Anterior tooth alignment: A comparison of orthodontic retention regimens 5 years posttreatment

Orthodontic retention: Rationale and periodontal implications

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

Striving for Perfection: How Stable Is Orthodontic Treatment When Excellent Outcomes Are Achieved? A 9-Year Post-Treatment Retrospective Study

(1) Aims: The main objective of this retrospective study was to assess the long-term stability of difficult orthodontic treatments treated to an excellent result and to correlate stability to possible prognostic factors. Secondary objectives were to observe the changes in retention protocol over time and to assess Oral Health-related Quality of Life (OHRQoL) after a long-term post-treatment follow-up. (2) Methods: Cases presented for final examination by orthodontic postgraduate students were retrospectively screened for eligibility. Eligible patients were recalled for a post-treatment recall appointment (T2), consisting of a clinical examination and intraoral scan, and were asked to complete the Oral Health Impact Profile-14 (OHIP-14-DK). Gender, age at treatment commencement (T0), treatment modality and duration, and retention protocol were extracted from the records. At T2, the duration of the retention period was recorded, and retainers in place were clinically compared to the original retention protocol. The following variables were assessed on the sets of models at T0, T1 (end of treatment), and T2: arch length and width, overjet and overbite, Dental Aesthetic Index (DAI), Peer Assessment Rating score (PAR), and Little's Irregularity Index (LII). Multiple regression models were conducted. (3) Results: Eighty-five subjects attended T2. The mean post-treatment follow-up was 9.4 years +/- 2.4. In the upper arch, at T1, 74 patients had a combination of fixed and removable retainers, while at T2, 55 had a fixed retainer only. In the lower arch, at T1, 67 patients had a fixed retainer only, with this number increasing to 76 at T2. From T0 to T1, the PAR score improved by 96.1%, with the improvement remaining at 77.5% at T2. The stability of lower inter-canine and upper inter-premolar widths was significantly correlated with the extent of changes during treatment. The presence of a lower fixed retainer at T2 and a low LII at T1 were prognostic factors for stability. The mean weighted total OHIP-14 score at T2 was very low (1.6 ± 2.4 points). (4) Conclusions: In a sample with an initial high-severity malocclusion and treated to an excellent outcome, long-term stability was very good. Good stability can be retained when a lower fixed retainer is present at T2 and when a low LII is achieved at T1.

Stability of maxillary anterior teeth during retention and 1 year after removal of retention-an RCT on adolescents retained with two different bonded retainers and a vacuum-formed retainer

BACKGROUND

Maxillary bonded and removable retainers maintain teeth in correct positions following orthodontic treatment. There is insufficient evidence regarding the capacity of the retention methods to stabilize the maxillary teeth both during and after retention.

OBJECTIVE

To evaluate retention capacity and 1-year post-retention changes in the irregularity of maxillary anterior teeth and single anterior tooth contact point discrepancy (CPD) of two bonded and one removable retention method.

TRIAL DESIGN

Three-arm parallel group single-centre randomized controlled trial.

METHODS

Ninety adolescent patients treated with fixed orthodontic appliances were enrolled. After gaining informed consent, the patients were randomized in blocks of 30 by an independent person into one of three groups: A) bonded retainer 13-23; B) bonded retainer 12-22; and C) removable vacuum-formed retainer. The primary outcomes were changes in Little's irregularity index (LII) and single CPD measured on digitalized casts before retention (T1), after 2 years of retention (T2), and 1-year post-retention (T3).

BLINDING

The digital casts were blinded for the outcome assessor.

RESULTS

Data on all 90 patients were analysed according to intention-to-treat principles. Changes in LII during retention were 0.3 mm in group A, 0.6 mm in group B, and 1.0 mm in group C. No significant differences between the groups were seen (P > 0.05). Changes during post-retention were 1.1 mm in group A, 0.5 mm in group B, and 0.4 mm in group C. Group A showed more significant changes than groups B and C (P = 0.003). During the whole post-treatment period, no significant differences were shown between the groups (P > 0.05). CPD did not differ significantly between the groups at any point.

