Оглавление

Английский язык. English in dentistry : учебник для студентов стоматологических факультетов медицинских вузов / Под ред. Л.Ю. Берзеговой. - 2009. - 272 с.
Английский язык. English in dentistry : учебник для студентов стоматологических факультетов медицинских вузов / Под ред. Л.Ю. Берзеговой. - 2009. - 272 с.
LESSON 10. CROWNS AND BRIDGES. GRAMMAR: SEQUENCE OF TENSES. INFINITIVE CONSTRUCTIONS (REVISION)

LESSON 10. CROWNS AND BRIDGES. GRAMMAR: SEQUENCE OF TENSES. INFINITIVE CONSTRUCTIONS (REVISION)

Exercise 1. Learn to pronounce the following words and word combinations; translate them into Russian:

appearance, severely discoloured teeth, misaligned teeth, impression, alloy, porcelain, partial denture, caution, ensure.

Exercise 2. Learn the active vocabulary to the text:

to restore teeth восстанавливать зубы

to place a crown одеть коронку

an impression слепок

life-size model модель в натуральную величину

alloy сплав

temporary crown временная коронка

fixed partial denture несъемный частичный протез

removable partial denture съемный частичный протез

to take caution быть осторожным, принимать меры предосторожности

to avoid избегать

«try-in» appointment примерка

Exercise 3.Read and translate into Russian the following dental terms and their definitions:

1. Porcelain / Resin Inlay / Onlay - conservative and aesthetic restorations for posterior teeth.

2. Implants - used to replace teeth, where there are no teeth.

3. Bridges - used to replace missing teeth.

4. Dentures - full or partial replacement of missing teeth, also serve as cosmetic function for lip support and facial contour.

5. Bonding - a direct placement of a resin restorative material to reshape or rebuild the tooth. This work requires much artistic talent from a dentist to replicate the life-like appearance of a tooth.

6. Porcelain veneers - the most aesthetic restorative materials used to cover the facial surfaces of teeth.

7. Crowns - can be of three types: full cast metal, porcelain fused to metal, ceramic. The type of the crown depends on several factors which are decided by the dentist.

Exercise 4. Translate the following word combinations into Russian before reading the text:

in addition to, decayed or broken crowns, to reduce a tooth in size, to fit over, to construct a life-size model, to fabricate the actual crown, to wear a temporary crown, to mask the defects, to use a fixed partial denture (bridge), to take caution to avoid damage, to eat a balanced diet, to ensure the health of teeth, to avoid fracturing.

Exercise 5. Read and translate the text into Russian:

CROWNS AND BRIDGES

In addition to restoring teeth that are badly decayed or broken, crowns (caps) can improve one's appearance by correcting severely discoloured, chipped or misaligned teeth.

To place a crown, the dentist must prepare the tooth reducing it in size, so that a replacement crown can fit over the existing tooth.

Impressions of the teeth and surrounding areas are made, and life-size models constructed. Using these models the actual crown is fabricated.

Today most crowns are made from alloys. Sometimes these alloys are coated with a layer of porcelain for natural appearance.

The patient is given a temporary crown to wear while the permanent one is being constructed. After a «try-in» appointment any necessary changes are made and the crown is put into place.

When a single crown is not sufficient to mask the defects and the patient has enough natural teeth remaining, a fixed partial denture (bridge) can be used.

For some dental problems, for example, insufficient remaining teeth affected by periodontal disease, a removable partial denture may be recommended. Both fixed and removable partial dentures depend on the existing teeth for their support, and caution must be taken to avoid damage to these supporting teeth. Thorough brushing and flossing, eating a balanced diet, and visiting the dentist regularly will help to ensure the health of the remaining teeth. Moreover, some precautions are necessary to avoid fracturing the replaced teeth.

VOCABULARY EXERCISES

Exercise 1. Give the English equivalents to the following words and word combinations:

одеть коронку, обломанные зубы, сменная коронка, естественный вид, скрыть дефект, съемный протез, меры предосторожности, постоянный протез, избегать повреждений.

Exercise 2. Give the synonyms to the following words: a crown, a bridge, a neglected tooth, badly damaged, to place a crown, to construct, to cover the defects.

