(PR096) Determine the Accuracy of 2 Electronic Apex Locators in C-shaped Canals by Using Micro-Computed Tomography

Objectives: There is a lack of knowledge regarding the accuracy of electronic apex locators in C-shaped canals. This study aims to evaluate the accuracy of two EALs, Root ZX II (JMorita, Japan) and Raypex 6 (VDW GmbH, Germany), in C-shaped canals of extracted mandibular molars using micro-computed tomography (micro-CT) scanning. The null hypothesis is that there is no difference in accuracy between these two EALs.

Methods: 43 extracted human mandibular molars with C-shaped canals were selected and prepared. The actual root length was measured visually by placing a #10 or #15 K-file up to the apical foramen (AF) under a microscope at 10x magnification. Measurements from the EALs at the “APEX/0.0” and “0.5 mark” lines for Root ZX II, and the “Red bar” and “Third green bar” lines for Raypex 6, were recorded as the electronic root canal length and the electronic working length. The position and diameter of the apical foramen (AF), position and diameter of the apical constriction (AC), distance between the AC and AF, and presence or absence of accessory foramen were recorded from the micro-CT scans.

Results: The study included 127 canals. Preliminary data showed that Root ZX II and Raypex 6 produced electronic readings within the ±0.5 m range 87% and 78% of the time, respectively. A statistically significant difference in precision between Root ZX II and Raypex 6 was found (Z test, p=0.043).

Conclusion: Within the limitations of this in vitro study and preliminary data, Root ZX II demonstrated high accuracy in determining the actual root length compared to Raypex 6.