What Are Periodontal Diseases

From the The American Academy of Periodontology http://www.perio.org/consumer/2a.html

Periodontal (gum) diseases, including gingivitis and periodontitis, are serious infections that, left untreated, can lead to tooth loss. The word periodontal literally means "around the tooth." Periodontal disease is a chronic bacterial infection that affects the gums and bone supporting the teeth..

Periodontal disease can affect one tooth or many teeth. It begins when the bacteria in plaque (the sticky, colorless film that constantly forms on your teeth) causes the gums to become inflamed.

In the mildest form of the disease, gingivitis, the gums redden, swell and bleed easily. There is usually little or no discomfort. Gingivitis is often caused by inadequate oral hygiene. Gingivitis is reversible with professional treatment and good oral home care.

Untreated gingivitis can advance to periodontitis. With time, plaque can spread and grow below the gum line. Toxins produced by the bacteria in plaque irritate the gums. The toxins stimulate a chronic inflammatory response in which the body in essence turns on itself, and the tissues and bone that support the teeth are broken down and destroyed. Gums separate from the teeth, forming pockets (spaces between the teeth and gums) that become infected. As the disease progresses, the pockets deepen and more gum tissue and bone are destroyed. Often, this destructive process has very mild symptoms. Eventually, teeth can become loose and may have to be removed.

Types of Periodontal Disease

There are many forms of periodontal disease. The most common ones include the following. 

Gingivitis
Gingivitis is the mildest form of periodontal disease. It causes the gums to become red, swollen, and bleed easily. There is usually little or no discomfort at this stage. Gingivitis is reversible with professional treatment and good at home oral care. 

Mild Periodontitis
If gingivitis, the mildest form of periodontal disease, is left untreated, it can advance to periodontitis. In the mild stage, periodontal diseases begin to destroy the bone and tissue that support the teeth. 

Moderate to Advanced Periodontitis
Moderate to advanced periodontitis develops if earlier forms of the disease like gingivitis and mild periodontitis are left untreated. This is the most advanced form of the disease in which extensive bone and tissue loss occurs.

Juvenile Periodontitis
Localized juvenile periodontitis (LJP) occurs in adolescents and is characterized by the rapid loss of bone around permanent teeth. Ironically, youngsters with LJP form very little dental plaque or tartar. Generalized juvenile periodontitis is often considered a disease of young adults, although it can begin around puberty. It is characterized by marked inflammation and heavy accumulations of plaque and calculus. Pockets can form around the affected teeth, filling with infection. If not treated early, infection can lead to bone loss which may cause the teeth to become loose.

Good oral hygiene (brushing your teeth and flossing, for example) reduces the risk of cavities. Regular oral hygiene also helps reduce the risk of gum disease, which is caused by the same bacteria (found in dental plaque) that causes tooth decay and cavities.

Dental plaque is a sticky deposit of bacteria, mucus, food particles, and other irritants found around the base of the teeth. The toxic effects produced by the bacteria in dental plaque cause both tooth decay and gum disease. (Dental plaque is composed of different material from the plaque found in arteries. The plaque found in arteries is composed mainly of fats and proteins.)

Gingivitis is inflammation of the gums (or gingiva), the soft tissue that surrounds the base of your teeth. Gingivitis is usually caused by the buildup of plaque. The toxic effects of the bacteria cause gums to become irritated, red, and swollen and the gums may bleed easily. The plaque also forces the gums to recede from the teeth.

Gingivitis can develop into the more serious condition called periodontitis. Periodontitis is inflammation of membranes around the base of the teeth. Periodontitis can cause erosion of the bone holding the teeth in place resulting in tooth loss.

