The orthodontic management of ectopic canine.

The canines being the cornerstone of the arch and smile is one of the teeth, which has the longest eruption passage that gets influenced by local and general etiological factors easily. The initial calcification of the crowns starts at 4-5 months of age and proceeds toward eruption about 11-13 years of age with mesiobuccal crown angulation that gets corrected toward occlusion. It gets displaced buccally or palatally or may sometimes get impacted. Early intervention is the best suited to manage canine eruption patterns. Once erupted ectopically, they possess a great challenge in repositioning them back into their correct position. This case report discusses an orthodontic treatment planning and execution to correct a buccally placed canine with an anterior crossbite in an adult.

The permanent canines are a key tooth in the maxillary arch that defines the smiles arc. It gets displaced ectopically either palatally or buccally with buccal displacement being twice less common than palatal displacement. The etiology of ectopic canine is multifactorial with the local factors and heredity being more related to the buccal displacement of the canines. Chaushu et al.,[1] showed that buccally displaced canines were accompanied with a larger maxillary anteriors. Lateral Incisors are often peg shaped or undersized adjacent to impacted maxillary canines.[2] A study by Basdra et al.,[3] shows that there is very little relationship between displaced/impacted canine and horizontal skeletal characteristics. Tooth size and arch length discrepancy play a very important role in displacement of the canines.[4]

Case Report

SG 20-year-old female complained of irregularly placed upper front tooth and feels uncomfortable to smile. History elicited, revealed no history of orthodontic treatment done before, and she does not remember any extractions done during mixed dentition period, her past medical history was not significant. On extraoral examination [Figure 1a–c], she had apparently symmetrical face, with a straight profile, competent lips, increased exposure of teeth during smile and an average growth pattern. Intraoral finding [Figure 2a–e] revealed the presence of the full complement of permanent teeth except third molars, no carious teeth were present, and she had a good oral hygiene. Examination of the arches revealed a V-shaped upper arch and U-shaped lower arch, both asymmetrical; molars were in class I relation, and class I canine on the left side, with blocked upper right lateral incisor, upper right canine was placed ectopically on the buccal side close to the upper right central incisor, almost in a transposed position. Anterior crossbite was present on the right side of the arch, and a midline shift of both the upper lower arches toward the right side by 4 mm. The overjet and overbite of 2 mm. Model analysis revealed a space discrepancy of 4 mm in the upper and 3 mm in the lower. She was diagnosed as Angles class I malocclusion with ectopic canine, anterior cross bite, upper and lower anterior crowding and an average growth pattern.

Figure 1

(a-c) Pre treatment extra oral

Figure 2

(a-e) Pre treatment intra oral

Problem list

Bucally placed canine

Anterior crossbite

Blocked lateral incisor

Crowded upper and lower anteriors

Midline shift in upper and lower arches.

Treatment plan

Nonextraction treatment was planned with a 022 MBT bracket system. Mild arch expansion and mild proclination of the upper and lower anteriors were intended to gain space. Bite blocks were used initially for few months to correct the anterior crossbite. Transpalatal arch was included for reinforcing anchorage. Fixed retention was planned for upper and lower arches.

Treatment progress

At first, the upper arch was strapped up [Figure 3a–c], aligning was achieved with 014 NiTi and followed by 016 NiTi. We corrected the anterior crossbite in the upper right centrals first, then opened the space for right upper laterals using NiTi open coil spring. The upper right lateral was bonded with an inverted lateral incisor bracket to reverse the torque. After bringing the laterals into the arch 16 × 22 NiTi was used to start leveling the arch, it was followed by 17 × 25 NiTi, then to 17 × 25 SS, then into 19 × 25 NiTi. Once leveling was achieved, finishing was done using 19 × 25 SS wire to gain torque.

Figure 3

(a-c) Mid treatment Intra oral

Fixed retention in both upper/lower arches from canine to canine was given.

Treatment results

The posttreatment results showed that pleasing smile was achieved [Figure 4a–c] and a good alignment of the canines was achieved in class I relation on both the sides. The anterior crossbite was corrected. The lower anterior crowding was corrected by mild proclination. The midline was maintained. The molar was maintained class I. Overjet and overbite of 2 mm was achieved. The upper midline was shifted to the left side by 2 mm, lower midline stayed the same [Figure 5a–e].

Figure 4

(a-c) Post treatment extra oral

Figure 5

(a-e) Post treatment intra oral

Discussion

Facial displacement of the maxillary canines is mainly attributed to the inadequate space in the arch. Patients with palatally displaced canines usually have more arch length available than patients with buccally displaced canines.[5] Prediction of the canine is an important factor for successful treatment. Moss[6] insist on careful examination of (1) space analysis, (2) the morphology of the adjacent teeth, (3) contours of the bone, (4) mobility of the teeth, (5) radiographic examination. The buccally displaced canines were also associated with the hyperdivergent growth pattern, and constricted maxillary arch, and crowded upper anteriors.[7] It is very essential to identify the root resorption of the neighboring tooth before treatment. Studies by Rimes et al.,[8] have shown that resorption of the roots of the laterals is very common in buccally displaced canines. The present diagnostic advancement of cone beam computerized tomography with its three dimensional view enables us to assess the presence of resorption. Early assessment helps to plan the direction of movement to be intended first.

Conclusion

An early examination and good clinical evaluation with necessary investigations help us predict the correct position of the canines. Success toward the management of the ectopic canines lies in a thorough planning. The case report elicits a simple easy approach to manage buccally displaced ectopic canines.