There are four major causes of tooth decay and caries
Why do I have tooth decay (tooth decay)? There are currently four recognized causes of tooth decay, which are the oral environment, bacteria, host, and time.
At present, the accepted theory of the etiology of caries is the theory of four factors, which mainly includes bacteria, oral environment, host and time, and its basic point is: cariogenic foods (especially sucrose and refined carbohydrates) are tightly attached to the acquired membrane formed by saliva protein on the tooth surface in sugar, and the anatomical structure and biochemical and biophysical characteristics of the tooth surface can not only be firmly attached to the tooth surface, but also have enough time to produce acid in the deep layer of plaque at a suitable temperature, erode the tooth, and demineralize it. This in turn destroys organic matter and produces cavities.
1. Oral environment
The oral cavity is the external environment of the teeth, which is closely related to the occurrence of caries, in which food and saliva play a leading role.
(1) Food is mainly carbohydrates, which are not only related to the formation of plaque matrix, but also the main energy source of bacteria in plaque, bacteria can use carbohydrates (especially sucrose) metabolism to produce acids, and synthesize extracellular polysaccharides and intracellular polysaccharides, the organic acids produced are conducive to the growth of acid-producing and acid-resistant bacteria, and are also conducive to the demineralization of tooth hard tissue, polysaccharides can promote the adhesion and accumulation of bacteria on the tooth surface, and provide energy sources when exogenous sugar is deficient. Therefore, carbohydrates are the material basis for the occurrence of caries.
(2) Saliva Under normal circumstances, saliva has the following functions:
Mechanical cleaning reduces the accumulation of bacteria.
The bacteriostatic effect directly inhibits or inhibits the attachment of plaque on the tooth surface.
The antacid effect is neutralized by the contained bicarbonates and other substances.
The anti-dissolution effect enhances the anti-acid ability of the tooth through the calcium, phosphorus, fluoride, etc., and reduces the solubility.
When the quantity and quality of saliva changes, it can affect the caries rate, and it can be seen clinically that the caries rate of patients with xerostomia or saliva secretion is significantly increased.Patients undergoing maxillofacial radiation therapy may have multiple dental caries due to destruction of the salivary glands; On the other hand, when the amount of lactic acid in saliva increases, or the bicarbonate content decreases, it is also conducive to the occurrence of caries.
2. Bacteria
It is a necessary condition for the occurrence of caries, and it is generally believed that there are two types of cariogenic bacteria, one is acid-producing bacteria, which are mainly Streptococcus mutans, Actinomycetes and Lactobacillus, which can decompose carbohydrates and produce acid, resulting in tooth inorganic demineralization; The other is gram-positive cocci, which can destroy organic matter and cause cavities in the teeth after a long-term effect. At present, the main cariogenic bacteria are recognized as Streptococcus mutans, and others include Actinomycetes, Lactobacillus, etc.
Bacteria adhere to the tooth surface mainly with the help of plaque. After the carbohydrates in the oral retained food are degraded, on the one hand, polymerization produces highly viscous dextran to form a plaque matrix, and on the other hand, acid production demineralizes the teeth, and the composition of plaque is relatively complex, in addition to a large number of bacteria, there are sugars, proteins, enzymes and other substances.