Collection of excellent lecture reports by Ningxia science experts: Oral health care for teenagers - dental caries (Part 1)

Editor: Kang Yan Reviewer: Yang Pengbin

(Speaker: Li Lingling, female, member of the Communist Party of China, deputy director of the Preventive Health Care Department of Yinchuan Stomatological Hospital, propaganda committee member of the Second Party Branch of the Oral Department of Yinchuan Stomatological Hospital, attending physician, young member of the Oral Preventive Medicine Professional Committee of the Chinese Stomatological Association, has studied in the Preventive Health Care Department of Peking University Stomatological Hospital. I am mainly engaged in dental clinics, oral health education and comprehensive prevention and treatment of oral diseases. I have been engaged in oral health education for nearly 10 years, with a total of about 150,000 health education sessions, covering people throughout the life cycle. I am responsible for and participate in many oral public health projects such as: "Ningxia Children's Oral Disease Comprehensive Intervention Project", "FDI", "Ningxia Region Disabled Children's Oral Disease Comprehensive Intervention Project", "Healthy Oral Growth Project", "Western Region Disabled Children Oral Disease Prevention and Treatment Public Welfare Project", etc., and organize oral volunteer activities all year round. Won the honorary title of "Science Popularization Star" in the 2019 National Oral Health Science Popularization Speech Competition-Northwest Region Competition; won the honorary title of "Science Popularization Elite" in the national competition; and obtained the title of "Healthy Oral Promotion Ambassador" awarded by the China Dental Disease Prevention and Control Foundation; guided and planned a total of 7 popular science creations He has used free clinics such as theme days, WeChat public accounts, and news media to promote oral health education to the public. He has assisted the China Dental Disease Prevention and Control Foundation in promoting public welfare oral causes at the Shenzhen Charity Fair and guided the public on scientific toothbrushing methods; he participated in the "21-day Scientific Toothbrushing Training Camp" public welfare activity jointly sponsored by the Beijing Center for Disease Control and Prevention, Beijing Health Education Institute, and the China Dental Disease Prevention and Control Foundation in 2021, and was awarded a volunteer certificate. In the process of diagnosis and treatment in the department, the digital audio-visual education (digital multimedia all-in-one machine) model is implemented, and popular science creation is incorporated into clinical teaching work. Students are encouraged to collect information and create oral science works to improve their oral health education capabilities and tap the potential for creating oral science works. In 2021, he applied for and established the Chinese Stomatological Association's Oral Health Education Innovation and Shining Plan project "Observation on the Effect of IMB Model Combined with Continuous Oral Health Education in Oral Health Education for Pregnant Women" to explore new models for the promotion of oral health education for special populations. )

Hello, students and teachers. Today I am honored to share with you some issues about oral health of teenagers. First of all, I would like to ask, have any of you ever been to the hospital to see a dentist? And why did you go to the hospital to see a dentist? Have you ever encountered problems such as bleeding when brushing your teeth, toothache, or new teeth growing out but the deciduous teeth have not fallen out?

1. Basic structure of teeth

The shape of the teeth

In response to the above questions, let's learn about them together today. First, let's get familiar with the appearance and structure of each tooth. Look at this picture. This is a big tree. The reason why the big tree can grow luxuriantly is because it is deeply buried in fertile soil. Our teeth are like this big tree that grows firmly in the soil. The crown is like the trunk, and the root is like the root. The reason why the teeth are stable is that the root is deeply buried in our bones.

The structure of teeth

What we just saw was the appearance of teeth, so what is the internal structure of teeth like?

First of all, we can understand the structure of our teeth. The translucent milky white thing that we can see covering our teeth like a small hat is called enamel. It is the hardest tissue in our human body. Next to the enamel is the dentin, which is a major component of the tooth. In the center of the tooth is a cavity, and the tissue inside is called the pulp, commonly known as the "dental nerve", which contains nerves and blood vessels. The nerves can make the teeth feel cold and warm, and the blood vessels can provide nutrition for the tooth tissue. Once the outer shell of the tooth is damaged, the dental nerve inside will lose its strong protection, be stimulated and damaged, and our teeth will ache.

The neck of the crown is surrounded by a layer of pink tissue called gums. If we don't brush our teeth well, dirt will accumulate on the edge of the gums, causing the gums to become red, swollen, and inflamed, and sometimes bleeding and painful.

The alveolar bone mainly supports and fixes the teeth. Our teeth are deeply buried in the alveolar bone, which can make the teeth more stable. If the bacterial infection in the mouth spreads to the bones, the alveolar bone will become inflamed and absorbed, just like soil erosion around the roots of a tree. The roots of the teeth will gradually be exposed, and even the teeth will become loose and fall off.

How many sets of teeth does a person have in his lifetime?

We have just had a relatively detailed understanding of the appearance and structure of a single tooth, so now let’s get to know other teeth.

