The effects of fixed and removable orthodontic retainers: a systematic review.

Dalya Al-Moghrabi,Padhraig S Fleming,Nikolaos Pandis

doi:10.1186/s40510-016-0137-x

Dalya Al-Moghrabi, Padhraig S Fleming + Show 1 more

Open Access

https://doi.org/10.1186/s40510-016-0137-x

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Abstract

ObjectiveIn the view of the widespread acceptance of indefinite retention, it is important to determine the effects of fixed and removable orthodontic retainers on periodontal health, survival and failure rates of retainers, cost-effectiveness, and impact of orthodontic retainers on patient-reported outcomes.MethodsA comprehensive literature search was undertaken based on a defined electronic and gray literature search strategy (PROSPERO: CRD42015029169). The following databases were searched (up to October 2015); MEDLINE via OVID, PubMed, the Cochrane Central Register of Controlled Trials, LILACS, BBO, ClinicalTrials.gov, the National Research Register, and ProQuest Dissertation and Thesis database. Randomized and non-randomized controlled clinical trials, prospective cohort studies, and case series (minimum sample size of 20) with minimum follow-up periods of 6 months reporting periodontal health, survival and failure rates of retainers, cost-effectiveness, and impact of orthodontic retainers on patient-reported outcomes were identified. The Cochrane Collaboration’s Risk of Bias tool and Newcastle-Ottawa Scale were used to assess the quality of included trials.ResultsTwenty-four studies were identified, 18 randomized controlled trials and 6 prospective cohort studies. Of these, only 16 were deemed to be of high quality. Meta-analysis was unfeasible due to considerable clinical heterogeneity and variations in outcome measures. The mean failure risk for mandibular stainless steel fixed retainers bonded from canine to canine was 0.29 (95 % confidence interval [CI] 0.26, 0.33) and for those bonded to canines only was 0.25 (95 % CI: 0.16, 0.33). A meta-regression suggested that failure of fixed stainless steel mandibular retainers was not directly related to the period elapsed since placement (P = 0.938).ConclusionFurther well-designed prospective studies are needed to elucidate the benefits and potential harms associated with orthodontic retainers.

Highlights

Retention procedures are considered necessary to maintain the corrected position of teeth following orthodontic treatment and to mitigate against characteristic agerelated changes which, if unchecked, are known to culminate in mandibular anterior crowding [1]
Retention procedures are continually being refined with a recognition that existing protocols are infallible [2]
A recent Cochrane review exposed a lack of highquality evidence to favor one method of retention over another in terms of stability [3]. Given this absence of definitive evidence, retainer selection is often based on individual preference. This is evidenced by marked geographical variation with maxillary Hawley or vacuumformed retainers and mandibular fixed lingual retainers with full-time wear of removable retainers most popular in the USA [4, 5]

Summary

Introduction

Retention procedures are considered necessary to maintain the corrected position of teeth following orthodontic treatment and to mitigate against characteristic agerelated changes which, if unchecked, are known to culminate in mandibular anterior crowding [1]. Retention procedures are continually being refined with a recognition that existing protocols are infallible [2] Both fixed and removable retainers continue to be in vogue, adjunctive procedures including. A recent Cochrane review exposed a lack of highquality evidence to favor one method of retention over another in terms of stability [3]. Given this absence of definitive evidence, retainer selection is often based on individual preference. This is evidenced by marked geographical variation with maxillary Hawley or vacuumformed retainers and mandibular fixed lingual retainers with full-time wear of removable retainers most popular in the USA [4, 5]. In Australia and New Zealand, mandibular fixed and maxillary vacuum-formed retainers are shown to be the most prevalent combination [6], while a preference for the use of fixed retainers in both arches has been shown in the Netherlands [7]

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