| Purpose. This study will evaluate the long term post-retention changes of the mandibular teeth. Methods. A retrospective, longitudinal design was utilized to investigate the relationships between characteristics of post-treatment and post-retention records from treated orthodontic patients. Results. Small increases in crowding and irregularity occurred post-retention; the interrelationship between these two measures explained only 16% of the variation. Interrelationships existed between growth variables, as well as between inter-arch variables; however, these measures were not related to post-retention malalignment. Anterior arch perimeter, intercanine width, and arch form measures were interrelated and related to post-retention malalignment. Significant group differences were present with greater malalignment for extraction and post-treatment interproximal restorations groups. Conclusions. Orthodontic treatment is not inherently unstable. Mandibular irregularity progressively increases for teeth located further from the midline. The arch form becomes more square post-retention. A broader arch form is related to increased stability. Interproximal restorations are risk factors for post-retention malalignment. |
