Survival time comparison between Hawley and clear overlay retainers: a randomized trial

Assessment of wear characteristics, longevity and stiffness of Essix-type retainers

OBJECTIVE

To compare four commercially available Essix-type retainers in terms of longevity, wear characteristics, stiffness and their range of rigidity.

MATERIALS AND METHODS

An in vitro study was conducted at Queen Mary University of London. Four groups of thermoplastic materials were included: Duran (PETG), Essix C + (Polypropylene), Vivera and Zendura (Polyurethane). A working typodont was fabricated to evaluate surface wear characteristics using a wear machine with a customized jig. Retainers were measured for tensile test, and water absorption was measured at five different time points up to 6 months after initial immersion in two different physical states and two different solutions. Hydrolytic degradation was also evaluated using FTIR spectroscopy.

RESULTS

Essix C + was the most flexible retainer with Vivera the stiffest material. Zendura and Essix C + had the most surface wear (413 μm ± 80 and 652 μm ± 12, respectively) with absorption rates of up to 15 wt% in artificial saliva occurring with Zendura. Only Essix C + displayed signs of degradation following water absorption.

CONCLUSIONS

All materials had characteristic levels of flexibility and were susceptible to water absorption. Duran 1.5 mm performed similarly to Vivera in relation to stiffness and wear properties. While Zendura and Vivera have similar chemical structures, they exhibited differences concerning wear resistance and water absorption. Further clinical research evaluating the clinical relevance of these laboratory findings is required.

CLINICAL RELEVANCE

Characteristic patterns of wear and rigidity of four commercially available Essix-type retainers were observed. This information should help in the tailoring of retainer material on a case-by-case basis considering treatment-related factors and patient characteristics including parafunctional habits.

Blanket or tailored prescription of retainers in orthodontics: a questionnaire-based study

OBJECTIVE

To explore retainer protocols and how they are influenced by orthodontic presentation and the nature of occlusal correction.

MATERIALS AND METHODS

A prepiloted 45-item online questionnaire targeting orthodontists was developed. The questionnaire covered clinical preferences in terms of retainer type, fabrication, and follow-up during retention; the clinical indications for adjunctive surgical procedures; and the use of active designs to mitigate relapse in specific malocclusions.

RESULTS

A total of 206 responses were obtained. The majority of the respondents prescribed maxillary removable and mandibular fixed retainers, with almost half (49.1%) reviewing patients for more than 1 year primarily in person (95.1%). The majority prescribed vacuum-formed (69.6%) 1-mm-thick (44.3%) retainers. Only 37.3% were aware of the type of material used, with polyethylene terephthalate glycol copolymer, followed by polypropylene, being the most common. Hawley retainers were preferred following nonsurgical maxillary expansion and with suboptimal interdigitation. A preference for clear retainers and/or fixed retainers was found in open-bite cases and deep-bite cases. Supracrestal fiberotomy was prescribed commonly (61.1%) for rotations greater than 90°. No retainer was rarely prescribed except after the correction of an anterior crossbite.

CONCLUSIONS

Blanket prescription of orthodontic retention is common, with limited awareness of clear plastic retainer materials. Future trials evaluating the effectiveness of approaches for retainer prescription based on the presenting malocclusion would be timely.

Retention procedures for stabilising tooth position after treatment with orthodontic braces

BACKGROUND

Without a phase of retention after successful orthodontic treatment, teeth tend to 'relapse', that is, to return to their initial position. Retention is achieved by fitting fixed or removable retainers to provide stability to the teeth while avoiding damage to teeth and gums. Removable retainers can be worn full- or part-time. Retainers vary in shape, material, and the way they are made. Adjunctive procedures are sometimes used to try to improve retention, for example, reshaping teeth where they contact ('interproximal reduction'), or cutting fibres around teeth ('percision'). This review is an update of one originally published in 2004 and last updated in 2016.

OBJECTIVES

To evaluate the effects of different retainers and retention strategies used to stabilise tooth position after orthodontic braces.

SEARCH METHODS

An information specialist searched Cochrane Oral Health Trials Register, CENTRAL, MEDLINE, Embase and OpenGrey up to 27 April 2022 and used additional search methods to identify published, unpublished and ongoing studies.  SELECTION CRITERIA: Randomised controlled trials (RCTs) involving children and adults who had retainers fitted or adjunctive procedures undertaken to prevent relapse following orthodontic treatment with braces. We excluded studies with aligners.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened eligible studies, assessed risk of bias and extracted data. Outcomes were stability or relapse of tooth position, retainer failure (i.e. broken, detached, worn out, ill-fitting or lost), adverse effects on teeth and gums (i.e. plaque, gingival and bleeding indices), and participant satisfaction. We calculated mean differences (MD) for continuous data, risk ratios (RR) or risk differences (RD) for dichotomous data, and hazard ratios (HR) for survival data, all with 95% confidence intervals (CI). We conducted meta-analyses when similar studies reported outcomes at the same time point; otherwise results were reported as mean ranges. We prioritised reporting of Little's Irregularity Index (crookedness of anterior teeth) to measure relapse, judging the minimum important difference to be 1 mm.

