The objectives of this study were to evaluate the effect of surface roughness on the surface color and translucency of the composite resins.Two composite resins (Esthet-X, Dentsply, Milford, USA and Charisma, Kulzer, Domagen, Germany) were used to investigate the surface color. Charisma was used to investigate the translucency. 40 disc samples (diameter: 8 ㎜, thickness: 5 ㎜) were made by each product to measure the surface color. Polymerized each sample' s one side was treated by Sof-Lex finishing and polishing system (Group C, M, F, SF). 40 disc samples (diameter: 6 ㎜, thickness: 1 ㎜) were prepared to measure the opacity. 1 ㎜ samples were ground one side with #600, #1000, #1500 and #2000 sandpapers. CIE L*a*b* values of each 5 ㎜ thickness samples, and XYZ values of 1 ㎜ thickness samples on the white and black background were measured with spectrophotometer (Spectrolino, GretagMacbeth, Regensdorf, Switzerland).Mean surface roughness (Ra) of all samples before and after surface treatment was measured using the Surface Roughness Tester SJ-301 (Mytutoyo, Tokyo, Japan).Regardless of type and shade of the composite resin, L* values measured in group C were higher than others (p < 0.05), and L* value decreased as the Ra value decreased except B3 shade of Esthet-X. But there were no significant difference in a* values among groups. In control group and SF, highest b* values were measured (p < 0.05), except B1 shade of Esthet-X.Contrast ratio decreased as the Ra value decreased (p < 0.05).With the above results, difference of surface roughness has influence on surface color and translucency of dental composite resins. [J Kor Acad Cons Dent 31(4):312-322, 2006]

This study was done to evaluate the reliability of the digital color analysis system (ShadeScan, CYNOVAD, Montreal, Canada) for dentistry.Sixteen tooth models were made by injecting the A2 shade chemical cured resin for temporary crown into the impression acquired from 16 adults. Surfaces of the model teeth were polished with resin polishing cloth. The window of the ShadeScan handpiece was placed on the labial surface of tooth and tooth images were captured, and each tooth shade was analyzed with the ShadeScan software. Captured images were selected in groups, and compared one another.Two models were selected to evaluate repeatability of ShadeScan, and shade analysis was performed 10 times for each tooth.And, to ascertain the color difference of same shade code analyzed by ShadeScan, CIE L*a*b*values of shade guide of Gradia Direct (GC, Tokyo, Japan) were measured on the white and black background using the Spectrolino (GretagMacbeth, USA), and Shade map of each shade guide was captured using the ShadeScan.There were no teeth that were analyzed as A2 shade and unique shade. And shade mapping analyses of the same tooth revealed similar shade and distribution except incisal third.Color difference (ΔE*) among the Shade map which analyzed as same shade by ShadeScan were above 3. Within the limits of this study, digital color analysis instrument for dentistry has relatively high repeatability, but has controversial in accuracy. [J Kor Acad Cons Dent 33(4):352-368, 2008]

This study analyzed the influence of dental adhesive/primer on the bond strength between indirect resin composite and the resin cement.Seventy disc specimens of indirect resin composite (Tescera Dentin, Bisco) were fabricated. And bonding area of all specimens were sandblasted and silane treated for one minute. The resin cements were used with or without application of adhesive/primer to bonding area of indirect resin restoration: Variolink-II (Ivoclar-Vivadent): Exite DSC, Panavia-F (Kuraray): ED-Primer, RelyX Unicem (3M ESPE): SingleBond, Duolink (Bisco): One-step, Mulitlink (Ivoclar-Vivadent): Multilinh Primer.Shear bond strength was measured by Instron universal testing machine. Adhesive application improved shear bond strength (p < 0.05). But Variolink II and Panavia-F showed no statistically significant difference according to the adhesive application.With the above results, when resin inlay is luted by resin cement it seems that application of dental adhesive/primer is necessary in order to improve the bond strength. [J Kor Acad Cons Dent 33(5):419-427, 2008]

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In this study we evaluated the influence of both the thickness of residual enamel and the color of the composite resins applied to lingual surface on the labial surface color.Background plates were made by randomly (A1, A2, A6D, B1, B2, B3, C1, C2, C6D) selected colors of Filtek Supreme (3M ESPE, St. Paul, U.S.A.) composite resin .Crown portion of 9 maxillary central incisors were cut off and embedded with acrylic resin except labial surface. Samples of average thickness of 2.2 mm were obtained after cutting it in a thickness of 2.5 mm from the labial surface and sandpaper polish.The shade of composite resin background was measured using Spectrophotometer (Spectrolino � , GretagMacbeth, Regensdorf, Switzerland). And CIE L*a*b* value of 2.2 mm thickness tooth samples were measured on the 9 composite resin backgrounds. And then, the cutting side of tooth samples was ground to the extent of 1.9 mm, 1.6 mm, 1.3 mm, 1.0 mm and placed on composite resin backgrounds and measured L*a*b* values with the same method.In all samples, L* value and b* value seemed to have a tendency of decreasing as thickness of tooth sample becomes thinner regardless of background colors (p < 0.05). But, a* value didn't show the significant differences depending on the thickness. [J Kor Acad Cons Dent 34(4): [309][310][311][312][313][314][315][316][317][318][319][320][321][322][323] 2009]