There are many causes for teeth and/or their surrounding structures to become painful or develop “sensitivity.” Tooth pain comes from two potential sources: the dental pulp (nerve) and/or the surrounding periodontal tissues (bone and gums).
Pulpal pain
The network of nerves and blood vessels inside a tooth is called the dental “pulp.” When the pulp becomes inflamed or irritated, people may experience an elevated level of sensitivity; this means that even small stimuli, such as drinking a glass of water, cause the tooth to hurt for a prolonged period, sometimes lasting a minute or longer. This heightened state of tooth sensitivity is referred to as “pulpitis,” meaning “inflammation of the pulp.” What causes pulpitis?
- Mild trauma to a tooth, such as placing a filling or a crown. This type of pulpitis typically subsides within days or weeks after the initial trauma. In this case, we refer to the issue as “reversible pulpitis” because it eventually goes away. The pain or hypersensitivity in the tooth usually lasts less than a minute after the stimulus (hot, cold, chewing, etc…) is applied, therefore it is not constant pain. People generally find the tooth becomes less and less sensitive as time goes on, as the pulp tissue heals and becomes less inflamed. This is kind of like falling down on your knee; at first, the skin is bruised and sensitive to touch. After a week or so, it’s much less so. Within two weeks the knee may be completely normal again.
- Tooth grinding, also referred to as “bruxism” can cause pulpitis. Grinding can cause sensitivity for different reasons. If teeth are worn down on the chewing surface as a result of grinding, the inner part of the tooth that contains nerve endings (called dentin) can be exposed. These exposed nerve endings cause pulpal sensitivity. In a similar fashion, the grinding and bending stress on the teeth may cause the enamel and/or dentin to erode away at the gum line, thus expose nerve endings on the root. This type of tooth sensitivity is the result of nerve endings within the dentin being exposed. Chronic grinding also causes the pulp to become inflamed and more sensitive simply from the mechanical trauma of the teeth clashing into one and other.
- Cracks in teeth may also cause pulpitis, especially if the trajectory of the crack goes close to or intersects the pulp. Cracks not only allow parts of the tooth to flex and thus stimulate nerves but they also create a pathway for fluids and bacteria to reach the pulp tissue and cause sensitivity. This type of pulpal pain may be short-lived if the crack quickly propagates beneath a cusp, or it may cause persistent pain if the crack propagates toward or intersects the pulp.
Periodontal pain
Periodontal tooth pain is pain that comes from the bone and/or gums around the tooth, as opposed to the nerves within the tooth itself. This type of pain is generally more mild, sometimes characterized as dull or diffused, as opposed to pulpal pain, which is often characterized as sharp or stabbing. The causes of periodontal pain are:
- Biting trauma: when teeth sustain overloading, (for instance when a filling or crown is “too high”), the small fibers which hold the tooth within its boney socket, called the periodontal ligament get bruised. The bruised periodontal ligament causes the tooth to hurt when it is chewed on. When the overloading of teeth is the result of bruxism all or several of the teeth may be tender to bite on.
- Tooth abscess: if the pulp tissue within a tooth becomes necrotic (dead), the resulting bacterial infection of the pulp causes puss to form and pressure to build within the tooth and its boney socket. Because this space is confined, a small amount of pressure due to puss formation may cause intense pain in the nerves of the surrounding periodontal tissues. If, on the other hand, the puss finds an escape route from the bone and gum tissue, pressure doesn’t build and the pain may be mild or absent.
- Gum abscess: if the gum tissue becomes infected, perhaps from gum disease, this pain may be mistaken for pain emanating from a tooth. Gum abscesses are rarely painful and are commonly detected from a bad taste or smell coming from the gum tissue. This is probably why most gum disease goes undetected for patients who rarely visit the dentist.
- Root Fracture: when a crack from the enamel and dentin travels beneath the gums to affect the root, the root may split. This split or crack in the root creates a pathway for bacteria to travel down into the bone surrounding the root. Since the dental pulp may already be dead, there is commonly no sharp stabbing pain as most people would imagine. Instead, the pain or discomfort from a root fracture is usually described as a low-grade ache in the gum area. The crack in the root can only be seen on an X-ray if the two halves of the root have physically separated and are in line with the direction the X-ray was taken. Otherwise, the only radiographic evidence of the split root is the damaged bone adjacent to the root.
This list is a list of some of the most common sources of tooth-related pain but is by no means a complete list. Please feel free to call us if you’d like us to diagnose your tooth pain.