Sealants protect against cavities that can form in the natural tiny holes and cracks on the outside of teeth. Kids from about 6 to 12 benefit from having sealants painted and hardened onto the chewing surfaces of their back teeth, or molars. Adults can get sealants as well to protect teeth that don’t have fillings. Dentists or dental assistants put sealants on in an office visit, and it’s painless. They last around 2-4 years.