Lack of correlation between microbial penetration method and electro chemical technique for assessment of leakage through the root canal fillings

AIMS: The purpose of this study was to compare microbial penetration method and electrochemical technique for evaluation of the apical seal. MATERIALS AND METHODS: A total of 28 teeth were prepared using the step-back technique to ISO size 40 master apical files. The specimens were randomly divided into an experimental group, two positive and two negative controls. Root canals in the experimental and negative control group were filled with gutta-percha (GP) and sealer, using lateral condensation technique. In the positive control group, canals were filled with GP without any sealer. The external surface of each tooth was coated with two layers of the nail varnish, except for the access opening and the apical foramen. In the negative control group, the teeth were completely covered with nail varnish. The apical seal was recorded with two methods, each successively used on the same teeth: An electrochemical method and a bacterial penetration method. STATISTICAL ANALYSIS USED: The correlation of the electro chemical readings with the results obtained from bacterial micro leakage test was evaluated by Pearson's correlation coefficient. RESULTS: Correlation coefficient of the measurements obtained from the two evaluation methods, was 0.23 (r = 0.23), so the correlation was not statistically significant (P = 0.275). CONCLUSIONS: This study shows that several studies by different methods are necessary before evaluation of the marginal leakage.