Iranian Dental Association Journal of Iranian Dental Association 3060-8201 17 2 2005 05 01 An evaluation on the effects of 37% phosphoric acid and self – etching primer on shear bond strength of enamel 68 75 EN Abdolrahim Davari Hila Hajizadeh Hasan Sharifikhatoonabadi Journal Article 2007 05 12 2013 02 25 An evaluation on the effects of 37% phosphoric acid and self – etching primer on shear bond strength of enamel Dr. A. Davari* - Dr. H. Hajizadeh* - Dr. H. Sharifikhatoonabadi** *- Assistant Professor of Operative Dentistry Dept. - Faculty of Dentistry - Yazd University of Medical Sciences. **- Dentist. Background and Aim: The goal of this study was to evaluate the effects of 37% phosphoric acid and self – etching primer on the bond strength of composite resin to enamel. Materials and Methods: Twenty bovine mandibular incisors were mounted in self – curing acrylic resin, and facial enamel surfaces were ground wet on 600 – grit disc paper. Then specimens were divided into three groups of ten. Different enamel surface treatments were applied as follows: Group A: Etching with 37% phosphoric acid and enamel bonding agent (Colten). Group B: Self – etching bonding agent (Prompt – LP). Group C: Etching with 37% phosphoric acid and self – etching bonding agent (Prompt – LP). After adhesive curing, a column of composite of 2 mm diameter was cured on the surface. After one – week storage and thermocycling, specimens were debonded at a cross – head speed of 1mm/min using an Instron machine. The teeth were examined stereomicroscopically to assess the site of debonding. The data were subjected to one – way ANOVA and LSD test at 0.05 level of significance. Results: The mean shear bond strength values were 15.4±6.5, 24.8±9.7 and 25.4±11 MPa for groups A, B and C, respectively. The enamel – resin interface was the most common site for bond failure in group A. Cohesive failure, in composite or enamel was more common in groups B and C, respectively. The differences between groups B and C with A was significant but no statistically significant difference was found between groups B and C. Conclusion: Self – etching agents can be used as alternatives for conventional phosphoric acid enamel treatment. Key words: Enamel bonding – Self etch – Shear strength