Dental Anatomy is a field of Anatomy devoted to the study of human tooth structure. Tooth development is a complex process during which teeth are formed from embryonic cells, grow and erupt in the mouth.

The teeth are a group of hard organs found in the oral cavity. We use teeth to masticate (or chew) food into tiny pieces. They also provide shape to the mouth and face and are important components in producing speech.

Each tooth is an organ consisting of three layers: the pulp, dentin, and enamel.

Teeth are classified into four major groups: incisors, canines, premolars and molars.

Incisors are chisel-shaped teeth found in the front of the mouth and have a flat apical surface for cutting food into smaller bits.

Canine teeth, also known as cuspids, are sharply pointed, cone-shaped teeth that are used for ripping tough material like meat. They flank the incisors on both sides.

Premolars (bicuspids) and molars are large, flat-surfaced teeth found in the back of the mouth. Peaks and valleys on the flat apical surface of premolars and molars are used for chewing and grinding food into tiny pieces.

Exercise 3.8. Use the letters to build the words fitting the context:

1) Dental Anatomy is a field of Anatomy devoted to the study of ______ ______structure (mhanu) (totoh).

2) The teeth are a group of hard organs found in the_____ _____ (raol) (vcaiyt).

3) We use teeth to _______ food into tiny pieces (tastimaec).

4) Each tooth is an organ consisting of three layers: the_____, _____, and enamel (ppul) (ndeint).

5) Teeth are classified into four major groups:________, canines, _______ and molars (iinsorcs) (pmrearols).

Exercise 3.9. Answer the questions to Text A and Text B:

1) What is the function of the teeth? 2) What parts is each tooth divided into? 3) What dental tissues are there in teeth? 4) How many roots do incisors have? 5) What is the hardest substance in the body? 6) In what tissue are the roots encased? 7) What is the function of the periodontal membrane? 8) What is Dental Anatomy? 9) What are the major groups of the teeth? 10) What are the main characteristics of incisors? 11) What are the main characteristics of cuspids? 12) What are the main characteristics of premolars and molars?

ODONTOGENESIS

Exercise 3.10. Study the active vocabulary for the lesson:

deciduous – временный

temporary – временный

succedaneous – замещающий

permanent – постоянный

upper – верхний

lower – нижний

dentition – прорезывание, рост зубов

denture – ряд зубов

intermediate – промежуточный

mesial line – срединная линия

central – центральный

lateral – боковой

eruption – прорезывание зубов

mandibular – нижнечелюстной

malnutrition – недоедание, неправильное питание

cause – вызывать, быть причиной

delayed – задержанный, замедленный

accommodate – размещать

occur – происходить, случаться

displace – вытеснять

predecessor –предшественник

crush – дробить, размельчать

pierce – протыкать, прокалывать

receive – получать

shear – резать

office – здесь, функция, место, предназначение

Exercise 3.11. Read text C and translate it into Russian:

Text C. Human Dentition

People have two sets of teeth, the deciduous (temporary) teeth, and the succedaneous (permanent) teeth.

The temporary teeth in humans are twenty in number: ten in the upper jaw and ten in the lower jaw, placed symmetrically on each side of the mesial line. Those teeth composing the deciduous set are four central incisors, four lateral incisors, four cuspids (canines), four first molars and four second molars.

The eruption of the primary teeth begins at about 6 months of age with the mandibular incisors. All primary teeth have usually erupted by the age of 2 years, although there is considerable individual variation, with some children not exhibiting their first teeth until they are over 1 year old. There do not appear to be any ethnic differences in the dates of eruption, but severe malnutrition may cause delayed eruption as well as seriously affecting other aspects of the child’s growth.

The usual order of appearance of the primary teeth in the mouth is central incisors, lateral incisors, first molars, canines, second molars.

Mandibular teeth usually erupt before maxillary teeth. As the child approaches the age of 5 years, spacing will appear between the primary teeth as a result of the jaw growth required to accommodate the developing permanent teeth.