MAIN RESULTS

We included 47 studies, with 4377 participants. The studies evaluated: removable versus fixed retainers (8 studies); different types of fixed retainers (22 studies) or bonding materials (3 studies); and different types of removable retainers (16 studies). Four studies evaluated more than one comparison. We judged 28 studies to have high risk of bias, 11 to have low risk, and eight studies as unclear.  We focused on 12-month follow-up.  The evidence is low or very low certainty. Most comparisons and outcomes were evaluated in only one study at high risk of bias, and most studies measured outcomes after less than a year. Removable versus fixed retainers Removable (part-time) versus fixed   One study reported that participants wearing clear plastic retainers part-time in the lower arch had more relapse than participants with multistrand fixed retainers, but the amount was not clinically significant (Little's Irregularity Index (LII) MD 0.92 mm, 95% CI 0.23 to 1.61; 56 participants). Removable retainers were more likely to cause discomfort (RR 12.22; 95% CI 1.69 to 88.52; 57 participants), but were associated with less retainer failure (RR 0.44, 95% CI 0.20 to 0.98; 57 participants) and better periodontal health (Gingival Index (GI) MD -0.34, 95% CI -0.66 to -0.02; 59 participants). Removable (full-time) versus fixed   One study reported that removable clear plastic retainers worn full-time in the lower arch did not provide any clinically significant benefit for tooth stability over fixed retainers (LII MD 0.60 mm, 95% CI 0.17 to 1.03; 84 participants). Participants with clear plastic retainers had better periodontal health (gingival bleeding RR 0.53, 95% CI 0.31 to 0.88; 84 participants), but higher risk of retainer failure (RR 3.42, 95% CI 1.38 to 8.47; 77 participants). The study found no difference between retainers for caries.  Different types of fixed retainers Computer-aided design/computer-aided manufacturing (CAD/CAM) nitinol versus conventional/analogue multistrand One study reported that CAD/CAM nitinol fixed retainers were better for tooth stability, but the difference was not clinically significant (LII MD -0.46 mm, 95% CI -0.72 to -0.21; 66 participants). There was no evidence of a difference between retainers for periodontal health (GI MD 0.00, 95% CI -0.16 to 0.16; 2 studies, 107 participants), or retainer survival (RR 1.29, 95% CI 0.67 to 2.49; 1 study, 41 participants). Fibre-reinforced composite versus conventional multistrand/spiral wire  One study reported that fibre-reinforced composite fixed retainers provided better stability than multistrand retainers, but this was not of a clinically significant amount (LII MD -0.70 mm, 95% CI -1.17 to -0.23; 52 participants). The fibre-reinforced retainers had better patient satisfaction with aesthetics (MD 1.49 cm on a visual analogue scale, 95% CI 0.76 to 2.22; 1 study, 32 participants), and similar retainer survival rates (RR 1.01, 95% CI 0.84 to 1.21; 7 studies; 1337 participants) at 12 months. However, failures occurred earlier (MD -1.48 months, 95% CI -1.88 to -1.08; 2 studies, 103 participants; 24-month follow-up) and more gingival inflammation at six months, though bleeding on probing (BoP) was similar (GI MD 0.59, 95% CI 0.13 to 1.05; BoP MD 0.33, 95% CI -0.13 to 0.79; 1 study, 40 participants). Different types of removable retainers Clear plastic versus Hawley When worn in the lower arch for six months full-time and six months part-time, clear plastic provided similar stability to Hawley retainers (LII MD 0.01 mm, 95% CI -0.65 to 0.67; 1 study, 30 participants). Hawley retainers had lower risk of failure (RR 0.60, 95% CI 0.43 to 0.83; 1 study, 111 participants), but were less comfortable at six months (VAS MD -1.86 cm, 95% CI -2.19 to -1.53; 1 study, 86 participants). Part-time versus full-time wear of Hawley There was no evidence of a difference in stability between part-time and full-time use of Hawley retainers (MD 0.20 mm, 95% CI -0.28 to 0.68; 1 study, 52 participants).

AUTHORS' CONCLUSIONS

The evidence is low to very low certainty, so we cannot draw firm conclusions about any one approach to retention over another. More high-quality studies are needed that measure tooth stability over at least two years, and measure how long retainers last, patient satisfaction and negative side effects from wearing retainers, such as tooth decay and gum disease.

"Comparing the effectiveness, acceptability and oral hygiene status between vacuum formed retainer and Begg's retainer": a pilot study

BACKGROUND

Recently, Vacuum formed retainers (VFRs) are preferred as an Orthodontic retention appliance over conventional Begg's retainers. Very few studies have been conducted between VFRs and Begg's retainers. Hence, this study aims at assessing the effectiveness, oral hygiene and acceptability between VFRs and Begg's retainers with a follow up period of 1 year.

METHODS

Eighty patients who completed fixed Orthodontic treatment were included. Retainers were delivered on the same day of debonding. Retainer 1/ R1 stands for VFRs and Retainer 2/ R2 stands for Begg's retainers. The retainers were randomly allocated to both the arches. 40 VFRs and Begg's retainers in maxillary and mandibular arch were given respectively. Effectiveness, oral hygiene condition were performed at T₀ (After debonding), T₁ (3 months after using retainers), T₂ (6 months after using retainers), T₃ (9 months after using retainers), T₄ (12 months after using retainers) follow up stages, except the feedback form and the breakage of retainers that were filled at T₄ stage.

RESULTS

Both R₁ and R₂ retainers showed improvement in teeth alignment in both the arches at follow up stages. Interproximal contacts in maxillary and mandibular arch with VFRs and Begg's retainers improved to 77.5% and 82.5% respectively. Considering the marginal ridge, Begg's retainers and VFRs showed 95%, 55% increased proportion at T₄ respectively (p < 0.05). Patients wearing Beggs's retainers had significantly better (p < 0.05) oral hygiene status. Significant differences were observed with Begg's retainers in teeth biting, whereas no significant difference was found with fitting of appliance (p = 0.180) and gingival irritation (p = 1.000). VFRs were well accepted aesthetically that was significant. Retainers were prone to breakage but was not significant (p = 0.162).

CONCLUSION

Begg's wrap around retainers maintain good oral hygiene, improve the teeth alignment, interproximal contact and marginal ridges post Orthodontic treatment with better fitting of the appliance. VFRs are also preferred as they are good in maintaining proper teeth alignment with progressive improvement in the interproximal contacts and are aesthetically pleasing.

Wear and fatigue resistance: An in-vitro comparison of three polyethylene terephthalate glycol and thermoplastic polyurethane materials for vacuum-formed retainers

OBJECTIVE

To test the wear and fatigue resistance of three materials (Essix ACE®, Taglus®, and Zendura A®) for the fabrication of vacuum-formed retainers in an artificial oral environment.

MATERIAL AND METHODS

Wear resistance was tested by subjecting 21 retainers of each Essix ACE®, Taglus®, and Zendura A® to 12,000 wear cycles at 75N to simulate one year of retainer wear with moderate nighttime bruxing. Post-wear retainer thickness was compared to baseline measurements to calculate wear depth. Fatigue resistance was tested by flexing 15 retainers of each material at an angle of 25 degrees for 1,825 cycles to simulate one year of removing and reinserting a retainer five times per day. Retainers were visually inspected for fractures. Pairwise t-tests with correction using Tukey's method were used to determine significant differences between materials.

