An Apple a Day Keeps More Than the Dentist Away

Dental health is important. Not just because we have high standards of oral health in the USA, or because of their importance in mastication. Dental health has a major effect on the overall health of an individual. A new study from the American Journal of Physical Anthropology assesses the association of dental health with other pathology on the skeleton. A number of modern studies have correlated dental diseases with other infections and pathologies, finding that individuals with poor oral health have a higher risk of mortality. However, there has been little correlation done of past societies to see whether the same processes were effecting them. DeWitte and Bekvalac (2011) analyze the correlation of periodontal disease with periosteal lesions in a Late Medieval cemetery in London, England.  In a prior study they found that there was indeed a relationship between dental health and mortality. This study focuses on a specific correlation in order to better understand specific relationship between oral health and susceptibility.

From UCL, Periodontal Disease

Periodontal disease is an infection that causes inflammation and destruction of the gingiva (gum tissue) as well as the periodontal ligaments, root, and alveolar bone. In skeletal remains it is primarily identified by the loss of alveolar bone in the mandible and maxilla, instead of smooth hard bone, the underlying trabecular bone is revealed creating a porous look. It can also cause the bone to recede from the teeth, creating a wider gap between them, often loosening teeth. This diagnosis can be problematic because the skeletal changes associated with periodontal disease only occur in more extreme cases, therefore false negative is possible.

Museum of London, Periosteal Lesion

Periosteal lesions are similar to periodontal disease in that it is caused by inflammation or infection. Periostitis appears as new bone growth on the periosteum, often appearing as raised areas of woven bone. Periostitis is used by bioarchaeologists as a sign of non-specific stress because they are associated with a wide range of diseases, infections and trauma. By analyzing periostitis against periodontal disease, DeWitte and Bekvalac (2011) argue that they can assess a relationship between dental health and extra-oral health.

The study used a sample of 265 individuals from the St. mary graces cemetery. it includes individuals from all age groups and sexes. Periodontal disease was assessed by the presence of porosity in the alveolar bone, as well as the distance between the cementoenamel junction and alveolar crest (the distance between the gum and teeth which often widens with poor dental health). Periosteal lesions were measured on the tibia because it is most likely to be affected. They were scored present or absent on both right and left tibiae. Stature based on adult femur length and the presence of enamel hypoplasia was also assessed in order to determine the role of childhood health. Short stature and the presence of enamel hypoplasia are indicators of stress during childhood.

Results showed a clear correlation between periodontal disease and periosteal lesions. Of sub-adults, 26 of 35 have neither pathology and 0 have both. In adults 19 of 69 have neither, and 8 have both. In old adults 14 of 65 have neither and 15 have both. Periodontal disease is much more prevalent in older groups. Also, periosteal lesions are positively correlated with periodontal disease, and the association is not explained by age. There was no indication that the correlation could be linked to a predisposition caused by childhood stress, as stature and enamel hyoplasia did not correlate with the two pathologies.

DeWitte and Bekvalac (2011) argue that the relationship between periodontal disease and periosteal lesions can be explained by spread of infection from one area to the other, can be a reflection of a compromised immune system, or can be caused by the body’s reaction to infection creating antigens to remove it. They propose that an underlying weak immune system is likely to be the cause due to the overall health and poor urban environment. The presence of enamel hypoplasia in a third of the sample shows that life in general was difficult from birth.

The only downside of this article is that it fails to assess potentially the most interesting part, which is the relationship between the individuals and their context. If indeed the correlation between the pathologies is related to the environment and overall life, the investigation should discuss further why this is possible. It is common knowledge that Medieval London was not a ‘healthy’ place to live, but its important that we challenge common knowledge or back it up with evidence. While the scope of this article is limited to the skeletal remains, it would be interesting to see this placed into the wider body of knowledge of the time period and area. If you are interested in learning about this, I suggest reading Roberts and Manchester’s History of Health and Disease in Britain.

Works Cited

ResearchBlogging.orgDewitte SN, & Bekvalac J (2011). The association between periodontal disease and periosteal lesions in the St. Mary Graces cemetery, London, England A.D. 1350-1538. American journal of physical anthropology, 146 (4), 609-18 PMID: 21997205

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