How many teeth should a six-year-old have?

By age 6, children generally have 20 teeth, which is the complete set of primary teeth. This is also the age that primary teeth begin to fall out to make room for the permanent ones, leaving empty spaces in some children's mouths, according to WebMD.

The bottom central incisors are typically the first to break through the gums at about 6 months of age, followed by the top central and lateral incisors. Between ages 6 and 12, children have a mixture of primary and permanent teeth in the mouth, with the canines and molars being the last of the primary teeth to fall out, according to WebMD.