What causes failure of fixed orthodontic retention? – systematic review and meta-analysis of clinical studies

Abstract

Background Orthodontic retention aims to maintain optimal teeth positions after active treatment. The stability is affected by numerous factors, including patients’ individual features, thus retention should be adjusted in the most optimal way. Bonding a retainer makes retention less dependent on patient’s compliance. Questions arise What wire or fiber splint type provides the best treatment stability? What materials should be used to bond the wire or fiber splint? Should be the bonding procedure be direct or indirect? The aim of the study is to assess and synthesize available controlled trials investigating failures of fixed retainers. Methods Literature searches of free text and MeSH terms were performed in Scopus, Web of Science, Embase and PubMed Central in order to find studies, referring to failures of fixed retention (12th February 2021). The keywords were: (“orthodontic retainers AND failure AND wire”). The framework of this systematic review according to PICO was: Population: orthodontic patients; Intervention: fixed orthodontic retainer bonding; Comparison: Different protocols of fixed orthodontic retention applied; Outcomes: failure rate, survival rate. Three different specific scales from the Cochrane Collaboration Handbook were used, according to each study type. Additionally, a meta-analysis was conducted to compare the effectiveness of retention using fiber reinforced composite and multistranded steel wire. Results The search identified 177 potential articles: 114 from PubMed, 41 from Scopus, 20 from Web of Science and 2 from Embase. After excluding studies inconsistent with selection criteria, 21 studies were included and subjected to qualitative analysis. The main outcome investigated was failure rate. This systematic review has some potential limitations due to the heterogeneity of design between included studies. Conclusions No retainer is proved to guarantee a perfect stability of dental alignment. The retainer should be bonded to all adherent teeth, preferably with additional use of bonding resin. No wire or fiber splint present superior characteristics concerning failure rate. Fiber reinforced composite retention is more sensitive to operator skills, and with imperfect bonding technique, failure rate is much higher. During the first 6 months after bonding retainer the patient should be under frequent control. The study protocol was registered in PROSPERO database with the number CRD42021233406.

Orthodontic Retention—Protocols and Materials—A Questionnaire Pilot Study among Polish Practitioners

“…The target population of this questionnaire was a group of specialists in orthodontics performing orthodontic treatment in Poland. Based on the latest systematic review-since no method nor choice of fixed retention has been scientifically proven to be superior to other materials, the questionnaire has been set to learn about clinical preferences of the orthodontic treatment providers [15], trying to find solutions based on the "wisdom of crowds", in this case, orthodontists offering commercial treatment. The survey was carried out in Polish language (Supplementary S1) within 3 months, from February to April 2021.…”

“…From the point of view of the scientific evidence, this approach seems optimal. The most frequently chosen answers indicated that clinicians know about the need of frequent controls during the first sixmonths period, which is scientifically valid [15]. A recent meta-analysis [15] showed that most failures of fixed retention occur within the first 6 months after bonding retainer, and, during that time the patient should be under frequent supervision.…”

“…The most frequently chosen answers indicated that clinicians know about the need of frequent controls during the first sixmonths period, which is scientifically valid [15]. A recent meta-analysis [15] showed that most failures of fixed retention occur within the first 6 months after bonding retainer, and, during that time the patient should be under frequent supervision. However, almost 30% of the clinicians declared recommending the first appointment with fixed retention after 3 months, and 17.3% after 6 months.…”

“…Since two answers were possible, indirect bonding was indicated by a small percentage of the respondents, as well. According to a recent systematic review [15], there is no difference concerning the frequency of failures referring to direct versus indirect bonding. However, indirect bonding saves chair time [39].…”

“…Bonding a fixed retainer makes the true goal of the retention phase-maintenance of treatment results-less dependent on patient's compliance [14], as well. The choice of material may influence the failure rate of the applied fixed retention [15]. Numerous studies can be found concerning the preferences of orthodontists referring to the retention protocol used or appliances used for removable retention [8][9][10][11][16][17][18][19].…”