Remoção de detritos de raízes mesiais de molares inferiores com istmos proporcionada por diferentes volumes de irrigação e insertos ultrassônicos: estudo laboratorial por microtomografia computadorizada

Abstract

The present study compared the effect of using different irrigating solution volumes, 6 ml or 30 ml, and two ultrasonic tips, Irrisonic and Irrisonic Power, in the removal of hard tissue debris (HTD) from the main canals (mesiovestibular and mesiolingual) and root isthmus of mesial roots of human lower molars. Sixty mesial roots of mandibular molars were selected after preliminary computerized microtomography scanning. Coronary access was performed and then WaveOne Gold Medium instruments were associated with a 2.5% sodium hypochlorite solution to perform the chemical-mechanical preparation perfomed up to 1 mm of the apical foramen. Subsequently, post-preparation scans were performed to confirm the presence of HTD and its quantification. The specimens were then randomly divided to perform the passive ultrasonic irrigation protocols: Irrissonic/6 ml tip (IR6), Irrissonic/30 ml tip (IR30), Irrissonic Power/6 ml tip (IRP6) and Irrissonic Power/30 ml tip (IRP30); the control received only conventional irrigation. Once the procedures were completed, new scans allowed the calculation of the percentage of HTD removal provided by the protocols employed. The ANOVA and Tukey tests were applied in the comparison between the groups and the t-Student test for comparisons between the evaluated factors, tip/volume; a significance of 5% was established. The highest percentage of HTD removal among the experimental groups was observed in RI30 (87.63%) and the lowest in RI6 (80.16%); the control group had the lowest HTD removal (74.23%). Statistical analysis showed significant differences between the experimental and control groups (P <0.05), with the exception of IR6 (P =0.0623). Considering the variables tested separately, tip and volume of solution, only the volume of solution was able to positively influence the removal of HTD (P = 0.0095). In the regard, under the conditions of the present study, it is possible to state that the use of a greater irrigating solution volume during passive ultrasonic irrigation significantly influenced the efficiency of debris removal from the interior of canals and isthmus of mesial roots of mandibular molar teeth. Additionally, it was observed that the Irrisonic Power tip did not influence the results.