[Effect of four different solutions on the accuracy of electronic apex locators].

Purpose: To investigate four different solutions on the accuracy of two electronic apex locators (EAL) in vitro.

Methods: 1% agar and extracted single-canaled tooth were used to mimic the situation in vivo. Forty-seven teeth were used. Two kinds of electronic apex locator, Raypex 5 and TRRY , were applied to determine the length of the canals being flooded with four different solutions. Experimental measurements and the distances(IF value) between experimental and ideal actual measurements under the same measurement environment were recorded. Paired sample t test were applied to analyze the results by using SPSS10.0 software package.

Results: While the canals were flooded with 0.9% NaCl, 5.25% NaOCl, human blood and 17%EDTA, the ratios of the distance within limits of +/-0.5mm were 91.5%, 91.5%, 100% and 97.8% for Raypex 5 and 95.7%, 93.5%, 93.5% and 84.8% for TRRY , respectively. There was a significant difference in accuracy between two EALs regarding blood and 17% EDTA (P<0.05).

Conclusions: Both Raypex 5 and TRRY can measure root canal length accurately despite the influence of solutions under this experimental environment.