Reliability of pterygomaxillary notch in determination of width of maxillary anterior in Indian and Malaysian population

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Research Article Reliability of pterygomaxillary notch in determination of width of maxillary anterior in Indian and Malaysian population Chandini Ravikumar, Ashish R.

1 Research Article Reliability of pterygomaxillary notch in determination of width of maxillary anterior in Indian and Malaysian population Chandini Ravikumar, Ashish R. Jain* ABSTRACT Background: Compared to other intraoral landmarks, pterygomaxillary notch (PMN) is a highly significant structure, as it can be easily identified on the casts and not subject to any soft tissue changes. With regard to choosing the dentate casts, it is justified that the measurements from artificial teeth may be misleading when compared to the natural teeth. Therefore, dentate casts are considered as the better option in measuring the width of maxillary anterior. Aim: The main objective of this study is to determine the width of maxillary anterior in dentate casts of Indian and Malaysian population, using PMN as the anatomical landmark. Materials and methods: The study comprises 17 Indian and 17 Malaysian population of years of age with Angle s Class 1 maxillomandibular relationship. The exclusion criteria are patients with carious lesions, periodontal problems, edentulous spaces, history of orthodontic treatment, malocclusion, and other congenital dental defects. Impression was made using irreversible hydrocolloid impression material. Casts were obtained after pouring the impression with hard setting dental stone. The six anterior tooth width measurements from each of the casts were summed up to give a total width of maxillary anterior on each cast. The distance between the PMN was measured using a Vernier Caliper to determine its correlation with the width of maxillary anterior. The level of significance was established at α = 0.01 for Indian population and α = 0.05 for Malaysian population. Results: The mean mesiodistal width of the six maxillary anterior teeth was mm, and the mean distance of the inter PMN was mm in Indian population. In the Malaysian population, the mean mesiodistal width of maxillary anterior teeth was mm, and the mean distance of the inter PMN was mm. There was a statistically significant positive correlation between the inter PMN distance and total mesiodistal width of the six maxillary anterior teeth. Conclusion: It is concluded that the PMN can be used as a putative guide in determining the width of maxillary anterior, irrespective of different group populations. However, further research is recommended in this field, to establish a method that is universally accepted in maxillary anterior width measurement. KEY WORDS: Pterygomaxillary notch, Maxillary anterior, Indian, Malaysian population INTRODUCTION Function and esthetics must be restored while managing a completely edentulous patient. The anterior teeth are primarily selected to satisfy and establish perfect esthetics. The selection requires comprehensive knowledge and artistic skill of the dentist. Teeth that are of proper size are essential in achieving a natural looking denture. Patients requiring complete dentures usually expect comfort first, followed by harmonious appearance and efficiency. Besides, on receiving their Access this article online Website: jprsolutions.info ISSN: first dentures, patients often expect to appear similar to when they had their natural teeth. Therefore, correct selection of artificial teeth is essential to achieve a pleasant esthetic outcome. The width of the maxillary anterior is difficult to correlate with the facial measurements than the height of the maxillary anterior. In addition, the generation approaching 70 years of age recognizes that maintaining their natural dentition improves appearance and smile and serves as a visible sign of successful aging. Many efforts have been made to accurately quantify the selection of the anterior teeth. Some of the more familiar ones are bizygomatic width (BW), interpupillary distance (IPD), intercanthal distance (ICD), interalar width (IAD), and intercommisural width, and some newer Department of Prosthodontics, Saveetha Dental College and Hospital, Saveetha University, Chennai, Tamil Nadu, India *Corresponding author: Dr. Ashish R. Jain, Department of Prosthodontics, Saveetha Dental College and Hospital, Saveetha University, 162 Poonamallee High Road, Chennai , Tamil Nadu, India. Phone: dr.ashishjain_r@yahoo.com Received on: ; Revised on: ; Accepted on:

