What Is An Abscess?


           The term abscess is used interchangeably with infection in dentistry. Infection is a bacterial process whereby germs feed and multiply unchecked in the body generating puss or gas as a waste product. There are two types of dental abscesses. When your teeth are infected, this is called an odontogenic (tooth borne) abscess. When your gums are infected, it is known as a periodontal (gum related) abscess. Both are infections, but with different causes and outcomes.

           Odontogenic abscesses (tooth infections) happen when the nerve in one of your teeth dies. Once the nerve in a tooth dies, its natural resistance to invading germs is lost. This leaves a damp, dark environment where bacteria can feed and multiply freely. There are many causes for the nerve in one of your teeth to die. Breach of your tooth's nerve chamber by fracture or decay will kill it. Chronic inflammation, as may be created by the placement of a deep filling, can kill the nerve in your tooth over a period of years or acute inflammation produced by trauma can do so almost immediately. An untreated periodontal abscess, if present long enough, can spread into your tooth from the adjacent gum and jaw bone.

Whenever there is dead tissue in your body, it will at some point become infected. A good example of this is when mountain climbers suffer from frostbite. The flesh on their frozen fingertips dies and then gangrene (festering) sets in. If the nerve in your tooth dies, it will at some point after death abscess. When this happens, puss or gas from the infection and your body's inflammatory response to it will build up pressure inside your jaw bone. This is normally painful and is commonly known as a "toothache". The pain may intensify when you lie down to sleep as blood flow to your head increases and this pressure is magnified. The built up pressure often causes the abscessed tooth to swell out of its socket slightly so that when you bite together the tooth will hit first (termed a "premature contact"). Premature contact on an abscessed tooth creates more pressure within your jaw bone and more pain. The inflammatory response may also cause some swelling around the jaw bone inside your mouth. If it has been present long enough, the abscess may be seen on an x-ray as a dark "halo" around the tip of your tooth's root where the pressure has worn away some of the surrounding jaw bone. If this wear becomes severe enough, an opening in the bone may be created through which the pressure will escape into the surrounding tissue causing your face to swell. Occasionally an abscessed tooth will present with no history of discomfort or obvious inflammation for reasons that dental science has not been able to fully explain. In these unusual cases your only complaint may be of a fractured tooth or lost filling (caused by premature contact). If this is the case, the abscess will only be discovered on an x-ray.

           Whatever the cause or symptoms, if you have an abscessed tooth, the source of the infection (the dead nerve) must be removed. While the infection can be eliminated by an antibiotic like penicillin, as long as the dead nerve remains in your mouth it is constantly subject to reinfection. There are two means of removal. If your abscessed tooth is extracted, its dead nerve leaves with it. If you wish to save your tooth and it has not been damaged beyond repair by what caused it to abscess, the dead nerve can be removed through endodontic (root canal) therapy. Your tooth will then be reinforced with a post and protected with a crown (cap) so it will look and function as a normal tooth, it just won't have any nerve tissue.


A recurrent periapical (tooth borne) abscess (arrow) of a premolar tooth. These infections are most often caused when an undetectable extra canal exists when the root canal is originally done.

           Periodontal abscesses start in quite a different manner. As noted above, infections thrive in dark, damp places where bacteria have nutrients to feed upon. In perfect health, your gingivae (gums) conform tightly to the necks of your teeth at the gumline and to the neighboring jaw bone. If an empty space occurs below your gums that is too deep for you to clean out through brushing and flossing, food particles and bacteria (in the form of dental plaque) will accumulate and fester. This is how a periodontal abscess (gum infection) arises.

           These subgingival (below the gumline) spaces are known in dentistry as periodontal pockets and they have many causes. Foreign objects, such as popcorn kernels, that become lodged beneath your gums can cause transient pockets with acute abscessing. Inflammation induced by heavy deposits of plaque and calculus (calcified plaque, also known as tartar) being left on your teeth for long periods of time can destroy the ligaments attaching the gums to your teeth and underlying jaw bone as well as the bone itself, producing pockets. Genetically linked or systemic diseases like Periodontosis (juvenile gum disease of undetermined mode) and diabetes can lead to pocketing. Odontogenic abscesses of long-standing, left untreated, can spread out of your tooth up the side of its root to cause pocketing.

           Whatever the cause of the pocketing, if it is present in your mouth it can lead to a periodontal abscess. When this happens, just as with an odontogenic abscess, gas or puss pressure will build. Here however, the pressure builds up inside the pocket, to the point where it is often partially released up through the gum line. For this reason, periodontal abscesses are frequently not as painful as tooth abscesses and they are often accompanied by bad taste and halitosis (bad breath). The pressure generally will lead to further bone loss with deeper pocketing.

           Just as with tooth infections, even though a periodontal abscess can be cleared up with antibiotics, the source must be eradicated or recurrence is almost certain. This is accomplished by either removing the affected tooth if your pocketing is so great insufficient bone support remains to retain it or through specialized periodontal treatment designed to eliminate the pockets. This therapy cleanses the pockets of plaque and calculus so that the gum tissue may reattach to your jaw bone and teeth, reversing the pockets.

           Oral infections are serious matters that should not be taken lightly. Besides the often intense pain associated with dental abscesses, there can be severe medical consequences as well. Gum and tooth infections are capable of spreading to other areas of the head and neck causing potentially life threatening illnesses such as Ludwig's Angina.




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Dr. Barry F. McArdle, D.M.D. ~ 118 Maplewood Avenue, The Captain Moses House, Suite B-7, Portsmouth, NH 03801

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