- Many people have teeth that are sensitive to cold foods and drinks
- Why this is the case was unknown, until now
- A new study shows how a specific sensor found in teeth causes hypersensitivity to cold
You bite into your favourite popsicle, and waves of chilly pain shoot through your teeth right into your brain – a scene that is all too familiar to many of us.
If eating ice-cream or drinking cold beverages causes you to experience this sensation, it means you suffer from cold-sensitive teeth. Previously, the mechanisms behind this were not properly understood, but a recent study revealed why people have this sensitivity, as well as how it can be prevented.
What causes teeth to sense cold?
While teeth can hurt for a range of different reasons – such as cavities and gum erosion – the researchers of the present study found that odontoblasts (cells found beneath tooth enamel) play a key role in the specific type of pain experienced by individuals with cold sensitivity.
In mice and humans, odontoblasts contain proteins sensitive to cold that can detect a decrease in temperature by using an ion channel known as TRPC5. In a previous study, the researchers found that TRPC5 was very sensitive to cold, but they could not pinpoint where in the body this cold-sensing ability operated.
“[At that point] we hit a dead end,” said Katharina Zimmermann, who led the study. It was only at a later stage, while having lunch, that the team thought about teeth as a body part that also sense cold.
Mice as study subjects
The team conducted a study on mice. Some mice were normal, while others lacked TRPC5 or had their teeth dipped in a special solution.
The researchers observed the neural activity of the mice while applying an ice-cold solution to their teeth. In the normal mice, neural activity was sparked after the cold solution touched their teeth, but the opposite was true for the mice lacking TRPC5 or those who had their teeth dipped in a solution to block the ion channel.
“We found that odontoblasts, which support the shape of the tooth, are also responsible for sensing cold,” said one of the senior authors of the paper, Jochen Lennerz.
“We now have definitive proof that the temperature sensor TRCP5 transmits cold via the odontoblasts and triggers nerves to fire, creating pain and cold hypersensitivity. This cold sensitivity may be the body's way to protect a damaged tooth from additional injury.”
The team also noted that their study could help with the development of drug treatments that target the cold sensor in order to eliminate toothache as well as tooth sensitivity caused by cold temperatures.