Push-out bond strength of calcium-silicate cements following Er:YAG and diode laser irradiation of root dentin

This study aimed to compare the effects of diode and Er:YAG laser irradiation of root dentin on push-out bond strength of mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM) cements. An in vitro experimental study was conducted on 90 dentin discs, cut out of freshly extracted human teeth. The discs were instrumented to obtain 1.3-mm lumen diameter. Then, they were randomly divided into six groups (n=15). Groups 1 and 4 subjected to diode laser (Wiser, Doctor Smile, Italy) (980nm, 1W, continuous mode) for 10s and filled with MTA and CEM cements. Groups 2 and 5 subjected to Er:YAG laser (Deka, Italy) (2940nm, 1W, 10Hz, 230s) for 10s and filled with MTA and CEM cements. Groups 3 and 6 (control groups) were filled with MTA and CEM cements without laser irradiation. After 7days, push-out bond strength test was performed using a universal testing machine in order to evaluate the adhesion of the biomaterials to dentin. The samples were evaluated under a light microscope at x40 magnification to determine the mode of fracture. Data were analyzed using two-way ANOVA. The highest push-out bond strength (8.76 +/- 3.62MPa) was noted in group 1 (diode/MTA), which was significantly higher than the other groups (P<0.001). The lowest bond strength (2.61 +/- 0.81) was noted in group 6 (control/CEM). Diode laser significantly increased the bond strength of both cements (P<0.05), but Er:YAG laser irradiation only increased the bond strength of CEM and had no significant effect on MTA (P=0.603). The bond strength of MTA control group was higher than that of CEM control group (P=0.001). Push-out bond strength of endodontic cements can be affected by dentin conditioning with diode 980nm and Er:YAG laser. Nine hundred eighty-nanometer diode laser irradiation is recommended to increase the bond strength of endodontic cements particularly the CEM cement to dentin.