The ability of different irrigation methods to remove mixtures of calcium hydroxide and barium sulphate from isthmuses in 3D printed transparent root canal models.

Abstract

The purpose is to evaluate the efficacy of different irrigation techniques in the removal of various calcium hydroxide [Ca(OH)2] and barium sulfate [BaSO4] formulations from three isthmuses in 3-dimensional (3D) printed molar root canal models. 3D printed transparent models were designed, fabricated, and filled with pure Ca(OH)2 paste, Ca(OH)2-BaSO4 8:1 paste, Ca(OH)2-BaSO4 1:1 paste, pure BaSO4 paste, all in water, and Diapaste. Open-ended needle irrigation (ONI) at 5 and 15mL/min, double-side-vented needle irrigation (DNI) at 5mL/min, the GentleWave system (GW), PiezoFlow (PF), and passive ultrasonic activation (PUI) with distilled water, 0.5% sodium hypochlorite (NaOCl) and 3% NaOClwere used to remove the materials from the isthmuses. Ninety groups (n = 10) were established. The removal time was recorded from the start of irrigation to the completion of removal. GW and PF were the only methods that removed all tested materials from the isthmuses. PF required 2-3 × as much time as GW for complete removal, depending on the BaSO4 content of the paste. ONI at 15mL/min removed pure Ca(OH)2 paste, Ca(OH)2-BaSO4 (8:1) paste, Ca(OH)2-BaSO4 (1:1) completely but could not completely remove pure BaSO4 paste and Diapaste. PUI with intermittent needle irrigation, ONI, and DNI at 5mL/min were not able to completely remove any of the materials within 7.5min. The GW removed all materials faster than PF, whereas other methods failed to remove all materials from the isthmuses. Pure Ca(OH)2 and the mixture with BaSO4 paste in the proportion 8:1 were removed in less time than the other mixtures by the GW, PF and ONI systems, the latter only when using 15mL/min flow rate.