What is the cause of caries in primary molars?

It has to be said that some diseases occurring in the teeth in life will have a great impact on life. For example, some friends suffer from toothache. You know, even men may not be able to bear toothache. After going to the hospital for a check-up, I found out that I had tooth decay, which required professional treatment and should not be treated casually by myself. So, what is the cause of caries in primary molars?

Caries, commonly known as tooth decay, is a bacterial disease that can lead to pulpitis and apical periodontitis, and even cause inflammation of the alveolar bone and jawbone. If not treated promptly, the lesions will continue to develop, forming caries holes, and eventually the crown of the tooth will be completely destroyed and disappear. The ultimate result of its development is tooth loss. The characteristics of dental caries are high incidence and wide distribution. It is a common oral disease and one of the most common diseases in humans. The World Health Organization has listed it as one of the three major preventable diseases in humans, along with tumors and cardiovascular diseases.

Causes

The currently recognized theory of the etiology of dental caries is the four-factor theory, which mainly includes bacteria, oral environment, host (that is, parasites including parasites, viruses and other organisms that parasitize on it) and time. The basic point is that cariogenic food sugars (especially sucrose and refined carbohydrates) are tightly attached to the tooth surface, forming an acquired film by salivary proteins. This acquired film is not only firmly attached to the tooth surface, but also has enough time and temperature to produce acid deep in the plaque, attacking the teeth, demineralizing them, and further destroying organic matter, resulting in caries.

1. Bacteria

It is a necessary condition for the occurrence of dental caries. It is generally believed that there are two types of dental caries bacteria. One is the acid-producing bacteria, mainly Streptococcus mutans, Actinomyces and Lactobacillus, which can decompose carbohydrates to produce acid, leading to demineralization of tooth inorganic matter; the other is Gram-positive cocci, which can destroy organic matter and cause tooth cavities after long-term action.

2. Oral environment

The oral cavity is the external environment of teeth and is closely related to the occurrence of caries, among which food and saliva play the dominant role.

(1) Food

It is mainly carbohydrates, which are related to the formation of plaque matrix and are also the main energy source for bacteria in plaque. Bacteria can use carbohydrates (especially sucrose) to metabolize to produce acid and synthesize extracellular polysaccharides and intracellular polysaccharides. The organic acids produced are beneficial to the growth of acid-producing and acid-resistant bacteria, and are also beneficial to the demineralization of dental hard tissues. Polysaccharides can promote the adhesion and accumulation of bacteria on the tooth surface and provide an energy source when exogenous sugar is lacking.

(2) Under normal circumstances, saliva has the following functions: ① mechanical cleaning effect; ② antibacterial effect; ③ anti-acid effect; ④ anti-dissolution effect.

Changes in the quantity and quality of saliva can affect the caries prevalence. Clinically, the caries prevalence in patients with xerostomia or salivary secretion is significantly increased. Patients who undergo maxillofacial radiotherapy may have multiple caries due to damage to the salivary glands; on the other hand, an increase in the amount of lactic acid in saliva is also conducive to the occurrence of caries.

3. Host

Teeth are target organs in the process of caries. The morphology, mineralization degree and tissue structure of teeth are directly related to the occurrence of caries.

4. Time

The development of dental caries is a long process. It usually takes 1.5 to 2 years from the initial stage of dental caries to the formation of clinical cavities. Therefore, even if cariogenic bacteria, a suitable environment and a susceptible host exist at the same time, dental caries will not occur immediately. Only when the above three factors exist at the same time for a considerable period of time can dental caries occur.