Knowledge for Clinical Practice ETIOLOGY, DIAGNOSIS, & MANAGEMENT. By Christopher Canizares, DMD, and Laurance Jerrold, DDS, JD, ABO

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1 VOLUME 6 ISSUE 8 DENTAL LEARNING Knowledge for Clinical Practice A PEER-REVIEWED PUBLICATION ETIOLOGY, DIAGNOSIS, & MANAGEMENT By Christopher Canizares, DMD, and Laurance Jerrold, DDS, JD, ABO INSIDE Earn 2 CE Credits Written for dentists, hygienists, and assistants Integrated Media Solutions Inc./DentalLearning.net is an ADA CERP Recognized Provider. ADA CERP is a service of the American Dental Association to assist dental professionals in identifying quality providers of continuing dental education. ADA CERP does not approve or endorse individual courses or instructors, nor does it imply acceptance of credit hours by boards of dentistry. Concerns or complaints about a CE provider may be directed to the provider or to ADA CERP at Integrated Media Solutions Inc./Dental Learning.net designates this activity for 2 continuing education credits. Approved PACE Program Provider FAGD/MAGD Credit Approval does not imply acceptance by a state or provincial board of dentistry or AGD endorsement. 2/1/2016-1/31/2020 Provider ID: # AGD Subject Code: 370 Dental Learning, LLC is a Dental Board of California CE Provider. The California Provider # is RP5062. All of the information contained on this certifi cate is truthful and accurate. Completion of this course does not constitute authorization for the attendee to perform any services that he or she is not legally authorized to perform based on his or her license or permit type. This course meets the Dental Board of California s requirements for 2 units of continuing education. CA course code is

2 Impacted Canines: Etiology, Diagnosis, and Management ABSTRACT Impacted canines are frequently encountered in clinical practice and a common obstacle during routine orthodontic care. While canine impaction is multifactorial, the exact etiology is not always known. Impacted canines should be identified and diagnosed as early as possible to determine and permit the best path of treatment. In some cases, interceptive orthodontics at a young age can resolve canine impaction; for example, by extracting the primary canine and/or the primary first molar. Treatment options for impacted canines include extraction of primary canines and molars, rapid maxillary expansion, canine substitution, autotransplantation, surgical exposure, and orthodontic extrusion, and for those with a poor prognosis, extraction. EDUCATIONAL OBJECTIVES The overall goal of this article is to provide the reader with information on impacted canines. After completing this article, the reader will be able to: 1. Describe the radiographic investigations that may be required to assess impacted canines 2. List etiological factors for impacted canines 3. Review the rationale for interceptive orthodontics and methods used in intercepting impacted canines 4. List and describe treatment options and considerations involved in the treatment of impacted canines. ABOUT THE AUTHORS CHRISTOPHER CANIZARES DMD Christopher Canizares is currently a second year resident in Orthodontics and Dentofacial Orthopedics at New York University Langone Health s Advanced Education Program. He received his DMD from Boston University Henry M. Goldman School of Dental Medicine and completed a General Practice Residency at Montefiore Medical Center before practicing general dentistry for 5 years. Dr. Canizares can be reached at canizares.christopher@gmail.com. LAURANCE JERROLD DDS, JD, ABO Laurance Jerrold is a former Program Director for 4 ADA accredited orthodontic programs. His background includes 25 years of private practice in both orthodontics and law, and 20 years in full time academia. He received his DDS as well as his Orthodontic Specialty Certification from NYU College of Dentistry; his JD from Touro University; and a Certificate in Bioethics and the Humanities from Columbia University. Dr. Jerrold has presented or written well over 400 lectures, articles, textbook chapters, and presentations dealing with orthodontic practice, risk management, and clinical ethics. Dr. Jerrold is also the President of Orthodontic Consulting Group. Dr. Jerrold can be reached at drlarryjerrold@gmail.com. Introduction Impacted canines are an obstacle commonly encountered during routine orthodontic care. With the exception of third molars, maxillary permanent canines are the most commonly impacted tooth. Much of the literature focuses on maxillary canines, as the incidence of impacted mandibular canines is significantly less. The prevalence of maxillary canine impaction is estimated at 1-3%, with varying prevalence for different population groups. 1 In Bishara s research, an incidence of just 0.35% was reported for mandibular canine impaction. 2 Unilateral canine impaction is more often seen than bilateral impaction. Only 8% of patients with impacted canines have bilaterally impacted canines. 2 In addition, there appear to be gender differences in the prevalence of impacted maxillary canines. Some studies have found these to be 2.3 to 3 times more likely in females than males. 