The Association Between Dental Caries And The Emergence Of Agriculture In Prehistoric Thailand From 5000 BP

This thesis explores the prevalence of dental caries and other relevant dental pathologies during the uptake and intensification of agriculture in prehistoric Thailand from c.5000 BP to the Iron Age. It is widely argued that dental caries was not common in human populations until the adoption of agriculture largely resulting from the addition of fermentable carbohydrates from cultivated crops and changes in tooth wear. The assumption of a positive association between dental caries and agriculture has become widely accepted in palaeopathological and archaeological literatures. These generalisations were largely drawn from Old World societies exploiting cereals such as wheat and barley, and especially from the New World, among societies that became heavily dependent upon maize. This thesis will explore whether those generalisations hold true for prehistoric societies in Southeast Asia (specifically from Thailand) who consumed a more mixed agricultural diet of rice, millets, and root crops such as taro. The author explores the study sample by using the standard methods of estimation of age-at-death and sex in mature human skeletons. Additional methods include the use of standard recording and scoring systems to quantify individual carious lesions and related oral pathology for each human dental remain in the sample assemblages. Three hundred sixty-four adult human skeletons (167 males, 197 females) were selected from 13 archaeological series from three different archaeological periods: Neolithic (N=3), Bronze (N=3) and Iron Age (N=7). Including all the permanent dentition gives a total sample size of 6,910 teeth (3,462 male and 3,448 female teeth). The results of this research show no positive correlation between the development of agriculture and the prevalence of dental caries in Thailand’s prehistory from Neolithic to Bronze and Iron Ages. This result also differs from the patterns of dental caries prevalence recorded in archaeological populations in Old and New World samples reviewed in this study. Such difference potentially be associated with different crop types and food processing. Dental remains of prehistoric populations in Thailand from the Neolithic, Bronze and Iron Ages, show no increase in the rates of dental caries over time. This research shows that there is variation in caries frequency but that this is within populations and regions. For example, females tend to have greater prevalence of dental caries than males and that dental caries prevalence seems not age-related, although dental caries is progressively developed over an individual’s lifetime. Apart from a frequency of dental caries, a prevalence of additional relevant pathologies, ante-mortem tooth loss (AMTL), severe attrition, and calculus or dental plaque, were also investigated. A prevalence of AMTL seemed to remain steady at the same level, as relative low rate, from Neolithic to Bronze Age. The result also presented that different rate of AMTL potentially related to different types of food between inland and coastal area.

Regarding severe attrition, it was found that the pattern of pathological frequency was similar to AMTL, since there was no statistical difference of frequency overtime.