Inadvertent side effects of fixed lingual retainers : An in vitro study

PURPOSE

To better understand the side effects of fixed lingual retainers by means of an in vitro study in a two-tooth model determining the three-dimensional (3D) force-moment components acting at adjacent teeth combined with different composite-wire interfaces.

METHODS

Triple-stranded round retainer wires were embedded in cured disks of flowable composite. At one side the composite-wire interface was untreated and checked to be absolutely fix. At the other side the composite-wire interface was configured as either an isolated compound with (1) petroleum jelly coating, or an adhered compound with (2) no manipulation, (3) ethanol degreasing or (4) ethanol degreasing and rectangular bending of the wire ends. The 3D force-moment components were registered, while the intertooth distance was increased in steps of 0.01 mm leading to increasing tension of the wire. Measurements were repeated after artificially aging the specimens.

RESULTS

Retainer wire specimens with adhered compound (2, 3, 4) showed negative vestibulo-oral moments ranging maximally each between -0.3 and -0.9 Nmm in opposite direction to positive moments of 1.9 Nmm for specimens with isolated compound 1. Significant tipping moments occurred in the group with isolated compound at lower forces than in those groups with adhered compound. Similar effects were observed after artificial aging.

CONCLUSION

Side effects emerge under specific circumstances: an altered adhesive compound combined with the presence of oral forces. Compounds with lost adhesion at the composite-wire interface showed rotational moments in the direction of the wire windings even during low tensile forces similar to those that may occur in clinical settings. Opposite rotational moments leading to unwinding of the wire may occur in cases with adhered compounds at higher tensile forces. Utilization of round triple-stranded retainer wires without bent ends are of higher risk to induce inadvertent side effects.

Three-dimensional microanalysis of tooth movement during the first 6 months of orthodontic double retention

INTRODUCTION

This study performed a 3-dimensional analysis of tooth movement during orthodontic retention to assess the effectiveness of double retention (fixed and removable) in preventing undesired tooth movement.

METHODS

One hundred randomly selected patients were included at the initiation of double orthodontic retention with fixed retainers and vacuum-formed splints (recommended to be worn 22 h/d) in both arches. Intraoral scans were performed directly (T0), 1 month (n = 88), 3 months (T2) (n = 78), and 6 months (T3) (n = 66) after retainer bonding. Nine reference points were marked on each tooth in every patient. Subsequent scans were superimposed, and point displacement was calculated. Statistical analysis was performed using the R statistical software (version 4.2.2; R Core Team, Vienna, Austria).

RESULTS

Sample size calculation determined at least 55 patients were needed. The total dropout between T0 and T3 was 34 patients (did not show up for appointment). The median absolute displacement value of a single point between T0 and T3 was 0.015 mm. The most stable teeth were mandibular central incisors, whereas the least stable were mandibular molars. Most tooth displacements occurred between T0 and T2, then slowed down significantly.

CONCLUSIONS

Double orthodontic retention prevents major tooth displacements in most patients during the first 6 months of retention; however, larger, unpredictable single-tooth displacement may occur in individual patients.

Patients' perception of orthodontic retainers: a systematic review

BACKGROUND

Orthodontic retainers are widely used to prevent relapses after orthodontic treatment; however, evidence about patients' perceptions of retainers is lacking.

OBJECTIVE

To assess patients' perception of orthodontic retainers.

SEARCH METHODS

PubMed, Web of Science, Scopus, LILACS, LIVIVO, Cochrane Library, and gray literature (Google Scholar) were searched without date or language restrictions. A manual search of the reference lists of the included articles was also performed.

SELECTION CRITERIA

Studies comparing patients' perceptions of wearing orthodontic retainers were included.

DATA COLLECTION AND ANALYSIS

According to the study design, the risk of bias (RoB) assessment was performed using RoB 2.0 or ROBINS-I. The level of evidence was assessed through the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) tool.

RESULTS

Seventeen studies met the eligibility criteria. After the RoB assessment, 12 randomized controlled trials presented a high RoB, and 4 non-randomized controlled trials presented a moderate RoB. The certainty of evidence was classified as very low for the four assessed outcomes. The studies generally reported an initial temporary negative impact of orthodontic retainers. Different esthetic, functional, and ease-of-use advantages are reported using removable and fixed retainers. A quantitative analysis was not performed due to the considerable clinical and methodological heterogeneity among the studies.

