Filling the Holes in Our Ancestor’s History: Studies Find Cavities

Just because today’s society has sweets and sugary drinks to rot our teeth doesn’t mean cavities didn’t exist way back in the day.

Scientists have been finding dental cavities in our ancestor’s teeth — which includes in the mouth of a gorilla-like primate Paranthropus robustus, our ancient 2 million year old cousin from Africa. Two new studies revealed data of teeth from ancient human skeletons and found some unique properties involving tooth decay and cavities.

The first scientific study looked at the bacteria that caused toothaches in our older ancestors. These ancient bacteria are called Streptococcus mutans, who live in the mouth and use the sugars from our food to excrete lactic acid. This lactic acid then wears aware at tooth enamel — the hardest substance in the human body. The wearing down of the enamel is what causes tooth decay and cavities.

Marc Simon from the University at Autonoma in Barcelona, Spain hopes that by studying the ancient bacteria, today’s society will be able to figure out how it grows and how to fight it.

“Hopefully, it will allow us to predict how it will react under certain circumstances, and predicting its behavior might help us to fight it off in the future,” he said.

Simon and his research team extracted the bacteria’s DNA from 10 human skeletons ranging from the Bronze Age (3,200 – 600 BCE) to the 1900’s. The researchers were after just one tiny fragment in the bacteria’s DNA: the part that gives it the ability to causes diseases such as gingivitis and tooth decay.

The results were surprising. The bacteria evolved due to random mutations that did not occur to give it any environmental advantage, though it did become more diverse as our own human population became more unique.

Another study involving cavities involved analyzing plaque particles from the teeth of ancient skeletons. These remains, found in central Sudan, suggest that the purple nut sedge — a plant native to the area — was a crucial part of that society’s diet.

Karen Hardy from the Universitat Autonoma stated that the plant has been found to fight the growth of Streptococcus mutans and the skeletons she and her team have been analyzing have significantly less cavities than other societies during that era.

The Sudanese area in which the team conducted their research is old enough; spanning 7,000 years which range from hunting and gathering eras to agricultural periods. Most scientists believe that cavities increased due to a shift away from hunting and more towards agriculture. Fruits and vegetables are high in carbohydrates and sucrose (sugars) that, when broken down in the mouth, cause these dental caries. Due to an increase in agriculture, Streptococcus mutans also increased and evolved as human diet evolved.

The use of the plant even before the introduction of agriculture suggests that our wise old ancestors may have known the plant carried medicinal properties.

“These small biographical details add to the growing evidence that prehistoric people had a detailed understanding of plants long before the development of agriculture,” said Hardy.

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