3 Impacted canines are also more likely SPONSOR/PROVIDER: This is a Dental Learning, LLC continuing education activity. STATEMENTS: Dental Learning, LLC is an ADA CERP recognized provider. ADA CERP is a service of the American Dental Association to assist dental professionals in identifying quality providers of continuing dental education. ADA CERP does not approve or endorse individual courses or instructors, nor does it imply acceptance of credit hours by boards of dentistry. Dental Learning, LLC designates this activity for 2 CE credits. Dental Learning, LLC is also designated as an Approved PACE Program Provider by the Academy of General Dentistry. The formal continuing education programs of this program provider are accepted by AGD for Fellowship, Mastership, and membership maintenance credit. Approval does not imply acceptance by a state or provincial board of dentistry or AGD endorsement. The current term of approval extends from 2/1/2016-1/31/2020. Provider ID: # EDUCATIONAL METHODS: This course is a self-instructional journal and web activity. Information shared in this course is based on current information and evidence. REGISTRATION: The cost of this CE course is $29.00 for 2 CE credits. 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3 Impacted Canines: Etiology, Diagnosis, and Management to be found palatally. Ericson and Kurol found that 85% of impacted canines were palatal and 15% buccal impactions. 4 Although erupting canines can be monitored in most children by clinical examination and digital palpation screening, radiographic investigation may be needed (Figures 1,2). One study found that radiographic investigation was needed in 8-10% of children. 5 The prevalence of maxillary canine impaction is estimated at 1-3%, with varying prevalence for different population groups. Figure 1. Panoramic radiograph of a 14-year-old male patient with a mesially impacted maxillary right permanent canine and over-retained maxillary right primary canine Figure 2. Panoramic radiograph of a 12-year-old male with an impacted mandibular right permanent canine and an over-retained mandibular right primary canine Resorption of the roots of adjacent permanent teeth is one of the most common and detrimental consequences of impacted canines, most often affecting the lateral and central incisors. Such resorption has been reported in approximately 12% of cases of ectopic maxillary canines in children 10 to 13 years of age. 4 In a systematic review of 18 studies investigating impacted canines and root resorption of adjacent teeth as evaluated using cone beam computed tomography (CBCT), Schroder et al reported that the prevalence of root resorption in lateral and central incisors ranged from 8.20% to 89.61%, and 1.19% to 35.06%, respectively. 1 While resorption in most cases was slight, in 30.9% of the cases severe resorption had occurred. 1 The presence of such resorption has serious implications for treatment planning. Another common sequela of impacted canines is migration of neighboring teeth, leading to a decrease in arch length. 6 Leaving unerupted teeth untreated can also result in ectopic eruption and in some cases cystic lesions of the follicle. 5 For these reasons, prudent monitoring and early diagnosis and treatment of ectopically erupting canines are paramount. Etiology The exact etiology of canine impaction is not known. However, it is believed that it is likely multifactorial. One of the primary etiological factors is believed to be tooth size arch length discrepancy. 6 In a review by Becker and Chaushu, four other factors in impaction are noted: local hard tissue obstruction (most commonly an over-retained predecessor, a supernumerary tooth, or an odontoma), local pathology (periapical granuloma caused by a nonvital primary tooth and trauma), deviation from normal development of the incisors (preventing normal eruption guidance of the canine), and genetic factors (abnormal location of a tooth germ sometimes leading to transposition with an adjacent permanent tooth, e.g., first premolars, aplastic lateral incisors). 3 In his observational study using radiographic assessment of impacted canines, Lappin found that primary canines were often present, frequently with unresorbed roots. 7 This led him to conclude that the principal factor resulting in impacted canines is delayed NOVEMBER

4 DENTAL LEARNING exfoliation of the deciduous canine. Some studies have found that extraction of primary canines, and even primary first molars, can redirect ectopically erupting canines into a more normal eruption path. These findings give further merit to the conclusions made by Lappin and will later be reviewed in detail. The roots of adjacent erupting teeth may also serve as an impediment to normal eruption of canines. Bishara also noted other causes of canine impaction, such as endocrine diseases, irradiation, and febrile diseases, as well as localized causes, including the presence of an alveolar cleft, ankylosis, or root dilaceration. 2 TABLE 1. Proposed etiological factors for canine impaction Discrepancy in tooth size arch length Supernumerary tooth Odontoma Roots of adjacent erupting teeth Delayed exfoliation of primary canine Ankylosis Root dilaceration Presence of an alveolar cleft Periapical granuloma Deviation from normal development of the incisors Abnormal location of a tooth germ Endocrine and febrile diseases Irradiation Diagnosis As noted previously, timely diagnosis of canine impactions is of utmost importance. The diagnosis of canine impaction is often based on both clinical inspection and radiographic evaluation. Bishara s research has suggested some clinical signs that may be indicative of impacted canines: a) prolonged retention of the primary canine beyond 14 to 15 years of age, or delayed eruption of the permanent canine; b) absence of normal labial canine bulge or an inability to localize canine position through intraoral palpation; c) presence of a palatal canine bulge; and, d) delayed eruption, distal tipping, or migration or splaying of the lateral incisor. 