Development of a clinical practice guideline for orthodontic retention

Retention efficacy and patient experience with customized clear retainer and wrap-around circumferential retainer among non-extraction orthodontic patients: A 12-month follow-up cohort study

OBJECTIVE

The aim of this study was to evaluate retention efficacy by assessing retention stability and patient perspectives according to type of circumferential retainer: the wrap-around circumferential retainer (WCR) and customized clear retainer (CCR).

MATERIALS AND METHODS

This cohort follow-up study involved 52 patients aged 18-62 who underwent fixed-appliance orthodontic treatment without extractions or orthognathic surgery. Following screening consenting participants were divided into WCR and CCR groups. All participants before follow-up received fixed retainers for the upper and lower anteriors and respective removable retainers within 2 weeks post-debond. Intraoral scans and lateral cephalograms were taken immediately after debonding (T0) and again 12 months later. Dentoalveolar changes in several measurements were compared to evaluate retention efficacy. Surveys were conducted at 1 month (T1) and 12 months (T2) post-debonding to assess changes in patient experiences. Outcome assessments were blinded. Paired T-tests and independent T-tests were used for intragroup and intergroup comparisons of dentoalveolar measurements, respectively. Survey responses were analysed using the Pearson Chi-Square test.

RESULTS

The final assessment included 32 participants. Model analysis revealed no significant differences between the groups, except for maxillary intermolar width (p = .033). In the WCR group, the cephalometric analysis indicated a significant increase in the incisor mandibular plane angle (p = .002) and a decrease in the interincisal angle (p = .014), while changes in the CCR group were statistically non-significant. Patient attitude evaluation showed similar trends for wear time and overall satisfaction. However, a higher percentage of respondents in the WCR group reported irritation when wearing the retainers (p = .037) at T1 and discomfort related to speech (p = .038) at T2.

CONCLUSIONS

CCR showed better retention efficacy in terms of lower incisor inclination. Patients experienced relatively less irritation and speech discomfort with CCRs.

Evaluation of the use of a clinical practice guideline for external apical root resorption among orthodontists

BACKGROUND

External apical root resorption (EARR) is a frequently observed adverse event in patients undergoing fixed appliance therapy. Assessing the patients' risk during treatment is important, as certain factors are assumed to be associated with an increased likelihood of occurrence. However, their predictive value remains limited, making evidence-based clinical decision-making challenging for orthodontists. To address this issue, the Dutch Association of Orthodontists (NvVO) developed a clinical practice guideline (CPG) for EARR in accordance with the AGREE II instrument (Appraisal of Guidelines for Research and Evaluation II) in 2018. The aim of this study is to get insight into the actual utilization and the practical implementation of the guideline among orthodontists. The hypothesis to be tested was that after its introduction, clinical practice for EARR has changed towards the recommendations in the CPG.

OBJECTIVE

To investigate the use of the 2018 clinical practice guidelines for EARR among orthodontists 3 years after its introduction.

METHODS

A questionnaire using a 7-point Likert scale was developed concerning four domains of EARR described in the guideline. The questionnaire was piloted, finalised, and then distributed digitally among Dutch orthodontists. REDCap was used for data collection, starting with an invitation email in June 2021, followed by two reminders. Effect was tested by the Mann-Whitney U test, and the influence of demographic variables was analysed.

RESULTS

Questionnaires were sent out to all 275 and completed by 133 (response rate 48%); N = 59 females and N = 73 males were included; 81% had their training in the Netherlands, 89% had ≥ 6 years of work experience, and 89% worked in private orthodontic practice. One hundred thirty orthodontists (98.5%) reported changes in clinical practice. The biggest positive change in clinical behaviour regarding EARR occurred if EARR was diagnosed during treatment. Sex, clinical experience, country of specialist training, and working environment of the respondents did not affect clinical practices regarding EARR.

CONCLUSIONS

This questionnaire demonstrated that, 3 years after introduction of the guideline, orthodontists improved their self-reported clinical practices to a more standardised management of root resorption. None of the demographic predictors had a significant effect on the results.

