Effect of Endodontic Irrigation on Adhesion to Pulp Chamber Dentin

Objective: This study aimed to evaluate in vitro the effect of endodontic irrigants on the bond strength of a self etching adhesive to bovine pulp chamber dentin. Methods: 70 crowns of bovine mandibular incisors were cut to expose the pulp chamber. The pulp was extirpated and the root canal orifice sealed with temporary restorative material. The specimens were divided into seven experimental groups, according to the solution used: G1- 0,9% NaCl (control group), G2- 5,25% NaOCl, G3- 5,25% NaOCl and 17% EDTA, G4- 2% chlorhexidine gluconate solution, G5- 2% chlorhexidine gluconate solution and 17% EDTA, G6- 2% chlorhexidine gluconate in a gel base, G7- 2% chlorhexidine gluconate in a gel base and 17% EDTA. Each solution remained 30 minutes in contact with pulp chamber dentin, except for EDTA, which was left for 5 min. After irrigation, teeth were washed and blot-dried. A self etching adhesive system, Clearfil SE Bond, was applied according to manufacturer's instructions, followed by Filtek Z250 composite. After 24h storage in 37°C distilled water, the microtensile bond test was performed. Results: A log-rank test was applied to analyze the bond strength values, expressed in MPa [mean±SD]: G1: 37,25 ± 2,07^a; G2: 26,40 ± 2,07^c; G3: 20,37 ± 1,46^c; G4: 35,75 ± 1,85^ab; G5: 34,79 ± 2,16^ab; G6: 36,20 ± 1,53^ab; G7: 33,09 ± 1,53^b. NaOCl groups (G2 and G3) presented the lowest mean bond strength, which differed statistically from the others groups. Chlorhexidine gel + EDTA group (G7) also showed bond strength values statistically different from the control group. Conclusion: Based on the conditions of this experiment, bond strength of Clearfil SE Bond to bovine pulp chamber dentin was negatively affected by endodontic irrigation with 5,25% NaOCl associated or not to 17% EDTA. Supported by: CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior).