Changes of the soft tissue profile in skeletal class III patients treated with orthodontic-surgical treatment

Objective To explore the changes of the soft tissue profile in skeletal class Ⅲ patients treated with orthodontic-surgical treatment. Methods The samples consisted of 35 skeletal class Ⅲ patients treated with orthodontic-surgical treatment. Standardized lateral cephalograms at the following stages were taken for each patient : T0(pretreatment), T1(preoperative), T2( postoperative), T3(posttreatment). Fifteen soft tissue parameters, and eleven bone and dental parameters were measured at different stages. Repeated measurement variance analysis was used for comparison of each parameter between 4 stages, and Least-Significant Difference (LSD)test was used for comparison between any 2 stages. Results (1)Between stage T0 and T3: soft tissue convexity increased. Soft tissue facial angle decreased. Nasolabial angle increased. The protrusion of the upper lip increased, and that of the lower lip decreased (P 0.05). Conclusions Through orthodontic-surgical treatment, facial profile has been improved greatly in skeletal class Ⅲ patients. Through preoperative orthodontic decompensation treatment, the soft tissue profile has further deteriorated. Between stages of postsurgery and posttreatment, soft and hard tissues were relatively stable. It is necessary to pay attention to the downward movement of the UL and LL points along with the surgery. Key words: Skeletal class Ⅲ malocclusion; Orthodontic-surgical treatment; Soft tissue profile