Windows into the past: recent scientific techniques in dental analysis.

Teeth are the hardest and most chemically stable tissues in the body, are well-preserved in archaeological remains and, being resistant to decomposition in the soil, survive long after their supporting structures have deteriorated. It has long been recognised that visual and radiographic examination of teeth can provide considerable information relating to the lifestyle of an individual. This paper examines the latest scientific approaches that have become available to investigate recent and ancient teeth. These techniques include DNA analysis, which can be used to determine the sex of an individual, indicate familial relationships, study population movements, provide phylogenetic information and identify the presence of disease pathogens. A stable isotopic approach can shed light on aspects of diet and mobility and even research climate change. Proteomic analysis of ancient dental calculus can reveal specific information about individual diets. Synchrotron microcomputed tomography is a non-invasive technique which can be used to visualise physiological impactful events, such as parturition, menopause and diseases in cementum microstructure - these being displayed as aberrant growth lines.

Dental calculus - oral health, forensic studies and archaeology: a review.

Dental calculus is recognised as a secondary aetiological factor in periodontal disease, and being a prominent plaque retentive factor, it is routinely removed by the dental team to maintain oral health. Conversely, dental calculus can potentially be useful in forensic studies by supplying data that may be helpful in the identification of human remains and assist in determining the cause of death. During the last few decades, dental calculus has been increasingly recognised as an informative tool to understand ancient diet and health. As an archaeological deposit, it may contain non-dietary debris which permits the exploration of human behaviour and activities. While optical and scanning electron microscopy were the original analytical methods utilised to study microparticles entrapped within the calcified matrix, more recently, molecular approaches, including ancient DNA (aDNA) and protein analyses, have been applied. Oral bacteria, a major component of calculus, is the primary target of these aDNA studies. Such analyses can detect changes in the oral microbiota, including those that have reflected the shift from agriculture to industrialisation, as well as identifying markers for various systemic diseases.

The Two Brothers: an enlightening study of ancient Egyptian teeth.

The 'Two Brothers', two 4,000-year-old Egyptian mummies, were discovered buried alongside each other in an ancient Egyptian tomb in 1907, and were later relocated to the Manchester Museum. The hieroglyphic inscriptions on the coffins indicate that the mummies, Nakht-Ankh and Khnum-Nakht, were brothers but when the mummies were unwrapped and investigated in 1908, the skeletal morphologies were found to be quite different, suggesting an absence of family relationship. In 2017, their teeth were re-examined and, similar to most ancient Egyptian teeth, they display evidence of excessive tooth wear but there is little indication of carious lesions. Khnum-Nakht presents the rare developmental disorder of fusion of the left maxillary incisor and gemination of the right incisor, probably the earliest recorded instance of this irregularity. Analysis of the DNA from their molar teeth has been able to shed some light on the longstanding question of the kinship of the Two Brothers.

Unlocking the past: The role of dental analysis in archaeology.

What can the study of ancient teeth tell us about the life style and dietary habits of our ancestors? Dental palaeopathology is particularly important as it can provide direct evidence of the type of diet an individual consumed during life. An analysis of the angle of tooth wear evident on the crown of the tooth can help to distinguish between early hunter-gatherers and later agriculturists, whilst microwear features on the occlusal surface can help to discern subtle dietary shifts. The distributions of stable isotopes in food webs make it possible to use them to reconstruct ancient diets as well as tracing the geographic origins and migrations of peoples. Plant microfossils have been isolated from calculus which can be identified using light microscopy. Teeth are particularly useful in ancient DNA studies due to the excellent preservation of biomaterials within the enamel shell of the tooth.