Summary of common sense of dental care 1. A Summary of "Caring for Teeth"
In order to let children know the importance of caring for their teeth from an early age, our class actively carried out the activity of "caring for their teeth", and every team member was immersed in a good atmosphere of "caring for their teeth". Under the guidance of the teacher, I feel how to have a healthy tooth through my own experience.
1, a few days before the activity, publicize the knowledge of dental care to students; There are also posters in the classroom and blackboard newspapers about tooth protection. Let the students make a handwritten newspaper to protect their teeth.
2. Carry out the class activities of "I love my teeth, I am happy".
(1) Educate students to pay attention to oral hygiene and protect their teeth. Eat less candy at ordinary times. Especially don't eat sugar before going to bed to prevent dental caries. In addition, we should pay attention to the usual hygiene habits, do not bite fingers, do not bite pencils and other foreign bodies, and do not lick your teeth with your tongue. Teach students to develop a good habit of brushing their teeth: brush their teeth once in the morning and evening, and rinse their mouths with warm water after meals. Pay attention to the correct brushing method: brush vertically along the teeth, and then brush outside after brushing inside; Don't brush back and forth horizontally, or you will damage your gums.
(2) Show some pictures about protecting teeth to students;
(3) According to the contents mentioned in the knowledge of dental care of "Little Doctor", let students understand the difficulties and give some explanations;
(4) Hold a quiz on "tooth care knowledge" among groups to compare which group of children know the knowledge of tooth care best, and the "small teeth" escort will be rewarded;
(5) Homework assignment: to publicize certain dental health knowledge to parents.
Through activities, the students realized the importance of protecting their teeth and formed a good habit of "caring for their teeth". At the same time, it helps them master some knowledge and skills of daily tooth care, and pay attention to developing good habits of protecting teeth in daily life, which lays a solid foundation for the cultivation of good habits of students in the future.
2. Summary of "Love your teeth and protect your teeth"
The activity of loving teeth and protecting teeth summarizes the health of children and concerns every educator. The purpose of this activity is to prevent and reduce the occurrence of children's oral diseases at an early age and cultivate young pioneers' awareness of self-protection.
Through the activities, we deeply feel that the children themselves have undergone a change, the formation of a good behavior habit and the formation of an oral health behavior habit concept. Focusing on the theme of "protect your teeth at any time, start with me", our school actively promotes, organizes and implements the activities. Through a series of activities, students, teachers and parents have benefited a lot, realized the importance of paying attention to oral health and actively participated in oral health activities.
We deeply feel that parents' attention to children's oral health has been greatly improved, and we feel a change in children's own, the formation of a good behavior habit, and the formation of a concept of oral health behavior habits. First, do a good job in publicity, so that the concept of loving teeth is deeply rooted in the hearts of the people. Use the school publicity window to post the publicity map of oral health education, and organize students to watch it in each class. The red scarf radio station will broadcast the radio drama "Xiao Yi, Da Zi roaming in the tooth protection city".
Two, to carry out the "protect your teeth at any time, start from me" handwritten newspaper creation competition. * * * Received 100 works. During the activity, the team members not only gained the knowledge of tooth care and health care, but also helped the team members to develop habits and improve their ability.
Third, carry out the "I cultivate the habit of tooth care" oral health theme team meeting activities. Fourth, every class should have an oral health education class, which includes a movie propaganda film to protect teeth, promoting four good habits of "brushing your teeth with fluoride toothpaste in the morning and evening, regular oral examination, eating less desserts and sugary drinks, chewing sugar-free chewing gum and snacks after meals" and correct brushing methods.
This dental care activity was well received by parents of students. Students realize that using fluoride toothpaste can prevent dental caries, resist bacteria, strengthen teeth and keep breath fresh.
I know that eating snacks often can produce dental plaque, damage teeth, make teeth fragile and lead to tooth decay. Restricting the number of snacks can reduce the proliferation of dental plaque.
Use a healthy toothbrush to protect teeth and gums. Students are encouraged to brush their teeth every morning and evening, rinse their mouths after meals, change their toothbrushes every three months, do not eat snacks before going to bed, and check their oral habits regularly.
To a great extent, it helps students and their parents to correct bad oral hygiene habits. In the future health education, our school will continue to teach more oral health knowledge to students, improve their oral health level, and make efforts to promote the oral health development of the whole society, so that children can really develop and grow up healthily in activities.
3. Little knowledge of tooth protection
Dental care. This is a very important part of beauty. Know your teeth.
