What Is Dental Caries?

Caries, commonly known as worm teeth and tooth decay, are bacterial diseases, so it can cause pulpitis and periapical inflammation, and can even cause alveolar and jaw inflammation. If not treated in time, the lesions continue to develop, forming a cavity, and eventually the crown is completely destroyed. Untreated caries do not heal on their own, and the end result of their development is tooth loss.

Shen Song	(Deputy Chief Physician)	Department of Dentistry, Peking University Stomatological Hospital
Liu Yingyi	(Attending physician)	Department of Dentistry, Peking University Stomatological Hospital

Dental caries, commonly known as worm teeth and tooth decay, is a bacterial disease, so it can secondary to pulpitis and periapical inflammation, and can even cause alveolar and jaw bone inflammation. If not treated in time, the lesions continue to develop, forming a cavity, and eventually the crown is completely destroyed. Untreated caries do not heal on their own, and the end result of their development is tooth loss.

Dental caries is a progressive lesion of tooth hard tissue caused by the combined effect of multiple factors in the oral cavity, which is manifested as the evolution of inorganic demineralization and decomposition of organic matter, and changes from color to formation of substantial lesions as the disease progresses. It is characterized by a high incidence and wide distribution. It is the main common disease of the oral cavity and one of the most common diseases in human beings. The World Health Organization has listed it with cancer and cardiovascular diseases as the three major human diseases.

Causes of dental caries

At present, the etiology theory of caries is a quadruple factor theory, which mainly includes bacteria, oral environment, host (that is, parasites including parasites, viruses, etc.) and time. The basic point is: cariogenic food sugar (especially sucrose and refined carbohydrates) is closely attached to the tooth surface, on the acquired membrane formed by salivary protein. In this kind of anatomical structure and biochemical, biological The physical characteristics not only can be firmly adhered to the tooth surface, but also can have sufficient time at the appropriate temperature to produce acid in the deep layers of the plaque, invade the teeth, demineralize them, and then destroy the organic matter and generate caries.

Clinical manifestations of dental caries

Clinically, the changes in the color, shape, and quality of caries can be seen, and the quality becomes the main. The color and shape changes are the result of qualitative changes. As the disease progresses, the lesions enter the dentin from the enamel, and the tissue is continuously destroyed and disintegrated. The caries hole is usually divided into three stages: shallow, medium and deep caries according to the degree of caries.

Superficial caries

Also known as enamel caries, caries is limited to enamel. Initially, it appears as chalky plaques caused by demineralization on the smooth surface in the early stage, and it is yellow-brown due to coloration, and the ink-like dispersion at the pits and grooves. Generally, there is no obvious caries. Shallow holes confined to the enamel were present, there were no conscious symptoms, and there was no response to exploration.

2. Medium caries

The caries has reached the superficial level of dentin, there are obvious caries holes in clinical examination, and pain can be detected. Painful reactions to external stimuli (such as cold, heat, sweetness, acid and food embedded) can occur. The pain immediately after the stimulus is removed Disappeared without spontaneous pain.

3. Deep caries

The caries has reached the deep level of dentin, which is generally manifested as a large and deep caries cavity, or a small and deep entrance with extensive damage. The response to external stimuli is heavier than medium caries. However, after the stimulus source is removed, the pain can be immediately relieved. No spontaneous pain.

4. Caries

On the X-ray film, there is a black transmission area. For those who are difficult to diagnose (such as adjacent caries), the X-ray film can assist the diagnosis.

Dental caries

If it is difficult to determine the caries, you can take X-rays, and the caries can be seen in black. Those with conditions can use optical fiber transillumination, electrical impedance, ultrasound, elastic mold separation, dyeing and other techniques to improve the accuracy and sensitivity of early diagnosis of caries.

Differential diagnosis of dental caries

Dental caries should be distinguished from dental hypersensitivity.

Dental hypersensitivity mainly manifests as irritation and pain, which is caused by brushing, eating hard objects, sour, sweet, cold, and hot stimuli, especially the most sensitive to mechanical stimulation. The most reliable diagnostic method is to use a sharp probe to slide on the tooth surface to find one or more allergic areas. Foreign countries reported a mechanical stimulator that uses screws to adjust the pressure of stainless steel needles to test the sensitivity of teeth, and also uses an electronically controlled thermometer to test the person. However, so far, the sensitivity of the teeth can only be expressed by the subjective feelings of patients.

