For years, scientists have been trying to figure out the origins of tooth pain. A new study has uncovered a surprising link between ancient fish and our modern-day toothaches.
Researchers discovered that the outer layer of teeth is coated in hard enamel, but it’s the inner layer called dentine that feels pain when we bite into something hard or feel cold sensations like ice cream. Dentine carries signals to the nerves, which can cause tooth pain.
The origins of this sensation are believed to date back 465 million years to an early vertebrate fish from the Ordovician period. The study used 3D scans on fossils and found that these ancient fish had a structure called odontodes, which contained dentine. These bumps were sensitive and likely helped the fish sense its environment.
Interestingly, this discovery also reveals a connection between fish and arthropods, like crabs and shrimp, which have similar sensory organs called sensilla. This is an example of evolutionary convergence, where different species develop similar traits on their own.
The study sheds new light on the fossil record, particularly with regards to a Cambrian-era fossil called Anatolepis, which was previously thought to be one of the earliest vertebrates due to its tooth-like bumps. However, further examination revealed that these bumps didn’t contain dentine and were actually similar to the sensory structures found in arthropods.
This research also supports the “outside-in” hypothesis, a theory suggesting that teeth evolved from external sensory structures like odontodes. The study’s findings suggest that this may be true, with the earliest vertebrates having sensitive armor that helped them survive.
Source: https://interestingengineering.com/science/the-surprising-fishy-origins-of-your-toothache