At a community health event, a student uses a plaque-disclosing tablet before examining the teeth of a 15-year-old person. The tablet stains bacterial plaqu...
Question 1 Report
At a community health event, a student uses a plaque-disclosing tablet before examining the teeth of a 15-year-old person. The tablet stains bacterial plaque dark. Fig. 1 shows the upper surface of one molar after the person has rinsed their mouth. The dentist explains that bacteria in plaque use sugar from food and drinks. They produce acid, which can damage the hard outer layer of a tooth. The person normally drinks a sweetened sports drink slowly during afternoon training.
(a) Name the hard outer layer of the tooth that is damaged first by acid. [1]
(b) Describe where plaque is shown on the molar in Fig. 1. [2]
(c) Explain how frequent sipping of the sports drink can lead to a cavity in this tooth. [4]
(d) Give two changes the person could make to reduce the risk of tooth decay. [2]
(e) Use the information to explain why drinking the same volume of sports drink with one meal is less harmful to the teeth than sipping it over two hours. [2]
Answer Details
(a) The hard outer tooth layer is enamel. [1 mark]
(b) Plaque is shown in the grooves or pits on the chewing surface. [1 mark] It is also near the edge of the tooth at the gum line or on the side of the tooth. [1 mark]
(c) Sugar from the sports drink is available to bacteria in plaque. [1 mark] The bacteria produce acid. [1 mark] Acid dissolves, or demineralises, enamel. [1 mark] Frequent sipping keeps the mouth acidic for longer, so repeated enamel damage can develop into a cavity. [1 mark]
(d) Two acceptable changes include drinking sugary drinks less often, having sweet drinks only with meals, choosing water or unsweetened drinks, brushing twice daily with fluoride toothpaste, cleaning between teeth, or attending dental checks. [1 mark each, maximum 2 marks]
(e) Drinking the same volume with a meal causes one shorter period of acid production. [1 mark] Sipping over two hours causes repeated or prolonged acid attacks, leaving less time for enamel to recover or remineralise between them. [1 mark]
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