Removable Orthodontic Retainers Research Articles

Comparison of Various Mechanical Characteristics of Biostar Sheets with Heat-Cured Acrylic Resin

Background: Duran foil, a type of Biostar foil, is utilized in splint therapy as a heat-cure acrylic substitute material. The Duran® gained popularity and broad use, and its strength and resilience to wear are its most important qualities that improve splint therapy. This study aimed to investigate the surface roughness and fracture strength of heat-cured acrylic resin and Biostar sheets. Materials and Methods: A total of 20 samples—10 heat-cured acrylic resin samples and 10 biostar sheet samples—were produced and split into two groups in order to measure fracture strength and surface roughness. Results: The fracture strength of biostar samples had the lowest fracture strength. The surface roughness of the biostar samples was also less than that of the acrylic samples. There were statistically significant differences between the study groups. Conclusion Duran Biostar is regarded as the material of first choice for removable orthodontic retainers due to its suitable mechanical properties.

Comparison of speech changes caused by four different orthodontic retainers: a crossover randomized clinical trial.

This study aimed to compare the influence of four different maxillary removable orthodontic retainers on speech. Eligibility criteria for sample selection were: 20-40-year subjects with acceptable occlusion, native speakers of Portuguese. The volunteers (n=21) were divided in four groups randomized with a 1:1:1:1 allocation ratio. The four groups used, in random order, the four types of retainers full-time for 21 days each, with a washout period of 7-days. The removable maxillary retainers were: conventional wraparound, wraparound with an anterior hole, U-shaped wraparound, and thermoplastic retainer. Three volunteers were excluded. The final sample comprised 18 subjects (11 male; 7 female) with mean age of 27.08 years (SD=4.65). The speech evaluation was performed in vocal excerpts recordings made before, immediately after, and 21 days after the installation of each retainer, with auditory-perceptual and acoustic analysis of formant frequencies F1 and F2 of the vowels. Repeated measures ANOVA and Friedman with Tukey tests were used for statistical comparison. Speech changes increased immediately after conventional wraparound and thermoplastic retainer installation, and reduced after 21 days, but not to normal levels. However, this increase was statistically significant only for the wraparound with anterior hole and the thermoplastic retainer. Formant frequencies of vowels were altered at initial time, and the changes remained in conventional, U-shaped and thermoplastic appliances after three weeks. The thermoplastic retainer was more harmful to the speech than wraparound appliances. The conventional and U-shaped retainers interfered less in speech. The three-week period was not sufficient for speech adaptation.

Patient Compliance with Removable Orthodontic Retainers During Retention Phase: A Systematic Review

Patient Compliance with Removable Orthodontic Retainers During Retention Phase: A Systematic Review

The Effects of Fixed Versus Removable Orthodontic Retainers on Stability and Periodontal Health: 4-Year Follow-Up of a Randomized Controlled Trial.

Long-term or even indefinite retention is routinely prescribed after orthodontic treatment as a preventive safeguard against post-treatment changes induced by tooth movement, physiological healing, and the aging process. Though both fixed and removable versions of retainers may be equally effective in terms of results, sufficient research to support this assumption is missing at the moment. Long-term effects of fixed and removable retention on the periodontium, and the compliance level when used for an extended period of time. For 4 years participants were given a supply of canine-to-canine retainers and vacuum-formed canine-to-canine retainers. The inter-canine, as well as inter-molar widths, the length, and the extraction space opening of the mandibular anterior portion, were measured. Gingival inflammation, calculus, and plaque were observed, as well as the attachment of clinical and the case of bleeding during probing. 42 members had returned in the follow-up period, with 21 from each of the two groups. Measurements of the modified gingival index and plaque scoring were performed on the 10 intra-oral photographs that were taken at 4-week intervals in this study to investigate the intra-examiner reliability. After controlling for confounding variables, there was a 1.64 mm (95% confidence interval [CI], 0.30, 2.98 mm) median between-groups difference among patients who utilized vacuum-formed retainers (VFRs). The treatment groups did not vary in inter-canine and intermolar widths (P = 0.52; 95% CI, -1.07, 1.05), arch length (P = 0.99; 95% CI, -1.15, 1.14), or opening of extraction spaces (P = 0.84). A long-term study demonstrates that fixed retention can preserve the alignment of the mandibular anterior over time for the first time. Gingival discomfort and higher plaque scores were reported in both types of retainers.

