Some patients with severe thermal (hot/cold) sensitivity are having severe pulpal (nerve) inflammation that is an indication for root canal treatment. After the pulp has been removed as part of root canal treatment, the tooth is unable to feel thermal stimuli, so this kind of sensitivity will cease immediately.
Other patients may also have inflammation or infection (an abscess) around the root of the tooth requiring root canal treatment. This will manifest as tenderness on chewing or biting on the affected tooth. Normally this should resolve after root canal treatment but if there is significant bone loss associated with the inflammation, this can take many months to resolve.
If the tooth is cracked, pain on chewing (especially hard food) will be very pronounced. Root canal treatment may be needed for a cracked tooth, if the crack has progressed into the pulp chamber. However, the tenderness on biting may never fully resolve, as cracked teeth may be more prone to periodontal (gum) infections.
