Chronology of alveolar healing following immediate implantation of Ricinus communis polyurethane resin: histometric analysis in rats.

The purpose of the present study was to determine whether granules of Ricinus communis polyurethane resin implanted immediately after tooth extraction interfere with the time course of alveolar wound healing in rats. Progressive bone neoformation in parallel to a decrease in the volume fraction of connective tissue was quantified by a histometric method 1, 2, 3, and 6 weeks after tooth extraction. In spite of the biocompatible nature, the presence of polyurethane resin granules in the cervical third led to a small (9-22%) but significant delay in bone formation in the middle and apical alveolar thirds from the second week on, as compared to controls.