Caries Treatment

The purpose of caries treatment is to stop the disease process, prevent it from continuing to develop and restore the inherent shape and function of the teeth. Due to the special tooth structure, although it has the ability to remineralize, it has no self-repairing ability for substantial defects. Except for a few cases of available medicines, filling surgery, inlays or artificial crowns are required to restore the shape and function according to the scope and volume of tooth defects.

Drug treatment

Drug treatment is a method of suppressing the development of dental caries based on the removal of caries. It is suitable for superficial caries that have not yet formed holes in permanent teeth, and superficial and medium caries holes in premature teeth. Commonly used drugs include silver ammonium acid and sodium fluoride.

2. Silver amalgam filling

For teeth that have formed a substantial defect, filling is currently the most widely used and effective method. The basic process can be divided into two steps: first, removing the carious tissue and the weak tooth tissue that has lost support, and according to certain requirements Make the cavity into a reasonable shape. Then it is filled with filling material to restore its inherent shape and function. Suitable for filling back teeth and anterior teeth in hidden areas.

(1) Basic principles for preparation of cavities To remove carious tissue and prevent secondary caries. One of the hole-making effects is similar to debridement. The carious tissue must be removed, and the cavity should be established on healthy dental tissue to prevent secondary infection.

Protect the pulp. The pulp is the living tissue with sensation and metabolism. Due to the close relationship between the dentin and the pulp, the pulp tissue will be stimulated to varying degrees when it is cut. In severe cases, it can cause pulp congestion and inflammation. Response, so care should be taken to protect the pulp during operation to avoid and reduce irritation.

Preparation of resistance and retention forms, because the teeth need to bear the chewing function after restoration, so after filling the restoration should meet two requirements. On the one hand, it can keep the restorations from loosening and falling off for a long time. Neither the object nor the remaining tooth tissue will be broken due to the chewing force, that is, it should be resistant. Both should be taken into consideration when preparing the cavity.

(2) Filling repair process (silver amalgam) removes the carious tissue and establishes the shape of the cavity; preparation of resistance and retention shapes; cavity modification and cavity cleaning; cavity detoxification; pad base; ;polishing.

3. Composite resin filling

It is suitable for filling anterior teeth and posterior cavity that does not bear the chewing force. The main points of filling are: preparing a certain cavity shape; the cavity with a moderate degree or above needs to be used as a base; the mixing equipment should be clean and dry. Use a non-metal mixing knife, pay attention to the proportion of the components, and mix thoroughly; Prevent moisture during filling to avoid air bubbles, and it is advisable to use polyester film or cellophane to compact the material, and finally polish it.

4.Acid etching method for photosensitive composite resin filling

Water cement, calcium hydroxide preparation, etc. cover the exposed dentin; Use 35% or 50% phosphoric acid to etch the tooth surface for 1 to 2 minutes; Thoroughly rinse the dry tooth surface to prevent recontamination; After the photosensitive composite resin is irradiated with visible light for 20 to 40 seconds, it is cured, and finally the shape is polished.

5.Inlay

A restoration suitable for a dental cavity is made of metal or other materials and is embedded in the cavity, which is called an inlay; the cover inlay is the cover inlay. Applicable to: those with large posterior cavities or the possibility of fracture of the posterior teeth; the filling of the adjacent conjunctival cavity can not repair the adjacent key with adjacent teeth; as a semi-fixed abutment. The main points are: remove the carious tissue and hang the glaze column; the hole depth is not less than 2.5mm, and there is a 45 ° hole edge slope, and the opening angle of the hole wall is less than 5 °; nails and furrows can be added to help fix (4) Those with thin walls and weak tips make full-face preparations; (5) Make model wax models, embed them in time, and use continuous mold casting as much as possible.

Dental caries prevention

1. Brush teeth in the morning and evening, and develop a good habit of mouthwash after meals;

2. Eat less acid-stimulating foods and avoid snacks before going to bed;

3. Eat less sugary foods such as sugar, chocolate, biscuits, etc.

4. Do not eat too much hard food to avoid tooth wear;

5. Participate in physical exercise regularly and check the oral cavity regularly. Generally, people over 12 years old should check it once a year.

6. The usual diet should include more nutritious foods rich in calcium and inorganic salts, and eat high-fiber rough foods as much as possible.

Dental caries data

The fourth national oral health epidemiological survey released in 2017 also showed that the prevalence of permanent dental caries in 12-year-old children in China was 34.5%, an increase of 7.8 percentage points over ten years ago. The prevalence of deciduous tooth caries in 5-year-old children was 70.9%, an increase of 5.8 percentage points over ten years ago. The incidence of caries in children has shown an upward trend ^[1] .