Spectrophotometric Analysis of Apical Extrusion of Sodium Hypochlorite using Different Irrigation Protocols in an Ex Vivo Model of Immature Teeth.

OBJECTIVE: To evaluate the effect of different agitation methods on apical extrusion of 1.5% sodium hypochlorite (NaOCl) in an ex vivo model of immature teeth. METHODS: Sixty extracted human inferior incisors were prepared to simulate immature teeth and embedded in an artificial root socket made of silicone impression material. The teeth were then divided into four groups: Conventional needle irrigation (CNI) alone, CNI supplemented with Ultrasonic Irrigant Activation (UIA), EasyClean (EC), or XP-endo Finisher (XPF). Extruded NaOCl was collected, reacted with m-cresol purple, and its absorbance values were measured. The data were statistically analyzed using One-way analysis of variance with a significance level of 5%. RESULTS: All groups showed apically extruded irrigating solution, and the mean volumes of extruded NaOCl did not differ significantly between any of the test groups (p⟩0.05). CONCLUSION: The activation of 1.5% NaOCL by UIA, EC, or XPF as supplementary to CNI does not promote greater apical extrusion when compared to CNI alone in simulated immature teeth.

Clinical efficacy of EDTA ultrasonic activation in the reduction of endotoxins and cultivable bacteria.

AIM: This clinical study was conducted to investigate the influence of 17% ethylenediaminetetraacetic acid (EDTA) ultrasonic activation after chemomechanical preparation (CMP) on eliminating/reducing oral bacterial lipopolysaccharides (known as endotoxins) and cultivable bacteria in teeth with pulp necrosis and apical periodontitis. METHODOLOGY: Samples were taken from 24 root canals at several clinical periods: S1 - before CMP; S2 - after CMP; S3 - after EDTA: G1 - with ultrasonic activation (n = 12) and G2 - without ultrasonic activation (n = 12). Root canals were instrumented using Mtwo rotary files. Culture techniques were used to determine the number of colony-forming units (CFU). Limulus amebocyte lysate (LAL) was used to measure endotoxin levels. Friedman's and Wilcoxon signed-rank tests were used to compare the amount of bacteria and endotoxin levels in each period (P < 0.05). RESULTS: Endotoxins and cultivable bacteria were recovered in 100% of the initial samples (S1). CMP was effective in reducing endotoxins and bacterial load (all with P < 0.05). Higher values of endotoxin reduction were achieved with EDTA ultrasonic activation [G1, 0.02 EU mL-1 (range 0.01-0.75)] compared with the no activation group [G2, 1.13 EU mL-1 (range 0.01-8.34)] (P < 0.05). Regarding bacterial reduction, no statistically significant difference was found in S3, regardless of the group (G1, G2, P > 0.05). CONCLUSIONS: Chemomechanical preparation was effective in reducing bacteria and endotoxins, but could not completely eliminate them. The ultrasonic activation of EDTA was effective in further reducing endotoxin levels in the root canals of teeth with pulp necrosis and apical periodontitis.