II. Работа над грамматикой – 40 мин Продолжение темы Continuous Tenses. Разница употребления времён Indefinite и Continuous. Выолнение упражнений раздела

III. Перевод текста со словарём. (40 мин) Направлено на формирование компетенции ок-6

Tooth structures formation

Dentinogenes is the name given to the origin and formation of dentin. Dentin is the 1^st mineralized tissue to appear in any developing tooth. It is composed of a fibrillar matrix, which mineralizes, and odontoblastic processes which remain unmineralized.

The 1^st dentin is formed at the incisal or cusp area of a tooth, and formation progresses in a rootward direction. Several cytoplasmic extensions of each odontoblast join to make a single dentinal process. The cells remain connected with their point of origin by the cytoplasmic extension, which are branched at their peripheral ends.

Dentin matrix mineralizes progressively. The newest nonmineralized dentin is called predentin. Dentin may be produced along the pulpal wall in a tooth of any age as long as the pulp is intact.

Amelogenesis is the name given to the process of enamel formation. The ameloblasts produce an organic matrix in which mineral salts later crystallize out of solution thereby making enamel a hard tissue. The formation of enamel is completed when submicroscopic crystals develop. Tooth enamel, being about 96% mineral substance, is the hardest of all body tissues.

As the root dentin starts to form, the already formed crown moves occlusally. If the tooth has a single root, the dentin wall encloses a single pulp canal. If the tooth is multirooted, the division of the pulp cavity into 2 pulp canals is apparent after the completion of the crown.

Root length is not complete until 1 or 4 years after the tooth emerges into the oral cavity. A newly emerged tooth has a short root and a large apical opening. As teeth become older, the root length is completed.

IV. Устная речь (40 мин). Направлено на формирование компетенции ок-6.

Задание 1. Try to guess what teeth are spoken about. Prove your point of view.

1. These teeth are four in number. They erupt from 7 to 9 months after birth.

2. This tooth is in the lower jaw. It has two roots. It erupts at the age of ten.

3. These teeth have each two roots. They are in the lower jaw. These teeth have no predecessors. Their function is to crush and grind food.

4. The function of these teeth is intermediate between the cuspids and molars. They erupt from 11 to 12.

5. These teeth are used to cut food. They are four in number. They usually erupt at the age of 6 years.

Задание 2. Choose any of the tooth structures (root, dentin, enamel) and describe the process of its development.

Задание 3. Imagine that you are a pedodontist. Tell a child’s mother about the eruption of teeth and possible alterations or abnormalities. Try to explain a significant role of the process.

V. Ознакомление с вариантом Лексико-грамматической итоговой работы №2 – 15 мин (см. Раздел Контрольные задания)