Yes, a sensitive tooth can be fixed; the method of repair depends on the cause of the sensitivity. For example, if a tooth is sensitive because it is cracked or broken, repairing the tooth with a root canal or other restorative procedure can completely resolve the problem with sensitive teeth. It is easier to fix one sensitive tooth than a set of sensitive teeth; one tooth can be treated and repaired, but if multiple teeth are involved, tooth sensitivity is likely caused by weakened enamel. Repairing compromised enamel can be difficult, and may require multiple treatments.