislodgement of the anterior of the prosthesis ventrally. able to tolerate and function with both prostheses but in this case the ability of the velar lamina to aide in retention of the conventional prosthesis was a great asset to the patient and was the principal reason the patient preferred the conventional prosthesis to the TPLP.

90 PATIENT THREE The third patient presented with velopharyngeal insufficiency, had a completely edentulous maxilla, and had an existing maxillary speech prosthesis, Figure 24(far left, left). The patient had good retention of the speech prosthesis and after a period of adjustment, approximately 3-4 months, was pleased with the prosthesis and used it on a daily basis. The speech prosthesis greatly reduced hypernasality of speech, thus effecting normal sounding speech and consequently the patient would not be without the prosthesis in a business environment. The maxillary denture base of the existing speech prosthesis was duplicated to produce a complete denture. The complete denture was then converted into a TPLP by addition of the silicon velar lamina, Figure 24(right). Unlike patient two the soft palate defect was far more conservative and the Figure 24 Patient 3: (far left) Existing soft palate defect. (left) Existing conventional prosthesis inserted. (right) TPLP with velar lamina of lesser durometer inserted. (far right) TPLP with velar lamina of higher durometer inserted. acrylic velar lamina of the conventional prosthesis did not contribute substantially to retention of the prosthesis. Since the patient also had ideal anatomical morphology to retain a complete denture prosthesis the applied pressure of the TPLP velar lamina was not a negative factor with this patient. Interestingly, upon insertion of the silicon velar lamina made from lesser durometer Elite Soft Relining material the patient was

91 80 very aware, almost hypersensitive, to the periphery of the silicon velar lamina. The resultant clinical response was to reduce the outline form in the region of the irritation to remove the offending material. Inevitably the velar lamina was over-reduced and hypernasality ensued due to inadequate obturation of the defect. The patient made the statement that they felt the hard acrylic of the conventional prosthesis substantially less than the soft silicon and this was a surprise to the patient. Two alterations resulted from observations and interactions with this patient. Firstly, a second silicon, Memosil 2, with a higher durometer, Shore A hardness of 72 compared to 35, was selected to produce velar lamina. Secondly, a new outline form with a less tapered periphery, a truncate ovate morphology, was designed and a matrix mould produced to fabricate the Figure 25 Truncate ovate velar lamina outline form in lesser durometer silicon. corresponding velar lamina, Figure 25. The new velar lamina was inserted into the same maxillary denture base and after modification with scissors and a silicon cutting bur the patient found the new harder silicon velar lamina to be undetectable, even less noticeable than the conventional acrylic prosthesis, Figure 24 (far right). The patient found that during function both prostheses reduced hypernasality with the TPLP not

92 81 quite as effective as the conventional prosthesis. The patient commented that if the conventional prosthesis was inserted in the morning there were no issues with gagging but if the TPLP was inserted in the morning gagging occurred. The patient initially had issues with gagging with the conventional prosthesis that subsided after 3-4 months of use. The patient found both prostheses comfortable to wear and used the conventional prosthesis all day during work and transferred to the TPLP at home during the evening because it was lighter and less intrusive since it did not project into the defect. The patient stated that when the TPLP was used it felt like it gave the tissues a rest PATIENT FOUR The fourth patient presented with velopharyngeal insufficiency, was fully dentate, and had an existing maxillary speech prosthesis. The patient had compromised retention of the existing speech prosthesis due to the weight and depth of extension of the speech prosthesis even though teeth were available for clasping. The patient used the prosthesis in social settings but was not completely satisfied with the prosthesis due to Figure 26 Patient 4: (left) Conventional prosthesis. (right) TPLP.

