Periodontal implications of bonded versus removable retainers

Poly-Ether-Ether-Ketone versus dead-soft coaxial bonded retainers: a randomized clinical trial. Part 2: periodontal health and microbial biofilm assessment

BACKGROUND

Retainers have the potential to detrimentally impact periodontal health and contribute to tooth decay.

OBJECTIVES

To investigate periodontal health and bacterial biofilm related to Poly-Ether-Ether-Ketone (PEEK) fixed retainers as compared to Dead-soft coaxial fixed retainer (DSC).

TRIAL DESIGN

A two-arm parallel groups single-centre randomized clinical trial.

METHODS

The trial included patients whose orthodontic treatment was completed and required retainers. Participants were randomly assigned into two retainer groups: PEEK retainers, prepared by computer-aided design and manufacturing into 0.8 mm wire form, and DSC retainers. The objectives included assessing periodontal health through plaque accumulation index (PI), bleeding on probing (BOP), periodontal pocket depth (PPD), gingival index (GI), calculus index (CI), and alveolar bone height (ABH) assessment. Biofilm assessment involved bacteriological screening of aerobic, facultative anaerobic, mutans streptococci, and lactobacilli. The periodontal indices and microbiological screening as well as were assessed at the debonding stage (T0), 1-month (T1), 3-month (T3), and 6-month (T6) after the commencement of the trial, except for the ABH, which was recorded using periapical radiograph at T0 and T6.

BLINDING

Single blinding of participants in addition to the bacteriological specialist.

RESULTS

Initially, the trial enrolled 46 participants, aged between 12 and 28 years, and were randomly assigned to two groups, with 23 participants in each group. Subsequently, one participant withdrew from the trial, resulting in a total of 45 participants whose data were analysed. Assessment of the periodontal indices, excluding the CI (P = .480), revealed statistically but not clinically significant differences between groups after 6-month of retention (P = .016 of PI, P = .020 of BOP, P = .05 of PPD, and P = .01 of GI). There was slight plaque accumulation, normal PPD (approximately 1 mm), healthy to mild gingivitis with a GI of less than 1 and BOP was around 10%. Concerning the ABH, there was a noticeable reduction in its score after 6 months, particularly in the PEEK group, although the difference was not statistically significant (P = .102). Furthermore, the bacteriological viable count did not show any significant difference between the groups during the recall visits.

HARMS

There have been no reported negative consequences.

LIMITATIONS

Blinding the assessor of periodontal indices was not feasible due to the nature of the intervention. The trial follow-up duration was limited.

CONCLUSIONS

Both the PEEK and DSC retainers have comparable impacts on periodontal health and bacterial accumulation and composition during the retention period.

TRIAL REGISTRATION

NCT05557136.

Influence of fixed orthodontic steel retainers on gingival health and recessions of mandibular anterior teeth in an intact periodontium - a randomized, clinical controlled trial

OBJECTIVE

Aim of this randomized clinical controlled trial was to evaluate the influence of fixed orthodontic steel retainers on gingival health and recessions of mandibular anterior teeth.

MATERIALS AND METHODS

After end of the orthodontic treatment, patients were randomly assigned into the test (fixed steel retainer) or control group (modified removable vacuum-formed retainer). Periodontal parameters (periodontal probing depth: PPD; recession: REC; bleeding on probing: BOP) as well as plaque and gingival index were assessed on mandibular anterior teeth directly before attaching/handing over the retainer (baseline: BL), 6 and 12 months after orthodontic treatment.

RESULTS

37 patients (test: n = 15, mean age: 16.1±4.2 years; control: n = 17, mean age: 17.1±5.4 years) completed the study. REC and PPD failed to show significant pairwise differences. The number of patients showing gingival health in the area of the mandibular anterior teeth (test: BL n = 10, 6 months n = 9, 12 months n = 11; control: BL n = 10, 6 months n = 16, 12 months n = 15) revealed a significant difference for the intra-group comparison between BL and 6 months in the control group (p = 0.043). The inter-group comparisons failed to show significant differences.

CONCLUSION

Young orthodontically treated patients with fixed steel retainers show in 73.3% healthy gingival conditions after one year which are comparable to the control group (88.2%). Gingival recessions were in a clinically non-relevant range at any time of the examination.

CLINICAL TRIAL NUMBER

DRKS00016710.

Effect of splinting material type and location on resistance against deflection force of splinted periodontally compromised teeth with hypermobility

This study aimed to evaluate the effect of splinting material type and material location on the force resistance of splinted periodontally compromised teeth with hypermobility. Extracted teeth including the target tooth (maxillary second premolar) and its adjacent teeth were placed into the alveolar sockets of a dental arch model via artificial periodontal ligaments made of elastic impression material. Three different experimental models with varied target tooth mobility including Periotest® values (PTVs) of 20, 30, and 40 were fabricated (named models #20, #30, and #40, respectively). For each experimental model, the force resistance of tooth splinting was tested using the following four materials: everStick PERIO (glass fiber reinforcement: GFR), FORESTAFLEX (braided stainless steel: BSS), Ortho-FlexTech (stainless steel chain: SSC), and Super-Bond (MMA-based resin cement: MRC). The evaluated measures were the PTV after tooth splinting and the required load to cause tooth displacements of 0.05 mm and 0.10 mm in the vertical and lateral directions, respectively. The splinting material type and material location as well as the original PTV of target the tooth significantly affected all the evaluated measures (p < 0.001). MRC revealed the significantly highest force resistance of tooth splinting regardless of material location in each experimental model and was followed by GFR. The PTVs of splinted teeth were comparable to those of adjacent anchor teeth in models #20 and #30 when using GFR, while that was comparable in model #40 when using MRC. Meanwhile, the load causing certain tooth displacement showed a similar tendency to previous-reported data with healthy teeth in model #20 when using GFR, while that showed a similar tendency in models #30 and #40 when using MRC. Overall results concluded that splinting material type and location play a role in the resistance against the deflection force of splinted periodontally compromised hypermobile tooth. It was noted that MRC provided the highest resistance against the deflection force of splinted teeth regardless of material location whereas GFR maintained the physiologically considered tooth mobility.

