When a tooth is infected, it can present a wide variety of unpleasant symptoms that can range from mild to severe. Common symptoms include: - Persistent and Recurring Toothaches — Severe pain in the teeth should always be addressed by a dental professional; it may be the result of a sinus infection or a tooth injury, but it may also be caused by a cavity if the pain continues for more than a week. If the tooth pain persists for even longer, it may be caused by an infection. - Pain or Temperature Sensitivity — An infected tooth is more prone to hot and cold temperatures as there is less protective enamel present and possible nerve root exposure. - General Sensitivity/Jolts of Pain — The two main reasons sensitivity occurs include: the pulp within the tooth is inflamed, and there is a crack in the tooth. - Fever — If fever-like symptoms are present without other cold or flu-like symptoms, an infected tooth may be the culprit. - Swelling and Tender Lymph Nodes — Swollen lymph nodes are caused when the teeth are exposed to too much bacteria. - Seeing Holes or Deep Pits Within the Teeth — When a cavity or infection starts to form, it starts off as a small white spot on the surface of the tooth; as the infection gets worse, holes or deep pits begin to appear. - Deeply Stained Teeth — While red wine, coffee, and dark-colored foods can all stain teeth, discolored spots can be a sign of infection.