RESUMEN
Maintaining the treatment results following orthodontic treatment is one of the most important aspects of the entire orthodontic treatment process. The purpose of the present study was to evaluate and compare the uses of Hawley and clear overlay orthodontic retainers relative to changes in overjet, overbite, intermolar width, intercanine width, and arch length measurements. These measurements were quantified in 48 adult patients at the time of insertion and after three months. The patients had pretreatment class I or class II div I relationship and were treated with preadjusted fixed appliance. Cases with open bite or crossbite were excluded from this study. Results showed that with Hawley retainer there was a significant change in the overbite measurements, while with clear overlay retainer there was no significant change during retention. The retentive capacities of the two retainers differ as Hawley retainer allows relative vertical movement of the posterior teeth, while clear overlay retainer holds teeth in their previous debanding position