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

The aim of this systematic review is to analyze the properties of the different types of orthodontic retainers, identify their differences and define which type of device is most effective and less harmful to periodontal health.

Methods

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.

Results

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.

Conclusion

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.

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 multistranded wire and fiber-reinforced composite retainers effects on periodontium: A randomized clinical trial

INTRODUCTION

Fixed orthodontic retainers are very important for treatment stability; however, adverse effects on the health of periodontium can be caused as a result of deposition of plaque and calculus.

OBJECTIVES

To compare and determine the effects of two mandibular fixed lingual retainers on the periodontal status, and to test the null hypothesis that there would be no significant difference on the periodontium health between the patients using fiber-reinforced composite (FRC) or multistranded wire (MSW) fixed retainers.

METHODS

A total of 60 subjects were recruited, out of which 6 were excluded and 2 dropped out during the study. Hence, 52 subjects with mean age of 21.5 ± 3.6 years were included in the study. The sample was composed by 8 males (15.4%) and 44 females (84.6%). The participants were randomly divided into two groups: Group 1 received fiber-reinforced composite retainer, while Group 2 received multistranded wire retainer. After insertion, plaque index, calculus index, gingival index and bleeding on probing were compared, after three months (T1), six months (T2), nine months (T3) and twelve months (T4), using Mann-Whitney test with p-value ≤ 0.05 as significant.

RESULTS

It could be seen that the health of periodontium deteriorated with the passage of time from T1 to T4 in both group of retainers. However, no statistically significant differences were found between the two groups (p> 0.05).

CONCLUSION

The results of the study indicate that there was no significant difference on the health of periodontium between the patients with FRC and MSW fixed retainers, hence, the null hypothesis was accepted.

Periodontal status in long-term orthodontic retention patients up to 10 years after treatment - a cross-sectional study

OBJECTIVE

To assess periodontal status in long-term orthodontic retention patients and investigate possible risk indicators.

MATERIALS AND METHODS

Plaque index (PI), gingival index (GI), probing pocket depth (PPD), gingival recessions (GR) and calculus were recorded in 211 patients with or without fixed retainers.

RESULTS

Periodontal parameters were within the limits of clinically healthy periodontium. The use of fixed retainers was associated with higher PI in the maxilla (ß = 1.10 [0.37]; p <.05). Older age was associated with higher PI in the mandible (ß = 0.27 [0.11]; p <.05). Smoking was associated with gingival bleeding on both palatal (ß = 0.63 [0.16]; p < .01) and labial sides in the maxilla (ß = 0.46 [0.20]; p <.05). Smoking was also associated with increased prevalence of GR in the mandible (ß = 0.24 [0.07]; p <.01), while use of snuff had similar effect on the labial side in the maxilla (ß = 0.35 [0.08]; p <.01). Higher age (ß = 0.05 [0.02]; p <.05) and the presence of a retainer (ß = 0.23 [0.07]; p < .05) were associated with calculus accumulation on the lingual side in the mandible.

CONCLUSION

The present observational study suggest that long-term fixed retainers alone have no detrimental effect on the periodontium. Additional factors may increase the risk of plaque deposits and increased probing pocket depths. Further prosepective studies are needed to confirm the present outcome.

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.

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

INTRODUCTION

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.

METHODS

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 1 week (T1), 5 weeks (T2), and 13 weeks (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.

RESULTS

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.

CONCLUSIONS

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.

Periodontal parameters of two types of 3 x 3 orthodontic retainer: a longitudinal study

INTRODUCTION

bonded fixed retainers are often used to stabilize the results obtained with the orthodontic treatment. It is important that they do not prejudice dental health, as they will be used for a long period.

OBJECTIVE

The purpose of the present study was to compare periodontal indexes between two types of bonded fixed retainers, conventional 3 x 3 plain retainer (0.8-mm orthodontic wire, bonded to the canines only) and a manufactured braided retainer (0.2 x 0.7-mm stainless steel wire, bonded to all anterior teeth) after use.

METHODS

a test group of 15 volunteers (aged from 18 to 25 years) used both the conventional retainer and braided retainer for six months. A randomized longitudinal study design, with a two week washout interval, was applied. The dental plaque index, gingival index and dental calculus index were evaluated. Furthermore, the calculus accumulated along the retainer wire was measured and all patients answered a questionnaire about the use, acceptance and comfort of both types of retainers.

RESULTS

the scores for plaque and gingival indexes were higher for the braided retainer (p< 0.05) on the lingual and proximal surfaces. The same occurred with the calculus index on the lingual surfaces (p< 0.05). The calculus index along wire was higher for the braided retainer (p< 0.05). All patients preferred the conventional retainer, and said that it was also more comfortable to use.

CONCLUSION

it was concluded that the conventional retainer showed better periodontal indexes than the braided type.

Fixed Orthodontic Retainers: A Review

Orthodontic retention is defined as maintaining teeth in optimal aesthetic and functional position after treatment. Despite the necessity of retention phase and the factors influencing the stability of the teeth after orthodontic treatment was discussed by the orthodontist for a long time, it is accepted that a retention phase is essential for stability of orthodontic treatment results nowadays. Therefore, the application of a suitable retention method is important both for prevention of relapse after orthodontic treatment and for increasing patient satisfaction. Removable appliances had been used for many years for retention purposes. Later, fixed retainers were introduced to prevent relapse as having a number of advantages, such as better aesthetics, no need for patient cooperation, effectiveness, and suitability for lifelong retention. However, their need for precise bonding technique, fragility, and tendency to cause periodontal problems by weakening oral hygiene are some of their disadvantages.

