Phu Hnin Thet. A retrospective study in comparison of skeletal stability and pharyngeal airway changes in mandibular prognathism after correction with mandibular setback surgery using two different types of osteofixation materials. Master's Degree(Oral and Maxillofacial Surgery). Chulalongkorn University. Office of Academic Resources. : Chulalongkorn University, 2021.
A retrospective study in comparison of skeletal stability and pharyngeal airway changes in mandibular prognathism after correction with mandibular setback surgery using two different types of osteofixation materials
Abstract:
Objectives: This study compared the skeletal stability and pharyngeal airway changes after mandibular setback procedure using the titanium and resorbable plate and screws fixation. Materials and Methods: 28 patients with mandibular prognathism being treated with bilateral sagittal split ramus osteotomy (BSSRO) were randomly selected from titanium and resorbable fixations. Analyses of lateral cephalometric x-rays were performed according to preoperative (T0), 1st week post-surgery (T1), 3-6 months post-surgery (T2) and 1-year post-surgery (T3). The horizontal measurement (BX), vertical measurement (BY), and angle measurement (SNB and Mandibular Plane Angle; MPA) were studied for skeletal stability. The pharyngeal airway changes were observed by nasopharynx (NOP), uvula (UOP), tongue (TOP) and epiglottis (EOP). Results: There were no significant difference of mandibular setback in titanium (6.61±3.97 mm.) and resorbable groups (5.08±3.21 mm.). Significant MPA changes were found in both titanium and resorbable groups in 3-6 months post-surgery, but MPA still expressed significant changes in the resorbable group in 1-year post-surgery (2.29±0.59; p-value=0.006). The resorbable group was found significant EOP changes (-1.21±0.3 mm; p-value=0.02) in 3-6 months post-surgery, then gradually returned to no significant changes in 1-year post-surgery. Conclusion: This study could be demonstrated that osteofixation with resorbable plates and screws was comparable to titanium in long-term pharyngeal airway dimension, but a tendency to relapse, particularly mandibular plane angle.