There are plenty of toothpastes and rinses that you can buy that help you to build enamel coating on your teeth. Foods with sugars and such are not typically good for your teeth because when it is not washed out all the way, it begins to wear at your enamel and that is what gives you sensitive teeth. However, there are some foods that you can eat that help you to build that enamel back up without having to buy the expensive products at the store that can damage your mouth in other ways.
Teeth are like bones, in that they benefit from the intake of calcium. Dairy products are full of calcium and are good for you to eat when you have sensitive teeth. Things such as milk and yogurt are low in sugar and acidity which means that your teeth will not ache after eating them. The low acidity also helps to balance the pH in your mouth which keeps breath smelling good and your teeth feeling great!
Believe it or not, onions are good for your teeth. They have a compound in them that is anti-bacterial which helps to kill those nasty bacteria that make your gums and teeth ache. Make sure that you brush your teeth after, but it could end up being good for you!
Some other random foods include sesame seeds, fruits, green tea, and lots of water. Keep that in mind so that you can avoid sensitive teeth!