The word “CARIES” is derived from the Latin word meaning ‘ROT’ or ‘DECAY’. Dental caries, also known as dental decay or a cavity is an infectious microbiological disease that results in localized demineralization of the inorganic portion and destruction of the organic structures of the tooth.  Today, caries is one of the most common diseases throughout the world.

What causes dental caries

Various theories have been given to explain the dental caries but most commonly accepted theory is chemoparasitic theory given by Miller. According to this theory bacteria causes the fermentation of food and produces acid. This acid causes the dissolution of the tooth surface resulting in caries.
Dental Caries is a multifactorial disease. Various factors responsible for the carious process are:

1. Tooth surface

   i) Morphology
   ii) Composition
   iii) Position

2. Saliva

   i)  Composition
   ii) Quantity
   iii) pH
   iv) Viscosity

3. Dental Plaque

4. Diet

   i) Physical factors
   ii) Local factors

Tooth surface

 If the tooth has deep pits and fissures it is more prone to caries as compared to the tooth which has shallow pits and fissures. The teeth which are not well aligned or are rotated cannot be cleaned properly. Food impaction is more and they are caries prone. A tooth is more prone to caries if it has less acid resistant enamel due to age or low fluoride intake, or if the roots have been exposed by gum recession.


Saliva also influences the incidence of caries. Saliva acts as a cleaner of teeth as it quickly washes away food debris from the mouth. If the salivary flow is less as in dry mouth or the viscosity of saliva is more then the incidence of caries increases. Saliva has some antibacterial properties which influences the caries incidence.

Dental plaque

It is the main culprit to cause caries. Plaque is a soft bacterial deposit which is formed on the teeth when they are not properly cleaned. Plaque is an example of biofilm. Plaque holds the caries causing bacteria and the acid produced by them close to the tooth, which causes decalcification of the tooth. It also prevents the saliva’s antibacterial property to act on the bacteria causing caries as it forms the protective layer around the bacteria.


 It is also one of the most important factors. Refined sticky diet which sticks to the teeth is more cariogenic as the microbes get more time to ferment the food to produce acid which causes the decalcification of the teeth and hence the caries. Diet rich in roughage causes less caries as it helps in fast clearing of food from the oral cavity. Fluoride, vitamin A,B Complex, K ,D are considered to inhibit the caries incidence to some extent.

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