Effect of hydrofluoric acid treatment on shear bond strength and surface characterstics of titanium alloys: an in-vitro study

Purpose: The purpose of this in-vitro study was to evaluate the effect of Hydrofluoric acid treatment on shear bond strength and surface characteristics of Titanium alloys. Methods: 3 dental luting agents representative of different compositional classes (Polycarboxylate, Glass ionomer, and Zinc oxide based cements) were used to evaluate their effect on Titanium-6Aluminum-4 Vanadium (Ti-6Al-4V) alloy surfaces. Samples were divided according to their surface etching with 9.6% Hydrofluoric acid (n=15 for each group). Group (1) Titanium alloy cylinders with acid etching. Group (2) Titanium alloy cylinders without acid etching. 30 pairs of cylinders were cemented together. Shear Bond strength was measured using a Universal testing machine at a crosshead speed of 5mm/min after incubation in a water bath at 37°C for 7 days. SEM was used to observe the representative specimens for the surface characteristics under 500X magnification. Results: Polycarboxylate cement showed significantly greater retention than all other groups (P<0.05).SEM examination showed surface pits on the Hydrofluoric acid etched Titanium alloy cemented with Polycarboxylate cement. Conclusion: Higher Shear bond strength and some chemical surface changes were observed in acid etched Ti alloy group cemented with Polycarboxylate cement.