Biological reactions to a poly(L-lactide)-hydroxyapatite composite: a study in canine mandible

In this study, bone response, possible use and ultimate fate of a chemically-synthesized poly(L-lactide)-hydroxyapatite (PLLA-HA) composite was experimented in canine mandible. Bilateral mandibular second premolars were extracted in four dogs. The PLLA-HA composite was placed into left surgical sites, and right extraction sites were used as controls. After three months of healing, bone specimens were harvested from each animal and processed for histological evaluation. Bone uptake of methylene diphosphonate (99mTc-MDP) was calculated as indicators of osteoblastic activity in the surgical sites. Histological evaluation and the amount of 99mTc-MDP uptake showed that all surgical sites had similar levels of cellular activity and the material was biocompatible. The experimental PLLA-HA composite studied is safe to be used as a small-defect filler in applications such as repair of alveolar defects, ridge augmentations, and sinus lift procedures.