Why yellowing or blackening is necessary to protect teeth.
When the teeth turn yellow, brown or black, we must first make clear the reason for tooth discoloration. Tooth discoloration can be divided into internal coloring and external coloring.
Two kinds.
Tooth internal coloring is tooth discoloration caused by the change of tooth tissue structure or nutrition. The common diseases are pulp necrosis, mottled enamel teeth and drugs.
Tooth discoloration caused by deposition, etc. Normal teeth are covered with a milky white, translucent and shiny substance when viewed from the longitudinal section.
Ze and particularly hard structural covering, it has the function of protecting teeth, because it looks like magnetic glaze, so it is called enamel. tooth
There is a yellowish thick dentin structure in enamel, which forms the main body of teeth. There is pulp in the center of the tooth, including blood vessels.
Nerves provide nutrition and metabolism for teeth. If the nutrition of the teeth changes or is cut off, the teeth will change color.
1. Tooth discoloration caused by pulp necrosis, such as pulp bleeding and necrosis caused by tooth trauma, teeth will turn dark red.
Brown or blue gray.
2. Mottled enamel teeth are commonly known as macular teeth. Before the age of 5, drinking water with fluorine content exceeding 65,438+0/65,438+0 million per 65,438+0 liter of water will make teeth.
The structure of enamel is poorly calcified and discolored. Light mottled enamel teeth with chalky or yellowish brown patches on the enamel surface; strict
The surface of heavy teeth is rough, uneven and yellowish brown, even black, and the teeth are fragile, so the treatment is more complicated. light-spot
Glazed dentists use dilute hydrochloric acid to smear macula to change color, which can make macula shallower, but attention should be paid to protecting gums and preventing decay when applying medicine.
Erosion and burns. Severe mottled enamel teeth can be repaired with "plastic tooth veneer" or "light-cured composite resin"
3. Drugs cause tooth discoloration. Mothers in the third trimester or children under 5 years old take tetracycline and oxytetracycline more.
Antibiotics combine with calcium to form yellow or gray tetracycline, and oxytetracycline antibiotics combine with calcium to form yellow or gray.
Colored tetracycline calcium complex is deposited in the structure of enamel and dentin through dental pulp, which makes the erupted teeth yellow.
Dark gray or dark brown. The preventive measure is to take tetracycline drugs as little as possible. At present, tetracycline drugs for children have been eliminated.
Medicine.
External coloring of teeth refers to pigmentation on the surface of teeth. For example, smoking, drinking, drinking tea, and pigments in the diet mixed with saliva.
After adhering to the surface of teeth, especially the occlusal surface of teeth, pigmentation is more likely to appear in the grooves and pits of lips and tongue.
At this point, the tooth surface turns brown, yellow, gray or blue-green. The tooth surface of people who have been exposed to iron and sulfur for a long time due to professional relations can be
Calm with brown elements. There may be melanin deposition on the surface of teeth exposed to mercury for a long time. Tooth surfaces exposed to copper, nickel and chromium for a long time will
There are green * * * elements.
Brushing your teeth in the morning and evening and gargling after meals can prevent the external coloring of your teeth. Dyed teeth can be wiped with a towel or cotton swab.
Wipe the tooth surface with 3% hydrogen peroxide. Seriously, use a doctor's rubber wheel to polish and remove the coloring.
4. Tips for protecting teeth
If you want to protect your teeth, you must first understand the structure of your teeth.
Teeth are the hardest organs in the human body. It has the functions of biting, tearing, grinding food and assisting pronunciation.
There are two pairs of teeth in a person's life: one pair is deciduous teeth, the upper and lower jaws have 20 teeth, and 10 teeth. It began to erupt about half a year after birth and came out about two and a half years old. From 7 years old to 12, deciduous teeth fall off one after another. The other pair is permanent teeth, ***32, and the upper and lower jaws are 65,438+06 respectively. The deciduous teeth gradually change from the age of 6, and all the permanent teeth erupt around the age of 12 except the third molar.
The third molar usually erupts after the age of 20, also called wisdom tooth. Wisdom teeth will never come out, so 28~32 permanent teeth are normal.
Teeth are divided into three parts: crown, neck and root. The crown is the part we can see, and it is the part where the teeth are exposed outside the gums.
The surface of the crown is covered with a layer of enamel, which is the hardest tissue in the human body, and its hardness is similar to that of the time. The root is embedded in the alveolar process of the upper and lower jaws.
The root surface is covered with a layer of cementum. The neck of the tooth is a slightly thinner part between the crown and the root of the tooth, which wraps the gum.
