A Study on the Rate of Irrigant Penetration to the Apical Third of the Root Canal via Urografin Injection

Penetration of irrigants to the apical third of the root canal for removing debries from the apical portion depends on the final size of preparation. Larger-sized apical preparation can substantially reduce the amount of bacteria in the apical third. The purpose of this study was to determine the minimum size of canal preparation to influence irrigant material penetration to the apical third using urografin. A total of 84 canals from 42 mesial roots of human first mandibular molar were selected and divided into four study groups. The technique of instrumentation was step-back and the final size of master apical file (MAF) was #20 in group 1, #25 in group2, # 30 in group 3 and #35 in group 4. After the final irrigation of the canals with sodium hypochlorite and drying with paper points, the contrast media, urografin penetration rate in the apical third of canals were measured and compared through RVG digital radiography system. Data were analyzed using analysis of variance and Tukey post-hoc test.(α=0.05) Contrast material penetration rate increased when apical preparation size was larger. However, there were no significant differences between #20 and #25 files groups and also between #30 and # 35 files groups. (p>0.05) It seems that preparation with #30 files is minimum recommended size for the best penetration of irrigants to the apical third of the root canal.