4. Dental crowns - (коронки)

PART I

PRE-TEXT ASSIGNMENTS

Exercise 1. Practice the pronunciation and memorize the words:

encase [in`keis] palladium [pə`leidiəm]

porcelain [`po:səlin] resin [`rezin]

ceramic [se`ræmik] alloy [`æloi]

drawback [`dro:bæk] prone [prəun]

withstand [wið`stæd] adjacent [ə`d3eisənt]

Exercise 2. Topic vocabulary:

encase цілком закривати resin пластмаса

porcelain порцеляна, фарфор alloy сплав

ceramic керамічний palladium паладій

drawback хиба, вада , недолік withstand витримувати

adjacent суміжний, прилеглий, сусідній

prone схильний

Exercise 3. Match the words and word combinations with their definitions :

1. alloy	any of a large number of synthetic materials that have polymeric structure
2. drawback	being near or close, esp having a common boundary; adjoining; contiguous
3. resin	resist
4. withstand	a disadvantage
5. adjacent	to place or enclose in or as if in a case
6. encase	a metallic material consisting of a mixture of two or more metals or of metallic elements with nonmetallic elements

Exercise 4. Give the Ukrainian equivalents of the following word combinations :

Severely discolored teeth, fully encase, at and above the gum line, severely worn down, to cover misshapened teeth, porcelain-fused-to-metal, withstand biting and chewing forces, the main drawback, out-of-sight molars, be color matched to the adjacent teeth, colour matched to the adjacent teeth, prone to fractures, a good choice for front teeth.

Exercise 5. Read the text :

A dental crown is a tooth-shaped "cap" that is placed over a tooth – covering the tooth to restore its shape , size and strength. The crowns, encase the entire visible part of a tooth . A dental crown may be needed in such situations: to protect a weak tooth from breaking or to hold together parts of a cracked tooth; to restore a broken tooth or a tooth that has been worn down; to cover and support a tooth with a large filling when there isn't a lot of tooth left; to hold a dental bridge in place; to cover misshapened or discoloured teeth; to cover a dental implant.

Permanent crowns can be made from metal, porcelain-fused-to-metal, resin, or ceramic. Metals used in crowns include gold alloy, other alloys (for example, palladium) or a base-metal alloy. Compared with other crown types, less tooth structure needs to be removed with metal crowns, and tooth wear to opposing teeth is kept to a minimum. Metal crowns withstand biting and chewing forces well and last the longest in terms of wear down. Metal crowns rarely chip or break. The metallic colour is the main drawback. Metal crowns are a good choice for out-of-sight molars. Porcelain-fused-to-metal dental crowns can be colour matched to the adjacent teeth (unlike the metallic ones). However, more wearing to the opposing teeth occurs with them compared with metal or resin crowns. The crown's porcelain part can also chip or break off. Next to all-ceramic crowns, porcelain-fused-to-metal crowns look most like normal teeth. However, sometimes the metal underlying the crown's porcelain can show through as a dark line, especially at the gum line if your gums recede. These crowns are good for front or back teeth. All-resin dental crowns are less expensive than other crown types. However, they wear down over time and are more prone to fractures.

All-ceramic or all-porcelain dental crowns provide the best natural colour match than any other crown type and are more suitable for people with metal allergies. However, they are not as strong as porcelain-fused-to-metal crowns and they wear down opposing teeth more than metal or resin crowns. All-ceramic crowns are a good choice for front teeth.

Exercise 6. Answer the following questions:

1. What is a dental crown?

2. In what cases can dental crowns be needed?

3. What can permanent crowns be made from?

4. What are the advantages of metal dental crowns?

5. What is the main drawback of dental crowns?

6. What are metal crowns good choice for?

7. What are the disadvantages of porcelain-fused-to-metal dental crowns?

8. What kind of crowns is most suitable for people with metal allergies?

9. What kind of crowns is the best choice for front teeth?

10. What is the cheapest type of dental crowns?

Exercise 7. Translate the following word combinations into English:

Металокерамічні коронки, стиратися з часом, держати зубний міст, повністю закривати усю видиму частину зуба, захищати від руйнування, порівнюючи з іншими видами коронок, головний недолік, рідко відколюются або ламаются, ясна відступають, менш дорогий ніж інші види коронок, хороший вибір для передніх зубів, забезпечити найбільш натуральний колір, більш придатні для людей чутливих до металів.

Exercise 8. Change the Active Voice into Passive.

1. People may need dental crowns in the following situations.

2. The dentist cements permanent dental crowns into place.

3. People choose all-ceramic crowns mainly for the front teeth.

4. The crown covered the cracked tooth.

5. The crown holds the dental bridge in place.

6. They make permanent crowns from all -metal, porcelain-fused-to-metal, all -resin, or all- ceramic.

Exercise 9. Insert the missing words into the gaps :

1. Permanent crowns … metal, porcelain-fused-to-metal, resin, or ceramic.

2. … provide the best natural colour match than any other crown type.

3. Metals used in crowns… gold alloy, other alloys (for example, palladium) or a base-metal alloy.

4. Metal crowns … and probably last the longest in terms of wear down.

5. Porcelain-fused-to-metal dental crowns … to the adjacent teeth (unlike the metallic crowns).

6. However, sometimes the metal underlying the crown's porcelain … as a dark line, especially at the gum line.

7. Metal crowns … chip or break.

8. … porcelain-fused-to-metal crowns look most like normal teeth.

Exercise10. Match the beginnings of the sentences with their endings:

1. The crown's porcelain portion	the entire visible portion of a tooth.
2. Metal crowns withstand biting and chewing forces well	to protect a weak tooth from breaking or to hold together parts of a cracked tooth; to restore a broken tooth or a tooth that has been worn down; to cover and support a tooth with a large filling when there isn't a lot of tooth left; to hold a dental bridge in place; to cover misshapened or discolored teeth; to cover a dental implant.
3. Compared with other crown types, less tooth structure needs to be removed	are less expensive than other crown types.
4. Next to all-ceramic crowns, porcelain-fused-to-metal crowns	for out-of-sight molars.
5.The crowns encase	and last the longest in terms of wear down.
6. A dental crown may be needed such situations:	with metal crowns, and tooth wear to opposing teeth is kept to a minimum.
7. All-resin dental crowns	can also chip or break off.
8. Metal crowns are a good choice	look most like normal teeth.

Exercise 11. Give a short description of all-metal, porcelain-fused-to-metal, all-resin and all-ceramic dental crowns.