大田・津雲・吉胡貝塚出土人骨歯牙の比較 : 齲蝕と歯牙疾患の検討を中心として

This paper was written as a part of research project on dental diseases during the Jōmon period. The “Kiyono Collection” contains vast numbers of ancient skeletons found in shell mounds from the Jōmon period. Many of them were excavated in the Taishō period (1912-26) and the early Shōwa period (1926-89) by Dr. Kiyono and are in good condition. The remains have since been stored at the Department of Anthropology, Faculty of Science at Kyōto University. As such, I had the opportunity to conduct a comparative analysis on dental diseases (especially dental caries and periodontal disease) based on the skeletons found at the shell mound sites.
Material from a total of three shell mounds sites was investigated, including 34 samples from the Ōta site, 51 samples from the Tsukumo site, and 82 samples from the Yoshigo site. These were selected from a total of 216 samples from seven shell mounds due to the good condition of the teeth. The analysis was conducted following methods outlined in a former paper on the Kofun and Kamakura Period (Nagai 2017). The method used to examine caries involved the clinical classifications C1, C2, C3, and C4. For periodontal diseases, the absorption of alveolar bone was measured according to distance via the cement enamel junction-alveolar crest (CEJ-AC), while horizontal and vertical presence was measured using a vernier caliper. The specific items of examination were dental caries, periodontal diseases, attrition, and dental diseases.
Regarding dental caries, the lowest rate of occurrence was observed at the Ōta site from the Middle Jōmon period, followed by the Tsukumo and Yoshigo sites, while the highest rate was found at the Yoshigo site from the Late Jōmon period. Samples from all of three sites were observed for tendencies related to oral contamination type caries. In summary, different types of caries were observed at all three sites. For instance, the discrepancy type was observed at Tsukumo, while rampant caries and large concentrations were observed from one specific person at Yoshigo. Overall results indicate that missing teeth were the result of periodontal diseases at Tsukumo, but were caused by caries at Yoshigo. In accordance with previous studies, the rate of caries tended to increase from the Middle to the Late Jōmon period.