HARMS

Three patients showed changes of LII over 3 mm or CPD over 2 mm during the post-retention period, and two accepted to be realigned.

LIMITATIONS

The trial was a single-centre study evaluating 1-year post-retention changes.

CONCLUSIONS

The changes were clinically insignificant during and after the retention period. Thus, all three methods showed equal retention capacity.

TRIAL REGISTRATION

www.clinicaltrials.com (NCT04616755).

The Effect of Third Molars on the Mandibular Anterior Crowding Relapse-A Systematic Review

The present systematic review updates the evidence on wisdom teeth contributing to lower incisor crowding following orthodontic treatment. Relevant literature was searched on online databases, namely Pubmed, Scopus, and Web of Science, up to December 2022. Eligibility criteria were formulated using the PICOS approach and PRISMA guidelines. Eligible research included original clinical studies involving patients previously being treated orthodontically with permanent dentition at the end of treatment, regardless of sex or age. The initial search yielded 605 citations. After considering eligibility criteria and removing duplicates, only 10 articles met the criteria for inclusion. The risk of bias of eligible studies was evaluated using the Cochrane Handbook for Systematic Reviews and Interventions tool. The majority were highly biased, mainly regarding allocation concealment, group similarity, and assessment blinding. The vast majority did not report statistically significant associations between the presence of third molars and crowding relapse. However, a minor effect has been suggested. Seemingly, there is no clear connection between mandibular third molars and incisor crowding after orthodontic treatment. The present review did not find adequate evidence to advocate preventative removal of the third molars for reasons of occlusal stability.

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.

Stability, survival, and patient satisfaction with CAD/CAM versus conventional multistranded fixed retainers in orthodontic patients: a 6-month follow-up of a two-centre randomized controlled clinical trial

OBJECTIVES

The primary aim of this two-arm parallel two-centre randomized controlled trial was to compare computer-aided design and computer-aided manufacturing (CAD/CAM) versus conventional multistranded fixed retainers (FRs) in terms of stability over 6 months. Secondary outcomes were failure rates and patient satisfaction.

METHODS

Patients were randomized to CAD/CAM or conventional FRs in both arches, in 1:1 ratio and blocks of four. Allocation concealment was secured by using sequentially numbered envelopes. Patients were blinded. Retainers were bonded at the end of orthodontic treatment (T0), and patients were recalled after 1 (T1), 3 (T3), and 6 (T6) months. First-time retainer failures were recorded and digital impressions were taken. Arch widths and lengths, as well as Little's Irregularity Index (LII), were measured. Additionally, patients answered satisfaction questionnaires. Linear mixed models were applied for measurements and patient satisfaction. Survival analyses were estimated with Kaplan-Meier curves, along with Cox-regression modelling.

RESULTS

One hundred and eighty-one patients were randomized (98 in Centre 1, and 83 in Centre 2): Ninety in the CAD/CAM group and 91 in the conventional group. Three subjects dropped out at baseline, as they did not attend any of the follow-up appointments.168 patients attended the T6 visit. There were no significant differences in arch dimensions between T0 and T6, whilst the LII was different only in the CAD/CAM group (mean difference: 0.2 mm; 95% confidence interval: 0.1 to 0.4; P < 0.001). Within 6 months, 39 upper retainers (19 out of 88 CAD/CAM and 20 out of 90 conventional retainers) and 52 lower retainers failed (26 out of 88 CAD/CAM and 26 out of 90 conventional retainers), with no significant difference between the survival of both types of retainers (hazard ratios conventional to CAD/CAM: upper arch: 0.99 [P =0.99], lower arch: 0.93 [P = 0.80]). There were no significant changes in patient satisfaction between the groups. No harms were observed.

