Deviation in Simulated Curved Canals Prepared with Reciproc and ProTaper Systems

The incidence of deviation in simulated curved canals was compared after preparation with nickel-titanium instruments driven by continuous rotation and reciprocal movement motors. A total of 40 epoxy resin blocks were filled with ink, and pre-instrumentation images were obtained by a stereomicroscope. Instrumentation was performed using either Reciproc (R25) or ProTaper (up to F3). Post-instrumentation images were obtained under the same conditions as those of the previous images, and then, images were superimposed. Differences along and on the mesial and distal surfaces of the canal were measured in 8 points. Intragroup analysis demonstrated that the two systems promote deviations along the 8 points of measurement in the canal. Within the ProTaper group, significant differences (P < 0.01) with greater deviations were at the following points: 4 mm >7 mm >3 mm >6 mm. In Reciproc group, significant differences (P < 0.05) were found at points: 3 mm >4 mm >2 mm >1 mm. ProTaper group presented smaller deviation at points: 0, 2, 3, 4, and 6 mm compared with Reciproc group. The results suggest that continuous mechanized instrumentation with previous and progressive cervical preparation in the apical direction, with specific files, tends to perform a more adequate preparation with less risk of displacing the original canal when compared with a single instrument with reciprocal movement.