Text III. Stained teeth

Perfect snow-white smile is an ever-lasting dream. There are many reasons for your desire to make your teeth look whiter, including:

- the boost to your confidence and self-esteem that comes from a great smile,

- a younger appearance,

- a special event such as a wedding, job interview or class reunion,

- a desire to make a positive first impression on others, etc.

Just like we all have different hair and skin colour, people also have different tooth colour. Some teeth are more yellow than others, while others yellow with aging. Stained teeth (surface stains and internal discoloration) can be caused by a wide variety of factors:

- the natural aging process;

- using tobacco. Smoking can also lead to yellow or brown stains on teeth. The more you smoke, the darker your teeth become.

- Certain things you eat or drink can give your teeth a dull or yellow appearance. Drinking coffee, tea, colas or red wine and eating pigmented foods such as cherries and blueberries can evolve discolouring.

- Accumulation of plaque and tartar deposits.

- What’s more, certain drugs may cause discolouring of teeth as well. Some antibiotics or fluorine taken at an early age, when the teeth are developing, lead to the development of yellow, brown and grey stains later in life.

- Trauma to the teeth, using them as tools and

- general neglect will also make your smile less attractive.

Dentists advise: “ Break bad habits before they break your teeth”

Text IV. What effect does diet have on my oral health?

In addition to greatly affecting your overall health, proper nutrition is necessary for healthy teeth and gums. Eating a well-balanced diet gives your gum tissues and teeth the important nutrients and minerals they need to stay strong and resist infections. Firm, fibrous foods such as fruits and vegetables tend to help clean the teeth and tissues. Soft, sticky foods tend to remain on the grooves and between teeth, producing more plaque.

Each time you consume foods and drinks that contain sugars or starches, the bacteria in plaque produce acids that attack your teeth for 20 minutes or more. Certain foods (like potato chips) contribute to tooth decay while others (like cheese) may actually help resist it.

Tooth decay can occur when the acids in plaque attack your teeth. Plaque is the sticky, colourless film of bacteria that forms on everyone’s teeth daily. It coats exposed tooth surfaces and consists of millions of microscopic bacteria held together by various sticky substances.

After meals the bacteria in plaque produce acids that attack the tooth enamel. In case of repeated acid exposure, the enamel can break down and become decayed. Foods with carbohydrates and starches, especially those that stick to teeth, contribute to this acid production.

If left on teeth, plaque bacteria continue to grow and to produce acids that dissolve tooth enamel and create cavities. Untreated cavities enlarge and may cause pain even before they reach the nerve endings in teeth. Eventually they result in tooth loss. Plaque bacteria also produce toxins that attack gum tissue.

To reduce damage to your tooth enamel, limit the number or snacks and drinks. When you do snack, choose nutritious foods such as cheese, raw vegetables, plain yogurt or fruit.

Academy of General Dentistry. 2004 Yahoo! Inc.

Speaking

Choose one of the bad habits influencing oral health. Prove its negative effect on tooth structures.

Unit IX. Microbiology of the oral cavity

Lead-in

As you know, an essential step in caries development is the formation of plaque on the enamel surface. It is produced by certain microorganisms. But not only microbial flora will be highlighted in the Unit. You will also lean about normal flora of the mouth and its role in oral health. An association between different chronic diseases and oral microflora is being intensively studied nowadays by microbiologists. This Unit will provide a necessary insight into the microbiological origin of dental diseases.

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