An evaluation of the Apex Locator Endocater.

The purpose of this study was to relate the relationship of the apical constriction to the anatomical apex and to determine the ability of the Endocater (Hygenic Corp., Akron, OH), using commercially bonded coated probes to locate the position of the apical constriction, in permanent teeth that were intact and had not been subjected to previous endodontic manipulation. Using local anesthesia and rubber dam isolation, conventional access cavities were prepared at ultra high speed with water coolant in teeth treatment planned for extraction. The Endocater was used to determine the working length. The probes were sealed in place with autopolymerizing composite resin and the teeth extracted. The teeth were sectioned buccolingually, and the position of the probe in relation to the anatomical apex and apical constriction was measured with the use of an ocular microscope. In 17.1% of the canals, the probes bound in the coronal portion of the canals and would not reach the apical portion of the root. In those teeth in which the probes reached the apical portion of the root, the Endocater was able to locate the apical constriction within 0.5 mm in 93.4% of the canals.