REVIEW. Impacted Maxillary Canine - At a Glance ABSTRACT. Introduction. Prasad Konda, 1 Mohammad Urooj Ahmed, 2 Syed Mohammad Ali, 3 Amaranth Konda 4

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1 Impacted Maxillary Canine - At a Glance Prasad Konda, 1 Mohammad Urooj Ahmed, 2 Syed Mohammad Ali, 3 Amaranth Konda 4 Introduction Maxillary canine are important teeth in terms of esthetics, functional occlusion & arch development.the likelihood of their failing to erupt or becoming impacted may range between 1 & 3 %, 1 which shows its 2nd most commonly impacted tooth after the third molars. It is twice as common in females as it is in males. Incidence of canine impaction in maxilla is more than twice that of in mandible. Canine impaction is found palatally in 85% of cases and labially in 15%. ETIOLOGY ABSTRACT Maxillary canines are important teeth in terms of esthetic and function. Impaction of canines is a common occurrence and clinicians must have a sound knowledge to manage such cases. With early detection, timely interception and well managed surgical and orthodontic treatment; impacted canines can be erupted and guided to an appropriate location in the dental arch. This paper presents a literature review regarding etiology, clinical and radiographic diagnosis, as well as surgical and orthodontic management of impacted maxillary canine. KEYWORDS: Impacted canines, surgical techniques, orthodontic techniques. There is some incidence that patients with Angle s class II div 2 malocclusion and tooth aplasia may be at high risk to the development of ectopic canine. 2 LOCALIZED FACTORS 1) Tooth size arch length discrepancies. 2) Failure of the primary canine root to resorb. 3) Prolonged retention or early loss of the primary canine. 4) Ankylosis of the permanent canine. 5) Cyst or neoplasm. 6) Dilaceration of the root. 7) Absence of the maxillary lateral incisor. 8) Variation in root size of the lateral incisor. 9) Variation in timing of lateral incisor root formation. 10) Iatrogenic factors. 11) Idiopathic factors. SYSTEMIC FACTORS 1) Endocrine deficiencies. 2) Febrile diseases. 3) Irradiation. GENETIC FACTORS 1) Heredity. 2) Malposed tooth germ. 3) Presence of an alveolar cleft. 3 CLASSIFICATION : 4 Table 1 shows classification of impacted canine DIAGNOSIS OF IMPACTION: The diagnosis of canine impaction is based on both clinical and radiographic examinations. Clinical evaluation: It has been suggested that the following clinical signs might be indicative of canine impaction: (1) Delayed eruption of the permanent canine or prolonged retention of the deciduous canine beyond 14 to 15 years of age, (2) Absence of a normal labial canine bulge on palpation. (3) Presence of a palatal bulge, and (4) Delayed eruption, distal tipping, or migration (splaying) of the lateral incisor. According to Ericson and Kurol, 5 the absence of the "canine bulge" at earlier ages should not be considered as indicative of canine impaction. An accurate diagnosis of clinical examination should be supplemented with a radiographic evaluation. Radiographic evaluation: Several methods have been used to radiographically evaluate impacted maxillary canines. These methods include intraoral techniques (occlusal and periapical projections) and extraoral techniques (panoramic, posteroanterior or lateral cephalometric radiographs). 6 65

2 Occlusal radiographs: SEQUELE OF IMPACTIONS: The most practical method of obtaining an occlusal radiograph is by positioning the x-ray tube directly over the bridge of the nose, at a 60-degree angle to the occlusal plane. This method has been used to determine the bucco-palatal position of impacted teeth. Periapical radiographs: Traditional method of locating impacted teeth, specifically maxillary canines, has been the use of a twodimensional technique with periapical radiographs, known as the buccal object rule. This technique consists of taking two periapical radiographs at different mesiodistal angulations and using the same-lingualopposite buccal (SLOB) rule to determine the tooth s buccolingual position. The radiographic interpretation of the SLOB rule is if, when obtaining the second radiograph, the clinician moves the x-ray tube in a distal direction, and on the radiograph the tooth in question also moves distally, then the tooth is located on the lingual or palatal side. Accordingly, if the impacted canine is located buccally, the crown of the tooth moves mesially 3 Extra oral radiographs: (a) Frontal and lateral cephalograms can sometimes aid in the determination of the position of the impacted canine, particularly its relationship to other facial structures (e.g., the maxillary sinus and the floor of the nose). (b) Panoramic films are also used to localize impacted teeth in all three planes of space, much the same as with two periapical films in the tube-shift method, with the understanding that the source of radiation comes from behind the patient; thus the movements are reversed for position. 