Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
J Dent. 2012 Dec;40 Suppl 2:e77-82. doi: 10.1016/j.jdent.2012.08.016. Epub 2012 Sep 3.
The purpose of this study was to evaluate the light transmission characteristics of dentine and resin composites with different thickness.
Disks of bovine dentine and three resin composites (Estelite Σ, Beautifil II and Clearfil Majesty) of OA2 shade were prepared with various thicknesses (0.5, 1.0 and 2.0mm). Using a goniophotometer, the distribution graphs of the light transmission intensity of each specimen were obtained, and diffusion factor (DF) as an indicator for a diffuse transmission property and peak-gain (G0) for a straight-line transmission property were calculated. Their colors were measured on black and white backings using a reflection spectrophotometer to calculate translucency parameter (TP). The data of each value (G0, DF and TP) were analyzed by two-way ANOVA and Dunnett's T3 for post hoc test (p=0.05). Regression analyses were used to determine the correlation between G0, DF, TP values and the thickness.
Regardless of the thickness, dentine had lower TP values than the resin composites. 0.5 mm-thick specimens of dentine and resin composite produced various G0 and DF values, with dentine exhibiting significantly lower G0 and higher DF than the resin composites (p<0.05), whereas with the 1.0 and 2.0mm-thick specimens, they were closely aligned. For dentine, G0 and DF increased in inverse proportion to the thickness (G0: R(2)=0.962, p<0.001; DF: R(2)=0.891, p<0.001).
Dentine had different light transmission characteristics from resin composite, depending on the thickness.
Dentine has different light transmission characteristics (straight-line and diffusion) from resin composite, depending on thickness. Resin composite restoration might be different to accurately reproduce light transmission characteristics of dentine substrate.
本研究旨在评估不同厚度的牙本质和树脂复合材料的透光特性。
制备厚度分别为 0.5、1.0 和 2.0mm 的牛牙本质和三种树脂复合材料（Estelite Σ、Beautifil II 和 Clearfil Majesty）的圆盘。使用分光光度计获得每个标本的光传输强度分布图谱，并计算漫射因子（DF）作为漫射传输特性的指标和峰值增益（G0）作为直线传输特性的指标。使用反射分光光度计在黑白衬底上测量它们的颜色，以计算不透明度参数（TP）。使用双向方差分析和 Dunnett's T3 进行事后检验（p=0.05）对每个值（G0、DF 和 TP）的数据进行分析。使用回归分析确定 G0、DF、TP 值与厚度之间的相关性。
无论厚度如何，牙本质的 TP 值均低于树脂复合材料。牙本质和树脂复合材料的 0.5mm 厚标本产生了不同的 G0 和 DF 值，牙本质的 G0 值明显低于树脂复合材料，DF 值明显高于树脂复合材料（p<0.05），而 1.0 和 2.0mm 厚的标本则非常接近。对于牙本质，G0 和 DF 与厚度成反比增加（G0：R²=0.962，p<0.001；DF：R²=0.891，p<0.001）。
牙本质的透光特性与树脂复合材料不同，这取决于厚度。
牙本质的透光特性（直线和扩散）与树脂复合材料不同，这取决于厚度。树脂复合材料修复体可能会有所不同，无法准确再现牙本质底物的透光特性。
