Following the Whole Bite Club visit, students explore what causes tooth decay (dental caries). They will discover that decay is a kind of infection — germs in the mouth use the sugar in our food to make acid that can harm our teeth — and that the foods and drinks we choose affect how well our teeth are protected.
Learning intention
In this lesson, we will learn what causes tooth decay, and how our choices help protect our teeth.
Success criteria
I will know I am successful when I can:
Explain that tooth decay is caused by germs, sugar and time.
Explain that germs in our mouth use sugar to make acid that can harm our teeth.
Sort foods and drinks into everyday choices and sometimes choices.
Explain why water is the best drink for my teeth.
Suggest one choice I can make to protect my teeth.
Guiding questions
What is tooth decay (a cavity)?
What do you think causes a cavity?
Which foods and drinks help protect our teeth?
Vocabulary
tooth decay
cavity
germs
infection
acid
sugar
everyday foods
sometimes foods
water
plaque
protect
Differentiation
Support
Provide pre-cut picture cards of foods and drinks for students to sort into “everyday” and “sometimes.”
Use a simple picture sequence (germs plus sugar make acid, acid makes a cavity) for students to order.
Challenge
Students look at everyday packaged foods and drinks and find where sugar is listed.
Students design a “tooth-friendly” lunchbox and explain their choices.
Resources
Foundation – Year 2 Supporting Resource Pack
Picture cards or empty (clean) food and drink packaging
Simple diagram showing how a cavity forms [OHH to insert linked resource]
Short video about tooth decay and sugar [OHH to insert linked resource]
Where this comes from
The Whole Bite Club Teacher Guide
Oral Health Home · Held by Oral Health Home; not published online
The Foundation to Year 2 lessons themselves. Every lesson in this band is transcribed from the guide without paraphrase, so the guide is the source for the plan as well as for what it teaches.
That germs in the mouth feed on sugar and make acid, that the acid damages enamel, and that spit repairs the damage until the damage outruns the repair.
Why the lessons say tap water helps protect teeth in many places rather than everywhere: about 72 per cent of Queenslanders have a treated supply, and most councils have stopped treating.
National Health and Medical Research Council, Eat For Health · Opened 5 September 2026 · PDF
That the drinks and snacks this lesson calls sometimes choices are the discretionary ones, to be had only sometimes and in small amounts, and that whole fruit comes before juice, which is why juice is a sometimes drink rather than a bad one. The summary does not use the words everyday and sometimes for food; Health and Wellbeing Queensland, below, is the source for those.
Health and Wellbeing Queensland · Opened 5 September 2026
Everyday and sometimes as the words for food, and why the lessons use them: they describe what a food does without calling it good or bad, which is the whole point of the sorting activity.
The figures on the slides
Every figure this lesson puts on a screen, and where it came from. The presenter names each one at the foot of the slide that shows it.
Thirteen teaspoons is the sugar in a 600 mL bottle, from the Rethink your drink poster, Rethink Sugary Drink. Please note these are estimates only. That it is not for children is the position of the Oral Health Home clinicians, given on 7 September 2026.
Content
Introduction
Recall the Whole Bite Club visit, when the Oral Health Home team checked everyone’s teeth and talked about looking after the whole mouth. Explain that in this lesson we find out what causes tooth decay.
Ask the guiding question: What is tooth decay? Explain simply that tooth decay is when a tooth gets a hole in it, called a cavity.
Ask: What do you think causes a cavity? Record responses.
Body
What causes decay?
Explain that everyone’s mouth has tiny germs — some of these germs cause tooth decay.
Tell the simple story: the germs use the sugar in our food and drinks to make acid, and the acid can make holes (cavities) in our teeth. Decay happens when germs, sugar and time work on a tooth.
Explain that tooth decay is a kind of infection caused by germs — which is why keeping our teeth clean and keeping germs down helps protect them (this links to Lesson 4).
Everyday and sometimes
Introduce everyday foods (good to eat most of the time) and sometimes foods (okay now and then, but not every day).
As a class, sort a range of food and drink cards into everyday and sometimes. Discuss where sugary drinks and snacks belong, and why.
Water is the best drink
Discuss why water is the best drink for our teeth and bodies. In many places, our tap water also helps to protect our teeth.
Ask students to think about what they drink during the day and when water could be a good choice.
Reading health messages
Look together at health messages on food and drink packaging or posters. Discuss what the messages are telling us, and why (linking to health messages in our community).
Worksheet: What causes a cavity?
Students order the germs–sugar–acid–cavity sequence and/or sort everyday and sometimes foods, and complete the sentence: One choice I can make to protect my teeth is…
Conclusion
Review the key message: decay is caused by germs, sugar and time; water and everyday foods help protect our teeth; and keeping our teeth clean keeps germs down.
Students share one tooth-friendly choice they will try.
