Postretention evaluation of stability and relapse--mandibular arches with generalized spacing.

Assessment of cases that had been out of retention a minimum of 10 years and had displayed generalized spacing of anterior teeth before treatment showed consistent reduction of arch length and intercanine width into adult years. Intercanine width constriction typically occurred while arch length decreased in every case, both width and length reduction being progressive with time. Crowding was minimal for the majority of cases; few demonstrated the severe crowding more typical of cases with pretreatment crowding.