RESUMEN
This study was done to evaluate transportation of the apical foramen after 0.5 mm overinstrumentation by ProFile, ProTaper and K3 in simulated resin root canal. Sixty simulated resin root canal with a curvature of J and S-shape were divided into two groups. Each group consisted of three subgroups with 10 blocks according to the instruments used: ProFile(R), ProTaper(TM), and K3TM. Simulated resin root canal was prepared by ProFile, ProTaper and K3 with 300 rpm by the crown-down preparation technique. Pre- and post-instrumentation apical foramen images were overlapped and recorded with Image-analyzing microscope 100X (Camcope, Sometech Inc, Korea). The amounts of difference in width and dimension on overlapped images were measured after reference points were determined by Image Analysis program (Image-Pro(R) Express, Media Cybernetic, USA). Data were analyzed using Kruskal-Wallis and Mann-Whitney U-test. The results suggest that ProFile showed significantly less canal transportation and maintained original apical foramen shape better than K3 and ProTaper.