5 Cone-beam computed tomography (CBCT): Cone-beam computed tomography (CBCT) can identify and locate the position of impacted canines accurately. By using this imaging technique, dentists also can assess any damage to the roots of adjacent teeth and the amount of bone surrounding each tooth. In a study, Liu and colleagues 7 used CBCT to evaluate variations in location of impacted maxillary canines. They found that the position of impacted maxillary canines varies greatly. Reports of maxillary canine impactions vary considerably in orientation, and CBCT provides information to dentists so that they can properly manage impacted canines surgically and orthodontically. However, increased cost, time, radiation exposure and medicolegal issues associated with using CBCT, limit its routine use 8. Shafers et al suggested that the following sequel might be associated with canine impaction. -Labial or lingual mal-positioning of impacted tooth, -Migration of neighboring teeth and resultant loss of arch length, -internal resorption, -Dentigerous cyst formation, -External root resorption of the impacted as well as neighboring teeth, -Infections particularly associated with partial eruptions, -Referred pain, -Late resorption of the unerupted canine itself, -Loss of vitality of the incisors can occur, -Poor esthetics associated with primary canines. 5 DIFFERENT TREATMENT MODALITIES Each patient with an impacted canine must undergo a comprehensive evaluation of the malocclusion. The clinician should then consider the various treatment options available for the patient, including the following: (a) No treatment if the patient does not desire it. In such a case, the clinician should periodically evaluate the impacted tooth for any pathologic changes. It should be remembered that the long-term prognosis for retaining the deciduous canine is poor, regardless of its present root length and the esthetic acceptability of its crown. This is because, in most cases, the root will eventually resorb and the deciduous canine will have to be extracted. (b) Auto transplantation of the canine. (c) Extraction of the impacted canine and movement of a first premolar in its position. (d) Extraction of the canine and posterior segmental osteotomy to move the buccal segment mesially to close the residual space. (e) Prosthetic replacement of the canine. (f) Surgical exposure of the canine and orthodontic treatment to bring the tooth into the line of occlusion. This is obviously the most desirable approach. 5 MANAGEMENT OF IMPACTED MAXILLARY CANINES: The most desirable approach for managing the impacted maxillary canine is early diagnosis and interception of the potential impaction. In absence of prevention, orthodontic treatment and surgical exposure should be conducted. Kokich reported three methods for uncovering an impacted maxillary canine 66

3 Table 1: Classification Of Impacted Canine Group Proximity of line of arch Position in maxilla 1 Close Low 2 Close Forward low & mesial to lateral incisor root 3 Close High 4 Distinct High 5 Canine root apex is mesial to lateral incisor & distal to 1st premolar 6 Erupting in the line of arch in place of it, & resorption root of incisors. Impaction Table 2: Different Surgical Techniques For Labially And Palatally Impacted Canines Exposure Advantages Disadvantages technique Indications of surgical technique Labial Gingivectomy Canine cusp is coronal to the mucogingival junction adequate amount of keratinized gingival is present. Canine is not covered by bone Apically repositioned flap Closed eruption Canine crown is apical to MGJ, the amount of attached gingiva is minimized (used when less than 3 mm of attached gingival is present) Tooth is in the center of alveolus Crown is apical to MGJ Palatal Closed flap Canine is located near the lateral and central