A influência da fotoativação na polimerização de resinas compostas convencionais e bulk-fill no grau de conversão de monómeros e microdureza

: uma revisão sistemática

Abstract

Introduction: Resin composites are widely used in restorative dentistry due to their mechanical properties, aesthetics, and biocompatibility. The success of restorations depends on the material's microstructure and proper photopolymerization. Objective: This systematic review aimed to evaluate the degree of conversion and microhardness of conventional and bulk-fill composite resins during photopolymerization. Materials and methods: A bibliographic review was performed on Pubmed, Scopus and Web of Science using the following key terms: resin composites AND degree of conversion AND microhardness AND light curing unit OR photoinitiator OR light curing distance OR polymerization distance OR exposure time. The search included articles in English language between January 2010 and December 2023, that related different types of photoactivation with the degree of monomers conversion and microhardness in conventional and bulk-fill resin-matrix composites. Results: Studies show that the degree of conversion and microhardness decrease with depth and shorter exposure time. A linear correlation between the degree of conversion, microhardness, and refractive index was observed. Different resin-matrix composites were affected by the emission spectra and irradiance of light-curing units, inorganic particles, also alternative photoinitiators increased microhardness on the surface with wide range lights, however this was not observed on the bottom due to lower violet light amount. Similar or higher conversion degree and microhardness values were obtained with 1200 mW/cm² compared to 3600 mW/cm². The polymerization distance affects the physical properties and durability of the resin composites. Conclusion: Microhardness reflects polymerization efficiency due to its correlation with the degree of conversion. Conventional and bulk-fill resin composites have similar microstructures but differ in photoinitiator chemistry, affecting the choice of light curing units needed for bulk-fill composites.

Date of Award	30 Jul 2024
Original language	Portuguese
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Rita Fidalgo-Pereira (Supervisor), Anna Moura (Co-Supervisor) & Pedro Lopes (Co-Supervisor)