Bio-absorbable plates and screws for internal fixation of mandibular fractures. A study in six dogs.

Bio-absorbable plates and screws were used for internal fixation of artificially created mandibular fractures in 6 dogs. The plates and screws were fabricated from a block of poly(L-lactide) (PLLA), with a high molecular weight. The material is microporous and has excellent mechanical properties. Plates and screws were inserted in accordance with Champy's principles on internal fixation. Clinical and radiographical follow-up and examination of the fracture site under general anesthesia showed that all fractures healed without callus and without complications. The plates or screws did not fail, despite the tensile strength of the PLLA used is less than stainless steel or any other metal. An explanation for their successful application may be the high impact resilience of this material. The proprioceptive mechanisms, however, that keep the dogs from maximal loading of their broken mandibles, may also play a role. Plates and screws of this bio-absorbable PLLA appear to be an attractive alternative for internal fixation of mandibular fractures and certainly for less loaded fractures of the human skeleton. The necessity to remove metallic osteosynthesis can be avoided.