Dr. James Noble is staff orthodontist at Holland Bloorview Kids Rehabilitation Hospital in Toronto; he also maintains a private orthodontic practice in Toronto. Dr. Noble recommends:
Shawesh M, Bhatti B, Usmani T, Mandall N. Hawley retainers full- or part-time? A randomized clinical trial. Eur J Orthod. 2010;32(2):165-70.
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JCDA Clinical Pearl: It is clinically acceptable for orthodontic patients to wear Hawley retainers only at night.
This randomized clinical trial compared 2 orthodontic retention regimens in 67 patients: nighttime-only wear of an upper and lower Hawley retainer for 1 year vs. 6 months full-time wear followed by 6 months nighttime-only wear.
Study models were taken at the start and end of treatment and 1 year post-debond. Digital calipers were used to measure upper and lower labial segment irregularity (using Little’s irregularity index) and upper and lower labial segment crowding; t tests were used to evaluate differences between each group.
There were no statistically significant differences between the 2 retention regimens at 1 year post-debond for labial segment irregularity or crowding (p > 0.05).
Because both retention regimens were equally effective during the 1-year retention period, it would seem clinically acceptable to have patients wear retainers at nighttime only.
Reasons for recommending this article:
Retention protocols used by orthodontists can vary greatly, yet there is little evidence comparing post-treatment tooth movement and stability. This well-designed and executed study demonstrates that there is no difference in relapse with wearing Hawley retainers full time compared to nighttime only.
Wearing Hawley retainers during the day can be cumbersome for patients because speech is difficult, more effort is required to maintain oral hygiene, the labial bow of the Hawley is visible to others, and there is a greater chance that it will be lost. Based on the study results, it therefore seems reasonable to advise orthodontic patients to wear Hawley retainers at nighttime only. However, the authors warn clinicians not to extrapolate the findings of this study to vacuum-formed retainers.