Abstract

SANTOS, Lorena Rodrigues et al. The hydrofluoric acid in the shear strength between feldspathic ceramic and composite resin. Rev. Assoc. Paul. Cir. Dent. [online]. 2015, vol.69, n.1, pp. 62-67. ISSN 0004-5276.

Among the restorative materials the porcelain is distinguished by its high potential in reproducing the dental aspect. In this way, their use has been growing increasingly, and, with it the possibility of fracture. However, not every failure demands the exchange the restoration because the possibility of a repair exists with compounded resin. This study evaluated the shear bond strength between composite resin and feldspathic ceramic subjected to etching surface with hydrofluoric acid (HF) at different concentrations. Thirty-six porcelain specimens were mounted into acrylic resin, polished and divided into 3 groups (n=12), according to the following surface treatments: G1) without treatment (control); G2) etched with 10% HF for 120 seconds; G3) etched with 5% HF for 120 seconds. Then the treatment, silane coupling agent and adhesive were applied to the treated specimens, after being bonded with of composite resin with the aid of a bipartite metal matrix. After a 7 days of storage at 37° C, the specimens were subjected to a shearing force in a universal testing machine at a crosshead speed of 0.5 mm/min. The average shear strength were: G1 105.3 N; G2 182.5 N and G3 154.51 N. In the analysis of quantitative data (T student) was difference statistically significant between all groups (p <0.05). Optical microscopy revealed approximately 58% of cohesive failures in the control group, 75% to G3 and 83% for G2. It was concluded that adherence with HF was 10% greater adhesion with the 5% HF.

Keywords : hydrofluoric acid; shear strength; dental porcelain..