Studies on Stress Distribution under Simulated Muscles on Dry Skull Utilizing Thermoelastic Stress Imaging Method

Part II. Influence of the Difference of the Size of Vector when the Muscles Activity of Mastication is Tested in Vectors

Abstract

Under two conditions considering the direction and activities of the mastication muscle, we investigated the strain distribution on the loading or unloading side of mandible in cases where the loads were applied to the first premolar and first molar.
1. At the loading points, the amount of compressive strain directly below the first premolar tooth was larger than that directly below the first molar tooth.
2. In the external surface ranging from the ramus mandible to linear oblique mandible, the tensil strain was recognized, and the amount loaded at the first premolar tooth was found to be larger than at the first molar.
3. In the external surface of mandibular notch, the amount of strain was, when a hard force loading was applied, larger on the loaded side, as well as it was larger when a force loading was applied to the first premolar than when applied to the first molar.