Dental hygienists use many types of tools to do their job. They clean and polish teeth with both hand and powered tools, as well as ultrasonic devices. In some cases, they remove stains with an air polishing device, which sprays a combination of air, water, and baking soda. They polish teeth with a powered tool that works like an automatic toothbrush. Hygienists use x-ray machines to take pictures to check for tooth or jaw problems.