Hawley or vacuum-formed retainers following orthodontic treatment?

DATA SOURCES: Cochrane Central Register of Controlled Trials (CENTRAL), Medline, Embase, ISI Web of Science, LILACS. In addition, Pro-Quest Dissertation and Thesis database and Pro-Quest Science Journals. Hand searches were also carried out in American Journal of Orthodontics and Dentofacial Orthopedics, Angle Orthodontist, European Journal of Orthodontics and Journal of Orthodontics.

STUDY SELECTION: Two reviewers independently selected studies, and randomised, quasi-randomised (RCTs) and controlled clinical trials (CCTs) were considered. Studies with at least six months follow-up were included.

DATA EXTRACTION AND SYNTHESIS: Data extraction and risk of bias assessment were carried out independently by two reviewers. A narrative summary was presented as a meta-analysis could not be performed.

RESULTS: Seven studies were included (five RCTs, two CCTs). Three were considered to be at low risk of bias, three at moderate risk and one at high risk. There was some evidence to suggest that no difference exists to distinguish between the HRs and VFRs with respect to changes in intercanine and intermolar widths after orthodontic retention. There was insufficient evidence to support the use of VFRs over HRs in relation to occlusal contacts, cost effectiveness, patient satisfaction and survival time.

CONCLUSIONS: This systematic review suggests that further high-quality RCTs regarding the differences between HRs and VFRs during orthodontic retention are necessary to determine which retainer is the better selection for orthodontists.