Retrieval analyses of a blade implant after 231 months of clinical function.

A blade implant that was retrieved in 1990 after 231 months of clinical function (since 1971) was analyzed with respect to clinical, histological, and biomechanical characteristics. The implant clinical records demonstrated no abnormalities or pathological lesions over the tenure of treatment. The bone to implant interface showed a mixture of interfacial tissue components and conditions with adequate direct bone contact (46.4 to 82.3 percent) for classification as osseointegrated. The abutment fracture leading to removal was characterized as a cyclic fatigue mechanism and the distribution of tissue components along the interface could not be correlated with specific biomechanical loading directions. This report considers the clinical and biomechanical records as they relate to the detailed histological investigation.