CUTTING PATTERN OF NICKEL-TITANIUM FILES USING 2 PREPARATION TECHNIQUES

The aim of this study was to examine the cutting patterns of recently introduced nickel-titanium endodontic files and compare them with simi larly shaped stainless steel files using both balanced-force and stepb ack techniques. Simulated canals were constructed in resin blocks with 40 degrees curvature. Fifty blocks were prepared by a balanced-force technique: 25 with Nitiflex (Maillefer) and 25 with Flexofiles (Maille fer) to a master apical file size 40. Fifty blocks were prepared by a stepback technique: 25 with Nitiflex and 25 with Flexofiles to a maste r apical file size 30. Composite prints were made of pre-and post-inst rumentation canals using a computerized imaging system. The amount of material removed from the inner and outer canal curvatures was measure d at eight levels in the apical 11 mm of the canal. The results were a nalysed by Kruskal-Wallis ANOVA. Using the balanced-force technique, N itiflex files removed less material on the outer curve apically and le ss on the inner curve mid-canal (P<0.05), while Flexofiles caused more apical transportation. In the stepback technique, the Nitiflex files removed more material from the outer curve apically (P<0.05); the Flex ofiles removed more material along the entire inner curve (P<0.05), an d maintained canal curvature better than Nitiflex files. It appeared p referable to use Nitiflex files in a balanced-force technique, and Fle xofiles in a filing technique as stainless steel files can be precurve d.