Effect of precipitate formation in the root canal on the accuracy of electronic apex locators.

Purpose: This study evaluated how the formation of various types of precipitates affects the accuracy of electronic apex locators in determining the working length.

Methods: Two hundred and forty extracted human maxillary incisors were selected. A total of eight groups were used: four groups (n = 30) for the application of different irrigants; saline, sodium hypochlorite (5.25% NaOCl), chlorhexidine (2% CHX) and ethylenediaminetetraacetic acid (EDTA) (17% EDTA), and four groups (n = 30) for the formation of precipitates; orange-brown (2% CHX + 5.25% NaOCl), orange-white (2%CHX + 0.16% NaOCl), white milky (2% CHX + 17% EDTA), salt (2% CHX + saline). Electronic working length was determined by two different electronic apex locators.

Results: The success rate of the 5.25% NaOCl group was significantly higher than that of the white milky precipitate group. The electronic apex locators were highly effective in identifying working length, but the success rate of both devices declined due to the production of a white milky precipitate.

Conclusion: The study emphasizes the importance of selecting appropriate irrigation protocols for optimal treatment outcomes, as the chemical interactions between solutions and precipitates significantly influence electronic apex locator measurements, highlighting the need for careful consideration of irrigant compatibility.