Changing in Working Length and Canal Dimension Following Instrumentation with Hand and Rotary Instrument

Aims: This udy evaluated changes in working length (WL) and root canal dimension after inrumentation with hand inruments (St.St, NiTi) and rotary syems (RaCe, ProTaper). Materials and Methods: Twenty four resin blocks with a curve canal of 33angle at (14mm) were selected for this udy. Working length was measured by a digital measurement using a number (10k) le under ereomicroscope at 40X. The specic sequence of inrumentation was syem according to manufacturers recommendation. The working length of the canal was measured again between each le and at the end of inrumentation. Pre and po-inrumentation microscopic photographs were taken and measurements of the root canal dimension change were measured with an image analysis programme . The dierence in working length was analyzed using ANOVA and Duncans te at 5% level of signicance. Result: Statiical analysis showed that there was no signicance dierence in the changing of the working lengths and canal dimension between the two rotary syems (ProTaper,RaCe). While there was a signicant dierence in the changing of the canal length and dimension between the two rotary syems (ProTaper,RaCe) and the hand inruments (St.St, NiTi). The amount of variation in working length and canal dimension obtained with both types of rotary inruments, was signicantly less than that produced by hand inruments. Conclusion: The variation in working length were clinically not very signicant between the two rotary NiTi inruments (ProTaper, RaCe)while it was signicant with the hand inrument (St.St and NiTi).