Fibres - Foods with fibre, such as fruits and vegetables have a detergent effect in your mouth. They also stimulate saliva flow, which, is the best natural defence against cavities and gum disease. About 20 minutes after you eat something containing sugars or starches, your saliva begins to neutralize the acids and enzymes attacking your teeth. Because saliva contains traces of calcium and phosphate, it also restores minerals to areas of teeth that have lost them from the bacterial acids. Fibres also help digest the food that we eat, preventing gastric regurgitation of stomach acids into the mouth & hence, protecting the teeth from damage, a phenomenon called ‘Tooth Erosion’.
Diary - Cheese, milk, plain yogurt, and other dairy products. Cheese is another saliva generator. The calcium in cheese, the calcium and phosphates in milk and other dairy products, help put back minerals your teeth that might have been lost due to consumption of other foods. Dairy products also replenish the ‘good bacteria’ pool in your mouth.
Foods with fluoride - Fluoridated drinking water, or any product you make with fluoridated water helps your teeth. This includes powdered juices (as long as they don't contain a lot of sugar) and dehydrated soups. Commercially prepared foods, such as poultry products, seafood, and powdered cereals, also can provide fluoride. However, excess of fluoride also harms the teeth by causing white to brown discolouration.
The Bad Food
Citrus –a rich source of vitamin C and other nutrients, are good for you in many ways, but not when it comes to your teeth. Grapefruit and lemon juice, in particular, are highly acidic and can erode tooth enamel over time. In a 2008 study that involved soaking pulled teeth in various citrus juices, those two caused the most damage. Orange juice caused the least. OJ is less acidic and many store-bought varieties are also fortified with teeth-friendly calcium and vitamin D. So our recommendation is to drink it, but brush and floss after every consumption.
Chewy candy - The stickier the candy, the worse it tends to be for your teeth. Extra-chewy candies—like caramels—stick to (and between) teeth for a long time, allowing the bacteria in our mouths to feast leisurely on the deposited sugar. And the bacteria in turn burns sugar to make acid, which dissolves the protective layer of tooth enamel and causes cavities.
Soda - It's no secret that drinking too many sugary sodas can breed cavities. What's less well-known is that the acids found in carbonated soft drinks appear to harm teeth even more than the sugar. And this holds true for sugar-free diet sodas as well, as they erode enamel if consumed in large doses. But if you have to drink soda, drink it during a meal, rather than sipping it throughout the day, that way the food will help neutralize the acid.