You cannot reverse a cavity with tooth paste ,you need to treat it by filling the cavity hole by GIC or tooth colour filling (composite ) . when you eat carbohydrates rich food , the bacteria that live in your mouth feeds to it and produces acid which over a period of time destroys the tooth enamel leading to tooth decay .
Few things can help you avoid cavities or increase the cavity . Avoid too much of soda, candy and baked goods with
sugar. Additionally, use raw honey and maple syrup . Too much of Sugar causes demineralisation of teeth and create dental decay. Avoid photic acid , they not only prevent you from absorbing minerals in your food, but it also leaches minerals out of your body, bones and teeth. Consume raw dairy and nutrient rich food .
Take care