Exercise 3. Put in proper prepositions and give Russian equivalents of the word combinations: l. to reduce a tooth.........size

2. to improve appearance....correcting teeth

3. to fit a replacement crown....the existing tooth

4. to coat the alloys....a layer of porcelain

5. most crowns are made....alloys

Exercise 4. Fill in the gaps with the words from your active vocabulary given in the brackets below. Translate the sentences into Russian:

1. Most manufacturers now produce a guide which shows the с ... and proportions used in the m ... of their a ... t ... . These guides are a great help in making the с . choice for p . j . crowns.

2. The t ... с ... so formed may then be removed.

3. When cooled, the i . should be examined carefully to see that it is accurate.

4. If a t . is a . by caries, softened t . should first be r . and replaced by zinc oxyphosphate cement.

5. The a ... of a wellmatched porcelain r ... is very similar to that of a natural tooth.

6. The crown can be easily f . during the next visit.

(fitted, temporary crowns, porcelain, jacket, correct, manufacture, affected, tissues, colour, removed, artificial teeth, impressions, tooth, appearance, restorations)

Exercise 5. Read the text and choose the correct answer to the given questions.

PORCELAIN RESTORATIONS

Porcelain was first used by the Chinese as long as 1000 years ago, and in more recent times by artists in other countries. The ceramic industry is now a very large one and the use of porcelain for dental purposes is only one of its many applications.

The first artificial teeth were made of porcelain in 1815, and the jacket crown was introduced by Land in 1895.

Porcelain is composed of kaolin (aluminium silicate) feldspar, and quartz. When heated to the appropriate firing temperature feldspar fuses to glass and this cements together more refractive kaolin and quartz. Small quantities of sodium and potassium carbonate are used as fluxes and the colour is controlled by pigments consisting of various metallic salts.

Porcelain has been used for the making of artificial teeth for such a long time that its properties are well known to all dentists. As prepared for dental purposes its colour and translucency can be made to simulate very closely the colour and translucency of natural teeth.

Questions: 1 .What can porcelain be used for?

a) It can be used only for making artificial teeth.

b) It can be used for many purposes including dentistry.

c) It can be used for many purposes but not in dentistry.

2. When were the first artificial teeth introduced?

a) only this century

b) in 1895

c) in 1815

3. What happens when porcelain is heated to the appropriate firing temperature?

a) It burns down completely.

b) It breaks.

c) The feldspar fuses to glass.

4. What qualities of porcelain are important in dentistry?

a) It is expensive.

b) Its colour and translucency.

c) Its fragility.

5.How long has porcelain been used in dentistry?

a) It is absolutely new, it's not known to dentists.

b) It has been used for a long time.

c) It is not known.

GRAMMAR EXERCISES

Exercise 1. Translate the following sentences into Russian paying attention to the Passive Voice:

1. Impressions of the teeth and surrounding areas are made.

2. Life-size models are constructed.

3. These alloys are coated with a layer of porcelain.

4. The patient is given a temporary crown to wear.

5. After a «try-in» appointment any necessary changes are made.

6. For some dental problems a removable partial denture may be recommended.

7. Caution must be taken to avoid damage to the support teeth.

Exercise 2. Translate the following sentences into English:

1. Коронки помогают исправить зубы неправильной формы, с измененным цветом.

2. Необходимо сделать слепки зубов и окружающих тканей.

3. Большинство коронок изготавливают из сплавов.

4. Пока готовится постоянная коронка, больному фиксируется временная.

5. Если одиночно стоящей коронки недостаточно, чтобы скрыть дефекты, используется частичный (постоянный) несъемный протез-мост.

Exercise 3. Translate the sentences into Russian paying attention to the Sequence of Tenses.

1. The patient said he had felt no pain.

2. The authour made it clear that new dental materials had been developed.

3. During a check-up the girl was told that she had to consult an orthodontist.

4. The woman hoped that her tooth could be saved.

5. The dentist was sure that the patient needed root canal therapy.

6. The girl complained that the new drug made her feel worse.

7. On his lecture on Prosthodontics the professor said that new dental materials were being used widely.

8. She asked for her tooth x-ray but the nurse said it was not ready.

9. Her dental mechanic said that all necessary changes in the artificial crown would be made after a «try-in».

10. The patient was informed that the life-size model had not been constructed yet.

Exercise 4. Find the Complex Subject or the Complex Object in the following sentences. Translate the sentences into Russian:

1. Accurate models of both dental arches are known to be of first importance in deciding upon a proper course of treatment in any given case.