93 82 its' posterior weight and slight rocking during function. The existing speech prosthesis had a maxillary denture base and velar lamina fabricated from acrylic resin with wrought wire clasps added for retention, Figure 26(left). The maxillary denture base for the TPLP was fabricated from a maxillary irreversible hydrocolloid impression and was clasped in the same fashion as the existing prosthesis, Figure 26(right). Upon insertion of the TPLP the patient immediately noticed the decrease in prosthesis weight and corresponding increased retention. For this patient the velar lamina did not require any modification since the patient found it comfortable, Figure 27. From first insertion the patient favored the TPLP and started using it in the same social settings as the Figure 27 Patient 4: (left) Existing soft palate defect. (right) TPLP with velar lamina of lesser durometer inserted. conventional prosthesis had been used. The patient did not suffer from any soft tissue trauma or irritation with continued use, over 3 months, and the silicon did not demonstrate any deterioration during the time it was worn. The patient favored the TPLP in this case due to the weight reduction and enhanced retention the TPLP afforded.

94 PATIENT FIVE The fifth patient presented with velopharyngeal incompetency that also affected some members of his or her immediate family. The patient was fully dentate and had an existing maxillary speech prosthesis but the speech prosthesis had not been worn for approximately 5 years due to fractured cast clasps that caused rocking of the prosthesis during function, Figure 28(far left). Therefore, both a conventional and TPLP was required for this patient, Figure 28(right, far right). Since the patient presented with a speech prosthesis that incorporated a cast framework for the maxillary denture base a cast framework was selected for the maxillary denture base of both prostheses to be fabricated. The patient already had tooth preparations for the cast Figure 28 Patient 5: (far left) Existing conventional prosthesis. (left) New conventional prosthesis with partial velar lamina. (right) New conventional prosthesis with complete velar lamina. (far right) TPLP. framework and although not ideal the patient did not want any enhancement of the existing preparations. The patient indicated that during the previous prosthesis fabrication his or her strong gag reflex required that the velar lamina be incrementally extended over several appointments to permit adaptation to the prosthesis. During the final impression for the fabrication of the maxillary denture base the patient had a very difficult time even without extension of the impression material into the soft palate region. The master cast was duplicated so that two cast frameworks could be made for

95 84 the conventional and TPLP. Since a soft palate defect was not present and the velar lamina of the previous prosthesis was intact and had been previously used successfully by the patient it was decided to copy the existing velar lamina and transfer that morphology to the new cast framework, incrementally in stages, for the production of the conventional prosthesis. Since the patient had such a strong gag reflex and had not utilized a prosthesis for over 5 years the patient was initially permitted to only wear the maxillary denture base cast framework without a velar lamina and even this Figure 29 Patient 5: (upper) Velar lamina of conventional prosthesis modified to morphology of previous prosthesis by salt-and-pepper addition of cold cure acrylic. (middle) Profile of velar lamina of previous prosthesis. (bottom) Profile of velar lamina of new prosthesis. challenged the gag reflex of the patient. Once the maxillary denture base was tolerated the patient requested that a very small velar lamina be added to the framework. The

96 85 framework for the conventional prosthesis was selected, due to previous exposure to the patient, and was placed on the stone mold produced of the original velar lamina to extend the acrylic approximately 20mm distally, Figure 28(left). Upon insertion this modification was tolerated for mere seconds but the patient felt with practice and time it would be tolerable. By the next appointment the prosthesis could be worn with minimal gag response throughout the day. The only modification was a midline reduction to the velar lamina at the union with the cast framework which was causing tissue irritation. A TPLP with a velar lamina that extended to a similar extent distally as the previously worn prosthesis was also delivered to the patient, Figure 28(far right). Once again the patient was unable to tolerate the new prosthesis but thought that with practice and time it would be tolerable. At the next appointment the patient was able to tolerate both prostheses so the conventional prosthesis was modified to have a full contour velar lamina that approximated the velar lamina of the previously worn prosthesis, Figure 29(upper, lower). Once again on initial insertion of the modified prosthesis the patient had gagging issues but was again given time to adapt. Due to the generic nature of the velar lamina of the TPLP no further addition to the velar lamina was possible to aide in displacing the soft palate superiorly so the prosthesis was considered finalized. After the patient adapted to the prostheses they commented that since they had worn a prosthesis previously they liked the feel of the polished acrylic more than the silicon but the lighter silicon seemed to cause less disengaging of the maxillary denture base which was positive.

