Article Title and Bibliographic Information
The effects of fixed orthodontic retainers on periodontal health: A systematic review. Arn M, Dristas K, Pandis N, Kloukos D . Am J Orthod Dentofacial Orthop 2020;157:156-64.
Source of Funding
Information is not available and the authors did state any specific funding for this study and report no potential conflicts of interest.
Type of Study/Design
Four databases (Medline, EMBASE, Cochrane Oral Health Group's Trials Register and CENTRAL) were searched for studies focusing on the impact of fixed orthodontic retainers on periodontal health. In addition, literature that was not published was searched on ClinicalTrials.gov , the National Research Register, and ProQuest Dissertations & Theses. Randomized controlled trials (RCTs), controlled clinical trials, prospective and retrospective cohort studies, and cross-sectional studies of patients at any age who received any kind of fixed retainer after orthodontic treatment were included. Case reports, review articles, and animal studies were excluded.
Key Study Factor
Studies that measured periodontal health or disease outcomes of fixed orthodontic retainers without any limit on the observation period were included.
Main Outcome Measure
Periodontal measurements of any type during fixed retention were of interest. No specific primary or secondary periodontal clinical measurement outcomes were mentioned.
Three hundred and ninety-five studies were initially screened, and 29 studies (11 RCTs, 5 cohort, and 13 cross-sectional) fulfilled the criteria and were included in this systematic review. Of the 11 RCTs, the risk of bias was apparent, with only 5 studies reporting a proper randomization process, and the risk of bias ranged from small concern to high risk in the categories of measurement of outcomes and selection of reported results. The main results are reported as separate subheadings below;
Fixed retainer vs no retainer
There were 10 studies (1 RCT, 2 cohort, and 7 cross-sectional) that looked at comparing fixed orthodontic retainers with a control group (no retainer) and most of the studies did not report adverse outcomes on periodontal health, except 1 RCT and 2 cross-sectional studies that showed associations with poorer periodontal conditions. Some studies reported an increase in gingival inflammation in the lower lingual areas in patients without any retainers, since they were not seen as often for regular recalls. One study looking at marginal bone levels did not report any difference.
Fixed vs removable retainer
Out of the 5 RCTs, 2 prospective cohort, and 4 cross-sectional studies evaluated, only 2 studies reported more gingival inflammation in the presence of wired retainers (fixed), but no significant difference was reported in plaque levels, probing depths, and marginal gingival recession between the groups.