Enamel etching by carbon dioxide laser. An in-vitro comparative evaluation.

The enamel surfaces etched with carbon dioxide laser and 37% phosphoric acid were compared with regard to surface topography. The shear bond strengths of composite bonded to enamel etched by laser and acid were also compared in the study. Out of the 72 human healthy premolars selected for the study, 12 teeth were used for studying the surface topography using scanning electron microscope. The shear bond strengths were evaluated using a Hounsfield Tensometer in the remaining 60 teeth. Under scanning electron microscope, carbon dioxide laser etching of enamel produced a poor etch pattern. The shear bond strengths of composite bonded to laser etched enamel appeared inferior as compared to those on acid etched enamel. Paired t-test gave a statistically significant difference between the shear bond strengths of composite bonded to laser etched and acid etched enamel surfaces.