Study on arrising factors of TM disorders and food habits -Survey on the Central American Indian, whose origin are the same as Japanese-

本研究由两个目的组成：一个是关于TMS发病率的流行病学研究，另一个是利用干燥的颅骨标本来研究牙齿磨损与髁突形态变化之间的关系。为了进行调查，我们选择了一个主要由中美洲洪都拉斯和危地马拉的土著居民组成的人群，他们与日本人有着相同的根基，但他们的生活环境，尤其是饮食习惯，与日本人不同。结果：TMS的发病率从低到高依次为居住在山区的洪都拉斯印第安人[31.7%(20/63)]、危地马拉印第安人[42.1%(43/02)]、加勒比海科苏岛的洪都拉斯印第安人[46.8%(74/58)]和特古西加尔巴公民，洪都拉斯首都[50.0%(26/52)]。磨耗Broca(B)用于评估磨耗程度，所有TMS患者均为1级或2级。在牙齿磨耗与下颌突形态变化的关系方面，B1-B3轻度磨耗组为凸型，B2-B4组为平坦型。讨论：本研究结果提示TMS患者的适应性较差，表现为轻度磨损和下颌骨髁状突轻微改建。

The present study consists of two objectives: an epidemiological study of the incidence of temporomandibular symptoms(TMS) and an investigation to clarify the relationship between the dental attrition and morphological change of condyle using dried cranial bone samples.In order to conduct the survey, we selected a population consisting mainly of the native inhabitants of Honduras and Guatemala in Central America, who have the same radical roots as the Japanese and whose living environment, especially eating habits, are different from those of Japanese. As for the latter investigation, we collected data on native indians in Central America.Results: The ranking of incidence of TMS, from lowest to highest, was a Honduran native indians, living in the mountain[31.7%(20/63)], Guatemalan native indian[42.1% (43/02)], a Honduran native Indian on the Coasu of the Caribbean Sea[46.8%(74/58)] and the citizens of Tegucigalpa, the capital of Honduras[50.0%(26/52)].Attrition Broca(B)was used to evalvate the degree to attrition and all patients with TMS were classified as either class 1 or class 2.Regarding the relationship between dental attrition and the morphological change of mandibular condyle, the B1-B3 mild attrition group was classified as convex type, while the B2-B4 group was classified as fiat type. The present study demonstrated that the number of cases of fiat type increased as attrition progressed from a mild to severe degree.Discussion: The results obtained in this study suggested that the patients with TMS were in a state of poor adaptability character; zed by mild attrition and slight remodeling of the mandibular condyle.