The contrast ratio, light reflectivity, scattering coefficient, and absorption coefficient of four composites and an unfilled resin were calculated algebraically from reflection spectrophotometric data using Kubelka's equations. The correlation coefficient between calculated and experimental values of contrast ratio was 0.9996. Values of infinite optical thickness ranged from 4.19 to 6.70 mm.

Light reflectivity, scattering coefficient, absorption coefficient, infinite optical thickness, and contrast ratio were determined in white light, for seven shades of a conventional composite and five shades of a microfilled composite, from reflection spectrophotometric data using Kubelka's equations. Significant differences among shades were observed for each property. Values of infinite optical thickness ranged from 2.97 to 5.90 mm among the shades studied.

These results suggest that the MBL2 gene is related to the pathogenesis of dental caries.

The optical properties of seven shades of a conventional composite and five shades of a microfilled composite were determined from reflection spectrophotometric data with Kubelka's equations. Scattering and absorption coefficients decreased and values of infinite optical thickness increased as wavelength increased from 405 to 700 nm. Reflectivity curves were determined.

The aim of this study was to examine defect depths and volumes at the resin composite-dentin (R/D) interface after air polishing with different particles and spray angles. Samples were 54 dentin specimens that were formed in saucer-shaped cavities filled with resin composite. Each specimen was air polished with either sodium bicarbonate (NaHCO3) or one of two glycine (Gly) powders. The air polisher was set at angles of 90° to the interface and at 45° to the interface from both the dentin and resin composite sides. Air polishing with Gly powder produced defects with less depth and volume than NaHCO3 powder (p < 0.05). Air polishing with a spray angle of 45° to the interface from the resin composite side produced fewer defects (p < 0.05) than polishing from the dentin side. Air polishing to the R/D interface from the resin composite side produced fewer defects to the interface because the hardness of the resin composite was higher than that of dentin.