[Soft and hard tissue changes after orthodontic and orthognathic treatment in patients with skeletal Class III...

To investigate soft- and hard-tissue changes and the association of these changes after orthodontic and orthognathic treatment in patients with skeletal Class III malocclusion.

The sample consisted of 20 patients with skeletal class III malocclusion treated with bilateral sagittal split ramus osteotomy (BSSRO). Lateral cephalograms taken before and after treatment were analyzed. All data were analyzed with SPSS13.0 software package for paired t test.

The distances of SNB, B and Pog to Y axis was smaller and ANB was larger after treatment. The labiomental angle, the distances of TLL,SB and TC to Y axis were smaller(P<0.01). The two pairs of SB-B and TC-Pog had linear correlation. The ratio was 1:1 and 0.84, respectively. The coefficient of determination R2 value of SB-B was 0.96 and the other was 0.97.

The patients with Class III malocclusion treated with orthodontic treatment and BSSRO can achieve satisfactory outcome. The single mandibular surgery did not affect the maxillary soft tissues. The changes of upper lip and lower lip length were not affected. The ratio of SB-B and TC-Pog corresponding soft- and hard-tissue ratio was 1:1 and 0.84, respectively. The coefficient of determination R2 values was all over 0.9.