Fixed and removable orthodontic retainers, effects on periodontal health compared: A systematic review.

A literature search was carried out by a reviewer by consulting PubMed, Lilacs, Embase, Medline full text, Scopus, Web of Science, Cochrane library, and Science Direct electronic databases for biomedical and health literature as well as the grey literature and setting up the search from December 2010 without any restriction about articles languages. The results showed that patients who wear retainers for a long period have significant differences in clinical parameters compared to patients without retainers. The type of retainer chosen also significantly influences the overall periodontal health of patients. Fixed retainers, both glass-fibre reinforced and steel wire retainers, proved to be the retainer type with the highest plaque and calculus accumulation values compared to removable retainers. In addition, among fixed retainers, glass-fibre reinforced retainers proved to be those that mostly promote the plaque and calculus accumulation in the application site. Fixed retainers are the best devices to maintain the alignment of mandibular anterior teeth in the long term. Among these devices, stainless steel lingual retainers, plain or braided, should remain the first choice. Although they are also susceptible to periodontal complications, their effect on periodontal health can be considered statistically insignificant if compared to glass-fibre reinforced retainers which, showing worse periodontal complications, should not be used.

Retraction: The Effects of Fixed Versus Removable Orthodontic Retainers on Stability and Periodontal Health: 4 Year Follow Up of a Randomized Controlled Trial.

[This retracts the article on p. S502 in vol. 15, PMID: 37654327.].

EFFECTS OF FIXED VS REMOVABLE ORTHODONTIC RETAINERS ON PERIODONTAL HEALTH

Objective: To assess the effects of fixed and removable orthodontic retainers in a mandibular arch on periodontal health. Methodology: This study was carried out at AFID from November 2018 to November 2020. Sixty-four patients, 42 females (65%) and 22 males (34%) with a mean age of 19.46±2.01years were selected and given either vac­uum formed retainer (VFR) or bonded retainer wire (BRW) in mandibular arch and divided into two equal groups. Only the mandibular arch was used to measure two clinical variables (Gingival index and calculus index) at four different time intervals, immediately after de-bonding (T0), at 6 months (T1), at 12 months (T2) and at 24 months(T3) to assess the effects of two retainer groups on Periodontal health. Results: No significant difference was found between gingival index and calculus index scores at T0 among VFR group and BRW group (p>0.05) while statistically significant differences were found in gingival index scores at T1 (p=0.025) and calculus index scores at T1 and T3 (p=0.015, p=0.048 respectively) among the two retainer groups. Conclusion: Fixed bonded retainer wire is capable of causing gingival inflammation and calculus aggregation, indicated by mild increase in gingival and calculus scores, in comparison to vacuum formed retainer. Although no adverse effects were observed on overall periodontal health with both retainers. This does not guarantee future disease progression, so careful monitoring of oral hygiene on follow-up visits should be a prime concern of ortho­dontists.

Effects of Hawley, Essix, and Vivera® retainers on salivary properties, oral hygiene, and Streptococcus mutans levels: A prospective clinical pilot study

Objectives: The objectives of the study were to investigate the in vitro and in vivo effects of various removable orthodontic retainer materials on clinical and microbiological parameters, specifically on saliva characteristics, oral hygiene, and salivary levels of Streptococcus mutans (S. mutans). Materials and Methods: This study consists of two parts: An in vitro study and in vivo prospective clinical pilot study. The in vitro study measures surface roughness and S. mutans adhesion of three orthodontic retainer materials: Polymethylmethacrylate (PMMA) used in traditional Hawley removable retainers, polypropylene (PP), and polyurethane (PU) used in vacuum-formed retainers. In the clinical pilot study, 20 subjects, on completion of orthodontic treatment were randomized into three groups to receive PMMA, PP, or PU removable orthodontic retainers. They were compared with control subjects with no orthodontic treatment and retainers. Quantitative analysis of salivary S. mutans using real-time polymerase chain reaction was performed to screen for differences during retainer issue (T0) and 8–15 weeks later (T1). Salivary flow rate, pH, buffering capacity, and plaque scores were also recorded at these two periods for comparison. Results: PMMA had significantly greater surface roughness and S. mutans adhesion than PP and PU (P = 0.027). The PMMA group displayed significantly greater amounts of salivary S. mutans count when compared to the PP (0.001) and PU (P = 0.011) groups. Conclusion: PMMA retainers showed increased S. mutans adhesion and intra-oral colonization of S. mutans compared to PP and PU retainers. The results validate further clinical testing for a relationship between caries risk and type of retainer prescribed.