2 It should be noted, however, that Ericson and Kurol found that the absence of a canine bulge at an earlier age should not be considered indicative of canine impaction. In their study of 505 Swedish schoolchildren, 73% of 8-year-old children had maxillary canines whose position could not be determined by clinical evaluation, 29% had nonpalpable canines at age 10, and by 11 years of age this number had decreased to 5% 8 (Figure 3). These findings caution the practitioner to not blindly rely on the age of the child, as there is variation in eruption timing. Taking this into consideration, the decision to pursue radiographic evaluation relies on the practitioner s clinical judgment. The aforementioned clinical signs serve as a good basis for formulating this decision. Figure 3. Percentage of children with nonpalpable unerupted maxillary canines 8 April May April May April May 73% 29% 5% 8-year-olds 10-year-olds 11-year-olds 4 VOLUME 6 ISSUE 8

5 Impacted Canines: Etiology, Diagnosis, and Management Radiographic Analysis Radiographic inspection is crucial to treatment planning impacted canine cases. Research shows that, if indicated, the optimal age for radiographic inspection is 10 to 13 years. 5 Appropriate radiographic records can show the practitioner the location of the impacted tooth in all planes and provide insight on resorption of an adjacent tooth root. The orthodontist has various radiographic options (periapical, occlusal, panoramic, lateral cephalograms, CBCT at their disposal to assist in proper diagnosis of impacted canines. With all these options available, and the desire to limit unnecessary radiographic exposure ever-present, some recommendations are found in the literature as to what type of exposure is appropriate for particular cases. Periapical films provide the orthodontist with a 2-dimensional view of the dentition and can be used to evaluate the spatial relationship between teeth mesiodistally and superoinferiorly. To assess the position of the tooth buccolingually, a second periapical may be taken by employing the SLOB (same lingual opposite buccal) rule or buccal object rule. 6 Using the SLOB rule, two radiographs are taken of the same area with the horizontal angulation changed on the second exposure. If the object in question, in this case an impacted canine, moves in the same direction as the cone, the object is located palatally. If the object moves in the opposite direction of the cone, it is located buccally. When using the buccal object rule, vertical angulation of the cone is changed by approximately 20 degrees in two consecutive radiographs. Again, the buccal object will move in the opposite direction to the cone. Occlusal films can also be used to help determine the buccolingual orientation of an impacted canine. In one of their studies, Ericson and Kurol found that 2 to 3 conventional radiographs in different projections are often all that is needed in uncomplicated cases with aberrant eruption. 5 This study also found that the positions of the canines could be determined with accuracy in 92% of the cases studied with periapical films alone. 5 The need for additional radiographs is determined by problems caused by overlapping lamina dura and the risk of resorption. 5 Panoramic radiographs are a common diagnostic tool used in orthodontics to evaluate impacted canines. The benefit of these radiographs is that the entire dentition is visible to the practitioner at once, as well as other structures such as the temporomandibular joint and sinuses. However, the panoramic radiograph does come with certain limitations and has been found to be unreliable for determining the position of a misdirected canine in the dental arch and showing resorption of the adjacent tooth. 5 Based on their findings, Ericson and Kurol recommended reserving the use of panoramic radiographs for patients who are being considered for orthodontic treatment. 5 CBCT is another useful tool when dealing with canine impaction cases. First, CBCT can be used to accurately locate the position of an impacted canine in all three dimensions (Figures 4,5). Its greatest benefit, however, is that this image can provide the practitioner with valuable information concerning any root damage to adjacent teeth, as well as to surrounding bone. Some of the negative consequences attributed to routine CBCT use include increased cost, radiation exposure, and legal issues. 6 Therefore, judicious use of CBCT is recommended, and these images should be reserved Figure 4. CBCT of an 11-year-old female showing bilateral impacted canines transposed with their adjacent permanent lateral incisors. The upper left permanent canine is palatal to the root of the upper left central incisor. NOVEMBER

