A comparative evaluation of root canal length measurement techniques in primary teeth.

PURPOSE: The purpose of this 3-staged, in vivo, crossover study was to comparatively evaluate the accuracy of radiograph-based and apex locator-based measurements of working length in primary molars with physiological root resorption.

METHODS

Endodontic access cavity preparations were performed on 13 primary molars in 10 cooperative pediatric dental outpatients who met the selection criteria. Calibrated investigators estimated the root canal length in a total of 30 canals in these 13 primary molars using both apex locators and radiographs. Following determination of working length, the teeth were extracted for in vitro measurement of the actual root canal length. The root canal lengths obtained through these 3 techniques were compared statistically and assessed for the presence of significant differences.

RESULTS

Significant correlation (intraclass correlation=0.99, P<.001) could be detected between working length measurements obtained using both the techniques and direct measurements of root canals. Acceptable measures of working length (+1 mm of actual length) could be obtained in 97% and 93% of canals using apex locators and radiographs, respectively.

CONCLUSION

Apex locators can be considered a viable substitute for radiographs in estimating working length during pulpectomies of primary teeth.