OBJECTIVE: The aim of this in vitro study was to evaluate the bond strength of different root canal sealers to dentin. MATERIAL AND METHODS: Forty extracted single-rooted human teeth were examined and the coronal and middle thirds of the canals were prepared with a 1.50 mm post drill (FibreKor Post System, Pentron). The teeth were allocated in two experimental groups, irrigated with 2.5% NaOCl+17% EDTA or saline solution (control group) and instrumented using Race rotary files (FKG) to a size #40 at the working length. Then, the groups were divided into four subgroups and filled with Epiphany sealer (Group 1), EndoREZ (Group 2), AH26 (Group 3) and Grossman's Sealer (Group 4). After 2 weeks of storage in 100% humidity at 37ºC, all teeth were sectioned transversally into 2-mm-thick discs. Push-out tests were performed at a cross-head speed of 1 mm/min using a universal testing machine. The maximum load at failure was recorded and expressed in MPa. RESULTS: Means (±SD) in root canals irrigated with 2.5% NaOCl and 17% EDTA were: G1 (21.6±6.0), G2 (15.2±3.7), G3 (14.6±4.5) and G4 (11.7±4.1).Two-way ANOVA and Tukey's test showed the highest bond strength for the Epiphany's group (p< 0.01) when compared to the other tested sealers. Saline solution decreased the values of bond-strength (p<0.05) for all sealers. CONCLUSION: Epiphany sealer presented higher bond strength values to dentin in both irrigating protocols, and the use of 2.5% NaOCl and 17% EDTA increased the bond strength values for all sealers.

O objetivo desse estudo in vitro foi avaliar a resistência de união do cimento resinoso Epiphany™ às paredes dentinárias após aplicação de pastas de hidróxido de cálcio [Ca(OH)2]. Quinze dentes humanos uniradiculares foram igualmente instrumentados sob irrigação com as soluções de NaOCl 2,5% + EDTA. Os dentes foram divididos em três grupos (n=5) e tratados com diferentes pastas de Ca(OH)2: G1= Ca(OH)2 + soro fisiológico; G2= Ca(OH)2 + 2% CHX e G3= tratado apenas com soro fisiológico (grupo controle). Após 10 dias de armazenamento a 37°C e 100% de umidade, as medicações foram removidas e os dentes obturados com o cimento Epiphany. Passadas 48 horas de armazenamento adicional, as amostras foram seccionadas tranversalmente em discos de 2 mm de espessura. Os testes de resistência de união (push-out) foram realizados em máquina de ensaio mecânico (1 mm/min) e os resultados expressos em MPa. Os testes de ANOVA e Newman-Keuls mostraram um significante decréscimo nos valores de resistência de união quando as pastas de Ca(OH)2 foram utilizadas (10,18 ± 1,99 e 9,98 ± 2,97) em comparação ao grupo controle (13,82 ± 3,9) (p<0,05). Pode-se concluir que o uso do Ca(OH)2 como medicação intracanal diminuiu a adesão do cimento Epiphany™ às paredes dos canais radiculares, embora os valores de resistência de união estejam dentro das médias aceitáveis encontradas na literatura.

The aim of this in vitro study was to evaluate the bond strength of Epiphany™ resin-based sealer to dentin walls after placement of calcium hydroxide [Ca(OH)2] dressings. Fifteen extracted single-rooted human teeth were instrumented using 2.5% NaOCl + EDTA as irrigants. The teeth were randomly assigned to 3 groups (n=5), according to the intracanal dressing: G1= Ca(OH)2 + saline; G2= Ca(OH)2 + 2% chlorhexidine gluconate (CHX) gel; and G3= saline (control). After 10 days of storage in 100% humidity at 37ºC, the dressings were removed and the root canals were filled with Epiphany™ sealer. After additional 48 h of storage, the specimens were sectioned transversally into 2-mm-thick discs. Push-out tests were performed (1 mm/min, Instron 4411) and the maximum loads at failure were recorded in MPa. One-way ANOVA and Newman-Keuls tests showed a statistically significant decrease in bond strength when a Ca(OH)2 dressing was used before root canal filling with Epiphany™ (G1= 10.18 ± 1.99 and G2= 9.98 ± 2.97) compared to the control group (13.82 ± 3.9) (p< 0.05). It may be concluded that the use of Ca(OH)2 as an intracanal dressing material affected the adhesion of Epiphany™ to the root canal walls, but even though the values were within the acceptable range found in the literature.