Kids and toddlers have different teeth from the rest of us - from just gums to baby teeth, they don't look like perfectly-formed pearly whites right away. They're tiny, grow at odd angles, are uneven, and generally aren't even all there until your mid-teens. Give your sim kids & toddlers that chance by giving them some baby teeth or gums, both based on Pooklet's Teeth Kicker overlays.
Ankle Biters are just gums, whereas Chompers, as seen below, are a child's first teeth that are bound to fall out as they age.
These teeth are available for all ages, layerable, and found in the Blush section like other teeth overlays, because why not.
Download both teeth overlays here!