Comparative Study of Facial Soft Tissue Profile Changes following Bilateral Sagittal Split and Subcondylar Osteotomies in Patients with Mandibular Prognathism

بررسي مقايسه‌اي تغييرات پروفايل بافت نرم صورت متعاقب جراحي استيوتومي دو طرفه ساجيتال و ساب كنديلار در بيماران مبتلا به پروگناتيسم منديبل

Objective: Programming for a successful operation and accurate prediction of the outcome of orthognathic surgery result in correction of occlusal and skeletal relations and improve the facial esthetics and function of patients. This retrospective study sought to assess the soft tissue changes following subcondylar and bilateral sagittal split osteotomy (BSSO) to retrude mandible in patients with mandibular prognathism. Methods: This retrospective experimental study evaluated 35 patients with mandibular prognathism and a mean age of 25.5 years (range 18.8 to 30.9 yrs). Cephalometric variables were measured on lateral cephalograms of patients before and after surgery and recorded. A total of 12 patients had undergone BSSO while 23 subjects had received subcondylar surgery. Cephalometric variables were analyzed using paired t- and independent t-tests. Results: The study results demonstrated that the mean changes in cephalometric soft tissue variables of Ls-Pr (P < 0.05), Li-Id (P < 0.01) and G-Sn/Sn-Me (P < 0.05) after BSSO were significantly higher that the rates in Subcondylar surgery group. However, the mean changes in soft tissue variables of SLs-A (P < 0.05), a2 facial angle (P < 0.05) and LFH (P < 0.001) in subcondylar surgery group were significantly higher than the rates in BSSO group. In patients that had undergone subcondylar surgery, the lower facial height and the mentocervical angle had increased which is indicative of a shift towards a straight facial profile after this type of surgery. Conclusion: This study showed that a greater improvement in profile is achieved after BSSO compared to subcondylar surgery according to the current esthetic parameters.