CONCLUSION

The current evidence, although very limited, suggests that orthodontic retainers have an initial negative impact related to discomfort and functional limitations, but they seem to regress over time. There is a preference for thermoplastic over Hawley-type retainers. However, thermoplastic retainers cause different functional difficulties, and bonded retainers present the advantage of affecting speech function less than orthodontic removable retainers, although they can facilitate oral hygiene problems.

REGISTRATION

PROSPERO (CRD42022306665).

Failure frequency of fixed mandibular retainers after pre-treatment of the enamel surface with pumice versus sandblasting-a randomized controlled trial

BACKGROUND/OBJECTIVES

To compare retainer survival, periodontal health, and caries implications of fixed lower retainers bonded after pre-treatment of the enamel surface with either pumice or sandblasting.

TRIAL DESIGN

Two-arm parallel-group, two-center randomized controlled clinical trial.

METHODS

One hundred sixty patients (101 females, 59 males, mean age: 17.9) requiring mandibular retainers were consecutively recruited. Patients were randomly allocated to have pre-treatment of the enamel surface with either pumice (n = 80) or sandblasting (n = 80). The primary outcome was retainer survival at 3 (T1) and 12 months (T2) control. Secondary outcomes were carious lesions and periodontal health: plaque index (PI), gingival index (GI), calculus index (CI), and probing depth (PD). The randomization sequence was generated using an online randomization and allocation concealment was secured by contacting the sequence generator for treatment assignment. Blinding was not possible at T0 due to the nature of the intervention. Statistical analyses were carried out using the t-test, Fisher's exact test, repeated measure analysis of variance, and log rank test.

RESULTS

Overall, the risk of bonding failure at T1 was 6.7 per cent and at T2 6.9 per cent. There were no statistically significant differences in failure rate between the two groups, neither at T1 (P = 1.000) nor at T2 (P = 0.360). No statistically significant differences were found for the intercanine periodontal indices GI, PI, CI, PD, and caries between the two groups at T0 and T1. At T2, significantly more gingivitis and plaque were seen in the sandblasting group (P = 0.05 and P = 0.047, respectively) compared with the pumice group. Calculus increased during the follow-up period in both groups (P ≤ 0.001) as well as plaque levels (P ≤ 0.001 and P = 0.025, respectively). No harm was reported.

CONCLUSIONS

Enamel sandblasting prior to bonding mandibular retainers is not better at preventing bonding failure.

REGISTRATION

275767 (https://www.researchweb.org/is/sverige).

The dark side of fixed retainers: Case series

This article focuses on on the presentation and management 9 adult patients who experienced complications because of their maxillary or mandibular fixed retainers 5-33 years after orthodontic treatment. Such complications include the development of an anterior crossbite, open bite, incisal cant, and twist- and x-effects. The detrimental effects on periodontal health were highlighted, especially in the mandibular canines. A range of fixed retainer types was identified, including flexible spiral wire bonded to 4 maxillary or 6 mandibular anterior teeth, rigid wire bonded to mandibular canines only and fiber-reinforced composite fixed retainer. Orthodontic retreatment was necessary in all patients using fixed appliances or clear aligners. Radiographic findings from cone-beam computed tomography or orthopantomogram before and after retreatment are presented when available. Despite the improvement of teeth position clinically, the cone-beam computed tomography scans taken directly after the completion of orthodontic retreatment did not show notable improvement with regards to root proximity to the cortical plates. The prevention of further complications was highlighted, including the use of dual retention, remote monitoring, frequent follow-up appointments and the importance of developing clear guidelines for monitoring patients in retention for treating clinicians and general dentists to promote early detection of adverse changes.

[Evaluation of the effect of 3D printing resin splint based on the retention effect of orthodontic treatment in patients with periodontal disease]

PURPOSE

To investigate the difference in the retention effect of 3D printing resin splint and Hawley retainer combined with lingual retention wire in periodontal disease patients after orthodontic treatment.

METHODS

Forty patients who finished orthodontic treatment for periodontal disease from January 2021 to February 2022 were selected and divided into experimental group and control group according to the random number table method, with 20 patients in each group. Patients in the experimental group used 3D printing resin splint for retention, while patients in the control group used Hawley retainer combined with a lingual retention wire for retention. The chair-side operation time of the retainers was recorded for both groups. The maxillary and mandibular cuspid width, molar width, overjet, overbite and irregularity index were measured at 1 month and 6 months after orthodontic treatment in both groups. Statistical analysis was performed with SPSS 12.0 software package.

