Abstract
This study examined etching techniques by comparing tensile bond strengths with the concentration of phosphoric acid in etching agents to establish a technique that minimized adverse effects on human enamel. Enamel surfaces of human premolars were polished with an abrasive containing hydroxyapatite and then etched with the etchant for 30 s. Five wt% of aqueous phosphoric acid achieved sufficient for the enamel etching to afford the same bonding strength as 65 wt% acid. These data suggest that it is not necessary to use more concentrated phosphoric acid which could more severely demineralize the enamel surface.
