Resumo Selantes dentários são importantes para a prevenção de lesões de cárie desde que tenham boa resistência ao cisalhamento. O objetivo deste trabalho foi avaliar a resistência ao cisalhamento (SBS), de dois selantes em esmalte contaminado e não contaminado com saliva, com e sem uma camada adesiva intermediária sob o selante. Noventa superfícies de esmalte de terceiros molares humanos foram planificadas e divididas aleatoriamente em 6 grupos (n=15): F (controle): selante Fluroshield(tm); EWB (controle): Embrace(tm) WetBond(tm); SB/F: sistema adesivo Single Bond + F; SB/EWB, s-SB/F and s-SB/EWB. Nos grupos s-SB/F e s-SB/EWB, a contaminação do esmalte condicionado foi obtida com 0,01 mL de saliva humana fresca durante 20 s. Cilindros de selante foram colocados sobre a superfície do esmalte com e sem uma camada de sistema adesivo intermediária. Os ensaios de cisalhamento foram realizados utilizando uma máquina universal de ensaios (0,5 mm/min). Os dados foram analisados estatisticamente pelo teste de Kruskal-Wallis e Mann-Whitney (?#61537;=0,05). F apresentou valores médios de SBS maiores do que EWB em todas as condições experimentais. O menor valor médio de SBS foi obtido pelo EWB em esmalte contaminado (p<0,05). Em conclusão, uma camada de sistema de adesivo deve ser utilizada antes da colocação do selante, tanto em superfície seca quanto contaminada por saliva. F teve o melhor desempenho em todas as condições experimentais. O selante EWB apresentou resultados insatisfatórios, porém o uso de uma camada adesiva abaixo do selante aumentou sua SBS, mesmo após a contaminação salivar.

Abstract Dental sealants are important for prevention of carious lesions, if they have good shear strength. The aim of this study was to evaluate the shear bond strength (SBS) of two sealants to saliva-contaminated and non-contaminated enamel with and without an intermediate adhesive layer underneath the sealant. Ninety flat enamel surfaces from human third molars were randomly assigned to 6 groups (n=15): F (control): Fluroshield(tm) sealant; EWB (control): Embrace(tm) WetBond(tm); SB/F: Single Bond adhesive system + F; SB/EWB, s-SB/F and s-SB/EWB. In the s-SB/F and s-SB/EWB groups, the acid-etched enamel was contaminated with 0.01 mL of fresh human saliva for 20 s. Sealant cylinders were bonded to enamel surface with and without an intermediate adhesive system layer. The shear tests were performed using a universal testing machine (0.5 mm/min). Data were analyzed statistically by Kruskal-Wallis and Mann-Whitney tests (α=0.05). F presented higher mean SBS than EWB in all experimental conditions. The lowest SBS mean was obtained for EWB on contaminated enamel (p<0.05). In conclusion, an adhesive system layer should be used prior to sealant placement, in both dry and saliva-contaminated enamel. F had the best performance in all experimental conditions. EWB sealant showed very low results, but an adhesive layer underneath the sealant increased its SBS even after salivary contamination.

The aim of this study was to evaluate the effect of industrialised foods and drinks on primary tooth enamel previously eroded with hydrochloric acid (HCl). The crowns of one hundred two specimens were subjected to an erosive challenge with HCl and randomly divided into six groups (n = 17): Chocolate Milk (Toddynho® - Pepsico) - negative control; Petit Suisse Yogurt (Danoninho® - Danone); Strawberry Yogurt (Vigor); Apple puree (Nestlé); Fermented Milk (Yakult® - Yakult); and Home Squeezed Style Orange Juice (del Valle) - positive control. The 28-day immersion cycles for the test products were performed twice daily and were interspersed with exposure of the test substrate to artificial saliva. Measurements of enamel surface microhardness (SMH) were performed initially, after immersion in HCl and at 7, 14, 21 and 28 days of experimentation. A two-way ANOVA, according to a split-plot design, followed by the sum of squares decomposition and Tukey’s test, revealed a significant effect for the interaction between Foods and Drinks and Length of Exposure (p < 0.00001). Orange juice resulted in greater mineral loss of enamel after 28 days. None of the test products was associated with recovery of tooth enamel microhardness.