Low translational and rotational movements with 2-point stainless-steel retainers over a period of 1 and 3 years

OBJECTIVES

Long-term stabilization of orthodontic treatment outcomes is an everyday challenge in orthodontics. The use of permanently attached lingual retainers has become gold standard. However, in some cases, patients with fixed lingual retainers show retainer-associated side effects. Aiming to reduce these side effects, clinical knowledge about how tooth and arch form stability adaption takes place over time is important to improve long-term retention protocols. Therefore, the present study aimed to investigate occlusion stability and risks for a newly developing malocclusion in a time-dependent manner in patients being treated with permanent 2‑point steel retainers.

MATERIALS AND METHODS

In this retrospective cohort study, a total of 66 consecutive patients with round stainless-steel retainers were analyzed for postorthodontic occlusion changes after 1 year (group 1, n = 33) and 3 years (group 2, n = 33). Digital Standard Tessellation Language (STL) datasets of the lower jaw were obtained before retainer insertion (T0), and after a 1- (T1) or 3‑year (T2) retention period. Using superimposition software, T1 and T2 situations were compared to T0 regarding rotational and translational changes in tooth positions in all three dimensions.

RESULTS

Occlusion changes were low in both groups. The investigated lower canines were nearly stable in the 1‑ and 3‑year group, although a retention-time-dependent increase in tooth position change of the central and lateral incisors could be observed.

CONCLUSION

The present data provide evidence for time-dependent development of posttherapeutic occlusal adaption limited to central and lateral incisors in patients treated with a 2-point retainer. The observed occlusal changes should be interpreted as an occlusal adaption process rather than severe posttreatment changes associated with the orthodontic retainer.

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.

Evaluation of digital construction, production and intraoral position accuracy of novel 3D CAD/CAM titanium retainers

OBJECTIVES

New opportunities have arisen to manufacture three-dimensional computer-aided design/computer-aided manufacturing (3D CAD/CAM) retainers from titanium blocks by digital cutting technology. These novel technologies need to fulfill requirements regarding digital planning and position accuracy. The aim of the present study was to investigate the digital construction, the CAD/CAM production and the intraoral positioning accuracy of custom-manufactured novel 3D CAD/CAM titanium retainers.

MATERIALS AND METHODS

A total of 37 prime4me® RETAIN3R (Dentaurum, Ispringen, Germany) retainers were inserted to stabilize the upper anterior front teeth. Following insertion, an intraoral scan was used to record the position. The intraoral position was compared to the virtual setup using 3D superimposition software. Measurement points were evaluated in all three dimensions (horizontal, sagittal and vertical planes). Data were analyzed using Kruskal-Wallis test followed by Dunn's multiple comparison test.

RESULTS

A total of 185 measurements were performed. The horizontal plane and the sagittal plane demonstrated a high level of positioning accuracy between the planned and the intraoral position. Statistically significant deviations between the preceding virtual setup and the intraoral situation were observed in the vertical dimension. Within the retainer, the intraoral positioning accuracy decreased for the measurement points in the direction of the distal retainer segment.

CONCLUSION

Based on the results, the present study shows a high level of congruence between the 3D virtually planning and the final intraoral position of the fabricated novel 3D CAD/CAM titanium retainers.

Evaluation of orthodontic retention and retainer content on the Reddit social media website

BACKGROUND

Social media can provide insight into patient experiences with health care. The aim of this study was to evaluate the content regarding orthodontic retention and retainers on the social media website, Reddit.

METHODS

A systematic search for relevant content submitted over a 12-month period on the Reddit forum, r/braces, was conducted. Qualitative analysis of the initial posts for themes and subthemes was conducted by two investigators. Responding comments to the initial posts were assessed for supportiveness for each initial poster and alignment with the evidence-base. Quantitative assessment was via descriptive statistics.

RESULTS

A total of 271 initial posts and 984 comments satisfied the inclusion/exclusion criteria. All initial posts were by patients. Just 1.12% (n = 11) of the comments appeared to be provided by oral health professionals. Most initial posts were negative (50.18%; n = 136), and most comments were positive (70.42%; n = 693). Alignment with the evidence-base was high among the comments (67.89%; n = 668). Eight main themes were identified with concerns regarding the negative impact of retention and retainers on quality of life, compliance with retention protocols and relapse commonly expressed. Concern regarding fear of relapse when waiting for the initial or renewal of retainers was a novel finding. More negative sentiments about orthodontists were expressed than positive.

