Pulp diseases

The life or death of a tooth depends on the health of the pulp. This network of nerves, blood vessels, and tissues occupies a hollow central chamber that extends from the crown of the tooth to its roots. The branch of dentistry that specializes in preventing and treating pulp problems is called endodontics.

The pulp nourishes the surrounding dentin via specialized cells called odontoblasts. These cells also relay sensory information, which is why injury or damage near the pulp evokes pain.

Types of pulp damage

The pulp can be damaged in a number of ways. Among the most common are undetected tooth decay and advanced periodontal disease. Abrasion and erosion can also wear away the tooth's hard outer layers, leaving the pulp vulnerable. The pulp may inadvertently be injured when your dentist grinds a tooth in preparation for a deep filling or restoration. And of course pulp trauma occurs when a tooth is broken or knocked out.

Pulp damage is categorized as either reversible or irreversible. Its consequences can range from mild tooth sensitivity to complete nerve death of the tooth or even infection of the surrounding tissues. Symptoms vary according to the extent of the damage and can include pain, fever, prolonged sensitivity to hot or cold, swelling or tenderness of the gums, and cracked or discolored teeth.

Hypersensitivity

Although tooth sensitivity is a hallmark of pulp injury, hypersensitivity does not in itself mean that the pulp is damaged. It's a signal that the dentin has been exposed, allowing sensations of heat, cold, and irritation to reach the tooth's nerves.

Tooth sensitivity diminishes naturally with age. To reduce sensitivity, you might try one of the many toothpastes made for sensitive teeth. The effects of these products accrue over time, so it may take several brushings before you feel any relief. Also, active ingredients vary from brand to brand, so if one brand isn't helpful, try another.

As an alternative, your dentist can apply a fluoride sealant to the crown of the tooth. The sealant covers the exposed dentin and should protect against pain. If the discomfort is extremely bothersome, your dentist may suggest that you apply the sealant to your teeth at home for several nights, using a specially made mouthpiece. If all else fails, root canal therapy can resolve the problem.

Pulpitis

Pulpitis is an umbrella term for all forms of pulp inflammation. The pulp may be irritated by decay in the nearby dentin or by periodontal disease. Often pulpitis is reversible. In some cases, a natural coating of dentin will form over the pulp to shield it from the irritant, and the nerve will recover without treatment.

In situations where the pulp cannot heal itself, pulpitis is classified as irreversible. A bacterial infection in the pulp usually kills the nerve. The infection then spreads through the dead tissue in the root canal (the channels in the root portion of the tooth containing the pulp) and passes through the opening at the end of the root into the surrounding tissues. A cavity then forms in the alveolar bone and fills with pus. This pocket of infection is called an abscess. The pressure from the swelling tissue and the mounting pus forces the tooth slightly upward. At this point, severe pain, fever, weakness, and facial swelling are almost always present. Root canal therapy or removing the tooth are the only ways to prevent the infection from invading other parts of the body.

Diagnosing pulp disease

The description you give of your symptoms will form the basis of your dentist's diagnosis. The severity, nature, duration, and location of the pain all offer clues about the extent of pulp damage. Your dentist will look for visual clues, such as cracked or discolored teeth and changes in the gum tissue. Your dentist may also try exposing the tooth to stimuli such as heat, cold, or a light electrical current. A response indicates the nerve is still alive.

Your dentist may inject a local anesthetic at the base of the tooth in question. If the pain goes away, that shows the tooth was the right one. If the pain persists, the dentist will repeat the injection at the base of the next tooth and will continue until the diseased tooth is identified.

Although x-rays can shed light on the interior structure of the tooth, they cannot reveal whether the pulp is healthy. Pulpitis must be very advanced before bone degeneration shows up on the film.

Treating pulp disease

Once pulp disease is discovered, your dentist will try to stop the spread of infection and, if possible, save the tooth. The type of intervention depends on the extent of the disease.

Root canal therapy

In this procedure, an endodontist removes diseased pulp tissue and seals off the chamber to prevent further infection. The entire process — the root canal procedure itself and restoration of the tooth — takes two to three office visits to complete.

