Free-breathing 3D whole-heart joint T1/T2 mapping and water/fat imaging at 0.55 T.

PURPOSE: To develop and validate a highly efficient motion compensated free-breathing isotropic resolution 3D whole-heart joint T1/T2 mapping sequence with anatomical water/fat imaging at 0.55 T. METHODS: The proposed sequence takes advantage of shorter T1 at 0.55 T to acquire three interleaved water/fat volumes with inversion-recovery preparation, no preparation, and T2 preparation, respectively. Image navigators were used to facilitate nonrigid motion-compensated image reconstruction. T1 and T2 maps were jointly calculated by a dictionary matching method. Validations were performed with simulation, phantom, and in vivo experiments on 10 healthy volunteers and 1 patient. The performance of the proposed sequence was compared with conventional 2D mapping sequences including modified Look-Locker inversion recovery and T2-prepared balanced steady-SSFP sequence. RESULTS: The proposed sequence has a good T1 and T2 encoding sensitivity in simulation, and excellent agreement with spin-echo reference T1 and T2 values was observed in a standardized T1/T2 phantom (R2 = 0.99). In vivo experiments provided good-quality co-registered 3D whole-heart T1 and T2 maps with 2-mm isotropic resolution in a short scan time of about 7 min. For healthy volunteers, left-ventricle T1 mean and SD measured by the proposed sequence were both comparable with those of modified Look-Locker inversion recovery (640 ± 35 vs. 630 ± 25 ms [p = 0.44] and 49.9 ± 9.3 vs. 54.4 ± 20.5 ms [p = 0.42]), whereas left-ventricle T2 mean and SD measured by the proposed sequence were both slightly lower than those of T2-prepared balanced SSFP (53.8 ± 5.5 vs. 58.6 ± 3.3 ms [p < 0.01] and 5.2 ± 0.9 vs. 6.1 ± 0.8 ms [p = 0.03]). Myocardial T1 and T2 in the patient measured by the proposed sequence were in good agreement with conventional 2D sequences and late gadolinium enhancement. CONCLUSION: The proposed sequence simultaneously acquires 3D whole-heart T1 and T2 mapping with anatomical water/fat imaging at 0.55 T in a fast and efficient 7-min scan. Further investigation in patients with cardiovascular disease is now warranted.

Retention procedures for stabilising tooth position after treatment with orthodontic braces.

