Influência de diferentes soluções irrigadoras endodônticas na resistência adesiva sobre a dentina superficial analisadas em microscopia eletrônica de varredura

Abstract

The use of irrigants and intracanal medications during the endodontic therapy may have an adverse effect on bonding to dentine structures. The aim of this study was to evaluate the influence of endodontic irrigants on tensile bond strength to superficial dentine with SEM observation afterwards. In this study 48 bovine incisors were used, they had their crowns embedded in epoxi resin. In order to obtain the dentin substrate used, the enamel was removed until we get an area of 3mm diameter of dentin. The experimental groups were divided according to the solution used: G1- 0,9% NaCl, G2- 2%chlorhexidine solution; G3- 2,5%NaOCl; G4- 1%NaOCl. Each group had 12 specimens. After the irrigants application and the restoration, the tensile test was accomplished on universal EMIC® machine, then one sample of each group were selected to SEM observation to analyze the fracture modes. The average results and standard deviation were G1=14,52 MPa (11,02); G2=17,96 MPa (7,64); G3=15,61 MPa (9,30); G4=19,24 MPa (5,92). Based on the results and the statistical analysis we can conclude that there were no significant differences among the tensile strength values after the dentin surface treatment. SEM analysis showed the presence mixed fractures modes with hybrid layer involved or more than a substrate (cohesive failure in resin, cohesive failure in dentin).