Accuracy of working length measurement with endo motor having built-in apex locator and comparison with periapical radiographs

Objective: To determine the accuracy of working length measurement with endomotor having built-in apex locator by comparing it with periapical radiographs. Methods: The cross-sectional study was conducted at the Department of Operative Dentistry, Dr Ishrat-ul-Ibad Khan Institute of Oral Health Sciences, Dow University of Health Sciences, Karachi, from January to June 2014, and comprised permanent maxillary anterior teeth with mature apices. A pre-operative radiograph was taken by using standardised paralleling technique. The access cavity was prepared by a high speed water-cooled diamond bur. After doing initial filing and drying the canal, the working length was taken with an endomotor with built-in apex locator in dual mode using the Protaper Rotary File S1. The length was measured using a millimetre scale. After attaining tentative working length from the pre-operative radiograph, 1mm was subtracted from the radiographic apex. A stainless steel K-file was placed in the canal at this length and a radiograph was taken by paralleling technique using intraoral film holder. The electronic and radiographic findings were noted. Accuracy was considered positive if the endomotor reading was 0-2mm short of the radiographic working length. Data was analysed using SPSS 16. Results: Of the 96 cases, working length with X-Smart Dual was acceptable in 85(88.5%) cases, and unacceptable in 11(11.5%) cases. Conclusion: Accuracy of working length measurement with endomotor having built-in apex locator was found to be a better measuring tool compared to the conventional periapical radiographs.