General

Most toothaches are caused by injury to the dental pulp, commonly referred to as the "nerve" in the tooth.  Mild toothaches occur in each of us at some point in our lives, but normally will subside with time, as the pulp heals.  They can be caused by tooth decay or trauma to the tooth, but often are "idiopathic", meaning they have no known cause.  (Less commonly wisdom teeth or other teeth may cause pain unrelated to the nerve in the tooth, but this is usually caused by periodontal infection, i.e. infection of the gums and surrounding bone of a tooth.)

Toothaches usually start out as mild sensitivity, usually only to cold, then progress to sensitivity to heat, after which the tooth often hurts without any provocation, and may progress to excruciating pain. (Reputedly, the two worst sources of pain in humans are toothache and renal colic (passing kidney stones)).  Intense pain is an indication of severe inflammation in the dental pulp, and eventually results in necrosis, or death of the pulp (i.e. nerve).

In rare instances, pulpal necrosis may occur in the absence of symptoms, however is almost always later accompanied by sensitivity to biting and chewing.  In contrast to the earlier symptoms of hot/cold sensitivity, this pain is the result of inflammation in the bone at the tip of the root of the tooth where the nerve enters.  Once the pulp in the tooth has died, however, the tooth itself can feel no pain.  Instead, the pain is actually eminating from pressure in the bony socket around the root of the tooth, hence the sensitivity to biting.  This is why many toothaches seem to sponataneously dissappear, only to reappear at a later date, once bone inflammationwhich is secondary to pulpal necrosis is present.  Usually the inflammation in the bone is a reaction to bacterial infection of the dead pulpal tissue, and typically progresses in severity to become an abscess.

An acute abscess is characterized by severe pain, which is worsened by biting or tapping the affected tooth.

chronic abscess is usually characterized by slight to moderate pain, but with the presence of a "gum boil" located in the gum near the root tip of the affected tooth.   A chronic abscess will typically follow an acute abscess, once a drainage route, called a fistula, has formed. This allows drainage of pus from the abscess.  The severe pain subsides because the pressure is relieved.

It is important that any abscesses be treated, as they can progress to life-threatening illnesses.

Assessment of Toothaches

Mild toothaches and/or sensitivity often disappear over time without any treatment.  In fact, most sensitivity to cold is actually caused by gum recession and not any injury to the pulp.

The roots of teeth do not have the dense, protective layer of enamel over their surfaces.  Thus, if the gums recede past the point at which the enamel ends, the highly sensitive bare root surface will become exposed in the mouth, at times causing great sensitivity of short duration especially to cold liquids.  This type of sensitivity also often presents as pain when scraping a fingernail along the gumline of a tooth.  Fortunately, root sensitivity usually gets better with time, sometimes aided by the use of a sensitivity toothpaste.  (Gum recession, however, is not considered a normal process, and if progressive in nature, usually is a sign of periodontal disease.)

Sensitivity in a tooth to sweets often indicates a deep cavity in the tooth, or leaky filling.  This can usually be corrected simply by placing a new filling in the tooth.

If there is tooth sensitivity that lingers well beyond the point of stimulus (e.g. cold), exquisite sensitivity to heat, or spontaneous pain, this is strongly suggestive of irreversible inflammation of the dental pulp, or "nerve."  In other words, the nerve is probably dying, and cannot repair itself.  This condition of "irreversible pulpitis" can usually be detected before the severe pain sets in, and therefore best treated early if the diagnosis is very clear.

Treatment of Toothaches

There are only two treatment options available to alleviate pain caused by inflammation or necrosis of the dental pulp.

First, but usually less favorable, is removal of the tooth.  This option is normally reserved for situations in which the tooth is not functional or capable of being restored to function.  This is often the case with the wisdom teeth.

The second option, and by far more common, is root canal therapy.  Contrary to popular myth, root canal treatment is rarely painful.  Rather, it relieves the pain in the tooth.  Many recent advancements in this field have made this a relatively simple, atraumatic procedure.  In contrast to even the recent past, most root canal treatments can now be performed completely in a single appointment, usually with no or only mild post-operative discomfort.

What is Root Canal Therapy?

Root canal therapy, or endodontic treatment, involves removing the dental pulp from the canal or canals which run the length of the respective roots of each tooth.  The procedure is performed under local anesthetic through a small hole made in the top of the tooth in back teeth, or in the back of the tooth for front teeth.  After the pulp has been removed, the canals are carefully cleaned and sterilized, and then are filled with a biologically inert substance called gutta percha, which seals off the canals to prevent bacterial infiltration.

In cases where an acute abscess is present, and the pulp is necrotic (i.e. dead), the infection can usually be drained through the small hole made in the top of the tooth, which relieves the pressure and pain.  Once the infection has been cleared up with the aid of antibiotics, the treatment can then be completed.