2 anatomical measurements, such as philtral width, pterygomaxillary notch (PMN), circumference of skull, maxillary arch length, and maxillary arch width, have also been studied. However, little agreement on an effective method has been reached. There is no consensus of data regarding a single esthetic factor that can be used reliably as an aid for artificial tooth selection. [1] In the process of complete denture fabrication in edentulous patients, it is imperative to consider tooth selection as a crucial factor as it aids in restoring facial appearance and enhancing function. To establish harmonious dentition, size, form, color, arrangement, and framing of the teeth should be brought together in accordance. [2] In most cases, the artificial teeth are smaller and whiter than natural teeth. In choosing the tooth size, mesiodistal width is more important than the crown length. Indentures, the mesiodistal width of the anterior teeth is the most important factor, because complete dentures will not be able to provide a real appearance, occlusion and function if artificial teeth are too small. The dentogenic concept or the SPA (sex, personality, and age) factor, introduced by Frush and Fisher, plays an essential role in anterior teeth selection. [3] Over the past few years in the field of dentistry, smile designing has emphasized on esthetics for edentulous patients, and the selection of artificial anterior teeth has become an established requirement as far as esthetics is concerned during the fabrication of complete dentures. [4] In general, the clinician s choice in selecting the appropriate width of maxillary anterior teeth is inclined toward the facial proportions or arch measurements. A number of soft tissue extraoral facial landmarks are indicated for anterior teeth selection including the BW, IPD, IAD, ICD, sagittal cranial diameter, interbuccal frenum distance, philtrum width, and intercommissural width, whereas the intraoral landmarks include the incisive papillae, palatine fovea, arch width from mesiopalatal (MP) cusp tips of molar teeth, intercanine width, palatal width, and the hamular notch. [5] The main setback in performing biometric measurements is the inaccurate static relationship of soft structures, as the width of soft tissues may change visibly, as attributed to factors such as age, weight, and built of the person. Therefore, attempts have been made to establish a relationship between the dimensions of anterior teeth with intraoral anatomical landmarks which are a highly challenging task. [6] Many authors have emphasized the difficulty of choosing suitable replacement teeth for edentulous patients and arranging these teeth in a natural way. Error in this stage often leads to rejection of otherwise well-made, comfortable and efficient teeth. Therefore, one of the most important considerations in prosthetic treatments is to make dentures with good appearance. To overcome the errors obtained from soft tissue landmarks, inter PMN distance is chosen to be a reliable method for measuring the anterior teeth. The PMN, also known as the hamular notch, is a palpable landmark of the palate formed by the junction of the maxilla and the pterygoid hamulus of the sphenoid bone. The pterygomandibular ligament is attached to the hamulus of the medial pterygoid plate. The hamular notch is about 2 mm wide that contains loose connective tissue and covered by mucosa of adequate thickness. It is a depression that is situated distally to the maxillary tuberosity, and primarily used to determine the posterior border of the maxillary denture. The PN is a displaceable area and can be compressed to achieve good peripheral seal. It is not exposed to any changes due to age or weight factors and is easily identified on dental casts. Various authors have suggested inter PMN distance as a putative guide in artificial tooth selection. [7] The primary purpose of this study is to determine the width of maxillary anterior in dentate casts by using PMN as the anatomical landmark. It has been documented in studies that the artificial anterior teeth are not natural as required and may not perfectly simulate the life-like appearance. Moreover, the measurements from artificial teeth may be misleading with regard to the size of the prosthetic molds when compared to the natural teeth. Due to the inaccurate measurements are given by artificial teeth, it is, therefore, suggested that dentate casts be considered as the better option in measuring the width of maxillary anterior. [8] There is a constant search made by investigators to find the efficient method of determining the width of maxillary anterior. In the current scenario, there is no universally accepted method for artificial tooth selection, and further research is recommended in this field. MATERIALS AND METHODS The study comprises Indian and Malaysian population of years of age with the following inclusion and exclusion criteria: Inclusion Criteria A total of 34 dentate subjects (17 Indian and 17 Malaysian) in the age group years, with Angle s Class 1 maxillomandibular relationship and natural maxillary teeth in the good alignment were selected for the study. Exclusion Criteria The following criteria were excluded from the study: Patients with a history of orthodontic treatment. Patients with malocclusion. Patients with periodontal disease. Patients with carious lesions. Patients with extensive direct and indirect restorations. Patients with edentulous spaces. Patients with congenital dental defects. 526

