The comparative effectiveness and safety of three activated irrigation techniques in the isthmus area using a transparent tooth model.

AIM: To compare the effectiveness and safety of three activated irrigation techniques when removing pulp tissue from the isthmus of a transparent tooth model. The three techniques assessed were: the EndoVac (EV), passive ultrasonic irrigation (PUI) and ultrasonic wave aspiration (TUWA). Conventional syringe irrigation (CSI) was used as a control. METHODOLOGY: A transparent tooth model was created using the mesial root of an extracted mandibular first molar that had an isthmus and two independent mesial canals. An artificial 0.3-mL cylindrical chamber was created below the apical foramen. The tooth was then cleared. After preparation, the root canals were filled with fuchsine-stained bovine pulp tissue. The irrigation protocols were compared in respect of their effectiveness at removing pulp tissue from the isthmus and their safety with regard to irrigant extrusion. For all four groups, 5.25% sodium hypochlorite solution was used as the irrigant. Photographs were taken and analysed using an imaging software. A Kruskal-Wallis test was used to detect the differences between groups (statistical significance was set at P < 0.05). RESULTS: No group was associated with extrusion of irrigant beyond the apex. Significant differences were observed between the groups: TUWA was the most effective technique at removing pulp tissue from the isthmus (3.39 mm2 ; standard deviation (SD) = 0.67; range = 1.25-3.69), followed by PUI (2.16 mm2; SD = 0.38; range = 1.37-2.96), EV (0.73 mm2 ; SD = 0.14; range = 0.49-0.98) and CSI (0.27 mm2 ; SD = 0.01; range = 0.26-0.28). CONCLUSION: Ultrasonic wave aspiration was the most effective technique at removing artificial pulp tissue from the isthmus of a transparent tooth model. None of the techniques extruded irrigant.

A technique for placement of apical MTA plugs using modified Thermafil carriers for the filling of canals with wide apices.

AIM: To describe a technique for the placement of apical Mineral trioxide aggregate (MTA) plugs in canals with wide apices. SUMMARY: A novel technique to fill root canals with an apical diameter larger than 0.4 mm is presented. The technique includes three main stages; three Thermafil carriers of increasing size, previously de-sheathed by removing the Gutta-percha coating, are selected to engage 1, 2 and 3 mm short of the apex. Their use allows the negotiation of acute curvatures and ledged canals. Subsequently, an MTA plug matching the apical gauge is pre-formed with a pellet block, placed and condensed using the modified carriers in sequence. The presented protocol for the management of teeth with apices of a diameter greater than 0.4 mm allows a favourable apical control of the MTA. Clinical cases completed using this methodology are presented. KEY LEARNING POINTS: MTA placement in teeth with wide apices was facilitated by using de-sheathed Thermafil carriers, to create an appropriate seal and stable platform for Gutta-percha backfilling or subsequent fibre post placement. The use of de-sheathed Thermafil carriers of different sizes allows predictable placement of pre-formed MTA plugs. Gauging of Thermafil carriers enhances control of the condensation phase to limit the extrusion of MTA.