RESULTS

The mean time for chair-side manipulation of experimental group and control group was 8.23, 11.17 min, respectively. The difference between the two groups was statistically significant (P＜0.05) when comparing the width of the maxillary and mandibular cusps, the width of the molars, overjet, overbite and the irregularity index after 1 month and 6 months of wear of the retainers, which were significantly greater in the experimental group than in the control group at 6 months(P＜0.05).

CONCLUSIONS

3D printing resin splint, with short chair-side manipulation time, was more effective than Hawley retainer combined with a lingual retention wire, and the efficacy of both groups was otherwise generally consistent.

Effects of fixed retainers on gingival recession - a 10-year retrospective study

OBJECTIVE

The aetiology of gingival recessions is not fully understood, and no evidence has yet emerged of a single predisposing factor that instigates this apical shift of the gingival margin. Nonetheless, both fixed retainers and orthodontic treatment have been cited as potential risk factors. The aim of this study was to assess the effects of orthodontic treatment and orthodontic fixed retainers on gingival recessions.

SUBJECTS AND METHODS

In total, 105 patients at the Department of Orthodontics at the University of Gothenburg who had undergone orthodontic treatment between 1995 - 2003 were included in this study. Intraoral photographs of the anterior segment and study casts acquired at baseline (pre-treatment), post-treatment and at the 10-year follow-up were used as recorded measurements of gingival recession and orthodontic treatment. At the 10-year follow-up, the patients were divided into two groups based on: long-term (10 years) presence of a fixed retainer [orthodontic treatment and retainer (OR) group; N = 76]; and short-term (<5 years) presence of a fixed retainer [orthodontic treatment (O) group; N = 57]. These groups were compared to a control group (C) of untreated subjects (N = 29).

RESULTS

In the anterior segment, gingival recessions were not present at baseline and post-treatment between the two orthodontically treated groups. At the 10-year follow-up, there was no statistically significant difference between the two orthodontically treated groups and the controls.

CONCLUSIONS

Orthodontic treatment per se does not increase the risk for gingival recessions, nor does the use of fixed retainers following orthodontic treatment.

[Canine avulsion: An extreme complication of a fixed mandibular lingual retainer]

INTRODUCTION

The use of fixed retainers at the end of a course of orthodontic treatment has become standard practice. The main complication that can occur with fixed retainers is the detachment of the wire from one or more teeth. A less common complication is unwanted tooth movement.

METHOD

This article presents a patient with extreme tooth movement associated with a mandibular fixed retainer. Ten years after orthodontic treatment, a 26-year-old male sought treatment for post-orthodontic movement of the mandibular anterior six teeth. Despite the fixed retainer still being attached to all teeth, the apex of the right canine was completed avulsed labially. Severe labial recession was also present on the left lateral incisor. The canine was extracted, and the fixed retainer was removed. Significant root resorption identified on a panoramic radiograph contraindicated any further extensive orthodontic intervention.

DISCUSSION

This case highlights that clinicians and patients should be aware of this rare but serious complication.

Patient-Reported Outcome Measures on Oral Hygiene, Periodontal Health, and Treatment Satisfaction of Orthodontic Retention Patients up to Ten Years after Treatment-A Cross-Sectional Study

Background: This cross-sectional study evaluated patient-reported outcome measures (PROMs) on (1) oral hygiene, (2) periodontal health, (3) retainer failure, (4) orthodontic treatment satisfaction, and (5) outcome satisfaction in orthodontic retention patients. The purpose of the study was to evaluate whether orthodontic retention treatment is associated with patient-reported outcome measures on oral hygiene, periodontal health, and treatment satisfaction. Methods: A ten-item questionnaire on the five PROMs was conducted among 211 consecutive retention patients up to ten years following orthodontic treatment. Linear regression models were computed to detect possible associations between the PROMs and retention treatment or patient characteristics. Results: The presence of a fixed lingual retainer was not associated with the reduced ability to perform oral hygiene, self-perceived periodontal health, or orthodontic outcome satisfaction. Older patients were more content with the orthodontic treatment result (p < 0.05). Patients with fixed lingual retainers in the mandible were less satisfied with the course of orthodontic treatment (p < 0.05). Smokers more often reported gingival bleeding (p < 0.05). Females reported increased gingival recessions (p < 0.05) and perceived their teeth as longer than before treatment (p < 0.05). Longer orthodontic treatment duration corresponded to retainer failure (p < 0.05). Conclusions: In general, long-term orthodontic retention patients were satisfied with orthodontic treatment. These patients reported the satisfactory ability to perform adequate oral hygiene and periodontal health, and they communicated a high degree of treatment and outcome contentment. However, patients with a retainer in the mandible were less satisfied with orthodontic treatment.

