A comparison of six enamel treatment procedures for sealant bonding

This in-vitro study evaluated the effectiveness of six different enamel treatment procedures for bonding a dental sealant. Sixty extracted human molar teeth were separated into the following enamel treatment groups (10 teeth each): group 1 (control)-etched with 37% phosphoric acid; group 2-air polished (air abraded) with 45 microns particles of sodium bicarbonate; group 3-air abraded with 50 microns aluminum oxide particles; group 4-etched with 2.5% nitric acid; group 5-air abraded with sodium bicarbonate particles and etched with 37% phosphoric acid; and group 6-air abraded with 50-microns aluminum oxide particles and etched with 37% phosphoric acid. The enamel treatment procedures were accomplished on intact mesial or distal surfaces. Following the enamel treatment, a sealant was bonded to the surfaces using a plastic matrix technique. After 24 hr of water storage at 37 degrees C, the specimens were debonded using an Instron machine. The mean shear bond strengths (MPa) were as follows: group 1-9.19 +/- 1.34 MPa; group 2-2.03 +/- 1.67 MPa; group 3-1.50 +/- 0.93 MPa; group 4-4.99 +/- 1.26 MPa; group 5-11.61 +/- 4.51; and group 6-11.14 +/- 1.70 MPa. Statistical analysis using a one-way ANOVA and Scheffe F-test revealed no significant difference (P > 0.05) among groups 1,5, and 6. However, there was a significant difference (P < 0.05) between groups 1,5, and 6 and the other three groups (2,3, and 4). In conclusion, 37% phosphoric acid treatment of intact enamel, or a combination of air abrasion with sodium bicarbonate or aluminum oxide followed by phosphoric acid, provides significantly higher bond strengths of a sealant material than enamel conditioning with 2.5% nitric acid or air abrasion with sodium bicarbonate or aluminum oxide.