RESUMO
Objective@#This ex vivo study evaluated the effect of ultrasound and Er:YAG laser irrigation activation techniques on the penetration of sodium hypochlorite solution into infected human root canal dentin, providing a reference for clinical infection control of infected root canals.@*Methods @#Thirty-six cases of infected root canals were collected and randomly divided into three groups according to the irrigation technique: 12 cases in the conventional syringe irrigation (CSI) group, 12 cases in the passive ultrasonic irrigation (PUI) group, 12 cases in the Er:YAG laser and photon-induced photoacoustic streaming (PIPS) group and 36 cases of clean root canals (12 cases in the CSI group, 12 cases in the PUI group, 12 cases in the PIPS group). All of the selected root canals were straight root canals of posterior teeth. After standardizing the root length, all canals were subjected to instrumentation and dynamic irrigation. 2% methylene blue solution was used to visualize the penetration of the irrigant. EXAKT cutting and grinding equipment was used to take transverse sections of 100-150 μm at the coronal, middle and apical thirds of the root canals. The data (maximum penetration depth, average penetration depth, and penetration percentage) were observed under a light microscope to evaluate the effect of dye penetration. @*Results @# With the three irrigation techniques, the maximum penetration depth, average penetration depth and penetration percentage of the infected root canals were significantly lower than those of clean root canals in the full length of the root canal (P<0.05). The penetration percentage, average penetration depth and maximum penetration depth of the PIPS group were significantly higher than those of the CSI group in the coronal, middle and apical thirds of the infected root canal, respectively (P<0.05). There was no significant difference in the maximum penetration depth, average penetration depth or penetration percentage between the PUI and CSI groups (P>0.05). There was also no significant difference in the maximum penetration depth, average penetration depth or penetration percentage between the PIPS and PUI groups (P>0.05). @*Conclusion @# The dentine permeability of infected root canals was weaker than that of clean root canals. Er:YAG laser-assisted irrigation activation technology could significantly improve the penetration of sodium hypochlorite solution into infected dentin, but passive ultrasonic irrigation did not significantly improve the penetration.
RESUMO
El agente irrigante debería alcanzar la totalidad del conducto radicular, inclusive las zonas más apicales, para mejor la limpieza y desinfección. Sin embargo existe el riesgo de la extrusión del mismo a los tejidos periapicales. El presente estudio con diseño experimental tuvo el objetivo de evaluar la extrusión apical del agente irrigante endodóntico de acuerdo a la técnica de irrigación durante la irrigación final en dientes naturales, ex vivo. Se utilizaron 46 dientes anterosuperiores naturales extraídos con conducto único y las raíces se sumergieron en una gelatina conductora incolora. Una aguja de irrigación/aspiración fue colocada a 2 mm de la longitud de trabajo y se irrigaron los conductos con una solución de contraste a 4 ml/min durante 60 s. En 18 dientes se utilizó la técnica de irrigación por jeringa y en los 18 restantes se utilizó la técnica por presión negativa. Los controles positivos y negativos estaban compuestos por 5 dientes cada uno. Se evaluaron presencia y área de extrusión. La prueba Chi2 encontró una asociación estadísticamente significativa (p <0,001) entre la presencia de extrusión y la técnica de irrigación. El área mediana de extrusión provocada por irrigación por jeringa (0,645 mm2) fue estadísticamente mayor a la provocada por la irrigación por presión negativa (0 mm2) (U Mann Whitney, p <0,001). Se concluyó que la irrigación por presión negativa produce menos extrusión de la solución irrigante, no sólo en frecuencia sino también en área de extrusión comparado con la irrigación por jeringa.
Root canal irrigants should be able reach the entire root canal system, including the mostapical portions, in order to achieve better cleaning and disinfection. However, there exists arisk of irrigant extrusion to the perirradicular area. The present study had an experimentaldesign with the purpose of evaluating irrigant apical extrusion of the endodontic irrigantaccording to the irrigating technique during final irrigation y extracted human teeth, ex vivo.Forty six anterior upper single canaled teeth were used and the roots were embedded into aconducting transparent gel. An irrigating/aspirating needle was placed 2 mm from workinglength and irrigation was performed with a contrast solution at 4 ml/min during 60 s.Eighteen teeth were used for syringe irrigation and negative pressure irrigation each Additionally, 5 teeth were used for positive and negative controls, each. The presence andextrusion area were evaluated. The Chi2 test found a statistically significant asociation (p <0,001) between extrusion and irrigation technique. The median area of extrusion by syringeirrigation (0,645 mm2) was statistically greater than that by negative pressure irrigation (0mm2) (Mann Whitney U, p <0,001). In conclusion, the frequency and extent of extrusioncaused by negative pressure irrigation was less compared to syringe irrigation.