BACKGROUND With the changing demand in dentistry, a wide range of dental materials is present in the market today. Choosing the best material for a given situation becomes confusing for a clinician. Shear bond strength gives an idea of retentiveness of a material partially. The purpose of the study was to determine and compare shear bond strength (SBS) of packable glass ionomer cement (GIC), resin- modified glass ionomer cement (RMGIC), compomer, and giomer to primary and permanent teeth. METHODS An in-vitro, experimental study was done. 60 freshly extracted permanent first premolars, extracted for orthodontic purpose and 60 freshly extracted over-retained deciduous molars were collected and kept in two groups. Specimens in each group were randomly divided into six subgroups depending on the material to be used. Flat dentinal surface on tooth was prepared over which restorative materials were placed. The prepared specimen was subjected to shear test and the value obtained was compared. Descriptive statistical analysis was performed to calculate the mean shear bond strength of each group. Also, analysis of variance (ANOVA) followed by Tukey’s test was performed with the help of critical difference (CD) at 5 % and 1 % level of significance. The debonded specimen were examined to assess the mode of failure. RESULTS Intragroup comparison for primary teeth showed that composite resin had the highest shear bond strength value (16.21 ± 1.12), followed by Giomer (14.25 ± 1.13), compomer (10.27 ± 1.38), RMGIC (6.06 ± 1.04), packable GIC (3.01 ± 0.85) and conventional GIC (2.94 ± 0.91). In permanent teeth, similar order was seen with composite resin showing highest bond strength (17.82 ± 1.50) followed by Giomer (15.26 ± 1.54), compomer (12.54 ± 1.36), RMGIC (7.00 ± 0.89), packable GIC (3.35 ± 0.98) and conventional GIC (3.30 ± 1.03). Intergroup comparison revealed, the values of shear bond strength (SBS) of all the materials tested was lower in primary teeth. However, the difference was statistically insignificant for conventional GIC and packable GIC. The mode of failure for packable GIC specimens was cohesive within the material, which suggests that the values obtained may not be the strength of the bonded interface but the strength of the material. In RMGIC it was predominantly mixed (cohesive within the material), which indicates that the values obtained were not clearly the strength of the bonded interface but due to inherent weakness of the material. The mode of failure in compomer and Giomer was adhesive failure suggesting that the value obtained was of adhesive bond formed at the interface. CONCLUSIONS Giomer and compomer proved to be the materials with high adhesiveness, so these can be recommended as a suitable restorative material for both primary and permanent teeth. Of the four materials tested, Giomer was found to be the best in terms of SBS in both the primary and permanent teeth. KEY WORDS Compomer, Glomer, Packable GIC, RMGIC, Shear Bond Strength
