Scientists have found a bacterium that causes tooth decay on a 4,000-year-old tooth

Scientists have found a bacterium that causes tooth decay on a 4,000-year-old tooth

Scientists have found a bacterium that causes tooth decay on a 4,000-year-old tooth

Lara Cassidy

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On the teeth of a person who lived about 4,000 years ago, scientists found a large number of bacteria that cause caries and inflammation of the gums. This finding may help to understand what changes in human nutrition have led to the prevalence of this disease in our time.

This is stated in the study, published in the scientific journal Molecular Biology and Evolution, informs CNN.

The bacteria-infected teeth were found during excavations in 1993 and 1996 in a limestone cave in County Limerick, Ireland. They were among human remains.

During the analysis, the scientists found that the teeth were original. They belonged to a person who lived in 2280-2140 BC – in the Bronze Age.

One tooth had a large amount of Streptococcus mutans, the oral cavity bacteria that causes tooth decay. However, there were no signs of the disease on him – they did not have time to appear.

According to study co-author Lara Cassidy, this bacterium is rarely found in ancient genomes. Probably, due to its acid-forming nature, which causes tooth decay and DNA degradation, it is poorly preserved.

Another possible reason for the unpopularity of S. mutans in ancient times could be changes in people’s diet – in the past, people consumed less refined sugar and processed foods.

According to Cassidy, with the development of agriculture about 10,000 years ago, there were significant changes in nutrition. At the same time, the popularization of sugar has been observed for the last several hundred years.

Analysis of bacteria on Bronze Age teeth revealed that the evolutionary tree of S. mutans is more complex than previously thought. Scientists have discovered that its ability to damage teeth has evolved along with changes in human nutrition.

As Cassidy noted, this discovery may help explain why tooth decay has become such a common oral problem in our time.

Why the bacteria on the tooth were so well preserved is still unclear. According to the scientist, the cool and dry conditions of the cave contributed to this.

Archaeologists have previously found S. mutans in other ancient teeth, but at the time they were observed in small amounts.

Two other teeth found contained DNA from Tannerella forsythia, a bacteria that causes gum disease. Researchers have identified two different strains of it, although only one of them is usually found.

This means that ancient microbiomes were much more diverse than modern ones. As scientists have noted, the loss of biodiversity can have a negative impact on human health.

A few more teeth found in the cave had signs of caries. However, it is not known whether they belonged to the same person.

We will remind, scientists discovered a unique property of the human brain, having examined almost 4,500 samples, which are about 12,000 years old.

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