ABSTRACT
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.
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.
Subject(s)
Humans , Dental Bonding , Pit and Fissure Sealants , Saliva/chemistry , Benzhydryl Compounds , PhenolsABSTRACT
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.
Subject(s)
Dental Bonding , Pit and Fissure Sealants , Saliva/chemistry , Benzhydryl Compounds , Humans , PhenolsABSTRACT
OBJECTIVES: Considering the enamel chemical structure, especially carbonate band, which has a major role in the caries prevention, the objective of the present study was to assess the chemical alterations on the enamel irradiated with CO(2) laser by means of FTIR spectroscopy and SEM analysis. DESIGN: The enamel surfaces were analysed on a spectrometer for acquisition of the absorption spectrum relative to the chemical composition of the control sample. The irradiation was conducted with a 10.6-µm CO(2) laser (0.55W, 660W/cm(2)). The carbonate absorption band at 1600-1291cm(-1) as well as the water absorption band at 3793-2652cm(-1) was measured in each sample after the irradiation. The water band was measured again 24-h after the irradiation. The band area of each chemical compound was delimited, the background was subtracted, and the area under each band was integrated. Each area was normalized by the phosphate band (1190-702cm(-1)). RESULTS: There was a statistically significant decrease (p<0.05) in the water content after irradiation (control: 0.184±0.04; irradiated: 0.078±0.026), which increased again after rehydration (0.145±0.038). The carbonate/phosphate ratio was measured initially (0.112±0.029) and its reduction after irradiation indicated the carbonate loss (0.088±0.014) (p<0.05). CONCLUSION: The 10.6-µm CO(2) laser irradiation diminishes the carbonate and water contents in the enamel after irradiation.
