Role of Laser Etching on Shear Bond Strength between Recast Nickel-Chromium Alloy and Dental Ceramic: An Experimental Study.

Objectives: The purpose of this study was to investigate the effect of laser etching, air bone particle abrasion and acid etching on shear bond strength between re-cast Nickel Chromium alloy and dental ceramics. Materials and Methods: A master die was made according to ISO 9693; TR (11406). A total of 40 samples were fabricated with 50%w nickel-chromium alloy and 50%w previously casted nickel-chromium alloy. The samples were divided into four groups based on the surface treatment applied. Group 1 served as the untreated control, Group 2 underwent etching with 10% hydrochloric acid (HCl), Group 3 received surface treatment via air-borne particle abrasion, while Group 4 was conditioned using a pulsed Nd:YAG laser. Shear bond strength between ceramic and metal was tested using a universal testing machine and the mode of debonding was evaluated using scanning electron microscope. The obtained values were statistically analyzed using one-way ANOVA and Tukey's HSD Post Hoc test. Results: The mean values of shear bond strength for Group 1 was 22.69±2.63Mpa, Group 2 was 27.05±2.15Mpa, Group 3 was 34.46±2.46Mpa and Group 4 was 39.54±2.16Mpa. The difference among the groups was significant (P<0.001). Hence there was a statistical difference seen in shear bond strength between control and acid etching, air borne particle abrasion and laser etching. Conclusion: Laser surface conditioning produced more surface roughness compared to acid etching and air bone particle abrasion on re-cast Nickel Chromium alloy which increased the shear bond strength markedly between recast nickel-chromium alloy and dental Ceramic.