Other reasons can be divided into: congenital factors: the key to tooth development is the pregnancy and infancy of the fetus-the embryonic period of teeth. If drugs or other improper things are used at this time, it will affect the development of enamel, such as common tetracycline teeth and dental fluorosis. Acquired factors: Because there are many bacteria that can secrete sticky substances on the surface of teeth, the dirt left after daily diet will gradually stain the teeth. Yellowing or blackening. Substances that "contaminate" teeth, such as cigarettes, wine, tea, coffee, etc. Some small folk remedies: 1. Rinse your mouth with salt water after brushing your teeth every morning and evening; Or brush your teeth and add some salt directly to the toothpaste, not too much. After a few days, the teeth will turn white, and after one month, there will be obvious effects. 2. Grind cuttlefish bone into powder and use it on toothpaste when brushing your teeth every day. Brush your teeth with diluted white vinegar, rinse your mouth and rinse your teeth with diluted vinegar water for 20 minutes before brushing your teeth, but I personally disapprove of this method. Yes, many people like to bleach their teeth with acidic liquid. However, long-term use of acidic liquids will have a strong corrosive effect on teeth, which will lead to the loss of calcium in teeth, which is not conducive to strengthening teeth. At present, there is no tooth whitening product that can naturally make teeth "white and crystal clear" unless other scientific and technological means are adopted. However, these methods will wear some natural teeth and even damage the pulp. Therefore, before deciding to do whitening treatment, you must go to a trusted medical institution for treatment. Different people have different requirements. Here are some specific methods: Basic introduction of whitening toothpaste: toothpaste containing whitening ingredients. Cost: tens of yuan. Whitening time: Brush your teeth at least twice a day. Advantages; High safety factor, convenient use and low price. Disadvantages: slow effect, unsatisfactory whitening effect and slight allergy. Precautions: The brushing time can be prolonged when used, so that the whitening ingredients in toothpaste can act on the tooth surface as much as possible. Applicable people: people with slightly polluted and discolored teeth. Retention time: half a year whitening index: two-star tooth whitening paste Basic introduction: Japanese innovative products, easy to use, just rub back and forth on the tooth surface. It contains special substances, which can prevent tooth decay, has high safety factor and is quite convenient to use. Disadvantages: It takes time to witness the whitening effect at present. Note: Use twice a day, and do not overuse it. Applicable people: people with slight tooth pollution. Storage time: half a year. Whitening Index: Basic Introduction of Erxing Deep White Toothpaste: Decolorization with pharmaceutical ingredients can make yellow teeth and black teeth lighter after continuous use for a period of time. The cost is convenient to use, the price is moderate, it is relatively safe, the time is short, and the effect is quick. Disadvantages: it will produce different degrees of dentin hypersensitivity. Precautions: If there are serious allergic phenomena such as swelling and pain of gums and bleeding. , stop using it immediately. Applicable people: people with light pigmentation, such as people who drink tea and coffee for a long time, smokers and patients with mild tetracycline teeth. Retention time: six months to one year. Whitening index: basic introduction of Samsung laser tooth whitening: using high-tech special laser technology, using high-concentration whitening agent and high-calorie laser to catalyze hydrogen peroxide, and using oxidation principle to remove tooth surface pigment. Cost: about 1800 yuan. Whitening time: 8 minutes advantage; Can improve tooth whitening by 5-8 color steps, and is very safe for gums and oral tissues. Compared with the general tooth whitening method, the effect is more prominent and the effect is faster. Disadvantages: it is expensive, requires professional evaluation before operation, and is sensitive to different degrees. Note: Avoid eating easily dyed, supercooled and overheated food within 24 hours after operation. Applicable people: patients with moderate tetracycline teeth, drug-induced discolored teeth and dental fluorosis. Retention time: about two years. Whitening index: four-star cold light whitening. Basic introduction: Using special cold light technology and special optical lens, all harmful ultraviolet rays and infrared rays are separated and acted on whitening agent, which makes it produce redox effect quickly. Cost: 1800 yuan. Whitening time: 30~45 minutes. Advantages; It can improve the tooth color by 5~ 14, and take effect on the spot. Disadvantages: Consumers with heavy tooth pigments need a second cold light treatment and have different degrees of allergies. Precautions: The doctor should be informed of the sensitive state of teeth before treatment, and the dentist can control the dosage of drugs and the length of cold light irradiation according to the actual situation. Applicable people: patients with moderate and mild tetracycline teeth, drug-induced discolored teeth and dental fluorosis. Retention time:.