Development of electrical method for diagnosis of microleakage of restrorations by three dimensional analysis

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A new objective electrical method for diagnosis of microleakage along restoratives that was used the change of conductance across the margin was designed by us. The aim of this study was for development an objective clinical microleakage diagnosis. First, a quantitative three-dimensional method for evaluation of the contraction gap in restoratives was designed. Coronal cavities were prepared in human extracted molars and were filled with a composite. After that, specimens were reduced every 100μm in a direction perpendicular to the cavity floors. The images of the surfaces of reducing the sections were taken with CCD camera, three-dimensional images of these microleakages were made and the three-dimensional actual amounts of microleakage were evaluated. From this experiment, the measurement condition and concrete method of the quantitative three-dimensional evaluation method of contraction gap was established. Second, the results by our electrical method were compared with those by thr … More ee-dimensional method in in vitro situation. Concretely, coronal cavities were prepared in human extracted molars and were filled with a composite. The changes of conductance across the margin of these restoratives before cavity preparation, after polishing and after load cycling until 10000 times (400g load) for evaluation of microleakage. In addition, after dye penetration, the three-dimensional images of these microleakage were made and the three-dimensional actual amounts of microleakage were evaluated. From the results of this experiment, the results by conductance measurements were correlated with the actual amounts of microleakage by three-dimensional method. After this experiment, the electrical evaluation of microleakage with some dogs was tried, but much noise was generated as the low voltage of our LCR meter. Therefore, the in vivo experiment is future theme. However, the quantitative three-dimensional evaluate method of contraction gap was developed and the valuable of the electrical method for diagnosis of microleakage was proved by the three-dimensional method. Less