Periodontal effects and survival rates of different mandibular retainers: comparison of bonding technique and wire thickness

Survival rates of mandibular fixed retainers: comparison of a tube-type retainer and conventional multistrand retainers : A prospective randomized clinical trial

OBJECTIVE

The purposes of this study were to evaluate the survival rate of a tube-type mandibular fixed retainer and compare it to conventional multistrand retainers.

MATERIALS AND METHODS

In all, 66 patients who had completed their orthodontic treatment were enrolled in this study. They were allocated randomly to a tube-type retainer group or a 0.020 multistrand fixed retainer group. In case of the tube-type retainer, a thermoactive 0.012 NiTi was placed into 6 mini-tubes passively bonded to the anterior teeth. The patients were recalled at 1, 3, 6, 12, and 24 months after retainer placement. During the 2‑year follow-up period, any first-time failure of retainers was recorded. Kaplan-Meier survival analysis and log-rank tests were used to compare the failure rates between the two types of retainers.

RESULTS

Of the 34 patients, 14 (41.2%) showed failure in the multistrand retainer group, whereas only 2 of 32 (6.3%) reported failure in the tube-type retainer group. There was a statistically significant difference in failure between the multistrand retainer and the tube-type retainer (log-rank test, P = 0.001). The hazard ratio was 11.937 (95% confidence interval 2.708-52.620; P = 0.005).

CONCLUSION

The tube-type retainer can be used with fewer concerns about recurrent retainer detachments during orthodontic retention.

The oral microbiota and periodontal health in orthodontic patients

The oral microbiota develops within the first 2 years of childhood and becomes distinct from the parents by 4 years-of-age. The oral microbiota plays an important role in the overall health/symbiosis of the individual. Deviations from the state of symbiosis leads to dysbiosis and an increased risk of pathogenicity. Deviations can occur not only from daily life activities but also from orthodontic interventions. Orthodontic appliances are formed from a variety of biomaterials. Once inserted, they serve as a breeding ground for microbial attachment, not only from new surface areas and crevices but also from material physicochemical interactions different than in the symbiotic state. Individuals undergoing orthodontic treatment show, compared with untreated people, qualitative and quantitative differences in activity within the oral microbiota, induced by increased retention of supra- and subgingival microbial plaque throughout the treatment period. These changes are at the root of the main undesirable effects, such as gingivitis, white spot lesions (WSL), and more severe caries lesions. Notably, the oral microbiota profile in the first weeks of orthodontic intervention might be a valuable indicator to predict and identify higher-risk individuals with respect to periodontal health and caries risk within an otherwise healthy population. Antimicrobial coatings have been used to dissuade microbes from adhering to the biomaterial; however, they disrupt the host microbiota, and several bacterial strains have become resistant. Smart biomaterials that can reduce the antimicrobial load preventing microbial adhesion to orthodontic appliances have shown promising results, but their complexity has kept many solutions from reaching the clinic. 3D printing technology provides opportunities for complex chemical syntheses to be performed uniformly, reducing the cost of producing smart biomaterials giving hope that they may reach the clinic in the near future. The purpose of this review is to emphasize the importance of the oral microbiota during orthodontic therapy and to use innovative technologies to better maintain its healthy balance during surgical procedures.

Keeping the teeth in line: Exploring the necessity of bonded retainers in orthodontics: A narrative review

In most recent studies, long-term retention after orthodontic treatment has been hypothesized that may be necessary to maintain the stability of the dentition and avoid post-treatment changes. The bonded fixed retainer is characterized by its clinical effectiveness, patient acceptance, and lack of patient complaints as compared with a removable retainer. An electronic database (such as PubMed, PubMed Central, Web of Science, Science Direct, Cochrane Library, Scopus, and ResearchGate) has been collected using specific keywords. Of the 152 articles, only randomized clinical trials that investigated different types of fixed retainers or compared fixed with removable retainers were illustrated in tables and included in this review. The present review has gone some way towards enhancing our understanding of the bonded fixed retainer, types, material, bonding methods, and how to improve its the success rate, besides the importance of new technology in fixed orthodontic retention.

