Tooth cavities are a common problem and affect a high percentage of the global population; in fact, according to a report by the World Health Organisation, 2.3 billion people suffer from it permanently.
It is a known fact that tooth cavities are linked to and aggravated by the consumption of sugary and ultra-processed foods. However, it is not a problem exclusive to humans and even less to modern humans: it was also suffered by our ancestors and even primates.
In two recent studies from the University of Otago, led by Dr Ian Towle, more than 8.000 fossil human and living primate teeth were analysed to assess the connection between tooth cavities and the feeding and behavioural patterns of these humans and primates.
“Although caries is usually considered a modern disease exclusive to humans, there is increasing evidence that it is also recurrent, at least to some extent, in other animal groups,” explains Dr Towle.
Cavities and wild primates
This new research, published in the American Journal of Primatology and the South African Journal of Science, shows that cavities also occur, although at a lower frequency, in wild primates, and provides information on changes in their diet and behaviour over the years.
“Thanks to the data collected, we can better understand dietary and behavioural changes in human and primate evolution,” points out Towle.
The results showed that 3.3% of living primate teeth had tooth cavities, a similar incidence to that of cavities in fossil human teeth.
There is, however, a variation in the location of these cavities: just as human samples showed cavities in the back teeth, living primates have them in the front teeth, making it clear that feeding habits and patterns are as important as the food chosen, as chimpanzees use their front teeth to suck the sugary liquid from figs, while we use our back teeth for chewing.
With this research, Dr Towle and his team demonstrate how dental cavities have the potential to provide unique ecological insights into living and even extinct primate groups.
The evolution of tooth cavities in humans
“Cavities remained at stable levels for millions of years, with less than 5% of the teeth evaluated were affected, but with the onset of agriculture, this figure increased in the samples studied to 20 %,” says Dr Towle.
It was the emergence of agriculture itself that also brought tooth cavities and its main cause: the Streptococcus mutans bacterium.
In order to adapt to our new diet and become stronger in the face of it, the bacteria underwent major mutations, leading to what we know today as dental cavities, which, as we now know thanks to these studies, shed light on the eating habits of wild animals and those of our ancestors.
