Dentists take care of people’s teeth and gums. They teach patients how to maintain their oral health by brushing, flossing, using fluoride, and eating a balanced diet. They also treat problems of the mouth such as cavities and gum disease. To become a dentist, you must graduate from dental school. Majoring in a science in college, such as biology, is also helpful. Following dental school, you must complete a one or two-year residency related to the specialty of dentistry you decide to pursue.