Biomechanical properties of CAD/CAM-individualized nickel-titanium lingual retainers: an in vitro study

PURPOSE

This study aimed to determine and compare the mechanical properties of novel CAD/CAM(computer-aided design/manufacturing)-individualized nickel-titanium (NiTi) and conventional twisted wires.

METHODS

Seven NiTi wires (angular, 0.20 × 0.20 mm up to 0.50 × 0.50 mm) and two twisted steel wires (round, 0.40 mm and 0.44 mm) were investigated in three-point (3PBT) and four-point bending tests (4PBT) using the Orthodontic Measurement and Simulation System. All wires were loaded up to a distance of 3.3 mm, and resulting forces were measured. Additionally, in the biomechanical test (BMT), CAD/CAM-individualized NiTi retainers (0.35 × 0.35 mm) were subjected to intrusive and extrusive deformation of 0.1, 0.2, and 0.4 mm.

RESULTS

For twisted wires, typical plastic deformations were found in 3PBT (0.40 mm: 0.3 mm; 0.44 mm: 0.4 mm), and maximum resulting forces for these reached 1.3 N and 3.2 N for the 0.40 mm and 0.44 mm wires, respectively. Corresponding values in the 4PBT totaled 0.8 N for the 0.40 mm and 1.9 N for the 0.44 mm twisted wire. The NiTi samples showed plastic deformations in the 3PBT for the 0.25 × 0.25 mm dimension and in 4PBT for the 0.35 mm × 0.35 mm version. At a deflection of 1.5 mm, both tests revealed significantly different forces for the NiTi wires of different dimensions (p ≤ 0.001). In the BMT, no remarkable loading plateau or plastic deformation was observed. The resulting forces were significantly higher for extrusive than for intrusive deformation (p ≤ 0.001).

CONCLUSIONS

Individualized NiTi retainers feature specific elasticity and dimensional stability, and more deflection is necessary to achieve permanent deformations. The CAD/CAM production process did not significantly influence the biomechanical properties of the NiTi wires.

Periodontal health and compliance: A comparison between Essix and Hawley retainers

INTRODUCTION

Many studies on removable retainers have focused on retention efficacy and characteristics. However, studies on plaque accumulation, periodontal health, breakages, and patient compliance are still lacking. Thus, in this study, we aimed at evaluating these parameters in 2 groups of young patients wearing Essix or Hawley retainers for a 6-month period.

METHODS

Seventy subjects were included. Periodontal health was investigated by measuring the plaque, gingival, calculus, and bleeding on probing indexes. Evaluations were performed at 1, 3, and 6 months of wearing. Accumulation of plaque on the retainers was also evaluated. Furthermore, compliance on wearing retainers and breakage data were collected by specific questionnaires.

RESULTS

Subjects wearing Essix retainers had significantly higher levels of plaque, gingival, and calculus indexes and increased percentages of bleeding sites, compared with subjects wearing Hawley retainers. The Essix group also had increased accumulations of plaque and calculus on the retainers. Nonetheless, subjects of the Essix group had better overall experiences, self-perceptions, and comfort compared with those of the Hawley group. Essix retainers had higher incidences of little and serious breakages compared with Hawley retainers.

CONCLUSIONS

Our results suggest that Essix retainers are well accepted by patients for their esthetic and oral comfort characteristics. However, Essix retainers may cause greater accumulations of plaque on both teeth and retainers, presumably because of inhibition of the cleaning effect of saliva caused by the thermoplastic material or the reduced opportunity for good hygiene on the retainer.

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.

An in vivo spectrophotometric evaluation of Vivera® and Essix® clear thermoplastic retainer discolouration

Aim

To assess the in vivo colour alterations of two different clear thermoplastic retainers.

Methods

Thirty patients were randomly allocated into two Groups (N = 15) following the completion of active orthodontic treatment. Group 1 received Vivera® and Group 2 Essix® C+ thermoplastic retainers. Each patient was provided with two fabricated retainers (one for use and the other to serve as a control). The CIELAB parameters of the patients’ upper central incisors were measured with a SpectroShade™ spectrophotometer immediately after retainer placement (T0) and again after 15 days (T1), one month (T2) and three months (T3). The measurements were also performed on teeth without the retainer in place. ΔE differences were calculated.

Methods

ΔE changes from T0 to Tp T2 or T3 showed no statistically significant differences between Groups 1 and 2 within any combination of measurements or teeth. ΔEļŢ3-Ţ0ļ changes for used retainers were 1.55 times higher than control appliances (p = 0.002) and 1.44 times higher than for teeth-only (p = 0.004). For used retainers, changes between T3 and T0 were 1.56 times higher than between T and T0 and 1.47 higher than between T2 and T0 (p < 0.001). There were no statistically significant differences in ΔE between teeth 11 and 21.

Results

Used retainers exhibited greater colour change than control appliances or teeth-only readings, and increased commensurate with the duration of use. Vivera® and Essix® retainers exhibited similar colour stability. All differences observed were considered clinically acceptable (ΔE < 3.7), although prolonged use could cause clinically significant colour changes.

Effects of vacuum-formed retainers on periodontal status and their retention efficiency

INTRODUCTION

The stability of treatment results is a major concern in orthodontics. Numerous retention regimens to maintain stability have been introduced. The objectives of this study were to evaluate the effects of vacuum-formed retainers (VFRs) on periodontal tissues and the retention efficiency of VFRs.

