SmileScoutA second or two of sensitivity to cold, especially at the necks of teeth, is common as enamel thins or gums recede with age, hard brushing, or acid. Many people manage it with a sensitive-teeth toothpaste and a softer brush.
It is not “normal” to put up with pain that lasts after the cold is gone, that hits one tooth when you bite, or that is getting worse week by week. That pattern is more typical of a cavity, a crack, or an inflamed nerve.
If sensitivity is new after a filling or whitening, give it a week or two and use a sensitive toothpaste. If it doesn't settle, go back to the dentist who treated you.
References
Grounded in standard dental textbooks and professional guidance. These are general sources, not a substitute for an in-person exam.
- Roberson TM, Heymann HO, Swift EJ. Sturdevant's Art and Science of Operative Dentistry.
This is general information written by a dentist, not personal medical advice. If you are in pain, swollen, or unsure, see a qualified dentist.