97 PATIENT SIX The sixth patient presented with velopharyngeal incompetency, was fully dentate and had never worn an oral prosthesis, Figure 30(left). This patient had highly unintelligible speech and was extremely motivated to seek treatment that would aide in any improvement in his or her speech. This patient required the fabrication of both a conventional and TPLP, Figure 30(middle, right). The patient was able to tolerate without any inconvenience a standard alginate impression of the dentate maxilla required to fabricate the TPLP. However, with a standard maxillary impression tray extended with wax angled distally and superiorly to impress a slightly elevated soft Figure 30 Patient 6: (left) Existing soft palate anatomy. (middle) Existing conventional prosthesis inserted. (right) TPLP with velar lamina of greater durometer inserted. palate the patient exhibited gagging that required the repetition of the impression to achieve an acceptable result. The patient commented that they did not like the soft palate impression process and did not want to have to go thought that experience again. An acrylic maxillary denture base with wrought wire clasps was fabricated for both prostheses and the patient was given the TPLP without a velar lamina for use in adjusting to wearing a prosthesis. After one week the patient felt comfortable wearing

98 87 the maxillary denture base and at the next appointment was presented with both the conventional prosthesis and the TPLP. The velar lamina of the conventional prosthesis was reduced as directed by the patient but the patient still felt awkward wearing the prosthesis due to the presence of the velar lamina. The TPLP was fabricated with less clasping than the conventional prosthesis and was retained to permit the addition of clasps to equal the retention of the conventional prosthesis. After one week of adapting to the conventional prosthesis the patient required some minimal reduction of the velar lamina to find it acceptable. The TPLP was inserted and the velar lamina shaped as per patient feedback. This patient found the TPLP to be comfortable since the velar lamina was softer than the acrylic counterpart of the conventional prosthesis. The patient was given two weeks to use the prostheses and upon return commented that no further irritation from the prostheses existed but that they are still becoming accustom to wearing a prosthesis throughout the day in general. After a further week Figure 31 Patient 6: (left) Conventional prosthesis. (right) TPLP. of usage the patient did favor the TPLP even though it had a larger velar lamina due to it being more comfortable to wear but the patient was unsure if there was enough

99 88 improvement in speech intelligibility gained from wearing the prosthesis to warrant using a prosthesis, Figure 31(left, right).

100 4.0 DISCUSSION In order to assess the TPLP relative to the conventional palatal lift prosthesis, a comparison based on patient type, velopharyngeal insufficiency versus velopharyngeal incompetency, an analysis of the characteristics of the velar lamina of both prostheses, and potential uses for the TPLP is discussed. 4.1 VELOPHARYNGEAL INSUFFICIENCY PATIENT If the TPLP is being made for a patient suffering from velopharyngeal insufficiency the periphery of the velar lamina is required to apply pressure to the soft tissues throughout the range of function to affect a division between the oral and nasal cavities. Conversely, a conventional prosthesis may have a velar lamina that enters the defect and projects superiorly that permits the tissue borders of the defect to elevate and depress during function and thereby maintain contact with the prosthesis to separate the nasal and oral cavities. Since the TPLP velar lamina does not enter the soft tissue defect the separation of the oral and nasal cavities are produced from the velar lamina slightly overlapping the borders of the defect and maintaining contact with the soft tissues. This requires that the TPLP velar lamina be oriented so that it applies a force towards the soft tissue much like the action of a spring. This springing action places an opposing force on the maxillary denture base to displace it away from the supporting tissues. Therefore the TPLP requires greater maxillary denture base retention to counteract the forces of the velar lamina. Furthermore, it is advantageous if the velar 89

