Evaluation of shear bond strength of feldspathic porcelain on various laser surface treated cobalt-chromium discs

Abstract

Brief Background The aim of the study is to compare and evaluate shear bond strength of porcelain fused to metal substructure fabricated using conventional method, surface treated with different laser modalities and direct metal laser sintering. Material and Methods Forty samples made of Co-Cr were fabricated, divided into control (Group A) and three test groups (Group B, Group C, Group D) (n=10 each). Groups A, C, D samples were made by conventional lost wax technique and B by laser sintering. All the samples were sandblasted and group C and D were surface treated with Nd: YAG and Er: YAG lasers respectively. Further, samples were veneered using 2mm of porcelain. The samples were placed in a jig and held in a universal testing machine to test the bond strength between Co-Cr and porcelain. Samples were subjected to shear stress until the fracture occurred and the results were noted. Data analysis was done using one- way analysis of variance and Post-Hoc test. Result The mean shear bond strength was highest in group D (Er: YAG laser treated Co-Cr), then group B (Laser sintered Co-Cr), then group A (Sandblasted Co-Cr) and group C (Nd: YAG laser treated Co-Cr) which was the least. Conclusion All the groups showed significant difference in shear bond strength. Er: YAG laser surface treated Co- Cr had highest bond strength to porcelain, then laser sintered Co-Cr, followed by sandblasted Co-Cr and least Nd: YAG surface treated Co- Cr. Key Words Er:YAG Laser, Nd:YAG Laser, Conventional technique, Co-Cr alloy, DMLS, Porcelain, Shear bond strength.