Accuracy of Root Canal Working Length Measurement with Raypex5 Electronic Apex Locator

Objective To study the accuracy of root canal working length measurement with Raypex5 electronic apex locator and its influential factors.Methods 172 patients’196 teeth with 338 root canals,including 124 root canals with pulpitis,84 with necrotic pulp,58 with apical periodontitis and 72 with curing again,were divided into two groups in random.The accuracy of electronic root canal working length measurement group was compared with that of the manual measurement group by 2 test.The influence of clinical types,tooth position and root canal in dry or moisture conditions on the accuracy of root canal working length measurement was analyzed.Results The accuracy of electronic apex locator was 90.53%,while it was 46.15% in manual measurement.The difference was significant (P 0.01).The accuracy in the group of apical periodontitis was significantly lower than those of the other groups (P 0.05).Root canal in dry or moisture conditions had no effect on the accuracy of root canal working length measurement.Conclusion Electronic apex locator is an accurate and convenient device in measurement of root canal working length.While,damage in periodontitis,metals,fillings in root canals,and root hurting all can decrease the accuracy of measurement.