CONCLUSIONS

There were no clinically significant differences in LII, arch widths and lengths between CAD/CAM and conventional retainers after 6 months. There was no difference in failures and in patient satisfaction between both types of FRs.

REGISTRATION

ClinicalTrials.gov NCT04389879.

Relapse and inadvertent tooth movement post orthodontic treatment in individuals with fixed retainers: A review

Orthodontists must fully inform patients about the implications of orthodontic treatment and the subsequent need for retention. This review provides an update on relapse, unwanted movements and different factors that can cause loss of stability following orthodontic treatment. Since it is difficult to predict which patients will present some degree of loss of stability after treatment, it is important that they be treated as if they have a high potential for relapse. The present review included a bibliographic search in the main sources of scientific review including Medline via PubMed, Scopus and the Cochrane library. The search strategy was carried out until May 5, 2022. Only 34 studies fulfilling the selection criteria. Our results showed that maintaining teeth in the correct position following orthodontic treatment is a great challenge for orthodontists. The etiology of relapse is complex and not yet clearly established. Its origin is attributed to factors such as the time of gingival and periodontal tissue reorganization and changes produced by growth, compromising the stability of the results achieved with orthodontic treatment. The retention phase is necessary after orthodontic treatment to avoid relapse or loss of the occlusion results obtained. However, fixed retainers may induce unwanted tooth movement that may occur despite these retainers being attached and intact. There is currently no consensus among orthodontists regarding the ideal type of wire for fixed containment. We concluded that post-orthodontic treatment relapse is the result of a regression towards the original malocclusion. However, changes in the position of the teeth can also occur, which are considered as unwanted movements and have a multifactorial origin.

Orthodontic Retention-Protocols and Materials-A Questionnaire Pilot Study among Polish Practitioners

The aim of the study was to analyze retention protocols and materials for fixed retainers used by clinicians providing orthodontic treatment in Poland. The survey was carried out from February to April 2021. The questionnaire was designed using the Google Forms tool. After validation, the questionnaire was delivered to verified active orthodontists gathered in a closed social media group of 615 members. Finally, 104 answers were received. Answers to individual questions were provided in percentages and tabularized. A chi-squared test of proportion was used to compare: the proportion of clinicians using retainers of different characteristics and the proportions of clinicians indicating the superiority of a given clinical solution. Rectangular steel braided wire was rated as most reliable. However, doctors who declared to use gold chain were mostly solely using this type of wire. Multistranded round wire was rated the worst. Fiber-reinforced composite was mainly used in periodontal patients. The protocols used by Polish orthodontic practitioners relied on double long-term retention with regular follow-up. The most popular material was stainless steel braided rectangular wire bonded with a flowable composite. Most clinicians believed they could maintain the treatment results, but they declared that patients’ cooperation was a challenge.

Cost analysis of two types of fixed maxillary retainers and a removable vacuum-formed maxillary retainer: a randomized controlled trial

Background

There has been an increased interest in conducting healthcare economic evaluations. Also, orthodontic treatments have gathered focus from an economic point of view, however orthodontic research seldom examines both clinical and economic outcomes.

Objective

To evaluate and compare the costs of three retention methods: a bonded retainer to the maxillary four incisors, a bonded retainer to the maxillary four incisors and canines, and a removable vacuum-formed retainer (VFR) in the maxilla. The null hypothesis was that there was no difference in costs for the three types of retention methods.

Trial design

Three-arm, parallel group, single-centre, randomized controlled trial.

Materials and methods

Ninety adolescent patients, 54 girls and 36 boys, treated with fixed or removable retainers in the maxilla, were recruited to the study. The patients were randomized in blocks of 30, by an independent person, to one of three groups: bonded multistranded PentaOne (Masel Orthodontics) retainer 13-23, bonded multistranded PentaOne (Masel Orthodontics) retainer 12-22, and removable VFR. A cost analysis was made regarding chair time costs based on the costs per hour for the specialist in orthodontics, and material costs plus any eventual costs for repairs of the appliance. Changes in Little’s irregularity index and in single contact point discrepancies (CPDs) were measured on digitalized three-dimensional study casts. Data were evaluated on an intention-to-treat basis. The analysis was performed at 2 years of retention.