BACKGROUND: Without a phase of retention after successful orthodontic treatment, teeth tend to 'relapse', that is, to return to their initial position. Retention is achieved by fitting fixed or removable retainers to provide stability to the teeth while avoiding damage to teeth and gums. Removable retainers can be worn full- or part-time. Retainers vary in shape, material, and the way they are made. Adjunctive procedures are sometimes used to try to improve retention, for example, reshaping teeth where they contact ('interproximal reduction'), or cutting fibres around teeth ('percision'). This review is an update of one originally published in 2004 and last updated in 2016. OBJECTIVES: To evaluate the effects of different retainers and retention strategies used to stabilise tooth position after orthodontic braces. SEARCH METHODS: An information specialist searched Cochrane Oral Health Trials Register, CENTRAL, MEDLINE, Embase and OpenGrey up to 27 April 2022 and used additional search methods to identify published, unpublished and ongoing studies.  SELECTION CRITERIA: Randomised controlled trials (RCTs) involving children and adults who had retainers fitted or adjunctive procedures undertaken to prevent relapse following orthodontic treatment with braces. We excluded studies with aligners. DATA COLLECTION AND ANALYSIS: Two review authors independently screened eligible studies, assessed risk of bias and extracted data. Outcomes were stability or relapse of tooth position, retainer failure (i.e. broken, detached, worn out, ill-fitting or lost), adverse effects on teeth and gums (i.e. plaque, gingival and bleeding indices), and participant satisfaction. We calculated mean differences (MD) for continuous data, risk ratios (RR) or risk differences (RD) for dichotomous data, and hazard ratios (HR) for survival data, all with 95% confidence intervals (CI). We conducted meta-analyses when similar studies reported outcomes at the same time point; otherwise results were reported as mean ranges. We prioritised reporting of Little's Irregularity Index (crookedness of anterior teeth) to measure relapse, judging the minimum important difference to be 1 mm. MAIN RESULTS: We included 47 studies, with 4377 participants. The studies evaluated: removable versus fixed retainers (8 studies); different types of fixed retainers (22 studies) or bonding materials (3 studies); and different types of removable retainers (16 studies). Four studies evaluated more than one comparison. We judged 28 studies to have high risk of bias, 11 to have low risk, and eight studies as unclear.  We focused on 12-month follow-up.  The evidence is low or very low certainty. Most comparisons and outcomes were evaluated in only one study at high risk of bias, and most studies measured outcomes after less than a year. Removable versus fixed retainers Removable (part-time) versus fixed   One study reported that participants wearing clear plastic retainers part-time in the lower arch had more relapse than participants with multistrand fixed retainers, but the amount was not clinically significant (Little's Irregularity Index (LII) MD 0.92 mm, 95% CI 0.23 to 1.61; 56 participants). Removable retainers were more likely to cause discomfort (RR 12.22; 95% CI 1.69 to 88.52; 57 participants), but were associated with less retainer failure (RR 0.44, 95% CI 0.20 to 0.98; 57 participants) and better periodontal health (Gingival Index (GI) MD -0.34, 95% CI -0.66 to -0.02; 59 participants). Removable (full-time) versus fixed   One study reported that removable clear plastic retainers worn full-time in the lower arch did not provide any clinically significant benefit for tooth stability over fixed retainers (LII MD 0.60 mm, 95% CI 0.17 to 1.03; 84 participants). Participants with clear plastic retainers had better periodontal health (gingival bleeding RR 0.53, 95% CI 0.31 to 0.88; 84 participants), but higher risk of retainer failure (RR 3.42, 95% CI 1.38 to 8.47; 77 participants). The study found no difference between retainers for caries.  Different types of fixed retainers Computer-aided design/computer-aided manufacturing (CAD/CAM) nitinol versus conventional/analogue multistrand One study reported that CAD/CAM nitinol fixed retainers were better for tooth stability, but the difference was not clinically significant (LII MD -0.46 mm, 95% CI -0.72 to -0.21; 66 participants). There was no evidence of a difference between retainers for periodontal health (GI MD 0.00, 95% CI -0.16 to 0.16; 2 studies, 107 participants), or retainer survival (RR 1.29, 95% CI 0.67 to 2.49; 1 study, 41 participants). Fibre-reinforced composite versus conventional multistrand/spiral wire  One study reported that fibre-reinforced composite fixed retainers provided better stability than multistrand retainers, but this was not of a clinically significant amount (LII MD -0.70 mm, 95% CI -1.17 to -0.23; 52 participants). The fibre-reinforced retainers had better patient satisfaction with aesthetics (MD 1.49 cm on a visual analogue scale, 95% CI 0.76 to 2.22; 1 study, 32 participants), and similar retainer survival rates (RR 1.01, 95% CI 0.84 to 1.21; 7 studies; 1337 participants) at 12 months. However, failures occurred earlier (MD -1.48 months, 95% CI -1.88 to -1.08; 2 studies, 103 participants; 24-month follow-up) and more gingival inflammation at six months, though bleeding on probing (BoP) was similar (GI MD 0.59, 95% CI 0.13 to 1.05; BoP MD 0.33, 95% CI -0.13 to 0.79; 1 study, 40 participants). Different types of removable retainers Clear plastic versus Hawley When worn in the lower arch for six months full-time and six months part-time, clear plastic provided similar stability to Hawley retainers (LII MD 0.01 mm, 95% CI -0.65 to 0.67; 1 study, 30 participants). Hawley retainers had lower risk of failure (RR 0.60, 95% CI 0.43 to 0.83; 1 study, 111 participants), but were less comfortable at six months (VAS MD -1.86 cm, 95% CI -2.19 to -1.53; 1 study, 86 participants). Part-time versus full-time wear of Hawley There was no evidence of a difference in stability between part-time and full-time use of Hawley retainers (MD 0.20 mm, 95% CI -0.28 to 0.68; 1 study, 52 participants). AUTHORS' CONCLUSIONS: The evidence is low to very low certainty, so we cannot draw firm conclusions about any one approach to retention over another. More high-quality studies are needed that measure tooth stability over at least two years, and measure how long retainers last, patient satisfaction and negative side effects from wearing retainers, such as tooth decay and gum disease.

