Listen to the tape-recording of the text and be ready to read the text aloud.

There are two sets of teeth: the deciduous or milk teeth and

permanent ones.

The deciduous teeth are 20 in number 5 on each side of the upper and the lower jaw, namely: 2 incisors, 1 canine, and 2 molars. There are 32 adult or permanent teeth: 8 on each side above and below namely: 2 incisors, 1 canine, 2 premolars, and 3 molars.

Each tooth is divided into a crown above the level of the gum, a neck surrounded by the gum, and a root or roots embedded in the jaw.

The crowns are chisel-shaped in incisor teeth, peg-shaped in canine teeth, have two tubercles in premolar teeth; have several tubercles in molar teeth. The upper teeth usually form a wider arch than the lower teeth and therefore overlap them.

Each root tapers to a point. The roots of the incisors, canine, premolar teeth are single. Each upper molar has three roots - two lateral and one medial, each lower molar has two roots: anterior and posterior.

The bulk of each tooth is composed of an exceedingly hard substance called dentine. The crown is covered with a thin layer of a still harder substance called enamel. The root is covered with a modified bone called cement

In the interior of each tooth there is a cavity called the pulp cavity, which contains vessels and nerves. The vessels and nerves enter the tooth through a foramen at the tip of each root.

The first deciduous tooth to erupt is one of the incisors and it should appear about six months after birth; all milk teeth should have appeared by the end of the second year. The first permanent tooth to erupt is one of the first molars and it should appear during the sixth year.

By the twelfth year all the permanent teeth should have erupted except the third molar, which appears at the time between 17 and 30.

EXERCISES

Ex. 1. Give English equivalents:

временные зубы, постоянные зубы, появляться, прорезываться, резцы, клыки, коронка, шейка, десна, корень, бугорок, отверстие, вещество дентин, цемент, эмаль, перекрывать.

Ex. 2. Choose the correct form of the verb:

1. The first permanent teeth (will appear, appeared, are appearing, appear) at six.

2. Each tooth (was divided, will be divided, is divided) into three parts: a crown, a neck, a root.

3. The roots of teeth (are embedded, were embedded, will be embedded) in the sockets of the jaw.

4. The upper teeth usually (are formed, form, will form) a wider arch therefore overlap the lower ones.

5. The bulk of each tooth (compose, is composed, will compose) of an exceedingly hard substance called dentine.

6. Many new stomatological clinics (are building, built, are being built) in our city now.

Ex. 3. Give the correct form of the Predicate:

1. The crown of a tooth (to be covered) with the enamel.

2. The deciduous teeth (to be replaced).

3. Your teeth (to be examined) by this dentist

4. Some medicine (to be given) by the nurse.

5. A bad tooth (to be extracted) by the surgeon.

Ex. 4. Listen to the tape-recording of the text "Teeth" and be ready to answer some questions.

TEETH

The teeth are implanted on the borders of the upper and lower jaw bones. The jaw bones are covered with a tissue known as the gum, which encircles the lower portion of each tooth. Two sets of teeth are developed during life. The first set is the milk or baby teeth. These develop shortly after the seventh month usually and are lost during childhood, when the second set of teeth or the permanent ones appear. The teeth differ from each other in form and hence in their usage. The front teeth, orthe incisors, are sharp and serve for cutting and tearing. The back teeth have large bases or crowns utilized in grinding and crushing the food.

A tooth consists of three parts - the crown, the neck and the root. The tooth itself is composed of a hard outer covering surrounding the central pulp cavity which contains a blood vessel and a nerve. The outer covering consists of a very firm hard substance, the enamel. This is the protective covering of the teeth. Beneath this is dentine, a softer and less resistant material than the enamel. When the enamel is broken the dentine soon suffers.

Ex. 6. Answer the following questions and check your answers:

1. Where are the teeth implanted on?

2. What tissue covers the jaw bones?

3. How many sets of teeth are there during life?

4. What are they?

5. What is the function of the incisors?

6. What is the function of the molars?

7. What does a tooth consist of?

8. What dental tissues do you know?

Lesson 7

THE MOUTH CAVITY

Wordbuilding

-sub - префикс, указывающий на положение ниже чего-либо
lingual - язычный sublingual - подъязычный

1.Guess the meanings and translate:

group - группа subgroup -

division - деление subdivision -

maxillary - челюстной submaxillary -

mandibular - нижнечелюстной submandibular -

cutaneous - кожный subcutaneous -

conscious - сознание subconscious -

normal -нормальный subnormal -

structure - структура substructure -

title - заголовок subtitle -

2. Try to remember these word combinations before reading the text:

to be subjected to - подвергаться

the prime organs - главные органы

alveolar ridges - альвеолярные отростки

insalivation - смачивание слюной

deglutition - глотание

to be invested - быть погруженным

to pour saliva - изливать слюну

to extend - простираться

dentition - ряд зубов

3. Look at the picture and show the accessory organs of the digestive system:

1 the gum

2 the tongue

3 the sublingual glands

4 the lips

5 the incisors

6 the canines

7 the premolars

8 the molars

9 the wisdom tooth

4. Read the text and be ready to answer some questions:

The mouth is an oval-shaped cavity situated at the beginning of the alimentary canal. In the mouth there are the teeth, tongue, and alveolar ridges, invested by the gum. The secretions of the parotid, submaxillary and sublingual glands are poured into the mouth cavity and in it the food is subjected to the processes of mastication and insalivation previous to deglutition. The teeth are the prime organs of mastication, and are implanted in the alveolar cavities.