RESULTS

The mean wear depths were 0.155±0.021mm, 0.168±0.031mm, and 0.096±0.033mm for Essix ACE®, Taglus®, and Zendura A®, respectively. The wear depth of Zendura A® was significantly lower than that of both Essix ACE® (P<0.001) and Taglus® (P<0.001). There was no significant difference in wear depth between Essix ACE® and Taglus® (P=0.312). Under the parameters set for the fatigue resistance test, fractures did not occur on any of the tested materials.

CONCLUSIONS

Under the assumption of moderate nighttime bruxing for one year, Zendura A® is the most wear-resistant among the materials tested. With the assumption of retainer removal and reinsertion five times per day for one year, all three materials tested have the same ability to resist fatigue.

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.

A two-year comparative assessment of retention of arch width increases between modified vacuum-formed and Hawley retainers: a multi-center randomized clinical trial

Objectives

To compare the clinical effectiveness of Hawley retainers (HRs) and modified vacuum-formed retainers (mVFRs) with palatal coverage in maintaining transverse expansion throughout a 24-month retention period and to assess the subjects’ perception toward the retainers.

Materials and methods

The trial accomplished blinding only by the outcome assessor and data analyst. Data were collected from post-orthodontic treatment patients who met the inclusion criteria. Thirty-five subjects were randomly allocated using a centralized randomization technique into either mVFR (n = 18) or HR group (n = 17). Dental casts of subjects were evaluated at debond (T0), 3-month (T1), 6-month (T2), 12-month (T3), and 24-month retention (T4). The intercanine width (ICW), interpremolar width (IPMW), interfirst molar mesiobuccal cusp width (IFMW1), and interfirst molar distobuccal cusp width (IFMW2) were compared between groups over time using Mixed ANOVA. A pilot-tested and validated questionnaire consisting of six items were given at T4. Subjects were instructed to rate their retainer in terms of fitting, speech, appearance, oral hygiene, durability, and comfort on a 100-mm Visual Analogue Scale (VAS).

Results

No statistically significant differences in arch width were found between the two groups at ICW (P = .83), IPMW (P = 0.63), IFMW1 (P = .22), and IFMW2 (P = .46) during the 24-month retention period. Also, no statistically significant differences were found between perception of both retainers in terms of fitting, speech, oral hygiene, durability, and comfort (P > .05) after 24-month wear. The appearance of mVFRs was rated significantly higher compared to HRs (P < .05).

Conclusions

HR and mVFR have similar clinical effectiveness for retention of transverse expansion cases in a 24-month retention period. Both retainers were perceived to be equal in terms of fitting, speech, oral hygiene, durability, and comfort. Subjects in the mVFRs group found their retainers to be significantly more esthetic than those in HRs group.

Capabilities of Digital Software for Creating a 3D Printed Retainer

INTRODUCTION: The retention phase of orthodontic treatment is an important phase to prevent teeth returning to their initial position. An innovative solution for creating a retainer is through 3D printing by digital design. AIM: The purpose of this article is to demonstrate the capabilities of digital software in the creation of stabilization splint, type retainer, and after orthodontic treatment. MATERIAL AND METHODS: An intraoral scan of an orthodontically treated patient (18 years) was performed. A Trios Color scanner (3Shape) was used. 3Shape Dental system design – splint studio was used for file processing and design creation. The method of 3D printing was applied to make the retainer. With this method, the objects are created layer by layer from melted material with different nature. It was made by Dental LT Clear Resin (a biocompatible material) with Formlabs Form 2 printer. RESULTS: Depending on the selected thickness of the retainer and the position of the lower jaw, the software generates different distances between the dentitions. The digital design allows a change of 0.1 mm, which is impossible with a classic laboratory protocol. The resulting printed retainer fully meets our expectations – tooth adaptation, patient comfort, and aesthetics. CONCLUSION: Digital software and design provide many opportunities for modern orthodontics.

Treatment stability with bonded versus vacuum-formed retainers: a systematic review of randomized clinical trials

BACKGROUND

In orthodontics, the retention phase can be considered challenging and unpredictable. Therefore, evidence obtained from different retention protocols is important to facilitate clinical decision-making.

OBJECTIVES

This systematic review aimed to compare the clinical effectiveness of bonded versus vacuum-formed retainers (VFRs) regarding their capacity to maintain treatment stability, periodontal effects, and failure rates.

SEARCH METHODS AND ELIGIBILITY CRITERIA

Ten databases comprising published and unpublished literature were systematically searched up to August 2021. Randomized clinical trials (RCTs) comparing both retainers were included.

DATA COLLECTION AND ANALYSIS

The risk of bias (RoB) evaluation was performed with the Cochrane Collaboration RoB Tool 2.0. All steps of the screening phase and RoB assessment were performed independently by two reviewers. The Grade of Recommendations, Assessment, Development, and Evaluation (GRADE) was used to evaluate the certainty of the evidence.

RESULTS

Initial database search yielded 923 studies. After duplicates removal and full-text assessment, five RCTs remained. Overall, the studies presented Low RoB, except one study judged with 'Some concerns'. Based on the included studies, on a short-term (3-6 months) and long-term (4 years) basis, bonded retainers (BRs) were more effective to maintain treatment stability than VFRs in the lower arch. However, from 12 to 24 months both retainers presented the same efficacy. In the upper arch, the retainers were equally effective. BRs were associated with greater plaque and calculus accumulation than VFRs after 12 months. The retainers' failure rates were similar in the upper arch on the first year of retention; however, after 2 years VFRs showed significantly greater failure rates. Contrarily, BRs presented greater failure rates in the lower arch than VFRs.

LIMITATIONS

The findings of the included studies may be influenced by different factors related to the unpredictability of relapse.

CONCLUSIONS

Most of the evidence generated in this systematic review derived from a moderate level of certainty. In the lower arch, BRs are more effective than VFRs to maintain treatment stability in the initial 6 months of retention and in the long term. In the upper arch, both retention protocols are equally effective.

REGISTRATION

Regist0ration number: PROSPERO CRD42020199392.

FUNDING

Coordination for the Improvement of Higher Educational Personnel (CAPES, Process code-001).

Is YouTube an adequate patient resource about orthodontic retention? A cross-sectional analysis of content and quality

INTRODUCTION

The study aimed to evaluate the content and quality of information offered by YouTube for patients seeking information related to orthodontic retainers.

