Effect of H3PO4 concentration on bond strength
Abstract
Prior to bonding, the enamel surface of the tooth is normally etched using a solution of 37%–50% phosphoric acid (H3PO4) for 60 seconds. The purpose of this study was to evaluate the tensile bond strength, debonding interface distribution and enamel surface detachment of various concentrations of H3PO4 solution, from 2% to 8O%, applied for 15 seconds. Statistically significant differences in bond strength were found among the various concentrations tested: concentrations in the 10% to 60% range produced greater bond strengths than both the weaker and stronger concentrations. The weaker the bond strength, the greater the debonding interface between resin and enamel. The greater the bond strength, the greater the debonding interface between the bracket and resin. Enamel detachment occurred as the H3PO4 concentration rose above 30%. To obtain greater bond strength and less enamel detachment, 10%–30% concentrations of phosphoric acid for 15 seconds etching are suggested for clinical bonding.
Contributor Notes
Wei Nan. Wang is Head of the Orthodontic and Pedodontic Section, Department of Dentistry, Tri-Service General Hospital and Associate Professor, School of Dentistry, National Defense Medical Center, Taipei, Taiwan
Ching Lin. Yeh is Chairman of the Department of Dentistry, Tri-Service General Hospital and Associate Professor, School of Dentistry, National Defense Medical Center
Ber Duen. Fang DDS is a resident in the Orthodontic and Pedodontic Section, Department of Dentistry, Tri-Service General Hospital and an assistant in the School of Dentistry, National Defense Medical Center
Kuo Ting. Sun is a resident in the Orthodontic and Pedodontic Section, Department of Dentistry, Tri-Service General Hospital and an assistant in the School of Dentistry, National Defense Medical Center
Michael G. Arvystas DMD is a Professor in the Orthodontic Section, University of Medicine and Dentistry of New Jersey, New Jersey Dental School, Newark, N.J. and an orthodontist at the Center for Craniofacial Disorders, Montefiore Medical Center, Bronx, N. Y. U.S.A