Comparative Study Of The Apical Transportation Among Three Instrumentation Techniques

Objective: To use a newly developed radiographic technique to compare apical transportation among manual Protaper , K3 rotary instrument and Stainless Steel(SS)-K file in vitro.Materials and methods: Mesio-buccal canals of 51 extracted mandibular first molars were randomly divided into three groups. Group 1 was instrumented with SS-K files by step-back technique, group 2 was instrumented with manual Protaper instruments according to manufacturers' directions. A specially constructed radiographic jig with a RVG radiographic system was used to take pre- and postoperative radiographs of the samples at predetermined angulations to get the X-ray images of both the root canal maximum curvature and minimum curvature. Using AutoCAD2004, the central axes of initial and final instruments were radio-graphically superimposed to determine the degree of apical transportation at D0.5, D1, D2, D3, D4, D5 apical level from the WL. Data were analyzed using anova.Results: no statistically significant difference in apical transportation was found at every apical level between group2 and group3; a statistically significant difference was found at the D0.5,D1,D4,D5 level except D2,D3 level between groupl and group2 or gruop3. In group 1, a statistically significant difference was found at the D0.5, D1, D4, D5 level between the max curvature and min curvature. Only at the D4, D5 level in group2, a statistically significant difference was found between the two curvatures.Conclusions: the result indicate both manual Protaper and K3 rotary instrument are comparable to each other in regards to their ability to optimally enlarge root canal with minimal apical transportation but the SS-K file had obvious apical transportations in the plane of root max curvature. The curvature of root canal has no obvious influence on the manual Protaper and K3 but will influence the SS-K file.