The correlation between mandibular repositioning and relapse of incisor inclination after Class II surgical-orthodontic treatment

Abstract

The objective of this study was to find the correlation between mandibular repositioning (mandibular counterclockwise rotation and mandibular advancement) and incisor inclination relapse observed after Class II surgical-orthodontic treatment during their six to twelve month follow-up. In addition, post-surgical skeletal relapse of the mandible was evaluated for its correlation with the following incisor inclination relapse after deband.

Twelve patients who underwent surgical-orthodontic treatment and bimaxillary orthognathic surgery, with either B-SSRO or B-VNSO, after being diagnosed as Class II malocclusion with mandibular retrognathism were evaluated. Lateral cephalograms were measured at five time points; initial (T0), pre-surgery (T1), post-surgery (T2), deband (T3), and six to twelve month follow-up (T4).

Significant changes between each time points were evaluated using paired t-test. From this evaluation, it was noticeable that the skeletal and dental changes occurred mainly between time points T2 and T3, the post-surgical orthodontic treatment stage.

The correlation evaluation between the skeletal changes made during surgery and dental relapse showed no correlation. However, post-surgical skeletal relapse of mandibular advancement and dental relapse displayed significant correlation with each other. Based on such result, careful observation of the skeletal relapse of mandibular advancement during the post-surgical orthodontic treatment stage could provide some guideline on how much incisor inclination relapse to expect after deband.