METHODS

Forty patients were included in this study. Clinical effectiveness of VFRs for nighttime use only over a 12-month period was assessed by using the American Board of Orthodontics' Objective Grading System. Periodontal measurements and indexes were recorded and evaluated immediately after removal of the braces and after 1, 6, and 12 months of VFR use.

RESULTS

There was no significant change in the total Objective Grading System score between the end of the active treatment period and the end of the 12-month retention period. However, regarding periodontal measurements, the plaque and gingival indexes decreased, whereas the bleeding on probing, probing depth, calculus index, and clinical attachment loss increased between the evaluated periods.

CONCLUSIONS

In terms of periodontal health, the use of VFRs resulted in a slight periodontal attachment loss that seemed to be clinically insignificant, without gingival inflammation or recession. In terms of stability, VFRs were found to be effective in orthodontic retention.

Gingival condition associated with two types of orthodontic fixed retainers: a meta-analysis

Background

The maintenance of gingival health around orthodontic fixed retainers (FRs) is difficult and different designs have been proposed.

Objective

The goal of this systematic review was to analyse whether FR designs that allow unobstructed interproximal flossing, compared with the ones that do not, improve gingival parameters.

Search methods

Detailed individual database search strategies for Cochrane Library, 'Latin' American and 'Caribbean' Health Sciences Literature, PubMed, Scopus, and Web of Science were developed. Grey literature was also considered.

Selection criteria

Clinical trials and cross-sectional studies that compared two types of FRs (plain and waved) were included and evaluated.

Data collection and analysis

Study selection, data extraction, and risk of bias (RoB) assessment were performed individually and in duplicate. The methodology quality was assessed using the MAStARI RoB tool.

Results

Four studies met the inclusion criteria, and all presented moderate RoB. While two of those studies found a statistically significant difference in gingival parameters, the other two did not report differences. A meta-analysis was conducted based on two of the selected studies, which performed evaluations of plaque index (PI) and calculus index (CI). The results revealed no differences on PI between wave FR and plain FR of 0.46 (0.24 to 0.69) and no differences on CI of 0.12 (-0.10 to 0.33). Regarding comfort, no clear differences were identified.

Conclusions

There is not enough scientific evidence to support or not an association between FR design and gingival health, flossing frequency, or patient comfort.

Registration

PROSPERO - CRD42016030059.

Retrieval analysis of lingual fixed retainer adhesives

INTRODUCTION

Our objective was to analyze the surface and bulk properties alterations of clinically aged composites used for fixed retention.

METHODS

Twenty-six lingual retainers bonded for different time periods (2.2-17.4 years) were retrieved from postorthodontic patients. Fifteen lingual retainers had been cemented by a chemically cured adhesive (Maximum Cure, Reliance Orthodontic Products, Itasca, Ill), and 11 were treated with a photo-cured adhesive (Flow-Tain, Reliance Orthodontic Products). The first group was in service for 2.8 to 17.4 years and the second for 2.2 to 5.4 years. Five specimens from each material were prepared and used as the control (or reference) group. The debonded surfaces from enamel were studied by attenuated total reflectance Fourier transform infrared spectroscopy (n = 3 per material per group), low-vacuum scanning electron microscopy, and energy dispersive x-ray microanalysis (n = 3 per material per group). All specimens were used for the assessment of Vickers hardness, indentation modulus, and elastic index with the instrumented indentation testing method. The values of Vickers hardness, indentation modulus, and elastic index were compared between the retrieved and the reference groups with 1-way analysis of variance and the Student-Newman-Keuls multiple comparison test (α = 0.05).

RESULTS

The attenuated total reflectance Fourier transform infrared spectroscopy analysis showed that both retrieved composites demonstrated reduced unsaturation in comparison with the corresponding reference specimens. Some bonded surfaces showed development of organic integuments. All retrieved specimens showed reduced silicon content. Barium was identified only in the photo-cured group. No significant differences were found between the reference and retrieved groups in Vickers hardness, indentation modulus, and elastic index.

CONCLUSIONS

Despite the changes in composition, the mechanical properties of the materials tested remained unaffected by intraoral aging.

Long-term influence of fixed lingual retainers on the development of gingival recession: A retrospective, longitudinal cohort study

OBJECTIVE

To investigate the long-term influence of fixed lingual retainers on the development of mandibular gingival recession and to compare the prevalence with untreated individuals.

MATERIALS AND METHODS

The material consisted of 144 subjects: 96 orthodontically treated patients followed for 5 years after therapy and 48 untreated age-matched subjects. The treated patients were divided in two groups: one receiving a fixed mandibular retainer (n = 48) and one receiving no form of retention in the mandible (n = 48). The presence or absence of gingival recession and calculus accumulation were scored before treatment (T0), after debonding (T1), and 5 years after debonding (T5) for each tooth in the mandibular intercanine region using plaster models and intraoral photographs. The chi-square test, one-way ANOVA, and Cochran's Q test were used to evaluate inter- and intragroup differences.

RESULTS

The prevalence of patients with recession increased gradually and significantly throughout the observation periods in all groups, but the intergroup differences at T5 were not significant. Significantly more calculus accumulation was observed at T5 in the retainer group compared with the group without retainers.

CONCLUSIONS

Long-term presence of fixed lingual retainers does not seem to increase the development of mandibular gingival recession, but does increase calculus accumulation.

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.

Correlation between parodontal indexes and orthodontic retainers: prospective study in a group of 16 patients

PURPOSE

Fixed retainers are used to stabilize dental elements after orthodontic treatment. Being it a permanent treatment, it is necessary to instruct patients about a constant and continuous monitoring of their periodontal conditions and a correct oral hygiene. The aim of this study was to highlight the possible adverse effects of bonded retainers on parameters correlated to the health conditions of periodontal tissues.