2. The oral surgeon expects the area to heal after the surgical management before long.

3. Porcelain jacket crowns seem to approach the esthetic qualities of the natural teeth more closely.

4. The patient felt the pain radiate over the jaw, the ear, and the head.

5. Porcelain jacket crowns are considered to be primarily indicated for interior teeth in both jaws including bicuspids.

6. Dentists recommend people to have their teeth examined regularly even when they have nothing to complain of.

7. The effectiveness of dental materials is sure to be determined by physical or chemical reactions of the atoms.

8. The dentist advised her to have two crowns and a bridge fitted on the front teeth to keep them safe.

9. The fixed partial denture is believed to play an important role in occlusal rehabilitation.

10. Don't let him eat cold or hot food after the operation on the gum.

Exercise 5. Translate the following text into Russian in written form using a dictionary:

JAWBONE IMPLANTS

The method of treatment with a jawbone anchored bridge gives a final result similar to a tooth replacement with bridges attached to the patient's own teeth. The principle of the technique used is that bridge connections of titanium (fixtures) are placed directly in the jawbone. This means that the titanium fixture is built into the bone through the healing ability of the bone tissue (osseointegration). The material titanium is harmless to human tissues and does not cause any rejection reactions. This forms a basis for permanent anchoring function. With this procedure and with careful oral hygiene the jawbone and gums can be kept in a healthy condition. For most persons treatment with a jawbone anchored bridge can be performed by utilising the remaining jawbone. The volume of jawbone can be roughly estimated by an X-ray examination.

SPEECH EXERCISES

Exercise 1. Answer the following questions to the text «Crowns and Bridges»:

1. What purpose are the crowns (caps) used for?

2. What manipulations should the dentist perform to place a crown over the

tooth?

3. What materials are most crowns made of?

4. What is used by a patient while the permanent crown is being constructed?

5. In what cases is a fixed partial denture used?

6. What denture may be recommended in case of insufficient remaining

teeth?

7. What will help a person to ensure the health of remaining teeth?

Exercise 2. Give the summary of the text «Crowns and Bridges» using the answers to the previous questions.

Exercise 3. Read and translate the text into Russian and answer the questions:

CAST METAL AND PORCELAIN INTRACORONAL RESTORATIONS

The modern cast restoration owes its development to an American dentist, Dr. William H. Taggart, who in 1907 described a technique to produce gold castings which fitted prepared teeth with precision. The technique he refined is known as the lost wax process and involves making a wax pattern of the restoration which is then invested in a freshly mixed refractory material contained in a metal casting ring. When the investment has set, the whole is heated to a high temperature, causing the wax to burn out, leaving a space. Molten metal or glass is forced into mould to form a replica of the original wax pattern.

Direct and indirect techniques are two methods by which cast metal restorations can be made. In the direct method the wax is inserted directly into the cavity and the pattern is carved in the mouth and then invested and cast. It is taken to the chairside after polishing but with the margins untouched. Final finishing of the margins is then carried out in the mouth. Where the restoration is simple this technique is quick, accurate and saves both time and expense. However, single cavities can be satisfactory restored with plastic materials and so direct cast restoration is used very little today because it requires two visits by the patient, and is therefore expensive in time.

In the indirect method an impression of the cavity and the surrounding area is made in the mouth. From this impression a model of the tooth, a die, is constructed. The wax pattern is formed upon this die, invested, and cast. It is fitted and finished on the die in the laboratory. Thus, only minimal adjustment should be required at the chairside, as the majority of the work has been carried out on accurate models in the optimum conditions of the laboratory. This is the technique of choice for all complex restorations.

Indications for restorations

Direct cast metal inlays can only reasonably be made for very small cavities. The strength of the cast metal has very little advantage and the cost of the procedure is very rarely justified.

The indirect technique allows a much greater range of preparation design and the most commonly made type of cast metal inlay is used to protect the cusps by covering the occlusal surface. These are called either

inlays with cuspal protection or onlays. The second most common indication for indirect inlays is as part of a bridge or other appliance replacing missing teeth.

The traditional material for inlays is gold. Pure gold is seldom if ever used as it is a very soft material. Other metals are added to improve the physical properties, and therefore the material used in a traditional «gold» inlay is in fact a gold alloy. In some cases alloys containing 60 per cent or more of gold are still used and these can reasonably be described as gold alloys. However, the high cost of gold has stimulated development and improvements in other alloys and a vast choice is now available to the clinician and technician. Some alloys which are used for intracoronal restorations contain only 20 per cent or so of gold and so it is misleading to describe these as «gold» alloys. Other alloys contain no gold at all but are based on a combination of other metals. This is why the term «cast metal» is used.

