Incidence of unexpected condylar displacement following comprehensive orthodontic treatment in adults

Abstract

Objectives: To evaluate the incidence and pattern of unexpected/excessive condylar displacement after comprehensive orthodontic treatment in adults.

Materials and methods: Adult patients (age ≥18 years) who underwent comprehensive orthodontic treatment with pre-(T1) and post-treatment (T2) cone beam computed tomography scans were consecutively collected within an orthodontic cohort (N = 291). T1 and T2 CBCTs were superimposed three-dimensionally (3D) and condylar displacement was estimated by the 3D changes of condylar neck point (CdN) between T1 and T2 (ΔCdN). Participants with excessive condylar displacement (ΔCdN >1 mm) were classified as condylar displacement (+) and otherwise as displacement (-). The incidence and pattern of condylar displacement, association with factors such as sex, age, skeletal relationship, extraction pattern, treatment duration, history of temporomandibular joint disorder, and presence of condylar resorption with the final occlusal outcome were investigated.

Results: The incidence of unexpected condylar displacement >1 mm in the adult orthodontic cohort was 6.2%. Females (vs males; OR: 9.07; [95% CI: 1.19-69.23]) and Skeletal Class II (vs Classes I and III; OR: 4.57 [95% CI: 1.58-13.20]) demonstrated significantly higher odds of unexpected condylar displacement (P < .05). Condylar resorption was not evident in participants with condylar displacement and did not interfere with the final orthodontic outcome.

Conclusions: Unexpected 3D condylar displacement exceeding 1 mm was noted in approximately 7% of the adult orthodontic patient cohort. However, the condylar displacement per se was not associated with condylar resorption and did not cause clinical concerns.