MATERIALS AND METHODS

We selected 16 patients, under treatment in the Orthodontics Department of University of Bari Dental School, who had undergone a lingual retainer insertion at the end of the orthodontic treatment. The patients were then divided into two groups (Control Group and Study Group) and monitored for 3 and 36 months, respectively. The following indexes were taken into consideration: gingival index (GI), plaque index (PI) and the presence of calculus (Calculus Index, CI), the probing depth and the presence of gingival recession on the six inferior frontal dental elements.

RESULTS

After the observation was carried out, any of the patients showed periodontal sockets and gingival recession. In the Study Group, only 1 patient had a PI score=3, the 7 left had scores between 0.66 and 2.83. In the Control Group, one patient had score=0, the other ones showed values between 0.5 and 1.66. The mean GI in the Study Group peaked at a score of 2.83, the minimum was 0.66; whereas in the Control Group the maximum value was 2 and the minimum 0.66. The CI in the Group Study was between 1 and 2. In the Control Group it was absent in only 1 patient, whereas in the remaining 7, it had a value between 0.3 and 1. The clinical data were studied by means of the Wilcoxon test. We found a statistically significant difference for what concerns the Plaque Indexes (PI) (P>0.05) and Calculus Indexes (CI) (P>0.1) in both groups, with higher scores in the Study Group, having retainers for 36 months. Any statistically significant difference was calculated for the GI.

CONCLUSIONS

We can therefore conclude that patients with lingual retainers need periodontal hygiene and treatment as to prevent, in the course of time, periodontal damages non-detectable in short-term.

Retention in orthodontics

Retention is necessary following orthodontic treatment to prevent relapse of the final occlusal outcome. Relapse can occur as a result of forces from the periodontal fibres around the teeth which tend to pull the teeth back towards their pre-treatment positions, and also from deflecting occlusal contacts if the final occlusion is less than ideal. Age changes, in the form of ongoing dentofacial growth, as well as changes in the surrounding soft tissues, can also affect the stability of the orthodontic outcome. It is therefore essential that orthodontists, patients and their general dental practitioners understand the importance of wearing retainers after orthodontic treatment. This article will update the reader on the different types of removable and fixed retainers, including their indications, duration of wear, and how they should be managed in order to minimise any unwanted effects on oral health and orthodontic outcomes. The key roles that the general dental practitioner can play in supporting their patients wearing orthodontic retainers are also emphasised.

Effects of different orthodontic retention protocols on the periodontal health of mandibular incisors

OBJECTIVES

To test the following two hypotheses: 1) different types of retainers result in distinct levels of biomarkers in gingival crevicular fluid (GCF) and 2) the retainer bonded to all mandibular anterior teeth induces more detrimental outcomes to the periodontium.

SETTING AND SAMPLE POPULATION

The Department of Orthodontics at the University of Florida. The population consisted of individuals in the retention phase of orthodontic treatment.

MATERIAL AND METHODS

This was a cross-sectional study that enrolled 36 individuals. Subjects in group 1 had retainers bonded to the mandibular canines only. Group 2 consisted of individuals having retainers bonded to all mandibular anterior teeth. Group 3 included patients using mandibular removable retainers. After clinical examination, GCF was collected from the mandibular incisor and biomarker levels were compared between the groups.

RESULTS

Plaque accumulation and gingivitis differed significantly among groups, with the highest median values in group 2 subjects. Pairwise comparison of the groups with respect to gingivitis showed significant differences between groups 1 and 2. Significant differences among groups were detected for RANKL, OPG, OPN, M-CSF, MMP-3, and MMP-9. The ratio RANKL/OPG was significantly higher in group 2 subjects, with pairwise comparisons indicating that groups 1 and 2 differed from group 3.

CONCLUSION

An association was found between orthodontic retention groups and GCF biomarker levels, which should be further explored in longitudinal studies. The presence of retainers bonded to all anterior teeth seems to increase plaque accumulation and gingivitis.

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.

Displacement and force distribution of splinted and tilted mandibular anterior teeth under occlusal loads: an in silico 3D finite element analysis

Background

Fixed orthodontic retainers have numerous advantages, but it is not known whether they can exert pathological forces on supporting tissues around the splinted teeth. The purpose of this study was to investigate how the inclination of the lower anterior teeth can affect dental displacement and also change the direction of occlusal loads exerted to dental and its supporting tissues.

Methods

Four three-dimensional finite element models of the anterior part of the mandible were designed. All the models contained the incisors and canines, their periodontal ligament layers (PDLs), the supporting bone (both spongy and cortical), and a pentaflex splinting wire placed in the lingual side of the teeth. Teeth inclination was considered to be 80° (model 1), 90° (model 2), 100° (model 3), and 110° (model 4) to the horizontal plane. The lower incisors were loaded with a 187-N vertical force. Their displacement patterns and the stress in their PDLs were evaluated.

Results

In incisors with 80° of inclination, less than a 0.1-mm lingual displacement was seen on the incisal edge and a similar distance of displacement towards the labial was seen on their root apices. However, in models with 90°–110° of inclination, the incisal edge displaced labially between about 0.01 and 0.45 mm, while root apices displaced lingually instead. By increasing the angle of the teeth, the strain in the periodontal ligament increased from about 37 to 58 mJ. The von Mises stresses around the cervical and apical areas differed for each tooth and each model, without a similar pattern. Increasing the angle of the teeth resulted in much higher cervical stresses in the incisors, but not in the canines. In the lateral incisor, cervical stress increased until 100° of inclination but reduced to about half by increasing the angle to 110°. Apical stress increased rather consistently in the incisor and lateral incisors, by increasing the inclination. However, in the canines, apical stress reduced to about half, from the first to fourth models.