3 Methodology A total of 34 subjects (17 Indian and 17 Malaysian) in the age group of years were selected for the study. Perforated metal stock tray of suitable sizes was selected for each of them. Impression was made using irreversible hydrocolloid impression material. Casts were obtained after pouring the impression with hard setting dental stone. Powder to liquid ratios for the alginate and stone materials were measured following manufacturer s instructions, and stone casts were allowed to set. The casts were then separated from the alginate impressions and trimmed. Measurements were initiated with individual width and length of all maxillary anterior teeth using the caliper tips at the highest and widest dimensions of each tooth on each cast. Furthermore, the combined width of maxillary anterior teeth was measured from the distal convexity of upper right canine to the distal convexity of the contralateral canine using markings on clear celluloid strips. The hamular notches were marked on both sides, and the distance between them was measured, and 10 mm was added. The six individual anterior tooth width measurements from each of the casts were summed up to give a total width for the six anterior teeth on each cast. The distance between the PMN was measured using a Vernier Caliper to determine its correlation with the width of maxillary anterior. The measurements were recorded in mm. The procedure was performed in 17 Indian and 17 Malaysian patients. Normality distribution was checked and the Pearson correlation test was done to determine the relationship between total width of anterior teeth and the inter PMN distance. t-test was done to compare the widths of maxillary anterior and interpterygomaxillary notch distance between the two groups, Indian and Malaysian population. The level of significance was established at α = 0.01 for Indian population and α = 0.05 for Malaysian population. Sample size calculation is given in Figure 1. of combined width of maxillary anterior in Indian and Malaysian population is depicted. Figure 4 shows the mean, standard deviation, and standard error mean of IPN distance and width of maxillary anterior in Indian population. Figure 5 depicts the mean, standard deviation, and standard error mean of IPN distance and width of maxillary anterior in the Malaysian population. Statistics The average mean of the IPN distance in Indian population is 45.35, and in Malaysian population it is 47. Figure 1: Sample size calculation RESULTS To check the correlation between total mesiodistal width of six maxillary anterior teeth and interhamular notch distance, Karl Pearson correlation test was applied. The mean mesiodistal width of the six maxillary anterior teeth was mm, and the mean distance of the inter PMN was mm in Indian population. In the Malaysian population, the mean mesiodistal width of maxillary anterior teeth was mm, and the mean distance of the inter PMN was mm. There was a statistically significant positive correlation between the inter PMN distance and total mesiodistal width of the six maxillary anterior teeth. Table 1 shows the Pearson statistical correlation. Figure 2 shows the average mean of interpenetrating polymer network (IPN) distance in Indian and Malaysian population. In Figure 3, the average mean Figure 2: Average mean of IPN distance in Indian and Malaysian population Figure 3: Average mean of combined width of maxillary anterior in Indian and Malaysian population 527

4 Table 1: Pearson statistical correlation Population Statistical tool Inter PMN distance Total width of maxillary anterior teeth Indian Pearson correlation Significant (two-tailed) correlation is significant at the 0.01 level (2-tailed) Malaysian Pearson correlation Significant (two-tailed) Correlation is significant at the 0.05 level (2-tailed) Figure 4: Mean and standard deviation of IPN distance and width of maxillary anterior in Indian population Figure 5: Mean and standard deviation of IPN distance and width of maxillary anterior in Malaysian population The average mean of combined width of six maxillary anterior in dentate casts of Indian population is In Malaysian population, the average mean is In Indian population, the average mean of IPN distance is found to be 43.18, and the average mean of the total width of maxillary anterior was Standard deviation of IPN distance is 1.60 and that of the width of maxillary anterior is Standard error mean of IPN distance is and for the width of maxillary anterior it is In Malaysian population, the average mean of IPN distance is found to be 45.25, and the average mean of the total width of maxillary anterior was 47. Standard deviation of IPN distance is 1.90 and that of the width of maxillary anterior is Standard error mean of IPN distance is and for the width of maxillary anterior, it is DISCUSSION An important aspect in maxillary anterior teeth selection for complete dentures is the selection of the appropriate mesiodistal width of the six anterior teeth. However, a universally accepted method for accurate determination of the mesiodistal width of 528