CONCLUSIONS

Reddit is a supportive and reliable environment for patients regarding orthodontic retention and retainers. The content evaluation suggested deficiencies in communication processes between clinicians and patients. Greater engagement of the orthodontic profession in the provision of supportive and evidence-based information on an individual patient basis and through appropriate information channels is required.

A survey of patient compliance with removable orthodontic retainer wear in Brunei Darussalam

OBJECTIVE

To explore compliance with removable orthodontic retainer wear among patients who had completed fixed appliance orthodontic treatments.

MATERIALS AND METHODS

A cross-sectional online survey was distributed to patients who had completed orthodontic treatment at the government orthodontic clinics. The response rate was 54.9%, 663 questionnaires were distributed and 364 responses were received. Demographic information was collected, and questions regarding types of retainers prescribed, instructed and actual wear times, satisfaction levels, and reasons for wearing and not wearing retainers. Chi Square, Fisher's Exact tests and Independent T-Test were used to detect significant associations between variables.

RESULTS

Respondents under 20 years old and employed were the most compliant. The mean satisfaction levels of Hawley Retainer and Vacuum-Formed Retainer were reported to be 3.7 (P = 0.565). About 28% of those in both groups stated that they wear them to maintain their teeth straight. 32.7% of Hawley retainer wearers reported not wearing their retainers due to speech difficulties.

CONCLUSION

Age and employment status were the variables that determined compliance. There was no significant difference in the satisfaction levels between the two retainer types. Most respondents wear their retainers to keep their teeth straight. Discomfort and forgetfulness were the primary reasons for not wearing retainers, besides speech difficulties.

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.

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.

Effect of self-etch primer application on the bond failure rate of a mandibular bonded lingual retainer

BACKGROUND

The aim of this study was to examine the effect of self-etch primer (SEP) application on the bond failure rate of a mandibular bonded lingual retainer over 24 months.

METHODS

The average age of the 86 individuals included in this study was 17 years 4 months. After the removal of the orthodontic appliances, the lingual retainers, which were made of six-stranded stainless steel wire, were bent and bonded onto the lingual surface of all mandibular anterior teeth. The study was performed using a split-mouth design. In the study group, the SEP was administered to the teeth's lingual surfaces. In the control group, they were etched using 37% phosphoric etchant liquid gel. After etching, the primer was applied. The adhesive resin was applied and the retainer was fitted. The patients were re-evaluated over 24 months. The first bond failures and the amount of adhesive remaining on the tooth were recorded as the adhesive remnant index (ARI) scores. The chi-square test was used to compare the bond failure rates (P = 0.231) and ARI scores between the groups (P = 0.162). The survival rates of the retainers were estimated using the Kaplan-Meier test (P = 0.237). The significance level was P < 0.05.

RESULTS

The bond failure rates, ARI scores, and survival rates did not differ significantly between the groups.

CONCLUSIONS

The results of this study demonstrated that an SEP can be used successfully in mandibular lingual retainer bonding. In situations where saliva isolation is difficult, bonding a fixed lingual retainer with SEP is recommended.

Orthodontic retention experience of university students: A qualitative study

Objective:

To explore university students’ experience of retention and identify potential barriers and facilitators to long-term adherence.

Design:

Cross-sectional qualitative study using virtual focus groups.

Setting:

University of Leeds.

Participants:

Dental and non-dental students from the University of Leeds, who had previously undergone orthodontic treatment and had received removable retainers.

Methods:

Students were invited to participate via email. Virtual focus groups were undertaken using Microsoft Teams. A topic guide was used to explore the experience of orthodontic retention including factors that influence long-term retainer wear. Focus groups were recorded and analysed using an inductive thematic approach.

