No signs of tooth decay in half of Swedish Viking population

Analysis of thousands of Viking teeth from a late Swedish Viking population reveals roughly half of the population were free from decay.

The other half (49%) suffered from some form of tooth decay, and about 4% had an infection.

Researchers from the University of Gothenburg in Sweden analysed 3292 Viking teeth from an excavation of the oldest known ruins of a Christian stone church and cemetery located behind Varnhem Abbey in Skara, Sweden, publishing their findings in PLOS ONE.

Author Carolina Bertilsson tells Cosmos: “Since teeth preserve very well postmortem, due to high mineral contents, they are a unique source of information. Dental caries is a disease that is strongly linked to diet, so it can give clues regarding dietary habits and contents.

“It is also – especially for me as a dentist – a very relatable condition,” she says. “Since the disease itself is the same now as then. We know how tooth ache feels, or when something gets stuck between the teeth. When finding signs of this in a Viking time individual, it really bridges over the time between now and then.”

Analysing the jaws and teeth of 171 individuals from the 10^th – 12^th Century provides a “unique understanding of life and death in this early Christian Viking community and indicated that it was common to suffer from dental caries, tooth loss, infections of dental origin and tooth pain,” the paper says.

“It is probable that no oral hygiene measures other than tooth picking were implemented,” the authors write. Although the strategy appears to have had some success: “notably, at the sites with abrasion marks from tooth picking, no carious lesions were found”.

Along with tooth picking, there was evidence of tooth filing in one male.

The researchers say the reason why Vikings filed their teeth remains unknown, but is thought to been a marker of identity.

Analysis included clinical examinations of the teeth by a dentist using a dental probe under strong light. Researchers also randomly selected 18 individuals for radiographic examination to confirm their findings.

The remains include 133 individuals with permanent teeth (likely aged over 12 years old). In this group 62% had signs of tooth decay and 4% had signs of infection. About a quarter (23%) of teeth had been lost. 

Among the adult population, the analysis suggests the average age of death was 35, ranging between 14 to over 50. 

None of the 38 individuals aged under 12 years old had signs of decay.

The paper says like most Swedish Vikings, the population of Varnhem lived in farm-based communities. Their diet included meats like beef, port and mutton, fish, dairy, bread, porridge and vegetables inclyding cabbage, turnips, leeks, mushrooms and hazelnuts.

They likely drank beer, and occasionally milk and mead.

Dental analysis can offer insights into the everyday life of Vikings, the researchers say.

“The unique and extensive collection of remains from the Varnhem settlement can provide a comprehensive idea of oral health in Sweden during the Viking Age.”

Bertilsson says prevalence of caries was similar to other European populations from the same time period.

Interestingly, the rates of tooth decay in contemporary societies appear broadly similar, although the causes might differ. The World Health Organisation says almost half of the world’s population is affected by dental caries, making it the most prevalent of all health conditions. Today, rising sugar consumption is the main cause of dental caries.

Bertilsson says it is hard to make direct comparisons: “since in prehistorical populations, we see a cumulative effect of caries which then leads to teeth being lost”.

“However, in contemporary populations, we have treatments and preventive measures such as fluoride toothpaste which changes the pattern of the caries disease. We also have a lot of highly processed carbohydrates and sugars in our diet which increases the risk of caries,” she says.