[The effect of curvatures on the accuracy of the electronic apex locator].

Purpose: To investigate the effect of canal curvatures on the accuracy of 3 electronic apex locators (EAL) in vitro.

Methods: Alginate and 123 canals were used to mimic the situation in vitro. Three kinds of electronic apex locators including Raypex5(®), Propex(®) and Rider(®) were applied to determine the length of the canals divided into 3 groups including straight (<5°), middle (>10°,<20°) and severe (>20 °) according to the root canal curvatures. Experimental measurements and the distances (IF value) between experimental and ideal actual measurements under the same measurement environment were recorded. Paired sample t test was applied to analyze the results by using SPSS11.5 software package.

Results: The results showed that with the allowance of ±0.5 mm, the accuracy ratios of straight canal, moderate and severe curvature canal were 84.6%, 81.6%, 87.5% for Raypex5(®) 76.9%,89.8%, 91.7% for Propex(®), and 92.3%, 89.8%, 87.5% for Rider(®), respectively. There was no significant difference in the accuracy between the EALs regarding three degrees of root canal curvatures.

Conclusions: The curvatures of the root canals have no influence on the accuracy of the EALs, though the difference exists in the accuracy rate among the EALs.