The Impact of Orthodontic Retainers on Gingival Recession: A Best-Evidence Review

Retention is a critical phase of orthodontic therapy and aims to maintain occlusal stability and avoid crowding relapse. This best-evidence article reviews the effects of the different types of orthodontic retention appliances, fixed and removable, on the development and progression of gingival recession at the mandibular anterior teeth. Searched databases included PubMed, Scopus, Cochrane Library, Embase, and Dentistry and Oral Sciences. Eleven qualifying publications, including retrospective, prospective, and cross-sectional studies, were included in this review. These studies either did not demonstrate an association between orthodontic retainers and gingival recession or reported that the resulting recession defects were minimal when an association was shown. An important consideration is that recession could be a late finding following the placement of a retainer and, therefore, may be incipient or absent in short-term evaluations. Prospective studies that specifically address the role that properly positioned fixed retainers may have on gingival recession are needed before a definitive conclusion can be generalized with regard to recommended retention protocols. Factors such as duration of retainer use, number of bonded teeth, and position of fixed retainers relative to their proximity to gingival tissues are not fully elucidated but may have influencing roles on gingival recession. The use of retainers should be based on orthodontic indications to maintain a stable dental arch form, esthetics, and occlusion. Effective oral hygiene and follow-up regimens remain the gold standard in maintaining periodontal health and preventing gingival recession.

[The quality of life of patients after orthodontic treatment depending on the use of different types of retention appliances]

AIM

To assess the impact of the type of retention device on the quality of life of orthodontic patients.

MATERIAL AND METHODS

311 patients were divided into four groups according to age. At the end of active orthodontic treatment, retainers were installed. After 6 months, a questionnaire was conducted using the standard OHIP-14 questionnaire in order to identify the attitude to the equipment used, the presence or absence of relapses and satisfaction with the state of the dental system.

RESULTS

The number of relapses in all groups is approximately at the same level, which indicates almost equal opportunities for retainers to retain the achieved result. There is no correlation between the convenience of using a particular type of retainer and the willingness to do so.

CONCLUSION

The motivation of patients to use removable or non-removable retention devices to a certain extent depends not only on the type of retainer, but also on the age at which the treatment was performed.

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.

In Vitro Assessment of Cytotoxicity and Estrogenicity of Vivera® Retainers

AIM

To investigate the cytotoxicity and estrogenicity of Vivera® retainers by assessing their biological behavioral effects as-received from the manufacturer and after retrieved from patients.

MATERIALS AND METHODS

In this, in vitro investigation six sets (maxillary and mandibular) of Vivera® retainers, three as received and three retrieved after four weeks of use by patients of an orthodontic postgraduate clinic, were immersed in the normal saline solution for 14 days following different modes of sterilization. The estrogenicity assays involved two cell lines, namely the estrogen-sensitive MCF-7 and the estrogen-insensitive MDA-MB-231. Following a 6 day incubation with the solutions to be tested, at concentrations varying from 5% to 20% v/v in medium supplemented with 2% fetal calf serum devoid of endogenous estrogens, estrogenicity was assessed by cell counting; p-Estradiol was used as positive control. The statistical analysis of data was performed with two-way analysis of variance (ANOVA) with appliance and concentration as predictors. Differences were further investigated with the Tukey multiple comparison tests at the 0.05 level of significance.

RESULTS

No significant MCF-7 proliferation was induced by the three samples compared either to the eluents from as-received retainers or to the negative control. As expected, p-estradiol induced a potent stimulation of MCF-7 cell proliferation, while no effect was observed on MDA-MB-231 cells.

CONCLUSION

Under the conditions of this experiment eluents of as-received and retrieved Vivera® retainers did not seem to exhibit xenoestrogenic activity.

CLINICAL SIGNIFICANCE

Vivera® retainers can be used as part-time removable oral appliances following the manufacturer's instructions.

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.

