Thorough cleaning and avoiding sugar are the best ways to prevent tooth decay. Third guarantee for strong biters: fluoride. Experts believe that tooth decay has decreased in children and adults in recent decades because everyone is consuming more fluoride. The mineral is contained in toothpaste and salt, but it is also available in higher concentrations as tablets, varnish or gel. Dentists also recommend fluoride for a relatively new dental disease in children: chalk teeth. They can be recognized by the whitish-yellowish spots in the tooth enamel; the teeth are soft and porous and crumbly like chalk. Chalking teeth only affect the permanent teeth, which begin to grow around the time they start school.