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.

Development of ‘My Retainers’ mobile application: Triangulation of two qualitative methods

ObjectiveDiligent wear of removable orthodontic retainers requires prolonged adherence and is invariably necessary to preserve optimal results. Patient-informed behaviour-change interventions represent a promising and novel means of enhancing adherence to removable retainer wear. The aim of this study was to describe the development of a patient-informed mobile application designed to enhance retainer wear. MethodsApp development encompassed consideration of participant preferences, social media posts, available interventions and behaviour change theories. Qualitative methods including analysis of publicly-available retainer-related posts on Twitter (n = 827) and one-to-one interviews were undertaken. Audio-recorded one-to-one interviews were undertaken to identify patient preferences in relation to features, content and design of the application. A criterion-based purposive sample of participants wearing vacuum-formed retainers for at least 4 years was used (n = 15). Thematic analysis of transcribed data was undertaken. These data were triangulated to inform design and content of the application. ResultsThe need to facilitate communication with the treating clinician, responsive reminder and tracking systems, and access to useful and engaging written and visual information, in addition to other personalised and interactive features were considered important. Concerns related to retainer wear shared on Twitter informed an exhaustive list of frequently-asked questions. Application features were mapped to relevant theoretical constructs. Determinants of existing behavioural change theories were also used to link application features to retainer wear and maintenance. ConclusionsA holistic process involving both patient and professional input can be useful in informing the development of mobile applications. The orthodontic application ("My Retainers") will undergo further scrutiny in relation to its effectiveness in inducing behavioural change and concerning patient experiences prior to finalisation.

Comparative evaluation of salivary microbial levels and periodontal status of patients wearing fixed and removable orthodontic retainers.

The purpose of this study was to compare and evaluate salivary microbial levels and periodontal status in patients using a fixed lingual retainer, a removable vacuum-formed retainer, or a Hawley retainer after orthodontic treatment with fixed appliances. Forty-five patients who finished their orthodontic treatment with fixed appliances and were about to start the retention phase were randomly divided into the following 3 groups of 15 individuals each: the fixed lingual retainer group, the vacuum-formed retainer group, and the Hawley retainer group. Periodontal measurements, such as the plaque index, gingival index, probing depth, and bleeding on probing, were obtained at the following 4 time points: at debonding (T0) and 1week (T1), 5weeks (T2), and 13weeks (T3) after debonding. Saliva samples were collected 3 times in total: at T0, T2, and T3. A quantitative analysis for Streptococcus mutans and Lactobacillus casei was performed with the use of real-time polymerase chain reaction. The Kruskal-Wallis test and 1-way analysis of variance were used for the statistical comparisons of the groups. No statistically significant difference in salivary S mutans and L casei levels was found among the 3 groups (P>0.05). They showed no statistically significant differences in plaque index, gingival index, bleeding on probing, and probing depth values (P>0.05). All periodontal parameters showed statistically significant decreases from T0 to T3 in all 3 groups (P<0.001). The S mutans and L casei levels were decreased significantly from T2 to T3 in the lingual retainer and Hawley retainer groups, whereas they decreased significantly from T0 to T3 in the vacuum-formed retainer group. Fixed and removable orthodontic retainers do not differ in salivary S mutans and L casei levels and periodontal status. With all retainers, regardless of whether they are fixed or removable, oral hygiene improved after orthodontic treatment with fixed appliances.

Users' perceptions and preferences towards maxillary removable orthodontic retainers: a crossover randomized clinical trial.