6 DENTAL LEARNING Interceptive Treatment When diagnosed early, impacted canines can be addressed by interceptive methods in an effort to correct their eruption path. One method of addressing errant canines is by selective extraction of the deciduous canines. In a seminal study evaluating the eruption of palatally erupting canines, Ericson and Kurol found that the extraction of maxillary primary canines had a favorable effect on palatally erupting maxillary permanent canines. 4 In this study, 46 ectopic palatally placed maxillary canines in boys and girls ranging in age from 10 to 13 years of age were evaluated. The investigators used panoramic, periapical, and lateral cephalograms to evaluate these canines in various planes (frontal, transverse, and sagittal). For 36 of 46 canines, the eruption path normalized after extraction of the primary canines, and the permanent canines obtained a correct position. The likelihood of normalization was found to diminish as the crown of the impacted canine moved more mesially. For instance, 91% of impacted canines whose crowns overlapped less than half of the lateral incisor's root normalized. 4 This number dropped to 64% for cases in which the canine overlapped the adjacent incisor by more than half of the lateral root 4 (Figure 6). Despite this, the study clearly illustrates the effect that extraction of primary canines can have on palatally erupting permanent canines. There is some literature advocating taking this extraction protocol a step further and extracting the first primary molar Figure 5A. CBCT of the previously shown 12-year-old male (Figure 2) with a mesially impacted lower right canine. Figure 5B. Sagittal slice of the CBCT, showing the impacted canine is located buccal to the roots of the mandibular incisors. Figure 6. Percentage of canine impactions and root normalization, based on the degree to which the canine crown overlapped the root of the adjacent lateral incisor for patients in whom the state of the lateral incisors cannot be determined in other ways and the risk of injury is great. 5 CBCTs can be used to accurately locate the position of an impacted canine in all three dimensions and provide valuable information concerning any root damage to adjacent teeth. 91% Overlap <50% of the lateral incisor root 64% Overlap >50% of the lateral incisor root 6 VOLUME 6 ISSUE 8

7 Impacted Canines: Etiology, Diagnosis, and Management in addition to the primary canine. By extracting the primary first molar, the permanent first premolar is encouraged to erupt and create more room to allow the impacted canine to erupt into the proper position. Bonetti et al conducted a study in Italy comparing the dentition of nonorthodontic patients between the ages of 8 and 13 years. 9 In this study, 71 subjects were separated into 3 groups depending on perceived risk of canine impaction. Those subjects with increased risk for canine impaction were then separated into two treatment groups: primary canine extraction only or primary canine/ primary first molar extraction. Extraction of the primary canine/molar resulted in a clinically significant difference, with more favorable changes in intrabony position of the maxillary canine and an increased rate of normal eruption of the canine when compared to the primary canine extraction only group. 8 Figures 7 and 8 are panoramic radiographs of a female patient, taken 6 months apart. In this case, the upper primary canines, along with the upper right primary second molar were extracted. This resulted in spontaneous correction of the upper left permanent canine eruption path and in improvement of the upper right permanent canine. In addition to primary tooth extraction, orthodontic procedures to gain space and increase arch length have been recommended as an interceptive measure for impacted canines. A study by Sigler et al found that use of a rapid maxillary expander (RME) followed by use of a transpalatal arch (TPA), in combination with extraction of primary canines in the late mixed dentition, significantly increased the rate of eruption in 80% of palatally displaced canines when compared to an untreated control group. 10 This study advocated the use of this protocol in conjunction with primary canine extraction for patients ages 9 years 5 months to 13 years. 10 The use of cervical pull head gear is another method employed to maintain and even increase arch length in an effort to provide impacted canines with a more favorable eruption environment. Armi et al conducted a study comparing no treatment with the use of cervical headgear alone or cervical headgear in combination with RME as an interceptive measure. 11 Successful canine eruption was reported for 82.3% and 85.7%, respectively, for the headgear-only group and the RME followed by headgear group, both with a statistically significant difference compared to the no-treatment (control) group. 11 In another study with 46 subjects, Leonardi et al found Figure 7. Panoramic radiograph showing the maxillary and mandibular arches of a female patient at age 10 years and 9 months Figure 8. Panoramic radiograph showing spontaneous correction of the upper left permanent canine eruption path, and improvement of the upper right permanent canine, 6 months following extractions NOVEMBER

