If you are not informed about what to expect following a filling, you may be alarmed if your tooth suddenly becomes symptomatic after a filling. Many times patients complain that they had no pain before a procedure and their sensitivity to cold began immediately after the filling. It is not uncommon to have sensitivity to cold after a filling, and it can be completely normal. When a cavity is removed from a tooth, the pulp tissue (nerve) can become temporarily inflamed. When the pulp becomes inflamed, it can respond to cold stimuli more rapidly and with hypersensitivity. As long as the sensation is short lasting and only when provoked, you should expect the symptoms to subside within a few days. The inflammation of the pulp in this case is reversible and no further treatment is required.
If you are having prolonged hypersensitivity, such as pain to cold that lingers for 30-60 seconds, or the pain is spontaneous without provocation, the pulp may be irreversibly inflamed. A pulp with irreversible inflammation is incapable of healing and requires root canal therapy.