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

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.

Orthodontic Retainers—A Critical Review

“…Fixed retainers have been associated with a greater accumulation of dental plaque and calculus, and with minimally worse, albeit clinically unimportant, gingivitis in comparison with VFRs [97]. Moreover, patients using Hawley appliances may end up in an even better periodontal condition compared with those using VFRs [98]. Eroglu et al (2019) [99] found fixed and removable orthodontic retainers not statistically significantly different regarding the plaque index, the gingival index, bleeding on probing, and probing depth values.…”

Direct 3D-Printed Orthodontic Retainers. A Systematic Review

“…Comparing the removable appliances, HRs provide better settling of the occlusion compared with VFRs, and they also seem to be more durable in terms of breakage [ 7 , 48 , 56 , 57 ]. Bowen Li et al concluded in their systematic review that patients using HRs showed healthier periodontal condition than those using VFRs [ 58 ]. In contrast to this, VFRs are more aesthetic, do not interfere with speech and are therefore more acceptable to the patient [ 55 , 59 , 60 ].…”

Survey on retention procedures and use of thermoplastic retainers among orthodontists in Norway, Sweden, and Denmark

“…In terms of post-treatment stability, patient satisfaction, and survival time, there seems to be no evidence to support the use of thermoplastic retainers over Hawley retainers [19] . Furthermore, patients wearing thermoplastic retainers are shown to be more prone to gingival inflammation [20] . The increasing use of plastic materials in orthodontics may be alarming and adds to the growing concern about plastic pollution worldwide [26] .…”

“…In contrast, systematic reviews show insufficient evidence to support the use of thermoplastic retainers over Hawley retainers in terms of effectiveness, survival time, and patient satisfaction [17][18][19] . In addition, the most recent meta-analysis concludes that in the short term, thermoplastic retainers have more adverse effects on periodontal health than Hawley retainers [20] .…”