Effect of Bleaching Method and Curing Time on the Surface Microhardness of Microhybrid Composite Resin.

The present study aimed to evaluate the effect of curing time and bleaching agents on microhybrid composite resin surface microhardness. A total of 180 microhybrid composite resin disks were divided into two groups in terms of curing time: 40 s, 60 s. Then, each group was divided into three subgroups: control (distilled water), home bleaching (15% carbamide peroxide) and office bleaching (40% hydrogen peroxide).

Er,Cr:YSGG Laser as a Novel Method for Rebonding Failed Ceramic Brackets.

Objective: Since there is no standard method for rebonding loose ceramic brackets, the aim of this study was to evaluate the possibility of using Er,Cr:YSGG laser to eliminate the remaining composite materials from the base of ceramic brackets and to compare the bond strength of rebonded brackets with the new ones.

Materials And Methods: Sixty-two extracted human premolars were mounted in acrylic cylinders. Thirty-one ceramic brackets were bonded, and shear bond strength was tested using Hounsfield testing machine.