VI. Use the Complex Subject instead of a clause according to the model.

Model: It is well known that the first teeth are incisors.

The first teeth are known to be incisors.

1. It is known that teeth erupt after six months.

2. Centuries ago it was considered that dental caries was caused by a worm.

3. It was found that drinking tea without sugar reduces dental caries.

4. It is considered that his report on the use of new materials in dentistry was the best.

5. It is unlikely that he has failed the exam.

6. If he doesn’t look better after his teeth, it is likely that he can loose some.

7. It seems that he was administered a series of injections.

8. It seems that he is filling the patient’s tooth.

VII. Read and translate the text.

The Structure of the Mandible

The mandible lies below the anterior part of the cranium and is the skeleton of the lower part of the face. It has the body and a pair of flat, broad rami which stand up from the posterior part of the body. Each ramus is surmounted by two processes: The anterior is named the coronoid process and the posterior is the condyloid one. The condyloid process has an articular part called the neck.

The right and left halves of the body of the mandible are united together in the medial plane in front. Their junction is called the symphysis menti. The halves of the mandible are joined together by fibrous tissue at birth but they are fused together into one bone during the second year. Each half of the body of the mandible has an outer and an inner surface and an upper and a lower border. The surfaces slope so that the lower border makes a wider arch than the upper border.

The upper part is known to be called the alveolar part because it is occupied by a row of alveoli, those are the sockets for the teeth. On each side the sockets for the two incisors, the canine and two premolars are single but for the three molars they are double, for each mandibular molar has two roots – anterior and posterior. The lower border is known to be the base of the mandible. The outer surface is slightly convex but has a depression alongside the symphysis below the incisor teeth. The mental foramen is seen on the outer surface of the mandible. The inner surface is convex and concave at different parts. There is a shallow depression called the submandibular fossa.

The mandibular foramen leads into a canal which runs in the substance of the bone and carries the vessels and nerves for the teeth.

The mandible is the only bone of the face which has movement. The temporomandibular joint is known to make a wide range of mandibular motion. This joints consists of two joints on either side of the mandible which articulate with temporal bones on either side of the head. The mandible serves as the attachment of the elevator muscles which consist of the masseter, temporal and internal pterygoid muscles.

VIII. Answer the following questions.

1. What is the text about?

2. Where does the mandible lie?

3. What parts does the mandible consist of?

4. What is the structure of a mandibular ramus?

5. What is the junction of the two halves of the mandible called?

6. When are the halves of the mandible fused together into one bone?

7. Why is the upper part called the alveolar part?

8. Why can the sockets of the teeth be single or double?

9. Where is the mental foramen situated?

10. What is the function of the mandibular foramen?

11. The mandible is the only movable bone of the face, isn’t it/

12. What elevator muscles are attached to the mandible?