Two Human Hydroxyapatite-Coated Dental Implants Retrieved After a 14-Year Loading Period: A Histologic and Histomorphometric Case Report

• Autores: Giovanna Lezzi, Antonio Scarano, Giovanna Petrone, Adriano Piattelli
• Localización: Journal of periodontology, ISSN 0022-3492, Vol. 78, Nº. 5, 2007, págs. 940-947
• Idioma: inglés
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• Resumen

  • Background: Controversy over the long-term clinical effectiveness of hydroxyapatite (HA)-coated dental implants still persists, despite numerous clinical studies documenting high survival rates. Concerns about the degradation of the coating over the years have been raised; it has been speculated that resorption of the HA could produce a space between the implant and the bone with a resultant mechanical instability.

    Methods: Two HA-coated implants were retrieved due to a fracture of the abutment screws after a loading period of 14 years and were treated to obtain thin ground sections for histologic evaluation.

    Results: At low-power magnification, it was possible to observe that the HA coating was in contact with mature bone. No gaps or connective fibrous tissue was found at the implant–bone interface. No epithelial downgrowth was present. No acute or chronic inflammatory cell infiltrate was present at the implant–bone interface. No foreign body reaction was present in the peri-implant tissues. Some osteocytes were in direct contact with the coating. For implant 1, the percentage of bone–titanium contact was 25% ± 2.1%, and the percentage of bone–HA contact was 35% ± 1.4%. The total bone–implant contact was ∼60%. The HA coating appeared to be resorbed in 46% ± 3.2% of the implant perimeter, especially in the coronal portions of the implant. For implant 2, the mean percentage of bone–HA contact was 13% ± 1.8%, and the mean percentage of bone–titanium contact was 15% ± 2.3%. The total bone–implant contact was ∼28%. The HA coating appeared to be resorbed for a mean of 68% ± 4.1% of the implant perimeter, especially in the coronal portion of the implant.

    Conclusions: No acute or chronic inflammatory cell infiltrate was present in the peri-implant tissues. No signs of coating infection, fatigue, or failure were observed in two specimens. The HA coating may not be susceptible to degradation or dissolution under long-term function.