Microshear bond strength of resin composite to Ti6A14V titanium alloy after different chemical and mechanical surface treatments

This study aimed to compare the effects of different surface treatments including sandblasting, 9% hydrofluoric (HF) acid, 48% sulfuric acid (SA), and silica gel plus SA on micro-shear bond strength (μSBS) of resin composite to Ti6A14V titanium alloy. In this in vitro study, 60 Ti6A14V titanium alloy plates were randomly assigned to five experimental groups (n = 12) as follows: Group (1) untreated, Group (2) sandblasted (50 μm aluminum oxide particle), Group (3) acid etched in 9% HF for 60 s, Group (4) acid etched in 48% H2SO4 at 60 °C for 30 min, and Group (5) acid etched in 50% silica-sulfuric acid (SiO2-H2SO4) at 60 °C for 30 min. Profilometric examination and scanning electron microscopy (SEM) were performed. A universal adhesive resin was applied to the plates and light-cured. One tygon tubes was placed perpendicularly to each plate. The resin composite was then placed on the treated plates and light-cured for 40 s. μ-SBS and failure mode were analyzed after 2000 thermal cycles (5 to 55 °C). Data were analyzed by ANOVA, Tukey, and Chi-square tests at the significance level of 0.05. The μSBS was significantly different among the groups (P = 0.032). The mean µSBS of the control group was significantly lower than that of sandblasting (P < 0.001), SA etching (P = 0.009) and silica-SA (P = 0.003) groups. The Ra of sandblasting (P = 0.021) and silica-SA (P = 0.004) groups was significantly higher than the control group. Also, the Ra of HF acid group was significantly lower than that of sandblasting (P = 0.035) and silica-SA (P = 0.007) groups. The Rz of sandblasting group was significantly higher than all other groups (P < 0.001 for all). Within the study limitations, surface treatment by sandblasting resulted in the highest surface roughness and μSBS of Ti6A14V alloy-resin composite followed by silica gel-SA, SA etching, and HF.