Results:

In total, 23 students participated in four focus groups, including 13 dental students. The period since the end of orthodontic treatment varied from 9 months to 10 years. Of the 23 participants, 8 (35%) were no longer wearing their retainers. Four themes were identified: (1) experience of orthodontic treatment including knowledge of relapse; (2) experience of retainer wear, including motivators and barriers; (3) role of others; and (4) increasing adherence. Key factors influencing use of retainers were the importance placed on maintaining treatment outcomes, awareness of unwanted tooth movement and understanding of the role of the retainer, access to replacement retainers, and ongoing support to encourage retainer wear. Greater knowledge and dental awareness reported by dental students did not necessarily increase adherence.

Conclusion:

Adherence to removable retainer wear is an important aspect of orthodontic treatment but it is recognised that long-term retainer wear is highly variable. The understanding of relapse and retention is variable. Challenges in gaining access to replacement retainers are a common cause of cessation of retainer wear. Dental professionals are perceived to be important in encouraging and supporting retainer wear and individuals reported they would like more follow-up.

A qualitative meta-synthesis of research into patients' past experiences and perceptions of orthodontic treatment outcomes

BACKGROUND

There is a growing body of evidence emphasizing the importance of research into patient-centred experience in orthodontics. Benefits following orthodontic treatment are mainly related to improved aesthetics and psychosocial outcomes. However, treatment experience from the perspective of orthodontic patients is yet to be fully understood.

OBJECTIVE

To understand the past experiences and current perceptions of treatment outcomes of orthodontic patients.

STUDY DESIGN

A qualitative meta-ethnography.

SELECTION CRITERIA

Qualitative studies and mixed-methods articles with a distinct qualitative component presenting patients' perception of outcomes and overall experiences after an active course of orthodontic treatment were included.

SEARCH METHODS

Comprehensive electronic searches were conducted in MEDLINE, Scopus, Web of Science, PsycINFO, and EMBASE up to May 2021, supplemented by grey literature and manual searches.

DATA COLLECTION AND ANALYSIS

Two independent reviewers were involved in study selection, data extraction, and quality appraisal. The Critical Appraisal Skills Programme tool for qualitative research was used to assess the quality of included studies. Analysis of data was conducted using meta-ethnographic methods.

RESULTS

Out of 801 retrieved search hits, six studies fulfilled the inclusion criteria and were included in the synthesis. The analysis revealed three main themes and associated sub-themes: (1) Reflection on the past treatment experience, (2) Patient satisfaction with treatment outcomes, and (3) Learning to live with retainers.

LIMITATIONS

Results express patients' opinions shortly after treatment, and the long-term impact of orthodontic treatment is yet to be understood.

CONCLUSIONS

Orthodontic patients mainly viewed their experiences and treatment results positively. Desirable aesthetic outcomes, psychosocial outcomes, and satisfaction with smiles were often reported in the studies reviewed. However, some barriers to optimal experiences were noticed concerning orthodontic retention.

REGISTRATION

PROSPERO (CRD42020180121).

Indirect vs direct bonding of mandibular fixed retainers in orthodontic patients: Comparison of retainer failures and posttreatment stability. A 5-year follow-up of a single-center randomized controlled trial

INTRODUCTION

This 2-arm parallel trial aimed to assess the number of failures of mandibular fixed retainers bonded with direct and indirect bonding methods at a 5-year follow-up and investigate the stability of intercanine and interpremolar distances.

METHODS

Consecutive patients from the clinic of the University of Geneva (Switzerland) were randomly allocated to either direct or indirect bonding of a mandibular fixed retainer at the end of orthodontic treatment. Inclusion criteria included the presence of all mandibular incisors and canines; and the absence of active caries, restorations, fractures, or periodontal disease of these teeth. The patients were randomized in blocks of 4 using an online randomization service, with allocation concealment secured by contacting the sequence generator for assignment. Two and 5 years (T5) after bonding the retainers, the patients were recalled, and impressions were taken. The primary outcome was the 5-year survival of the mandibular fixed retainer bonded with both bonding methods. The secondary outcomes were the intercanine and interpremolar distances and the assessment of unexpected posttreatment changes (ie, changes in torque and/or rotations of the mandibular incisors and canines). Blinding was applicable for outcome assessment only. Kaplan-Meier curves were generated, and a Cox proportional hazard regression model was fitted for bonding type, age, and treatment. Linear mixed models were fitted to intercanine and interpremolar distances: bonding type, time, age, and treatment were modeled as outcomes.