METHODS

YouTube was searched using the keyword "orthodontic retainers" from Google Trends. From the first 120 results, 97 videos were selected to be analyzed. Videos were rated for quality by video information and quality index (VIQI) and the global quality scale (GQS). Videos were classified as low- and high-content groups using a 10-point score considering several retainer-related topics. Mann-Whitney U tests, chi-square tests, and Pearson correlation coefficients were used for statistical evaluations.

RESULTS

Most YouTube videos were uploaded by dentists/specialists (62.9%). We classified 12 videos as high content and 85 as low content. Instructions on the use of the orthodontic retainer was the most commonly covered topic (42.3%), followed by the effect on oral hygiene (38.1%), definition (37.1%), procedure of preparing orthodontic retainers (33.0%), and procedure of positioning (30.9%). A lower percentage of videos (6.2%) mentioned soft tissue irritation. The high-content video group had a significantly higher median value of GQS score and VIQI (P <0.001). The correlation between GQS and VIQI was strong (r = 0.698; P <0.01).

CONCLUSIONS

The content of YouTube videos for orthodontic retainers could not be considered as an adequate source of information for patients on orthodontic retainers. Most videos included instructions on the use of orthodontic retainers, but fewer videos mentioned the effect on speech performance and soft tissue irritations.

Assessment of the effect of vacuum-formed retainers and Hawley retainers on periodontal health: A systematic review and meta-analysis

Background

Recently, increasing attention has been paid to the periodontal health of orthodontic patients in the maintenance stage in clinical practice. The focus of this meta-analysis was to compare the effects of vacuum-formed retainers (VFR) and Hawley retainers (HR) on periodontal health, in order to provide a reference for clinical selection.

Methods

From the establishment of the database until November 2020, a large number of databases were searched to find relevant randomized control trials, including the Cochrane Library databases, Embase, PubMed, Medline via Ovi, Web of Science, Scopus, Grey Literature in Europe, Google Scholar and CNKI. Related literature was manually searched and included in the analysis. Two researchers screened the literature according to relevant criteria. The size of the effect was determined using RevMan5.3 software, and the mean difference and 95% confidence intervals (CI) were used to estimate the results using a random effects model.

Results

This meta-analysis included six randomized controlled trials involving 304 patients. The results of the meta-analysis showed that there was no statistical difference in sulcus probing depth status between the VFR group and the HR group, including at 1, 3, and 6 months. Compared with the VFR group, the HR group showed a lower gingival index at 1 month (mean difference = 0.12, 95%CI: 0.06 to 0.19) and 3 months (mean difference = 0.11, 95%CI: 0.06 to 0.17), while there was no statistically significant difference at 6 months (mean difference = 0.10, 95%CI: -0.07 to 0.27). The plaque index of the HR group also showed a good state at 1 month (mean difference = 0.06, 95%CI: 0.01 to 0.12), 3 months (mean difference = 0.12, 95%CI: 0.08 to 0.16), and 6 months (mean difference = 0.19, 95%CI: 0.09 to 0.29). Subgroup analysis of PLI showed that when all teeth were measured, PLI status was lower in the HR group at 6 months (mean difference = 0.32, 95%CI: 0.18 to 0.46). PLI status was also low for the other teeth group (mean difference = 0.15, 95%CI: 0.08 to 0.22).

Conclusion

Our meta-analysis showed that patients using the Hawley retainer had better periodontal health compared with those using vacuum-formed retainers. However, more research is needed to look at the periodontal health of patients using these two retainers.

Orthodontic retention protocols: an evidence-based overview

In view of the diversity of orthodontic presentations, a single optimal retention protocol does not exist, with approaches tailored based on pre-treatment characteristics, treatment-induced changes and general patient characteristics. However, orthodontic practitioners should be responsive to the best available evidence to formulate optimal retention protocols in terms of appliance type, design and regimen, in particular. Based on a comprehensive search strategy, we discuss fundamental aspects concerning orthodontic retention of particular interest both to orthodontists and general dentists. These include stability and periodontal outcomes, cost-effectiveness, patient experiences, survival and failure rates of retainers, and the duration of retention.

Removable orthodontic retainers: practical considerations

This article provides an overview of removable orthodontic retainers, discussing their history and the different types available, and compares the two most popular removable retainers. Practical information on consent and the clinical steps involved in the provision of removable retainers, as well as suggested wear and care instructions, are also presented.

The origin and evolution of the Hawley retainer for the effectiveness to maintain tooth position after fixed orthodontic treatment compare to vacuum-formed retainer: A systematic review of RCTs

OBJECTIVE

This systematic review aims to summarize the effectiveness and patient compliances of Hawley retainer (HR) compared to vacuum-formed retainers (VFR) and provide the best clinical evidence related to the use of these retainers for maintaining tooth position following fixed orthodontic appliance so that orthodontists can decide which are the most appropriate methods and retainers to use for each individual patient.

MATERIALS AND METHODS

We searched the Cochrane Library, EMBASE, PubMed, Web of Science, Orthodontic journals, and relevant articles for eligible studies. Only RCTs studies were included; no restrictions on publication status or language were applied until May 20, 2019. We collected the study related to the effectiveness of these two retainers. Furthermore, patient-reported outcomes, survival time, cost-effectiveness, occlusal contact, and adverse effect on gingival and speech articulation were also collected.

RESULTS

We finally included fifteen articles in the qualitative synthesis. No significant difference was observed in patients who had worn the retainers on a full-time or part-time, basis in both HR and VFR in terms of the change in arch widths and arch lengths. VFR appeared to be better at preventing relapses of incisor irregularity than HR. Patient satisfaction with VFR was higher than with HR, and there was no difference in survival rates for both types of retainers. In terms of cost-effectiveness, occlusal contacts, and gingival health, there were a few studies with limited evidence to compare these retainers. For speech articulation, VFR was less affected in comparison to HR.

CONCLUSIONS

We found that wearing VFR provides better relapse prevention of incisor irregularity than HR in both arches, indicating their usefulness in clinical practice. However, there is no evidence to show that the pattern of time duration wearing these retainers provides excellent stability. Overall, there are insufficient high-quality RCTs to provide additional evidence, and further high-quality RCTs research is needed.

Survival of maxillary and mandibular bonded retainers 10 to 15 years after orthodontic treatment: a retrospective observational study

BACKGROUND

The long-term evidence regarding failures of fixed retainers is limited and the aim of this cohort study was to assess the long-term risk of failure of one type of maxillary and two types of mandibular fixed lingual retainers.