8 DENTAL LEARNING TABLE 2. Interceptive methods for canine impaction 8-11 Selective extraction of the deciduous canine Selective extraction of the deciduous canine + first primary molar RME and later TPA + extraction of the deciduous canine Use of cervical headgear ± RME Extraction of primary canine + RME that extraction of primary canines alone did not increase the rate of normal eruption for malerupting canines, but that their extractions in conjunction with cervical pull head gear was effective. 12 This prospective study randomly allocated the subjects into three groups: primary canine extraction only group, primary canine and cervical pull headgear group, and a control group. A statistically significant difference was found between the primary canine/headgear group and the primary canine extraction and no-treatment (control) groups. However, contrary to the findings of Ericson and Kurol, no statistically significant differences in outcomes were found between the primary canine extraction only group and the no-treatment (control) group. 4 Successful eruption was observed in 80% of cases treated using the cervical pull head gear and primary canine extraction protocol. 4 These studies, along with others, support the notion that maintaining or increasing arch length can promote favorable eruption of impacted canines. Treatment Various treatment options are available for patients with impacted canines if interceptive treatment is not employed, is unsuccessful, or if the impacted canine presents a surgical risk or has a poor prognosis for eruption due to horizontal angulation. Depending on the severity of impaction and probability of orthodontic success, the impacted tooth can be considered for extraction. Manne et al cite several clinical situations in which impacted canine extraction could be indicated. These situations include ankylosed canines, internal or external root resorption, severely dilacerated roots, impactions that may result in root resorption of adjacent teeth during orthodontic treatment, and those with cystic formation or infection. 6 Retaining the primary canine in its place is an option, although the practitioner must always consider the questionable long-term prognosis of doing so. If the prognosis of the primary canine is poor, it too should be extracted. At this point, either a restorative replacement (implant/crown, bridge, removable denture, retainer with pontic) can be considered, or orthodontic movement of the first premolar into the canine position with subsequent protraction of the posterior teeth in that quadrant. Another treatment option, known as canine substitution, involves extracting the lateral incisor to allow the canine to erupt in its position. Esthetic concerns such as inherent differences in shape, size, and shade between canines and lateral incisors should be taken into consideration when selecting this treatment. Zachrisson et al listed the following as advantages of canine substitution: a) children will receive their final result at a younger age, as there is no need to wait for the patient to mature for implant placement; b) overall treatment can be completed after orthodontics; and, c) adaptation of the teeth and supporting structures will appear natural in the long term with this option. 13 Indications for extraction of impacted canines include ankylosis, internal or external root resorption, severely dilacerated roots, cystic formation, infection, and impactions with a risk of root resorption of adjacent teeth during orthodontic treatment. 6 Due to its esthetic characteristics, role in lip support, and importance in masticatory function (for example, canine guidance), when possible, the movement of the impacted canine into its proper position in the arch is preferred. Surgical options can accomplish this. 8 VOLUME 6 ISSUE 8

9 Impacted Canines: Etiology, Diagnosis, and Management Autotransplantation Autotransplantation involves atraumatic surgical removal of the impacted tooth, creation of a socket at the donor site, and then re-implantation of the previously impacted tooth into the newly created site in proper position. 14 Autotransplantation is very technique sensitive and its success is dependent on a number of factors. Patel states that the presence of a viable periodontal ligament is critical for long-term success, but notes that patient age, developmental stage of the transplanted tooth, and the length of the extra-alveolar time before transplantation are factors in success rates. 14 Teeth with incomplete root formation have been shown to have higher transplantation success rates. This treatment option is viable for patients unwilling to undergo orthodontic treatment and who present with an associated deciduous canine with a poor long-term prognosis. In their retrospective study investigating the long-term success of autotransplanted maxillary canines with closed root apices, Patel et al found an 83% survival rate for 63 transplanted teeth in 49 patients, with an average duration of 14.5 years in situ. This study did, however, find greater periodontal problems associated with the transplanted canines. Of the parameters investigated, they found statistically significant differences in probing pocket depth and bleeding on probing. The increased probing pocket depths of the transplanted canines still fell within the range of normalcy. The authors cautioned that low long-term success is expected and that individual success is often hard to predict. 