How teeth sense the cold

David Clapham, vice president and chief scientific officer of the Howard Hughes Medical Institute (HHMI) in the United States and an international team of scientists have figured out how teeth sense the cold and pinpointed the molecular and cellular factors involved. In both mice and humans, tooth cells called odontoblasts contain cold-sensitive proteins that detect temperature drops, the team reports in the journal Science Advances. Signals from these cells can ultimately trigger a jolt of pain to the brain.

The work offers an explanation for how one age-old home remedy eases toothaches. The main ingredient in clove oil, which has been used for centuries in dentistry, contains a chemical that blocks the “cold sensor” protein, says electrophysiologist Katharina Zimmermann, who led the work at Friedrich-Alexander University Erlangen-Nürnberg in Germany.

Developing drugs that target this sensor even more specifically could potentially eliminate tooth sensitivity to cold, Zimmermann says: “Once you have a molecule to target, there is a possibility of treatment”.

Teeth decay when films of bacteria and acid eat away at the enamel – the hard, whitish covering of teeth. As enamel erodes, pits called cavities form. Instead of cracking a tooth open and solely examining its cells in a dish, Zimmermann’s team looked at the whole system: jawbone; teeth; and, tooth nerves. The team recorded neural activity as an ice-cold solution touched the tooth. In normal mice, this frigid dip sparked nerve activity, indicating the tooth was sensing the cold.

That sharp sensation hasn’t been as extensively studied as other areas of science, but Clapham says: “It is important and it affects a lot of people.”