New generation biodegradable plate for fracture fixation: comparison of bending strengths of mandibular osteotomies fixed with absorbable self-reinforced multi-layer poly-l-lactide plates and metallic plates--an experimental study in sheep.

Eighteen osteotomies of sheep's mandibular corpus were fixed: nine with self-reinforced multi-layer poly-l-lactide (SR-PLLA) plates and nine with metallic plates. Both plates were fixed with similar metallic screws. The right corpus of each sheep acted as a control. Radiographic analysis was carried out at 3 weeks and at sacrifice (6, 12 or 24 weeks) when the bending force needed to break the osteotomy site was measured. At 6 and 12 weeks of follow-up the osteotomy fixed with the PLA-plate seemed to tolerate the bending force better but no significant differences were detected at 3 or 24 weeks. The results have been satisfactory and have led the authors to continue with the development of a SR-PLLA plate-and-screw device for fracture fixation.