Effect of bleaching treatments on the mechanical behavior of the dentin matrix and on the collagen biodegradation by endogenous collagen protease

• Grant number: 21/13964-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2022
• End date: March 31, 2023
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Roberta Tarkany Basting Höfling
• Grantee: Larissa Barroso Junquera
• Host Institution: Centro de Pesquisas Odontológicas São Leopoldo Mandic. Faculdade São Leopoldo Mandic (SLMANDIC). Sociedade Regional de Ensino e Saúde S/S Ltda (SRES). Campinas , SP, Brazil

Abstract

This study aims to evaluate the mechanical behavior of the dentin matrix when submitted to different bleaching treatments - through the evaluation of the elastic modulus and maximum tensile strength - and to associate it with the changes in collagen mass and collagen biodegradation by endogenous protease. Thirty-six dentin collagen matrices (demineralized beams) will be prepared to receive the bleaching treatments (n = 12): absence of bleaching treatment (control group), bleaching treatment with 10% carbamide peroxide for at-home use (Opalescence PF 10 % / Ultradent / 8 hours a day / 14 days) and bleaching treatment with 40% hydrogen peroxide for in-office use (Opalescence Boost / Ultradent / 40 minutes per session / 3 sessions). The dentin matrices will be evaluated regarding their elastic modulus and mass (before and after treatments) with the storage of the specimens in SBF (solution body fluid) during intervals of bleaching procedures. The solution collected during storage will be evaluated for its hydroxyproline release to analyze collagen degradation by endogenous protease. The dentin matrices will be submitted to the evaluation of maximum tensile strength to analyze the effect of bleaching treatments on the mechanical behavior of dentin. The results will be evaluated using two-way ANOVA (for the analysis of elastic modulus and mass) followed by Tukey's test, and by one-way ANOVA (collagen degradation by endogenous protease and maximum tensile strength), adopting the 5% level of significance (pÂ0.05). If there is no homogeneity of variation, the nonparametric tests will be used.(AU)