Tooth Care and Oral Health
FoundationBrush twice a day for two minutes with fluoride toothpaste, floss daily, eat less sugar, eat nothing after bedtime brushing, and have regular check-ups — then your teeth stay healthy for life.
- Germs in plaque turn sugar into acid, which eats into the enamel and causes cavities.
- Brush twice a day for two minutes with fluoride toothpaste: top teeth downwards, bottom teeth upwards, cleaning inside, outside and chewing surfaces.
- A brush cannot reach between the teeth, so floss once a day.
文體小知識：生活常識說明文把健康知識分點講清楚，跟着做就能養成保護牙齒的好習慣。
§Text Passage
1Every day when we eat, bits of food stay between the teeth and a colourless, sticky layer called plaque forms on them. The germs in plaque break down sugar and produce acid, which slowly eats into the enamel, the hardest outer layer of the tooth. In time a cavity forms. Enamel is the hardest substance in the human body, but once damaged by acid it never grows back, so protecting it is very important.
2A tooth has two parts: the crown, which shows above the gum, and the root, which is fixed in the jawbone. The crown is covered by enamel; inside that is the dentine, and at the centre is the pulp, full of blood vessels and nerves. Children have twenty baby teeth and start to lose them at about six years old. Adults have twenty-eight to thirty-two permanent teeth, which never grow back once lost.
3Good tooth care needs the right method: brush morning and night with fluoride toothpaste for at least two minutes each time; brush the top teeth downwards, the bottom teeth upwards, make circles on the chewing surfaces, and clean every inside and outside surface. The gaps between teeth cannot be reached by a brush, so clean them once a day with dental floss. Eat fewer sugary foods, and eat nothing after bedtime brushing so the teeth stay safe all night.
4At about six years old, the first permanent tooth grows behind the baby teeth. It is called the six-year-old molar. It does not replace any baby tooth, and it must serve us for the longest time, so it needs extra care. See the dentist every six months to a year, so that cavities are found early and small holes are filled while they are tiny — then our teeth can stay healthy for a lifetime.
1Summary 重點摘要
Brush twice a day for two minutes with fluoride toothpaste, floss daily, eat less sugar, eat nothing after bedtime brushing, and have regular check-ups — then your teeth stay healthy for life.
2Vocabulary cards Vocabulary
A colourless, sticky film of germs that builds up on teeth and causes decay.
The hardest substance in the body, covering the crown; once worn away it never grows back.
The layer under the enamel; it is softer and is reached once decay breaks through.
The centre of the tooth, full of blood vessels and nerves; it hurts a lot when infected.
A substance in toothpaste that strengthens enamel and helps prevent decay.
A thin string used to clean between teeth where a brush cannot reach.
The first permanent tooth, growing at about six behind the baby teeth, replacing none of them.
The pink flesh around the necks of the teeth; it bleeds easily when inflamed.
Treatment in which the dentist fills a cavity; small holes filled early can save the tooth.
3Step by step Steps
- Step 1: Learn the parts of a toothA tooth has a crown, the part we can see, and a root hidden under the gum. Think of a tooth as a boiled egg: the shell is like the hard enamel, the white is like the dentine, and the yolk is like the pulp in the middle. A cracked shell cannot mend itself, and neither can enamel worn away by acid, so once we know the parts, we understand why teeth need daily care. Children change their teeth from about six years old, and a lost permanent tooth never grows back, so protecting them early matters even more.
- Step 2: Brush twice a day for two minutes with fluoride toothpasteBrush every morning after getting up and every night before bed, for at least two minutes each time, using fluoride toothpaste, because fluoride makes enamel stronger. Divide the mouth into four areas — top right, top left, bottom right, bottom left — and brush each area for thirty seconds; together that is exactly two minutes. A little sand timer or clock helps you keep time. Hold the brush at about forty-five degrees to the gum line and use small, gentle strokes; too much force can hurt the gums.
- Step 3: Clean between the teeth with floss every dayBrushing cleans only the surfaces of the teeth; the gaps between them need dental floss. Pull out about thirty centimetres of floss, wind it around your middle fingers, slide it gently between two teeth, and scrape up and down against each tooth surface, using a clean part for each gap. The floss brings out bits of meat and vegetables, so decay germs have fewer places to hide. Beginners should move slowly and practise in front of a mirror a few times; a floss pick chosen with your parents can help too.
- Step 4: Cut down on sugary food and drinksSugar is the favourite food of decay germs, and the acid they make while breaking sugar down slowly eats into the enamel. One can of soft drink contains about nine teaspoons of sugar, around thirty-five grams — a surprising amount. Drink water when you are thirsty, keep sweet things for after meals, and the fewer times you eat them, the less acid attacks your teeth. Sticky sweets and biscuits stay on the teeth longer than other sweet foods and do even more harm, so eat them least of all.
- Step 5: Eat nothing after bedtime brushingAfter brushing at night, eat nothing more — not even milk or biscuits. During sleep there is less saliva to wash acid away; if bits of food are still between the teeth, germs make acid all night and decay happens fastest. Going straight to bed after brushing lets the teeth rest safely until morning. If you truly feel thirsty, a little water is enough before going straight to bed.
- Step 6: Have regular dental check-upsEven when the teeth do not hurt, see the dentist once or twice a year, for example in January and July. With a small mirror and a probe, the dentist can find tiny cavities we cannot see ourselves; filling them early is simple and hurts less. Regular check-ups stop small problems from growing serious. If you have questions, such as uneven teeth or bleeding gums, ask the dentist for advice at the same time.
4Diagrams Diagrams
5Worked example Example
Example: Shan brushes her teeth every day, but only once, in the morning, and she likes to drink a can of soft drink before bed. Explain how her habits harm her teeth, and suggest three improvements.
- She brushes only in the morning, so all the bits of food and plaque from the whole day stay in her mouth overnight; with less saliva during sleep, germs make acid all night and attack the teeth.
- Drinking a soft drink before bed leaves sugar between her teeth; with less saliva at night the acid is not washed away, so decay speeds up greatly.
- Improvement one: brush morning and night, at least two minutes each time, using fluoride toothpaste to make the enamel stronger.
- Improvement two: eat and drink nothing after bedtime brushing, and choose water instead of soft drinks, leaving less sugar in the mouth.
- Improvement three: floss every day and see the dentist every six months to a year, so tiny cavities are found and filled early.
- Answer: Shan's habits let acid attack her teeth all night, so decay is very likely. She should brush twice a day for two minutes, eat nothing after bedtime brushing, floss daily, and have regular check-ups, so her teeth stay healthy as she grows.
6Common mistakes Mistakes
7Quick check Quick check
Q1What is the hardest outer layer of a tooth called?
Q2Why must we not eat anything after brushing at bedtime?
Q3What is special about the six-year-old molar?
Q4What is the best tool for cleaning bits of food from between the teeth?
Q5How often should we have a dental check-up?
8Recap Recap
- Germs in plaque turn sugar into acid, which eats into the enamel and causes cavities.
- Brush twice a day for two minutes with fluoride toothpaste: top teeth downwards, bottom teeth upwards, cleaning inside, outside and chewing surfaces.
- A brush cannot reach between the teeth, so floss once a day.
- Eat fewer sugary foods and nothing after bedtime brushing.
- The six-year-old molar is the first permanent tooth; have a dental check-up every six months to a year.