This problem usually happens because of decay of the baby cuspid (not too common) or because of crowding of the permanent incisors (more common), in which the crowded incisors push out a baby cuspid on one side. This is damaging to the symmetrical development of the dental arch because the incisors then drift into the space of the missing baby cuspid, which blocks the path for the permanent cuspid to erupt, and also shifts the dental midline. This asymmetry of the dental arch is difficult to correct and requires braces and rubber bands in the front of the mouth.
The proper thing to do when one baby cuspid is lost early is either to regain the lost space immediately with partial braces, or to remove the baby cuspid on the other side of the mouth and then place a lingual arch retainer wire to prevent the incisors from tipping backward from the pressure of the lip.
If a midline shift has already occured, take the child immediately to an orthodontist
