Transmittance Characteristics of Dimethacrylate Resin Based Dental Composites

Abstract

Background: The transmission of light through dental composites is a major factor responsible for photo activation polymerisation and optical properties of these materials. The extent of the light transmission depends on their formulations.Objectives: The purpose of this study was to determine the transmittance of dental resin-composites and investigate the effect of material thickness and light wavelength.Methods: Four photo-cured disc samples (Φ20mm) with different material thicknesses (ranging from x=0.11mm to x=1.46mm) of three different nanohybrid dental resin–composites (Regular, Flowable and Sealant) of the same shade, A3 and matrix but different filler loading were prepared. Transmittance measurements (n=3) were made using an Ocean Optics USB 4000 fibre optic Spectrometer operated by a Spectra Suite software. Data were analysed by One-way analysis of variance (ANOVA) combined with Tukey multiple test.Results: Differences were found in transmittance values as both material thickness and light wavelength increases. Transmittance (T) increase significantly (P<0.05) with increasing wavelength and decrease with increasing thickness. Linear regression analysis of In (T)with material thickness for light wavelength, gave R2 values ranging from 0.81 to 0.99. Correlation of attenuation coefficient with light wavelength for the materials indicated significant correlation (p<0.05, r =0.94) with Grandio Seal but not with Grandio (p>0.05, r=0.77) and Grandio Flow (p>0.05, r =0.79).Conclusions: The significant differences in the transmittance with increasing light wavelength and material thickness of the materials may affect their clinical appearance.