Effect of surface conditioning on the shear bond strength of compomers to human primary and permanent enamel.

PURPOSE

To compare the bond strength of two polyacid-modified composite resins (Compomer) to primary and permanent enamel with and without acid-etching and to test for a possible relationship between the determined shear strength values and area of cohesive failure within the materials on the bonding interface.

MATERIALS AND METHODS

Two compomer materials (Dyract and Compoglass) with their respective one-bottle primer/adhesive agents (Prime & Bond 2.0 and Syntac Single Component) were investigated. The parameters tested were shear strength and area of cohesive type of failure after debonding of specimens with respect to the total area of the bonding interface.

RESULTS

Mean bond strength to primary enamel ranged from 4.09 MPa (Compoglass) to 5.6 MPa (Dyract), while in permanent enamel the mean values were between 12.3 MPa (Compoglass) and 14.3 MPa (Dyract), when pretreatment was made with bonding agents only. Generally, acid-etching prior to pretreatment improved adhesion significantly (6.0 MPa and 8.1 MPa in primary enamel and 16.0 MPa and 19.4 MPa in permanent enamel for Compoglass and Dyract, respectively). Over one-half of the variation in the values for cohesive failure area was explained by its linear relationship with shear bond strength.