incisors, horizontally positioned and higher in roof of the mouth Open eruption Late mixed dentition Permanent dentition Indication of orthodontic treatment Orthodontic traction is not required as the tooth tends to erupt normally 2-3 week after surgery 1-2 weeks after surgery 1-2 weeks after surgery When eruption is at level of occlusal plane Easy to perform Less traumatic Commonly used: Conservation of keratinized gingival Greater esthetics Ease of tooth movement Immediate orthodontic traction can be applied Improved bone levels Little or no root resorption Fewer exposure, shorter over all treatment, less time, good oral hygiene during treatment Used only occasionally Loss of attached gingiva Possible damage to PDL Potential gingival overgrowth at surgical site. Increased risk of gingival recession, Height differences Relapse More traumatic Pt discomfort Possible mucogingival problems Bone recession, root resorption, longer operation time Repeat surgeries as a result of failure to erupt, Bond failure due to blood or saliva contamination Failure to erupt may extend total treatment time that is unable to influence the path of eruption 67

4 Open window eruption Tunnel traction Canine is located near the lateral and central incisor, horizontally positioned and higher in the roof of mouth Presence of primary canine in mouth 1-2 weeks after removal of pack The suture is removed 10 days after surgery & traction phase begin Visualisation of crown better control of direction of tooth movement avoidance of moving the impacted tooth in to the roots of adjacent teeth Reduced amount of bone around impacted tooth. The permanent canine is guided into permanent canine socket site Gingival overgrowth at incisor site Subjected to infection. Pt discomfort Requires the presence of primary canine Table 3 : Orthodontic Technique Used To Treat And Manage Impacted Maxillary Canines STUDY TECHNIQUE USED ADVANTAGES DISADVANTAGES Fischer and Colleagues 10 Cantilever system. Predictable tooth movement; low load or deflection; less frequent reactivations Potential side effects should be identified on the anchor tooth Park and Collegues 11 Temporary anchorage devices. (TADs) Could provide absolute anchorage for tooth movement; bonding of orthodontic brackets can be delayed until the canine is aligned Does not produce root movement; insertion and removal of TADs Kim and Colleagues 12 Schubert 13 Tausche and Harzer 14 Double-archwire Mechanics. Easy-Way-Coil (EWC) system. Auxiliary arm from transpalatal arch. Minimizes root resorption of the lateral incisors; allows horizontal tooth movement Constant application of force; a long activation distance; simple reactivation Simple design; simple Reactivation Requires laboratory procedure; patient discomfort Loosening of EWC attachment; infectious reactions in oral mucosa Requires laboratory procedure; tends to break easily Kornhauser and Colleagues 15 Auxiliary spring No laboratory pro -cedure; measured forces; complete eruption control; lack of damage to adjacent teeth Kalra 16 K-9 spring Simple design; Easy to fabricate and activate; continuous force Bishara 17 The ballista spring is a 0.014, 0.016, or inch round wire, which accumulates its energy by being twisted on its long axis. Control the direction of the eruption of the impacted tooth. Easily inserted and ligated. Provides a continuous force that is well controlled. Requires extra chair time to bend the spring Side effects on the posterior teeth Molars and premolars are affected 68

5 1. Gingivectomy 2. Apically repositioned flap 3. Closed eruption technique. 9 SURGICAL TECHNIQUES: 3 Table 2: Shows different surgical techniques for lingually and palatally impacted canines. ORTHODONTIC ATTACHMENT : To be in the position of being able to influence the future development of an impacted tooth, its necessary to place some form of attachment on the tooth. Different methods of attachment to the impacted tooth have been suggested, including crowns, wire ligatures, chain links, bands, and directly bonded brackets. It is strongly recommended that the surgical exposure of the impacted tooth be conservative to allow for the placement of a bonded bracket or button. ORTHODONTIC TECHNIQUES: Table 3: Shows orthodontic technique used to treat and manage impacted maxillary canines RETENTION CONSIDERATIONS: To minimize or prevent rotational relapse, a fiberotomy or a bonded fixed retainer may need to be considered by the clinician after completion of the desired movements and sometimes before the appliances are removed. Clark suggested that, after the alignment of palatally impacted canines, lingual drift can be prevented by removal of a "halfmoon-shaped wedge" of tissue from the lingual aspect of the canine. 