From the Centre for Oral Health Sciences, Malmo University, Malmo, Sweden and the School of Dentistry, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark. http://www.odont.ku.dk/basic.periodontology/pathpocket.html

1.    The remaining tooth associated epithelium has been transformed to a pocket epithelium which is characterized by proliferations of sc rete peg formations and by an increased permeability for cells and fluid. In some areas the connective tissue is devoid of epithelium and there may be a direct contact between the pocket environment and the connective tissue. Lateral to the pocket epithelium in the connective tissue there is a dense accumulation of immune cells of various types.   Plasma cells predominate the immune infiltrates. The collagen in the connective tissue close to the pocket epithelium is dissolved and there are relatively fewer fibroblasts compared to healthy periodontal conditions.  The mechanisms behind the tissue damage appear to associate with the release of metalloproteinases from accumulated leukocytes and substances from the local immune process in the gingiva. The actual attachment loss is believed to be caused by the dissolution of collagen fibers which allow the epithelium to proliferate over the tooth surface.

2.     The progression rate of periodontal attachment loss varies. In some periods the destruction of the attachment is rapid in others more slow.  The lack of appropriate methodology prevents the registration of minor progressions and it is only when the loss of attachment has reached a certain level that it can be registred clinically. Changes in attachment level of 2 mm or more is generally indicative of that a progression has taken place.  The pathological periodontal pocket is characterized by an ongoing inflammatory reaction which will vary over time.  On the tooth surface there are accumulations of dental plaque. The composition of the subgingival microflora varies but around 10 bacterial species have been suggested to be particular periodontal pathogens. The composition varies both in the lateral and apical coronal direction.   The subgingival ecology is different on the tooth surface, in the pocket exudate and on the epithelium of the pocket lining. It is therefore difficult to take a microbial sample which is reflecting the tissue response in relation to the composition of the flora.

3.     In addition current research has demonstrated that the subgingival bacteria also may invade dentinal tubules in areas where the disease process has removed the cementum.  Such intradental reservoirs of microorganisms may favor recolonization of the tooth surface after treatment.   Calculus formation subgingivally creates increased surfaces for bacterial colonization and subgingival calculus may contribute indirectly to the etiology of periodontitis.  A continuous migration of leukocytes into the pocket occur. The polymorphonuclear leukocytes predominate this cellular exudate.  The leukocytes form a wall between the gingival tissues and the surface of the tooth associated dental plaque.   The leukocytes protect the gingival tissues towards major invasion of bacteria, There is only a short junctional epithelium at the apical part of the pocket.

For more information regarding the role of oral infections in systemic diseases  such as heart disease, stroke, pre-term, low birth weight infants, diabetes, respiratory diseases, and osteoporosis see http//www.perio.org/consumer/mbc.top2.htm.

Question:
If bacteria can grow and divide within the dentinal tubules of vital, periodontally diseased teeth, what does that mean for non-vital, endodontically treated teeth?  One also has to ask, if the bacteria involved in periodontal disease can contribute to all these systemic diseases, what about the bacteria residing in the dentinal tubules of avital, endodontically treated (root canal) teeth.  As Dr. Walter Loesche and colleagues so eloquently pointed out, most, if not all, periodontally diseased teeth harbor bacteria within the dentinal tubules and these bacteria constitute a "pathogenic reservoir" form which reinfection of the periodontal pocket can occur (see references below). If vital, but periodontally diseased teeth can harbor such pathogens, what about non vital root canal teeth. Surely, any dead tissue allowed to remain in an environment such as the mouth with its favorable conditions for bacterial growth, is bound to become infected with bacteria regardless of how well it is embalmed.

References

Bacterial invasion in root cementum and radicular dentin of periodontally diseased teeth in humans. A reservoir of periodontopathic bacteria. Adriaens PA, De Boever JA, Loesche WJ. J Periodontol 1988 Apr;59(4)222-30. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=3164373&dopt=Abstract

Ultrastructural observations on bacterial invasion in cementum and radicular dentin of periodontally diseased human teeth. Adriaens PA, Edwards CA, De Boever JA, Loesche WJ.J Periodontol 1988 Aug;59(8)493-503.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=3171862&dopt=Abstract