Comparison shear bond strenght of bulk composite and posterior composites with different surface treatments

Aim; Acid and laser etching is applied on the dentin surface to increase the bond strength. In this study, the effects of both the layering methods and the etching methods on dentin bonding strength of composites were investigated. Materials and Methods; In our study, 180 noncarious and unrestored third molar teeth were used. All of the teeth were embeded to the auto polimerisan acryl in the rectangular plastic mold which were at the 3cm and 6cm edges and 4cm long as occlusal surface facing paralel with ground. The samples were randomly divided into three main groups (n = 60). Group 1 acid etching Group 2 Laser (Er: YAG) etching, and Group 3 control group. After that each group divided 4 sub groups. Four different restorative fillings materials were used on dentin surfaces of the samples in the subgroubs. The restorative filling materials were polymerized on the dentin surface by placing them in silicone transparent molds 3 mm in diameter and 4 mm in height. 3M P60, 3M Bulk fill,Tetric N Ceram and Tetric N Ceram Bulk fill restorative materials were used. Self-etch Universal Single Bond was used. In the Instron Universal test machine power applied as 1mm/minute speed till restoration broken from sample. Data recorded as a MPa. Fracture tips established on the broken samples surface with stereo microscope 40X magnification. Results; It was found that in 3M posterior and bulk fill groups while acid etching had higher shear bond strength compared to laser-etching statistically, laser-etching had higher shear bond strength compared to non-etching statistically (p<0,05). No statistically significant differance was found between laser etching,acid etching and control groups in Tetric N Ceram and Tetric N Ceram bulk fill applied samples. In this study, the difference between Tetric N Ceram and Tetric N Ceram bulk fill in the laser treated groups was found to be statistically significant (p<0,05). Conclusion; Laser etching may be used as an alternative to acid etching. Bulk fill method may be used in clinics in terms of bonding strength as an alternative to layering method. Keywords; Er:YAG, bond strength, bulk fill