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Meta-Analysis
. 2021 Jul 9;16(7):e0253968.
doi: 10.1371/journal.pone.0253968. eCollection 2021.

Assessment of the effect of vacuum-formed retainers and Hawley retainers on periodontal health: A systematic review and meta-analysis

Bowen Li  1 , Yifeng Xu  1 , Cailian Lu  1 , Zhenheng Wei  1 , Yongyue Li  1 , Jinghui Zhang  2
Affiliations
Meta-Analysis

Assessment of the effect of vacuum-formed retainers and Hawley retainers on periodontal health: A systematic review and meta-analysis

Bowen Li et al. PLoS One. .

Abstract

Background: Recently, increasing attention has been paid to the periodontal health of orthodontic patients in the maintenance stage in clinical practice. The focus of this meta-analysis was to compare the effects of vacuum-formed retainers (VFR) and Hawley retainers (HR) on periodontal health, in order to provide a reference for clinical selection.

Methods: From the establishment of the database until November 2020, a large number of databases were searched to find relevant randomized control trials, including the Cochrane Library databases, Embase, PubMed, Medline via Ovi, Web of Science, Scopus, Grey Literature in Europe, Google Scholar and CNKI. Related literature was manually searched and included in the analysis. Two researchers screened the literature according to relevant criteria. The size of the effect was determined using RevMan5.3 software, and the mean difference and 95% confidence intervals (CI) were used to estimate the results using a random effects model.

Results: This meta-analysis included six randomized controlled trials involving 304 patients. The results of the meta-analysis showed that there was no statistical difference in sulcus probing depth status between the VFR group and the HR group, including at 1, 3, and 6 months. Compared with the VFR group, the HR group showed a lower gingival index at 1 month (mean difference = 0.12, 95%CI: 0.06 to 0.19) and 3 months (mean difference = 0.11, 95%CI: 0.06 to 0.17), while there was no statistically significant difference at 6 months (mean difference = 0.10, 95%CI: -0.07 to 0.27). The plaque index of the HR group also showed a good state at 1 month (mean difference = 0.06, 95%CI: 0.01 to 0.12), 3 months (mean difference = 0.12, 95%CI: 0.08 to 0.16), and 6 months (mean difference = 0.19, 95%CI: 0.09 to 0.29). Subgroup analysis of PLI showed that when all teeth were measured, PLI status was lower in the HR group at 6 months (mean difference = 0.32, 95%CI: 0.18 to 0.46). PLI status was also low for the other teeth group (mean difference = 0.15, 95%CI: 0.08 to 0.22).

Conclusion: Our meta-analysis showed that patients using the Hawley retainer had better periodontal health compared with those using vacuum-formed retainers. However, more research is needed to look at the periodontal health of patients using these two retainers.

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Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. PRISMA 2009 flow diagram.
Fig 2
Fig 2. Summary of risk of bias.
Fig 3
Fig 3. Graph depicting the risk of bias assessment.
Fig 4
Fig 4. The status of GI index at 1, 3, and 6 months between the VFR group and the Hawley group.
Fig 5
Fig 5. The status of GI index at 6 months between the VFR group and the Hawley group after excluding a large heterogeneity study.
Fig 6
Fig 6. The status of PLI index at 1, 3, and 6 months between the VFR group and the Hawley group.
Fig 7
Fig 7. Subgroup of the status of PLI index at 6 months.
Fig 8
Fig 8. The status of SPD index at 1, 3, and 6 months between the VFR group and the Hawley group.
See this image and copyright information in PMC

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