Posttreatment stability in adult and adolescent orthodontic patients: a cast analysis.

Orthodontic treatment of adults differs in many ways from that of the conventional adolescent patient. Adults are essentially nongrowing and have lower turnover rates of alveolar bone. These and other factors may affect the posttreatment stability of adult dentitions. This study compared the stability of orthodontic outcomes in matched samples of adolescents (about 13 years of age) and adults (about 30 years old) at an average of 5 years out of treatment. Analysis disclosed few differences between age groups; both exhibited considerable stability. Regarding key treatment considerations--such as midline alignment, incisor overbite and overjet, incisor irregularity, and molar relationship--both groups changed to equivalent degrees (and very little on average). Although minor differences were found (eg, arch length decreased more in adults), treatment changes in this sample of adults were at least as stable as those in the adolescents for all clinically relevant variables.