The most common cause of dental pain is tooth decay, a bacterial infection that can spread through many parts of the tooth, and even into the gum tissue. Traumatic damage and gum disease can also result in tooth pain.
The only sure way to know what's causing tooth pain is to see a dentist, who will ask detailed questions about what you're feeling and perform diagnostic tests, such as x-rays, to try and identify the exact source of the pain. However, there are some general ways to describe the sensations you may be experiencing — and their potential cause.
Severe Pain/Root Canal Emergencies
Lingering pain after eating hot or cold foods usually indicates disease in the pulp tissue deep inside the tooth. Deep decay or physical trauma to the tooth may have allowed bacteria to infect the pulp tissue or compromise the pulp vitality. As nerves inside the pulp tissue die, the pain may go away, but the infection won't — in fact, it can spread and cause significant damage. Make an appointment to see a dental professional as soon as possible; a root canal may be needed to ease the pain and preserve the tooth.
Sharp pain when biting down on food can be caused by severe tooth decay, a loose filling, a crack in the tooth, or possibly by damaged pulp tissue inside the tooth. It should be evaluated by a dentist as soon as possible. Depending on the cause, treatment may involve filling, bonding, root canal therapy, or other procedures.
Toothache
A severe sinus headache or congestion from colds or flu may cause you to experience symptoms such as a dull ache or pressure in the upper teeth and jaw. When the illness goes away, the dental distress should cease too. Tooth clenching or grinding (bruxism) has also been known to cause this type of discomfort. If you have these habits, you may want to have a nightguard made at the dental office to protect your teeth and jaws from too much force.
No matter what type of tooth pain or discomfort you are experiencing, it is important to seek treatment if it persists.
Related Articles

A Severe Toothache You may think a painful toothache that goes away on its own is no longer cause for concern. However, it's still worth a visit to the dentist. The disappearance of pain could mean that the nerve tissue deep inside the tooth has died, yet an infection is still present... Read Article

Tooth Pain? Don't Wait! Pain is a protective response that informs the body that something is wrong. Tooth pain, specifically, is caused by a reaction of the nerves inside a tooth's pulp chamber, with the severity dependent upon the type and degree of the stimulus. This article gives some examples of pain symptoms and their possible causes... Read Article

Tooth Decay — A Preventable Disease Tooth decay is the number one reason children and adults lose teeth during their lifetime. Yet many people don't realize that it is a preventable infection. This article explores the causes of tooth decay, its prevention, and the relationship to bacteria, sugars, and acids... Read Article