Comparison between apex locater and conventional radiography in working length determination of maxillary first molars: a clinical study

Abstract

Aim of the study: The purpose of this study is to compare the working length (WL) measurement results of conventional periapical radiographies and electronic apex locater (EAL).
 Materials and method: This study was conducted during sessions of root canal treatment of 10 patients diagnosed with acute pulpitis. A total 30 root canals measurement (ten 1st upper molars, each with 1 palatal canal and 2 buccal canals) were included in the data analysis. A linear correlation and linear regression tests were utilized to check for a linear association between apex locator and X-ray measurements. Measurements of all roots were first included in the linear correlation test, and then measurements of each type of roots (palatal, mesio- buccal and disto- buccal) were tested separately. Significant linear correlations were then tested with linear regression test to formulate an equation which can predict X-ray measurements from corresponding apex locator measurements.
 Results: Generally, apex locator shows a linear correlation with X-ray in terms of measuring working length of the root (P <0.001). The accuracy of apex locator varies according to the site of the tooth root under investigation, with being most accurate at disto-buccal (Pearson’s r= 0.98, P< 0.001) and least accurate at palatal roots (Pearson’s r=0.57, P=0.084).
 Conclusion: Working length measurement of mesio-buccal and disto-buccal roots using electronic apex locater was precise when compared to radiographic method. While in palatal roots, WL measurements using apex locator were inaccurate when compared to radiographic method.