Your teeth have direct contact with everything you eat (and drink) – so it is hardly surprising that dental disease can directly reflect your diet! Teeth are made of enamel (the outside of the crowns) and dentine (inside the crowns and the tooth roots). Because enamel is very hard, teeth survive burial for hundreds of years very well. Here we discuss two of the most visible dental diseases – caries (cavities) and calculus (mineralised dental plaque).
Dental caries is the scientific name for dental decay. It is associated with a sugary or starchy diet and worsened by poor oral hygiene; it is seen in ancient farming populations, including those of the medieval period.
The following graphs (redrawn after data from Moore and Corbett 1978) compare the amount of sugar eaten per person per year by time period to the rate of caries (percentage of cavities in the populations) from the Anglo-Saxon period until the late 19th century. They clearly show that as sugar consumption increased, so did the rate of caries in the population.
Cavities in teeth are started by the acid produced when mouth bacteria digest carbohydrates (sugars and starches). The acid dissolves and weakens the dental enamel, and a steadily enlarging cavity forms. Most modern peoples eat large quantities of carbohydrates (especially refined sugars), so we are at risk.
Eating lots of sugars, especially when snacking throughout the day, increases the risk of developing caries. During the medieval period refined sugars were very expensive, and we see very low levels of dental caries. During the nineteenth century sugar was produced in industrial quantities and became very cheap and widely available. Around this time we see a sharp increase in the amount of dental caries.
These graphs compare the amount of sugar eaten per person per year by time period to the rate of caries (percentage of cavities in the populations) from the Anglo-Saxon period until the late 19th century. They clearly show that as sugar consumption increased, so did the rate of caries in the population.
In the medieval period, there was no treatment and the cavities would be left to expand, destroying the entire tooth crown and killing the tooth. As the tooth dies, infection spreads into the nerve of the tooth, producing a desperately painful abscess. If the tooth is not taken out, a hole will eventually form in the jawbone (a granuloma). If this became infected, an abscess would form – once the abscess has pushed a hole through the bone it would become less painful, but could ooze pus for years.
There is a large carious lesion (cavity) in the first molar on the right side (on the left in this photo), with another carious lesion in the smaller premolar, next to it. A very small cavity can been seen on the opposite first molar.
This carious lesion (cavity) is very large in this image. An abscess is present in the mandible (lower jaw) – the rounded edges to the hole suggest it was oozing pus for a long time before death.