Opacity and masking effect of the opaque shade composite resins / 대한치과보존학회지

The purpose of this study was to assess the background color-interceptive ability and opacity of opaque shade composites (Universal composite, Filtek Z350, Charisma, Clearfil ST, Palpaque Estelite, Esthet-X, and Metafil Flo). Twenty four background specimens (diameter 5.5 mm, thickness 3.0 mm) with Root dentin Mustard (Bisco, Schaumburg, IL, USA) were made. The CIE L*a*b* value of background specimens was measured by a spectrophotometer (Spectrolino, GretagMacbeth, Regensdorf, Switzerland). Three specimens in every group were filled on the background specimens. The surface color of samples was measured by a spectrophotometer in 3.0 mm and every thickness to 0.5 mm while grinding. The color difference in the background color along with 3.0 mm specimen gauged the masking effect in each thickness while grinding and polishing. The opacity was calculated in 1 mm thick specimens. The opacity was in the decreasing order of Clearfil ST, Metafil Flo, Filtek Z350, Palpaque Estelite, Universal composite, Charisma, and Esthet-X (p < 0.05). As the thickness get reduced, L* value showed decreasing, a* increasing tendency. The surface color difference between pair of the 3.0 mm thick specimen and after grinding in same opaque resin was above 3.3 except Clearfil ST and Metafil Flo. The color difference (DeltaE*) between pair of background specimen and opaque resin builtup specimen showed more than 10.0 regardless kinds and thickness. The variance in opacity characteristics and color of the opaque composites is dependent upon manufacturer. When using the opaque resin, the optical properties of each material must be considered as well as cavity.

The effect of thickness of the provisional crown and fixed partial denture materials on the translucency and masking effect / 대한치과보철학회지

STATEMENT OF PROBLEM: Translucency and masking effect of provisional crown and fixed partial denture materials is an important esthetic consideration. But, provisional resin materials differ substantially in their ability to mask underlying colors. PURPOSE: The purpose of this study was to evaluate the translucency differences of provisional resin materials at various thicknesses and the correlation between the translucency and the masking efficiency. MATERIAL AND METHODS: Two polymethyl methacrylate resins (Jet Tooth Shade, Alike) and three resin composites (Protemp 3 Garant, Luxatemp and Revotek LC) were used. Specimens (n=6) were fabricated from each material in 0.3, 0.5, 0.8, 1.0, 1.5, 2.0 and 3.0 mm thickness. The CIELAB parameters of each specimens were measured using a spectrophotometer. The translucency parameter (TP) values and the masking effect (delta ME*(ab)) values were computed and all data were statistically analyzed by one-way ANOVA and the multiple comparisons Scheffe test. The correlation between the thickness and the TP values and the correlation between the thickness and the delta ME*(ab) values were also evaluated by correlation analysis and regression analysis. RESULTS: The TP values and the delta ME*(ab) values were significantly related to the thickness in all specimens. The TP values were more sensitive to the change of thickness than the delta ME*(ab) values. The order of the translucency by brand was different from the order of the masking effect by brand in all thickness groups. CONCLUSION: Within the limitations of this study, the translucency and masking effect of the provisional resin materials investigated were significantly related to their thickness. The masking effect of provisional resin was correlated with the translucency parameter, but the order of the masking effect by brand was different from the order of the translucency parameter.