ANTECEDENTES: Sin una fase de retención tras un tratamiento de ortodoncia exitoso, los dientes tienden a "recaer", es decir, a volver a su posición inicial. La retención se consigue colocando retenedores fijos o removibles para proporcionar estabilidad a los dientes y evitar al mismo tiempo daños en dientes y encías. Los retenedores removibles pueden llevarse a tiempo completo o parcial. Los retenedores varían en la forma, el material y el modo de fabricación. A veces se utilizan procedimientos complementarios para intentar mejorar la retención, por ejemplo, remodelando los dientes en la zona de contacto ("reducción interproximal") o cortando fibras alrededor de los dientes ("pericisión"). Esta revisión es una actualización de una publicada originalmente en 2004 y actualizada por última vez en 2016. OBJETIVOS: Evaluar los efectos de los diferentes retenedores y estrategias de retención utilizados para estabilizar la posición de los dientes después del tratamiento con aparatos de ortodoncia. MÉTODOS DE BÚSQUEDA: Un documentalista realizó búsquedas en el Registro de ensayos del Grupo Cochrane de Salud oral (Cochrane Oral Health), en CENTRAL, MEDLINE, Embase y OpenGrey hasta el 27 de abril de 2022 y utilizó métodos de búsqueda adicionales para identificar estudios publicados, no publicados y en curso. CRITERIOS DE SELECCIÓN: Ensayos controlados aleatorizados (ECA) con niños y adultos a los que se les colocaron retenedores o se les realizaron procedimientos complementarios para prevenir la recaída tras el tratamiento con aparatos de ortodoncia. Se excluyeron los estudios con alineadores. OBTENCIÓN Y ANÁLISIS DE LOS DATOS: Dos autores de la revisión realizaron de forma independiente la revisión de los estudios elegibles, evaluaron el riesgo de sesgo y extrajeron los datos. Los desenlaces fueron la estabilidad o recaída de la posición dental, el fracaso del retenedor (es decir, roto, desprendido, desgastado, mal ajustado o perdido), los efectos adversos en dientes y encías (es decir, índices de placa, gingivales y de sangrado) y la satisfacción de los participantes. Se calcularon las diferencias de medias (DM) para los datos continuos, las razones de riesgos (RR) o las diferencias de riesgos (DR) para los datos dicotómicos, y los cociente de riesgos instantáneos (CRI) para los datos de supervivencia, todos ellos con intervalos de confianza (IC) del 95%. Se realizaron metanálisis cuando estudios similares informaron desenlaces en el mismo punto temporal; de lo contrario, los resultados se informaron como rangos medios. Se dio prioridad a la notificación del Little's Irregularity Index (torcedura de los dientes anteriores) para medir la recaída, considerando que la diferencia mínima importante era de 1 mm. RESULTADOS PRINCIPALES: Se incluyeron 47 estudios con 4377 participantes. Los estudios evaluaron: retenedores removibles versus fijos (ocho estudios); diferentes tipos de retenedores fijos (22 estudios) o materiales adhesivos (tres estudios); y diferentes tipos de retenedores removibles (16 estudios). Cuatro estudios evaluaron más de una comparación. Se consideró que 28 estudios tenían un alto riesgo de sesgo, 11 un riesgo bajo y en ocho estudios fue incierto. El centro de atención de esta revisión fue el seguimiento a los 12 meses. La evidencia es de certeza baja a muy baja. La mayoría de las comparaciones y los desenlaces se evaluaron en un solo estudio con alto riesgo de sesgo, y la mayoría de los estudios midieron los desenlaces después de menos de un año. Retenedores removibles versus fijos Removible (a tiempo parcial) versus fijo Un estudio informó que los participantes que llevaban retenedores de plástico transparente a tiempo parcial en la arcada inferior presentaron más recaídas que los participantes con retenedores fijos de múltiples barras, pero la cantidad no fue clínicamente significativa (Little's Irregularity Index [IIL] DM 0,92 mm; IC del 95%: 0,23 a 1,61; 56 participantes). Los retenedores removibles tuvieron más