Efficacy of photon‐initiated photoacoustic streaming on apically extruded debris with different preparation systems in curved canals

Aim To determine the effect of photon‐initiated photoacoustic streaming (PIPS) on the extrusion of debris using multiple‐file (ProTaper Next‐PTN) and single‐file (One Shape‐OS) continuous rotary systems in curved canals in human molar teeth. Methodology Sixty extracted maxillary first molar teeth with curved mesial roots, mature apices and of similar lengths were selected. Teeth having canals with apical diameters larger than size 15 were discarded. The teeth were randomly divided into four experimental groups (n = 15 teeth per group) according to the file used and irrigation systems: (i) OS with PIPS with a 2940 nm Er:YAG laser (0.3 W, 15 Hz, and 20 mJ), (ii) OS with conventional needle irrigation (CNI) with a 27‐G needle, (iii) PTN with PIPS and (iv) PTN with CNI. The PIPS and CNI was applied during each file change for 20 s. Total irrigation and activation time was 1 min, and a total volume of 7.5 mL of bidistilled water was used as the irrigant. The apically extruded debris was collected into pre‐weighed Eppendorf tubes. The tubes were then stored in an incubator at 70 °C for 5 days. The weight of dry extruded debris was assessed by subtracting the initial weight of the tube from the final weight. The results were analysed statistically using one‐way analysis of variance and Tukey's post hoc tests. Bonferroni correction was used to compare the groups. Results The PIPS irrigation technique was associated with significantly more debris extrusion than the CNI system (P 0.05). The total amount of debris extruded apically by PIPS activation was significantly greater than that by CNI (P