Objectives: The aim of the present study is to compare apical transportation, centering ratio, changes in working length and canal axis ratio in the S-shaped canals using full rotation versus reciprocation shaping techniques.
Methodology: Twenty-five S-curved artificial canals were used. Five canals were used for the pre-instrumentation radiographs and records. The other 20 canals were divided into two groups (10 canals each); G1: One-Shape (OS) and G2: Wave-One (WO) files. Canals were prepared, and obturated. Post-obturation radiographs were taken with the same parameters of the pre-instrumentation records. Pre- and post-instrumentation digital images were evaluated with AutoCAD program analysis.
Results: Full rotation using OS files showed significantly far less apical transportation than WO reciprocation (P < 0.001). There was no statistically significant difference in centering ratio between full rotating and reciprocating files (P > 0.05). WO produced higher percentage increase in working length than OS files. Both techniques could not maintain the original canal
axis ratio.
Conclusions: Within the parameters of this study, Single-file shaping technique with full rotation instruments produced significantly less transportation and less violation of the working length than did the reciprocating WO instruments. Both techniques violated the original canal axis ratio and had nearly equal centering ratio, however, none of them was perfectly centered.