AN IN VIVO STUDY TO EVALUATE THE EFFICACY OF ELECTRONIC APEX LOCATORS IN THE DETERMINATION OF WORKING LENGTH

Abstract

Objectives:The aim of this study was to determine whether the performance of electronic apex locators can equal or outdo the radiographic technique and establish itself as a standard baseline entity for the determination of working length.
Methodology: One hundred and seventy five canals of 84 patients were included in this study at the Department of Operative Dentistry, Khyber College of Dentistry for the preparation phase of root canal treatment. The canals were dried and the Joypex 5 apex locator was used to record the working length. The patients were sent for a periapical radiograph and radiographic working length was calculated. Both values were recorded on specially designed proforma; the difference was noted and subjected to statistical analysis using a Paired-samples T test with a critical p-value of <0.05.
Results:Out of 175 canals measured, the radiographic working length coincided with the electronic working length in 101 (60.0%) cases. In 31 cases (17.7%), the electronic working length was short by 0.5mm and in 24 cases (13.7%) the electronic working length was over by 0.5mm. In 7 cases (4%) the electronic working length was short by 1mm and over by 1mm in 4 cases (2.3%). In 2 cases each, the apex locator underestimated the working length by 2 and 3mm (1.1 % each). Overall, the difference between the working lengths measured by the two methods was statistically insignificant (p = 0.294)
Conclusion: The difference between the two working lengths obtained was not significant (p = 0.294). The apex locator was able to locate the apical foramen to within ±0.5mm in 91.1% of the cases. However its solo application for determining working length is discouraged and must be used in tandem with conventional radiography.