An experimental study of the principle of electronic root canal measurement.

This article presents five experiments. Experiment 1, electronic root canal measurement, was mimicked in vitro. The result was equal to electronic root canal measurement in vivo. In experiment 2, the experiment mentioned above was repeated with the root canal filled with an electrolyte. The result showed that the accuracy was influenced by two factors: moisture content of the root canal and diameter of the apical foramen. Through experiments 3 and 4, the importance of keeping the root canal dry and the caliber of the apical foramen small was stressed. In experiment 5, a glass tubule was used in place of a tooth. When the diameter of the tubule was less than 0.4 mm, the result was similar to that of a tooth. On the basis of these experiments, a purely physical explanation for the principle of the electronic root canal measurement was suggested.