Ultrastructural and Immunocytochemical Characterization of the Bone-Single Crystal Sapphire Implant Interface in the Rat Maxilla

To evaluate the suitability of a new implant animal model, we examined the host response to single crystal sapphire implant into the rat maxilla socket and characterized the regenerating tissue-implant interface using a combination of morphological and immunocytochemical approaches. At 2, 4, and 8 weeks after implantation, animals were sacrificed and tissues processed for morphological or immunocytochemical studies. Results demonstrated that nonmineralized connective tissue was present between bone and the implant surface. However, in some situations at 8 weeks, direct bone contact was observed. Electron microscopy revealed that the interface between the implant and the regenerating tissues was characterized by the presence of either cells or an intervening extracellular matrix layer that had a variable appearance and thickness.The bone-implant interface was immunoreactive for osteopontin. The rat maxilla socket implant model, due to its ease of management and its similarities to other previous experimental animal models, seems to be useful for some specific implant experimental studies.