Dental soldering (Part 7). Effects of the space of the soldering gap on adaptability

Abstract

The space of soldering gap was considered as one of the factors that affect the fitness accuracy of the soldering bridge. Three-unit posterior straight bridge was assembled by soldering with the second premolar and molar as abutments and the first molar as a pontic on the right mandible. The soldering gaps were made in three kinds; 50μm, 150μm, 300μm. The threedimensional distortion of both abutments to the pontic was measured, and the displacement and distortion as well as vectors were examined. The results are obtained as follows:1. The direction of displacement showed a similar tendency even when the space of the gapwas changed.2. Both the displacement quantity and S. D. values were smaller when the space was narrower, and a bridge with a wider space showed larger S. D. values.3. As to the distortion, the occlusal surface was bent throughout the bridge and the distortion was observed in the direction of the cervical of the tooth. The S. D. value of the distortion was larger when the space was wider.4. In terms of vectors, both the displacement quantity and the S. D. values were large when the space was 300μm. It is therefore suggested that the displacement quantity is difficult to be controlled when the soldering gap is too wide.