Assessment of Apical Extrusion of Irrigation in Mandibular Molars during Application of the Novel Gentle Wave System in a Simulated Environment

Aim: This study assessed apical extrusion during treatment with GentleWaveTM (GW), conventional open-ended 30G needle (CN) or EndoVac® (EV) in root canals enlarged to different dimensions with and without apical constriction. Methodology: 16 mandibular molars were mounted in an in vitro apparatus. Roots were immersed in a pressure-regulated chamber containing distilled water with pressure kept at 5.88 ± 0.15 mmHg to simulate periapical back pressure. Mesio-buccal (curved ≤30o) and distal (straight) canals were instrumented to working length (WL) as follows: Minimal instrumentation (MI; #15/.04); traditional instrumentation (TI; #35/.06) or over-instrumentation (OI; #35/.06, to WL+1mm). Canals were tested 5 times each with distilled water using GW, CN (at WL-3mm) or EV and the mass (g) of extruded water recorded. Extrusion frequency and mean extruded mass were compared for each canal, irrigation group and canal instrumentation mode (Wilcoxon t-test; pM.Sc