Conclusions

Increasing the labial inclination can mostly harm the central incisors, followed by the lateral incisors. This finding warns against long durations of splinting in patients with higher and/or patients with reduced labial bone thickness.

Covering of fiber-reinforced composite bars by adhesive materials, is it necessary to improve the bond strength of lingual retainers?

Objectives:

The objectives were to evaluate the shear bond strength (SBS) of fiber-reinforced composite (FRC) retainers when bonding them to teeth with and without covering the FRC bars using two different adhesive systems.

Materials and Methods:

Hundred and twenty extracted human maxillary premolars were randomly divided into eight groups (n = 15). FRC bars (4 mm length, Everstick Ortho^®, Stick Tech, Oy, Turku, Finland) were bonded to the proximal (distal) surfaces of the teeth using two different adhesives (Tetric Flow [TF, Ivoclar Vivadent, Switzerland] and resin-modified glass ionomer cement [RMGIC, ODP, Vista, CA, USA]) with and without covering with the same adhesive. Specimens were exposed to thermocycling (625 cycles per day [5–55°C, intervals: 30 s] for 8 days). The SBS test was then performed using the universal testing machine (Zwick, GMBH, Ulm, Germany). After debonding, the remaining adhesive on the teeth was recorded by the adhesive remnant index (0–3).

Results:

The lowest mean SBS (standard deviation) was found in the TF group without covering with adhesive (12.6 [2.11] MPa), and the highest bond strength was in the TF group with covering with adhesive (16.01 [1.09] MPa). Overall, the uncovered RMGIC (15.65 [3.57] MPa) provided a higher SBS compared to the uncovered TF. Covering of FRC with TF led to a significant increase in SBS (P = 0.001), but this was not true for RMGIC (P = 0.807). Thermal cycling did not significantly change the SBS values (P = 0.537). Overall, eight groups were statistically different (ANOVA test, F = 3.32, P = 0.034), but no significant differences in bond failure locations were found between the groups (Fisher's exact tests, P = 0.92).

Conclusions:

The present findings showed no significant differences between SBS of FRC bars with and without covering by RMGIC. However, when using TF, there was a significant difference in SBS measurements between covering and noncovering groups. Therefore, the use of RMGIC without covering FRC bars can be suggested, which can be validated with in vivo studies.

Clinical and radiographic comparison of the effects of two types of fixed retainers on periodontium - a randomized clinical trial

Background

Most orthodontists believe that fixed retainers are necessary to maintain ideal dental relationships. However, untoward side effects might result from their long-term placement. The aim of this study was to evaluate the clinical and radiographic effect of two commonly used fixed retainers on the health of the periodontium.

Methods

Thirty patients were randomly divided into two groups to receive either a fiber-reinforced composite retainer or a spiral wire retainer extended on the lingual surfaces of both maxillary and mandibular arches from canine to canine. Periapical radiographs were obtained from the patients at the time of placement of the retainers and after the 6-month period to assess the radiographic conditions of the periodontium. Clinical examination was carried out at the same two time intervals.

Results

Even though there were no significant differences between the two groups of study at the beginning of the trial, there were statistically significant differences after the 6-month follow-up regarding the main outcomes of the study. Nearly all indices showed to deteriorate after 6 months in the fiber-reinforced group, while in the spiral wire group, this was not the case. As for the secondary outcomes, radiographic examination did not reveal any statistically significant differences after 6 months or between the two groups.

Conclusions

It can be concluded that spiral wire retainers elicit less detrimental periodontal response in the short-term follow-up compared to fiber-reinforced composite retainers as revealed by the primary outcomes of the study.

Trial registration

ClinicalTrials.gov: NCT01314729

Electronic supplementary material

The online version of this article (doi:10.1186/s40510-014-0047-8) contains supplementary material, which is available to authorized users.

Impact of orthodontic retainers on periodontal health status assessed by biomarkers in gingival crevicular fluid

OBJECTIVE

To evaluate whether biomarkers of inflammation and periodontal remodeling are differentially expressed in the gingival crevicular fluid (GCF) of patients wearing different types of orthodontic retainers.

MATERIALS AND METHODS

Thirty-one adult subjects (17 men and 14 women with an age range of 20 to 35 years) were allocated to three different groups. Group 1 consisted of 10 patients wearing fixed retainers, group 2 included 11 patients using lower removable retainers, and group 3 comprised 10 patients without retainers (control). Periodontal health assessment and GCF collection were carried out at two sites per subject: the lingual side of a central lower incisor and the lingual side of a lower second premolar. Aliquots from diluted GCF were screened for the presence of biomarkers using a microarray technique.

RESULTS

Group 1 patients exhibited a higher percentage of sites with visible plaque in the incisor region than the other groups (P = .03); no differences were noted in gingival bleeding and probing depths. The median concentrations (pg/mL) of interferon-gamma and interleukin-10 were significantly higher in the premolar sites of patients in group 2 (P = .01 and P = .04, respectively), whereas the concentration of matrix metalloproteinase-9 was significantly higher at the incisors of patients wearing fixed retainers (P = .02). A significant difference between the two sites was seen only in group 2.

CONCLUSIONS

The presence of different orthodontic retainers may promote specific alterations in the GCF composition. With retention periods potentially becoming longer, this finding may be of clinical significance.

