Influence of gutta-percha solvents used in endodontic retreatment on the effectiveness of the Root ZX II apex locator

The aim of the present in vitro study was to determine the influence of different gutta-percha solvents used in endodontic retreatment cases on the accuracy of the Root ZX II electronic apex locator in locating the apical foramen. Thirty human, single-rooted permanent teeth were divided into three groups according to the solvent used: group OPO (orange peel oil, n = 10), group XYL (xylol, n = 10) and group CHL (chloroform, n = 10). Tooth length was established visually under 5× magnification with the aid of an optic microscope and then compared with the corresponding electronic measurement with a safety margin of ±0.5 mm. The results were analysed by the Biostat 4 program. The electronic and visual measurements coincided in 90% of the cases for xylol, in 100% of the cases for chloroform and in 100% of the cases for orange peel oil. No significant difference was observed among the three gutta-percha solvents in accurately locating the apical foramen (P = 0.607). Based on the results, it was possible to conclude that the accuracy of Root ZX II was not adversely affected by the presence of the gutta-percha solvents used in endodontic retreatment cases. Palabras clave: electronic apex locator, tooth length determination, working length