Human cadaveric histomorphological and metallurgical analysis of dental implants following 12.5 years of service

Abstract

OBJECTIVES: To provide a metallurgical and histomorphological analysis of hybrid bridgework and associated dental implants which have been in a clinical load bearing situation for a period of 12.5 years. MATERIAL AND METHODS: The physical integrity of the hybrid framework was examined with stereoimaging microscopy and scanning electron microscopy for signs of wear, fatigue cracks, corrosion. Elemental spectra and maps of the surface were analysed with an EDAX Detecting Unit (AMETEK, Inc, Mahwah, NJ, USA). Similarly, the supporting titanium abutments screwed into the implants were examined for fatigue and corrosion. Bone density scans and bone trabecular patterns were obtained from radiographs. Microcomputer tomography was used to assess the bone-implant interface and bone architecture around the implants. Histological sections were stained with 1% basic fuchsin to assess osseous microdamage. RESULTS: The study demonstrated that the gold alloy framework to be in satisfactory condition with little indication of corrosion or cracking. The interface between the gold alloy and the titanium abutments likewise demonstrated no obvious corrosion cells. No radiographic evidence of any adverse loss of bone around the implants was noted. Bone mineral density was related to implant position, being higher between the implants. Scanning electron micrograph images confirmed the good bone integration with the implant threads with a high level of organisation, maturation and adaptation for the entire length of the implant. There was no evidence of any microdamage. CONCLUSIONS: The implants, abutments and hybrid framework were in remarkably good condition considering their length of service.