The effect of master apical file size with variable & constant taper on irrigation & cleaning of the apical third of the curved

The size, taper & cross-section of an instrument plays a crucial role in cleaning the apical third of a root canal which has a significant amount of debris & smear layer (SL). The purpose of this study was to evaluate the cleaning efficacy of different sizes and tapers of the MAF (Master Apical File) for penetration of irrigants to the apical third of curved mesiobuccal (MB) canals of first molars. Materials and Methods: 75 teeth were divided into 5 rotary instrumentation groups (n=14) ProTaper Universal MAF: 20.07 (group1), 25.08 (group2), 30.09 (group3) & K3XF MAF: 25.06 (group4), 30.06 (group5) and a non-rotary instrumentation group (n=5) which served as a control : 20.02 (group6). After instrumentation groups were rinsed with 2 ml of 3% NaOCl for 2 mins & 2ml of 17% EDTA for 1min twice & final flushing with 5 ml of normal saline. In controls only 5ml of saline was used. Efficacy of debridement of the canal was evaluated using Scanning electron microscopy (SEM). The data was analysed using the Post- Hoc & One-way ANOVA & Chi-square test. Results: Groups 30.09, 30.06, 25.08 showed cleaner canals when compared to groups 20.02, 25.07, 25.06 for both debris & smear layer (p<0.05).Although group 30.09 showed the best results followed by group 30.06 & group 25.08 the difference however between these three groups was not statistically significant. Conclusion: Within the limitations of the study the minimum appropriate and acceptable debridement was achieved with MAF=25.08 in the curved canals.