[Observation of marginal leakage with 35SO4 =. 1. Method of testing for marginal leakage]

The purpose of this study was to develop a new observation method of marginal leakage of complete crowns with 35SO4 = labeled compound. The new point of this method was to use 15% gelatine solution, which was very effective to get clear autoradiograms. Once the labeled tracer penetrated marginal gaps, it didn't move away but stayed there. Complete crowns actually cemented to abutment teeth were treated using the new method, so that we could observe marginal condition more clearly than with the conventional method using various dyes or usual simple radioisotope. In this study, we found close relationship between film density of autoradiograms and marginal distance of gaps.