The efficacy of bioresorbable fixation in the repair of mandibular fractures: An animal study

Abstract

Purpose: The efficacy of bioresorbable fixation has recently been described in the treatment of cranial vault deformities and in midfacial trauma. However, little to no data exist regarding its use in load-bearing areas. The purpose of this study is to analyze and compare the treatment of mandibular fractures by using a bioresorbable fixation system with a conventional titanium system in a canine model. Materials and Methods: Four adult beagles constituted the experimental group (A), and 2 beagles constituted the control group (B). Both groups underwent extraoral iatrogenic left mandibular angle osteotomies/fractures and open reduction and internal fixation by use of a bioresorbable fixation system (A) or a titanium fixation system (B). All operated animals were allowed to function immediately. Lateral skull radiographs were obtained preoperatively, immediately postoperatively after reduction, and at 3- and 6-month intervals. Preoperative and 6-month follow-up bite registrations were taken. At the 3-month interval, 1 animal from the experimental group was killed, and at 6 months the remaining animals were killed for morphologic, radiographic, and histologic analysis of the fractured interface and screw sites. Results: Morphologically, in the bioresorbable group, there was no clinical evidence of 1) intraoral/extraoral incisional dehiscence of wound infection; 2) deviation of the occlusion from maximum intercuspation; 3) intraoral/extraoral palpability of the device; 4) mobility of the fractured segments on manual manipulation; or 5) malunion as visualized at the time of sacrifice. All bioresorbable plates were clinically absent after 6 months and associated with adequate fixation and healing. Adequate restoration of function was achieved in both groups, with all of the animals showing weight gain. Radiographically, good alignment of the inferior border was seen, and histologically bony union was apparent in all specimens. Conclusions: This bioresorbable fixation system is effective in the treatment of mandibular angle fractures in a dog model, despite being placed in a load-bearing region. © 2000 American Association of Oral and Maxillofacial Surgeons