Maria Alejandra DIAZ ESQUIVEL, Antonio J. CONDE VILLAR, Gaizka LOROÑO, Alfonso Martín ESCORIAL, Beatriz TEJEDOR, Ruth PEREZ-ALFAYATE, Giampiero ROSSI-FEDELE, Roberto ESTEVEZ
European Endodontic Journal - 2026;11(9):448-452
Objective: The effect of intracanal heating (IH) combined with ultrasonic agitation on the organic tissue-dissolving ability of sodium hypochlorite (NaOCl) in the peripheral areas of the root canal system remains unexplored. This in vitro study evaluated the ability of 2.5% NaOCl, with IH and/or ultrasonication (US), to dissolve porcine palatal tissue within standardized simulated grooves in roots of human maxillary central incisors. Methods: The root canals of 105 decoronated human maxillary central incisors were chemo-mechanically prepared and the teeth split. A standardized longitudinal intracanal groove was created in 1 of the root halves; porcine palatal mucosa samples were collected, adapted to fit into the grooves, and weighed. The reassembled samples were randomly divided into 3 experimental groups and positive/negative controls (PC/NC) n = 21 each. Sodium hypochlorite was delivered using a syringe and needle positioned 2 mm short of the working length. The intervention protocols were as follows: IH: 2 cycles at 150 dereceC for 10 seconds each; US: 2 cycles at high frequency for 10 seconds each; and combined IH+US: 1 cycle of each adjunct. Specimens were submerged in 37 dereceC water bath. Percentage tissue dissolution was compared among groups using one-way analysis of variance (ANOVA), and pairwise comparisons were performed with the Tukey post-hoc test. The level of significance was set at P = .05. Results: The mean (SD) percentages of tissue dissolution were as follows: PC: 95.2 (4.3); IH: 38.7 (10.1); IH+US: 32.2 (11.4); US: 26.5 (10.9); NC: 1.8 (0.9). A significant difference was observed between IH and US (mean difference = 12.2%; P = .008). No further significant differences were detected among the experimental groups. Conclusions: Within the limitations of this laboratory study, IH resulted in greater tissue dissolution in simulated grooves than ultrasonic agitation alone, whereas the combined IH+US protocol showed intermediate values and did not differ significantly from either technique.