101 90 lamina of a conventional prosthesis enters the defect as an acrylic bulb that engages soft tissue undercuts which can increase retention of the prosthesis. Since the TPLP velar lamina remains external to the defect it cannot take advantage of this potential increase in retention. Therefore, for velopharyngeal insufficiency patients that require a TPLP it would be advisable that as the size of the soft tissue defect increases the maxillary denture base retention should increase proportionately. A patient with a large defect is better served by a maxillary denture base that is tooth supported, as is demonstrated with Patient 4, and a patient with a small defect may have a well fabricated complete denture as their maxillary denture base, as is demonstrated with Patient Three. Therefore, fabrication of a TPLP with a CUD as the maxillary denture base may be contraindicated unless the defect is relatively small due to the fact that the velar lamina does not enter the defect and applies a positive pressure to the tissues surrounding the defect. The decision to use a velar lamina that simply covers, like the TPLP, or extends into the defect, as the conventional prosthesis typically does, is a patient by patient decision that is made chairside by the clinician. From clinical interaction with velopharyngeal insufficiency patients when fabricating a TPLP for a patient it became apparent that there is an inverse relationship between the size of the defect and the durometer of silicon appropriate to fabricate the velar lamina. A larger defect requires that the silicon be able to flex and drape with the contours of the soft palate as seen with Patient 4 versus a more conservative defect where a harder silicon may be preferred as seen with Patient 3.

102 VELOPHARYNGEAL INCOMPETENCY PATIENT If the palatal lift prosthesis is being made for an individual with velopharyngeal incompetence then the primary function of the velar lamina is to elevate the intact soft palate into an appropriate orientation to produce velopharyngeal port closure. The generic velar lamina produced for the TPLP may achieve an acceptable result if distal elevation of the soft palate directly along the midline is required. The tapering of the velar lamina at the periphery is not required and is in fact more likely to require removal since it is too thin to be supportive of any elevation and therefore provides unnecessary bulk in the oropharyngeal space. If the soft palate requires elevation closer to the lateral pharyngeal walls the width of the present generic velar lamina may not suffice and may require the design to be increased in width or have a selection of sizes, perhaps small, medium and large, of generic velar lamina. The length of the velar lamina required to lift the soft palate may be shortened by removing the silicon closest to the maxillary denture base and reducing the supporting wires. If the velar lamina is too short then a longer analog may need to be fabricated. If the individual does not require elevation of the soft palate at the lateral pharyngeal walls bilaterally then the reduced generic velar lamina may provide more material on the unaffected side than the conventional acrylic velar lamina and be invasive to the patient. 4.3 VELAR LAMINA The velar lamina of the TPLP is fabricated from a generic mold and consequently the midline is of a consistent thickness to embed the retention wire. The thickness should

103 92 be maintained to prevent the wire from perforating the silicon and rendering the velar lamina non-functional. However, it is possible to produce from acrylic resin a velar lamina with a thinner profile extending along the midline. Since acrylic resin is stronger in a thinner layer than silicon it may be the material of choice if a patient finds that the morphology of the velar lamina along the midline is too bulky during function. The velar lamina of a conventional prosthesis is fabricated from acrylic. Acrylic is advantageous to silicon in terms of ease of modification and ability to receive a high polish. If the velar lamina of a TPLP is over-reduced it is advisable to reshape a new velar lamina rather than adding to the over-reduced one. Conversely, a velar lamina produced from acrylic may be modified via standard laboratory procedures which would be preferable to fabricating a new acrylic velar lamina. The surface finish of processed acrylic may be polished to a smoother surface than that of the silicon of the TPLP velar lamina. Some patients do favor the high polish achievable with acrylic and this may help indicate which style of prosthesis is suitable for a patient. However, even though patients were able to distinguish that, in general, acrylic was smoother than silicon the soft tissue ulcerations that developed from prosthesis use were due to acrylic or cast metal prosthesis components and not the silicon velar lamina. The TPLP feature of having a removable velar lamina is a nice option when working with the patient clinically during fabrication and modification appointments. However, if a patient is to function long term with the prosthesis then retention of the velar lamina