probabilidades de causar molestias (RR 12,22; IC del 95%: 1,69 a 88,52; 57 participantes), pero se asociaron con menos fracaso del retenedor (RR 0,44; IC del 95%: 0,20 a 0,98; 57 participantes) y mejor salud periodontal (Gingival Index [IG] DM ­0,34; IC del 95%: ­0,66 a ­0,02; 59 participantes). Removible (a tiempo completo) versus fijo Un estudio informó que los retenedores removibles de plástico transparente utilizados a tiempo completo en la arcada inferior no proporcionaron efectos beneficiosos clínicamente significativos en la estabilidad dental en comparación con los retenedores fijos (LII DM 0,60 mm; IC del 95%: 0,17 a 1,03; 84 participantes). Los participantes con retenedores de plástico transparente tenían mejor salud periodontal (sangrado gingival RR 0,53; IC del 95%: 0,31 a 0,88; 84 participantes), pero mayor riesgo de fracaso del retenedor (RR 3,42; IC del 95%: 1,38 a 8,47; 77 participantes). El estudio no encontró diferencias entre los retenedores en las caries. Diferentes tipos de retenedores fijos De nitinol con diseño asistido por ordenador/fabricación asistida por ordenador (DAO/FAO) versus de múltiples barras convencional/analógico Un estudio informó que los retenedores fijos de nitinol con DAO/FAO fueron mejores para la estabilidad dental, pero la diferencia no fue clínicamente significativa (LII DM ­0,46 mm; IC del 95%: ­0,72 a ­0,21; 66 participantes). No hubo evidencia de una diferencia entre los retenedores en la salud periodontal (GI MD 0,00; IC del 95%: ­0,16 a 0,16; dos estudios, 107 participantes) ni en la supervivencia del retenedor (RR 1,29; IC del 95%: 0,67 a 2,49; un estudio, 41 participantes). Composite reforzado con fibra versus alambre de múltiples barras/en espiral convencional Un estudio informó que los retenedores fijos de composite reforzado con fibra proporcionaron una mayor estabilidad que los retenedores de múltiples barras, pero no fue clínicamente significativa (LII DM ­0,70 mm; IC del 95%: ­1,17 a ­0,23; 52 participantes). Los retenedores reforzados con fibra tuvieron una mejor satisfacción del paciente con respecto a la estética (DM 1,49 cm en una escala visual analógica; IC del 95%: 0,76 a 2,22; un estudio, 32 participantes) y tasas similares de supervivencia del retenedor (RR 1,01, IC del 95%: 0,84 a 1,21; siete estudios; 1337 participantes) a los 12 meses. Sin embargo, los fracasos se produjeron antes (DM ­1,48 meses; IC del 95%: ­1,88 a ­1,08; dos estudios, 103 participantes; seguimiento de 24 meses) y más inflamación gingival a los seis meses, aunque el sangrado al sondaje (SS) fue similar (GI DM 0,59; IC del 95%: 0,13 a 1,05; SS DM 0,33; IC del 95%: ­0,13 a 0,79; un estudio, 40 participantes). Diferentes tipos de retenedores removibles Plástico transparente versus Hawley Cuando se llevó en la arcada inferior durante seis meses a tiempo completo y seis meses a tiempo parcial, el plástico transparente proporcionó una estabilidad similar a los retenedores Hawley (LII DM 0,01 mm; IC del 95%: ­0,65 a 0,67; un estudio, 30 participantes). Los retenedores Hawley tuvieron un menor riesgo de fracaso (RR 0,60; IC del 95%: 0,43 a 0,83; un estudio, 111 participantes), pero resultaron menos cómodos a los seis meses (EVA DM ­1,86 cm; IC del 95%: ­2,19 a ­1,53; un estudio, 86 participantes). Hawley a tiempo parcial versus a tiempo completo No hubo evidencia de una diferencia en la estabilidad entre el uso a tiempo parcial y a tiempo completo de los retenedores Hawley (DM 0,20 mm; IC del 95%: ­0,28 a 0,68; un estudio, 52 participantes). CONCLUSIONES DE LOS AUTORES: La evidencia es de certeza baja a muy baja, por lo que no fue posible establecer conclusiones firmes sobre un método de retención en detrimento de otro. Se necesitan más estudios de alta calidad que midan la estabilidad de los dientes durante al menos dos años, así como la duración de los retenedores, la satisfacción de los pacientes y los efectos secundarios negativos del uso de retenedores, como caries y enfermedades de las encías.