RESULTS

Sixty-four patients were randomized in a 1:1 ratio. At T5, 6 patients without previous failure were lost to follow-up from each group. At T5, the fixed retainer was debonded in 14 patients (54%) for each group. The hazard ratio of indirect bonding to direct bonding was 1.09 (95% confidence interval, 0.26-4.60; P = 0.91); there was no statistically significant difference in survival between the groups. Regarding intercanine and interpremolar distances, none of the tested prognostic factors reached statistical significance. Unexpected posttreatment changes were observed in 6 failure-free patients, all bonded with the direct bonding method. Only 1 patient required debonding of the fixed retainer. No other serious harms were observed.

CONCLUSIONS

The 5-year survival rate for both direct and indirect bonding methods was 46%, without a statistically significant difference between bonding methods. Bonded retainers were effective in maintaining intercanine and interpremolar distances. Unexpected posttreatment changes were only observed with retainers bonded with the direct bonding method.

REGISTRATION

The trial was not registered.

PROTOCOL

The protocol was not published before trial commencement.

FUNDING

No funding or conflict of interest to be declared.

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.

Dental changes in humans with untreated normal occlusion throughout lifetime: A systematic scoping review

INTRODUCTION

Understanding age-related changes in normal dental occlusion is crucial for orthodontic treatment, planning, and retention, especially considering the increasing demand from adult patients. This review aimed to systematically perform a scoping literature review regarding age-related dental changes in untreated normal occlusion subjects.

METHODS

An electronic search was performed until May 2020 using the following terms: "Dental Occlusion," "Dentition," "Ageing," and "Age groups." Articles studying changes in dental occlusal traits in orthodontically untreated subjects with neutroclusion and comparing them between various age groups were included. Studies focusing on a single age group or written in languages other than English were excluded. The risk of bias of the studies was assessed with both the methodological index for nonrandomized studies and the risk of bias in nonrandomized studies of intervention tools.

RESULTS

From the initial 7681 articles, 40 were included. High methodologic heterogeneity was found among studies. Intercanine width was found to increase until 8.0 years and 15.0 years in the mandible and maxilla, respectively, whereas intermolar width increases in both arches until 26.0 years. After that, both parameters decrease into late adulthood. Crowding increases from mixed dentition until 60.0 years of age, especially in the mandible and females. Maxillary incisors procline with age while mandibular incisors retroclined.

CONCLUSIONS

The age-related evolution of occlusal traits, together with skeletal and soft tissue changes, should be considered during orthodontic planning. Well-designed prospective cohort studies are necessary for confirmatory evidence. Expectations for treatment stability should consider muscular balance and inform patients that crowding is a sign of aging that should not always be seen as a failure of orthodontic therapy. Protocol registration number: PROSPERO CRD42020138846.

The rationale for orthodontic retention: piecing together the jigsaw

Retaining teeth in their corrected positions following orthodontic treatment is one of the most challenging aspects of orthodontic practice. Despite much research, the rationale for retention is not entirely clear. Teeth tend to revert to their pre-treatment positions due to periodontal and gingival, soft tissue, occlusal and growth factors. Changes may also follow normal dentofacial ageing and are unpredictable with great variability. In this overview, each of these factors are discussed with their implications for retention, along with adjunctive procedures to minimise relapse. The state of current knowledge, methods used to assess relapse, factors regarded as predictive of or associated with stability as well as overcorrection are outlined. Potential areas requiring further investigation are suggested. The way in which the clinician may manage current retention practice, with a need for individualised retention plans and selective retainer wear, is also considered.

How do general dental practitioners perceive and deal with orthodontic bonded retainers?

