1. The effects of soft drinks on teeth ACID ATTACK

2. What we will learn today: By the end of the lesson we will: Be able to describe tooth decay or erosion. Be able to explain the causes of tooth decay. Be able to suggest how tooth decay & erosion can be prevented.

3. Acid – a chemical with a bitter, sour taste that can dissolve some materials. Enamel – the hard outer covering of the teeth. Erosion – the process of a material being worn away. Neutralize – to stop something having an effect. PH Scale – a scale showing how acid or alkaline a substance is. Useful words:

4. What is erosion? Dental erosion is the loss of plaque free tooth by frequent acid attack. It can cause sensitivity to hot or cold or even cause the tips of teeth to chip away!

5. Where do we find acids? Acids are found in many foods & drinks. They add to the taste & also act as a preservative. Acids soften the enamel surface of the teeth & over time this can be chipped or worn away. Most drinks contain acids but some are more harmful to teeth than others.

6. Measuring acidity The level of acidity of a substance is measured by the PH scale from 0 - 14. A substance measuring 7 = neutral A substance measuring <7 = acid A substance measuring >7 = alkaline

7. Acid and teeth: A drink becomes harmful to teeth when the PH is below 5.5. Below 5.5, the enamel is softened and teeth are under attack.

8. What drinks are most harmful to teeth? Litmus Paper Test Activity: There are six different drinks to test. Can you decide which is most harmful & which is least harmful? Make your predictions on your activity sheet. Test the drinks using litmus paper & the PH scale. Compare the results with your predictions.

9. Type of DrinkAcidityType of DrinkAcidity Plain WaterPh 7.00Apple JuicePh 3.49 MilkPh 6.76Blackcurrant SquashPh 3.19 Fizzy WaterPh 4.72Fruit TeaPh 2.98-3.95 Diet ColaPh 4.61Low Calorie squashesPh 3.0-3.2 Orange JuicePh 3.84Still flavoured WaterPh 2.84 Lemon SquashPh 3.56ColaPh 2.63-2.49 Acidity of drinks: Your results will be similar to these…

10. Frequency of drinks (1): The amount you drink and how often affects the amount the acid attacks the enamel. The longer or more often the acid is in contact with your teeth, the longer it takes your saliva to neutralize the acid and return your mouth to a safe PH of 7.4

11. Frequency of drinks (2): Sipping an acidic drink throughout the day means your teeth are bathed in acid for longer than if you finish the drink in one go. It takes saliva between 30 minutes and 2 hours to neutralize an acid attack.

12. Diet Analysis: Diet Analysis Activity: From your diet sheet, mark on the clock face each time you had a drink. Colour in a 30 minute segment from the time you had an erosive drink Add up the amount of time each day that your teeth were under attack from acid. How well did you do?

13. How to reduce the risk of erosion (1): Frequent soft drinks should be avoided but if you do have one, drink it with a meal. Drink more water and milk or choose the least acidic drink. Use a straw when drinking an acidic drink. It reduces the contact between the acid and your teeth. Do not ‘swish’ the drink or hold it in your mouth.

14. How to reduce the risk of erosion (2): Chew sugar free gum – this increases the saliva and speeds up neutralization. Or rinse your mouth with water after an acid attack as the water washes the acid from the teeth. Avoid acidic drinks before bed or through the night as this is when the amount of saliva is at its lowest and damage could occur.

15. How to reduce the risk of erosion (3): Try to avoid brushing your teeth immediately after an acid attack. This is when the enamel is at its softest and you could wear some of the enamel away. If you must brush, rinse your mouth with water first.

16. What is dental erosion? Wearing away of enamel by acid attack What drinks cause erosion? Anything with a Ph below 5.5. What drinks are safe? Milk and water are the only safe drinks! How can erosion be prevented? Avoid acidic drinks Drink through a straw Don’t ‘swish’ drink around in your mouth Drink more water and milk What have we learnt?

17. Does anyone have any questions…?