How do you tell if a tooth is dying under a crown?

Detecting whether a tooth is dying beneath an existing dental crown can sometimes be challenging because the protective cap shields the tooth from direct visual inspection, but several distinct clinical symptoms usually signal internal nerve degeneration or pulp necrosis. The most common indicator is prolonged or spontaneous sensitivity to hot and cold temperature extremes, where a sharp ache lingers long after the stimulus has been removed, or a dull, throbbing pain deep within the jaw that intensifies when pressure or biting force is applied to the tooth. Patients may also notice noticeable darkening or discoloration of the gum tissue directly surrounding the crowned tooth, which often points to internal bleeding or tissue breakdown within the dying root canal system. In more advanced stages of infection, a small, pimple-like bump called a fistula or dental abscess may form on the gumline, accompanied by a foul taste, persistent bad breath, or pus drainage, requiring an immediate professional dental evaluation utilizing diagnostic x-rays and vitality tests.