5 anterior teeth has not yet been found. [9] Mesiodistal width of anterior teeth can be helpful as a guide for choosing the correct artificial teeth for partially edentulous patients. Artificial anterior teeth are highly important in the field of prosthodontics, attributing to its esthetic value and should be based on the shape and dimensions of teeth. [10] Esthetics is one of the essential factors considered in replacing maxillary anterior teeth. Successful rehabilitation takes into consideration the esthetic demands of today s patients, who are conscious of their appearance and will settle for nothing but the best from their dentist. [11] Tooth size must be considered to simulate lifelike appearance to the patient s prosthesis. Dentists are in search of an efficient method that can be used for determination of tooth size. Petricevic et al. stated that summation of width of six maxillary anterior teeth is equal to hamular notch distance. [12] Further studies on establishing relationship between maxillary anterior tooth size and inter PMN in other racial population groups are required to bring about a definite conclusion regarding this study. Johnson and Stratton17 stated that the width of the six anterior teeth equals the distance between the buccolingual centers of the PMNs plus 5 mm. [13] Literature has enunciated several different extraoral and intraoral techniques for prediction of dimensions of all the six maxillary anterior teeth, or individual tooth dimensions but the question still remains the same as which method can be generalized to all populations so that selection of teeth becomes easier for edentulous patients. [14] There are several anatomical parameters that would lead to the correct selection of maxillary anterior teeth. These anatomical parameters are: BW, interpupillary distance, inter-commissural distance, interalar distance, inner canthal distance, width of the upper lip philtrum, and nose length. [15] When width of maxillary anterior teeth are compared with external facial measurements (interpupillary, interalar, intercanthal, and intercommissural), only a weak positive correlation was found. [16] There was only limited research in the literature on BW as a guide for the selection of anterior teeth. [17] Up-to-date literature has shown so many different extraoral and intraoral techniques for prediction of either the dimensions of all maxillary anterior teeth or individual tooth dimensions, but the question still remains the same as which method can be generalized to all populations so that selection of teeth becomes easier for edentulous patients. [18] Anatomical landmarks which are reliable for selecting maxillary anterior teeth in edentulous individuals vary between different ethnic groups worldwide. Among certain population groups, namely Dakshina Kannada population, no correlation was found between the total mesiodistal width of maxillary six anterior teeth and inter-hamular notch distance, and hence, PMN cannot be considered as a reliable guide for selecting maxillary anterior teeth. This brings to a conclusion that newer studies for certain ethnic groups have to be implemented before considering any anatomical landmark is a reliable guide for selecting maxillary anterior teeth for that particular population. [19] Parameters like the proximal wearing of teeth with advancing age, gender variations in tooth size, ethnic variations, differences in size of dentition on the left and right sides and a specific sample size can limit the areas of this study. Although the application of anterior teeth measurements in forensic dentistry has been documented extensively, future efforts are needed to establish a common national or global database to assist in individual, gender, and ancestry identification. CONCLUSION There is a significant correlation between hamular notch distance and maxillary anterior width in this study, as justified from few other existing literature reports. PMN can used as a putative guide in the measurement of combined maxillary anterior width, irrespective of the different population groups. However, further research is recommended in this field, to establish a method that is universally accepted in maxillary anterior width measurement. Investigation of finding out the predictability of this approaches to estimate the maxillary anterior teeth width among different populations are required. Development of a more scientific, reliable and objective method for teeth selection would highly assist the dentists in delivering their services for patient care and satisfaction confidently and would also enable lab technicians to efficiently select the teeth even without seeing the patient on a dental chair. REFERENCES 1. Jain AR, Nallaswamy D, Ariga P, Ganapathy DM. Determination of correlation of width of maxillary anterior teeth using extraoral and intraoral factors in Indian population: A systematic review. World J Dent 2018;9: Pound E. Applying harmony in selecting and arranging teeth. Dent Clin North Am 1962;6: Frush JP, Fisher RD. How dentogenic restorations interpret the sex factor. J Prosthet Dent 1956;6: Engelmeier RL. Complete-denture esthetics. Dent Clin NorthAm 1996;40: Hasanreisoglu U, Berksun S, Aras K, Arslan I. An analysis of maxillary anterior teeth: Facial and dental proportions. J Prosthet Dent 2005;94: Ferrario VF, Sforza C, Dellavia C, Colombo A, Ferrari RP. 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6 measurements. Int J Prosthodont 2007;20: Sellen PN, Jagger DC, Harrison A. Methods used to select artificial anterior teeth for the edentulous patient: A historical overview. Int J Prosthodont. 1999;12: Johnson PF. Racial norms: Esthetic and prosthodontic implications. J Prosthet Dent 1992;67: Ranjan M, Raj R, Rohit, Chetan IK, Kumara R. Correlation between mesiodistal width of maxillary anterior teeth and interhamular notch distance amongst dakshin Kannada population. Int J Contemp Med Res 2017;4: Johnson DL, Stratton RJ. Fundamentals of Removable Prosthodontics. Chicago: Quintessence Publishing Co, Inc.; p Ayoub W, Rashid R. Evaluation of the current techniques and introduction of a novel approach for estimating maxillary anterior teeth dimensions in Kashmiri population. Int J Appl Dent Sci 2017;3: Strajni L, Vuleti I, Vuini P. The significance of biometric parameters in determining anteriorteeth width. Vojnosanit Pregl 2013;70: Ellakwa A, McNamara K, Sandhu J, James K, Arora A, Klineberg I, et al. Quantifying the selection of maxillary anterior teeth using intraoral and extraoral anatomical landmarks. J Contemp Dent Pract 2011;12: Rawat A, Godbole SR, Sathe S, Patidar N, Ramteke S. Evaluation of relation between bizygomatic width and mesiodistal dimension of maxillary central incisor in indian population: An in vivo study. Int J Sci Stud 2015;3: Sayed ME, Porwal A, Al-Faraj NA, Bajonaid AM, Sumayli HA. Evaluation of the current techniques and introduction of a novel approach for estimating maxillary anterior teeth dimensions. J Contemp Dent Pract 2017;18: Hoffman W Jr, Bomberg TJ, Hatch RA. Interalar width as a guide in denture tooth selection. J Prosthet Dent 1986;55: Source of support: Nil; Conflict of interest: None Declared 530

The correlation of bizygomatic width and ridge relationships in determination of width of maxillary anterior teeth

Research Article The correlation of bizygomatic width and ridge relationships in determination of width of maxillary anterior teeth Nor Masitah Mohamed Shukri 1, Ashish R. Jain * ABSTRACT Background: A