INTRODUCTION

Long-term follow-up and management of orthodontic bonded retainers require a strong collaboration between orthodontists and general dental practitioners (GDPs). This study aimed to evaluate if Eastern French GDPs were aware of bonded retainers' complications and side effects and if they were willing to take part in their long-term follow-up.

METHODS

Two-hundred and eighteen randomly selected GDPs were invited to answer an online questionnaire. The initial sections covered their experience and management with bonded retainers. In the final sections, GDPs were asked their opinion on the responsibility for long-term follow-up of patients wearing fixed retainers and on the mutual communication between orthodontists and GDPs. Statistical analysis involved descriptive statistics and Fisher exact tests.

RESULTS

Response rate was 32.6% (n = 71). The vast majority of GDPs were familiar with loose retainers, but only 45.2% were willing to repair them. Respondents offering orthodontic services on a regular basis were more likely to insert retainers and repair loose or broken retainers (P < 0.001). Approximately 18.6% of GDPs were aware of third-order side effects encountered with unintentionally active retainers bonded to all 6 anterior teeth. For 88.8% of GDPs, permanent retention was justified, whereas 90% of the dentists refused to be responsible for long-term supervision of fixed retainers. In addition, 67.1% were interested in further training on orthodontic retention, and 92.9% would appreciate clinical guidelines.

CONCLUSIONS

Knowledge about the harmful side effects of bonded retainers was evaluated as insufficient among surveyed GDPs. Long-term follow-up of patients wearing bonded retainers raises issues that should be addressed globally by enhancing mutual communication, practitioners' education, and patients' involvement.

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.

Effect of Photobiomodulation on Relapse in an Experimental Rapid Maxillary Expansion Model in Rat

Rapid maxillary expansion (RME) is performed on transversely deficient maxilla. As all orthodontic treatments, retention is important in maintaining therapeutic outcomes. Fixed /removable retainers are used post-RME causing hygiene and compliance problems. Given photobiomodulation's positive effects on the quantity and quality of bone regeneration, its effect on post-RME relapse was studied. Thirty Sprague Dawley rats were randomly divided into group R, non-irradiated RME-treated (n = 12), group P, irradiated RME-treated (n = 12) and group C, non-RME non-irradiated (n = 6). A 1.5 mm metal ring inserted between maxillary incisors at days 0 and 15 was expanded until 1.5 mm space was obtained at day 30. In group P, Ga-Al-As diode laser (810 nm, 100 mW, 4J/cm² , 30 secs) was applied on days 0, 2, 4, 6, 8, 10, 12 and 14 as predictor variable. The relapse was measured as the space lost between incisors for 30 days after appliance removal (primary outcome variable) and compared with t-test. In week 2, space loss in group P was significantly lower (P < 0.05) than all other groups. The relapse during weeks 2 and 3 was significantly lower in group P than group R. However, no significant difference in relapse amount was found between groups during first and fourth week. There was a significant difference (P < 0.05) between groups in relapse rates (secondary outcome variable) but not in total relapse after 4 weeks. Photobiomodulation proved beneficial in resisting relapse in our study, and it is suggested to be continued until the end of expansion.

In vitro comparison of the torsional load transfer of various commercially available stainless-steel wires used for fixed retainers in orthodontics

OBJECTIVE

To assess the torsional load transfer of various commercially available stainless-steel wires used for fixed retainers.

DESIGN

An in vitro study using a robotic device.

SETTING

Department of Pediatric Oral Health and Orthodontics, University of Basel.

METHODS

A 10° proclination of a maxillary lateral incisor of a 2-2 retainer was simulated with a robotic device. Eight stainless-steel wires with different shapes (round or rectangular), types (plain, braided, coaxial or chain) and dimensions were selected to measure the torsional load transfer at the adjacent central incisor. The influence of annealing was also tested.

RESULTS

The 0.016 × 0.016 and Bond-A-Braid™ wires (0.02645 × 0.01055-inch, 8-stranded, braided) showed the largest relative torsional load transfer (3.7% and 3.3%, respectively). The two multistranded wires - Triple Flex™ and Respond® - showed the smallest values of 1.0% and 0.7%, respectively. The spiral direction of these two multistranded wires affected the load transfer, the twisting showing larger torsional load transfer than the untwisting one.