Teeth are mainly composed of dentin, and the internal cavity is called tooth cavity. The cavity of movable teeth is filled with connective tissue, nerves and blood vessels, which are collectively called dental pulp.
Blood vessels and nerves enter and exit from the apical foramen of teeth. When suffering from dental caries, bacteria corrode enamel and dentin and enter the pulp cavity, which is unbearable.
(See Figure 37) Students should do the following to protect their teeth: 1. Develop a good habit of brushing your teeth. Rinse your mouth with warm water after meals and brush your teeth once in the morning and evening.
Don't brush your teeth too often, it will damage your teeth, and don't brush your teeth for too long. Brush cheese.
5. Little knowledge of tooth protection
Draw a row of teeth. Write something about protecting teeth. Nowadays, oral health has long been an important part of people's overall health and quality of life, and it is also an indispensable pillar to prolong people's healthy life.
Protecting and strengthening teeth is not only regarded as the top priority of oral health, but many fashionistas are even proud of their names. According to textual research, the Book of Rites written by Confucius and compiled by later generations records that "the chicken crows at first and is washed with salt", which shows that our people have been gargling with salt water every morning at the end of the Spring and Autumn Period.
This method of tooth protection is also described in A Dream of Red Mansions written by Cao Xueqin, a literary giant in China18th century. Miss Lin Daiyu, a rich girl, wipes her teeth with green salt before and after going to bed every night. It can be seen that gargling with salt water is a common method to protect teeth in ancient China.
The historical record of brushing teeth was written by Tang dynasty, and the ancient medical book "The Secret of Outer Taiwan" written in 752 AD recorded the ancient prescriptions before Tang dynasty and some new prescriptions at that time. It has been mentioned that biting off one end of a poplar branch and wiping it with medicine can make the teeth "fragrant and smooth". This should be the earliest habit of brushing teeth in China, and ancient murals in Dunhuang also have pictures of wiping teeth with fingers.
Moreover, it is said that China was the first country to use toothbrushes, which can be verified in the cultural relics unearthed from the ancient tombs of Liao. The earliest toothbrush in the world appeared in China. Ancient monks also mastered this tooth protection technology. The Buddhist sutra Hua Yan Jing even concluded that chewing poplar branches has 65,438+00 benefits, including "removing tartar" and "making the mouth fragrant".
Monks should clean their teeth like this before chanting. Li Shizhen, a famous doctor in Ming Dynasty, also pointed out in his magnum opus Compendium of Materia Medica that cleaning teeth with tender willow branches is infinitely useful.
● What foods can prevent dental caries? Fish, rice, lentils, peas and broad beans have high phosphorus content, and phosphate can form a buffer system to prevent excessive acidification of the mouth. Children should eat more foods rich in calcium, such as beans, bean products, vegetables, fish and shrimp. So as to provide enough minerals and vitamins for the normal development of teeth.
Milk and dairy products contain a lot of calcium, which can inhibit the acid production of bacteria and prevent the dissolution of calcium and phosphorus compounds in teeth. In addition, immunoglobulins and enzymes contained in milk can inhibit the growth of bacteria in the mouth.
Foods containing more fluorine include fish, shrimp, kelp, jellyfish, tea and mineral water. Fluorine can form insoluble fluorapatite with calcium and phosphorus compounds in dentin, thus preventing the acid produced by bacteria from eroding dentin. You should eat more foods that are not overcooked, because they contain more fat-soluble vitamins and minerals and need more chewing power when eating. Chewing can promote saliva secretion, help digestion and clean teeth.
You should eat less refined food (such as plum, chocolate, soda, candy, cakes, biscuits, etc.). ). Fruits, such as apples and pears, can play the role of mechanically scrubbing teeth when eaten, and wipe off bacteria attached to the surface of teeth.
In addition, pectin in fruits can also inhibit bacteria. Vegetables contain many trace elements and a lot of vitamin C, and are also very important anti-caries nutrients.
Plant fiber can reduce the adhesion of food and the formation of dental plaque through mechanical friction cleaning of tooth surface and secretion of salivary glands. In addition, vegetable oil can form a hydrophobic layer on the surface of teeth to protect teeth and prevent dentin from dissolving.
■ Simple method → The method of whitening teeth with lemon juice is as follows: After brushing your teeth every night, touch some lemon juice with gauze and rub your teeth, and your teeth will become white and bright. Lemon has a strong cleaning power and whitening effect, and contains vitamin C, which can strengthen the roots of teeth.
