Corrosion of titanium dental implants has been associated with implant failure and is considered one of the triggering factors for peri-implantitis. This corrosion is concerning, because a large amount of metal ions and debris are generated in this process, the accumulation of which may lead to adverse tissue reactions in vivo. The goal of this study is to investigate the mechanisms for implant degradation by evaluating the surface of five titanium dental implants retrieved due to peri-implantitis. The results demonstrated that all the implants were subjected to very acidic environments, which, in combination with normal implant loading, led to cases of severe implant discoloration, pitting attack, cracking and fretting-crevice corrosion. The results suggest that acidic environments induced by bacterial biofilms and/or inflammatory processes may trigger oxidation of the surface of titanium dental implants. The corrosive process can lead to permanent breakdown of the oxide film, which, besides releasing metal ions and debris in vivo, may also hinder re-integration of the implant surface with surrounding bone.

At present, the exact mechanism for introduction of these materials and their role in peri-implantitis is unknown. Further research is warranted to determine their etiology and potential role in pathogenesis.

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The use of metal-on-metal (MoM) total hip implants has decreased recently due to reports of high failure rates and adverse local tissue reaction (ALTR). It has been hypothesized that wear metal debris released from CoCr bearing surfaces may provoke delayed hypersensitivity reactions. The goal of this study is to evaluate the microscopic bearing surface characteristics of implants revised due to evidence of ALTR. The bearing surface of each head and cup was analyzed using multiple microscopy techniques for characterization of the surface features. The presence of severe mechanical scratching was a common characteristic found in all of the implants evaluated. Mechanical factors seemed to be the prevalent failure mode related to the appearance of ALTR with this particular set of retrieved implants.

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Introduction: Total Hip Arthroplasty (THA) is considered one of the most successful orthopaedic interventions used for joint replacement. The purpose of this study was to characterize the particular surface features common to retrieved THA implants, in order to point out principal characteristics that lead to their failure. Methods: A set of fourteen retrieved implants was studied, their designs varying from metal‐on‐polyethylene (MoP), ceramic‐on‐polyethylene (CoP) and metal‐on‐metal (MoM). All specimens were analyzed using digital microscopy (Keyence VHX2000). Particularly corroded and scratched areas were further analyzed under Scanning Electron Microscopy (SEM, JEOL 5600), and Energy Dispersive X‐ray Spectrometer (EDS, JEOL 5600). Results: The surface analysis revealed certain patterns of features. The implants were divided in their components (cup, liner, head and stem), each of which was studied for common characteristics. Large amount of scratching was found throughout all of the heads and cups, followed by biological deposition on the surfaces, pitting and finally one single case of corrosion. Conclusion: The high level of scratching observed on the bearing surfaces of the implants leads to the belief that mechanical events induced failure of the implants. This study encourages surgeons to place higher importance of implant placement and material choice when applying THA. Grant Funding Source: Supported by the University of Texas at Dallas startup funds (Dr. Rodrigues)