Abstract
The occlusal pressure (kg/mm2), occlusal contact area (mm2) and total occlusal pressures of individual teeth (kg), at the maxillas, were investigated comparatively in Chinese and Japanese children. Adult Japanese were used as controls. "Prescale" was used in the experiment, and the subjects were asked to bite it for five seconds with maximum masticatory pressure. The following results were obtained.
In the experiment with deciduous teeth, the occlusal pressure in the Chinese children was larger for most types of teeth in boys than girls. With the Japanese counterparts, the occlusal pressure differed among the teeth in girls and was lowest with the second deciduous molars. The occlusal contact area was largest with the second deciduous molars in both Chinese and Japanese children, regardless of sex. It was second largest with the central deciduous incisors in the Chinese children. In the Japanese children, the first deciduous molars or central incisors had the second largest occlusal contact area. The total occlusal pressures of the individual teeth in the Chinese children were larger with the first deciduous molars in boys than in girls, while those in the Japanese children were larger with the first deciduous incisors and second deciduous molars in girls than in boys.
When comparing the Chinese and Japanese children, the occlusal pressure, occlusal contact area and total occlusal pressures of the individual teeth were all found larger with most types of teeth in the Chinese boys than in the Japanese boys.
In the experiment with permanent teeth, the occlusal pressure in the Japanese children was larger for all teeth except for the molars in boys than in girls. When comparing the types of teeth in the Chinese children, the second molars had the lowest occlusal pressure. When comparing Chinese and Japanese children, the occlusal pressure was larger with most types of teeth in the Chinese children. No differences between them were found in the occlusal contact area and total occlusal pressures of the individual teeth. However, considering that the Chinese children examined were younger by approximately one year, it was predicted that these values would grow larger in the Chinese children, when they reach the same age as the Japanese children. The occlusal contact area and total occlusal pressures of individual teeth in the children examined were largest with the first molars. In adult Japanese males, these values were largest with the second molars.
