Influence of cervical preflaring on apical transportation in curved root canals instrumented by reciprocating file systems

Background: The aim of this study was to evaluate the influence of cervical preflaring on apical transportation in curved root canals prepared using the Reciproc and WaveOne reciprocating file systems. Methods: Sixty curved canals were instrumented using Reciproc R25 and WaveOne Primary files, with and without preflaring (n = 15). A double-digital technique was used to digitally superimpose the file before instrumentation (#15 K-file) on the final apical reciprocating file (#25/08). The angle between the tip of the initial and final file was measured and recorded. Groups were compared using the Kruskal-Wallis test, and significance was set at p<0.05. Results: The mean and standard deviation for apical transportation was 0.93 +/- 2.48 for the Reciproc Group, 0.84 +/- 1.94 for the Preflaring+Reciproc Group, 0.40 +/- 1.14 for the WaveOne Group, and 0.83 +/- 2.20 for the Preflaring+WaveOne Group. No statistically significant differences were found among the groups (p=0.9509). Conclusions: Under the conditions of this study, cervical preflaring did not influence apical transportation in curved root canals instrumented using Reciproc R25 and the WaveOne Primary files. Based on the in vitro measurements of apical transportation, the reciprocating files may be used without preflaring in curved root canals.