Calcium phosphate coatings elaborated by the soaking process on titanium dental implants: Surface preparation, processing and physical-chemical characterization.

OBJECTIVE: Dental implant manufacturers are looking for new surfaces to improve osseointegration. It is accepted that calcium phosphate coatings favor bone healing. Among all the techniques, the soaking process seems attractive because of its ability in producing a bioactive coating at low temperature. The objective of this study is to improve the titanium implant surface roughness and chemistry by optimizing the surface preparation and the soaking process parameters to produce a bioactive and adherent calcium phosphate coating. METHODS: Titanium samples were sandblasted and acid etched. Coatings were realized by an alternate soaking process including a centrifugation step to create a phosphate solution thin film on the implant that reacts with the calcium of the second bath. We performed a characterization of the sample surface with complementary physical and physico-chemical techniques to assess the effect of surface preparation and coating process operating parameters on coating formation and characteristics. RESULTS: Surface preparation led to a roughness around 1.6mum, micro-porosities, high surface wettability and removed the embedded sandblasting particles. We showed that the centrifugation step is critical and determines the coating formation, coverage and thickness. A thin coating ( approximately 2mum) composed of apatite analogous to bone mineral was deposited. The coating adhesion was demonstrated by screwing/unscrewing test in an artificial jawbone. SIGNIFICANCE: The titanium dental implant pre-treatment and coating developed in this study is expected to favor early implant osseointegration through coating dissolution in vivo and could be associated with biological active agents to confer additional functionality to the coating.