Results

No statistically significant difference in costs between the maxillary fixed retainers and the VFRs was found, however, the material and emergency costs were significantly higher for the VFR compared with the bonded retainers. All three retention methods showed equally effective retention capacity, and no statistically significant differences in irregularity or CPDs of the maxillary anterior teeth in the three groups was detected.

Limitations

It was a single-centre trial, and hence less generalizable. Costs depended on local factors, and consequently, cannot be directly transferred to other settings.

Conclusions

All three retention methods can be recommended when considering costs and retention capacity.

Trial registration

NCT04616755.

The influence of 3x3 bonded retainer on anterior crowding relapse in mandibular incisor extraction cases

Objective:

To evaluate the 3x3 bonded retainer influence on the mandibular anterior crowding in cases treated with mandibular incisor extraction

Methods:

The sample comprised pretreatment, posttreatment and follow-up orthodontic records of 16 subjects (10 females and 6 males) with Class I malocclusion treated with extraction of a single mandibular incisor. The mean ages (± SD) at pretreatment, posttreatment and follow-up evaluation were 23.45 ± 9.14 years, 25.50 ± 8.95 years and 30.11 ± 8.59 years, respectively. The mean (± SD) treatment time and posttreatment evaluation time were 2.05 ± 0.45 years and 4.60 ± 1.85 years , respectively. Little irregularity index and interdental widths were evaluated using dental casts. The sample was divided into two subgroups, according to the presence of the 3x3 bonded retainer at follow-up.

Results:

The subgroup without 3x3 bonded retainer presented a greater relapse at the follow-up, when compared to 3x3 bonded retainer subgroup.

Conclusion:

There was a significant relapse in cases treated with mandibular incisor extraction at follow-up. The subgroup without 3x3 bonded retainer showed a significant relapse at the follow-up when compared to the retainer group.

Does quality of orthodontic treatment outcome influence post-treatment stability? A retrospective study investigating short-term stability 2 years after orthodontic treatment with fixed appliances and in the presence of fixed retainers

OBJECTIVE

The present study aimed to evaluate stability 2 years after orthodontic treatment and to investigate the influence of various pre-treatment and post-treatment prognostic factors on stability.

SETTING AND SAMPLE POPULATION

Consecutive patients treated with full fixed appliance and retained with fixed retainers were retrospectively assessed for eligibility.

MATERIALS AND METHODS

Digital models were analysed at treatment start (T0), end of treatment (T1) and 2 years post-treatment (T2). The Peer Assessment Rating (PAR) index, Little's Irregularity Index (LII), arch width and length, overjet, overbite and presence of unexpected post-treatment changes were assessed. Multiple regression analyses were conducted to model the relationship of all outcomes with several prognostics simultaneously.

RESULTS

The sample consisted of 287 subjects (mean treatment time: 25.1 months, standard deviation [SD] 7.5; mean post-treatment follow-up: 27.5 months, SD 6.1) with a mean weighted PAR score of 29.5 (SD 8.6) at T0, 1.8 (SD 2.9) at T1 and 3.2 (SD 3.6) at T2. At T1, 95% of the subjects had a perfect LII versus 86% at T2. An increased LII at T1 correlated with increased LII and PAR changes from T1 to T2. PAR at T1 as well as overjet at T0 was a significant prognostic factor for PAR at T2. At T2, five cases (1.7%) showed unexpected post-treatment changes related to fixed retainers.

CONCLUSION

Short-term post-treatment stability with fixed retainers was very good. Prognostic factors for stability included LII and PAR at T1, suggesting that high-quality treatment outcome in the presence of fixed retainers may ensure post-treatment stability.

