Gingival condition associated with two types of orthodontic fixed retainers: a meta-analysis

Abstract

Background: The maintenance of gingival health around orthodontic fixed retainers (FRs) is difficult and different designs have been proposed. Objective: The goal of this systematic review was to analyse whether FR designs that allow unobstructed interproximal flossing, compared with the ones that do not, improve gingival parameters. Search methods: Detailed individual database search strategies for Cochrane Library, 'Latin' American and 'Caribbean' Health Sciences Literature, PubMed, Scopus, and Web of Science were developed. Grey literature was also considered. Selection criteria: Clinical trials and cross-sectional studies that compared two types of FRs (plain and waved) were included and evaluated. Data collection and analysis: Study selection, data extraction, and risk of bias (RoB) assessment were performed individually and in duplicate. The methodology quality was assessed using the MAStARI RoB tool. Results: Four studies met the inclusion criteria, and all presented moderate RoB. While two of those studies found a statistically significant difference in gingival parameters, the other two did not report differences. A meta-analysis was conducted based on two of the selected studies, which performed evaluations of plaque index (PI) and calculus index (CI). The results revealed no differences on PI between wave FR and plain FR of 0.46 (0.24 to 0.69) and no differences on CI of 0.12 (-0.10 to 0.33). Regarding comfort, no clear differences were identified. Conclusions: There is not enough scientific evidence to support or not an association between FR design and gingival health, flossing frequency, or patient comfort. Registration: PROSPERO - CRD42016030059.