ABSTRACT

Tensile bond strengths of an orthodontic resin cement were compared for 15, 30, 45 or 60 second etching times with a 37% phosphoric acid solution on the enamel surfaces of young permanent teeth. Fourty extracted premolars from 9-to 16-year-old children were used for testing. An orthodontic composite resin was used to bond the brackets directly onto the buccal surface of the enamel. The tensile bond strengths were tested with an Instron machine. Bond failure interfaces of bracket bases were examined with a scanning electron microscope (SEM). The results of tensile bond strengths for 15, 30, 45 and 60 second etching times were not statistically significant. Of the bond failures 50% contained enamel fragments for 45sec. etching time. To achieve good retention, to decrease enamel loss and to reduce moisture contamination in the clinic, as well as to save chairside time, a 15 second etching time is suggested for teenage orthodontic patients.