Eruption of the mandibular permanent teeth tends to occur slightly ahead of the maxillary, by a few months. Only the permanent molars erupt without displacing a primary predecessor, and the first permanent molar appears at the age of 6 years.

There are normally thirty-two permanent teeth in the adult. In the permanent denture there are four central incisors, four lateral incisors, four cuspids (canines), four first premolars (bicuspids), four second premolars, four first molars, four second molars and four third molars.

The teeth having each one root are the permanent upper centrals, laterals, cuspids and second premolars. The first premolar has two roots; the molar teeth have each three roots. The lower centrals, laterals, cuspids, first and second premolars have each one root. The lower molars usually have two roots. The permanent centrals, laterals and cuspids have each one root. The upper molars have each three roots, while each of the lower molars has but two roots. The central and lateral incisors are used to incise or cut food. The teeth helping to pierce and shear food are the cuspids. The function of the premolars is intermediate between the cuspids and molars. The molars are used to crush or grind food.

The teeth have received their names according to their form or their office, thus, incisors – cutters, cuspidate – pointed, molars – grinders.

Exercise 3.12. Read and translate the following word combinations:

temporary teeth, central incisors, lateral incisors, cuspids, first molars, second molars, mesial line, permanent denture, premolar, upper and lower jaw.

Exercise 3.13 . Translate the words with the same root:

1) dent, to dent, dental, dentine, dentist, dentistry, dentition, denture;

2) to incise, incision, incisive, incisor, incised wound, incisive bone;

3) cusp, cuspid, cuspidal, cuspidate(d), bicuspid;

4) centre, central, centrals, centralization;

5) to erupt, eruption, eruptive.

Exercise 3.14. Answer the questions:

1) When does the eruption of the primary teeth begin? 2) Which is the usual order of appearance of the primary teeth in the mouth? 3) How many temporary teeth does a child have? 4) How many permanent teeth does an adult have? 5) What teeth compose the deciduous set? 6) What teeth compose the permanent teeth? 7) What teeth have one root? 8) What teeth have two or three roots? 9) What is the function of the teeth?

Exercise 3.15. Make special questions:

1) A tooth consists of two fundamental parts. 2) The roots are encased in cement. 3) Mandible teeth usually erupt before maxillary teeth. 4) The lower molars usually have two roots. 5) The molars are used to crush or grind food. 6) There are the teeth, the tongue and the salivary glands in the mouth. 7) The crown of each tooth is covered with dental enamel. 8) The brain is in the cranial cavity. 9) The students study Human Anatomy in the first two years. 10) We are carrying out the experiment in the laboratory now. 11) Humans have the deciduous and permanent teeth. 12) The temporary teeth in humans are twenty in number. 13) There are normally thirty-two permanent teeth in the adult. 14) The lower molars usually have two roots. 15) The upper molars have each three roots.

Exercise 3.16. Make special questions using the words in brackets:

1) Incisors have only one root. (How many) 2) The roots are encased in cement. (What) 3) The soft and hard palate and salivary glands are in the oral cavity. (Where) 4) The sublingual gland lies under the tongue. (What) 5) The saliva is sent to the mouth through the duct. (Where)

Exercise 3.17. Try to guess what teeth are mentioned. 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 years of age. They are four in number. They usually erupt at the age of 6 years.

Exercise 3.18. Choose any of the tooth structures (root, dentin, enamel) and describe the process of its development.

Exercise 3.19. Imagine that you are a pedodontist. Tell the child’s mother about the eruption of teeth and possible alterations or abnormalities. Try to explain the significant role of the process.

Additional Reading

Exercise 3.20. Read text 1 and translate it into Russian using the active vocabulary to it:

metabolic activity – обмен веществ, процесс метаболизма

solid substances – твердые вещества

to be bounded by – ограничиваться

to be divided into – подразделяться на

to dissolve – растворять

to recognize – различать, определять

to stimulate – стимулировать

vestibule – преддверие, передняя часть