What is the cause of dental caries?

Dental caries is often said cavities, or cavities, most cases are due to the infection factors factors, of course, is the most common bacterial infections, the incidence of dental caries, actually has a very close contact, and oral hygiene of course, bacteria are also different, such as Streptococcus, actinomyces, the etiology of dental caries introduction:
1, bacteria
The bacteria is a necessary condition for dental caries, generally there are two types of cariogenic bacteria, is a genus of acid producing bacteria, including Streptococcus mutans, Actinomyces and Lactobacillus, can make the decomposition of carbohydrates to produce acid, inorganic lead to tooth demineralization; the other is a gram positive cocci, can destroy organic matter, after long-term effect can make the tooth formation of cavity. At present, the main cariogenic bacteria are Streptococcus mutans, others include actinomyces, Lactobacillus and so on.
Bacteria adhere mainly to the surface of the tooth with plaque. Oral retention of carbohydrates were degraded after a polymerization to produce high viscous dextran, forming plaque matrix, on the other hand, the acid production of tooth demineralization, plaque composition is more complex, in addition to a large number of bacteria, and sugar, protein, enzyme and other substances.
2, oral environment
The oral cavity is the external environment of the teeth, which is closely related to the occurrence of caries, and the main functions are the food and saliva.
(1) the food is mainly carbohydrates, is associated with the formation of plaque matrix, is also the main energy bacteria in plaque, bacteria can use carbohydrates (sucrose) and acid metabolism, synthesis of extracellular polysaccharide and intracellular polysaccharide, organic acids produced in favor of acid production and acid bacteria the growth, also conducive to demineralization of dental hard tissue, the polysaccharide of bacteria in adhesion and promote the accumulation of the tooth surface, and the exogenous sugar deficiency, provide a source of energy. Carbohydrates are therefore the material basis for dental caries.
(2) the salivary fluid is under normal circumstances, the saliva has the following several functions:
The act of mechanical cleaning reduces bacterial accumulation.
Bacteriostasis, direct inhibition or inhibition of plaque on the surface of teeth.
The acid action is neutralized by substances such as bicarbonate.
The anti - acid action can increase the acid resistance and reduce the solubility of the teeth through calcium, phosphorus and fluorine.
When the quantity and quality of saliva changes, the rate of caries can be affected. In clinical practice, the incidence of caries in patients with xerostomia or saliva secretion increases obviously. Patients with maxillofacial radiotherapy may have multiple dental caries due to destruction of the salivary glands. On the other hand, when the amount of lactic acid in the saliva is increased or the amount of bicarbonate is reduced, it is also beneficial to caries.
3 host
The tooth is a target organ in the process of dental caries, there is a direct relationship between the degree of mineralization and the morphology, structure and caries, such as dental fissure and mineralized teeth caries bad easily, and the degree of mineralization is better, the appropriate amount of tissue containing fluoride dental caries resistance is strong; on the other hand, there is a close relationship between the structure and the body of the teeth, especially in the development, development and structure not only affects the teeth, but also has great influence on the flow and the flow rate of saliva and its composition, which is also an important part in the occurrence of dental caries.

4, time
The incidence of dental caries is a long process, the formation of cavity usually takes 1.5-2 years from early caries to clinical, so even if the cariogenic bacteria, suitable environment and susceptible to caries exist at the same time, also will not happen immediately, only these three factors also exist for a long time, can cause caries, so the time factor has important significance in the occurrence of dental caries.
The prevention of oral saliva on dental caries has a great role in the presence of saliva can sterilization, cleaning and bacteria, that is to say, the saliva under normal circumstances, the role is to protect, but if it is unable to maintain normal levels in saliva, also can appear to cause disease.