Orthodontic retention: Rationale and periodontal implications

Post-treatment change in the form of true relapse and physiological and maturational effects is common following orthodontics. The unpredictable nature of these manifestations dictates a conservative, near-universal approach to retention. Both fixed and removable forms of retention are popular with the latter constrained by variable levels of adherence particularly in the medium- to long-term. Fixed retention may offer a more predictable means of preservation of orthodontic outcomes; however, this advantage is offset by the requirement for prolonged supervision and the potential for adverse changes including periodontal breakdown. Nevertheless, while examples of severe complications are common, a clear causal relationship between intact, passive retainers and periodontal issues does not appear to exist. Nevertheless, the importance of diligent maintenance and careful supervision during fixed retention, in particular, cannot be disregarded.

Comparison of efficacy of thermoplastic retainer with round and rectangular bonded lingual wire retainer in the mandible two years after orthodontic treatment: a randomised controlled trial

OBJECTIVE

To analyse three protocols in maintaining the stability of orthodontic therapy results and their effect on gingival health.

MATERIALS AND METHODS

Sixty-six subjects (pre-therapeutic age 11-18 years; 68% female) randomly allocated into three retention groups of equal size were analysed. The first group had a 0.673 × 0.268 mm (0.027 × 0.011 inches) rectangular braided steel retention wire bonded to the lingual surfaces of all mandibular teeth from canine to canine, and the second group had a 0.406 mm (0.016 inches) round twisted steel wire. The third group was the control, without wires, and only with vacuum-formed retainers. All three groups had vacuum-formed removable retainers in the maxilla. The frequency of wire detachment/breakage/loss of retainer, the occurrence of crowding of mandibular incisors, and changes in intercanine width and gingival health were monitored.

RESULTS

Incidence and severity of relapse differed between groups (p = 0.001 and 0.049) being most common in the removable retainer group (incidence 68.2%; severity 0.7 ± 1.0 mm), followed by the round wire group (36.4%; 0.5 ± 1.2 mm) and rectangular wire group (13.6%; 0.1 ± 0.1 mm). The intercanine width decreased more without a bonded retainer (incidence 68.2%; severity 0.5 ± 0.7 mm) and with the round wire more (45.5%; 0.5 ± 0.7 mm) than with the rectangular (27.3%; 0.1 ± 0.3 mm). The difference was significant for incidence (p = 0.025), but not severity. Detaching of the wires/breakage/loss of retainer was similar. There were no significant differences in the accumulation of biofilm, calculus and gingivitis between appliances.

CONCLUSION

A rectangular wire is the most effective in retention, and the impact of retention appliances on gingival health is similar.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT05121220. Registered 02 October 2021 - Retrospectively registered.

CLINICAL RELEVANCE

Studying guidelines for reducing relapse, proper use of materials and appliances, the behavior of retention wires according to their profile in the retention phase, and possibilities of maintaining oral health will contribute to improving the stability of orthodontic therapy results.

Direct 3D-Printed Orthodontic Retainers. A Systematic Review

Three-dimensional (3D) printing technology has shed light on many fields in medicine and dentistry, including orthodontics. Direct 3D-printed prosthetics, implants or surgical devices are well-documented. The fabrication of orthodontic retainers using CAD technology and additive manufacturing is an emerging trend but the available data are scarce. The research approach of the present review included keywords in Medline, Scopus, Cochrane Library and Google Scholar up to December 2022. The searching process concluded with five studies eligible for our project. Three of them investigated directly 3D-printed clear retainers in vitro. The other two studies investigated directly 3D-printed fixed retainers. Among them, one study was in vitro and the second was a prospective clinical trial. Directly 3D-printed retainers can be evolved over time as a good alternative to all the conventional materials for retention. Devices that are 3D-printed are more time and cost efficient, offer more comfortable procedures for both practitioners and patients and the materials used in additive manufacturing can solve aesthetic problems, periodontal issues or problems with the interference of these materials with magnetic resonance imaging (MRI). More well-designed prospective clinical trials are necessary for more evaluable results.

Orthodontic Retainers-A Critical Review

The achievement of aesthetic, functional occlusion should not mark the end of the orthodontic intervention. To prevent relapse, retention needs advance planning, and may vary in duration. This review aims to present and comment on the available means of retention. The ever-popular, passive Hawley-like removable appliances are credible in maintaining the desired occlusion. Modifications are the removable appliance Wrap Around, having the labial archwire extending to the premolars; the translucent retainer, Astics, a unique aesthetic Hawley-type device; and the reinforced removable retainer, which features a metallic grid reinforcing the acrylic base. Vacuum-formed retainers are easy to fabricate and are readily prescribed. By contrast, fixed retainers are made of orthodontic wire and composite resin bonded on the lingual or palatal surfaces of the anterior teeth. Patient-related variables need evaluation to select the appropriate retainer, while patients ought to realize the importance of retention and comply with offered guidance. Overall, the orthodontist is responsible for keeping the patient informed on the properties and the duration of retention, even before starting active orthodontic treatment.

