GBR with an e-PTFE membrane associated with DFDBA: histologic and histochemical analysis in a human implant retrieved after 4 years of loading.

As a result of a fracture to the cemented post and core, a pure titanium implant was extracted from a 54-year-old patient after 4 years of clinical loading. At implantation, the implant was positioned into an extraction socket and the defect was treated with an e-PTFE membrane associated with a DFDBA graft. At retrieval the implant underwent histologic and histochemical examination to assess the characteristics of the regenerated bone after 4 years of prosthetic loading. The implant showed an angular bony defect at the smooth collar, but the bone-implant direct contact rate seemed to be elevated in the remaining implant surface. Normal transmitted and polarized light examinations demonstrated that most of the DFDBA particles were resorbed and substituted by vital newly formed bone. The regenerated bone appeared compact with secondary osteons and large haversian canals; however, some partially mineralized remnants residuated in the spaces, between the osteons. Within the limits of this study, the authors concluded that DFDBA can be substituted by the host bone, but the rate of substitution is very slow and not complete after 4 years. From a clinical point of view, however, the load-bearing capacity of the bone regenerated with the membrane technique associated with DFDBA appeared to be similar to that of normal bone.