TRIAL DESIGN

Retrospective cohort study.

METHODS

Eighty-eight patients in retention 10-15 years after orthodontic treatment were included. The type of failure; number of failures per tooth, per patient, and retainer; and adverse effects were assessed by (1) a questionnaire, (2) clinical examination, and (3) screening patients' clinical charts. Descriptive statistics were calculated and a Cox regression was used to assess possible predictors for mandibular retainer survival.

RESULTS AND CONCLUSIONS

In the mandible, 47 (53.4%) .016″ × .022″ braided stainless steel retainers (SS) were bonded to all six anterior teeth, and 41 (46.6%) .027″ β-titanium (TMA) retainers were bonded to the canines only. From the SS retainers 40.4% and of the TMA retainers 61% had no failures during the whole observation period. SS failures per retainer were 2.17 (3.15) vs. 0.66 (1.03) for TMA. The type of retainer was the only significant predictor for failure. In the maxilla, 82 (93.2%) .016″ × .022″ braided SS retainers were bonded to all four incisors and six retainers (6.8%) to all six anterior teeth. The latter group was not further analyzed due to the small sample size. From the retainers bonded to all four incisors, 74.4% had no failure during the whole observation period. SS average number of failures per retainer bonded to the four incisors was 1.14 (SD 2.93). Overall, detachments were the most frequent type of first failure followed by composite damage. From the original mandibular retainers 98.9% and of the original maxillary retainers 97.6% were still in situ 10-15 years after debonding. No adverse torque changes were observed.

LIMITATIONS

Potential effects of selection bias, information bias, and attrition bias as well as possible confounding factors cannot be fully excluded in this study.

Development of a clinical practice guideline for orthodontic retention

OBJECTIVES

To develop a clinical practice guideline (CPG) for orthodontic retention (OR).

MATERIALS AND METHODS

The CPG was developed according to the AGREE II instrument and EBRO (Dutch methodology for evidence-based guideline development). Reporting was done according the RIGHT statement. A Task Force developed clinical questions regarding OR. To answer these questions, a systematic literature search in PubMed and EMBASE was performed. Two independent researchers identified and selected studies, assessed risk of bias using Cochrane RoB tool and rated quality of evidence using GRADE. The Task Force formulated considerations and recommendations after discussing the evidence. The concept CPG was sent for commentary to all relevant stakeholders.

RESULT

One systematic review-with 15 studies-met the inclusion criteria. In case of low evidence and lack of outcome measures, expert-based considerations were developed. Over four meetings, the Task Force reached consensus on considerations and recommendations, after which the concept CPG was ready for the commentary phase. After processing the comments, the CPG was presented to the Dutch Association of Orthodontists, whereafter authorization followed.

LIMITATIONS

The paucity of evidence-based studies concerning OR and the reporting of measurable patient outcomes.

CONCLUSION

This CPG offers practitioner recommendations for best practice regarding OR, may reduce variation between practices and assists with patient aftercare. A carefully chosen retention procedure for individual patients, combined with clear information and communication between orthodontist, dentist and patient will contribute to long-term maintenance of orthodontic treatment results.

Performance of Hawley-type retainers: a systematic review of randomized clinical trials

Background

Although post-treatment changes are almost inevitable, and retention has long been recognized as one of the most critical and routine problems faced by orthodontists, there remains a lack of certainty regarding the parameters of any definitive retention protocol following orthodontic treatment.

Objective

To investigate the performance of the Hawley-type retainers.

Search methods

Search without restrictions in 15 databases and hand searching until December 2016.

Selection criteria

Randomized clinical trials comparing the performance of Hawley-type retainers to other removable appliances or comparing different Hawley-type retainers' wearing schedules.

Data collection and analysis

Following study retrieval and selection, data extraction and individual study risk of bias assessment using the Cochrane Risk of Bias Tool took place. The overall quality of the available evidence was assessed with the Grades of Recommendation, Assessment, Development, and Evaluation approach.

Results

Finally, 10 studies were identified involving 854 individuals, followed for up to 1 year after debonding. Eight studies compared subjects using Hawley and clear thermoplastic retainers; another compared Hawley to positioner and, finally, one trial involved individuals allocated to different Hawley appliance wearing schedules. Three studies were considered as being of low, four of unclear, and three of high risk of bias. In general, few differences were observed between the Hawley and other removable retainers regarding outcomes relevant to maxillary and mandibular dental arch measurements, dental arch relationships and occlusal contacts, speech evaluation, patient reported outcomes, adverse effects, and problems related to the appliances, as well as economic evaluation related outcomes. Moreover, no differences were observed between the compared Hawley wearing schedules. Overall, the quality of the available evidence was considered low.

Conclusions

Given the overall quality of the available evidence and the multitude of parameters, which may have affected the results of the included trials, good practice would suggest further research in the respective field in order to increase both the quantity and quality of information available.

Registration

PROSPERO (CRD42015029279).

Funding

No funding was received for the present systematic review.

A systematic review of orthodontic retention systems: The verdict

INTRODUCTION

Retention during both the active and passive phases of treatment has given rise to numerous publications concerning its efficacy, the range of systems available and its variability over time. There are currently many different retention protocols regularly used by orthodontists; however, their efficacy and duration are still subject to debate. There is as yet no consensus as to which retention protocol is the most effective or for how long the retention device needs to be worn. The aim of this research was to perform a systematic review of the scientific literature in order to evaluate the efficacy of the different retention systems and clinical protocols among those most widely used, so as to make recommendations beneficial to both patient and practitioner.

MATERIALS AND METHODS

A search of the literature was performed in the following databases: PubMed (MEDLINE), ScienceDirect and Cochrane Library. The search was limited to publications in English and French during the period 2006-2016.

RESULTS

Out of 1952 references initially identified, 17 articles corresponded to our inclusion criteria. The results show that: fixed retention is more effective than removable retainers for the maintenance of incisor alignment during the first six months of retention; there is no significant difference in efficacy between the different fixed retention systems; there is no significant difference in efficacy between the vacuum-formed systems and the Hawley retainer; part-time use of removable retainers (between 8-10h/day) is sufficient; the most widely used retention protocol combines a vacuum-formed splint or Hawley retainer in the upper arch with mandibular fixed retention.

