How light irradiance and curing time affect monomer conversion in light‐cured resin composites

Abstract

We tested the hypothesis that the degree of conversion of a light-cured dental composite relates to the calculated (s x mW cm-2 = mJ cm-2) rather than to the irradiance value (mW cm-2) of the light source. Two light-curable composite resins were cured with three different light irradiance values over different curing times. The specimens tested were 2, 4 or 6 mm thick, and the degree of conversion values were measured with Raman spectroscopy on the top and the bottom surfaces of the specimens. The highest conversion value of one of the materials was just below 60%, while the maximal conversion value of the other material was just below 65%. That difference in conversion values could be related to differences in monomer systems used in the two composites. By considering light energy per square centimeter (J cm-2) rather than light irradiance (mW cm-2), we found that equivalent energy values gave similar conversion values for a certain sample thickness. From these findings, we conclude that our experimental results support our hypothesis.

Continuous and gradual photo-activation methods: influence on degree of conversion and crosslink density of composite resins

“…These results indicate that all the tested photo-activation methods were able to cure appropriately the Filtek TM Z-250 and Filtek TM Supreme XT (both 3M Espe) composites, despite the differences (e.g., PD) among them. These results are similar to those found by other studies [2,6,13,26,34,54,55].…”

Influence of ceramic thickness on mechanical properties and polymer structure of dual-cured resin luting agents

“…For light-cured resin materials, the reduction of energy density of light irradiation can decrease the degree of conversion (DC) and mechanical properties [1][2][3][4], which limits the application of light-cured resin luting agents in the bonding of thicker esthetic restorative materials.…”

Avaliação do grau de conversão de resinas compostas fotoativadas em diferentes tempos e potências

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