CONCLUSION

The effective torsional load transfer depends on the dimension, shape and type of a wire. Plain and braided retainers were more predictable in torsional load transfer than multistranded retainers, which may have stored more energy in the area between the composite bonding sites. This may explain the unexpected complications reported in multistranded retainers.

Innovative customized CAD/CAM nickel-titanium lingual retainer versus standard stainless-steel lingual retainer: A randomized controlled trial

Objective

To compare computer-aided design and computer-aided manufacturing (CAD/CAM) customized nitinol retainers with standard stainlesssteel fixed retainers over a 12-month study period.

Methods

This randomized controlled trial (RCT) was conducted on 62 patients randomly allocated to a control group that received stainless-steel retainers or a test group that received customized CAD/CAM nickel-titanium retainers. Four time points were defined: retainer placement (T0) and 1-month (T1), 6-month (T2), and 12-month (T3) follow-up appointments. At each time point, Little's irregularity index (LII) (primary endpoint) and dental stability measurements such as intercanine width were recorded in addition to assessment of periodontal parameters. Radiological measurements such as the incisor mandibular plane angle (IMPA) were recorded at T0 and T3. Failure events (wire integrity or debonding) were assessed at each time point.

Results

From T0 to T3, LII and other dental measurements showed no significant differences between the two groups. The data for periodontal parameters remained stable over the study period, except for the gingival index, which was slightly, but significantly, higher in the test group at T3 (p = 0.039). The IMPA angle showed no intergroup difference. The two groups showed no significant difference in debonding events.

Conclusions

This RCT conducted over a 12-month period demonstrated no significant difference between customized CAD/CAM nickel-titanium lingual retainers and standard stainlesssteel lingual retainers in terms of dental anterior stability and retainer survival. Both retainers eventually appeared to be equally effective in maintaining periodontal health.

Approaches of Turkish Dentists in Cases of Orthodontic Lingual Retainer Failures

OBJECTIVE

This study aimed to investigate the approaches of Turkish dentists in cases of orthodontic lingual retainer failures.

METHODS

A self-administered questionnaire was used to quantify dentists' approaches to lingual retainer failures. The first part of the study investigated the demographic characteristics. In the second part, dentists' approaches to cases of failed retainers were assessed. The third part had questions related to the type of retainers bonded solely to the canines or to all the 6 anterior teeth. Descriptive statistics were done with Pearson's χ2 test, and Mann-Whitney U test was used.

RESULTS

A total of 320 Turkish dentists participated in the survey. Experienced and public dentists preferred to advise the patients whose retainers had failed to contact their orthodontist more frequently (p<0.05). Regarding their approach to patients who requested removal of the bonded retainer, inexperienced dentists more frequently preferred to refer the patients to an orthodontist (p<0.05). With regard to factors affecting the choice to remove a bonded retainer, the most and the least importance were attributed to the orthodontist's opinion and the patient's demand, respectively.

CONCLUSION

Turkish dentists prefer referring their patients to orthodontists rather than performing procedures in cases of failure associated with bonded retainers. Different demographic characteristics seem to have an impact on these approaches.

Could medications and biologic factors affect post-orthodontic tooth movement changes? A systematic review of animal studies

Immediately after the removal of orthodontic appliances, the teeth might start to drift away from their corrected position in an attempt to reach a new equilibrium. Medications and biologic factors could potentially modulate these processes. The objective of the present systematic review is to systematically investigate and appraise the quality of the evidence regarding the effect of various medications and biologic factors on the rate of relapse following active tooth movement. Search without restrictions in eight databases and hand searching until April 2020 were conducted. Studies performed on animal models investigating the effects of medication and biologic factors on the rate of relapse following orthodontic tooth movement were considered. Following study retrieval and selection, relevant data were extracted and the risk of bias was assessed. Seventeen studies were finally identified, mostly at either high or unclear risk of bias. Ketorolac did not show any significant effects on relapse, while the administration of tetracycline, atorvastatin, psoralen and raloxifene decreased it. Overall, the same result was observed with bisphosphonates with the exception of low dosage of risedronate, which did not have an effect. Osteoprotegerin and strontium resulted in reduced relapse, but not in the immediate post-administration period. Inconsistent or conflicting effects were noted after the use of simvastatin and relaxin. The quality of the available evidence was considered at best as low. It can be concluded that specific medications and biologic factors may have an effect on the rate of relapse following tooth movement. The orthodontist should be knowledgeable about the substances potentially affecting retention.