Tooth loss as a result of a bonded retainer: a case report.

To reduce the risk of unwanted post-treatment changes following orthodontic treatment, use of bonded retainers is gaining popularity. Despite their efficacy and popularity with patients, it has been widely reported that there are significant risks with bonded retainers if they are not maintained and monitored. This case report demonstrates how unwanted tooth movement caused by a bonded retainer can lead to catastrophic failure and ultimately, tooth loss. The importance of active and regular monitoring of bonded retainers is highlighted and recommendations are made to the wider dental community on how to monitor such retainers in clinical practice.

Patient perceptions and attitudes regarding post-orthodontic treatment changes.

OBJECTIVES: To determine patient perceptions and attitudes regarding posttreatment changes at least 2 years after completion of orthodontic treatment. MATERIALS AND METHODS: A total of 125 patients (75 females, 50 males, aged 22.93 ± 2.98 years) were enrolled at least 2 years after debonding. Participants had either vacuum-formed retainers (VFRs) or bonded retainers (BRs). Posttreatment changes were evaluated digitally by comparing tooth positions at debonding and at least 2 years after debonding. A questionnaire was used to assess patient attitudes. Retainer usage, awareness of relapse, satisfaction with their current occlusion, and whether posttreatment changes were severe enough for them to consider retreatment were investigated. RESULTS: All patients showed some posttreatment changes in irregularity. Only 74% of patients wearing VFRs and 47.1% of patients wearing BRs were aware of posttreatment changes. Patients were more likely to notice posttreatment changes if there was an increase in mandibular irregularity of 1-3 mm. Awareness of posttreatment changes in the upper arch was higher in both groups. The majority of participants were satisfied with the results even if they noticed some minor posttreatment changes (VFR, 69.4%; BR, 76.5%). Dissatisfaction with posttreatment changes did not necessarily mean that a patient wanted retreatment. CONCLUSIONS: A total of 26% of patients wearing VFRs and 52.9% of patients wearing BRs were unaware of posttreatment changes. Approximately half of the patients who noticed posttreatment changes were still satisfied with the result 2 years after debonding. Even patients dissatisfied with the effect of posttreatment changes do not necessarily want retreatment.

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.

CAD/CAM nitinol bonded retainer versus a chairside rectangular-chain bonded retainer: A multicentre randomised controlled trial.

BACKGROUND: Bonded retainers are widely used to maintain the positions of anterior teeth after orthodontic treatment. Various types of bonded retainer exist however, there is a lack of evidence to indicate which type is superior. AIM: To compare upper and lower CAD/CAM nitinol bonded retainers (Memotain®) with upper and lower chairside rectangular-chain bonded retainers (Ortho-FlexTech™), in terms of stability, retainer failures and patient satisfaction. TRIAL DESIGN: Multi-centre, two-arm, parallel-group, randomised controlled clinical trial with 1:1 allocation. SETTING: Three trial centres: University Teaching Hospital; District General Hospital; and Specialist Orthodontic Practice. All treatment was provided free as part of a state-funded healthcare system. MATERIALS AND METHODS: A total of 68 patients were randomly allocated to receive either upper and lower Memotain® bonded retainers or upper and lower Ortho-FlexTech™ bonded retainers. Ten trained operators placed and reviewed the bonded retainers. Measurements were carried out on study models taken at debond and after six months. Patient satisfaction questionnaires were completed at six months following debond. RESULTS: The trial was terminated due to the high number of failures (50%) of the upper Memotain® retainers within six months. Memotain® retainers were three times more likely to fail (unadjusted hazard ratio = 2.82, 95% confidence interval = 1.00-7.99) than Ortho-FlexTech™ retainers at six months in the upper arch. Patients were satisfied with both types of retainer. LIMITATIONS: Early termination of the trial means that the a priori sample size was not reached, so outcomes should be interpreted with caution. CONCLUSION: The trial was terminated early due to the high failure rate of upper Memotain® bonded retainers. They had a higher risk of failure in the maxillary arch when compared to upper Ortho-FlexTech™ bonded retainers after six months.

