Management of a partially ankylosed mandibular canine using controlled luxation, serial intraoral scan superimposition, and a customized lingual bracket: A case report

RATIONALE: Tooth ankylosis is difficult to diagnose and monitor because clinical signs are nonspecific, and radiographs provide only static information. PATIENT CONCERNS: An adult female was referred after prolonged orthodontic failure involving a nonresponsive mandibular left canine, severe anterior open bite, negative overjet, lower midline deviation, and repeated debonding of a stock lingual bracket. DIAGNOSES: The patient was diagnosed with partial ankylosis of the mandibular left canine, likely related to previous segmental osteotomy and fixation-screw proximity, together with a dental Class III relationship on a skeletal Class II base. INTERVENTIONS: Controlled luxation was performed, followed by stiff rectangular mechanics, miniscrew-anchored mandibular distalization, and serial intraoral scan superimposition. After repeated bracket failure, a scan-guided customized lingual bracket pad was fabricated and bonded. OUTCOMES: After just over 5 months, the canine was derotated, uprighted, and positioned within the arch. Bilateral Class I occlusion, normal overjet and overbite, midline correction, and lower occlusal plane leveling were achieved. The incisor mandibular plane angle decreased from 122.5° to 104.4°. Electric pulp testing remained positive, and no additional mandibular incisor root resorption was detected compared with the referral baseline. LESSONS: Serial intraoral scan superimposition may provide useful radiation-free evidence of post-luxation tooth movement, although registration error and crown-only assessment must be considered. A customized lingual bracket pad can improve bond reliability when heavy mechanics are required.