Orthodontic treatment for prominent upper front teeth (Class II malocclusion) in children and adolescents

BACKGROUND

Prominent upper front teeth are a common problem affecting about a quarter of 12-year-old children in the UK. The condition develops when permanent teeth erupt. These teeth are more likely to be injured and their appearance can cause significant distress. Children are often referred to an orthodontist for treatment with dental braces to reduce the prominence of their teeth. If a child is referred at a young age, the orthodontist is faced with the dilemma of whether to treat the patient early or to wait and provide treatment in adolescence.

OBJECTIVES

To assess the effects of orthodontic treatment for prominent upper front teeth initiated when children are seven to 11 years old ('early treatment' in two phases) compared to in adolescence at around 12 to 16 years old ('late treatment' in one phase); to assess the effects of late treatment compared to no treatment; and to assess the effects of different types of orthodontic braces.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 27 September 2017), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2017, Issue 8), MEDLINE Ovid (1946 to 27 September 2017), and Embase Ovid (1980 to 27 September 2017). The US National Institutes of Health Ongoing Trials Registry (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

Randomised controlled trials of orthodontic treatments to correct prominent upper front teeth (Class II malocclusion) in children and adolescents. We included trials that compared early treatment in children (two-phase) with any type of orthodontic braces (removable, fixed, functional) or head-braces versus late treatment in adolescents (one-phase) with any type of orthodontic braces or head-braces, and trials that compared any type of orthodontic braces or head-braces versus no treatment or another type of orthodontic brace or appliance (where treatment started at a similar age in the intervention groups).We excluded trials involving participants with a cleft lip or palate, or other craniofacial deformity/syndrome, and trials that recruited patients who had previously received surgical treatment for their Class II malocclusion.

DATA COLLECTION AND ANALYSIS

Review authors screened the search results, extracted data and assessed risk of bias independently. We used odds ratios (ORs) and 95% confidence intervals (CIs) for dichotomous outcomes, and mean differences (MDs) and 95% CIs for continuous outcomes. We used the fixed-effect model for meta-analyses including two or three studies and the random-effects model for more than three studies.

MAIN RESULTS

We included 27 RCTs based on data from 1251 participants.Three trials compared early treatment with a functional appliance versus late treatment for overjet, ANB and incisal trauma. After phase one of early treatment (i.e. before the other group had received any intervention), there was a reduction in overjet and ANB reduction favouring treatment with a functional appliance; however, when both groups had completed treatment, there was no difference between groups in final overjet (MD 0.21, 95% CI -0.10 to 0.51, P = 0.18; 343 participants) (low-quality evidence) or ANB (MD -0.02, 95% CI -0.47 to 0.43; 347 participants) (moderate-quality evidence). Early treatment with functional appliances reduced the incidence of incisal trauma compared to late treatment (OR 0.56, 95% CI 0.33 to 0.95; 332 participants) (moderate-quality evidence). The difference in the incidence of incisal trauma was clinically important with 30% (51/171) of participants reporting new trauma in the late treatment group compared to only 19% (31/161) of participants who had received early treatment.Two trials compared early treatment using headgear versus late treatment. After phase one of early treatment, headgear had reduced overjet and ANB; however, when both groups had completed treatment, there was no evidence of a difference between groups in overjet (MD -0.22, 95% CI -0.56 to 0.12; 238 participants) (low-quality evidence) or ANB (MD -0.27, 95% CI -0.80 to 0.26; 231 participants) (low-quality evidence). Early (two-phase) treatment with headgear reduced the incidence of incisal trauma (OR 0.45, 95% CI 0.25 to 0.80; 237 participants) (low-quality evidence), with almost half the incidence of new incisal trauma (24/117) compared to the late treatment group (44/120).Seven trials compared late treatment with functional appliances versus no treatment. There was a reduction in final overjet with both fixed functional appliances (MD -5.46 mm, 95% CI -6.63 to -4.28; 2 trials, 61 participants) and removable functional appliances (MD -4.62, 95% CI -5.33 to -3.92; 3 trials, 122 participants) (low-quality evidence). There was no evidence of a difference in final ANB between fixed functional appliances and no treatment (MD -0.53°, 95% CI -1.27 to -0.22; 3 trials, 89 participants) (low-quality evidence), but removable functional appliances seemed to reduce ANB compared to no treatment (MD -2.37°, 95% CI -3.01 to -1.74; 2 trials, 99 participants) (low-quality evidence).Six trials compared orthodontic treatment for adolescents with Twin Block versus other appliances and found no difference in overjet (0.08 mm, 95% CI -0.60 to 0.76; 4 trials, 259 participants) (low-quality evidence). The reduction in ANB favoured treatment with a Twin Block (-0.56°, 95% CI -0.96 to -0.16; 6 trials, 320 participants) (low-quality evidence).Three trials compared orthodontic treatment for adolescents with removable functional appliances versus fixed functional appliances and found a reduction in overjet in favour of fixed appliances (0.74, 95% CI 0.15 to 1.33; two trials, 154 participants) (low-quality evidence), and a reduction in ANB in favour of removable appliances (-1.04°, 95% CI -1.60 to -0.49; 3 trials, 185 participants) (low-quality evidence).