A tooth is composed of four distinct structures:

1. The pulp occupying the chamber in the crown.

2. The dentine which constitutes the bulk of the organ.

3. The enamel which forms the protection of the crown.

4. The cementum which covers the root.

The teeth of the first dentition are termed deciduous or temporary teeth.

The temporary teeth are replaced by the permanent teeth. The anatomical divisions of a tooth are:

1. the crown or exposed part situated above the gum;

2. the root occupying the alveolar cavity of the socket;

3. the neck which is between the crown and the root.

The temporary teeth are twenty in number, ten in each jaw, namely: four incisors, two canines and four molars.

The permanent teeth are thirty two in number, sixteen to each jaw, namely: incisors - four, canines - two, premolars - four, molars - six. The third or last molar is called the wisdom tooth.

The incisors occupy the anterior central part of each maxillary arch. The function of this class of teeth is to cut the food.

The canine teeth are situated next to the incisors, two to each jaw. These teeth are for tearing the food.

The premolars, four to each jaw, are next to the canine teeth. They have two distinct cusps on their surfaces.

The molars occupy the posterior part of the alveolar arch and are six on each jaw. The function of the premolars and molars is to grind the food during mastication.

1. What sets of teeth do you know?

2. How many deciduous teeth are there on each jaw?

3. How many permanent teeth are there on each jaw?

4. Where is the mouth situated?

5. What classes of teeth are there?

EXERCISES

Ex. 1. Listen to the tape-recording of the text and prepare the fast reading of it.

Ex. 2. Give English equivalents:

овально-очерченная полость, секреция, жевание, ячейка, челюстная дуга, бугорок, разрезать пищу, первый ряд зубов, глотание, подвергаться, размалывать пищу.

1. The mouth cavity is situated ... the beginning ... the alimentary canal.

2. The tongue, teeth and the alveolar ridges are ... the mouth cavity.

3. The teeth are the prime organs ... mastication.

4. The enamel forms the covering and protection ... the crown.

5. The incisor teeth are used ... cutting the food.

6. The premolars have two distinct cusps ... their grinding surfaces.

Ex. 3 Give the correct forms of the verbs.

1. The patient (to examine) by the doctor tomorrow.

2. The teeth (to implant) in the jaw bones.

3. The roots of the upper wisdom tooth (to unite ) form one root.

4. We (to ask) by our professor to diagnose the case.

5. The food (to grind) during mastication by the teeth.

6. The secretion (to pour) by salivary glands.

Ex. .4 Translate the text without a dictionary:

The mouth is a part of the digestive system. There are the teeth, tongue, and salivary glands in the mouth. The cavity of the mouth is divided into two portions: the vestibule and the cavity proper. The vestibule of the mouth is a space bounded by the lips and cheeks. The lips and cheeks contain the mimic muscles. The oral cavity proper is bounded by the hard and soft palates. The hard palate separates the oral cavity from the nasal cavity. The mucous membrane covers the lips, and cheeks to the alveolar processes of the jaws. In the mouth the food is ground by the teeth and mixed with water, mucous and other secretions of the salivary glands. Saliva has the direct influence on the teeth and provides an optimal level of metabolic activity in the body. There are many salivary glands in the mouth; three principal pairs are recognized: the sublingual glands, submaxillary glands and parotids. The salivary glands regulate the water supply of the body.

Ex. 5. Answer the questions and check your answers:

1. What organs are there in the mouth cavity?

2. What does the mucous membrane cover?

3.What place do the molars (canines, incisors) occupy in the mouth cavity?

Lesson 8

DENTAL TISSUES

Wordbuilding

-ive - суффикс, образующий прилагательные со значением "способный на ч/л"

to form - образовывать formative - образовательный

to talk - разговаривать talkative - разговорчивый

1. Choose the right Russian equivalent:

EXPRESSIVE 1. Выраженный

2. выражаемый

3. выразительный

DECISIVE 1. решенный

2. решительный

3. решающий

CONNECTIVE 1. соединительный

2. соединенный

3. соединяемый

DIRECTIVE 1. направляющий

2. направляемый

3. направленный

2. Translate the international words and the words of Latin and Greek origin:

a function, to protect, substance, the gingiva, a process, compact, the characteristic form, implanted, friction, tactile.

3. You'll come across these word combinations in the text:
dental tissues - зубные ткани
supporting tissues - поддерживающие ткани
exposed tissues - незащищенные ткани

to wear - носить, изнашивать(ся)

to resemble - напоминать

beyond the border - выше границы (над границей)

amount - количество

to overlap - перекрывать

to fasten - прикреплять

suspensory mechanism - поддерживающий механизм

to give rise to smth. - дать начало ч.-л.