Effect of caries-affected dentin on one-step universal and multi-step etch-and-rinse adhesives’ bond strength

Abstract

ResumoObjetivo: Avaliar a influência da dentina afetada na resistência de união de um sistema adesivo universal e de um adesivo de condicionamento ácido total acetonado. Material e método: As faces oclusais de 60 terceiros molares humanos, hígidos e cariados, foram removidas a fim de expor o substrato dentinário. Os dentes foram divididos aleatoriamente em 6 grupos: Single Bond Universal (3M Dental Products, Seefeld, Germany), nos protocolos de condicionamento total e autocondicionante, e Prime&BondNT (DentsplyDeTrey, Konstanz, Germany), em dentina hígida e afetada. A smearlayer de 30 espécimes de dentina hígida foi padronizada com lixas de granulação 600. A dentina residual infectada de 30 espécimes foi removida com uma broca carbide número 4 até que nada fosse detectável por uma inspeção clínica. Pinos de resina composta (Filtek Z350 XT, 3M ESPE, St. Paul, MN) foram construídos usando tubos de amido como matriz. O teste de microcisalhamento foi realizado em uma máquina universal de testes até que houvesse a fratura. Resultado: Diferenças significantes foram observadas na resistência de união apenas para os espécimes de dentina afetada. A resistência de união do Single Bond Universal não foi influenciada pelo protocolo de aplicação nos espécimes de dentina hígida, mas diminuiu para os espécimes de dentina afetada, enquanto que o desempenho da adesão do Prime&BondNT não foi influenciada pela condição dentinária. Conclusão: A dentina afetada reduziu a resistência de união do Single Bond Universal, em comparação à dentina hígida. A resistência de união do Prime & Bond NT não foi alterada pela condição dos substratos.Descritores: Dentina afetada por cárie; substrato dentinário; sistema adesivo multimodo. AbstractObjective: To evaluate the influence of caries-affected dentin on bond strength of a universal one-step and a multi-step etch-and-rinse adhesive system. Material and method: Enamel of 60 third human molars with and without caries was removed to expose dentin. The teeth were randomly assigned to six groups: Single Bond Universal (3M ESPE, St. Paul, MN, USA) in etch-and-rinse and in self-etch mode and Prime & Bond NT (Dentsply Co, Konstanz, Germany), all on sound and caries-affected dentin. Smear layer of the 30 sound dentin specimens was standardized by polishing with 600-grit SiC paper under water cooling. Residual infected dentin of the 30 caries-affected specimens was removed with a number 4 CA carbide bur until no caries smooth tissue was detectable by tactile-visual inspection. Cylinders of a light cured composite resin (Filtek Z350 XT, 3M ESPE) were built up using starch tubes and microshear test was performed until failure. The data was analyzed by one-way ANOVA and Tukey's post hoc test. Result: Significant differences in microshear bond strength (μSBS) were observed for the caries-affected groups, but not for sound dentin. The μSBS of Single Bond Universal were not influenced by the application protocol on sound dentin, however they were lower in the caries-affected group with both application proto...

Bond Strength and Micromorphological Features of Dentin Substrates Treated With Different Etching Modes Using Universal Adhesive System

“…On the other hand, this research disclosed that the use of self-etch mode on sound dentin (28.04±1.30 MPa) had statistically significantly higher bond strength than that of total-etch mode (24.02±1.03 MPa). These results were in agreement with that of Müller et al who found superior bonding results using single-bond universal on sound dentin to Prime and Bond NT [7] . This may be attributed to the fact that one coat 7 univeral adhesive, used in this study, is versatile and can be used as both etch and rinse mode or as self-etch mode; and that the only difference between the two modes was the use of 37% phosphoric acid in case of the self-etch mode; while the application of the phosphoric acid as a separate step did not improve bond strength results on sound dentin.…”

“…Regarding teeth selection, in this study, human carious molars were selected with carious lesion on the occlusal surface rather than proximal surface that had more liability for being exposed, and so caries affected dentin was accurately obtained from molars occlusal surface surrounded by sound dentin [7,11] . Also the types of decay present in molars were chronic caries rather than acute caries, since the incidence of pulp exposure is more likely to occur in acute caries.…”

“…Based on science of cariology and as stated by Fusyama, dental caries has two distinctive layers, the outer layer consists of caries infected dentin which is highly demineralized and full of bacteria, and should be removed clinically during caries treatment by excavation, and the inner layer which is the caries affected dentin that is partially demineralized and is bacterial free and can be maintained during caries excavation as it can be remineralized [5,6] . Studies revealed that bonding to caries affected dentin has lower bond strength than that of normal sound dentin due to its weaker structure that limits resin imoregnation as dentinal tubules is filled with acid resistant mineral deposits beside the formation of thicker hybrid layer [3,7] .…”

“…The most effective approach to obtain adequate bond strength to dentin was accomplished by the infiltration of the resin monomers inside the demineralized collagen fibril to form the hybrid layer and the creation of resin tags that sealed opened dentinal tubules. The efficacy of these simplified adhesive techniques was still questionable and most of the researches published used sound dentin as bonding substrate while nowadays the old concept of extension for prevention had been replaced by minimal intervention dentistry which advocate minimal removal of hard tooth structure [4] , excavation and removal of outer layer that consists of highly infected carious dentin and preserving inner layer of bacteria-free remineralizable caries affected dentin and so clinically most of bonding procedures occurred on caries affected dentin [7,8,9] . Previous studies found a decrease in the bond strength of self-adhesive systems to the caries affected dentin, however, that of the newly simplified universal adhesives are less reported and studied [4] .…”

Análise de diferentes sistemas adesivos em estudos in vitro: uma revisão

“…O Prime & Bond NT®, é um adesivo de condicionamento total de 2 passos, Muller et al 21 observaram que a força de adesão deste é menor quando comparada com o Single Bond Universal®, porém não é alterada pelo substrato diferentemente do segundo. Quanto a utilização da clorexidina 2% após a etapa de ataque ácido, Grande 15 observou interferência na resistência de união e não na degradação ao longo do tempo.…”