Tensile bond strength of self-etching versus total-etching adhesive systems under different dentinal substrate conditions

Abstract

The use of acid etchants to produce surface demineralization and collagen network exposure, allowing adhesive monomers interdiffusion and consequently the formation of a hybrid layer, has been considered the most efficient mechanism of dentin bonding. The aim of this study was to compare the tensile bond strength to dentin of three adhesive systems, two self-etching ones (Clearfil SE Bond -CSEB and One Up Bond F -OUBF) and one total-etching one (Single Bond -SB), under three dentinal substrate conditions (wet, dry and re-wet). Ninety human, freshly extracted third molars were sectioned at the occlusal surface to remove enamel and to form a flat dentin wall. The specimens were restored with composite resin (Filtek Z250) and submitted to tensile bond strength testing (TBS) in an MTS 810. The data were submitted to two-way ANOVA and Tukey's test (p = 0.05). Wet dentin presented the highest TBS values for SB and CSEB. Dry dentin and re-wet produced significantly lower TBS values when using SB. OUBF was not affected by the different conditions of the dentin substrate, producing similar TBS values regardless of the surface pretreatments. Descriptors: Dentin permeability; Dentin-bonding agents; Tensile strength.Resumo: O uso de condicionadores ácidos para desmineralizar a superfície dental e expor a rede de fibras colágenas para interdifusão dos monômeros adesivos e conseqüente formação da camada híbrida tem sido considerado o mais eficiente mecanismo de adesão dos agentes de união. O objetivo deste estudo foi comparar a resistência de união à dentina de três sistemas adesivos, dois autocondicionantes (Clearfil SE Bond -CSEB e One Up Bond F -OUBF) e um de condicionamento total (Single Bond -SB), sob três diferentes condições de substrato dentinário (úmido, seco e reidratado). Noventa terceiros molares humanos recém-extraídos foram cortados na superfície oclusal, para se remover o esmalte e formar uma parede plana de dentina. Os espécimes foram restaurados com resina composta (Filtek Z250) e submetidos ao teste de resistência de união à tração (TBS) em uma MTS 810. As médias foram submetidas à ANOVA a dois critérios e ao teste de Tukey (p = 0,05). A dentina úmida apresentou os maiores valores de TBS para os sistemas adesivos SB e CSEB. A dentina seca e a reidratada apresentaram TBS significativamente menor quando foi empregado SB. OUBF não apresentou resultados influenciados pela condição do substrato dentinário, tendo produzido TBS similares para os diferentes tratamentos de superfície. Descritores: Permeabilidade da dentina; Adesivos dentinários; Resistência à tração.

Does 2% chlorhexidine digluconate cavity disinfectant or sodium fluoride/hydroxyethyl methacrylate affect adhesion of universal adhesive to dentin?

“…Results of laboratory studies found in the literature is controversial regarding whether or not to use this agent and there is not much information on how these agents may affect the bond of composite resin materials. In previous studies, the morphology of the adhesive interface has been studied to in order to identify the hybridization patterns provided by adhesive systems under many different conditions [20,21]. The collapse in collagen fibers, caused by dentin hydration [22], limits the possibility of the micromechanical retention of the adhesive system in primed dentin.…”

One-Year Evaluation of a Simplified Ethanol-Wet Bonding Technique: A Randomized Clinical Trial

“…Theoretically, there is no or small difference between the depths of demineralization and resin infiltration induced by this system because both processes occur simultaneously (14)(15)(16). However, this adhesive strategy also has high hydrophilicity, which attracts water and compromises adhesive interface integrity (17,18).…”

Bond Strength of Newer Dentin Bonding Agents in Different Clinical Situations

“…1 Dental adhesive systems are used to promote adhesion between composite resins and dental structure and should present a similar performance on both enamel and dentin. 2 Resin bonding to enamel is considered a durable and predictable clinical procedure. [3][4][5] The micromechanical nature of the interaction of dental adhesives with enamel is a result of the infiltration of resin monomers into the microporosities left by acid dissolution of enamel and the subsequent enveloping of the exposed hydroxyapatite crystals with polymerized monomers within pores in the enamel surface.…”

“…5 The dentin substrate differs from enamel, as it presents more organic contents, an increased presence of fluid inside the dentinal tubules, a smear layer, and an inherent surface wetness. 2,7 Adhesive systems can be classified based on how they react with the smear layer. Three mechanisms of adhesion are currently in use with modern adhesives: etch-and-rinse adhesives, which remove the smear layer and superficial hydroxyapatite through etching with a separate acid gel; self-etch adhesives, which make the smear layer permeable without removing it completely; and glass ionomer adhesives, which are self-adhesive to tooth tissues.…”

“…8 The total-etch and self-etch adhesive systems are contemporary and are both dividing the preference of clinicians, mainly when technical simplification vs effectiveness of adhesion to different dentinal substrates is considered. 2 Dental adhesives display different bonding strengths on different substrates and in different conditions on the same substrate. 10 The durability of the adhesive-dentin interface is related to its quality, based upon the ability of adhesive monomers to occupy the spaces created by the removal of apatite mineral by acid etching and on their ability to envelop the exposed collagen fibrils.…”