National: Brushing up on the Bronze Age as 4,000-year-old tooth found

Teeth, dating back as far as the Bronze Age, have been found and recovered from one Irish cave.

A molar thought to date back 4,000 years has been discovered in a limestone cave in 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 cave at Killuragh, Co Limerick, 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.”