Students should protect their teeth and do the following: 1. Develop a good habit of brushing your teeth. Rinse your mouth with warm water after meals and brush your teeth once in the morning and evening.
Don't brush your teeth too often, it will damage your teeth, and don't brush your teeth for too long. 2. Pay attention to oral hygiene and protect your teeth.
Eat less candy at ordinary times. Especially don't eat sugar before going to bed to prevent dental caries.
In addition, we should pay attention to the usual hygiene habits, do not bite fingers, do not bite pencils and other foreign bodies, and do not lick your teeth with your tongue. 3. If your teeth are sick, you should seek medical advice in time.
If there are cavities, they should be repaired or pulled out. It is not difficult to achieve the above points, the key is perseverance.
May all students have healthy and beautiful teeth. 1. Develop good eating habits: reduce the frequency of eating sugary foods, because many bacteria will accumulate on the edges of teeth and gums, and bacteria will produce acid when using sugar, which will corrode teeth and cause dental caries.
2. Establish good oral hygiene habits: keep oral hygiene clean, master the correct method of brushing teeth, rinse your mouth after meals, and brush your teeth in the morning and evening. 3. Correct brushing angle and action: tilt the toothbrush at 45 degrees, press it between the tooth surface and gums, try to let the bristles enter the gingival sulcus and between the teeth, then brush vertically along the teeth, gently rotate the brush head, and brush each tooth in sequence for three minutes at a time.
4. Brush the outside of teeth: clean the outside of upper and lower teeth with correct brushing action and appropriate angle. Brush the upper teeth from top to bottom and brush the lower teeth from bottom to top. Each part can be brushed 4-6 times repeatedly. 5, the inside of the toothbrush: still follow the principle of brushing vertically along the teeth and gently rotating, don't just pay attention to the outside of the toothbrush, don't pay attention to the cleaning of the inside of the teeth.
6, the chewing surface of brushing teeth: with adaptability, brush the chewing surface of the upper and lower teeth in the front and back direction. 7, pay attention to the back teeth: the teeth behind the mouth also need the same attention, after cleaning all the teeth, rinse your mouth with water.
8. Choose health care toothbrush and fluoride toothpaste: the bristles of health care toothbrush are soft and elastic, and do not damage teeth and gums. Fluorine in fluoride toothpaste is combined with enamel, which makes teeth stronger and has good caries prevention effect.
6. What's your little knowledge about loving and protecting your teeth?
Easy use of toothpaste After years of research, the medical community believes that if you don't rinse your mouth thoroughly after brushing your teeth, you will ingest toothpaste residue.
However, all kinds of toothpastes used by people every day, regardless of the similarities and differences of their materials, contain friction agents, foaming agents, heating agents, thickening agents, flavoring agents, preservatives and so on. Some toothpastes also contain fluorinating agents. These preparations contain chemicals such as phosphate, calcium carbonate and magnesium carbonate, which may cause diseases such as local gastroenteritis.
In addition, children's resistance is poor, their immune function is not perfect, and their oral mucosa is particularly delicate. The use of strong toothpaste will damage the child's mouth. In addition, children are not good at gargling to remove toothpaste residue. If too many chemical components in toothpaste residue remain in the body, it will do great harm to children's growth and health. Therefore, it is best for children to gargle without toothpaste.
Some dental diseases can be treated with medicated toothpaste. But if you don't choose medicine toothpaste according to the symptoms, it will not only fail to achieve the expected purpose, but also have side effects.
Although medicated toothpaste is effective for some oral diseases, it cannot cure all oral diseases. If you use antibacterial and anti-inflammatory toothpaste for a long time, it will kill normal bacteria in the mouth while sterilizing, thus causing new oral diseases. Many medicine toothpastes contain alkaloids and substances. Long-term use will damage the oral mucosa and make the mouth, gums, tongue, lips and throat inflamed. Some medicine toothpaste tastes bitter and spicy, and long-term use will cause gastrointestinal discomfort; Some medicine toothpastes contain a certain amount of pigment, which will make teeth lose luster after long-term use.
Therefore, families should always change different brands of toothpaste. Drug toothpaste Do not abuse drug toothpaste, whether it is fluoride, anti-inflammatory, tooth protection, deodorization and hemostasis, desensitization, or other types, its role is to prevent and treat dental diseases.