AUTHORS' CONCLUSIONS

Evidence of low to moderate quality suggests that providing early orthodontic treatment for children with prominent upper front teeth is more effective for reducing the incidence of incisal trauma than providing one course of orthodontic treatment in adolescence. There appear to be no other advantages of providing early treatment when compared to late treatment. Low-quality evidence suggests that, compared to no treatment, late treatment in adolescence with functional appliances, is effective for reducing the prominence of upper front teeth.

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.

[Orthodontic fixed retainer: fix or not fix? that is the question]

Orthodontic fixed retainer is widely used, as an orthodontic retention appliance, for nearly four decades. It answers the need for prolonged retention with minimum patient compliance. The effectiveness of fixed retainers was compared to other retention devices in several studies, and was found as effective as removable appliances. But, further high quality research is still needed. A bonded fixed retainer was suspected as an obstacle that impedes the patient's ability to keep satisfactory oral hygiene. But research failed to prove the influence of fixed retainers on periodontal health or white spot lesion occurrence as clinically significant. The definite downsides of fixed retainer are the risk of retainer breakage, and unwanted tooth movements. A typical tooth movement can appear even without a retainer breakage, including a change of torque of a mandibular incisor or skewing of the anterior mandibular arch segment. Both the dentist and the orthodontist are encouraged to be familiarized with these possible side effects, recognized them as soon as possible, and consider changing the retention protocol, when appropriate.

Upper bonded retainers

OBJECTIVE

To assess the frequency and type of upper bonded retainer failure and to identify possible predisposing factors.

MATERIALS AND METHODS

The records of 466 consecutive patients with upper bonded retainers were analyzed retrospectively with respect to retainer failures and failure type as well as timing of failure, differences among operators, and the number of defects of the multibracket appliances (MB) prior to the retention period.

RESULTS

A total of 58.2% of all patients experienced retainer failures. The average failure odds were 1.26 failures per retainer. The odds were highest for 3-3 retainers (1.37) and lowest for the 1-1 retainer (0.54). The detachment and total loss rates were significantly influenced by operator experience-both rates were lower for experienced practitioners. Total retainer losses occurred more frequently in case of previous MB defects, while retainer fractures were seen more frequently when the retainer included the canines.

CONCLUSIONS

Upper bonded retainer failures are a frequent problem during the retention period (58.2% of patients). Less operator experience correlated with higher failure rates. An increased number of total retainer losses must also be expected with a decreasing number of bonding sites and in cases involving previous MB defects.

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.

Emergency orthodontic care

Orthodontic appliances or parts of orthodontic appliances have caused problems from less severe like discomfort, ulcers and irritation of lips or cheeks to most severe problems like swallowing or aspiration of appliances or its parts. The type of appliances that have caused problems and their clinical management are discussed. Suggestions are made to try and avoid the problems that were encountered in the literature in patients undergoing orthodontic treatment.

Gingival health and relapse tendency: a prospective study of two types of lower fixed retainers

BACKGROUND

Different types and diameters of wire are used in bonded lingual retainers. Some clinicians bond a small diameter multistrand wire to each tooth, while other clinicians bond a large diameter wire to the lingual surfaces of the lower canines.

AIM

To compare the gingival health, plaque accumulation, tooth stability and integrity of multistrand wire and round wire bonded lingual retainers.

