system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why do teeth “hurt” when eating extremely sweet foods?
gpt
Note that this isn't normal. It's generally a symptom of mild or moderate gum disease and excessive plaque, resulting in recession of the gum tissue. This is usually a result of a lack of flossing and/or poor brushing routine, but pain in this instance can also be caused by cavities. 

Either way if you have frequent tooth sensitivity to cold or certain foods, its a good time to see the dentist. 

When gums are unhealthy and receded, it exposes living tooth tissue, known as Dentin, in the teeth root area beneath the layer of dead enamel on the exposed tooth surface. Often this happens in the space between teeth due to plaque trapped there. Normally the enamel is the only exposed part of the teeth and the gums cover the dentin. However bacterial overgrowth can weaken the connection between the dentin and the gum tissue causing gumline recession.

Sweets often contain citric acid as a flavoring agent. Bacteria in the mouth also are able to quickly break down sugars into lactic acid. These acids cause inflammation and irritation of living cells in the dentin. These send chemical signals in response to the central nerve in the tooth resulting in pain.