Effect of pre-heating resin composite and light-curing units on monomer conversion

Long-Term Surface Hardness and Monomer Conversion of a Nanofilled and a Microhybrid Composite Resin

“…[28][29][30] Although both organic and inorganic phases of the resin are capable of influencing the material behavior, the amount and characteristics of the filler particles are the most important factors for improving the mechanical properties of the composites. 10,[30][31][32] The study developed by Kim et al 31 showed that flexural strength, flexural modulus, hardness and fracture resistance of composite resins were significantly influenced by the morphology and content of filler particles.…”

“…An inadequate polymerization may cause decreased physical properties, solubility in the oral environment and more susceptibility to microleakage, which can cause recurrent caries and pulp irritation. 10,17,25,32,[34][35][36] The degree of conversion is defined as the percentage of reacted C = C aliphatic bonds of dimethacrylate monomer present in the polymeric matrix of the resin, and the extent of this response is directly related to the clinical success of restorations. 37 Ideally, dental composites should have all of its monomer converted into polymer during the polymerization reaction.…”

“…3,14,15,38,39 These values agree with the degree of conversion observed in this study that showed an average of 55.1% (nanofilled resin) and 57.1% (microhybrid resin) and this result is in accordance with those obtained in other studies that used the FT-IR spectroscopy to measure the degree of conversion of resin composites. 32,39,40 Some of the factors that determine degree of conversion of composite resins are: chemical composition of the material, curing time, power density and distance of the photocuring unit tip. 3,14,32,33 In this study, variables related to polymerization were standardized, so that possible differences in materials could be attributed solely to differences in composition between them.…”

“…32,39,40 Some of the factors that determine degree of conversion of composite resins are: chemical composition of the material, curing time, power density and distance of the photocuring unit tip. 3,14,32,33 In this study, variables related to polymerization were standardized, so that possible differences in materials could be attributed solely to differences in composition between them. Thus, it is likely that the similar organic matrix of the tested composite resins have determined equivalent degrees of conversion to both of them, while the difference in hardness between them must have occurred due to the characteristics of the filler particles.…”

Shore hardness behavior of light‐cured dental composite resin filled with TiO2 nanoparticles

“…One of the most used indirect procedures to estimate the degree of curing of the dental composite resin is the hardness test, [14]. Hardness gives useful information on the depth of curing when such measurements are performed on the top and bottom surfaces of cured samples.…”