14 Success factors for autotransplantation include the presence of a viable periodontal ligament, younger patient, minimal length of time the tooth is extra-alveolar, and immature root development. Exposure and Orthodontic Extrusion A more commonly employed surgical option involves exposure of the impacted canine, often followed by orthodontic extrusion to achieve a proper position for the canine. Two surgical techniques are available for exposure, the closed and the open techniques. The closed technique involves surgical exposure of the impacted tooth via a mucoperiosteal flap and placement of an attachment for orthodontic traction followed by repositioning of the flap over the tooth. In the open technique, the canine is exposed by a gingival flap or complete removal of bone and tissue over the tooth (at which point a surgical dressing can be placed and later removed after several days). The exposed tooth is then left to erupt on its own, or an attachment placed for orthodontic movement (button or bracket depending on how much tooth surface is exposed and how far the tooth is from the dental arch). For spontaneous eruption to occur, Kokich proposed removal of bone around the impacted canine crown to the level just short of the cemento-enamel junction after its uncovering, and then allowing the tooth to erupt prior to orthodontic treatment to move it towards the alveolar ridge. 15 Results of research comparing the two techniques are equivocal. In one review, Parkin et al found some evidence suggesting that there are no differences in outcomes between the two techniques when exposing a palatally displaced maxillary canine. 16 In a systematic review conducted by Cassina et al, however, results favoring the open exposure technique were found. 17 Eight randomized and prospective nonrandomized clinical trials were included in the review, resulting in a total of 453 identified impacted canines in 433 patients. For 220 canines (48.6%), an open exposure surgical technique was performed, and the remaining 233 (51.4%) canine exposures were achieved using the closed technique. 17 The open surgical technique was found to be associated with a statistically significant reduction of 2.14 months in treatment duration for initial canine alignment to the dental arch compared to treatment using the closed technique. 17 The authors posited that this result may have been due to the repositioned flap serving as an impediment to canine eruption. This review found only one statistically significant difference among the secondary outcomes studied that the open surgical technique was associated with a statistically significantly decreased risk of ankylosis. The exact cause of an increased risk of ankylosis with the closed surgical NOVEMBER

10 DENTAL LEARNING technique is uncertain, and the authors attributed trauma to the PDL by the low-speed bur and inappropriate orthodontic forces as possible factors. 17 In both reviews, it was noted that there are limited trials investigating this topic, and it was suggested that more research is needed. Conclusions Canine impaction is a commonly encountered clinical phenomenon. It presents the practitioner with three challenges: proper diagnosis, treatment planning, and execution of treatment. Early diagnosis and interceptive treatment, if possible, is preferable as the literature shows that certain measures (selective extraction of primary teeth, arch length expansion, or preservation via RME or headgear) can be initiated to assist the impacted canine correct its eruption path. If the impacted canine is not diagnosed early and interceptive measures are not taken (or fail), several options are still available to treat the condition. At this point, several factors must be considered when deciding among treatment options, such as the probability of success and weighed against potential risks such as damage to adjacent teeth. Whether extraction, autotransplantation, or surgical exposure is chosen, correspondence with the oral surgeon or periodontist performing the procedure is of paramount importance. When properly diagnosed and with surgical/orthodontic treatment properly administered, impacted canines can effectively be brought into the arch in their proper position, ending in an esthetic and stable result. References 1. Schroder A, Guariza-Filho O, Miranda de Araujo C, Ruellas A, Tanaka O, Pororatti A. To what extent are impacted canines associated with root resorption of the adjacent teeth? A systematic review with meta-analysis. J Am Dent Assoc. 2018;149(9): e8. 2. Bishara S. Impacted maxillary canines: a review. Am J Orthod Dentofac Orthop. 1992;101(2): Becker A, Chaushu S. Etiology of maxillary canine impaction: a review. Am J Orthod Dentofac Orthop. 2015;148(4): Ericson S, Kurol J. Early treatment of palatally erupting maxillary canines by extraction of the primary canines. Eur J Orthod. 1988;10: Ericson S, Kurol J. Radiographic examination of ectopically erupting maxillary canines. Am J Orthod Dentofac Orthop. 1987;91(6): Manne R, Gandikota C, Juuvadi S, Rama H, Anche S. Impacted canines: Etiology, diagnosis, and orthodontic management. J Pharm Bioallied Sci. 2012;4(Suppl 2): S Lappin MM. Practical management of the impacted maxillary canine. Am J Orthod 1951;37: Ericson S, Kurol J. Longitudinal study and analysis of clinical supervision of maxillary canine eruption. Community Dent Oral Epidemiol. 