INTRODUCTION:Different techniques can be utilized in vitro to evaluate the durability of the bond strength to tooth structure. Shear bond strength test is one of these methods which have been widely used. Glass carbomer has been introduced with claims of improved physical characteristics in comparison with conventional GICs. OBJECTIVES: The aim of the study was to compare and evaluate the shear bond strength of glass carbomer to primary dentin versus a high viscosity glass ionomer (Fuji IX GP) MATERIAL AND METHODS: Twenty primary molar teeth extracted for orthodontic purposes or exfoliated by normal shedding were collected according to specific criteria from public hospitals in Alexandria and outpatient clinic of the Faculty of Dentistry, Alexandria University. Crown surfaces of the included teeth were mounted in acrylic blocks then, ground with water-cooled silicon carbide abrasive papers successively to obtain flat dentin surfaces. The prepared specimens (n=20) were divided into two groups according to the glass ionomer cement (GIC) bonded to the dentin surface (10/ each group): group I (Fuji IX GP) and group II (Glass Carbomer). Shear bond strength (SBS) between dentin surface and the bonded material was measured using a universal testing machine. RESULTS:The results revealed that, Fuji IXGP group recorded the highest mean SBS value (6.624) while, Glass Carbomer recorded mean value (2.870). There was a highly significant difference in shear bond strength values between both groups (p= 0.000). CONCLUSIONS:The high viscosity glass ionomer was higher in shear bond strength than glass carbomer glass ionomer and this finding may be salutary in GICs selection by dental practitioners.

Purpose: The purpose of this study was to evaluate the effect of three different base materials (GIC, Chemfill rock, and SDR,) on microleakage, fracture resistance, and color stability of two ceramic inlays (E max and Vita suprinity). Materials and methods: Sixty extracted premolars were prepared for Class II inlay MOD. For microleakage test thirty teeth divided into three groups (n=10); group (A): restored with (GIC). Group (B): restored with Chemfill rock. Group (C): restored with SDR. After thermocycling the microleakage was evaluated by scores. For evaluation of fracture resistance and color stability, the remaining thirty teeth were divided into two groups(n=15) Group (1): The teeth restored with Emax inlay. Group (2): restored with Vita Suprinity inlay. Each group was subdivided into three subgroups(n=5); Subgroup (I): based with (GIC). Subgroup (II): based with Chemfill Rock. Subgroup (III): based with SDR. Results: For microleakage test; SDR base had stage zero leakage, leakage was higher in GIC base. For fracture resistance test; there is statistically significant high mean of fracture resistance in SDR base. On the other hand there is no statistically significant difference as fracture resistance between E-max, and Vita Suprinity restoration. For color stability test; there is statistically significant difference high mean of color difference in SDR base with p-value <0.05. On the other hand there is no statistically significant difference between E-max, and Vita Suprinity restoration. Conclusion: SDR is the best base regarding microleakage, color stability and fracture resistance. While there is no significant difference between Emax and Vita Suprinity restorations. in color stability and fracture resistance.