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

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS AND ELIGIBILITY CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

RESULTS

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

LIMITATIONS

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

CONCLUSIONS

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

REGISTRATION

Regist0ration number: PROSPERO CRD42020199392.

FUNDING

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

Orthodontist and periodontist's knowledge, attitudes and aspects of clinical practice, regarding fixed lower orthodontic retainers

OBJECTIVE

This study aimed to assess the knowledge, attitudes, and aspects of the clinical practice of orthodontists and periodontists, regarding lower fixed orthodontic retainers.

METHODS

The orthodontists (n=502) and periodontists (n=269) who participated in this cross-sectional observational study received, via e-mail, questions related to the type of lower fixed retainer, dental biofilm accumulation, oral hygiene, and potential periodontal changes. The data were subjected to chi-square and Fisher's exact tests, at 5% significance level.

RESULTS

Both orthodontists (72.3%) and periodontists (58.7%) reported that hygienic retainers accumulate more dental biofilm (p< 0.05), and 64.1% of orthodontists and 58.7% of periodontists considered that modified retainers may lead to periodontal changes (p< 0.05). There was no significant difference between the dental specialties, regarding the type of lower fixed retainer considered the easiest for the patient to perform hygiene (p> 0.05), whereas 48.6% of professionals chose the modified type.

CONCLUSION

The modified retainer accumulates a greater amount of dental biofilm and, in the perception of orthodontists and periodontists, it may cause periodontal changes.

Orthodontic retention protocols: an evidence-based overview

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

Efficiency and outcome quality of Herbst-Multibracket appliance therapy in Class II:2 patients

OBJECTIVES

The aim of this retrospective investigation was to generate representative data on the efficiency and outcome quality of Class II:2 Herbst-Multibracket appliance (Herbst-MBA) treatment.

SUBJECTS AND METHODS

All Class II:2 patients who had started Herbst-MBA treatment at the study centre since 1986 were included. Study casts from before treatment, after Herbst-MBA treatment, and (if available) after ≥24 months of follow-up were evaluated using standard occlusal variables, the Peer Assessment Rating (PAR)-Index, and the Ahlgren-Scale.

RESULTS

During treatment, the pre-treatment PAR score was reduced from 23.6 ± 7.66 to 5.6 ± 3.85 (n = 192); during the follow-up period, a slight increase to 6.0 ± 3.60 occurred (n = 127). The percentage of patients who could be assigned to the PAR category 'greatly improved' was 30% after treatment and 33% after follow-up; only 1%, respectively, 2% had to be assigned to the category 'worse/no different'. The outcome ratings according to the Ahlgren-Scale revealed 20% excellent, 32% good, 46% acceptable, and 2% unsuccessful results.

LIMITATIONS

Retrospective study design with follow-up data not available from all subjects and no data from untreated controls.

CONCLUSIONS

Herbst-MBA is an efficient treatment approach in orthodontic care of Class II:2 malocclusions. High-quality results (mean/median PAR score: 5.6/5.0) with very good short-term stability (2.2 years' follow-up) were achieved. Unfortunately, no appropriate control group or groups, where other treatment approaches had been applied, exist.

Stability of maxillary anterior teeth after 2 years of retention in adolescents: a randomized controlled trial comparing two bonded and a vacuum-formed retainer

BACKGROUND

Retention of the maxillary anterior teeth is commonly recommended to maintain the teeth in their corrected positions. Both fixed and removable retention methods are used, but the certainty of evidence is low.

OBJECTIVE

To evaluate post-treatment changes in irregularity of the maxillary six anterior teeth and single tooth contact point discrepancy (CPD) of three different retention methods.

TRIAL DESIGN

Three-arm parallel group single-centre randomized controlled trial.

