Good dental hygiene is essential for children's oral health. Parents should begin taking care of their child's teeth as soon as the first tooth appears, and continue teaching good oral hygiene habits through adolescence. Here are some tips on how kids of different age groups can brush their teeth effectively:

Age 0-2: For babies and toddlers, parents should use a soft, damp cloth to clean their gums and any teeth that have erupted. Avoid using toothpaste until the child is old enough to spit it out, around age 2.

Age 2-5: At this age, children can begin using a small amount of fluoride toothpaste, about the size of a pea. They should be supervised while brushing to make sure they don't swallow the toothpaste. Parents should help brush their child's teeth until they are able to do it properly themselves, usually around age 6.

Age 6-8: Children should continue to use a pea-sized amount of toothpaste, and brush for at least two minutes twice a day. They should be taught to brush all surfaces of their teeth, including the front, back, and chewing surfaces.

Age 9-12: Children can begin using a regular-sized toothbrush and increase the amount of toothpaste to a small strip. They should continue brushing for two minutes twice a day and be encouraged to floss at least once a day.

Age 13-16: Teenagers should continue to brush twice a day for two minutes and floss daily. They should be encouraged to use mouthwash as well for extra protection against cavities and bad breath.

It's also important to replace toothbrushes every three to four months or when the bristles begin to fray. And children should visit the dentist every six months for a checkup and cleaning. By following these guidelines, children can develop good dental hygiene habits that will last a lifetime.