104 93 becomes an issue. All patients in this study did raise concerns over the potential loss of the velar lamina during function. This is a valid concern and it is recommended that once a prosthesis is finalized that the velar lamina be united to the maxillary denture base by cyanoacrylate cement and cold cure acrylic. If a prosthesis is required to be used by a patient when interacting with a speech pathologist then a duplicate maxillary denture base can be fabricated and velar lamina interchanged with the duplicate prosthesis. Trimming the silicon velar lamina of the TPLP to a morphology that will function as desired is not necessarily an easy task. It is easy to cut silicon with scissors but judging how much to cut and the exact location to cut involves weighting the input received from a clinical examination, the patient feedback given and in some instances an "educated guess" by the clinician. For example, it is ideal for the velar lamina fabricated for velopharyngeal insufficiency patients to have a periphery that remains as extended as possible to cover and overlap the defect during the full range of function. However, as the defect reduces in size the patients' sensation in the tissues surrounding the defect generally tends to increase and the patients' desire to reduce the overlapping silicon margin is greater. As the marginal overlap decreases the risk of a communication between the oral and nasal cavities increases. Unfortunately only a small reduction of silicon may convert a viable prosthesis into a situation where the procedure needs to be repeated with a new velar lamina. This issue would suggest that it is better to err on less reduction of the velar lamina and give more time for patient

105 94 adaptation to the TPLP or start with a smaller less functional velar lamina and increase to an acceptable velar lamina as adaptation permits. 4.4 POTENTIAL USES The greatest benefit of the TPLP is the ability to produce a palatal lift prosthesis for a dentate patient from a simple alginate impression of the maxillary hard palate region. A TPLP can be delivered to a dentate patient on his or her subsequent appointment after the maxillary impression has been made. If a patient is edentulous then the fabrication of the maxillary denture base requires standard complete denture fabrication protocol and becomes a lengthier process. Dentate patients new to a speech prosthesis may benefit from the ability to receive a maxillary denture base at their second clinical appointment. During that same appointment they can try-in a velar lamina to experience their response to a prosthesis extending into the soft palate region. The velar lamina can be reduced to permit adaptation by a patient to a prosthesis and the velar lamina can be increased at subsequent appointments to produce a stepwise adaptation to the prosthesis by the patient. Patients that have an existing speech prosthesis probably do not require this approach as they have already been desensitized in the soft palate region. A conventional speech prosthesis produced from acrylic may also be adapted in a similar stepwise fashion but the laboratory work required to increase the velar lamina would typically preclude same day delivery of the prosthesis, although it is possible to deliver a modified acrylic prosthesis the same day.

106 95 Also, there would probably be fewer overall modification steps since it is more laborious to modify the acrylic velar lamina. If a speech prosthesis is to be made for a patient that has not had exposure to a removable dental prosthesis and there is question as to the patients' ability to accept a removable prosthesis, for example a child, the TPLP may be a very good initial exposure to "test the waters". The fabrication cost but more importantly clinical time required to produce the prosthesis makes the TPLP a less expensive trial prosthesis for the patient. The TPLP may also be converted to a conventional prosthesis if it is determined that a patient would benefit from an acrylic velar lamina. The silicon velar lamina may be used with appropriate impression adhesive and polyvinylsiloxane impression material to impress the soft palate and from the produced model be converted to acrylic. During the velar lamina conversion the retention wire may be affixed to the retention tubes and the acrylic of the maxillary denture base extended and united to the velar lamina to produce a solid union. A patient requiring a speech prosthesis pre- and post-surgical soft palate modification, for example cleft palate patients, may benefit from the quick adaptation of the velar lamina the TPLP affords. Although not clinically demonstrated in this study the generic velar lamina may be modified to a more custom silicon velar lamina. A wash of the same silicon liner may

107 96 be added to the existing velar lamina with adhesive applied to produce a functionally generated velar lamina.

