Self-Reinforced Biodegradable Screw Fixation Compared With Titanium Screw Fixation in Mandibular Advancement

This report compares the skeletal stability and treatment outcomes of 2 similar cohorts undergoing bilateral sagittal osteotomies of the mandible for advancement. The study groups included patients stabilized with 2-mm self-reinforced polylactate (PLLDL 70/30), biodegradable screws (group B), and 2-mm titanium screws placed in a positional fashion (group T). Sixty-nine patients underwent bilateral sagittal osteotomies of the mandibular ramus for advancement utilizing an identical technique. There were 34 patients in group B and 35 patients in group T. Each patient had preoperative, immediate postoperative, splint out, and 1-year postoperative cephalometric radiographs available for analysis. The method of analysis and treatment outcomes parameters are identical to those previously used. Repeated measures analysis of variance was performed with means of fixation as the between-subject factor and time as the within subject factor. The level of significance was set at .01. There were no clinical failures in group T and a single failure in group B. The average difference in stability between the groups is small and subtly different at the mandibular angle. The data documented similarity of the postsurgical changes in the 2 groups with the only statistically significant difference being the vertical position of the gonion ( P < .001) and the mandibular plane angle ( P < .01) with greater upward remodeling at gonion in group T. Two-mm self-reinforced PLLDL (70/30) screws can be used as effectively as 2-mm titanium screws to stabilize the mandible after bilateral sagittal osteotomies for mandibular advancement. The difference in 1-year stability and outcome is minimal.