METHODS

Sixty-two subjects, who had completed treatment and who required fixed retention for the lower anterior segment, were assigned to either the Round wire retainer group or the Multistrand wire retainer group. In the Round wire retainer group, a 0.036 inch round, stainless steel wire was bonded to the lingual surfaces of both lower canines. The Multistrand retainer group had a 0.015 inch multistrand wire bonded to the lingual surfaces of all lower anterior teeth. At least 12 months after debonding, the subjects were recalled and the following variables were recorded: Oral Hygiene Index (OHI), Plaque Index (PI) of the lower anterior teeth, Gingival Index (GI) of the lower anterior teeth, Irregularity Index (IRI) of the lower anterior teeth, and the number of broken retainers.

RESULTS

There were no significant differences between the PI (p = 0.165) and GI (p = 0.150) of the two groups. More plaque was found on the distal surfaces of the lower anterior teeth in the group with multistrand wire retainers (p = 0.02). The lower anterior teeth were significantly more irregular in the group with round wire retainers compared to the group with multistrand wire retainers (p = 0.002). Although the multistrand wire retainers fractured more frequently than the round wire retainers the difference was not statistically significant (p = 0.325).

CONCLUSION

More plaque accumulated on the distal surfaces of the lower anterior teeth in subjects with multistrand wire retainers than in subjects with round wire retainers. Multistrand wire retainers were better at maintaining incisor alignment than single span, round wire retainers.

Subjective evaluation of orthodontic treatment and potential side effects of bonded lingual retainers

The primary aim of this study was to evaluate our patients' experience of their treatment period with a fixed appliance and their opinions about the results five years after completion of active treatment. A second aim was to assess bonded lingual retainers and their potential side effects. A final aim was to compare the results in a postgraduate clinic (Göteborg) and a specialist clinic (Vänersborg). This study included 170 patients who finished their active treatment in 1997-1998. Eighty-three patients were from Göteborg (postgraduate clinic) and 87 from Vänersborg (specialist clinic). The patients were examined for visible calculus, approximal caries in the anterior regions, gingival recessions and the status of existing retainers in the upper and lower anterior teeth. All patients completed a questionnaire and were interviewed after undergoing a clinical examination. The statistical methods used were descriptive analysis and the chi-square test. The main reason for orthodontic treatment was appearance and most patients (94%) were satisfied with their treatment result. Our results showed a significantly higher frequency of loosened or fractured retainers at the postgraduate clinic compared to the specialist clinic (p < 0.01), which might be explained by operator sensitivity in bonding retainers. There was a tendency for calculus to develop more easily with than without retainers.

CONCLUSION

Patient satisfaction of the treatment given at the postgraduate clinic was the same as at the specialist clinic except for more frequent loosening of bonded retainers.

Allergy to auto-polymerized acrylic resin in an orthodontic patient

This article reports on a 60-year-old woman who had an allergic reaction to methylmethacrylate self-curing acrylic resin during orthodontic treatment. A localized hypersensitive reaction appeared on the palate after an orthodontic retainer was placed. Samples of the acrylic were removed and analyzed with gas chromatography to evaluate the residual monomer level. The residual monomer content was between 0.745% and 0.78%, which did not exceed international standards for this material. Patch tests were performed with several methylmethacrylate resin samples and processed with various techniques; they showed positive reactions. Despite the many alternative products available, self-curing acrylic resin remains widely used because of its low cost, ease of use, and diversity of indications. Orthodontists should be aware that allergic reactions can occur.

Full-thickness flap/subepithelial connective tissue grafting with intramarrow penetrations: three case reports of lingual root coverage

Three case reports are presented that demonstrate the use of full-thickness flap/subepithelial connective tissue grafting for root coverage on the lingual surfaces of the mandibular anterior teeth. This is accomplished using an envelope full-thickness flap technique with intramarrow penetrations at the recipient site. Miller Class I, II, and III gingival recession defects and gingival perforation defects were treated. Complete root coverage was achieved in two Miller Class I gingival recession defects, in one Miller Class II gingival recession defect, and in two gingival perforation defects in areas that exhibited no radiographic evidence of bone loss. Partial root coverage was achieved in two Miller Class III gingival recession defects in an area that exhibited radiographic evidence of bone loss. Although the majority of the exposed root surface was covered in these two Miller Class III defects, about 1 mm of root surface remained exposed, which seemed to closely correspond to the amount of bone loss that was noted radiographically. A grafting technique has been presented that can be used to restore the functional properties of the lingual gingiva of the mandibular anterior teeth by repairing gingival defects and re-establishing the continuity and integrity of the zone of keratinized gingiva. Our clinical impression is that this has made it easier for the three patients presented in this report to maintain the lingual surfaces of the mandibular anterior teeth with routine oral hygiene measures.

