Bioactive Sphene Coatings for Dental Implant Applications Rivestimenti bioattivi a base di sphene per impianti dentali

Over the last few decades, due to the aging of the population, prolonged life expectancy and increased demand for esthetic dental procedures, there is an increasing request for dental implant treatment for the replacement of missing teeth. In addition, in presence of an inadequate amount of bone for implant positioning, bone regeneration procedures are required. Among various strategies, which are currently being investigated, synthetic biocompatible three-dimensional structures, known as “scaffolds”, produced using different additive manufacturing technologies are attracting growing attention for use in bone tissue regeneration, as personalized bone scaffolds can be designed to fit specific bone defects. Successful use of bioactive ceramics, as coating materials for dental implants as well as bone substitutes, has been reported. In particular, sintered hydroxyapatite (HA) has been extensively employed in clinical dental practice. However, its low fracture toughness and the occurrence of delamination at the interface with titanium substrates have significantly limited the scope of clinical applications. More recently, a new category of bioactive ceramics, i.e. silicate-based ceramics, has received great attention, due to their remarkable bioactivity and good mechanical properties. The primary aim of the current project is to develop and test in vitro and in vivo a specific bioactive silicate-based ceramic, sphene (CaTiSiO5), as coating material for dental implants. Sphene coatings will be prepared using a preceramic polymer containing nanosized active fillers as precursors for the formation of the desired ceramic phase. Coating will be applied by airbrushing, and the samples will undergo heat treatment, in order to transform the precursors into a ceramic coating. Once the sphene-coated implants will be prepared, they will be fully characterized in terms of microstructure analysis, crystalline phase assemblage, physicochemical properties, effect on mesenchymal stem cell behavior in vitro, and, finally, osseointegration in a rat model. Secondary aim of this project consists in the production and characterization of sphene ceramic scaffolds to be utilized as bone substitutes for bone tissue regeneration. These scaffolds will be fabricated by direct ink writing using a preceramic polymer and nano sized active fillers. The samples will be then characterized, and a particular attention will be given to investigating in vitro cytocompatibility and osteoconductive properties, prior to in vivo study using rat critical size calvarial defect model.