Evaluation of Shear Bond Strength of Conventional and Resin-Modified Glass Ionomers on Enamel, Dentin and Cementum Surfaces

According to appropriate characteristics of glass ionomer cementum and constant increase of its usage in restorative field, so comparison of conventional and resin- modified glass ionomers seems to be useful. This study was designed to determine the shear bond strength of conventional and resin- modified glass Ionomers on enamel, dentin and cementum.

This was an experimental study. Totally 60 molar intact teeth were divided into six groups. In groups A and D the surface of enamel was prepared 1mm, in groups B and E, the preparation was continued until the surface of dentin was exposed and in groups F and C the surface of cementum was only refreshed. In groups A, B, and C conventional glass ionomer and in groups F, E, and D resin-modified glass ionomer was used. For each specimen a plastic cylinder with 2mm diameter and 3mm height was bonded on treated surface and the teeth were filled by the relevant glass ionomer. In groups F, E, and D glass ionomer was light cured for 40 seconds. specimens were loaded to failure in a universal testing machine Then statistical analysis was performed using one- way ANOVA and LSD test (P=0.05).

The mean shear bond strength of groups A, B, C, D, E and F were 17.25, 14.77, 15.37, 27.30, 57.80, 23.50 Mpa, respectively. The difference between shear bond strength of groups F, E, and D with groups A, B, and C was statistically significant (P=0/001).

The shear bond strength of the resin-modified glass Ionomers was significantly higher than that of conventional glass ionomer in all three surfaces.