108 5.0 CONCLUSION The primary objective of this study was to determine if a generic velar lamina made from silicon could be tolerated by a patient and function to reduce hypernasality. With the present design of the TPLP there were instances where the prosthesis was applied and resulted in a functional reduction of hypernasality. The TPLP did not provide superior results compared to the conventional acrylic palatal lift prosthesis and generally reduced hypernasality to a lesser degree. One patient did prefer the TPLP and still uses the prosthesis due to the reduction in weight afforded by the TPLP construction. The nasalance values obtained from this patient were almost identical to the values obtained with the conventional prosthesis so the decision to use the TPLP was made based on patient comfort. However, it was generally seen that the conventional palatal lift prosthesis was more widely accepted by velopharyngeal incompetency and velopharyngeal insufficiency patients. The removable connection used to make the TPLP modular was functional when working alongside a patient and did permit the utilization of velar lamina with differing outline forms on a single patient. Patients did function with the velar lamina attached to the maxillary denture base only by means of the friction within the connection. However, for peace of mind for the patient and the provider, the decision to provide a rigid connection once a velar lamina was contoured to its' final shape was made. The larger the velar lamina the greater the chance the tongue could provide a distal, and 97

109 98 dislodging, movement and effect to work the velar lamina away from the maxillary denture base. Therefore, the TPLP can remain modular during the fabrication process but once finalized the modularity is lost as it is converted into a permanent prosthesis. The conventional acrylic prosthesis and the TPLP are assessed by patients as being very similar in terms of how they perceive their speech with a prosthesis, how a prosthesis affects their sensation of gagging or choking, and how their speech feels when wearing a prosthesis. However, the conventional acrylic prosthesis was superior to the TPLP, and essentially equivalent to not wearing a prosthesis, when assessing comfort level when swallowing with a prosthesis. In general, the conventional acrylic prosthesis afforded greater nasal reduction when testing a passage without nasal consonants, the zoo passage, than the TPLP. This greater nasal reduction is a benefit to the patient in terms of an increase in speech intelligibility. Conversely, when testing sentences with nasal consonants, the Nasal Sentences, the TPLP did decrease nasalance more than the conventional acrylic prosthesis which may or may not be beneficial to the patient. In general, the utilization of either prosthesis improved speech acceptability for patients. Within the limitations of this study, statistically significant results were seen when comparing speech acceptability without a prosthesis to speech acceptability

110 99 when using the TPLP, p=0.04, and when comparing speech acceptability without a prosthesis to speech acceptability when using the conventional acrylic prosthesis, p=0.08. However, these results need not be overstated due to the small population size. It is expected that the knowledge gained in this study and the prosthesis design may be further modified for use to combat hypernasality and may be applicable for use with other communication disorders.

111 REFERENCES 1. Perry, J.L., Anatomy and Physiology of the Velopharyngeal Mechanism. Seminars in Speech and Language, (2): p The Glossary of Prosthodontic Terms. The Journal of Prosthetic Dentistry, (1): p Anandakrishna, G.N. and S. Gali, Management of velopharyngeal disorders. A case series. Journal of Prosthodontics : Official Journal of the American College of Prosthodontists, (5): p Gray, H., Anatomy, Descriptive and Surgical, 1859, Blanchard and Lea: Philadelphia. p Kummer, A.W., Types and causes of velopharyngeal dysfunction. Seminars in speech and language, (2): p Mazaheri, M. and E.H. Mazaheri, Prosthodontic aspects of palatal elevation and palatopharyngeal stimulation. The Journal of Prosthetic Dentistry, (3): p Ramsey, W.O., Terminology applicable to palatal lift prostheses. The Journal of Prosthetic Dentistry, (5): p Gibbons, P. and H. Bloomer, A supportive-type prosthetic speech aid. The Journal of Prosthetic Dentistry, (2): p Aram, A. and J.D. Subtelny, Velopharyngeal function and cleft palate prostheses. The Journal of Prosthetic Dentistry, (1): p Aramany, M.A., A History of Prosthetic Management of Cleft Palate: Pare to Suersen. Cleft Palate Journal, (4): p Fox, J., Of Artificial Obturations and Palates., in The Natural History and Diseases of the Human Teeth, C.A. Harris, Editor 1846, Ed. Barrington and Geo. D. Haswell: Philadelphia. p Kingsley, N.W., Part II. Palatine Defects, in A Treatise on Oral Deformities as a Branch of Mechanical Surgery1880, D. Appleton and Company: New York. p Richardson, J., Defects of the Palate Organs and their Treatment by Artificial Means, in A Practical Treatise on Mechanical Dentistry1886, P. Blakiston, Son & Co.: Philadelphia. p Balber, G., Cleft palate prosthesis without surgical redivision. The Journal of Prosthetic Dentistry, (3). 15. Beder, O.E., J.A. Carrell, and J. Tomlinson, The palatal elevator button. The Journal of Prosthetic Dentistry, (2). 16. Gonzalez, J.B. and A.E. Aronson, Palatal lift prosthesis for treatment of anatomic and neurologic palatopharyngeal insufficiency. The Cleft Palate Journal, : p

