Management of Impacted Mandibular Canine

Mandibular canines are much less frequently impacted than the maxillary canines. Most mandibular canines are found in a labial position. But sometimes they can be in the mental protuberance area or lying transversely at the lower border of mandible. They can migrate to the opposite side of the mandible, i.e. transposition of canine (Figs 23.1A and B, 23.2A and B).

  Such teeth maintain their original innervation and this fact has to be considered when removing them under local anesthesia. Patients with impacted mandibular canine also presents with symptoms comparable to that of impacted maxillary canine like retained deciduous teeth, proclination/displacement of adjacent incisors (Figs 23.3A and B) or clinical features associated with cyst formation (Figs 23.4A and B). Impacted canines may remain symptom free and are then discovered accidentally in a routine radiograph or while investigating for other diseases (Figs 23.5). It may sometimes lead to recurrent pain and infection (Figs 23.6A and B).

Treatment
The following treatment options should be considered in the management of impacted mandibular canine:
1. Observation: In many cases this modality is acceptable if indications for removal do not exist like impingement on adjacent tooth, development of follicular cyst or as a part of the planned orthodontictreatment. The retained primary may be permitted to continue for an extended period. However, the impacted tooth should be periodically reviewed to assess the development of pathologic changes.

2. Exposure and orthodontic repositioning: This can be considered if there is adequate space for the accommodation of the tooth in the arch and if the angulation of the tooth is favorable, i.e. deviation of the long axis of the tooth is not excessive. The treatment is carried out in the same manner as for the maxillary canine.

3. Surgical repositioning: This may be considered as an alternative treatment option if exposure and orthodontic repositioning is not possible. The optimal time for surgical repositioning appears to be before the root formation is complete, i.e. when the apical foramen is still wide open. In such cases pulpal revascularization and periodontal healing are very predictable. With further root development, the tooth may require endodontic treatment.

4. Surgical removal of the tooth: The following are the indications for the removal of impacted mandibular canine:
a. Evidence of pathology around the tooth, e.g. follicular cyst, tumor.
b. Close proximity of the follicle to the marginal periodontium of the adjacent tooth.
c. Orthodontic need to move adjacent tooth into the area.

Surgical Anatomy (Fig. 23.7)
Compared to maxillary canine the bone encasing the mandibular canine is thick. The lingual cortical bone in the mandibular canine region is very thick, whereas the buccal bone is rather thin. The impacted mandibular canines are often located mesial or distal to the canine region. Surgical access to the tooth is obtained by raising a buccal flap. A lingual flap is seldom raised due to insufficient access and marked postoperative morbidity associated with it. While raising the buccal flap, the insertion of mentalis and incisive muscle is severed. The incisive muscle is inserted at the height of the canine alveolus while the mentalis arises from the mental fossa.


Removal of Mandibular Canine (Figs 23.8 A to H)
A standard trapezoidal (3 sided) flap or a horizontal incision below the attached gingiva can be used to expose the tooth. A tooth close to the lower border of mandible may require an extraoral incision and dissection for proper exposure. Bone removal is done with burs and chisel and the tooth can be removed by simple elevation or after sectioning.


Case report A 16-year-old girl was advised surgical removal of impacted 33 before starting orthodontic treatment. The following is the surgical steps (Figs 23.9 A to L):

Complications of Surgical Removal

The following complications may occur during the procedure:
1. Accidental injury to adjacent tooth—During bone removal to expose the impacted canine damage to the supporting bone of the lateral incisor may occur leading to loosening of the tooth. If this happens, the involved tooth should be splinted to the adjacent tooth.

2. Mental nerve injury—This can happen if the distal vertical incision is carried too far backwards and inferiorly.

Removal of Impacted Mandibular Canine in an Edentulous Patient
The technique of removal is essentially the same with some modifications and additional precautions. The incision is often given on the crest of the alveolar ridge if the tooth is closer to the ridge. If it is closer to the inferior border, an incision in the sulcus should be considered. As in the case of impacted mandibular third molar due to the extreme resorption of the alveolar ridge and sclerosis of bone in the old age, use of excessive force should be avoided to prevent fracture of mandible. Moreover, there may be pathology associated with the impacted canine which also has to be looked into which further weakens the mandible. Any associated systemic disease contraindicating the surgery has to be considered during the planning stage.
   The following is the case report of surgical removal of impacted left mandibular canine transposed to midline in a 56-year-old man (Figs 23.10A to K). The patient reported with recurrent swelling of the sub mental region of two years duration associated with occasional intraoral pus discharge. He was wearing complete denture for the last seven years. He gave a history of treatment for hypertension for the last three years and the disease was well controlled with medication.