Document Type : Original Article(s)
Authors
1
Dental Materials Research Center and Department of Operative Dentistry, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran
2
Department of Polymer Science, Iran Polymer and Petrochemical Institute, Tehran, Iran
3
Department of Oral Medicine, School of Dentistry, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
4
Department of Operative Dentistry, School of Dentistry, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
Abstract
Statement of Problem: The degree of conversion depends on the material composition, light source properties, distance from light source, light intensity, curing time, and other factors such as shade and translucency.Objectives: In the present study, we evaluated the effects of different light- curing modes and shades of methacrylate and silorane-based resin composites on the degree of conversion of resin composites (DC).Materials and Methods: The methacrylate-based (Filtek Z250, 3M, ESPE) and low-shrinkage silorane-based (Filtek P90, 3M, ESPE) resin composites were used in three groups as follows: group 1-Filtek Z250 (shade A3), group 2-Filtek Z250 (shade B2), and group 3-Filtek P90 (shade A3). We used a light-emitting diode (LED) curing unit for photopolymerization. 10 samples were prepared in each group to evaluate the degree of conversion; 5 samples were cured using soft-start curing mode, and the other 5 were cured using standard curing mode. The DC of the resin composites was measured using Fourier Transform Infrared Spectroscopy (FTIR). The data were analyzed using Kruskal Wallis and one- way ANOVA statistical tests.Results: The degree of conversion of silorane-based resin composite was 70- 75.8% and that of methacrylate-based resin composites was 60.2 - 68.2% (p = 0.009). The degree of conversion of the composite with brighter colour (B2) was statistically more than the darker composite (A3). Higher degree of conversion was achieved applying the standard curing mode.Conclusions: The results of the study showed that the colour and type of theresin composite and also the curing mode influence the degree of conversion ofresin composites.Key words: Degree of Conversion, Methacrylate-Based Resin Composites, Silorane-Based Resin Composites, Soft-Start Curing
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