Comparação de parâmetros periodontais após utilização de contenção ortodôntica com fio trançado e contenção modificada

OBJETIVO: o presente estudo teve como objetivo comparar dois tipos de contenções ortodônticas fixas, em relação a parâmetros periodontais estabelecidos. A contenção com fio trançado é a mais comumente utilizada e a contenção modificada apresenta dobras que têm a finalidade de permitir o livre acesso do fio dental às áreas interproximais. MÉTODOS: para esse estudo cruzado, foram selecionados 12 voluntários que utilizaram, por 6 meses, A) Contenção com fio trançado e B) Contenção modificada - sendo essas fixadas em todos os dentes do segmento anterior. Após esse período experimental, foram feitas as seguintes avaliações: Índice de Placa Dentária, Índice Gengival, Índice de Cálculo Dentário e Índice de Cálculo ao longo do fio de contenção. Os voluntários também responderam a um questionário com relação à utilização, conforto e higienização das contenções. RESULTADOS: foi observado que o índice de placa e o índice gengival foram maiores nas faces linguais (p<0,05) para a contenção modificada. Além disso, o índice de cálculo foi estatisticamente maior (p<0,05) considerando-se as faces linguais e proximais na utilização da contenção modificada. O índice de cálculo ao longo do fio também apresentou valores significativamente maiores (p<0,05) na contenção modificada. Em relação ao questionário, 58% dos voluntários consideraram que a contenção modificada é mais desconfortável; e 54% deles preferiram a contenção com fio trançado. CONCLUSÃO: a partir dos resultados obtidos, pode-se concluir que a contenção com fio trançado apresentou melhores resultados do que a contenção modificada, de acordo com os parâmetros periodontais avaliados, além de apresentar maior conforto e preferência na sua utilização.

Removable thermoplastic appliances as orthodontic retainers--a prospective study of different wear regimens

The aim of this prospective study was to evaluate and compare stability after 6 months of Essix retainer use. Patients' perceptions of wearing the retainer were also evaluated. A total of 69 patients, 53 girls and 16 boys [mean age 15.7 years, standard deviation (SD) 1.96], were included in the study and randomized into two groups with different wear regimens; full-time wear for 3 months and thereafter at night (group A) compared to full-time wear for 1 week and thereafter at night only (group B). Sixty patients completed the study and thus, group A comprised 30 maxillary retainers and 18 mandibular retainers and group B 30 maxillary and 18 mandibular retainers. Little's irregularity index (LII), overjet, and overbite were measured at debond (T(1)) and after 6 months (T(2)). Differences within and between groups were analysed with a Mann-Whitney test. At T(2), all patients completed a questionnaire in order to evaluate their experience of wearing an Essix retainer and how they complied with the given instructions. Differences in LII during T(1)-T(2) were 0.44 and 0.49 mm for group A and B, respectively, but with no significant difference between the groups. There were also no significant changes in overjet and overbite within or between the groups during T(1)-T(2). According to the responses to the questionnaire, the retainer was well tolerated by the patients. It was therefore concluded that the Essix retainer is sufficient for maintaining the results after orthodontic treatment and that night-time wear is adequate.

Glass fibre reinforced versus multistranded bonded orthodontic retainers: a 2 year prospective multi-centre study

The objective of this study was to compare glass fibre reinforced (GFR) with multistranded bonded orthodontic retainers in terms of success rate and periodontal implications. A 2 year parallel study was conducted of 184 patients scheduled to receive bonded retainers in the upper and lower anterior segments. In three centres, the patients (mean age 14 years; 90 males and 94 females) were sequentially assigned to receive GFR retainers containing 500 unidirectional glass fibres (GFR500), 1000 unidirectional glass fibres (GFR1000), or multistranded retainers (gold standard). Retainer failures and periodontal conditions were monitored every 6 months. In a control group of 90 subjects without retainers, periodontal conditions were examined (negative control). Of the 274 recruited patients, 15 dropped out during the 2 year study period. Kaplan-Meier plots were drawn to assess survival of the different retainers. The Mantel-Cox log-rank test was used to identify significant differences in survival functions among the groups. Repeated measures analysis of variance and appropriate post hoc tests were adopted to evaluate periodontal conditions over time. GFR retainers showed unacceptably high failure rates in comparison with multistranded retainers (51 versus 12 per cent). The most significant periodontal conditions were found in patients with GFR retainers with no significant differences between the GFR500 and the GFR1000 group for any parameter at any time point. Subjects without retainers showed significantly lower levels of gingival inflammation and plaque accumulation when compared with patients in any retainer group. Multistranded retainers should remain the gold standard for orthodontic retention, although periodontal complications are common. The use of GFR retainers should be discouraged in daily practice.

Orthodontic retention patterns in the United Kingdom

OBJECTIVE

To determine whether retention patterns in the UK are influenced by operator gender, age or sphere of practice.

DESIGN

Postal self-completed questionnaire.

SETTINGS

Private practice, NHS practice, hospital practice and community practice.

SUBJECTS

Two hundred and forty orthodontists out of 301 returned their questionnaires (80% response).

METHOD

Respondents were asked to report on their retention regimes for a hypothetical crowded class II division I case in the one or more practice settings they worked in.

RESULTS

Most respondents (61%) worked in more than one practice setting. Vacuum retainers were the most commonly used type in NHS practice and hospital practice while Hawley retainers were frequently used in community practice. Vacuum retainers were also most popular in private practice though often used in conjunction with bonded retainers in both arches, particularly the mandible. Regression analysis revealed that there were no statistically significant associations between retainer preference and gender or age. However, trends were identified that suggested females were less likely to use bonded retainers in the maxilla than males, and older clinicians were more likely to use bonded retainers in the mandible than younger colleagues. Practice setting differences were found to be statistically significant (P< or =0.004) with bonded retainers being more frequently used in private practice.

CONCLUSIONS

Vacuum retainers are popular in NHS, hospital and private practice. Bonded retainers are more commonly used in private practice than in other settings.