CONCLUSION

Despite the large number of studies devoted to orthodontic retention only a few articles corresponded to the methodological criteria of bio statistical analysis. Also, on account of the variations in experimental protocols, the levels of proof relating to the efficacy of different systems are very weak. Research into this topic should first seek to normalize methods of analysis and then perform randomized controlled long-term trials to shed light on this problem.

Orthodontic thermoformed retainers: a two-arm laboratory study into post-fabrication outcomes

BACKGROUND

Retainers are commonly used to maintain post-orthodontic occlusion stability. We aimed to determine post-fabrication thickness and thinning rate of thermoformed retainers.

METHODS

Forty-eight retainers were fabricated from polyethylenterepthalat-glycol copolyester or polypropylene blanks, using vacuum- or pressure-thermoforming. Retainer thickness was measured at multiple locations.

RESULTS

Thinning rate had a broad range: the mid-labial incisor region of 1 mm polyethylenterepthalat-glycol copolyester pressure-thermoformed mandibular retainers had the greatest thinning rate (68.25 ± 8.26%) and smallest mean post-fabrication thickness (0.32 ± 0.08 mm). Polyethylenterepthalat-glycol copolyester retainers were 0.11 mm thinner than polypropylene (P=0.0222), and polypropylene retainers were 0.21 mm thicker, when pressure-thermoformed (P<0.0001). The interaction of manufacturing method and material used, and tooth type, explained over a third of the variability in the post-fabrication thickness of these retainers. Maxillary retainers made from 1 mm blanks were 0.04 mm thicker in the incisor region compared with the molar region (P=0.0492).

CONCLUSIONS

Thermoformed retainers do no thin uniformly against individual teeth and have variable intra- and inter-arch post-fabrication thicknesses. There is no clear benefit in using a specific type of thermoforming machine or material for increasing post-fabrication thickness or reducing thinning rate. Blank thickness and tooth morphology influence these outcomes.

Comparison of Stability of the Results of Orthodontic Treatment and Gingival Health between Hawley and Vacuum-formed Retainers

Aim: Retention is one of the stages of orthodontic treatment, which is an attempt to retain teeth in their corrected positions after active treatment with the use of fixed orthodontic appliances. The aim of the present study was to compare the stability of the results of orthodontic treatment and the gingival health between Hawley retainer (HR) and vacuum-formed retainer (VFR) with two different thicknesses. Materials and methods: In this randomized clinical trial, 66 patients undergoing comprehensive orthodontic treatment in a private office were evaluated after completion of treatment. The subjects were randomly assigned to three groups. At the end of orthodontic treatment, the subjects in all the groups received a fixed bonded retainer in the mandible; in the maxilla, group I received an HR, group II received a VFR with a thickness of 1.5 mm, and group III received a VFR with a thickness of 1 mm. The American Board of Orthodontics objective grading system (ABO-OGS) index was used at the end of treatment (before the delivery of the retainers) and 6 months after the use of retainers to evaluate the stability of the results of orthodontic treatment. Gingival index (GI) was used at the two above-mentioned intervals to evaluate gingival health. The ABO-OGS measurements were carried out on dental casts by a clinician who was blinded to the types of retainers the patients wore. Data were analyzed with Statistical Package for the Social Sciences (SPSS) version 20, using proper statistical analyses. Results: Six months after the delivery of retainers, ABO-OGS and GI scores with the 1.5 mm VFR were higher than those in the two other groups, with no significant differences between the three groups. There were no significant differences between the ABO-OGS scores before the delivery of retainers and 6 months after the use of retainers in any of the study groups. In the HR and 1.5 mm VFR groups, there were significant differences in GI scores between the period before the delivery of the retainers and 6 months after their delivery; however, in the 1 mm VFR group, no significant differences were observed in GI scores between the two time intervals. Conclusion: Hawley retainer and 1 mm thick and 1.5 mm thick VFRs were equally effective in preserving and stabilizing the results of orthodontic treatment during the 6-month interval after the completion of orthodontic treatment. In addition, there were no significant differences between the three retainers in relation to gingival health. Clinical significance: The VFR might be a good alternative for HR due to its better esthetic appearance and greater popularity with orthodontic patients. Keywords: American Board of Orthodontics model grading system, American Board of Orthodontics objective frading system, Gingival index, Hawley retainers, Vacuum-formed retainers.

Clear retainer

A clear retainer is a removable retainer that is popular in the present day. Compared with conventional fixed and removable orthodontic retainers, it is a more esthetic, comfortable, and inexpensive appliance. Although several studies have been published about clear retainers, it could be difficult to interpret the results because of the variety of study designs, sample sizes, and research methods. This article is intended to compile the content from previous studies and discuss advantages, disadvantages, fabrication, insertion, and adjustment. Moreover, the effectiveness in maintaining dental position, occlusion, retention protocols, thickness, and survival rate of clear retainers is discussed.

The Limitations of Short-Term Orthodontics and Why We Still Need Specialists – A Review of the Current Literature

Short-term orthodontics (STO) serves to align anterior teeth. It has become popular in cosmetic dentistry as an alternative to destructive veneers and lengthy conventional orthodontics. The aim of this article is to raise awareness of the clinical limitations of STO and highlight some of the difficulties encountered with orthodontic retention. It also gives an overview of accredited training available to dentists who wish to develop their orthodontic skills. Clinical relevance: Greater awareness of the clinical limitations of short-term orthodontics will aid GDPs in appropriately selecting their cases and obtaining informed consent from patients. In addition, the article serves as encouragement for those GDPs wishing to develop their orthodontic skills and pursue further accredited training.

Speech effects of Hawley and vacuum-formed retainers by acoustic analysis: A single-center randomized controlled trial

OBJECTIVE

To investigate the effects of alteration on speech articulation of adult patients between Hawley retainers and vacuum-formed retainers by an objective acoustic analysis of vowels and voiceless fricatives.

MATERIALS AND METHODS

Twenty adults, aged 19.0-29.0 years, who had just finished active orthodontic treatment were included in this study. They were divided into a Hawley retainer group and a vacuum-formed retainer group by sortation randomization method. The assessment of speech sounds was performed objectively using acoustic analysis before and after retainer application at the following time points: before wearing (T0), immediately after wearing (T1), and at 24 hours (T2), 1 week (T3), 1 month (T4), and 3 months (T5).