Orthodontic Retainers-A Critical Review

The achievement of aesthetic, functional occlusion should not mark the end of the orthodontic intervention. To prevent relapse, retention needs advance planning, and may vary in duration. This review aims to present and comment on the available means of retention. The ever-popular, passive Hawley-like removable appliances are credible in maintaining the desired occlusion. Modifications are the removable appliance Wrap Around, having the labial archwire extending to the premolars; the translucent retainer, Astics, a unique aesthetic Hawley-type device; and the reinforced removable retainer, which features a metallic grid reinforcing the acrylic base. Vacuum-formed retainers are easy to fabricate and are readily prescribed. By contrast, fixed retainers are made of orthodontic wire and composite resin bonded on the lingual or palatal surfaces of the anterior teeth. Patient-related variables need evaluation to select the appropriate retainer, while patients ought to realize the importance of retention and comply with offered guidance. Overall, the orthodontist is responsible for keeping the patient informed on the properties and the duration of retention, even before starting active orthodontic treatment.

Comparison of periodontal status and failure rates with different retainer bonding methods and adhesives: a randomized clinical trial

OBJECTIVES

This single-center, randomized clinical trial evaluated and compared retainer bonding among different methods and adhesives in terms of periodontal status and failure rates.

MATERIALS AND METHODS

A total of 100 patients from the orthodontic department of Pamukkale University were randomly assigned to the following 4 groups: group 1, direct bonding (DB) with two-step adhesive; group 2, DB with one-step adhesive; group 3, indirect bonding (IDB) with two-step adhesive; and group 4, IDB with one-step adhesive. Eligibility criteria included good finishing results and oral hygiene, no periodontal or systemic problems, and no missing anterior teeth or restorations. Randomization was carried out using computer-generated random numbers with allocation concealment by opaque, sealed envelopes. The main outcomes were plaque index (PI), gingival index (GI), and calculus index (CI) recorded at bonding, 6 months (T1), and 12 months (T2) after bonding. A secondary outcome was failure rate. The periodontal outcome assessor was blinded. Data were analyzed using the Mann-Whitney U-test, Kruskal-Wallis test, and chi-square test.

RESULTS

PI and GI increased with time in all study groups, but there were no significant differences among groups at any time point. A small amount of calculus was observed in all study groups, with the increase in CI for group 3 significantly greater at the T2-T1 time interval (P < .05). There were no significant differences between groups for 12-month failure rates.

CONCLUSIONS

The one-step retainer adhesive was similar in terms of periodontal status and failure rate. Therefore, a one-step adhesive can be used during bonding, regardless of technique.

Survival analysis of three types of maxillary and mandibular bonded orthodontic retainers: a retrospective cohort

BACKGROUND

Retention is an important aspect of orthodontic treatment. This study aimed to analyze the survival of three types of maxillary and mandibular bonded orthodontic retainers.

METHODS

This retrospective cohort study evaluated the records of 118 orthodontic patients (90 females, 28 males, mean age of 22.34 ± 6.44 years) retrieved from a private orthodontic office. Data regarding the retainer failure, dental caries, unwanted tooth movements, maximum pocket depth (PD), and bleeding on probing (BOP) recorded at the follow-up sessions were extracted from patient records. Three types of retainer wires namely Bond-A-Braid, Orthoflex, and Retainium were compared regarding the abovementioned parameters. Data were analyzed by ANOVA, Chi-square, Monte-Carlo Chi-square, and Kruskal Wallis tests, the log rank test, and the Cox regression model.

RESULTS

The frequency of retainer failure was not significantly different between males and females, different age groups, or different treatment durations (P > 0.05). Wire fracture was the most common failure type in both the maxilla and mandible. Also, the frequency of failure was not significantly different between the maxillary and mandibular retainers (P > 0.05). The frequency of failure, and survival of the three types of retainer wires were not significantly different during a 5-year period (P > 0.05).

