Fixed vs Removable Retainers and How Long to Wear Them: What the Evidence Says

What the evidence found

1. The review included 47 randomised controlled trials with 4,377 participants: 8 compared removable with fixed retainers, 22 compared types of fixed retainer, 3 compared bonding materials and 16 compared types of removable retainer. Studies of aligners were excluded. 2. Without a phase of retention after successful treatment, teeth tend to relapse, that is, return to their initial position. Retention uses fixed or removable retainers. 3. Part-time clear plastic retainers in the lower arch allowed more relapse than multistrand fixed retainers in one study (0.92 mm on Little's Irregularity Index), which the review reported was not clinically significant. Removable retainers were more likely to cause discomfort, but had less retainer failure and better gum health in that study. 4. In one study, full-time clear plastic retainers in the lower arch gave no clinically significant stability benefit over fixed retainers. Participants with clear plastic retainers had better gum health but a higher risk of retainer failure. 5. Clear plastic and Hawley retainers gave similar stability in one study, but Hawley retainers had a lower risk of failure and were less comfortable at six months. 6. One study found no evidence of a difference in stability between part-time and full-time use of Hawley retainers. 7. Between types of fixed retainer, the differences in stability reported by single studies (CAD/CAM nitinol and fibre-reinforced composite versus conventional multistrand wire) were not clinically significant.

How good is the evidence?

The review judged the evidence to be low or very low certainty. Most comparisons and outcomes were evaluated in only one study, 28 of the 47 studies had a high risk of bias, and most measured outcomes after less than a year (the review focused on 12-month follow-up). The authors conclude that firm conclusions cannot be drawn about any one approach to retention over another, and call for high-quality studies that follow tooth stability for at least two years and measure how long retainers last, patient satisfaction, and side effects such as tooth decay and gum disease. This page restates that review only; its searches ran to April 2022.

Sources

Martin C, Littlewood SJ, Millett DT, Doubleday B, Bearn D, Worthington HV, Limones A. Retention procedures for stabilising tooth position after treatment with orthodontic braces. Cochrane Database of Systematic Reviews. 2023;(5):CD002283. doi:10.1002/14651858.CD002283.pub5 (https://doi.org/10.1002/14651858.CD002283.pub5)

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This page summarises published research for general information only. It is not a diagnosis, treatment plan, or substitute for advice from a registered dentist or orthodontist.