RESULTS

The production of /з:/, /i:/, /f/, /θ/, /s/, and /∫/ sounds for the Hawley retainer group and /i:/, /θ/, /s/, and /∫/ sounds for the vacuum-formed retainer group showed severe speech impairment according to acoustic analysis (P < .05). A comparison of the Hawley retainer group with the vacuum-formed retainer group revealed that the performance of /i:/, /f/, and /s/ sounds were significantly different (P < .05).

CONCLUSION

Although sound distortion could be found in both the Hawley retainer group and the vacuum-formed retainer group, changes in articulation were more obvious in the Hawley retainer group.

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

OBJECTIVE

In 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.

METHODS

A 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.

RESULTS

Twenty-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).

CONCLUSION

Further well-designed prospective studies are needed to elucidate the benefits and potential harms associated with orthodontic retainers.

Performance of clear vacuum-formed thermoplastic retainers depending on retention protocol: a systematic review

We aimed at comparing the performance of vacuum-formed thermoplastic retainers (VFR) worn either full-time or part-time, in maintaining orthodontic treatment results in terms of tooth alignment, arch form and occlusion. We reviewed randomized and prospective controlled clinical trials comparing VFR wearing protocols and searched databases, without restrictions, for published and unpublished literature. The risk of bias was assessed using the Cochrane Risk of Bias tool and the overall level of certainty in the evidence following ADA methodology. 184 studies were initially identified and reduced to the 3 randomized controlled trials included in the systematic review by means of specific criteria. One study followed patients 1 year into retention, and the other two for 6 months. Little's Irregularity Index, intermolar and intercanine width, arch length, overjet and PAR score did not differ significantly between the patients wearing their retainers part time or full time. We observed a slight increase in the overbite in the part-time group in only one trial. With a moderate level of certainty, we found that during the observation period, full-time VFR wear is not superior to part-time, bearing in mind the potential implications for health burden, retainer longevity and cost-effectiveness, as well as patient satisfaction and compliance.

Retention procedures for stabilising tooth position after treatment with orthodontic braces

BACKGROUND

Retention is the phase of orthodontic treatment that attempts to keep teeth in the corrected positions after treatment with orthodontic braces. Without a phase of retention, there is a tendency for teeth to return to their initial position (relapse). To prevent relapse, almost every person who has orthodontic treatment will require some type of retention.

OBJECTIVES

To evaluate the effects of different retention strategies used to stabilise tooth position after orthodontic braces.

SEARCH METHODS

We searched the following databases: the Cochrane Oral Health Group's Trials Register (to 26 January 2016), the Cochrane Central Register of Controlled Trials (CENTRAL) (2015, Issue 12), MEDLINE via Ovid (1946 to 26 January 2016) and EMBASE via Ovid (1980 to 26 January 2016). We searched for ongoing trials in the US National Institutes of Health Trials Register (ClinicalTrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform. We applied no language or date restrictions in the searches of the electronic databases. We contacted authors of randomised controlled trials (RCTs) to help identify any unpublished trials.

SELECTION CRITERIA

RCTs involving children and adults who had had retainers fitted or adjunctive procedures undertaken to prevent relapse following orthodontic treatment with braces.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened eligible studies, assessed the risk of bias in the trials and extracted data. The outcomes of interest were: how well the teeth were stabilised, failure of retainers, adverse effects on oral health and participant satisfaction. We calculated mean differences (MD) with 95% confidence intervals (CI) for continuous data and risk ratios (RR) with 95% CI for dichotomous outcomes. We conducted meta-analyses when studies with similar methodology reported the same outcome. We prioritised reporting of Little's Irregularity Index to measure relapse.

MAIN RESULTS

We included 15 studies (1722 participants) in the review. There are also four ongoing studies and four studies await classification. The 15 included studies evaluated four comparisons: removable retainers versus fixed retainers (three studies); different types of fixed retainers (four studies); different types of removable retainers (eight studies); and one study compared a combination of upper thermoplastic and lower bonded versus upper thermoplastic with lower adjunctive procedures versus positioner. Four studies had a low risk of bias, four studies had an unclear risk of bias and seven studies had a high risk of bias. Removable versus fixed retainers Thermoplastic removable retainers provided slightly poorer stability in the lower arch than multistrand fixed retainers: MD (Little's Irregularity Index, 0 mm is stable) 0.6 mm (95% CI 0.17 to 1.03). This was based on one trial with 84 participants that was at high risk of bias; it was low quality evidence. Results on retainer failure were inconsistent. There was evidence of less gingival bleeding with removable retainers: RR 0.53 (95% CI 0.31 to 0.88; one trial, 84 participants, high risk of bias, low quality evidence), but participants found fixed retainers more acceptable to wear, with a mean difference on a visual analogue scale (VAS; 0 to 100; 100 being very satisfied) of -12.84 (95% CI -7.09 to -18.60). Fixed versus fixed retainersThe studies did not report stability, adverse effects or participant satisfaction. It was possible to pool the data on retention failure from three trials that compared polyethylene ribbon bonded retainer versus multistrand retainer in the lower arch with an RR of 1.10 (95% CI 0.77 to 1.57; moderate heterogeneity; three trials, 228 participants, low quality evidence). There was no evidence of a difference in failure rates. It was also possible to pool the data from two trials that compared the same types of upper fixed retainers, with a similar finding: RR 1.25 (95% CI 0.87 to 1.78; low heterogeneity; two trials, 174 participants, low quality evidence). Removable versus removable retainersOne study at low risk of bias comparing upper and lower part-time thermoplastic versus full-time thermoplastic retainer showed no evidence of a difference in relapse (graded moderate quality evidence). Another study, comparing part-time and full-time wear of lower Hawley retainers, found no evidence of any difference in relapse (low quality evidence). Two studies at high risk of bias suggested that stability was better in the lower arch for thermoplastic retainers versus Hawley, and for thermoplastic full-time versus Begg (full-time) (both low quality evidence).In one study, participants wearing Hawley retainers reported more embarrassment more often than participants wearing thermoplastic retainers: RR 2.42 (95% CI 1.30 to 4.49; one trial, 348 participants, high risk of bias, low quality evidence). They also found Hawley retainers harder to wear. There was conflicting evidence about survival rates of Hawley and thermoplastic retainers. Other retainer comparisonsAnother study with a low risk of bias looked at three different approaches to retention for people with crowding, but normal jaw relationships. The study found that there was no evidence of a difference in relapse between the combination of an upper thermoplastic and lower canine to canine bonded retainer and the combination of an upper thermoplastic retainer and lower interproximal stripping, without a lower retainer. Both these approaches are better than using a positioner as a retainer.

