A sample of skeletons excavated from an undisturbed prehistoric (4000-3500 years BP) burial site in Thailand included a high proportion of individuals with anterior teeth missing in distinctive, mostly symmetrical, patterns. The patterns, types and numbers of teeth missing have been compared between males and females, with age at death, with depth of burial and among spatially distinct groups within the cemetery. The patterns of missing teeth changed over time. In early burials, lateral maxillary incisors were most commonly missing. Two-thirds of the adults had missing teeth. There were no significant differences between the sexes or with age. In later burials, central maxillary incisors and mandibular incisors were most commonly missing. All adults and some children as young as 11 years had missing teeth. There were no significant changes with age but females had more missing teeth than males.
Loss as a result of extreme wear inflicted through the use of teeth as tools, congenital absence and ritual ablation are discussed as explanations for the absence of the teeth. The evidence suggests that ritual ablation is the most likely explanation, although the loss of mandibular incisors in some early burials may be as a result of industrial use of the teeth. The ablation of maxillary lateral incisors, found in the early burials, has been recorded at another prehistoric site in the west of Thailand and at sites in southern China.