Brushing up on the Bronze Age: 4,000-year-old tooth found in Limerick

Faye Dorgan, 27 Mar

Teeth, dating back as far as the Bronze Age, have been found and

recovered from a cave in Limerick.

A molar thought to date back 4,000 years has been discovered in the

limestone cave Killuragh, Cappamore, Co Limerick.

Considered somewhat of a breakthrough in the scientific world, the

discovery points toward early evidence of bacteria that cause tooth

decay and gum disease.

Trapped within the dental remains that are thought to belong to an

adult man from the Bronze Age era was an "unprecedented quantity" of

the DNA of streptococcus mutans, a type of bacteria in the human mouth

responsible for cavities.

The research team, who also uncovered other types of microbes

associated with gum disease, said the discovery helps shed insight into

how the human diet evolved across centuries - particularly in relation

to sugar consumption.

Branded an “extremely rare find”, the researchers said that the cool,

dry and alkaline conditions of the Killuragh cave (pictured below) may

have helped in the “exceptional preservation” of the DNA.

Assistant professor at Trinity College Dublin, Lara Cassidy said: "We

were very surprised to see such a large abundance of mutans in this

4,000-year-old tooth.

“It is a remarkably rare find and suggests this man was at high risk of

developing cavities right before his death.”

Archaeologists previously observed a rise in dental cavities in

skeletal remains when humans began to adopt cereal agriculture, but

tooth decay became much more common in the Early Modern period,

beginning about 1500 AD.

Speaking on RTÉ's Morning Ireland, Professor Cassidy said that

prehistoric people would have had ways of cleaning their teeth “just

not as advanced as ours”.

“They would have used toothpicks,” she said.

“Actually, there's evidence for a million-year-old toothpicks, so we've

been picking our teeth for a long time and they have used twigs as

brushes and stuff.

“The thing about the Bronze Age is it was agricultural, so cereal would

have been a big part of the diet, so you'd have had a carb-rich diet

and that can promote dental decay.”