Small pieces of food — especially things like popcorn hulls — can get under your gums. If these pieces aren't removed, the area can get irritated, and even infected.
The soft tissues in the mouth are delicate and sensitive, and when they are injured, it can be very painful. Soft tissues, which include the tongue, cheeks, gums and lips, can be injured when you accidentally bite down on them, if you fall, are in an accident, or if you put food in your mouth that is too hot. Chewing on hard objects also can damage soft tissues.
Pain is one of the reasons people go to the dentist. A painful tooth can be triggered by hot or cold food and drinks. Heavy biting or grinding may fracture a tooth and cause the tooth to hurt when you chew. Sometimes, when a filling falls out, you may have a throbbing ache.
Any injury to the gums or teeth can be very painful. In some cases, however, the cause of severe dental pain is not obvious. For example, pain that comes on suddenly may be caused by particles of food that got lodged in a cavity and have started to irritate the nerve inside the tooth.
An abscess is a limited area of pus formed as a result of a bacterial infection. The body's immune system reacts to the infection, and sends white blood cells to the area to try to get rid of the bacteria.