Facial Soft Tissue Changes in Class III Patients Treated With Bimaxillary, Maxillary Advancement or Mandibular Set Back Orthognathic Surgery

Objective: To determine the effect of orthognathic surgery on soft tissue in Class IIIpatients and to compare the results of different surgical techniques. Materials and Methods: Forty-eight Class III adult patients were included in the study to assessthe changes in the soft tissue after orthognathic surgery. Nine patients were treated with Maxillary Advancement (MA), seven patients were treated with Mandibular Set back (MS) and 32 patients were treated with Bimaxillary (BM) surgery. Cephalometric records were taken before treatment, after surgery and approximately 1 year after surgery (at the end of the treatment). Results: A significant change in mentolabial sulcus, St-Me, Sn-Me (p<0.01);Gl-Sn/Sn-Me, Pg^-HR (p<0.05) was observed in BM group. B^-VR and LLA-VR differed significantly in BM and MS groups after surgery (p<0.01). ULAVR and Sn-VR parameters differed significantly in MA and BM groups (p<0.01). Sn-HR, LLA-HR (p<0.05); ULA-HR, B^-HR, Sn-St (p<0.01) change differed significantly between MA-BM groups, whereas B-B^ (p<0.05), Sn-St (p<0.01) change differed significantly between MA-MS groups. In the BM surgery group; Pr, Sn and ULA-VR was affected or further with the underlying hard tissue movement in the comparison to the MA surgery. In the MS surgery LLA-VR and Pg^ was affected more from the mandibular posterior movement when compared to the BM group. Conclusion:The ratio of themean amount of soft tissue change and the skeletal change differ in three surgical groups, thus soft tissue prediction ratios should be done separately for three surgery groups.