Comparison and reliability of techniques for measuring leakage and marginal penetration.

A new method for assessment of leakage and marginal penetration was developed. The new electrochemical technique employs zero resistance ammetry, and rapid quantitative results can be obtained over a long period of time. The purpose of the study was to compare the reliability of this method of assessment of leakage versus the autoradiographic and dye penetration techniques. The electrochemical data showed that there is a very sharp increase in the penetration during the first 10 days and that maximum leakage occurred on days 11 to 14 of immersion, after which electric flow remained constant. The correlation of the electric readings with the evaluations obtained with the dye penetration and autoradiographic technique was r = 0.46 and r = 0.52, respectively. The correlation was especially correct at the two extreme ends of the electric score ranges.