1986;14: Bonetti G, Zanarini M, Parenti S, Marini I, Gatto M. Preventive treatment of ectopically erupting maxillary permanent canines by extraction of deciduous canines and first molars: a randomized clinical trial. Am J Orthod Dentofac Orthop. 2011;139(3): Sigler L, Baccetti T, McNamara J. Effect of rapid maxillary expansion and transpalatal arch treatment associated with deciduous canine extraction on the eruption of palatally displaced canines: A 2-center prospective study. Am J Orthod Dentofac Orthop. 2011;139(3): e Armi P, Cozza P, Baccetti T. Effect of RME and headgear treatment on the eruption of palatally displaced canines: a randomized clinical study. Angle Orthod. 2011;81(3): Leonardi M, Armi P, Franchi L, Bacetti T. Two interceptive approaches to palatally displaced canines: a prospective longitudinal study. Angle Orthod. 2004;74(5): Zachrisson B, Rosa M, Toreskog S. Congenitally missing maxillary lateral incisors: canine substitution. Am J Orthod Dentofac Orthop. 2001;139(4): 434, 436, 438 passim. 14. Patel S, Fanshawe T, Bister D, Cobourne M. Survival and success of maxillary canine autotransplantation: a retrospective investigation. Eur J Orthod. 2011;33: Kokich V. Preorthodontic uncovering and autonomous eruption of palatally impacted maxillary canines. Seminars in Orthodontics. 2010;16(3): Parkin N, Benson PE, Thind B, Shah A, Khalil I, Ghafoor S. Open versus closed surgical exposure of canine teeth that are displaced in the roof of the mouth (review). Cochrane Database Syst Rev. 2017;8:CD Cassina C, Papageorgiou S, Elidares T. Open versus closed surgical exposure for permanent impacted canines: a systematic review and meta-analyses. Eur J Orthod. 2018;40(1): VOLUME 6 ISSUE 8

11 Impacted Canines: Etiology, Diagnosis, and Management CEQuiz To complete this quiz online and immediately download your CE verification document, visit www. dentallearning.net/ic-ce, then log in to your account (or register to create an account). Upon completion and passing of the exam, you can immediately download your CE verification document. We accept Visa, MasterCard, Discover, and American Express. 1. The prevalence of maxillary canine impaction is estimated at, and an incidence of has been reported for mandibular canine impaction. a. 0.5 and 1%; 0.15%. b. 1 and 1.5%; 0.3% c. 1 and 2%; 0.35% d. 1 and 3%; 0.35% 2. Ericson and Kurol found that of impacted canines were palatal impactions. a. 75% b. 80% c. 85% d. 90% 3. Resorption of is one of the most common and detrimental consequences of impacted canines. a. opposing permanent teeth roots b. adjacent permanent teeth roots c. adjacent bone d. the impacted canine s root 4. Leaving unerupted teeth untreated can result in. a. supereruption b. ectopic eruption c. tooth germ abnormalities d. malignancies 5. One of the primary etiological factors in canine impaction is believed to be. a. tooth size arch length discrepancy b. Class II crowding c. a crossbite d. tooth size arch width discrepancy 6. is a factor in canine impaction. a. Local hard tissue obstruction b. Local pathology c. Deviation from normal development of the incisors d. All of the above 7. Based on radiographic assessment of impacted canines, Lappin believed that the principal factor resulting in impacted canines is. a. delayed eruption of the permanent dentition. b. lack of space and an anterior crossbite c. delayed exfoliation of the deciduous canine d. accelerated eruption of the first premolar 8. Some studies have found that extraction of primary canines, and even primary first molars, can redirect ectopically erupting canines into a more normal eruption path. a. True b. False 9. Which of the following is not associated with canine impaction? a. ankylosis b. eiichymoto syndrome c. root dilaceration d. alveolar cleft 10. is a clinical sign that may be indicative of impacted canines. a. Retention of the primary canine beyond 14 to 15 years of age b. Distal tipping of the lateral incisor c. An inability to localize canine position through intraoral palpation d. All of the above 11. The presence of a palatal canine bulge is a sign of. a. an impacted canine b. physical abuse c. dens invaginatus d. None of the above 12. The absence of a canine bulge at an early age is indicative of canine impaction. a. True b. False 13. In a study with more than 500 Swedish schoolchildren, of 8-year-old children had maxillary canines whose position could not be determined by clinical evaluation. a. 53% b. 63% c. 73% d. 83% 14. With respect to canine impaction, research shows that the optimal age for radiographic inspection is years. a. 8 to 11 b. 9 to 12 c. 10 to 13 d. 11 to Periapical films can be used to evaluate the spatial relationship between teeth. a. buccally and palatally b. mesiodistally and palatobuccally c. palatobuccally and distolingually d. mesiodistally and superoinferiorly 16. The acronym SLOB in SLOB rule stands for. a. simple lingual opposing buccal b. same lingual opposite buccal c. same lateral opposing buccal d. simple lateral outer buccal NOVEMBER

