Comparative Evaluation of Treatment Effectiveness in Skeletal Class III Malocclusion: Surgery-First Approach Using Clear Aligners Versus Fixed Appliances.

Objective: This study aimed to assess treatment outcomes, identify predictors of relapse in skeletal Class III patients treated with the surgery-first approach (SFA), comparing fixed appliances (FA) with invisalign clear aligners (CA).

Materials and methods: Forty adult patients treated with bimaxillary surgery and SFA were retrospectively enrolled: 20 with FA and 20 with CA. Serial cephalograms were obtained preoperatively (T0) and at 1 week (T1), 3, 6, and 12 months postoperatively (T2-T4). Intergroup differences were assessed using RM-ANOVA, independent-samples t-tests, and chi-squared tests. Predictors of relapse were identified using Pearson correlation and multiple linear regression analysis.

Results: Treatment duration and number of visits revealed no significant differences between the two groups. Most relapses occurred within the first 3 months postoperatively, followed by a gradual decline over the 12-month period. No significant differences in skeletal stability were observed between the FA and CA groups. However, the FA group exhibited significantly greater maxillary anteroposterior (AP) relapse (-0.98 mm) compared with the CA group (0.39 mm, p < 0.05). Multiple linear regression analysis revealed that FA treatment and greater maxillary advancement were positively associated with a greater magnitude of maxillary AP relapse. Additionally, mandibular AP relapse was associated with greater mandibular changes and less maxillary movement during surgery.

Conclusion: Treatment efficiency and skeletal stability were similar between FA and CA in SFA-treated Class III patients, though CA provided better maxillary stability. Close monitoring during the first 3 months post-surgery is recommended to prevent dental and skeletal side effects.

Trial registration: Registration number: ChiCTR2500104667.