Porcelain inlays were used occasionally in the past but with the introduction of composite materials they fell into disuse. However, a new generation of materials and techniques has been developed in the last few years and there has been a resurgence in the interest in porcelain inlays. Porcelain inlays or onlays are more natural in appearance than cast metal inlays and are more abrasion-resistant than composite. Therefore they may be appropriate in the occlusal surfaces of posterior teeth when large restorations are needed and appearance is important. They may be used in the buccal surfaces of visible anterior and posterior teeth when abrasion is a problem.

Porcelain veneers may give a very durable and unchanging appearance, and although tooth preparation is necessary, they are more conservative of tooth tissue than a conventional complete crown.

Porcelain inlays and veneers are made by one of two completely different techniques. In the first technique, the impression of the tooth is cast in a refractory material which can be heated to very high temperatures without damage. Porcelain powder is mixed to a paste with a liquid and placed into the inlay cavity or onto the labial surface of this refractory model and then fired in a furnace until the particles of porcelain fuse together. The process is repeated a number of times until the restoration is built to the required contour and colour.

The second method is to cast an ingot of castable glass into a mould made by the lost wax technique. This glass restoration is then treated in a ceramming furnace which converts the material to a ceramic which is then surface stained and fired to change its appearance.

Vocabulary to the text

cast оттиск, модель; отливать

precision точность

wax воск

refine совершенствовать, улучшать

molten расплавленный, жидкий

mould форма (для отливки искусственного зуба)

replica реплика, отпечаток

carve вырезать, резать

finishing полировка

accurate точный

ingot слиток

die (зуботехнический) штамп

adjustment корректировка

furnace горн, печь

misleading вводящий в заблуждение, обманчивый

resurgence возрождение, воскрешение

abrasion абразия, истирание

Questions to be answered:

1. What technique was described by Dr. W. H. Taggart?

2. What two techniques are used to make cast metal restorations?

3. Why is the term «cast metal» used?

4. What two techniques are used to make porcelain inlays and veneers?

5. Describe the indications for direct and indirect cast metal inlays.

6. Describe the indications for porcelain inlays or onlays.

Exercise 4. Select the facts in the text to support the following statements:

1. An American dentist described a technique to produce gold castings.

2. Direct cast metal inlays can only reasonably be made for very small cavities.

3. Pure gold is seldom if ever used for inlays.

Exercise 5. Read and translate into Russian the following text and point out the advantages and disadvantages of cast metal and porcelain restorations.

ADVANTAGES AND DISADVANTAGES

OF CAST METAL AND PORCELAIN RESTORATIONS

Cast metal is stronger in thin sections than amalgam, composite, or glass ionomer cement, and it has a greater ability to resist tensile forces. Thus, it is the material of choice to protect weakened cusps. It is also ideally suited for extracoronal veneer restorations such as onlays and complete and partial crowns.

In contrast, porcelain has high compressive strength but low tensile strength.This means that it is relatively brittle in thin sections, at least until it is bonded to the tooth and supported by it.

Cast metal and porcelain are at least as resistant to abrasion as enamel, and there has been some concern that porcelain is more resistant so that if a porcelain restoration is opposed by a natural tooth, the natural tooth may wear down more rapidly.

At one time, when the choice of restorative material was amalgam, gold, or silicate, gold was frequently preferred for aesthetic reasons as it was more attractive than amalgam and did not deteriorate like silicate. Also, in many societies it was regarded as a status symbol to have gold visible in the front or to the side of the mouth. Now relatively few patients ask for visible gold restorations.

Porcelain, in contrast can have a very natural appearance which is very durable compared with composite and glass ionomer which sometimes discolour or develop stained margins.

Cast metal is very versatile material. The indirect technique allows it to be shaped accurately in the laboratory to restore occlusal and axial contours and contact areas. These alloys are almost unchallenged as the materials of choice for bridgework.

Cost is the major disadvantage of cast metal and porcelain restorations. The reason for the high cost is the amount of time that they take compared with plastic restorations. There is always a laboratory stage and a minimum of two clinical appointments is necessary.