5 Conclusion Management of the severely impacted canine is often a complex undertaking and requires the joint expertise of a number of clinicians. It is important that these clinicians communicate with each other to provide the patient with an optimal treatment plan based on scientific rational. When patients are evaluated and treated properly, clinicians can reduce the frequency of ectopic eruption and subsequent impaction of the maxillary canine. The simplest interceptive procedure that can be used to prevent impaction of permanent canines is the timely extraction of the primary canines. This procedure usually allows the permanent canines to become upright and erupt properly into the dental arch, provided sufficient space is available to accommodate them. Various surgical and orthodontic techniques may be used to recover impacted maxillary canines. Careful selection of surgical and orthodontic techniques is essential for the successful alignment of impacted maxillary canines. References 1. Eve T. and Winfried H. Treatment of a patient with Class II malocclusion, impacted maxillary canine with a dilacerated root, and peg-shaped lateral incisors. Am J Orthod Dentofacial Orthop 2008;133: Patrick F,Mcsherry. Ectopic maxillary canine :a review. BJO 1998; vol25;no3; Bedoya MM and Park JH. A review of the diagnosis and management of impacted maxillary canines. J Am Dent Assoc 2009;140; Becker A. The Orthodontic Treatment of Impacted Teeth. 2nd ed. Abingdon, Oxon, England: Informa Healthcare; 2007: Ericson S, Kurol J. Resorption of maxillary lateral incisors causedby ectopic eruption of the canines: a clinical and radiographic analysisof predisposing factors. Am J Orthod Dentofacial Orthop 1988;94(6): Bishara SE. Impacted maxillary canines: a review. Am J Orthod Dentofacial Orthop 1992;101: Liu DG, Zhang WL, Zhang ZY, Wu YT, Ma XC. Localization of impacted maxillary canines and observation of adjacent incisor resorption with conebeam computed tomography. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008;105(1): Elefteriadis JN, Athanasiou AE. Evaluation of impacted canines by means of computerized tomography. Int J Adult Orthodon Orthognath Surg 1996;11(3): Kokich VG Surgical and orthodontic management of impacted maxillary canines Am J Orthod Dentofacial Orthop 2004;126: Fischer TJ, Ziegler F, Lundberg C. Cantilever mechanics for treatment of impacted canines. J Clin Orthod 2000;34(11): Park HS, Kwon OW, Sung JH. Micro-implant anchorage for forced eruption of impacted canines. J Clin Orthod 2004;38(5): Kim SH, Choo H, Hwang YS, Chung KR. Doublearchwire mechanics using temporary anchorage devices to relocate ectopically impacted maxillary canines. World J Orthod 2008;9(3):

6 13. Schubert M. A new technique for forced eruption of impacted teeth. J Clin Orthod 2008;42(3): Tausche E, Harzer W. Treatment of a patient with Class II malocclusion, impacted maxillary canine with a dilacerated root, and peg-shaped lateral incisors. Am J Orthod Dentofacial Orthop2008;133(5): Kornhauser S, Abed Y, Harari D, Becker A. The resolution of palatally impacted canines using palatalocclusal force from a buccal auxiliary. Am J Orthod Dentofacial Orthop 1996;110(5): Kalra V. The K-9 spring for alignment of impacted canines. J Clin Orthod 2000;34(10): Jacoby H the ballista spring system for impacted teeth.am J Orthodofacial Orthop 1979;75(2): About the Authors 1. Dr. Prasad Konda Reader, Dept of Orthodontics and Dentofacial Orthopedics, Al Badar Dental College and Hospital, Gulbarga, Karnataka. 2 Dr. Mohammad Urooj Ahmed PG student, Dept of Orthodontics and Dentofacial Orthopedics, Al Badar Dental College and Hospital, Gulbarga, Karnataka. 3 Dr. Syed Mohammad Ali PG student, Dept of Orthodontics and Dentofacial Orthopedics, Al Badar Dental College and Hospital, Gulbarga, Karnataka. 4 Dr. Amaranth Konda MDS, Oral surgeon, Hyderabad. Address for Correspondence Dr. Prasad Konda Reader, Dept of Orthodontics and Dentofacial Orthopedics, Al Badar Dental College and Hospital, Gulbarga, Karnataka. docprasad18@yahoo.co.in ph: (+91)