Dental hygiene programs teach people to clean and protect patients' teeth. Students learn oral anatomy, hygiene theory, and cleaning techniques. They also study ways of identifying oral diseases and injuries. They learn how to instruct patients about flossing and caring for their teeth.

If the sight of your masked dental hygienist reminds you of a figure in a horror flick, think again. According to the U.S. Surgeon General, tooth decay is the single most chronic childhood disease. Moreover, studies have linked gum disease with diabetes, heart disease, and the birth of premature babies. So those instruments that your dental hygienist wields are for your protection and not your torture. In fact, dental hygienists are trained to help make their patients' experience at the dentist as pleasant as possible.

How do they do this? First, they learn how to clean and examine teeth for problems. They also learn how to apply materials that protect teeth from harmful buildup of a substance called plaque. That buildup causes the cavities that make fillings and root canals necessary. Dental hygienists are also trained to teach their patients how to take care of their own teeth.

About 300 colleges and universities offer certificates or associate degrees in dental hygiene. In addition, about 50 schools offer bachelor's degrees in dental hygiene. You can earn a bachelor's degree through either a degree completion program or an entry-level program. If research and education interest you, you can apply to a master's degree program at one of about eight schools.

You need a minimum of two years of full-time study after high school to earn a certificate or associate degree. Completing a bachelor's degree after an associate degree takes an additional two to three years. An entry-level bachelor's degree typically takes four years. After the bachelor's degree, a master's degree takes two years of additional study.