Standardization of Variable Taper Files and Corresponding Gutta-Percha Cones Amongst Manufacturers.

Introduction: Currently there is no standardization of variable taper endodontic files and corresponding gutta-percha (GP) cones. The aim of this study was to evaluate intramanufacturer and intermanufacturer variability of diameter and taper in the apical third of GP master cones and finishing files from 3 commercially available variable taper endodontic systems.

Methods: Diameter measurements were recorded using digital microscopy at 1-mm increments (D1-D4) for F2 files and corresponding GP cones (n = 20 per system) from ProTaper Gold (Dentsply Tulsa Dental Specialties, Johnson City, TN), EdgeTaper Platinum (EdgeEndo, Albuquerque, NM), and ExactTaper H (SS White, Lakewood, NJ). Taper was defined as the rate of change in diameter per 1-mm increment. Mean differences in diameter were assessed using repeated measures of analysis of variance for D1 to D4 and the Wilks test for differences in taper.

Results: In the apical third, ProTaper and EdgeEndo mean file diameters were significantly smaller than corresponding GP cone diameters (P < .01, P < .01, respectively). Contrastingly, SS White file diameters were significantly larger than their corresponding GP cones (P = .02). Files from all manufacturers had significantly smaller diameters than advertised (nominal) values (P < .01). ProTaper GP cones had similar diameters to nominal values (P = .30), while EdgeEndo and SS White GP cones were significantly smaller (P < .01). Amongst files and corresponding GP cones from all systems, taper was nonstandardized.

Conclusions: Size discrepancies between finishing files and corresponding GP cones can be expected amongst variable taper endodontic systems. Therefore, clinicians should be prepared to make intraoperative adjustments when obturating.