CONCLUSIONS

The three types of orthodontic retainers had comparable survival rates. Their failure rate was not correlated with the age or gender of patients or the treatment duration.

Metal versus Fiberglass Post-Orthodontic Retainers Short-Term Effects on Plaque Index and Microbial Colonization: An Observational Study

In orthodontics, post-treatment retention phase is crucial for maintaining the obtained clinical results. In cases of crowding, a bonded fixed retainer is often chosen to maintain teeth alignment in the anterior sector of the lower dental arch. A fixed retainer can remain in the mouth for years. Therefore, it is important that it is applied with harmless materials for the level of plaque control. The present study aimed to investigate the salivary concentrations of Streptococcus mutans (S. mutans) and Lactobacilli, and the Sillness and Loe plaque index, in patients wearing metal wire versus fiberglass orthodontic retainers. Forty post-orthodontic patients were included in the sample: in 20 subjects a metal wire retainer was applied (MR), while in the others a fiberglass retainer was applied (FR). The variables were recorded at baseline (T0), after 1 month (T1), and after 2 months (T2) of follow-up. The percentage of patients with a level of S. mutans and Lactobacilli colonization > 105 increased over time in the FR group (T0 = 0%, T1 = 5%, T2 = 35%), compared with the MR group. PI increased in the FR group (T0 = 0, T1 = 14, T2 = 27), and remained almost the same in the MR group (T0 = 3, T1 = 0, T2 = 2). From the present results it appears that the metal wire retainer is better than the fiberglass retainer for the level of plaque control performed by the patients.

Effect of Direct versus Indirect Bonding Technique on the Failure Rate of Mandibular Fixed Retainer-A Systematic Review and Meta-Analysis

INTRODUCTION

Fixed retainer failure is a common cause of relapse and may require additional orthodontic treatment. The two main methods for bonding the mandibular fixed retainer include direct and indirect techniques. This topic has not been explored previously in a systematic review. Therefore, the objective of this systematic review was to evaluate the effect of direct versus indirect bonding technique on the failure rate of mandibular fixed retainer.

METHODS

Online databases (PubMed, Dental and Oral Science, CINAHL, and Cochrane Central Register of Controlled Trials, Scopus) were systematically searched electronically for articles up until April 2021. Google Scholar and clinicaltrials.gov databases were utilized for hand searching. Randomized, non-randomized clinical trials and cohort studies on human subjects were considered regardless of language or year of publication. Orthodontic patients in their retention phase (mandibular 3×3 fixed retainer), in which the retainer was bonded using direct bonding technique as control and indirect as intervention were included. The outcome assessed was retainer failure rate. Two authors independently examined and extracted the data from the studies that satisfied the inclusion criteria. Risk of bias in clinical trials was assessed using the Cochrane Collaboration's tool, whereas risk of bias in cohort studies was assessed using the Newcastle-Ottawa Scale. The meta-analysis was conducted using the RevMan software V.5.3.5.22. The outcome was estimated using weighted average difference and 95% confidence intervals (CIs). The studies' heterogeneity was assessed using Cochrane's heterogeneity test (I2 Test).

RESULTS

Four articles fulfilling the inclusion criteria were included in qualitative and quantitative synthesis. Retainer failure rates were analysed in a total number of 266 patients bonded with mandibular 3×3 retainers after orthodontic therapy. Direct bonding technique of fixed retainer on 131 patients was compared with indirect technique on 135 patients. There was no statistically significant difference in the rate of retainer failure between the two methods (95% CI, 0.67, 1.40).

CONCLUSIONS

Within the limitations of insufficient evidence this systematic review and meta-analysis concluded that there is no difference in the failure rate of mandibular fixed retainers between direct and indirect bonding techniques. Due to the scarcity of available data, further studies are needed to establish definitively one's clinical benefit over the other.

Effects of different lingual retainers on periodontal health and stability

OBJECTIVES

To evaluate the effects of different lingual retainers on periodontal health and stability of mandibular anterior teeth at the 1-year follow-up.

MATERIALS AND METHODS

One hundred thirty-two patients were randomly allocated to four groups using different lingual retainers: group 1, 0.016 × 0.022-in dead-soft wire; group 2, 0.0215-in 5-strand stainless steel wire; group 3, 0.014 × 0.014-in computer-aided design/computer-aided manufacturing nitinol retainer (Memotain); group 4, connected bonding pads. Plaque, gingival, and calculus indexes were used to evaluate periodontal health, and Little's irregularity index, intercanine width, and arch length measurements were performed to evaluate stability. All measurements were performed at each time point (debonding and 3, 6, 9, and 12 months).

