Electronic apex locator: a useful tool for root canal treatment in the primary dentition.

The purpose of this study was to test the ability of an electronic apex locator, Root ZX to measure the root canal length in primary teeth with partial resorption. Twenty extracted primary molars were embedded in an alginate model imitating in vivo conditions. Root ZX and radiographic measurements were compared in dry and wet environments to the actual tooth length. Root ZX identified the tooth length at the most coronal portion of the resorption. The content of the root canal did not influence the results. No statistical differences were found between electronic, radiographic and actual tooth length measurements, although the radiographic measurements were longer than the electronic ones. It is suggested that Root ZX is a preferable auxiliary device to measure root canal length in the primary dentition.