The objective of the present investigation was to compare the precision of canal working length (Ll) measurements by electronic and radiological methods.
Materials and method: The study was developed on a group of 122 anterior teeth of 118 patients, with ages between 23 and 58 years. The teeth were divided into 3 groups. The first one included 45 teeth, for which the working length was calculated with an electronic device (Apex Locator model iPex, NSK, Japan). In the second group of teeth (39 in all), the working length was calculated by the radiographic method of Ingle and, in the third one (38) – by the method of Bregman. When the technique of canal modeling was applied to all groups of teeth, a primary gutta percha cone (master) was positioned on the canal at the exact working length calculated for each tooth in part, after which an intra-oral radiography was made and the distance between the apical end of the master cone and the apical constriction was measured.
Results: In group I, 91.1% of the Ll measurements were exact, and 8.9% of them were shorter, yet remaining within the limit of 2 mm versus the apical constriction. In group II, 71.7% of Ll were correctly measured, in 5.1% of the cases the calculated length was higher and in 23.2% of them the obtained values led to sub-obturation. Out of the inexact measurements, 44.4% evidenced the tip of the master cone within the limit of 2 mm versus the apical stricture. In group III, 60.5% of the measurements gave exact results, 13.1% of them – higher and 26.4%, respectively – lower. 53.8% of the cases of over- or sub-instrumentations occurred within the limit of 2 mm versus the apical constriction
Conclusions: The method for the calculation of working length with an electronic device of apical localization appeared as the most correct one, being followed by the radiographic technique of Ingle and by the method of Bregman. Application of the electronic method showed no case of apical over-instrumentation, while the sub-instrumentation cases were within the limit of the apical 2 mm, considered as accepted limits. The highest number of both over-instrumentation and sub-instrumentations was registered with the Bregman method.
- Bregman radiographic method
- canal working length
- electronic method.
- Ingle radiographic method