Comparison of Dentin Bond Strength Between a Bioactive Resin-Modified Glass Ionomer Cement and a Conventional Self-Adhesive Resin Cement: An In Vitro Study

BACKGROUND AND AIM: Bond strength is one of the most important requirements for luting cements. Recently, bioactivity has been added to some cements to improve bond strength and mechanical and biological properties. This study aimed to compare the dentin shear bond strength between a bioactive resin-modified glass ionomer cement and a conventional self-adhesive resin cement. The null hypothesis was that there was no significant difference in dentin shear bond strength between the bioactive resin-modified glass ionomer cement and the conventional self-adhesive resin cement. MATERIALS AND METHODS: A total of 24 freshly extracted and collected mandibular premolars were embedded in acrylic bases, and the occlusal surface was shortened by 2 mm to expose the dentin. The specimens were divided equally into the following two groups: group A, the bioactive resin-modified glass ionomer cement (RMGIC) group (ACTIVA; Watertown, MA: Pulpdent), and group B, the conventional self-adhesive resin cement (Breeze; Wallingford, CT: Pentron). A total of 24 discs of the two cements were bonded to the occlusal dentin surface. The specimens were immersed in artificial saliva for 30 days and then subjected to 1000 thermal cycles at temperatures of 5°-55°C. The shear bond strength (SBS) test was then performed. The independent-samples t-test was used. RESULTS: The mean shear bond strength (SBS) of ACTIVA cement (group A) was 7.65±1.11 MPa, which was significantly higher than the mean of the Breeze group (group B) at 5.23±0.82 MPa (t=6.065, p<0.001), showing a mean difference of 2.42 MPa. Data in both groups were normally distributed, as indicated by the Shapiro-Wilk test (p>0.05). Consequently, the null hypothesis of no significant difference in dentin shear bond strength between the two materials was rejected. CONCLUSIONS: The dentin bond strength of bioactive resin-modified glass ionomer cement (RMGIC) was significantly higher than that of conventional self-adhesive resin cement. This finding underscores the effectiveness of bioactive glass components in stimulating hydroxyapatite formation, thereby strengthening chemical adhesion to dentin. Bioactive RMGIC is therefore recommended for luting restorations on vital abutments with compromised mechanical retention or large areas of exposed dentin, such as short or over-tapered preparations.