The aim of this study was to assess, correlate, and compare users' perceptions and preference related to maxillary removable retainers. Volunteers were recruited to use four retainer types: conventional wrap-around (CWA), wrap-around with an anterior opening (OWA), "U" wrap-around (UWA), and clear thermoplastic retainer (CT). The main outcomes were the volunteers' perceptions, evaluated with a 100-mm visual analogue scale, and their preferred retainer. The retainers were used for 21 days each (washout intervals of 7 days). Nineteen volunteers (27 ± 4.53 years) were randomly divided into four groups that used the four retainers, but with a different sequence. Perceptions were evaluated immediately after the use of each retainer and the preference at the end of the research. Repeated measures ANOVA and Friedman tests with post-hoc Tukey's test (intergroup comparisons), and Pearson and Spearman analyses (correlations between perceptions) were applied. The WA retainers did not significantly differ among themselves. The CT was rated significantly worse in speech (p ≤ 0.001), discomfort (p < 0.001), and occlusal interference (p < 0.001), and did not significantly differ from the others in esthetics. Users preferred significant more the WA retainers in comparison with the CT retainers. The occlusal interference caused by the CT was positively correlated to other perceptions, such as changes in speech and discomfort. WA retainers presented similar preference and perceptions, but were significantly better than the CT. The CT occlusal coverage appeared to be the primary cause of its rejection.

Fixed and removable orthodontic retainers and periodontal health.

Data sourcesMedline, PubMed, Cochrane Central Register of Controlled Trials, LILACS and BBO databases with no language restrictions; unpublished literature was searched in Proquest Dissertations and Theses database, clinicaltrials.gov and controlled-trials.com.Study selectionRandomised and nonrandomised controlled clinical trials, prospective cohort studies, and case series (with a minimum sample size of 20 patients) in patients who underwent fixed or removable appliance orthodontic therapy with a minimum follow-up period of six months. The primary outcome was periodontal health; while failure rates, impact of orthodontic retainers on patient-reported outcomes and cost-effectiveness served as secondary outcomes.Data extraction and synthesisFull texts of relevant abstracts were retrieved and data extracted using pre-piloted data collection forms by two authors. Study quality was assessed with Cochrane Collaboration's Risk of Bias tool (RCTs) and Newcastle-Ottawa Scale (NOS) for non-randomised studies. Only RCTs at low or unclear risk of bias and non-randomised studies of moderate or high methodological quality were included in the meta-analysis (MA). If moderate to high heterogeneity was present (I2 > 50%), MA was not performed.ResultsOut of the 18 included RCTs, 11 were assessed to be of low risk of bias while five out of six prospective cohort studies were considered high quality using the NOS. The authors did not perform MA because of significant heterogeneity that existed among different studies.With regards to periodontal health, there was no significant difference in probing depth and bleeding on probing between fixed mandibular stainless steel (SS) retainers (bonded to anterior teeth or canines only), fibre reinforced composite retainers or Hawley retainers at three-year follow-up. However, there was increased plaque accumulation around fibre reinforced composite retainers compared to SS retainers. The failure rates of mandibular stainless steel fixed retainers bonded from canine to canine was 0.29 (95 % confidence interval [CI], 0.26, 0.33) over a follow-up period of six to 36 months. The failure risk for mandibular stainless steel fixed retainers bonded to canines only was 0.25 (CI, 0.16, 0.33) over a follow-up period of one to three years. A meta-regression showed that follow-up period was not a predictor of failure rate for mandibular stainless steel fixed retainers. The failure rates of removable retainers (Hawley's or vacuum formed retainers) are lower than the bonded fixed retainers. Removable Hawley's retainer was associated with increased discomfort as well as higher levels of embarrassment with speech and aesthetics. In terms of cost-effectiveness, vacuum-formed retainers were found to be significantly more cost-effective than Hawley retainers or mandibular stainless steel fixed retainers bonded to canines.ConclusionsThere is a lack of high-quality evidence to endorse the use of one type of orthodontic retainer based on their effect on periodontal health, risk of failure, patient-reported outcomes and cost-effectiveness.

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

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

The influence of surface roughness and surface dynamics on the attachment of Methicillin-Resistant Staphylococcus aureus onto orthodontic retainer materials.

