Shear bond strength of the metal bracket on the porcelain surface using three silane coupling agents: A laboratory-based experimental study

This study aims to assess differences in shear bond strength using three materials of silane coupling agents with various organosilane compositions. The samples were 21 porcelain plates categorized into three groups as follows: (a) Monobond Plus (agent A); (b) Ultradent Silane (agent B); and (c) Porcelain Repair Primer (agent B). 37% phosphoric acid etching, silane coupling agents and Transbond XT adhesive were applied to the porcelain surface, followed by 24-h immersion in distilled water before measuring shear bond strength. The results revealed statistically significant differences in shear bond strength among the three silane coupling agents. Agent A had the highest shear bond strength (12.827 ± 1.228 MPa) and B had the lowest shear bond strength (6.295 ± 0.642 MPa) and 6-8 MPa fulfilled the minimum criteria of shear bond strength. Per the Adhesive Remnant Index scores, agent B revealed a clean porcelain surface, whereas agent A and C displayed the presence of bonding adhesive on the entire surface of the porcelain. While agent A and C could be used if the porcelain is replaced, agent B could be used if porcelain is not replaced.