Comparative Evaluation of Microtensile Bond Strength of Three Restorative Materials

The present study aimed to compare the micro-tensile bond strength of new and conventional glass-ionomers and Z350 flowable composite resin to sound and caries-affected dentin. Eighty extracted third molars were selected. Standard Cl I cavities were prepared on occlusal surfaces. Forty teeth were assigned to the sound tooth group, and in the remaining 40 teeth, carious lesions were produced using a laboratory technique. Then each group (n=40) was subdivided into 5 groups (n=8) in terms of the restorative material used (EQUIA® Forte, Ketac Molar, encapsulated and hand-mixed GC Fuji II LC glass-ionomers and Z350 flowable composite resin). The cavities were restored. The highest micro-tensile bond strength was recorded with Z350 flowable composite resin in sound dentin (29.65), and the lowest was recorded with GC Fuji II LC (powder, liquid) in affected dentin (7.88). Significant differences were detected in the micro-tensile bond strength between the 5 restorative material groups. The composite resin bond strength was the maximum and was significantly different from all the other groups. The micro-tensile bond strength was affected by the type of dentin; in this context, in all the restorative groups, the bond strength in sound dentin was significantly higher than that in affected dentin. The most frequent failure mode was adhesive in the sound and affected dentin.