During the first visit, the endodontist injects a local anesthetic and isolates the tooth from the rest of the mouth with a thin sheet of rubber called a dam. The endodontist cuts a hole through the top of the tooth and removes the pulp material (see Figure 5); cleanses the root canal of bacteria, tooth fragments, and tissue; and then shapes the root canal. If the tooth has more than one root, the process is performed on all of them. The endodontist injects an antiseptic (and sometimes antibiotics) into the pulp chamber to kill remaining bacteria. Then he or she dries the root canal and places filling material (usually a rubber-like material called gutta-percha) in the chamber and root canals. Finally, he or she will place a temporary restoration in the access hole of the tooth. This completes the actual root canal portion of the therapy.

Figure 5: How root canal therapy is done

Root canal therapy is done to remove damaged pulp and prevent further infection. The procedure usually requires one or two office visits. At the start of the process, the dentist drills a hole to access the pulp (A). After cleansing the pulp chamber using special instruments and irrigation liquids, the dentist fills the pulp chamber and root canals with a permanent filling material known as gutta-percha (B). Then he or she places an amalgam or composite filling in the rest of the pulp chamber; this is sometimes called a "core buildup." Finally, the dentist restores the treated tooth, often with a crown.

While most endodontists will try to complete this procedure in just one visit, occasionally it requires two visits. The gutta-percha can be placed only if the root canal is dry and free of infection. If this isn't the case (for example, pus or blood may still be present), then the endodontist will delay this step. Instead, during the first visit, he or she will pack an antibiotic paste into the root canal and close the pulp chamber with a temporary filling. On the second visit, your endodontist will remove the temporary filling and fill the chamber and canal with gutta-percha to prevent the tooth from becoming infected again. He or she may also insert a plastic or metal post into the root canal to give the tooth extra support.

After the root canal treatment is complete, you will need to visit your restorative dentist so he or she can place a permanent restoration on the tooth. The material used for the restoration will depend on the size of the access hole as well as the type and location of the tooth. Your dentist may choose an amalgam or composite restoration, a crown, or both. Premolars and molars in particular should be crowned after root canal therapy to prevent the tooth from breaking.

Pulpotomy

In a pulpotomy, your dentist removes the damaged pulp from the crown portion of your tooth, but leaves the pulp that's in the root intact. This procedure is used primarily in children and young adults because it allows the root to continue to grow. However, it's suitable only if the inflammation is mild to moderate, and the tooth may still need root canal therapy at a later date.

Pulp capping

If decay has penetrated through the dentin, the dentist may try to save the pulp by coating it with a layer of medication and giving the tooth a chance to heal on its own before placing a permanent filling. This is called pulp capping.

Know the warning signs of dental infection

Infections in and around the teeth can be caused by advanced decay or periodontal disease, or they may be a complication from oral surgery or tooth extraction. Because an infection can spread to the gum and mouth tissues as well as other parts of your head and neck, seek help at the earliest signs of a problem.

Call your dentist immediately if you have

pain, heat, and swelling in the area

fever

foul odor and pus.

Get emergency attention if you have

difficulty speaking or swallowing

swelling of the tongue or under the tongue.

When a tooth needs to be pulled

Despite the best efforts of you and your dentist, there are times when a tooth is so decayed or damaged that the only remedy is extracting it. You may also need to have fragile, diseased, or impacted teeth removed before a prosthesis can be fitted.

While your general dentist may perform simple extractions, he or she may refer you to an oral surgeon for more complicated ones. For a simple extraction, your dentist injects a local anesthetic into the gum and loosens the tooth with hand instruments, such as pliers and short levers. Once the dentist has loosened the tooth sufficiently, he or she pulls it out in one piece.

For teeth that cannot be removed in a single piece, local or general anesthesia can be used, depending on your preference and that of your dentist. If the tooth is impacted, your dentist may have to cut the gum and bone to reveal the tooth. Then he or she breaks the tooth into pieces, removes it from the gum, and stitches the wound shut.

Your mouth will need a few days to heal from the trauma of the extraction. Here are some things you can do to ease your discomfort and help the process along:

Expect a small amount of bleeding.

Avoid activities that could dislodge the clot where the tooth was removed. These include smoking, drinking through a straw, or rinsing your mouth vigorously.

Apply a cold cloth or ice pack to your face to reduce swelling.

Avoid brushing and flossing the area that is healing. Brush and floss normally in the rest of your mouth.

Take pain medication as directed by your dentist.

Review Date: 2007-04-01

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