Staphylococci species have been isolated from removable orthodontic retainers. The aims of this study were to determine the most suitable device to analyze surface roughness of autopolymerized acrylic and thermoplastic materials and whether the surface dynamics of these materials influences the attachment of Methicillin-Resistant Staphylococcus aureus (MRSA). Clinically simulated samples of autopolymerized acrylic and thermoplastic material were first evaluated using laser non-contact, stylus mechanical profilometries and atomic force microscopy (AFM) followed by contact angle measurement to characterize their surface dynamics. Finally, an in vitro biofilm assay was carried out using a constant depth film fermentor to assess biofilm attachment. The results showed a significant difference between the roughness values obtained from the tested profilometers with the AFM exhibiting the most consistent roughness values. MRSA tended to accumulate initially within the microscopic irregularities of autopolymerized acrylic samples whereas acid-base and electron donor interactions influenced the bacterial attachment onto the thermoplastic samples.

No statistically significant results for two removable orthodontic retainers

Randomised controlled trial. Participants were randomly assigned to receive either a Hawley retainer (HR) or a clear overlay retainer (COR). The HR was composed of a 2 mm-thick acrylic resin base plate, one-arm clasps with 0.9 mm-diameter stainless steel wire on the first molars, and a Hawley bow with 0.7 mm stainless steel wire. The COR was made from a 0.75 mm-thick thermoplastic material with the buccal edge paralleling the gingival margin, the lingual portion extending 4 to 5 mm beyond the lingual gingival margin. Distally the second molars were covered. Both groups of patients were required to wear the retainers full-time, except during meals and were followed for one year. Retainer survival was the primary outcome. Small surface cracks were not considered as a breakage unless the retainers could not be worn because of crack expansion. One hundred and twenty patients were randomised, 61 in the HR group, 59 in the COR group, nine patients (five in the HR group and four in the COR group) were lost to follow up. Fracture was the most often cited reason for breakage, followed by retainer loss. No significant differences were seen in survival times between the two groups. Both retainers tended to fracture, but the fracture locations were different. This analysis suggests that the survival times of the HRs and CORs were not statistically significantly different. Therefore, clinicians could advise their patients to wear either of the two retainers without taking breakage into consideration.

In Situ Effect of 10% Carbamide Peroxide on Microhardness of Human Enamel: Function of Time

This study evaluated the effect of two home bleaching regimens (1 h/day versus 7 h/day for a total of 21 days) on the microhardness of superficial enamel treated with 10% carbamide peroxide gel. Rectangular enamel specimens (2.5 x 2.5 x 1 mm) were obtained from human third molars and mounted on the palatal aspect of removable orthodontic retainers. Nine enamel specimens were mounted in each of 10 retainers, used by 10 volunteers during the active phase of the study. Modified 0.089 cm thick bleaching trays were fabricated for each participant. Each bleaching tray fit a participant's arch and the retainer containing the enamel specimens. Enamel specimens were treated with a 10% carbamide peroxide bleaching gel (Nite White Excel 2Z, Discus Dental, Culver City, CA, USA) for either 1 h/day (n = 30) or 7 h/day (n = 30), both for 21 days. Three enamel specimens in each retainer were never treated and served as controls. The retainers were worn by the participants whether or not they underwent bleaching. This simulated the natural action of the saliva/oral fluids on the enamel specimens. Enamel specimens were subjected to pre- and post-treatment microhardness measurements. Post-treatment Knoop hardness numbers were compared with baseline values and analyzed statistically. Bleaching treatment resulted in a nonsignificant reduction in microhardness values when compared with values of the control nontreated specimens (1.7% and 2.5% reduction in hardness for 1 h/day and 7 h/day, respectively). There was no difference in microhardness between the different treatment regimens. Home bleaching with 10% carbamide peroxide for up to 7 h/day for 21 days does not significantly affect enamel microhardness. Bleaching with 10% carbamide peroxide for 1 h/day or 7 h/day for a total of 21 days is safe for human enamel.

Oral lesions caused by an orthodontic retainer: A case report

Jetainers are mostly used at the end of the active phase of orthodontic treatment to stabilize the teeth for extended periods of time. Retainers can be either fixed or removable. Removable orthodontic retainers, such as Hawley appliances, are made of an acrylic body and also incorporates stainless steel wires that are used for constructing the labial bow and the retention clasps. The ends of the labial bow are often bent to cross the occlusal table and get embedded in the