Effect of some temporary cements on the shear bond strength of dual-cured composite resin to enamel and dentin surfaces

The purpose of this in vitro study was to evaluate the shear bond strength of dual-cured composite cement after pretreatment of the enamel and dentin surfaces with eugenol-containing and eugenol-free temporary materials and comparing the results obtained with the control group [not pretreated with any temporary materials]. Cylindrical posts of dual-cured composite were bonded to the teeth surface by using syntac adhesive bond and positioned vertically to the flat dentinal area. The shear bond strengths were measured at composite-tooth surface interface by using a universal testing machine. The results of this study have shown that the shear bond strengths of dual-cured composite in the pretreated groups were highly significant in comparison with the control group at a significant level. It was concluded that the shear bond strength of dual-cured composite is effective on using temporary materials, particularly the eugenol-containing one. Also, syntac adhesive bond improved the bond strength of dual-cured composite/tooth interface

effect of dentin bonding agents on cervical microleakage of two types of composite resin restorations

This in vitro study was performed to evaluate the margin quality of two types of composite resin [Tetric Ceram and Kulzer]. Class II cavity preparations were restored using multi-incremental placement on the proximal surfaces of 60 extracted human molar teeth. In the first group [30 teeth], the cervical margin of class II cavity preparation lied apical to the cemento enamel junction. While, in the other group [30 teeth], the cervical margin lied above the cemento enamel junction. The restored teeth were immersed in methylene blue dye, the restorations were removed and the cavities were examined with stereomicroscopy for the detection of dye penetration. The results have shown that the teeth restored with Tetric Ceram type showed less microleakage than Kulzer type. For both types, the cervical microleakage at the composite resin/cementum interface was significantly greater than at the composite/enamel interface at a significant level