It is important to recognize that even though the "nerve" in the tooth may no longer exist, a tooth will still be able to function normally.  However, endodontically treated teeth tend to have more brittle and weaker tooth structure than vital (live pulp) teeth.  It is for this reason that it is almost universally recommended that these teeth be reinforced with a post and core, and covered with a crown.

Crowns

A crown, often referred to as a "cap", is a tooth restoration that fits over an entire tooth (the area above the gumline, that is).  Crowns are usually placed on teeth which are badly broken down or weakened.  Crowns are also almost always placed on teeth that have undergoneroot canal therapy.  Most crowns done today are either all-porcelain, or porcelain fused to a metal substructure to add strength.  Invariably,  the cosmetic results are excellent, especially using the exceptional materials now available.

Procedure:

In order to fit a crown over an existing tooth, the tooth must be prepared by reshaping it into a form which will allow the crown to be seated onto the tooth.  This typically involves shaving down most of the enamel covering of the tooth under local anesthetic.  Once the tooth is reshaped, an impression is taken from which a plaster model of the tooth will be made for use in the dental laboratory.  A temporary crown will then be cemented onto the tooth, to remain in place until the permanent crown or crowns are completed by the laboratory.

Crowns typically require two to three weeks of lab time.  Once ready, your temporary crown is removed, and the permanent one cemented in place, after checking for correct shade and fit.

Bridges:

Often a tooth or teeth will be missing between other teeth.  This gap can be filled with a permanent functional replacement tooth by using the teeth on either side of the space as a means of support.  This type of restoration is called a bridge.   A bridge is composed of crowns placed on the teeth adjacent to the gap, connected by an artificial tooth or teeth which replace the missing ones.  The crowns which support the bridge are called abutments.  The replacement teeth which are connected to the crowns are called pontics.  Bridges are permanently cemented in place, and, even though the teeth are connected, they appear to be separate and distinct.

Bridges are often confused with partial dentures.  Partials, however, are removable and usually grip the supporting teeth with visible metal clasps.

Bridges have been the standard treatment for replacement of one or two missing teeth for several decades.  They tend to be highly predictable in longevity (often last a lifetime), and even for front teeth are excellent esthetically.  The chief drawback is that the abutment teeth must be prepared for crowns, which often involves shaving down a virgin tooth which would not otherwise need a crown.  Fortunately, this is more of a theoretical and psychological disadvantage than an actual one, and before the introduction of dental implants, also unavoidable.  Now that the success rate of implants is so high, however, many patients choose implants over bridges.  In many instances this is a choice based on personal preference, as the cost is usually comparable for a bridge vs. an implant supported crown.

Procedure:

The procedure for making a bridge is almost exactly the same as that for crowns, except for the time factor involved.  The reason for this is that usually two teeth must be prepared for crowns instead of one.

Note:  Most bridges are done in order to replace only one or two missing teeth, but bridges can also be made to replace multiple missing teeth in certain circumstances.

Periodontal Disease

Gum disease, or periodontal disease is the leading cause of tooth loss in the United States today. In its early stages, periodontal disease is simply a detachment of the gum tissue from the root surface of the tooth, which is a progressive process that begins with gingivitis. This detachment is caused by the collection of bacteria (or plaque) that adhere to the surface of the tooth, and gradually break down the seal which sticks the gum tissue to the tooth. This is an insidious process which occurs, usually over a period of years, and is rarely, if ever, painful.In its more advanced stages, periodontal disease is a chronic infection, which takes the form of bone degeneration in the socket around the root of the affected tooth, and results in looseness of the tooth. This condition is usually characterized by red, swollen gums which bleed easily, and often the presence of hard black deposits of calcified bacterial plaque on the surface of the teeth, called calculus.

Severely affected teeth, which usually are very loose as a result of a longstanding periodontal infection, can only be treated by removal.

As with many things in our lives we often take our teeth for granted until a problem arises.  The incidence of most dental diseases, however, can be significantly reduced by taking preventive measures.  This includes regular oral hygiene such as brushing and flossing, and also dental cleanings & check-ups.  Most problems with the teeth and gums are preceded by warning signs which can be detected by a dental professional, and if addressed early, can ward off more serious and expensive problems in the future.  Professional cleanings are very important because even though you may think that your oral hygiene is impeccable, there are many areas which you may be consistently missing when you brush and floss.

Also, in the process of examining your mouth, a dentist will look for signs of oral cancer or other signs of systemic disease that can manifest themselves in the mouth.  Diseases as diverse as leukemia and lead poisoning can often be detected before any other noticeable symptoms arise.