The prevalence of the failure of fixed orthodontic bonded retainers: a systematic review and meta-analysis

Abstract

Objectives To systematically assess the scientific literature for the prevalence of failure rate of fixed orthodontic bonded retainer (FOBR). Method Randomized clinical trials (RCTs) and prospective non-RCTs involving participants who had FOBR fitted were included. The Cochrane Central Register of Controlled Trials, Web of science, MEDLINE, and EMBASE via OVID were searched from inception to January 2023. Risk of bias was assessed using the Cochrane RoB 2 and Newcastle–Ottawa tools. The main outcome was the failure rate of FOBRs. The secondary outcome was to identify factors that can influence the failure of FOBR. Meta-analyses and sensitivity analyses were undertaken using Revman, version5.4. A random-effects model was used. Quality assessment using Grading of Recommendations Assessment, Development, and Evaluation. Results Thirty-four studies (25 RCTs and 9 prospective clinical studies) (3484 participants) were included in this review. The overall failure rate of bonded retainers, after excluding high-risk studies, was 35.22% (95% confidence interval [CI] 27.46–42.98). The failure rate is increased with the duration of follow up; with short-term follow-up rate 24.18% (95% CI 20.16–28.21), medium-term follow up 40.09% (95% CI 30.92–49.26), and long-term follow up 53.85% (95% CI 40.31–67.39). There is a low level of evidence to suggest there is no statistically significant difference in the failure rate of fixed retainers using direct versus indirect bonding methods, using liquid resin versus without liquid resin, and fibre-reinforced composite retainers compared to multi-stranded stainless steel retainers. Discussion There is low-quality evidence to suggest that the failure rate of FOBR is relatively high. There is a need for high-quality, well-reported clinical studies to assess factors that can influence the failure rate of FOBR. Registration CRD42021190910.

Finite Element Analysis of Fixed Orthodontic Retainers

“…Retainer failure rates are relatively high, with 35.2% of conventional (bendable) fixed retainers failing [3], and these rates might even be higher in fixed retainers fabricated by computer-aided design/manufacturing (CAD/CAM) [4]. How differences in biomechanical behaviour affect the sufficiency of fixed retainers remains relatively unknown.…”

“…Herein, we used an FE model of a lower jaw anterior segment to investigate the effects of RS on the transmission of the force and distribution of stress along adhesive interfaces. We concentrated on the enamel-adhesive interface, because detachment in this interface is the most common failure [3]. The FE model was developed to understand why different retainers have different failure rates.…”