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Caries - Definition

Dental caries - Definition:


Dental caries- A dynamic process with periods of demineralization alternate with periods of remineralization.

Dental caries is defined as the irreversible multi-factorial disease of microbial origin affecting the calcified tissues of the teeth, which is characterized by demineralization of the inorganic portion and destruction of the organic constituents of the tooth, often leading to cavitation

Etiology of dental caries

CHEMICO PARASITIC THEORY by  W.D.Miller stated in 1887

Dental decay is a chemico - parasitic process consisting of two stages -

  1. The decalcification of enamel, which results in its total destruction.
  2. The decalcification of dentin as a preliminary stage followed by dissolution of the softened residue.

The lactic acid which caused the decay was derived from fermentation of starches and sugars lodged in the retaining centers on teeth.

1. Carbohydrates

Readily fermentable carbohydrates are responsible for increased caries incidence.

They are dietary in origin: Depends upon
Frequency of its ingestion,
Physical form,
Chemical composition,
Route of administration
Presence of other food components

2. Oral micro organisms which produce acid and also cause proteolysis

                  ROLE OF MICROORGANISMS

One or more different types of bacteria are involved in “initiation” of caries and a completely different species of bacteria may be involved in “progression” of caries.

  • Two gram positive coccal forms of bacteria

L.acidophilus and S.mutans .
S.salivarius, S.sanguis, S.mitior, S.millieri, L.acidophilus, Peptostreptococcus intermedius, A.naeslundi, A.viscosus
Cocci attached to filamentous organisms to produce the corn-cob type of arrangement sometimes seen in plaque
Odell, Edward. Cawson's Essentials of Oral Pathology and Oral Medicine, 9th Edition

3. Lactic Acid which caused dissolution of tooth minerals


Acids are produced by enzymatic breakdown of sugars by cariogenic bacteria.

Acids produced are – Lactic acid mainly and butyric acid to some extent.
Significance of acids due to localisation of acids upon the tooth surface.

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