That article explains that although there can be variations from normal, there are certain patterns that most children follow in the loss of their primary teeth. The first step in any examination of children in the clinic is to take inventory of how many primary and permanent teeth they have. If they have more than they should for their age, my list of possible causes includes the following: an overall developmental delay, crowding, and impacted or missing permanent teeth. Before I offer an opinion however, I always look at a radiograph.
If the loss of primary teeth is slow but in the right sequence, I generally don’t worry until a child is two years behind. If the primary teeth “hang around” too long they can adversely affect the eruption path of the underlying permanent ones. For example, if a lower primary canine is still in place at age 10 or 11 (normally lost at 9), I’m not too concerned. I will probably recommend that it be removed at age 12 however. Another milestone that I consider is the eruption of the permanent second molars. Once they are in, any remaining primary teeth need to go.
There are other orthodontic reasons for removing primary teeth besides falling behind schedule. An obvious one is when a permanent tooth starts to come in adjacent to a primary one that isn’t loose. This commonly happens in the lower anterior when a permanent incisor erupts behind a primary one or in the upper canine area when a permanent canine erupts in front of the baby one (a “fang”). Removing the primary teeth in these instances is necessary but it does NOT correct the crowding that created the problem. It is important to realize that pulling BABY teeth never corrects crowding. It only “kicks the can down the road.” Eventually there will have to be expansion or extraction of permanent teeth if the final result is to be uncrowded.
Another time when primary teeth need to be removed is when doing so will change the eruption path of the associated permanent teeth. This is commonly done in the area of the upper canines and all second bicuspids. CBCT scans (3D x–rays) are excellent for helping me determine when removing primary teeth will help permanent ones come in better. Removing primary teeth at the right time can possibly save patients from more complicated treatment or even prevent surgery down the road.
Sometimes primary teeth must be removed by your dentist for other reasons (infection, trauma, etc.). When this happens, it is important that the space be maintained until the underlying permanent teeth are in place. If a “space maintainer” is not placed immediately and the adjacent teeth shift into the vacated area, the eruption of the corresponding permanent teeth may be affected or prevented.
Lastly, there are times when it is better to not remove primary teeth. Primary teeth should be restored and maintained if possible until the underlying permanent ones are ready to come in since they preserve the needed space. If the corresponding permanent teeth are missing however, you and your orthodontist will need to determine how to deal with the situation. If he or she decides that the space will eventually be closed, early removal of the primary tooth might be helpful. If you are going to eventually replace the missing permanent tooth with an implant, it may be best to preserve the primary one as long as possible to preserve the space and keep the surrounding gums and bone healthy.
As you can see, primary teeth serve an important function in the development of the permanent smile. Every child is unique and the decision whether or not to have primary teeth removed is one that you and your local orthodontist will have to make together.