Antibacterial Electrodeposited Copper-Doped Calcium Phosphate Coatings for Dental Implants.

Dental implants provide a good solution for the replacement of tooth roots. However, the full restoration of tooth functions relies on the bone-healing period before positioning the abutment and the crown on the implant, with the associated risk of post-operative infection. This study aimed at developing a homogeneous and adherent thin calcium phosphate antibacterial coating on titanium dental implants by electrodeposition to favor both implant osseointegration and to limit peri-implantitis. By combining global (XRD, FTIR-ATR, elemental titration) and local (SEM, Raman spectroscopy on the coating surface and thickness) characterization techniques, we determined the effect of electrodeposition time on the characteristics and phases content of the coating and the associated mechanism of its formation. The 1-min-electrodeposited CaP coating (thickness: 2 ± 1 µm) was mainly composed of nano-needles of octacalcium phosphate. We demonstrated its mechanical stability after screwing and unscrewing the dental implant in an artificial jawbone. Then, we showed that we can reach a high copper incorporation rate (up to a 27% Cu/(Cu+Ca) molar ratio) in this CaP coating by using an ionic exchange post-treatment with copper nitrate solution at different concentrations. The biological properties (antibiofilm activity and cytotoxicity) were tested in vitro using a model of mixed bacteria biofilm mimicking peri-implantitis and the EN 10993-5 standard (direct contact), respectively. An efficient copper-doping dose was determined, providing an antibiofilm property to the coating without cytotoxic side effects. By combining the electrodeposition and copper ionic exchange processes, we can develop an antibiofilm calcium phosphate coating on dental implants with a tunable thickness and phases content.

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 1.6µm, 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 (∼2µm) 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.