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113 Bressmann, T., Comparison of nasalance scores obtained with Nasometer, the NasalView, and the OroNasal System. Cleft Palate Craniofacial Journal, : p Bressmann, T., P. Klaiman, and S. Fischbach, Same noses, different nasalance scores: Data from normal subjects and cleft palate speakers for three systems for nasalance analysis. Clinical Linguistics and Phonetics, : p Hodge, M. and C.L. Gotzke, Preliminary results of an intelligibility measure for English-speaking children with cleft palate. Cleft Palate Craniofacial Journal, : p Bressmann, T., et al., Quantitative 3D ultrasound imaging of partially resected tongues. Otolaryngology-Head and Neck Surgery, : p Bressmann, T. and J. Beitchman, Communication disorder not otherwise specified: Voice, in Comprehensive Textbook of Psychiatry, B.J. Sadock and V.A. Sadock, Editors. 2009, Lippincott, Williams & Wilkins: New York. p Pernerger, T.V., What's wrong with Bonferroni adjustments. British Medical Journal, (7139): p O'Brien, W.J., Polymers and Polymerization, Impression Materials, in Dental Materials and Their Selection, W.J. O'Brien, Editor 2002, Quintessence Publishing Co., Inc.: Hanover Park, Il. p Kummer, A.W., Cleft Palate & Craniofacial Anomalies: Effects on Speech and Resonance. 2 ed2008: Delmar Publishers Inc Witzel, M.A., Communicative impairment associated with clefting, in Cleft palate speech management: A multidisciplinary approach, R.J.S.J. Bardach, Editor 1995, Mosby: St. Louis, MO. p

114 APPENDICES APPENDIX 1: TREATMENT MODALITY SELECTION BY WOLFAARDT.[21] COPYRIGHT 1993, ELSEVIER. 103

115 APPENDIX 2: NOTIFICATION OF REB INITIAL APPROVAL 104

116 105 APPENDIX 3: CARING FOR YOUR TORONTO PALATAL LIFT PROSTHESIS Caring for Your Toronto Palatal Lift Prosthesis For safety reasons, the prosthesis should not be worn while eating, during vigorous physical exercise or while sleeping. The TPLP can be rinsed between wears and should be cleaned daily (in the evening before bed). The TPLP can be cleaned with a denture brush or toothbrush using a commercial denture cleaning agent (foam, liquid or tablet) or liquid hand soap and water. Rinse the prosthesis thoroughly. Do not use toothpaste as it is abrasive and encourages scuffing of the polished acrylic and may help to tear the silicon. Clean both the acrylic retainer and the silicon flap as follows: Step 1 Clean the both sides of the acrylic retainer. Step 2 Position the flap portion over a sturdy surface.

117 106 Step 3 - Hold the flap steady without straining the attachment to the retainer portion. Step 4 - Brush the surface from the centre to the edges. Step 5 - Turn over prosthesis and repeat.