Comparison of occlusal contacts with use of Hawley and clear overlay retainers

Following orthodontic treatment, an increase in the number of occlusal contacts is usually desired during retention. In this study, Hawley and clear overlay orthodontic retainers were compared relative to changes in the number of occlusal contacts. Occlusal contacts were quantified in 30 orthodontic patients at debonding, at retainer delivery, and after 3 months of retention. The paired t-test was applied to evaluate longitudinal changes in the number of and intensity of contacts. Results show that with the Hawley retainer there was a significant increase in occlusal contacts on posterior teeth and no change on anterior teeth. With the clear overlay retainer there was no significant change in either posterior or anterior contacts during retention. The retentive capacities of the two retainers differ: the Hawley retainer allows relative vertical movement (settling) of the posterior teeth while the clear overlay retainer holds teeth in their debanding position.