Comparison of Occlusal Contact Changes During Retention Between Hawley-Type Retainers and Other Retention Appliances: A Systematic Review

Abstract

Background: Achieving adequate and broad occlusal contacts following orthodontic treatment usually is performed during retention phase, and it ensures good intercuspation of posterior teeth and post-treatment stability. Objective: To investigate the changes in occlusal contacts with the use of Hawley-type retainers (Hawley’s and wrap around retainers) and compare them with other retention appliances. Methods: The search included articles that were published until December 2018 in three popular databases. Selection criteria comprised studies evaluating number and area of occlusal contact changes during or at the end of retention phase, following orthodontic treatment. After study retrieval and selection, data extraction and individual study risk of bias assessment was performed using the Cochrane Risk of Bias tool. Results: A total sum of eight studies reporting on outcome comparison between Hawley-type retainers with other retention appliances and untreated controls were selected. In all the eight studies, the risk of bias was unclear since blinding and random sequence generation was not reported. In all the eight reported studies, it was concluded that the number of occlusal contacts improved during retention period with Hawley type retainers, but when comparisons were done in between retainers, only two studies reported that Hawley-type retainers were better. Conclusion: This systematic review concludes that the number and area of occlusal contacts improved during retention with Hawley-type retainers. The overall quality of available literature is poor and unclear to support the conclusion that Hawley-type retainers are better than other existing retainers in improving occlusal contacts.

Occlusal Contact Surface Changes and Occlusal Force Distribution Between Vacuum-Formed Retainers and Other Retainers: A Systematic Review

“…Systematic reviews comparing the VFRs and HR retainers in terms of cost-effectiveness, patient satisfaction, survival time, and occlusal contacts concluded that there were very few differences between them and high-quality studies are needed to determine which is a better retainer [ 25 , 26 ]. A previous systematic review has reported that the NOCs improved in patients on HRs but there was no difference when compared to other retainers [ 27 ]. Conclusions from that review may not be valid since they included studies that reported only on NOCs but an assessment of area and distribution of occlusal contacts is more important.…”