Comparative analysis of root resorption and alveolar remodeling in maxillary incisors during orthodontic-orthognathic surgical treatment of skeletal Class III malocclusion.

INTRODUCTION

This retrospective clinical study investigated root length and periodontal changes around maxillary incisors in patients with Class III skeletal malocclusion treated with fixed appliances (FAs) and clear aligners (CAs) by cone-beam computed tomography.

METHODS

A total of 60 patients were equally divided into 2 groups based on the appliance type; cone-beam computed tomography scans were obtained before treatment, after presurgical orthodontic treatment, and after orthodontic-orthognathic treatment. The measurements of root length, vertical alveolar bone level, and horizontal alveolar bone thickness at 4 levels (3, 6, and 9 mm from the cementoenamel junction and root apex level) surrounding the maxillary incisors were compared. The tooth movement of maxillary incisors during the presurgical phase was evaluated.

RESULTS

The root length of maxillary incisors decreased in both groups, with the CA group experiencing a small reduction (1.09 ± 0.70 mm) compared with the FA group (1.29 ± 0.73 mm) after treatment. The FA group showed more pronounced reductions in palatal alveolar bone thickness and vertical alveolar bone level, along with greater root lingual movement during the presurgical orthodontic phase. Postsurgically, although both groups saw an increase in labial incisor inclination, the FA group primarily exhibited root lingual movement, as opposed to the labial tipping movement observed in the CA group.

CONCLUSIONS

The results indicated that FAs and CAs could trigger root resorption and marginal alveolar bone loss, with FA treatment associated with a more pronounced impact. Although CA may offer advantages in minimizing root resorption and conserving alveolar bone integrity, it provides inferior control over anterior torque compared with FA. Careful consideration is crucial to prevent iatrogenic degeneration during the whole phase of orthodontic-orthognathic surgical treatment.