MATERIALS AND METHODS

Ninety patients, 54 girls and 36 boys, were recruited to the study. The inclusion criteria were adolescent patients treated with fixed appliances at least in the maxilla. After gaining informed consent from the patient and their custodians, the patients were randomized to one of three groups: bonded retainer 13-23, bonded retainer 12-22, and removable vacuum-formed retainer (VFR) covering the maxillary teeth including the second molars. The randomization, prepared by an independent person, used blocks of 30. The primary outcomes were changes in single CPD and Little's irregularity index (LII) measured on digitalized three-dimensional study casts before and after 2-year retention. The study casts were anonymized before assessment and the changes were blinded for the assessor. Data were evaluated on an intention-to-treat basis. Thus, all randomized patients were incorporated into the final analysis.

RESULTS

The LII and CPDs increased slightly in all three groups without any statistically significant differences between the groups. The VFR group showed a small intercanine width increase and some more changes of canine rotations than in the other groups.

HARMS

No harm was observed in any subjects and none of the patients needed retreatment.

LIMITATIONS

The trial was a single-centre study and short-term changes were evaluated.

CONCLUSIONS

All three retention methods showed equally effective retention capacity and all the changes found in the three groups were small and considered clinically insignificant. Thus, the null hypothesis was confirmed. All three methods can be recommended.

TRIAL REGISTRATION

NCT04616755.

Outcome quality of Class II division 1 Herbst-multibracket appliance treatment: influence of pretreatment Class II severity and skeletal maturity

BACKGROUND

No reliable predictive factors for treatment (Tx) success and outcome quality in Class II:1 Tx have been identified yet.

OBJECTIVE

To assess the influence of pre-Tx Class II severity and skeletal maturity on outcome quality after Herbst-multibracket appliance (MBA) Tx.

SUBJECTS AND METHODS

All Class II:1 patients who completed Herbst-MBA Tx between 1986 and 2014 at University of Giessen, Germany. Pre-Tx (T0), post-Tx (T1), and (if available) post-retention (≥24 months; T2) study casts were evaluated using the Peer Assessment Rating (PAR) index and the Ahlgren scale. Three occlusal severity (mild, moderate, and severe) and four skeletal maturity (pre-peak, peak, post-peak, and adult) subgroup categories were defined.

RESULTS

Four hundred eight-five patients (age at T0: 14.4 ± 3.2 years) could be evaluated; post-retention (T3) data were available for 230 patients. For the total sample, the median PAR score was 32.4 ± 8.85 at T0, 8.0 ± 4.52 at T1, and 8.8 ± 5.11 at T2. Very low correlations between the subgroup categories (occlusal severity/skeletal maturity) and PAR-score reduction were detected both during Tx (r = 0.12/r = 0.05) and the total observation period (r = 0.17/r = 0.03). The overall outcome quality according to Ahlgren was: 17.0% excellent, 34.8% good, 43.8% acceptable, 2.2% unacceptable, and 2.2% not assessable. The association with the subgroup categories was: p = 0.019 (occlusal severity)/p = 0.820 (skeletal maturity).

LIMITATIONS

Retrospective study design with follow-up data was not available from all subjects and no data from untreated controls. Tx was performed by several physicians using different kind of MBAs.

CONCLUSION

Class II:1 Herbst-MBA Tx is an effective and successful Tx approach irrespective of pre-Tx skeletal maturity but dependent-to a certain extent-on Class II severity. Thus, when considering a Herbst appliance for Class II correction, neither of the two variables should considerably limit the indication.

Stability of Class II malocclusion treatment with the distal jet followed by fixed appliances

INTRODUCTION

This retrospective study aimed to assess the stability of Class II malocclusion treatment with the distal jet, followed by fixed appliances.

METHODS

Seventy-five cephalograms of 30 subjects were divided into 2 groups. The treated group consisted of 15 patients who were evaluated at the pretreatment, posttreatment, and long-term posttreatment stages. The control group consisted of 15 subjects with normal occlusion, comparable to the experimental group at the long-term posttreatment period. Intergroup comparison of posttreatment changes was evaluated with t tests.

