Lesson 1 Tooth decay

1.- Concepts of tooth decay and dental plaque.

Tooth decay:Caries is a disease of infectious origin that is characterized by the destruction of the tissues of the tooth and that is caused by the acids produced by the microorganisms that make up the dental plaque.

Dental plaque: It is a bacterial plaque formed by an organic layer of saliva proteins and bacteria. The main bacteria in the development of decay is Streptococcus mutans. In addition there are other microorganisms capable of producing large amounts of acid such as Lactobacillus.

2.- Causes of tooth decay.

The relationship between the intake of sugars and dental decay is demonstrated by historical evidence and clinical studies.

Until the 18th century, the prevalence of caries was low. In 1850 the consumption of refined sugars became popular, increasing the presence of decay in the population.

If the consumption of sugars is limited to the three main meals the effect of saliva can neutralize the bacterial attack and mineralize the dental enamel.

Therefore, the effect of sugars on oral health is an important thing. If sugars frequently enter the mouth, it is more likely that the acids produced by the bacterial plaque will attack the tooth enamel.

The foods that produce cavities are: sugary foods, carbonated drinks and foods rich in starch. 

Activity 1:View the video “Tooth Decay -- How it Happens and How to Avoid it” and answer the following questions. In pairs.

Questions:

1.- Where are the bacteria hiding? 

2.- What should you avoid between meals?

3.- When you will have toothache? 

4.- What can you do to avoid cavities? 

Activity 2: “The history of tooth decay”.

Part 1: Watch the subtitled video. “The history of tooth decay”.Individually work.

Part 2: Video quiz: “The history of tooth decay”. In small group (3-4 students).

Activity 3:Lesson 1 Vocabulary.Individually work.

Explain with your  owns words:  you can use one dictionary. 

• Enamel:
• Starch:
• Gum:
• Pulp area:
• Dental tissue:
• Junk food:
• Mouthwash:
• Dental plaque:

Activity 4:Lesson 1 Final Activity. In pairs.

Part 1: Watch the subtitled video “What causes cavities?”

Part 2: Interview. Roll playing. Oral activity.  Each will ask 3 questions about the video and answer the questions of partner.