RESUMO
The stability and degradability of hydroxyapatite coatings on dental implants depends on the dissolution of the individual chemical phases. Hydroxyapatite-coated dental implants exhibit a range of amorphous-phase content. Two tests were conducted to observe the course of coating degradation. The first test showed degradation of both crystalline and amorphous coatings by cracking and dissolution after immersion in Ringer's solution. Concomitant saturation of the implants in the solution modified the coated surface with precipitated crystalline apatite. A second test, intended to replicate the conditions of infection by decreasing pH, illustrated preferred dissolution of the amorphous phase, liberating crystalline segments. It is expected that morphologic changes could influence the rate of bone bonding and therefore could alter or control implant-tissue interactions.
Assuntos
Materiais Biocompatíveis/química , Implantes Dentários , Durapatita/química , Apatitas/química , Infecções Bacterianas/metabolismo , Materiais Biocompatíveis/análise , Fosfatos de Cálcio/análise , Fosfatos de Cálcio/química , Fenômenos Químicos , Precipitação Química , Físico-Química , Ácido Cítrico/química , Cristalização , Durapatita/análise , Humanos , Concentração de Íons de Hidrogênio , Imersão , Soluções Isotônicas/química , Teste de Materiais , Osseointegração , Porosidade , Solução de Ringer , Solubilidade , Propriedades de Superfície , Difração de Raios XRESUMO
This case demonstrates the successful use of a hydroxylapatite block for maintenance of ridge contour. The procedure offers an alternative to guided tissue regeneration for treating osseous defects of the buccal cortical plate, which may occur following tooth extraction.
