Osteointegrative functionalization of dental implants: a new synergic approach

Titanium and its alloys have been widely used for dental implants due to their excellent combination of strength-to-weight ratio, excellent corrosion resistance and biocompatibility [1]. In order to improve osseointegration, the titanium surface is generally functionalised. A typical methodology of surface modification, able to efficiently change the surface chemistry of a metallic implant, is the coating of the titanium substrates with layers of bioactive calcium phosphate ceramics (CPCs) [2]. Moreover, titanium implants are usually processed in order to increase the surface roughness in a controlled way: sandblasting and/or chemical etching are approaches commonly used. With the aim of improving the adhesion strength between the Ti substrate and the CPC layer, the insertion of dense and compact ceramic interlayers is reported to be useful [1]. Indeed, they improve the film to implant adhesion both reducing the thermal mismatch between the metal and the calcium layer and increasing the amount of -OH sites available. Among various ceramics, crystalline titania (TiO2) has been extensively used as an inter-layer thanks to its well-known biocompatibility and bioactivity [1]. In this work, three types of Ti substrates (machined, sandblasted, and sandblasted/acid etched) were initially coated with a crystalline, dense and compact TiO2 inter-layer via MOCVD. Then, a discontinuous and homogenously spread CPC top-layer was obtained by means of spray pyrolysis technique. Finally, a thermal treatment at high temperature was carried out in order to crystallize the final composite material. Preliminary investigation on the influence of the pristine substrate morphology on TiO2 crystalline structure, morphology, surface wettability and in vitro acellular bioactivity is here presented. Moreover, the CPC/TiO2 composite material was also characterized by means XRD, SEM and release tests.