Although medicinal toothpaste has a certain curative effect on oral diseases, it is harmful to use it for a long time. Such as long-term use of anti-inflammatory and tooth-protecting toothpaste such as chlorhexidine, Zanthoxylum nitidum, Scutellaria baicalensis, Tianqi, Kangzhiling, etc. It will not only make the pathogenic bacteria in the mouth resistant, but also kill the beneficial bacteria in the mouth while killing the pathogenic bacteria.
These beneficial bacteria are essential to human oral cavity. If suppressed, it will not only bring difficulties to the treatment of diseases, but also lead to new infections. For example, the common double infection is caused by long-term abuse of antibiotics. In addition, many medicinal toothpastes contain alkaloids and substances with * * * *. Long-term abuse of this kind of toothpaste will not only damage the delicate mucosa in the mouth, but also cause inflammation and even ulcers in the gums, mouth, tongue, lips and throat due to long-term strong * *.
Some medicine toothpastes have strong bitterness and spicy taste, which often cause gastrointestinal discomfort. In addition, some medicinal toothpastes often add some pigments, which will make the teeth lose luster after long-term use.
Smoking can lead to periodontal disease. Smoking can affect periodontal tissue in many ways, leading to periodontal disease. This is the conclusion of a joint investigation by the Third Hospital of Baotou Steel and Baotou Steel Hospital not long ago.
In order to explore the relationship between smoking and periodontal disease, 572 patients were investigated by the Third Hospital of Baotou Steel and the Department of Stomatology of Baotou Steel Hospital from 1998. Doctors divided 572 patients into middle-aged group and elderly group.
There were 355 middle-aged people and 2 13 smokers. 2 17 elderly people and 0/50 smokers. After investigation and comparison, the number of early periodontitis segments of middle-aged smokers is significantly higher than that of non-smokers; The number of healthy periodontal bands of smokers in the elderly group is lower than that of non-smokers, and the number of periodontal bands in the late stage of periodontitis is significantly higher than that of non-smokers.
Smokers who smoke more than 20 cigarettes a day and smoke continuously for about 20 years have significantly fewer periodontal health zones than non-smokers. The researchers concluded that smoking may be one of the risk factors for the prevalence of periodontal disease.
Researchers believe that the formation of smoke spots in smokers' mouth is beneficial to stone deposition, and local plaque will also aggravate periodontal disease. Tobacco contains a variety of harmful substances, and the chemical components in the smoke can directly * * * periodontal tissue or enter the blood circulation, causing chronic damage to periodontal tissue.
Experts pointed out that although periodontal disease is a minor illness, intracranial infection and septicemia caused by periodontitis are not uncommon in clinic. Therefore, in order to protect teeth, smokers are advised to quit smoking.
The standard of oral health Oral health is an important part of human health. According to the World Health Organization, dental health means that there are no structural and functional abnormalities in teeth, periodontal tissue, oral cavity and maxillofacial region.
Oral health standards are: clean teeth, no cavities, no pain, normal gum color and no bleeding. It can be seen that oral health refers to good oral hygiene, sound oral function and no oral diseases.
The World Health Organization once pointed out that in order to achieve the goal of national health care by the year 2000, in order to protect teeth, we must start with the prevention of dental diseases, develop good oral hygiene habits, regularly check and treat dental diseases, timely repair missing teeth, and regularly clean teeth, so as to maintain the sound function of teeth. Once dental problems occur, you must go to a clinic with advanced equipment, strict disinfection and high professional and technical level, which can comprehensively treat all kinds of dental caries, pulp diseases, periodontal diseases and various denture restorations (advanced porcelain teeth) so as not to delay the opportunity and cause regret.
September 20th is national love teeth day. Do you know the phenomenon of "three more and three less" in oral health-"There are more people who care about oral health, but fewer people have correct oral health knowledge; There are more people who insist on brushing their teeth every morning and evening, but few people brush their teeth effectively; There are more people willing to spend money on oral health, but fewer people know how to spend money. " In China, the adult's periodontal health rate is as high as 97%, but more than 60% people have never seen a dentist, and less than 2% people have regular oral examination and cleaning.
How to protect oral health reasonably and correctly in daily life? The answer is to watch your mouth! On the one hand, tooth decay can be effectively prevented by effective brushing to clean teeth and remove dental plaque and plaque. On the other hand, rinse your mouth in time after meals, remove the scale film deep between your teeth, reduce the generation of dental plaque and inhibit the generation of bad breath.
In social situations, we should also pay attention to keeping our breath fresh. Fresh breath is becoming an important symbol of modern life civilization. The formation of mature dental plaque usually takes about 2 days, if it is firm.
