Baby teeth matter: they hold space for adult teeth and set lifelong habits. The highest-risk window is when the first permanent molars erupt around age six, before children have the dexterity to clean them well on their own.
Let them start, then you finish. Fine motor control for effective brushing isn't there yet.
A rice-grain smear under three, a pea-sized amount after. Choose a flavor they will not fight.
A song, a timer, or a brush with a built-in one. Consistency beats intensity at this age.
By the first birthday or within six months of the first tooth appearing.
Yes — sealing the grooves of permanent molars cuts decay risk in those teeth dramatically.