A person has two sets of teeth in his life, one set of deciduous teeth and one set of permanent teeth. We start to grow teeth about 6 months after birth. The teeth that grow at that time are called "deciduous teeth". They will all come out at about 2 and a half years old, a total of 20. The tooth germs of permanent teeth are located at the root of deciduous teeth. Around the age of six, permanent teeth gradually erupt and deciduous teeth are gradually replaced. Except for the third molars, permanent teeth will all come out around the age of 13 or 14. Some people do not have third molars, so 28 to 32 permanent teeth are considered normal.

Division of labor among teeth

Students, we just said that there are so many teeth in our mouths, so what are the differences in their appearance? How do they divide the work when we enjoy a delicious meal?

Classification of Teeth

In this picture, we see the teeth in our mouth. According to their different shapes and functions, permanent teeth can be divided into four categories: incisors, canines, premolars, and molars.

First, the incisors, which we usually call "front teeth", are located in the front of the mouth, two on each side, for a total of 8. Its main function is to cut food and cut food into pieces.

The second type is called canines, also called "tiger teeth", which are located at the corners of the mouth, one on each side, for a total of 4. They are relatively thick and can withstand greater force. Their main function is to penetrate and tear food.

The third type is called premolars, also called "bicuspids", located behind the "tiger teeth", two on each side, a total of 8. It usually has two cusps, the main function is to tear food, but also has a certain grinding function like the teeth behind.

The last type is called molars, which are located behind the "bicuspids". There are 8 to 12 teeth in total. The food bitten off by the incisors or torn off by the canines is transported to the molars by the tongue for grinding. There are many grooves on the surface of the molars, just like a millstone, which can grind food for easy digestion and absorption by the gastrointestinal tract. So teeth are a big family, and any one of them cannot be missing.

Functions of Teeth

Classmates, do you know what functions our teeth have?

Teeth not only help chew food and help with pronunciation, but also have a great impact on a person's appearance and mental state. Teeth and alveolar bones make our faces fuller, and when there are too many missing teeth, the whole face will appear older and thinner.

Common oral diseases

So what are the common oral diseases for us teenagers? Let's take a look.

(ii) Dental caries

What is dental caries?

What is dental caries? Dental caries: commonly known as "tooth decay", is a disease in which teeth are destroyed under the influence of multiple factors, mainly bacteria. Dental caries are divided into three stages according to the degree of destruction: shallow, medium and deep. The teacher has taught you about the structure of teeth before. The outermost white layer of teeth is called enamel. What is the slightly yellowish layer inside the enamel called? Yes, dentin. When dental caries damage is limited to the enamel, it is shallow dental caries. When dental caries damage reaches the shallow layer of dentin, it is medium dental caries. When dental caries damage reaches the middle or deep layer of dentin, it is deep dental caries.

Causes of dental caries

The four factors of dental caries:

(1) The first is the "bacterial" factor: it is an important factor in the occurrence of dental caries. Dental caries will not occur without bacterial infection.

(2) Food factors: Bacteria can use the sugar in food to produce acid, which can damage teeth and cause caries. Therefore, it makes sense to recommend that you eat less food with high sugar content.

(3) Dental factors: refers to the appearance of our own teeth. The shape and arrangement of teeth are directly related to the occurrence of caries. For example, the grooves on the chewing surface of molars and crowded teeth are prone to caries.

(4) Time factor: The occurrence of dental caries is a chronic process.

Dental caries is shallow at the beginning. If we do not check and treat it in time, it will gradually develop into medium and deep caries. If it continues to develop, it will reach the center of the tooth and cause inflammation of the pulp. In this case, it can cause pulpitis and apical periodontitis. If it is not treated in time, the lesion will continue to develop until the crown is completely destroyed.

Symptoms of dental caries

So, students, do you know what the symptoms of dental caries are?

When the caries is superficial, there is usually no pain or other discomfort, which is often easy to be ignored. When the caries is moderate, people begin to be sensitive to cold, hot, sour and sweet.

If you feel uncomfortable, you should take it seriously, as it is very likely that the caries has developed into moderate caries.

When the tooth decay is deep, you will be very sensitive to cold, hot, sour and sweet things, and you will not dare to eat these things. If the tooth decay continues to develop, and there is severe pain from cold or hot stimulation, and it will hurt even if you don’t touch the tooth, it means that it may have developed into pulpitis.

When we do not take treatment measures when pulpitis occurs, the bacteria further infect the root and spread to the alveolar bone, causing swelling and pain, fear of biting teeth, sometimes low fever, facial swelling and other symptoms. A small abscess will appear on the gums near the root, which we call apical periodontitis.

Dental caries can not only cause sensitivity to cold and heat, pain, and affect eating, but also affect the whole body. In fact, dental caries can reduce chewing efficiency, affect food digestion and absorption, and affect growth and development; dental caries can damage teeth, especially the front teeth, which can affect appearance; unsightly teeth can also cause psychological pressure; bacteria in dental cavities are also potential sources of infection for some systemic diseases. So students, we must remember that if we have dental caries, we must treat it in time.