A survey on orthodontic retention procedures in The Netherlands

The objective of this study was to survey retention procedures used in orthodontic practices in The Netherlands. A questionnaire was sent to all 279 orthodontists working in The Netherlands. The questionnaire consisted of six parts, mainly containing multiple-choice questions. Information as to background data on the individual orthodontist, retention in general, frequency of different types of removable or bonded retainers that were used, retention protocol, and the type and size of the wire used for bonded retainers was assessed. All statistical analyses were performed using Statistical Package for Social Sciences version 12.0.1. Tests for the relationship between two items were based on the chi-square test. The overall response rate was 91 per cent. Most orthodontists placed a bonded retainer in the upper and lower arch, except when the upper arch was expanded during treatment or when extractions were performed in the upper arch, in which case they placed a removable retainer. Opinions varied with regard to how many hours the removable retainers should be worn and the duration of the retention phase. Contraindications for bonded retainers were given by 96 per cent of the orthodontists, with poor oral hygiene being the most commonly mentioned. As far as bonded retainers were concerned, 84 per cent of the orthodontists preferred permanent retention. Fifty-nine per cent of the orthodontists believed that a practice guideline for retention after orthodontic treatment needs to be developed, which was confirmed by the varied responses in this survey.

Bond failure rates for V-loop vs straight wire lingual retainers

INTRODUCTION

The V-loop bonded lingual retainer is an innovative design that allows the patient to floss with ease, a significant advantage over the conventional straight wire design for interproximal plaque control. The aim of this retrospective study was to compare the efficacy of straight wire and V-loop fixed retainers with respect to detachment rate when used to stabilize maxillary or mandibular anterior teeth after orthodontic treatment.

METHODS

Fixed, customized retainers were placed in 300 patients and followed for 6 months. The conventional retainer system was a .0175-in stainless steel multi-stranded wire placed as a straight, bonded lingual retainer. The newer system was a .016-in stainless steel black Australian wire placed in a V-loop design.

RESULTS

The detachment rates were 14.3% for the V-loop design and 12.4% for the straight wire retainer. The difference was not statistically significant.

CONCLUSIONS

The V-loop retainer system addresses cleanability and physiologic adaptability, both critical for the clinical success of bonded lingual retainers used for long-term retention. The interdental wire span of the V-loop design allows easier access for flossing and sufficient flexibility for independent tooth movement in the periodontal space. Patient acceptance of the V-loop bonded lingual retainer was excellent, and most patients in this study found the retainer comfortable and easy to floss.

The association of orthodontic treatment and fixed retainers with gingival health

BACKGROUND

The use of postorthodontic fixed retainers made of wire and composite resin bonded to the lingual/palatal tooth aspect is a common practice that can affect gingival health. The purpose of this study was to evaluate the association of orthodontic treatment and fixed retainers with gingival health.

METHODS

The study included 92 consecutive subjects who arrived for routine dental examination at a military dental clinic between May and August 2007. Plaque and gingival indices, gingival recession, probing depth, and bleeding on probing were measured at the anterior sextants. When a fixed retainer was present, the distance was measured between the retainer and incisal edge and to the cemento-enamel junction. Past orthodontic treatment and smoking habits were self-reported. Postorthodontic patients were sorted by the presence or absence of fixed retainers.

RESULTS

The mean probing depth was 1.90 +/- 0.2 mm, and gingival recession was 0.06 +/- 0.02 mm; 20.8% of all sites exhibited bleeding on probing. Current smoking was reported by 20 (21.7%) patients. Labial gingival recession was significantly greater in treated (0.13 +/- 0.2 mm) patients compared to non-treated patients (0.05 +/- 0.2 mm; P = 0.03). Localized lingual gingival recession was significantly greater in teeth with fixed retainers (0.09 +/- 0.2 mm) compared to teeth with no fixed retainers (0.01 +/- 0.1 mm; P = 0.0002), as were plaque and gingival indices and bleeding on probing. Plaque on the lingual/palatal aspect showed a weak, positive correlation with lingual gingival recession (r = 0.16; P = 0.033).

CONCLUSION

Orthodontic treatment and fixed retainers were associated with an increased incidence of gingival recession, increased plaque retention, and increased bleeding on probing; however, the magnitude of the difference in recession was of low clinical significance.

Long-term periodontal status of patients with mandibular lingual fixed retention

The purpose of this study was to evaluate the periodontal tissues of patients with mandibular fixed retention for long or short periods of time. A total of 64 individuals were selected for this study using the following inclusion criteria: long-term lingual fixed retention; identical type of lingual fixed retainer bonded with the same materials; no cavities, restorations, or fractures of the mandibular anterior teeth; absence of habits and occlusal interferences; and canine guidance bilaterally. The resultant sample comprised 32 patients (mean age 25 years) who had been in retention for a mean period of 9.65 years (range 9-11 years) and an equal number retained for a period between 3 and 6 months. Plaque, gingival, and calculus indices, probing pocket depth, marginal recession, and bone level at the mandibular six anterior teeth were recorded for both groups. Demographic, clinical, and radiographic data were investigated with conventional descriptive statistics. Comparisons of the different variables between the two participant groups (long- and short-term retention) were carried out using a Mann-Whitney test for indices (plaque, gingival, and calculus), and a Fisher's exact test (two sided) for the remaining variables. No significant difference was found with respect to the plaque and gingival indices and bone level between the two groups. The long-term group presented higher calculus accumulation, greater marginal recession, and increased probing depth (P < 0.05). The results of this study raise the question of the appropriateness of lingual fixed retainers as a standard retention plan for all patients regardless of their attitude to dental hygiene. They also emphasize the importance of individual variability and cautious application of retention protocols after a thorough consideration of issues related to the anatomy of tissues and oral hygiene.