Primary tooth eruption and exfoliation  (falling out) and eruption of the permanent teeth varies from person to person - some children don't lose the last of their primary teeth until age 14 or 15.  And, occasionally, a permanent tooth will be congenitally missing, which prevents the primary (baby) tooth from loosening. This is one reason tooth development need to be checked by radiograph (x-ray)
There are twenty primary teeth, and thirty-two permanent teeth. The permanent molars do not replace primary teeth  - they erupt behind them, starting with the first molars at about age six.

If you have more questions, visit us our Kitchener Dentist Office in Doon South.

This information in provided by Doon South Dental, located in Kitchener, Ontario, Canada.  Call us at 1-519-748-4020 we look forward to connecting.