بررسي اثر اسيدفسفريك 37 و پرايمرسلف اچ بر استحكام باند برشي به مينا

An evaluation on the effects of 37% phosphoric acid and self- etching primer on shear bond strength of enamel

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 (Cotten). 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.