A histologic and histomorphometric evaluation of two types of retrieved human titanium implants

This study analyzed the interfacial human bone response to retrieved implants that had been functionally loaded in the human environment. A solid-screw titanium plasma-sprayed (TPS) implant was removed 5 years after implantation because of a fracture at the joint between the implant and the crown. A sand-blasted acid-etched titanium implant (SLA) was used as an anchorage for orthodontic treatment. At the end of the treatment, the SLA implant was removed. Both types were functionally loaded without any symptoms expressed by the patients. Histology showed bone contact between the TPS or the SLA implant and surrounding bone, but the SLA implant revealed much more interfacial bone contact. The contact microradiograms showed that the bone surrounding the TPS and SLA implants was highly calcified. The measured percentage of bone-implant contact around the SLA implant was significantly higher (P <.05) than that around the TPS implant.