RESULTS

The mean value of the gingival index obtained in group 3 was lower than the mean value for all other groups. The mean value of the calculus index was the lowest in group 3, and there was a significant difference between group 3 and groups 1 and 2. No differences were found among the groups in terms of plaque index, intercanine width, and arch length. The least irregularity was obtained in groups 2 and 3. There were no significant differences between these groups and groups 1 and 4.

CONCLUSIONS

Gingival inflammation and calculus accumulation were the lowest in group 3 (Memotain). The irregularity for Memotain and stainless steel retainers was less than or the other groups. However, no clinically significant worsening of periodontal health or relapse were seen in any groups after 1 year.

Clinical factors affecting the longevity of fixed retainers and the influence of fixed retainers on periodontal health in periodontitis patients: a retrospective study

PURPOSE

The aim of this study was to evaluate clinical factors affecting the longevity of fixed retainers and the influence of fixed retainers on periodontal health in periodontitis patients.

METHODS

In total, 52 patients with at least 2 years of follow-up after periodontal and orthodontic treatment were included in this study. After scaling and root planing, orthodontic treatment with fixed appliances or clear aligners was performed. Fixed retainers with twist-flex stainless steel wires were bonded to the palatal or lingual sides of anterior teeth. Changes in clinical parameters, including the plaque index, gingival index, calculus index (CI), probing pocket depth, and radiographic bone levels, were evaluated before bonding of fixed retainers and at a 12-month follow-up. Cumulative survival rates (CSRs) for retainer failure were evaluated according to sex, site, CI, stage of periodontitis, and the severity of the irregularity with the log-rank test and hazard ratios (HRs).

RESULTS

Twelve months after bonding of fixed retainers, improvements were observed in all clinical parameters except CI and radiographic bone gain. The overall CSR of the retainers with a CI <1 at the 12-month follow-up after bonding of fixed retainers was significantly higher than that of the retainers with a CI ≥1 at the 12-month follow-up (log-rank test; P<0.001). Patients with stage III (grade B or C) periodontitis had a higher multivariate HR for retainer failure (5.4; 95% confidence interval, 1.22-23.91; P=0.026) than patients with stage I (grade A or B) periodontitis.

CONCLUSIONS

Although fixed retainers were bonded in periodontitis patients, periodontal health was well maintained if supportive periodontal treatment with repeated oral hygiene education was provided. Nonetheless, fixed retainer failure occurred more frequently in patients who had stage III (grade B or C) periodontitis or a CI ≥1 at 12-month follow-up after bonding of fixed retainers.

The effects of fixed orthodontic retainers on periodontal health: A systematic review

INTRODUCTION

The objective of this systematic review was to assess the available evidence in the literature for the effects of fixed orthodontic retainers on periodontal health.

METHODS

The following databases were searched up to August 31, 2019: Medline, EMBASE, the Cochrane Oral Health Group's Trials Register, CENTRAL, ClinicalTrials.gov, the National Research Register, and Pro-Quest Dissertation Abstracts and Thesis database. Randomized controlled trials (RCTs), controlled clinical trials, cohort studies of prospective and retrospective design, and cross-sectional studies reporting on periodontal measurements of patients who received fixed retention after orthodontic treatment were eligible for inclusion. The quality of the included RCTs was assessed per the revised Cochrane risk of bias tool for randomized trials (RoB 2.0), whereas the risk of bias of the included cohort studies was assessed using the Risk Of Bias In Nonrandomized Studies of Interventions tool. A modified version of the Newcastle-Ottawa scale was used for cross-sectional studies.

RESULTS

Eleven RCTs, 4 prospective cohort studies, 1 retrospective cohort study, and 13 cross-sectional studies fulfilled the inclusion criteria. The quality of evidence was low for most of the included studies. In contrast to the general consensus, 2 RCTs, 1 prospective cohort study, and 2 cross-sectional studies reported poorer periodontal conditions in the presence of a fixed retainer. The results of the included studies comparing different types of fixed retainers were heterogeneous.

CONCLUSIONS

According to the currently available literature, orthodontic fixed retainers seem to be a retention strategy rather compatible with periodontal health, or at least not related to severe detrimental effects on the periodontium.