Because something has exposed the dentin - the layer full of tiny tubes that run straight to the nerve, giving cold water a direct line in.
Cleveland Clinic names the routes: enamel worn down, gums receding, aggressive brushing, acids, whitening overuse - and the bigger problems it can signal: cavity, gum disease, or a cracked tooth. A brief zing across several teeth is classic sensitivity; a deep, lingering ache in one tooth is a nerve question for a dentist this week. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper .
What to do
Common questions
Why do my teeth hurt with cold water?
Because something has exposed the dentin - the layer under your enamel that is laced with tiny tubes running straight to the nerve, so cold water gets a direct line in. Cleveland Clinic names the usual exposure routes: enamel worn down over time, gums pulling back from the teeth, or the common shortcuts - aggressive brushing, acid-heavy drinks, whitening overuse. Sometimes sensitivity is a sign of a bigger problem: a cavity, gum disease, or a cracked tooth. The shape of the pain reads like a clue: brief zing across several teeth, fading in seconds - classic dentin sensitivity; deep, lingering ache in one tooth long after the cold is gone - nerve inflammation, a dentist question this week. The fixes scale to the cause: desensitizing toothpaste (potassium nitrate) used daily for two to four weeks, a softer brush, and a dental exam to rule out the cavity-or-crack scenario. New sensitivity is information, not a quirk.