The effectiveness of different irrigation strategies with laser activation on the bond strength of MTA as root end filling material: in vitro study

Abstract

Objective: To compare the push out bond strength of MTA apical plug in a simulated immature root, after using different irrigation protocols; NaOCl + 20% Etidronic acid (HEBP) and NaOCl + 17% Ethylenediaminetetraacetic acid (EDTA) with and without diode laser activation. Methods: Twenty-eight extracted single straight rooted permanent human teeth were selected. The root lengths were standardized (15 mm) by decronation of all samples. Instrumentation was done using the ProTaper Next system (Dentsply Sirona), the canals were flushed with 1 mL NaOCL after each instrument. Then, the apical 3 mm was cut perpendicular to the root’s long axis and the canals were prepared till file 90( master file) using the balanced force technique to simulate immature teeth. Samples were divided into four experimental groups (n = 7) in accordance with the irrigation protocol; G1 (NaOCl + HEBP), G2 (NaOCl + EDTA) both G1 and G2 were activated with diode laser, while G3 (NaOCl + HEBP) and G4 (NaOCl + EDTA) were activated with manual agitation. Canals were filled with a 5-mm MTA (ProRoot MTA, Dentsply Tulsa Dental) apical plug. Each root was transversely sectioned perpendicular to their long axis to have a 3 mm ± 0.1sections in thickness from the root apical portion. A push-out test was performed, and the failure pattern was assessed. Push out bond strength values were analyzed with student t test for compared pairs. Two-way ANOVA was used to detect the effect of each variable (chelating agent with/without laser activation). Result: Effect of diode laser activation in G1 and G2 showed no significant differences (p > 0.05) on the push out bond strength values of MTA, while in manual activated groups (G3 and G4), there was a statistically significant difference (p < 0.05) where G4 recorded higher push out bond strength mean values than G3. Conclusions: The diode laser activation when used with NaOCL and HEBP increased the effect of HEBP as chelating agent and improved the push out strength values of MTA, rendering it an alternative mild chelating agent in comparison with the EDTA.