Teeth decay when bacteria and plaque are allowed to build up in the mouth and eat away. Plaque that is not removed with thorough daily brushing and cleaning between teeth can eventually harden into calculus or tartar. Brushing removes plaque from the tooth surfaces. Brushing your teeth with fluoride toothpaste is your best bet when it comes to keeping your teeth in tip-top shape. Brush your teeth twice a day, with a soft-bristled brush. Brushing your teeth twice a day can save you hundreds of dollars–sometimes thousands–in dental work.