AUTHORS' CONCLUSIONS

We did not find any evidence that wearing thermoplastic retainers full-time provides greater stability than wearing them part-time, but this was assessed in only a small number of participants.Overall, there is insufficient high quality evidence to make recommendations on retention procedures for stabilising tooth position after treatment with orthodontic braces. Further high quality RCTs are needed.

Truth or consequences: the potential implications of short-term cosmetic orthodontics for general dental practitioners

Until recently, cosmetic dentistry has focused on the use of traditional restorative techniques, bleaching and the so-called facial rejuvenators such as injectable dermal fillers and Botox. More latterly, the short-term use of aesthetic removable aligners and ceramic fixed appliance brackets have been promoted for use by general dental practitioners as a means of minimising the invasive amount of restorative dental treatment that would otherwise be required to achieve the desired degree of aesthetic improvement. Nevertheless, there are inherent risks and complications associated with short-term orthodontic treatments that are deliberately limited in their outcomes and these, together with the potential ramifications for the long-term dental health of patients, are discussed.

A new type of clear orthodontic retainer incorporating multi-layer hybrid materials

Clear thermoplastic retainers have been widely used in daily orthodontics; however, they have inherent limitations associated with thermoplastic polymer materials such as dimensional instability, low strength, and poor wear resistance. To solve these problems, we developed a new type of clear orthodontic retainer that incorporates multi-layer hybrid materials. It consists of three layers; an outer polyethylenterephthalate glycol modified (PETG) hard-type polymer, a middle thermoplastic polyurethane (TPU) soft-type polymer, and an inner reinforced resin core. The resin core improves wear resistance and mechanical strength, which prevent unwanted distortion of the bucco-palatal wall of the retainer. The TPU layer absorbs impact and the PETG layer has good formability, optical qualities, fatigue resistance, and dimensional stability, which contributes to increased support from the mandibular dentition, and helps maintain the archform. This new type of vacuum-formed retainer showed improved mechanical strength and rate of water absorption.

Removable cast chrome cobalt retainers for extended or indefinite period clinical use

Patients are frequently being asked to wear orthodontic retainers for as long as they want their teeth to remain in the post-treatment position. Fixed retainers, which are placed on the lingual surface of anterior teeth only, have the advantage of minimal compliance issues but are not without their problems related to wire fracture, adhesive failure and potential gingival or periodontal disease. Plastic retainers, although associated with relatively good aesthetics and compliance, have limitations related to their physical and mechanical properties. This paper describes a chrome cobalt metal retainer that could be used as a long-term retainer with few drawbacks. The properties of chrome cobalt are described and the clinical procedure is outlined.

Retention protocols and use of vacuum-formed retainers among specialist orthodontists

OBJECTIVE

To evaluate retention protocols and use of vacuum-formed retainers (VFRs) among specialist orthodontists.

DESIGN

Postal/electronic (e-) questionnaire.

SETTING

Republic of Ireland.

PARTICIPANTS

Members of the Dental Council of Ireland Specialist Register of Orthodontists and/or Orthodontic Society of Ireland.

METHODS

A pilot-tested questionnaire was distributed to 123 eligible specialist orthodontists. Questions addressed respondent demographics, preferred retainer choice in the maxillary and mandibular arches, prescribed wear protocols, VFR characteristics and factors influencing retainer choice. Statistical analyses were performed using PASW® version 18.

RESULTS

The response rate was 82%. VFRs were the most commonly chosen retainer, prescribed by 53% of respondents in the maxilla and 33% in the mandible. Full-time followed by part-time wear of removable retainers (RRs) was the wear protocol favoured by the majority (70-76%). Full occlusal coverage was the VFR design favoured by 93%. VFR sheet thicknesses of 1.0 mm (68%) and 0.75 mm (16%) were most commonly prescribed. Seventeen per cent were aware that their patients used their VFRs as a receptacle for dental bleaching gel. Life-time wear of retainers was advised by 67-78%. The operator factor that most influenced retainer choice was the pre-treatment situation (88%).

CONCLUSIONS

VFRs were the most common retainer choice in the maxilla and mandible with full-time wear followed by part-time wear of RRs favoured by most. Full occlusal coverage with a thickness of 1.0 mm was the VFR design prescribed by the majority. More than one in six specialist orthodontists were aware that their patients used their VFRs as a receptacle for dental bleaching gel.

Comparison of vacuum-formed and Hawley retainers: a systematic review

INTRODUCTION

Hawley retainers (HRs) and vacuum-formed retainers (VFRs) are the 2 most commonly used retainers in orthodontics. However, the basis for selection of an appropriate retainer is still a matter of debate among orthodontists. In this systematic review, we evaluated the differences between VFRs and HRs.

METHODS

Electronic databases (PubMed, EMBASE, Cochrane Library, ISI Web of Science, LILACS, and Pro-Quest) were searched with no language restriction. The relevant orthodontic journals and reference lists were checked for all eligible studies. Two article reviewers independently screened the retrieved studies, extracted the data, and evaluated the quality of the primary studies.

RESULTS

A total of 89 articles were retrieved in the initial search. However, only 7 articles met the inclusion criteria. Some evidence suggested that no difference exists to distinguish between the HRs and VFRs with respect to changes in intercanine and intermolar widths after orthodontic retention. In terms of occlusal contacts, cost effectiveness, patient satisfaction, and survival time, there was insufficient evidence to support the use of VFRs over HRs.

CONCLUSIONS

Additional high-quality, randomized, controlled trials concerning these retainers are necessary to determine which retainer is better for orthodontic procedures.

Anterior tooth alignment--recommendations for stability

This article considers the importance of current orthodontic practice in retention and stability when considering anterior tooth alignment.

CLINICAL RELEVANCE

With the exponential increase of general dentist-based orthodontic systems for anterior tooth alignment, with considerably shorter treatment times, practical recommendations along with a current literature review are required to improve success and outcome of the long-term result.