7. Knowledge of dental care
1. Develop good brushing habits. Rinse your mouth with warm water after meals and brush your teeth once in the morning and evening. Don't brush your teeth too often, it will damage your teeth, and don't brush your teeth for too long. Pay attention to the correct brushing method: brush vertically along the teeth, first brush the inside and then brush the outside. Don't brush back and forth horizontally, or you will damage your gums.
2. Pay attention to oral hygiene and protect your teeth. Eat less candy at ordinary times. Especially don't eat sugar before going to bed to prevent dental caries. In addition, we should pay attention to the usual hygiene habits, do not bite fingers, do not bite pencils and other foreign bodies, and do not lick your teeth with your tongue.
3. If your teeth are sick, you should seek medical advice in time. If there are cavities, they should be repaired or pulled out.
It is not difficult to achieve the above points, the key is perseverance. May all students have healthy and beautiful teeth.
8. Take care of your teeth and protect them
Alcohol is the enemy of fresh breath, so try to avoid drinking alcohol or using alcoholic mouthwash. Clean your teeth regularly:
Tooth washing is to remove the tartar hidden around the tooth flesh and the stains on the tooth surface, such as tea stains, coffee stains, cigarette stains and so on. However, it should be noted that some stains cannot be removed, such as stains that go deep into the teeth. Habitual flossing:
When tooth flesh is red, swollen and inflamed, it is easy to cause bleeding during tooth washing or brushing. Please don't worry, if you can use dental floss and electric toothbrush correctly and take effective brushing methods, tooth inflammation and bleeding can be improved. Master the correct method of brushing teeth:
Use a reasonable toothbrush, brush your teeth vertically, both inside and outside. Rinse your mouth carefully after meals:
Gargling can remove food debris and some soft dirt, keep the mouth clean and give full play to its physiological functions. Chew fully:
Especially eating foods with high vitamin content can secrete saliva, wash away dirt in the mouth, play the role of gums, make teeth clean and periodontal tissue healthy. Bullet:
Knock your teeth ten times every morning to enhance the resistance of your teeth and periodontal tissue. * * * Gums:
After brushing your teeth in the morning and evening, gently press your cleaned fingers on your gums for a few minutes. Eat less sulfur-containing food:
Through scientific research, it is found that dairy products, onions, garlic and other foods containing a lot of sulfur are prone to produce anaerobic bacteria that cause bad breath. Chewing gum should be xylitol;
In fact, sugary chewing gum is more likely to cause tooth decay or bad breath. Therefore, choosing chewing gum containing xylitol can effectively strengthen teeth and ensure fresh breath. Fresh breath, not "aggressive", is also necessary for your interpersonal public relations.
9. Tips for protecting teeth
If you want to protect your teeth, you must first understand the structure of your teeth. Teeth are the hardest organs in the human body. It has the functions of biting, tearing, grinding food and assisting pronunciation. There are two pairs of teeth in a person's life: one pair is deciduous teeth, the upper and lower jaws have 20 teeth, and 10 teeth. It began to erupt about half a year after birth and came out about two and a half years old. From 7 years old to 12, deciduous teeth fall off one after another. The other pair is permanent teeth, ***32, and the upper and lower jaws are 65,438+06 respectively. The deciduous teeth gradually change from the age of 6, and all the permanent teeth erupt around the age of 12 except the third molar. The third molar usually erupts after the age of 20, also called wisdom tooth. Wisdom teeth will never come out, so 28~32 permanent teeth are normal.
Teeth are divided into three parts: crown, neck and root. The crown is the part we can see, and it is the part where the teeth are exposed outside the gums. The surface of the crown is covered with a layer of enamel, which is the hardest tissue in the human body, and its hardness is similar to that of the time. The root is embedded in the alveolar process of the upper and lower jaws. The root surface is covered with a layer of cementum. The neck of the tooth is a slightly thinner part between the crown and the root of the tooth, which wraps the gum. Teeth are mainly composed of dentin, and the internal cavity is called tooth cavity. The cavity of movable teeth is filled with connective tissue, nerves and blood vessels, which are collectively called dental pulp. Blood vessels and nerves enter and exit from the apical foramen of teeth. When suffering from dental caries, bacteria corrode enamel and dentin and enter the pulp cavity, which is unbearable. (See Figure 37) Students should take the following measures to protect their teeth:
1. Develop good brushing habits. Rinse your mouth with warm water after meals and brush your teeth once in the morning and evening. Don't brush your teeth too often, it will damage your teeth, and don't brush your teeth for too long. Brush cheese