Synthesis of new reparative biomaterial, evaluation of calcium silicate materials and analysis of the effect of the application of bioglass in the treatment of dentin and in the coating of Gutta percha in the interaction with bioceramic root canal sealers

Abstract

Considering the experience of our research group of more than twenty years with studies of properties and development of biomaterials, this project aims to develop tricalcium silicate repair biomaterial, and define protocols for dentin and gutta-percha treatment aiming at better sealing after using bioceramic root canal sealers. Material properties under different conditions will be also evaluated. The study will be divided into four parts: Part A: Development of an low-cost repair biomaterial. Physicochemical properties will be evaluated using conventional methodologies and computed microtomography (micro-CT). The experimental cement will be compared to MTA Angelus. The physicochemical properties will be evaluated based on the ISO 6876/2012 standard. The volumetric change and the porosity of the cements will be evaluated using micro-CT. Part B: The Laboratory of Vitreous Materials (LaMaV - UFSCar) developed a bioglass, called F18, with high bioactivity. The effect of dentin treatment (bioglass suspension at different concentrations, PBS and distilled water as control) on dentin and cement/dentin interface will be evaluated. Bovine dentin blocks will be used for evaluation by SEM and X-ray energy dispersion spectroscopy (EDS). The cement/dentin interface will be evaluated after contact with Bio-C Sealer bioceramic sealer (Angelus, Brazil) or resinous AH Plus (Dentsply, Switzerland). Dentin/cement blocks will be scanned in micro-CT (9 µm resolution). The bond strength of the filling material with the dentin will be evaluated through the push-out test and microshear bond strength. Part C: The incorporation/coating of gutta percha with bioglass will be evaluated. The incorporation of bioglass at different concentrations (2.5, 5 and 10%) to gutta-percha will be carried out. The dip coating technique will also be evaluated by immersing gutta-percha in a suspension of bioglass particles (2.5, 5 and 10%). Gutta-percha blocks will be used to evaluate the effect of gutta-percha treatments. The gutta-percha/cement interface will be evaluated after contact with endodontic sealers. Obturation will be performed with Bio-C Sealer or AH Plus associated with gutta-percha in dentin tubes and subsequent evaluation by micro-CT and push-out analysis. Part D: This study aims to evaluate the effect of immersion media (distilled water, phosphate buffered saline (PBS) and in vivo model in subcutaneous tissue of rats) on the physicochemical properties, biocompatibility and bioactivity of endodontic cements. Analyzes of volumetric change and porosity of materials will be performed in micro-CT. Cell viability (MTT and Neutral Red) and bioactivity (alkaline phosphatase activity and alizarin red color) will be determined. The data obtained for each evaluation will be submitted to appropriate statistical tests, with a significance level of 5%. (AU)