en ترمیمی Cosmetic and Restorative Dentistry پژوهشي Research Objectives <p> The purposes of this study were: (1) to determine the light transmission characteristics (straight-line and diffusion transmission) of bulk-filled and layered resin composites, and (2) to evaluate the effect of layering filling on translucency and color appearance of resin composites.</p>Methods <p> Three light-cured resin composites (EsteliteΣ, Tokuyama Dental Beautifil II, Shofu and Clearfil Majesty, Kuraray Medical) in A2 and OA2 shades were used in this study. 2<img alt="AWT IMAGE" src="webfiles/images/transparent.gif" width="4" height="1" >mm-thick resin composite discs were prepared by two methods bulk filling technique (2<img alt="AWT IMAGE" src="webfiles/images/transparent.gif" width="4" height="1" >mm filling at one time), layering technique (two layers each 1<img alt="AWT IMAGE" src="webfiles/images/transparent.gif" width="4" height="1" >mm thickness). The transmitted light intensity of each resin composite disc was measured using a goniophotometer, and diffusion factor (DF), an indicator for diffuse transmission property, and peak gain (G0) for straight-line transmission were calculated from the light distribution graphs. Color was measured according to the CIELAB color scale on a spectrophotometer, and the translucency parameter (TP) and color difference (Δ<i>E</i>^*) between bulk-filled and layered specimens were calculated. The data were statistically analyzed using three-way ANOVA, and Dunnett's T3 and <i>t</i>-test for post-hoc test.</p>Results <p> Three-way ANOVA revealed that the layered specimens had significantly lower G0 values and higher DF values than the bulk-filled specimens, and significantly reduced TP values. The color differences (Δ<i>E</i>^*) ranged from 1.07 to 1.85 between the bulk-filled and layered specimens.</p>Significance <p> Resin composite placed in layers exhibited reduced straight-line light transmission and increased diffusion transmission compared with bulk-filled resin composite. The layering technique affected the translucency and color rendition of resin composite. </p><hr><p></p><p> <strong> Source: </strong>Dental Materials </p><p><a href="http://www.demajournal.com/article/S0109-5641(11)00869-4/abstract" target="_blank"><font color="#0000cc">  Full text </font></a></p> Layering technique, Resin composite, Diffuse light transmission, Straight-line light transmission, Translucency, Color appearance 0 0 http://idai.ir/browse.php?a_code=A-10-32-257&slc_lang=en&sid=1 • Kanako • Horie 10031947532846001033 10031947532846001033 Yes • Masatoshi • Nakajima 10031947532846001034 10031947532846001034 No • Keiichi • Hosaka 10031947532846001035 10031947532846001035 No • Kimisuke • Kainose 10031947532846001036 10031947532846001036 No • Azusa • Tanaka 10031947532846001037 10031947532846001037 No • Richard • M. Foxton 10031947532846001038 10031947532846001038 No • Junji • Tagami 10031947532846001039 10031947532846001039 No