Human ancestors had the same dental problems as us – even without fizzy drinks and sweets

March 2, 2018 by Ian Towle, The Conversation
Human ancestors had the same dental problems as us – even without fizzy drinks and sweets
Australopithecus africanus teeth with lesions. Credit: Ian Towle, Author provided

Dental erosion is one of the most common tooth problems in the world today. Fizzy drinks, fruit juice, wine, and other acidic food and drink are usually to blame, although perhaps surprisingly the way we clean our teeth also plays a role. This all makes it sound like a rather modern issue. But research suggests actually humans have been suffering dental erosion for millions of years.

My colleagues and I have discovered dental lesions remarkably similar to those caused by modern erosion on two 2.5m year-old front from one of our extinct ancestors. This adds to the evidence that prehistoric humans and their predecessors suffered surprisingly similar dental problems to ourselves, despite our very different diets.

Dental erosion can affect all dental tissue and typically leaves shallow, shiny, lesions in the enamel and root surface. If you brush your teeth too vigorously you can weaken dental tissue, which over time allows acidic foods and drinks to create deep holes known as non-carious cervical lesions (NCCLs).

We found such lesions on the fossilised teeth from a human ancestor species Australopithecus africanus. Given the lesions' size and position, this individual would likely have had toothache or sensitivity. So why did this prehistoric hominin have tooth problems that look indistinguishable from that caused by drinking large volumes of fizzy drinks today?

The answer may come back to another unlikely parallel. Erosive wear today is often also associated with aggressive tooth brushing. Australopithecus africanus probably experienced similar dental abrasion from eating tough and fibrous foods. For lesions to form, they would still have needed a diet high in acidic foods. Instead of fizzy drinks, this probably came in the form of citrus fruits and acidic vegetables. For example, tubers (potatoes and the like) are tough to eat and some can be surprisingly acidic, so they could have been a cause of the lesions.

Carious lesions on the mandibular right second premolar and first molar. Homo naledi (UW 101-001). Credit: Ian Towle

Dental erosion is extremely rare in the fossil record, although this might be because researchers haven't thought to look for evidence of it until now. But another type of problem, carious lesions or cavities, has been found more often in fossilised teeth.

Cavities are the most common cause of toothache today and are caused by consuming starchy or sugary food and drink including grains. They are often considered a relatively modern problem linked to the fact that the invention of farming introduced large amounts of carbohydrates, and more recently refined sugar, to our diets.

But recent research suggests this is not the case. In fact, cavities have now been found in tooth fossils from nearly every prehistoric hominin species studied. They were probably caused by eating certain fruits and vegetation as well as honey. These lesions were often severe, as in the case of cavities found on the teeth of the newly discovered species, Homo naledi. In fact, these cavities were so deep they probably took years to form and would almost certainly have caused serious toothache.

Example of a notch from a clay pipe (17th century set of teeth). Credit: Chip Clark, Smithsonian Institute
Dental abrasion

Another striking type of dental wear is also more common in the fossil record, and again we can guess how and why it was created by looking at the teeth of people alive today. This process, called dental abrasion, is caused by repeatedly rubbing or holding a hard item against a tooth. It could come from biting your nails, smoking a pipe or holding a sewing needle between your teeth. These activities usually take years to form noticeable notches and grooves, so when we find such holes in they offer fascinating insights into behaviour and culture.

The best examples of this type of prehistoric dental wear are "toothpick grooves", thought to be caused by repeatedly placing an object in the mouth, usually in the gaps between the back teeth. The presence of microscopic scratches around these grooves suggests they are examples of prehistoric dental hygiene, where the individual has used stick or other implements used to dislodge food. Some of these grooves are found on the same teeth as cavities and other dental problems, suggesting they may also be evidence of people trying to relieve their toothache.

These lesions have been found in a variety of hominin species, including prehistoric humans and Neanderthals, but only in the species most closely related to us, not our older ancestors. This might mean this tooth wear is the result of more complex behaviour from species with larger brains. But more likely it's a consequence of different diets and cultural habits.

What we do know for sure is that the complex and severe we often associate with a modern diet of processed foods and refined sugars actually existed far back into our ancestry, although less frequently. Further research will likely show that were more common than previously thought in our ancestors, and ultimately will provide more information into the diet and cultural practices of our distant fossil relatives.

Explore further: Sipping hot fruit teas can lead to tooth erosion

Related Stories

Sipping hot fruit teas can lead to tooth erosion

February 26, 2018
An investigation by scientists at King's College London into why some people suffer tooth erosion while others don't has found that it's not just what they eat and drink, but how they eat and drink, that increases their chances ...

Do girls have stronger teeth than boys?

January 10, 2018
What if you hardly ever consume soft drinks or eat anything acidic, but still have dental erosion on your teeth? Do genes play a role? And does it matter if you are a boy or a girl?

Health of primary teeth an early predictor of adult teeth

January 8, 2018
Do children really need their baby teeth? Many believe that primary teeth aren't all that important. After all, they typically fall out by age 12, and new, adult teeth take their place.

Sugar-free drinks and lollies are bad news for teeth say dentists

November 26, 2015
Scientists at the University of Melbourne's Oral Health Cooperative Research Centre have warned about the damage sugar-free drinks can do to tooth enamel.

Recommended for you

Oral cancer prognostic signature identified

December 5, 2018
Researchers in Brazil have identified a correlation between oral cancer progression and the abundance of certain proteins present in tumor tissue and saliva. The discovery offers a parameter for predicting progression of ...

Much-needed new antibiotic shows great promise for treating gum disease

October 23, 2018
A new antibiotic being developed at the University of Virginia School of Medicine appears ideal for battling periodontal disease, the leading cause of tooth loss in adults, according to dental researchers at Virginia Commonwealth ...

Researchers identify immune culprits linked to inflammation and bone loss in gum disease

October 17, 2018
An unhealthy population of microbes in the mouth triggers specialized immune cells that inflame and destroy tissues, leading to the type of bone loss associated with a severe form of gum disease, according to a new study ...

Periodontal disease bacteria may kick-start Alzheimer's

October 4, 2018
Long-term exposure to periodontal disease bacteria causes inflammation and degeneration of brain neurons in mice that is similar to the effects of Alzheimer's disease in humans, according to a new study from researchers at ...

Dental research shows that smoking weakens immune systems

September 26, 2018
As if lung cancer, emphysema and heart disease weren't enough, there's more bad news for cigarette smokers.

Regrowing dental tissue with stem cells from baby teeth

September 11, 2018
Sometimes kids trip and fall, and their teeth take the hit. Nearly half of children suffer some injury to a tooth during childhood. When that trauma affects an immature permanent tooth, it can hinder blood supply and root ...

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

katesisco
2 / 5 (1) Mar 03, 2018
http://content.ti...,00.html
More likely site specific.
katesisco
1 / 5 (1) Mar 03, 2018
There is also strong evidence that there are individuals--noted by embalmers and morticians---that DO NOT HAVE DAMAGED TEETH AT DEATH. This is a genetic condition passed down. As noted by one study of related lineage to a king, it is possible this is solely due to one individual.
Science has discovered that lung alveoli can be created. It is stem cell P63+/Krt5T. There was evidence of HIV resistant individuals also.
Whether we are all born with superior health conditions and they are ' turned off ' by our environment or whether these pro health conditions are selectively included in our genetic structure, it is evident that this is the route to follow for good health. Is the gut bacteria good or bad?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.