Histologic and histometric evaluation of rat alveolar wound healing around polyurethane resin implants

The biocompatibility of polyurethane resin implants derived from castor bean (Ricinus communis) was analyzed in the rat dental alveolus. Histometric evaluation of trial areas adjacent to the implants showed, by week 1, the polymer granules encircled by a conspicuous capsule and surrounded by immature connective tissue. By weeks 2 and 3, the implants were surrounded by less prominent fibrous capsules, and most of the tested area was occupied by mature trabecular bone. By week 6, the fibrous capsule was thinner, and the tested area was almost totally covered with bone, which in several places was in close contact with the implants. The results suggest that the material is compatible, as it was progressively integrated into alveolar bone in the wound-healing process.