Notes:

tensile strength предел прочности при растяжении

brittle хрупкий, ломкий

deteriorate разрушаться

versatile универсальный

Exercise 6. Read the text and answer the questions below.

ADULT ORTHODONTICS

Although crowns and bridges may work wonders for some patients, such procedures won't help those with protruding or crowded teeth. Orthodontic treatment is the answer here.

Many adults seek care simply because they want a more attractive smile. However, orthodontic problems affect more than just a person's appearance. Crooked, crowded or protruding teeth are harder to clean, and the consequence could be more tooth decay or periodontal disease. If chewing is dif-

ficult because teeth are not properly aligned, there is a tendency to choose softer foods, often at the expense of nutrition. Misaligned teeth can also create tension and pain in the jaw joints because of the extra stress placed on chewing muscles. They can cause abnormal wear of teeth and lead to emotional problems due to their effect on speech and unattractive appearance.

Questions to be answered:

1. Do crowns and bridges work wonders for patients in all cases?

2. Why do many adults seek orthodontic care?

3. Do orthodontic problems affect only appearance of the patient?

4. What could the consequence of crooked, crowded or protruding teeth be?

5. What teeth can create tension and pain in the jaw joints?

6. What abnormalities do misaligned teeth cause?

Exercise 7. Translate the text «Impressions» into Russian and say which statements given below are true and which are false. Correct the false ones using the sentences from the text:

1. There are three groups of elastomeric impression materials.

2. The occlusal surface of the teeth may be recorded with air bubbles.

3. An interocclusal record is always needed.

4. A special tray is recommended with several elastomeric impression materials.

5. Elastomeric impression materials are not hydrophobic.

6. Careful management of gingival tissues is the key to taking good impressions.

7. A heavier-viscosity material or putty mix is syringed into the preparation and around the tooth.

8. A low-viscosity material is placed in the impression tray.

9. The impression is supported while it sets and then removed from the mouth.

10. There is no need to examine in detail the impression of the prepared tooth.

IMPRESSIONS

An impression of the cavity and the full arch of teeth is taken in an elastomeric impression material. The dentist may choose to use one of three groups of these materials: the polysulphides, polyethers, or silicones.

An impression of the opposing arch is taken, usually in alginate. An important feature of this impression is that the occlusal surface of the teeth should be recorded without air bubbles so that the opposing models can be articulated accurately.

An interocclusal record will not be needed where there are sufficient occluding teeth. However, if there is any doubt about the occlusion, a suitable interocclusal record is taken in the intercuspal position.

A special tray is recommended with several elastomeric impression materials. The tray supports the material around the teeth.

The elastomeric impression materials are hydrophobic and so the prepared tooth surface must be dry. The tooth is isolated with cotton-wool rolls and a saliva ejector is placed in the mouth.

Careful management of the gingival tissues is the key to taking good impressions, since any gingival exudate or bleeding will prevent the material from flowing over the prepared tooth surface.

The impression materials are mixed thoroughly before taking the impression. The retraction cord is removed and a low-viscosity material is syringed into the preparation and around the tooth. A heavier-viscosity material or putty mix is placed in the impression tray and the tray is seated over the unset low-viscosity material. This helps to adapt it into all the areas of the preparation and into the gingival crevice. The impression is supported while it sets and then removed from the mouth.

The impression of the prepared tooth should be examined in detail to check that the entire margin is visible and that there are no voids caused by air bubbles.

Notes:

impression tray слепочная ложка

bubble пузырек

saliva ejector слюноотсос

exudate экссудат

syringe шприц; вводить с помощью шприца

putty mix смесь для слепков

gingival crevice десневая борозда

void пустота, вакуум

Exercise 8. Review the text to answer the following questions:

1. What materials are used for impressions of the cavity and full arch of the

teeth?

2. Why is it important to record the occlusal surface of the teeth without air bubbles?

3. In what case is it not necessary to take an interocclusal record?

4. Why do dentists use an impression tray?

5. What is the key to taking good impressions?

6. What material is syringed into the preparation and around the tooth?

7. What material is placed in the impression tray?

8. Why should the impression of the prepared tooth be examined in detail?

Английский язык. English in dentistry : учебник для студентов стоматологических факультетов медицинских вузов / Под ред. Л.Ю. Берзеговой. - 2009. - 272 с.

LUXDETERMINATION 2010-2013