[A comparative evaluation of Apex D.S.P. and Root ZX Apex locators. An in vitro study].

Introduction: In modern endodontics, no possibility of the root canal preparation is allowed, unless its length was individually determined. Only until recently, the length was assessed on the basis of the radiograph with the file placed into the root of the canal. However, apex locators have been in use for this assessment for some time. The newest ones, called the apex locators with different frequencies, in opposition to the classical ones, allow for accurate measurement even in teeth with wet content and periapical lesions. The aim of this in vitro study was a comparison of accuracy of two apex locators with different frequencies.

Material And Methods: Thirty single-rooted teeth were used in this study. After access cavity preparation, the actual canal length was determined, and subsequently they were placed in alginate impression material in order to perform measurements with Root ZX (Morita, Japan) and Apex D.S.P. (Septodont, France) apex locators. The obtained lengths were measured with endodontic ruler.

Results: Length concordance with the actual canal length for Root ZX apex locator was 93.3%. In two cases, electronic measurement was inaccurate--one too short and one too long. For Apex D.S.P. device precise measurements were obtained in 90% of cases with 10% of results being too long if compared to the actual values. Statistical analysis did not disclose significant differences between the measurements. Length value comparison, for the assessed apex locators, allowed to confirm result concordance in 28 of 30 measurements (93.3%). In 2 remaining cases, lengths determined by the Apex D.S.P. device were 1 mm longer than the values for Root ZX apex locator.

Conclusions: Root ZX and Apex D.S.P. apex locators allow for relatively accurate assessment of the root canal length. Precision of these two devices is comparable.