Teeth may become more yellow as you get older, especially when the tooth enamel wears away from chewing and after exposure to acids from food and drink. Teeth turn yellow as the enamel thins with age, but may become a greyish shade when mixed with food stains.

Here are some tips to help prevent yellow teeth:

1. Practice good oral hygiene: Brushing your teeth twice a day and flossing daily can help to remove surface stains and prevent the buildup of plaque and tartar that can contribute to yellowing of teeth.

2. Use a whitening toothpaste: Whitening toothpaste contains mild abrasives that can help to remove surface stains and make teeth appear brighter. Look for a toothpaste that has the Australian Dental Association (ADA) Seal of Acceptance so the toothpaste is not overly abrasive

3. Avoid foods and drinks that stain teeth: Coffee, tea, red wine, and other dark-coloured beverages can stain teeth over time. Acidic foods and drinks, like citrus fruits and soda, can also erode the enamel and make teeth appear more yellow.

4. Drink through a straw: Drinking through a straw can help to minimize contact between staining beverages and your teeth, reducing the likelihood of staining.

5. Quit smoking: Smoking and tobacco use can contribute to yellowing of teeth and can also increase the risk of oral cancer.

6. Visit your dentist regularly: Regular dental cleanings can help to remove surface stains and prevent the buildup of plaque and tartar that can contribute to yellowing of teeth. Your dentist can also provide professional teeth whitening treatments if desired.

7. Be careful if you have gastric reflux: Sometimes the stomach acids wash over tooth structure and erode it away causing it to become a yellow shade.

8. Protect against teeth grinding: Wear an occlusal splint if you are grinding or clenching your teeth, to prevent them from wearing away.

9. Whiten your teeth: A dental professional can get your teeth their whitest in a safe way, to maintain the health of your teeth.

Remember, some people are naturally more prone to yellowing of teeth than others, and aging can also cause teeth to become more yellow. However, by following these tips and practicing good oral hygiene, you can help to minimize the likelihood of yellowing teeth and maintain a bright, healthy smile.