The replacement of the baby teeth by the adult teeth occurs in two distinct phases: the first phase of replacement occurs between the ages of 5-7 years of age; the second phase between 11-14 years of age. During the first phase the permanent front teeth erupt in both the upper and lower jaws.
In the second phase, the side teeth (canines and bicuspids erupt). The two phases of eruption permit the child to transition smoothly from baby teeth to adult teeth. Crowding of the permanent teeth can occur in either or both phases of tooth replacement. A first phase of treatment is designed to promote a more successful second phase of eruption. If all of the teeth have enough room to erupt on the bony arches of the jaws during the first phase of tooth replacement, then the adolescent time period (11-14 years) is the ideal time to initiate treatment. The reason to seek treatment during adolescence is to correct the following:
- The width of the bite.
- The front to back relationships of the bite.
- Aligning the teeth.
During this time period, typical braces may be used to align the teeth. Rubber bands and the Herbst appliance may be selected to correct the bite relationship. The choice whether to use rubber bands or a Herbst appliance depends on the severity of the bite. Rubber bands are used to correct the bite by moving teeth. The Herbst appliance relocates the lower jaw and in doing so corrects the bite. Rubber bands only effect the teeth, the Herbst appliance moves teeth, bone, and the jaw. An added benefit of the Herbst appliance may be an improvement of the middle airway by positioning the tongue forward. This movement of the tongue may enlarge the airway.