12 DENTAL LEARNING CE QUIZ 17. When two consecutive radiographs are taken, and the vertical angulation of the cone is changed by approximately 20 degrees for the second one, this is known as the. a. angulation rule b. 20-degree rule c. buccal rule d. vertical angulation rule 18. The greatest benefit of cone beam computed tomography (CBCT) when evaluating canine impactions is. a. locating the position of the impacted canine in three dimensions b. understanding the occlusion factors involved c. obtaining information on any root damage to the adjacent teeth and to surrounding bone d. none of the above 19. Negative consequences attributed to routine CBCT use include increased cost, radiation exposure, and legal issues. a. True b. False 20. When diagnosed early, one interceptive method of addressing impacted canines is by. a. selectively extracting deciduous canines b. extracting the first primary molar in addition to the primary canine c. orthodontic treatment to increase arch length and space d. All of the above 21. In one study, a greater percentage of impacted canines achieved a correct position after extraction of the primary canine when the impacted canine. a. moved more mesially b. overlapped the adjacent lateral incisor by less than half c. moved more buccally d. moved more mesially and buccally 22. Use of a rapid maxillary expander followed by a transpalatal arch (TPA), in combination with extraction of primary canines in the late mixed dentition, significantly increased the rate of eruption in of palatally displaced canines in one study. a. 60% b. 70% c. 80% d. 90% 23. An impacted canine presenting with severe horizontal angulation has a better prognosis than would otherwise be the case. a. True b. False 24. Extraction of an impacted canine may be considered in a number of situations, one of which is if it. a. is ankylosed b. is undergoing internal/external root resorption c. has severely dilacerated roots d. All of the above 25. When a lateral incisor is extracted to allow the canine to erupt in its position, this is referred to as. a. canine lateralization b. canine substitution c. incisal substitution d. canine-incisal transfer 26. is one of the reasons movement of an impacted canine into its proper position is preferred over extraction. a. Its role in lip support b. The age of the patient c. The gradual manner in which treatment is performed d. All of the above 27. The long-term success of autotransplantation has been found to depend on several factors, including the. a. patient s gender b. presence of a viable periodontal ligament c. presence of an opposing tooth d. patient s use of antimicrobial rinses 28. Teeth with incomplete root formation have been shown to than fully developed teeth. a. be at greater risk of ankylosis b. have higher transplantation success rates c. integrate more slowly d. have lower transplantation success rates 29. Surgical exposure of an impacted canine is often followed by. a. minimally invasive exfoliation of the tooth b. orthodontic extrusion to achieve a proper position for the canine c. rapid self-directed eruption of the canine into position d. the need for root canal therapy within 6 months 30. When properly diagnosed and with surgical/orthodontic treatment properly administered, impacted canines can effectively be brought into the arch in their proper position, ending in an esthetic and stable result. a. True b. False 12 VOLUME 6 ISSUE 8

13 CE ANSWER FORM ( address required for processing) Impacted Canines: Etiology, Diagnosis, and Management Name: Title: Specialty: Address: NPI No.: City: State: Zip: AGD Identification No.: Telephone: License Renewal Date: EDUCATIONAL OBJECTIVES Describe the radiographic investigations that may be required to assess impacted canines List etiological factors for impacted canines Review the rationale for interceptive orthodontics and methods used in intercepting impacted canines List and describe treatment options and considerations involved in the treatment of impacted canines. AGD Codes: 370 QUIZ ANSWERS Fill in the circle of the appropriate answer that corresponds to the question on previous pages. 1. A B C D 16. A B C D COURSE EVALUATION Please evaluate this course using a scale of 3 to 1, where 3 is excellent and 1 is poor. 1. Clarity of objectives Usefulness of content Benefit to your clinical practice Usefulness of the references Quality of written presentation Quality of illustrations Clarity of quiz questions Relevance of quiz questions Rate your overall satisfaction with this course Did this lesson achieve its educational objectives? Yes No 11. Are there any other topics you would like to see presented in the future? PLEASE PHOTOCOPY ANSWER SHEET FOR ADDITIONAL PARTICIPANTS. Please direct all questions pertaining to Dental Learning, LLC or the administration of this course to jriley@dentallearning.net. COURSE EVALUATION and PARTICIPANT FEEDBACK: We encourage participant feedback pertaining to all courses. Please be sure to complete the evaluation included with the course. INSTRUCTIONS: All questions have only one answer. Participants will receive confirmation of passing by receipt of a verification certificate. 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A B C D 5. A B C D 6. A B C D 7. A B C D 8. A B C D 9. A B C D 10. A B C D 11. A B C D 12. A B C D 13. A B C D 14. A B C D 15. A B C D 17. A B C D 18. A B C D 19. A B C D 20. A B C D 21. A B C D 22. A B C D 23. A B C D 24. A B C D 25. A B C D 26. A B C D 27. A B C D 28. A B C D 29. A B C D 30. A B C D Price: $29 CE Credits: 2 Save time and the environment by taking this course online. If you have any questions, please Dental Learning at questions@dentallearning.net or call VOLUME 6 ISSUE 8