Types of Teeth. Eruption

Read the following text

Active Vocabulary

Types of Teeth. Eruption

Unit 3

Fill in the gaps choosing the proper word in the box

Translate these word combinations

Match the words in (1-10) with their opposites (a-j)

Answer the following questions

1.What are the tooth main parts?

2. What part of the tooth is visible in the mouth?

3. Is the root below or above the tooth neck?

4. Is dentine the hardest substance of the tooth?

5. How many roots may a tooth have?

6. What structures are there around the tooth?

1. upper	a) soft
2. hard	b) inner
3. single	c) lower
4. outer	d) varying
5. below	e) wide
6. constant	f) multiple
7. blackish	g) visible
8. arrow	h) above
9. invisible	i) outside
10. inside	j) whitish

multiple roots; inner layer; varying density; below the neck; whitish substance; wide opening; lower jaw; hard outer layer; invisible part; inside the cavity.

a) pain, b) crown, c) cavity, d) blood, e) jaw, f) substance, g) contains, i) consists

1. Every tooth … of enamel, dentine, cementum and pulp.

2. The tooth … is the part visible above the gum line.

3. The root is the part hidden inside the ….

4. Enamel is the hardest … in the body.

5. Enamel is insensitive to ….

6. The pulp cavity contains … vessels, nerves and connective tissue.

7. Match the words (1-10) with the definitions (a –j)

1. the neck of the tooth	a) the part of the tooth hidden inside the jaw
2. the tooth root	b) part of the pulp cavity located in the root
3. the tooth apex	c) the junction of the crown and the root
4. the apical foramen	d) inner substance of the tooth, containing arteries, veins, and lymphatic and nerve tissue
5. enamel	e) the outer covering of the crown, the hardest substance in the body
6. cementum	f) the end of the root
7. dentine	g) a small opening at the end of the root
8. the dental pulp	h) the outer covering of the root, similar in structure to bone
9. the periodontal ligament	i) bone-like substance found beneath the enamel in the crown and beneath the cementum in the root
10. the pulp canal	j) the fibrous connective-tissue layer covering the cementum of a tooth and holding it in place in the jawbone

primary teeth	тимчасові зуби
fetus	плід
womb	утроба
gestation	вагітність
deciduous teeth	молочні зуби
incisor	різець
edge	край
canine	ікло
pointy	загострений, гострий
premolar	премоляр, малий кутній зуб
to grind	розтирати, розмелювати
eruption	прорізування зубів
teething	прорізування зубів
timing	терміни
to teethe	прорізування
to shed	втрачати (зуби)
permanent teeth	постійні зуби
to emerge	з’являтися, виходити
gap	щілина, проміжок

Each type of tooth is named for ease of identification. Incisors are the front teeth located in upper and lower jaws. Each incisor has a thin cutting edge. The upper and lower incisors come together like a pair of scissors to cut the food. Canines are the pointy teeth located on both sides of the incisors in the upper and lower jaws. They are used to tear food. Premolars have flat surfaces to crush food. Molar are larger than premolars. These teeth have broad, flat surfaces that grind food.

The deciduous teeth are the first set and are also known as milk or primary teeth. There are twenty of them, ten in each jaw, five on each side.

The term eruption refers to the tooth breaking through the gum line. In babied, tooth eruption is also called teething. The timing of tooth eruption differs from one child to another. For example, one child may cut their first tooth when only a few months old, while another may not teethe until they are 12 months old or more. While the timing may vary, the order of tooth eruption is generally the same. The two front teeth (central incisors) in the lower jaw are usually the first to erupt. This occurs somewhat between the ages of 6 to 10 months. The two front central incisors in the upper jaw erupt between ages of 8 and 12 months. The lateral incisors, which are the teeth on each side of the central incisors, erupt in both the upper and lower jaws between the ages of 10 to 16 months. The lower set tends to erupt before the upper. The first set of upper and lower molars erupt between the ages of 13 an 19 months. The second set of upper and lower molars erupts between the age of 25 and 33 months. Generally the average child has their full set of 20 primary teeth by the age of three.

Between the ages of about six and seven years, the primary teeth start to shed. The central and lateral incisors in the upper and lower jaws are usually the first to go. At about the same age the first permanent teeth erupt. These four molars (two in the upper jaw and two in the lower jaw) emerge behind the child’s existing primary teeth. Other permanent teeth, such as incisors and canines, erupt into the gaps gum left by shed primary teeth. The timing of eruption differs both for deciduous and permanent teeth. Like primary teeth for when the permanent teeth come through differs from one child to the next. Generally, the order of eruption and rough timeline for each type of permanent tooth include:

• First molars – between 6 and 7 ears old;

• Central incisors - between 6 and 8 ears old;

• Lateral incisors - between 7 and 8 ears old;

• Canine teeth - between 9 and 13 ears old;

• Premolars - between 9 and 13 ears old;

• Second molars - between 11 and 13 ears old;

• Third molars (wisdom teeth) - between ages of 17 and 21, if at all.

Дата добавления: 2015-03-29