Tooth cavities provide unique ecological insight into living primates
and fossil humans

Date:
December 13, 2021
Source:
University of Otago
Summary:
Tooth decay is a common and unfortunate problem for many of us,
but two University of Otago studies show it is also an issue for
other primates, as well as our fossil relatives and ancestors.



FULL STORY ========================================================================== Tooth decay is a common and unfortunate problem for many of us, but two University of Otago studies show it is also an issue for other primates,
as well as our fossil relatives and ancestors.


==========================================================================
Dr Ian Towle, the former Sir Thomas Sidey Postdoctoral Fellow in Otago's Faculty of Dentistry, says cavities are often considered to be a modern
disease unique to humans, related to a diet rich in processed sugary
foods. However, he says there is growing evidence tooth decay also occurs
to a certain extent in other animal groups.

"Our new research shows caries also occurs in wild primates in low
frequencies, although this is highly variable among groups and the teeth affected also vary," he says.

"This research helps us understand changes in diet and behaviour in
human evolution; it also provides insight into particular behaviours
in our living primate relatives." For the research, published in the
American Journal of Primatology and South African Journal of Science,Dr
Towle and colleagues analysed more than 8000 extant primate and fossil
human teeth and assessed variation in tooth decay patterns in relation
to diet and behaviour.

They found 3.3 per cent of teeth in living primates had caries, which
is similar to the incidence in fossil humans (ranging from 1 to 4 per
cent of teeth in different species). However, all caries in the fossil
humans samples studied were on back teeth, whereas the vast majority in
living primates were on the front teeth.



==========================================================================
"The fascinating feeding behaviours of animals such as chimpanzees,
using their large front teeth to help suck sugary liquid out of figs, contributes to creating caries patterns rarely seen in humans.

"Indeed, in humans our back teeth are mostly affected by dental decay,
whereas in other primates it's typically the front teeth," Dr Towle says.

Another interesting aspect of this research was that female chimpanzees
had more caries than males (9.3 per cent compared to 1.8 per cent),
with similar sex differences often evident in humans.

The work also revealed how similar decay patterns between captive primates
and humans are, highlighting how primates often don't undertake specific natural behaviours in captivity.

"Caries occurred throughout human evolution and that doesn't seem to
change much for millions of years, with less than 5 per cent of teeth
affected.

However, with the onset of agriculture, this increased rapidly to more
than 20 per cent of teeth having cavities in some samples." This study
is part of a larger body of work Dr Towle and colleagues have undertaken
into the teeth of primates and human ancestors, mentored by Dr Carolina
Loch, of Otago's Faculty of Dentistry.

"I hope this particular part of the research will help the public
understand how living primates have complex and varied feeding behaviours,
yet share this common disease with us.

"Tooth decay has the potential to offer unique ecological insight into
extinct primate groups," Dr Towle says.

========================================================================== Story Source: Materials provided by University_of_Otago. Note: Content
may be edited for style and length.


========================================================================== Journal References:
1. Ian Towle, Joel D. Irish, Kris H. Sabbi, Carolina Loch. Dental
caries in
wild primates: Interproximal cavities on anterior teeth. American
Journal of Primatology, 2021; DOI: 10.1002/ajp.23349
2. Carolina Loch, Christianne Ferne'e, Isabelle De Groote, Joel
D. Irish,
Ian Towle. Dental caries in South African fossil
hominins. South African Journal of Science, 2021; 117 (3/4) DOI:
10.17159/sajs.2021/8705 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/12/211213121841.htm

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