Stability of Class II corrections with removable and fixed functional appliances: A literature review

BACKGROUND

Class II functional appliances have been used in orthodontics for over 100 years. Although the stability of corrections is one of the main goals of orthodontic treatment, there is a paucity of longitudinal studies on the long-term stability of treatment of Class II malocclusion based on functional appliances.

METHODS

This narrative review attempts to summarize the limited related evidence available and discusses the clinical implications of important aspects related to occlusal and skeletal changes that arise after Class II malocclusion treatment with functional appliances.

RESULTS

The occlusal changes obtained through Class II functional treatment do mostly exhibit long-term stability. While mild posttreatment changes occurred, they were most likely due to physiologic aging processes and not likely associated with actual treatment relapse. Long-term retention in the lower jaw would be particularly beneficial. A stable occlusion with good intercuspation in the posterior arches seems more likely to preserve a Class I occlusion after treatment through dentoalveolar compensatory mechanisms. After treatment, the maxilla and the mandible do grow anteriorly, with the mandible growing more than the maxilla. Patients treated with functional appliances are not likely to develop TMJ disorders over the long term.

CONCLUSIONS

Long term skeletal corrections achieved with functional appliances seem to be overall stable. Class II molar and overjet relapses can be likely explained by a combination of tooth movement and an unfavorable posttreatment maxillomandibular growth pattern, especially when combined with unstable interdigitation of the posterior teeth. No specific intermaxillary retention approach has been assessed yet.

Development of a clinical practice guideline for orthodontic retention

OBJECTIVES

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

MATERIALS AND METHODS

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

RESULT

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

LIMITATIONS

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

CONCLUSION

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

A survey of retention and retainer practices of orthodontists in Australia

Objective

To survey retention and retainer practices of orthodontists in Australia.

Methods

A pilot-tested e-survey was distributed to 502 eligible members of the Australian Society of Orthodontists (ASO). The questions addressed participant background information, preferred retainer and retention practices, retainer characteristics and factors influencing retainer choice. Statistical analyses were performed using PASWH version 18.

Results

The response rate was 58%. Thermoplastic retainers (TRs) were the most commonly chosen retainer in the maxilla (39.4%) and bonded retainers (BRs) were most commonly chosen in the mandible (38.5%). An initial period of full-time wear of removable retainers (RRs) was prescribed by 37.7–48.3%. ‘Night/sleeping with reducing frequency over time’ was the most commonly prescribed part-time RR wear practice (28.1-33.5%).

Indefinite retainer wear was recommended by 85.3-87.4% of orthodontists. Indefinite retainer checks were carried out by 19.1-19.8% of orthodontists while 28.9-43.6% were ‘not happy’ for general dental practitioners (GDPs) to continue retention checks. Adjunctive retention practices were used by 25.6-72.8%. Pre-fabrication TR sheet thickness of 1.0 mm (68%) and polypropylene co-polymer/ethylene material type (55.8%) were most commonly used. Vacuum-forming was the preferred mode of TR fabrication by 48.4%. ‘Stainless steel single strand round’ was the most commonly used BR material type (33.4%). BR bonded to 12-22 (bonded to four teeth) was the most common BR design in the maxilla (48.8%) and 33-43 (bonded to six teeth) was most commonly chosen for the mandible (81.5%). Inadvertent tooth movement associated with BRs was observed by 62%. The orthodontist factor that most influenced retainer choice was the nature of the pretreatment malocclusion (88%).

Conclusion

Although there is agreement that retention is indefinite, orthodontic retention practices and retainer characteristics vary considerably between orthodontists in Australia. Greater communication between orthodontists and GDPs is required to effectively manage retention over the long term.