Studies on Mastication and Biting Forces of Differences from Occlusal Form of Artificial Posterior Teeth of Complete Dentures

In the complete denture prosthodontics, it has been noticed from old times that the occlusal form of artificial teeth influences masticatory efficiency and basic conditions of its forms have been variously investigated. However, at present there is not always a basis on this point.By way'of finding out how the occlusal form of artificial teeth has the influence upon the masticatory forces; the masticating forces and forces in the swallowing period at the upper first molars on the complete denture wearers (6 males) from 50 to 59 in age at differences from occlusal form of artificial teeth are recorded at the same time as the electromyography of masseters and temporalis of left and right side.As the result of these efforts, the following conclusions are obtained.1. The biting forces in upper first molars of the 20 degree cusp teeth are significantly smaller than 30 degree cusp teeth. Especially in the working side of lateral occlusal position, the former predominates over the latter.2. The masticating forces in all foods of 20 degree cusp teeth are larger than 30 degree cusp teeth, but on the forces in the swallowing period the former are smaller.3. As for amount of electoric discharge activity of the masseter and temporalis during masticating each food, 20 degree cusp teeth have a tendency to be larger quantity to 30 degreecusp teeth.4. Through all periods, the masticatory rythm in all foods of 20 degree cusp teethhave a tendency to be larger 30 degree cusp teeth, but in the swallowing period, the former has a tendency of to be smaller.