RESULTS

In the long-term posttreatment period, there was no significant change in the anteroposterior position of the maxilla and mandible to the cranial base. The lower anterior face height had a significantly smaller increase in the treated than in the control group. The maxillary molars in the treated group had significantly smaller vertical development, and the mandibular incisors had significantly greater labial tipping and protrusion than the control group. The treatment produced significant improvement in molar relationship and reduction of overbite and overjet, which remained stable in the long-term posttreatment period. There was greater upper lip protrusion in the experimental than in the control group in the long-term posttreatment period.

CONCLUSIONS

Treatment of Class II malocclusions with the distal jet, followed by fixed appliances, showed good long-term stability in molar relationship, overbite, and overjet.

Teeth movement 12 years after orthodontic treatment with and without retainer: relapse or usual changes?

Aims

To identify if lower incisor movements after orthodontic treatment are due to the relapse of the orthodontic treatment or due to natural growth.

Subjects and methods

The subjects consisted of 92 patients who have had orthodontic treatment, divided into three groups, group 1: 38 individuals had no retainer in the lower jaw. Group 2: 24 individuals had a retainer 0.028 inch, a spring hard wire bonded to the mandibular canines only. Group 3: 30 individuals had a 0.0195-inch Twist-Flex wire, bonded to all mandibular incisors and canines. Study models before orthodontic treatment (T0), immediately after orthodontic treatment (T1), 6 years after orthodontic treatment (T2), and 12 years after orthodontic treatment (T3) were used for the measurements. The wires in groups 2 and 3 were removed after mean 2.6 years (SD 1.49). Little Irregularity Index (LII), inter-canine distance, available mandibular anterior space, and number of crowded incisors were registered. A Tooth Displacement Index (TDI) was developed to measure the tooth displacement directions at T0 and T3.

Results

The LII showed equal values before treatment (T0) and at the follow-up registrations (T2 and T3). But about 25 per cent of the tooth displacements at T2 and T3 did not exist before treatment, at T0. This indicates usual growth changes and not relapse of the orthodontic treatment.

Conclusion

As about 25 per cent of the displaced incisors can be considered as an effect of natural growth, not a relapse of the orthodontic treatment, it is valuable to use a displacement index in combination with other variables for investigations of stability after orthodontic treatment. Importance of the present study is that it is possible to differ between relapse and usual growth changes.

A survey of general dentists regarding orthodontic retention procedures

AIM

To explore 1. how Swiss general dentists deal with complications associated with fixed orthodontic retainers, 2. collaboration between general dentists and orthodontists with regards to the organization and responsibility for long-term follow-up of orthodontic retainers, and 3. the need for standardized clinical guidelines regarding orthodontic retention.

METHODS

A structured questionnaire was sent to 201 randomly selected dentists. They were asked about their experience with retainers, opinions regarding the advantages and disadvantages of different types of retainers, responsibility for patients wearing bonded retention and the communication between orthodontists and general dentists. Statistical analysis was carried out using SPSS software.

RESULTS

The response rate was 61 per cent. About 55 per cent of the respondents had had experience with bonding fixed retainers and even more were familiar with their follow-up and repair. In case of complications, dentists usually contacted orthodontists according to the following rule: the more severe the complication, the more intense the communication. Most dentists hesitated to remove retainers when requested to do so by the patient and attempted to convince them to continue wearing them. Retainers bonded to all six anterior teeth were considered more efficient than those bonded to canines only; however, possible side effects (e.g. unwanted changes of the torque) were not well known. 66.4 per cent respondents were willing to take responsibility for patients in retention as early as 6 months after retainer placement. 93.2 per cent respondents would welcome the establishment of standardized guidelines.

CONCLUSIONS

Swiss general dentists have good knowledge of orthodontic retention and follow-up procedures. Nevertheless, introduction of clinical guidelines including information on the possible side-effects of bonded retention is justified.