IN-VITRO EVALUATION OF THE ACCURACY OF SEVERAL ELECTRONIC APEX LOCATORS

This study describes two tests of the in vitro accuracy of several mod els of electronic canal length measuring devices (ECLMD's) using a gel atin test model and extracted human teeth with fully formed apices. In part 1, four previously untested ECLMD's were used in dry canals afte r access and pulpectomy. File lengths with the file tip just visible a t the foramen were compared to ECLMD lengths. Clinically significant E CLMD measurements of greater than or equal to 0.5 mm than visual lengt h were noted with two ECLMD's 16.6% and 10% of the time. The other two ECLMD's had no measurements >0.5 mm than the visual measurement. The gelatin test model proved highly accurate with 4 of 6 ECLMD's tested t hus far. Part 2 compared the accuracy of a previously tested ECLMD usi ng the gelatin model when taking length measurements with canals both dry and wet with distilled water in them. There was no difference betw een measurements in wet or dry canals. Irrigation with distilled water may be a clinical aid when using resistance ECLMD's.