Effects of lithium disilicate thickness and complementary photopolymerization on the degree of polymer conversion of dual and light-cured resin cements.

• Grant number: 24/10694-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2024
• End date: April 30, 2025
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: José Maurício dos Santos Nunes Reis
• Grantee: Rafael Ragnolli Guimarães
• Host Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

This study aims to evaluate the degree of polymer conversion after photoactivation by transillumination of the interface between resin cements and lithium disilicate glass-ceramic with variations in thickness and photoactivation method. Discs (Ø 7.75 mm) of IPS e.max CAD MT-A2 will be obtained, polished, crystallized, and prepared in three thicknesses: 0.5 mm; 1.0 mm; and 1.5 mm (n=20/thickness). For the analysis of the degree of conversion, samples of different thicknesses will be randomly allocated into groups, according to the resin cement and photoactivation method (n=5): (1) dual/standard; (2) dual/standard+complementar; (3) photoactivated/standard; or (4) photoactivated/standard+complementar. The samples will be placed over the resin cements using a matrix to standardize the cement thickness and then subjected to two photoactivation protocols: following the manufacturer's instructions (standard) or with standard protocol followed by complementary photoactivation cycles. After storage at 37°C for 24 h, the degree of conversion of each experimental group will be measured using Fourier transform infrared spectroscopy (FTIR). The quantitative data will be subjected to normality and homoscedasticity tests to select appropriate statistical tests for the analyses, adopting a significance level of 95%.