Effectiveness of an electronic apex locator used after preflaring of cervical and middle third

Resumo

The electronic method has been studied and improved
aiming to add precision, speed and reliability of the measurement
technique to determine the exact location of the working length.
Currently, the root canal preparation recommends prior to determine
the tooth length and consequent perform instrumentation of the
apical portion, a previous preflaring of the cervical and middle
thirds in various techniques. This procedure may provide a reduction
in system impedance, leading to read errors by the apex locators.
Objective: Investigate the influence of preflaring of the cervical and
middle thirds on the accuracy of measuring the working length by
apex locators. Material and methods: Twenty-five mesial roots of
molars were used and had their crowns cut at the cemento-enamel
junction. The actual measure of each root canal was performed
and then the samples were embedded into a mixture of alginate,
used as a conducting medium, where electronic measurements
were taken with apex locator before and after preflaring of the
canals with Gates-Glidden drills in descending order (#4, #3, #2).
Measurements obtained by electronic method were then compared
with the actual measurement of the root canal. The results were
tabulated and submitted to the Student t test Results: The results show that there was no statistical significance (p<0.05) between the
readings before and after preflaring. Readings closer to the foraminal
ending occurred in the group after preflaring with Gates Glidden.
Conclusion: It was concluded that preflaring with Gates Glidden
drills were not able to influence significantly the accuracy of apex
locator in determining the exact working length.