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The aim of this study was to compare the effects of 2 aging methods on the dentin bond strength of different adhesive systems, including a universal adhesive. Seventy-two third molars were sectioned to create flat midcoronal dentin surfaces, which were randomly assigned to 12 groups (n = 6 each) according to the aging method (conventional aging, defined as 6 months of water storage; accelerated aging by means of a pH-cycling method; or negative control [immediate bond strength]) and adhesive system (Adper Single Bond 2, Clearfil SE Bond, Prime & Bond 2.1, or Scotchbond Universal). Composite resin blocks were constructed on the flattened dentin surfaces after application of the appropriate adhesive, and the specimens were stored in water for 24 hours. Specimens from the control group were immediately sectioned into resin-dentin sticks (0.8 mm2) and subjected to a microtensile bond strength test. Specimens from the experimental groups were sectioned and tested after undergoing the assigned aging method. Data were analyzed with 2-way analysis of variance and a Tukey test (α = 0.05). The study findings showed that neither aging method significantly affected the dentin bond strength (P = 0.917). Of the 4 adhesives, Adper Single Bond 2 had the highest bond strength value after aging (P < 0.001). Scotchbond Universal adhesive demonstrated statistically significantly higher bond strength values than Clearfil SE Bond and Prime & Bond 2.1, which had statistically similar values. Adhesive failures at the resin-dentin interface or adhesive failures mixed with cohesive failure of the adjacent substrate predominated in all groups. The 2 aging processes did not result in degradation of the adhesive interface or jeopardize the dentin bond strength of any of the adhesives tested.

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OBJECTIVE:  To evaluate the influence of endodontic irrigation protocols on bond strength of total-etch and self-etch adhesive systems to coronal enamel and dentin. MATERIALS AND METHODS:  A total of 66 coronal slices from 11 permanent molars were assigned to six groups (n = 11): endodontic irrigation protocols (5% sodium hypochlorite + 17% EDTA; 2% chlorhexidine gel + saline solution + 17% EDTA or no solution - control) and adhesive systems (Adper Single Bond 2 or Clearfil SE Bond). Dental slices were exposed to endodontic irrigation protocols for 30-minute prior to the application of the adhesive systems. Starch tubes were placed over the enamel and the dentin surfaces of each slice (2-4 tubes in each substrate) and filled with Filtek Z350 XT (3M ESPE) to build the microshear bond strength (µSBS) specimens (0.72 mm2 sectional area). After 24 hours of water storage (37°C), µSBS test was performed. Bond strength data (MPa) were analyzed by two-way ANOVA, separately for enamel and dentin (α = 0.05). RESULTS:  µSBS means were not influenced by endodontic irrigation protocols in enamel (p = 0.12) nor dentin (p = 0.49). Clearfil SE Bond system presented higher µSBS values than Adper Single Bond 2 both on enamel (p = 0.024) and dentin (p = 0.005). CONCLUSION:  Endodontic irrigation protocols (5% sodium hypochlorite or 2% chlorhexidine gel + saline solution combined with 17% EDTA) do not jeopardize the bond strength of adhesive systems to coronal enamel and dentin. CLINICAL SIGNIFICANCE: The results of this in vitro study suggest that endodontic irrigation protocols do not impair on bonding effectiveness of adhesive systems to coronal enamel and dentin. (J Esthet Restor Dent 29:222-228, 2017).

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Introduction: Increased adhesive temperature has been reported to promote solvent evaporation, reduce viscosity, and improve monomeric permeation into dentin. Objective: The aim of this study was to determine the influence of different heating methods on the microtensile bond strength of an etch-and-rinse adhesive to dentin. Material and method: Twenty-four caries-free extracted human third molars were transversally sectioned to expose a flat dentinal surface. The samples were etched with 37% phosphoric acid gel and divided into three groups (n = 8): 1) Control - the adhesive system (Adper Single Bond 2; 3M ESPE) was applied at room temperature; 2) Warming device - the adhesive was warmed to 37°C in a custom device before application; and 3) Warm air - the adhesive was warmed to 50°C with an air jet after application on dentin. The specimens were restored with a composite resin (Filtek Z250 A2, 3M ESPE) and prepared for microtensile bond strength testing, after 24 h in water storage. The data were subjected to one-way ANOVA and Tukey's test (p < 0.05). Result: There was no significant difference among the groups (p > 0.05). The mean bond strength values in the control, the warming device, and the warm air groups were 48.5 (± 5.2), 40.35 (± 4.9), and 47.2 (± 5.3) MPa, respectively (p = 0.05). Conclusion: The different heating methods had no significant influence on the immediate microtensile bond strength of an etch-and-rinse ethanol-based adhesive to dentin.

Introdução:O aumento da temperatura do adesivo tem sido pesquisado como forma de melhorar a evaporação do solvente, reduzir a viscosidade e melhorar a permeação dos monômeros na dentina. Objetivo: Investigar a influência de diferentes métodos de aquecimento na resistência de união à dentina sob um ensaio de microtração de um adesivo de condicionamento ácido total. Material e método: Vinte e quatro terceiros molares hígidos foram seccionados transversalmente a fim de expor a superfície plana da dentina. As amostras foram condicionadas ácido fosfórico a 37% e dividido em três grupos (n=8). São eles: 1) Controle - onde o adesivo (Adper Single Bond 2, 3M ESPE) foi aplicado em temperatura normal (25°C); 2) Dispositivo de aquecimento - O adesivo foi aquecido em um dispositivo específico até alcançar a temperatura de 37°C e só então aplicado à dentina; 3) Ar quente - Usou-se jato de ar aquecido a 50°C por 10 segundos a uma distância de 10cm para facilitar a evaporação do solvente. Os espécimes foram restaurados com resina composta (Filtek Z250 A2, 3M ESPE) e preparados para o ensaio de microtração, após 24h de armazenamento em água destilada. Os dados obtidos foram submetidos para análise de variância (ANOVA) e teste de Tukey (p< 0,05). Resultado: Não houve diferença significativa entre os grupos (p> 0,05). As médias da resistência de união para o grupo controle, dispositivo de aquecimento e ar quente foram, respectivamente, 48,5 (± 5,2), 40,35 (± 4,9), e 47,2 (± 5,3). Conclusão: Os diferentes métodos de aquecimento não influenciaram significativamente na resistência de união imediata à dentina de um Sistema adesivo de condicionamento ácido total.

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