Dental Caries : Definition, Causes of Dental Caries

June 6, 2012 | By | Reply More

Dental Caries : Definition, Causes of Dental Caries


Dental caries is an infectious microbiologic disease of the teeth that results in localized dissolution and destruction of the dental calcified tissues.

Path physiology Of Caries
  • Dental caries is a sugar dependent infectious disease
  • Acid is produced as a by product of the metabolism of dietary carbohydrate by bacteria which results in a drop of ph resulting in demineralization.
  • This process is reversed when the ph rises again.


There are four main criteria required for caries formation:

  1. Tooth surface (enamel or dentin)
  2. Caries-causing bacteria
  3. Carbohydrates
  4. Time

 1. Teeth

There are certain diseases and disorders affecting teeth which may leave an individual at a greater risk for caries in which the enamel does not fully form or forms in insufficient amounts in both cases, teeth may be left more vulnerable to decay because the enamel is not able to protect the tooth. The anatomy of teeth may affect the likelihood of caries formation. Where the deep grooves of teeth are more numerous and exaggerated, pit and fissure caries are more likely to develop. Also, caries are more likely to develop when food is trapped between teeth.

2. Bacteria

The mouth contains a wide variety of oral bacteria, but only a few specific species of bacteria are believed to cause dental caries: Streptococcus mutants and Lactobacilli among them. Bacteria collect around the teeth and gums in a sticky, creamy-colored mass called plaque, which serves as a biofilm. Some sites collect plaque more commonly than others. The grooves on the biting surfaces of molar and premolar teeth provide microscopic retention, as does the point of contact between teeth. Plaque may also collect along the gingiva.

 3. Carbohydrates

Bacteria in a person’s mouth convert glucose, fructose, and most commonly sucrose (table sugar) into acids such as lactic acid If left in contact with the tooth, these acids may cause demineralization, which is the dissolution of its mineral content. The process is dynamic, however, as remineralization can also occur if the acid is neutralized by saliva or mouthwash. Fluoride toothpaste or dental varnish may aid remineralization.If demineralization continues over time, enough mineral content may be lost so that the soft organic material left behind disintegrates, forming a cavity or hole.

4. Time

The frequency of which teeth are exposed to cryogenics (acidic) environments affects the likelihood of caries development. After meals or snacks, the bacteria in the mouth metabolize sugar, resulting in an acidic by-product which decreases pH. As time progresses, the pH returns to normal due to the buffering capacity of saliva   Since teeth are vulnerable during these acidic periods, the development of dental caries relies heavily on the frequency of acid exposure.

 Other Risk Factors

  • Reduced saliva is associated with increased caries since the buffering capability of saliva is not present to counterbalance the acidic environment created by certain foods. As a result, medical conditions that reduce the amount of saliva produced by salivary glands, particularly the submandibular gland and parotid gland, are likely to lead to widespread tooth decay. Examples include  diabetes mellitus, diabetes insipidus
  • Medications, such as antihistamines and antidepressants, can also impair salivary flow.
  • Radiation therapy of the head and neck may also damage the cells in salivary glands, increasing the likelihood of caries formation.

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Category: Oral Pathology

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