Until just over 200 years ago, the normal human bite was edge-to-edge. That is, when the molars were clenched together, the cutting edges of the upper and lower incisors met each other rather than overlapping as is now considered normal. The change took place in Europe following the adoption of the dinner fork and the changes in eating habits it indicated late in the 18th century. Because of the hiatus in Old World contacts caused by the American Revolution, that change did not begin to take place until the third decade of the 19th century in America. A similar change should have occurred in Asia following the change in food preparation methods that allowed chopsticks, kwai-zi in China and hashi in Japan, to be used as everyday eating utensils. Preliminary work in China indicates that the modern overbite occurred in upper class Chinese in the Song Dynasty. Song cultural influences had a profound effect on life in Japan, and the purpose of this project is to test whether the adoption of Chinese food preparation and eating habits exemplified by the use of chopsticks was accompanied by a change from the edge-to-edge bite of the first Japanese farmers and their descendants in Yamato Japan which immediately preceded the first major influences from China. These investigations will help clarify the relationships between diet, eating behavior, food preparation technology and normal occlusion of the dentition.