Gingival enlargement and resolution during and after orthodontic treatment

Gingival enlargement (GE) is a condition that commonly develops during orthodontic treatment. Thirty adolescent subjects with clinically significant GE were analyzed at pre-orthodontic treatment (T1), when the appliances were removed (T2), and 3 to 12 months after (T3). The mean GE decreased from T2 to T3, but was significantly higher on T3 than T1 (p<.05). It may be concluded that complete resolution of GE developed during orthodontic treatment is not always attained after removal of the fixed appliances.

Comparison of 3 bonded lingual appliances by auditive analysis and subjective assessment

The aim of this prospective study was to compare for the first time the influences of lingual appliances of different dimensions on sound performance and oral comfort. The study group comprised 12 subjects (10 women, 2 men; mean age, 33.96 years). Their sound production was recorded by means of a digital audio tape recorder before, 10 minutes after, and 24 hours after placement of the different appliances for semiobjective assessment by 3 blinded speech professionals. This was followed by supplementary subjective ratings of sound performance and oral comfort by the patients. All lingual appliances induced significant impairment in sound performance and oral comfort. However, they varied significantly with respect to the degree of impairment. The smaller the appliance, the less pronounced the impairments it induced. The smallest changes were induced by a bonded canine-to-canine retainer, followed by customized lingual brackets and prefabricated lingual brackets. By using lower-profile customized brackets, the orthodontist can significantly enhance patient comfort and significantly reduce impairments of sound performance in comparison with prefabricated brackets with larger dimensions. Before placing a lingual appliance, however, patients should be briefed on possible effects such as impaired sound production and decreased oral comfort.

Case report: an unorthodox orthodontic retainer

This case report describes the management of a patient who presented with an interdental eyelet-style retainer placed around maxillary central incisors ten years ago. At that time, the patient underwent orthodontic treatment to close a large maxillary midline diastema. The maxillary central incisors were then crowned to close the small residual midline diastema remaining after the orthodontic treatment. The wire retainer was apparently placed to prevent the diastema from reopening. The patient sought treatment ten years later when pain from necrotic pulps in these central incisors became unbearable.

Periodontal implications of bonded versus removable retainers

Removable retainers have been used by clinicians since the early years of orthodontic practice. During the last decades, an increasing number of cases are retained with bonded lingual retainers. The current study was performed to evaluate whether significant differences in gingival conditions exist between patients who wear removable or fixed retainers. Differences in build-up of plaque and calculus were also investigated. Maxillary and mandibular measurements were taken at baseline (just before debonding) and 1, 3, and 6 months later, from canine to canine on 36 patients. Among these patients, 22 had fixed retainers, and 14 wore removable retainers. The gingival condition was scored according to three parameters: Modified Gingival Index, bleeding on probing, and gingival crevicular fluid flow. After staining with Diaplac, the Plaque Index was registered. The amount of calculus was measured with a calibrated periodontal probe. Gingival inflammation decreased from baseline throughout the entire period of retention. A comparable limited gingival inflammation was found in the presence of both types of retainers. Slightly more plaque and calculus were present on the lingual surfaces in the fixed retainer group. This did not result in more pronounced gingival inflammation than in the removable retainer group, within the evaluated period.

A cautionary tale of simplified retention

Attention is drawn to a possible serious unwanted sequela of a simplified bonded retainer. It is illustrated by three brief case histories.

Effects of retainers on the articulation of speech

Articulation abilities of 15 patients were evaluated at the end of orthodontic treatment with the initiation of removable upper and lower retainer wear. A test of articulation, based on consonants and vowels (cv), (vcv), (vc), (cvc) nonsense syllables, was used to evaluate the articulatory distortions with no retainers and with maxillary and mandibular retainers worn respectively and together. The test was performed (a) on the first day, (b) 24 hours later, and (c) 1 week later. Statistically significant articulatory distortions with the /t/ and /d/ sounds on the first day with upper retainer only and with both retainers worn together were noted. Also significant distortion of the /k/ sound with both retainers worn was observed. These distortions, due to the wearing of retainers, decreased to an insignificant level or disappeared completely on the seventh day showing the ability of tongue adaptation in a very short period of time.