Changes on the color parameters of air-abraded resin composite exposed to different colored beverages.

AIM: To evaluate the effect of prophylaxis using sodium bicarbonate and colored beverages on the color parameters of a resin composite. METHODS: Eighty specimens (Z350-3M ESPE) were randomly allocated into eight groups (n = 10), according to the combination of staining solution (artificial saliva, cola, red wine, or coffee) and air-powder abrasion with sodium bicarbonate (either performed or not performed). Specimens were immersed in the staining solution for 48 h (two 24-h cycles). Color evaluation was based on the CIELab system. Two measurements were carried out using a spectrophotometer (Commission Internationale de L'Eclairage L* a* b* system) before and after the immersion period. Final measurement data were analyzed by two-way anova/Tukey's test, and comparisons were made between initial and final measurements by anova/Dunnett's test, with a 5% significance level. RESULTS: Most comparisons between initial and final measurements were statistically significant. Red wine and coffee significantly affected the color parameters (L*, b*, and ΔE). However, only coffee significantly increased a* values. When compared with untreated surfaces, air-powder abrasion resulted in alterations of b* and a* parameters, but did not affect L* and ΔE. CONCLUSIONS: Both colored beverage solutions and air-powder abrasion can affect the color of composite resin restorations.

Morphologic texture characterization allied to cigarette smoke increase pigmentation in composite resin restorations.

STATEMENT OF THE PROBLEM: The staining effect of tobacco smoke on resin color is clinically observed. However, there is no evidence determining whether this staining is increased on texturized surfaces or if the color change is superficial and can be removed by repolishing procedures. OBJECTIVE: To evaluate the effect of tobacco smoke on the color of a composite with smooth or texturized surfaces, before and after repolishing. MATERIALS AND METHODS: Forty composite specimens were allocated into four groups (N = 10): Smooth surface not exposed (G1) and exposed to tobacco smoke (G2), texturized surface not exposed (G3), and exposed to tobacco smoke (G4). During 21 days, G2 and G4 were daily exposed to the smoke from 20 cigarettes. Color measurements were carried out at baseline, after 21 days, and after repolishing. Variables L* (luminosity), b* (blue-yellow), and DeltaE (total color change) were statistically analyzed (repeated measures analysis of variance/Tukey). RESULTS: Texturized and smooth specimens presented similar luminosity at baseline. Tobacco smoke significantly reduced L* in G2 and G4, and increased b* in G4. After repolishing, L* increased and b* reduced in stained groups, but values continued to be different from baseline ones. Repolishing significantly reduced DeltaE, but values from stained groups were still greater than that from unstained groups. CONCLUSION: Tobacco smoke changes the color of composite, and surface texture can increase the staining. Repolishing reduces superficial staining, but this procedure may not return the composite to baseline color. CLINICAL RELEVANCE: Smokers that will receive anterior composite restorations should be warned about the negative cosmetic effect of the smoking habit on the color of restorations.

Sistemas matrizes para restauraçöes de cavidades classe II: vantagens e limitaçöes / Matrix systems for restorations in class II cavities: advantages and limitations

Os sistemas matrizes säo dispositivos que substituem uma ou mais paredes ausentes em uma cavidade, possibilitando a reconstruçäo correta da anatomia dental, através de uma restauraçäo. Säo inúmeros os tipos existentes, cada um com suas características específicas, vantagens, limitaçöes e indicaçöes de uso. Conhecendo os diferentes tipos de sistemas matrizes e suas aplicaçöes, o profissional de Odontologia tem seu trabalho facilitado. Assim o objetivo deste trabalho é apresentar uma revisäo de literatura sobre os diferentes sistemas matrizes que podem ser utilizados em restauraçöes de cavidade classe II em dentes posteriores, ficando sua escolha e aplicaçäo na dependência do operador