Study protocol for the management of impacted maxillary central incisors: a multicentre randomised clinical trial: the iMAC Trial.

BACKGROUND: Failure of eruption of the maxillary permanent incisor teeth usually presents in the mixed dentition between the ages of 7 and 9 years. Missing and unerupted maxillary incisors can be regarded as unattractive and have a potentially negative impact on facial and dental aesthetics. The presence of a supernumerary tooth (or odontoma) is commonly responsible for failed eruption or impaction of the permanent maxillary incisors. The primary objective of this trial is to investigate the success of eruption associated with maxillary incisor teeth that have failed to erupt because of a supernumerary tooth in the anterior maxilla. METHODS: This protocol describes an interventional multicentre two-arm randomised clinical trial. Participants meeting the eligibility criteria will be randomised (unrestricted equal participant allocation [1:1]) to either space creation with an orthodontic appliance, removal of the supernumerary tooth and application of direct orthodontic traction or space creation with an orthodontic appliance, removal of the supernumerary tooth and monitoring. The primary outcome of this trial is to determine the prevalence of successfully erupted maxillary central permanent incisors at 6 months following removal of the supernumerary tooth. Secondary outcome measures include (1) the effect of initial tooth position (assessed radiographically) on time taken for the tooth to erupt, (2) time taken to align the unerupted tooth to the correct occlusal position, (3) gingival aesthetics and (4) changes in the self-reported Oral Health Related-Quality of Life (OHRQoL) (pre-and post-treatment). DISCUSSION: There is a lack of high-quality robust prospective studies comparing the effectiveness of interventions to manage this condition. Furthermore, the UK national clinical guidelines have highlighted a lack of definitive treatment protocols for the management of children who present with an unerupted maxillary incisor due to the presence of a supernumerary tooth. The results of this trial will inform future treatment guidelines for the management of this condition in young children. TRIAL REGISTRATION: ISRCTN Registry ISRCTN12709966 . Registered on 16 June 2022.

The effect of different bonded retainer wires on tooth mobility immediately after orthodontic treatment.

OBJECTIVES: This study aimed to compare the immediate influence of four commonly used retainer wires on tooth mobility following orthodontic treatment with fixed appliances. MATERIALS AND METHODS: Eighty patients after orthodontic treatment were assigned to four study groups (n = 20 in each group). Groups were provided with directly bonded fixed retainers-0.0150″ (group A), 0.0175″ (group B), 0.016 × 0.022″ (group C), and 0.0215″ (group D). Tooth mobility was measured using the Periotest device at two times-after removal of fixed appliance (T1) and after bonding of the retainer (T2). Values of tooth mobility, 'Periotest values', were analysed between groups and compared with the physiologic tooth mobility in a control group of untreated patients (n = 65). Kruskal-Wallis H, Mann-Whitney U, Dunn's test, Fisher's exact test, and binary logistic regression tests were used to analyze the data. RESULTS: Tooth mobility after orthodontic treatment was significantly increased. While canines remained within normal range of tooth mobility, values for incisors increased on average to the first degree of tooth mobility (slight mobility). Logistic regression analysis identified age as a significant predictor for increased tooth mobility (P = 0.032) with odds ratio 1.065 (95% CI 1.005-1.128), with mobility increasing with age. After bonding of the retainer in all four groups, the tooth mobility was reduced to values which were not significantly different form normal physiological values found in the control group (P > 0.05). There were no differences in the amount of change or in tooth mobility values at T2 between the different types of bonded retainers. LIMITATIONS: Age of subjects in the control group was significantly higher than that in the study groups. An alternation method was used instead of randomization to distribute the four different types of retainers. CONCLUSIONS: All of the retainer wires were able to successfully reduce the increased tooth mobility caused by orthodontic treatment to normal levels. The values of tooth mobility after placement of retainers were within the range of physiologic tooth mobility.

Fixed retention: pitfalls and complications.

Long-term stability of orthodontic treatment results is problematic. Long-term or even lifelong retention with bonded retainers is being increasingly used among clinicians. Bonded retainers can provide an efficient and attractive method of retention, particularly because they require minimal compliance from patients. However, the use of bonded retainers is associated with relatively frequent complications, such as detachments of the adhesive layer or wire fractures, as well as unexpected complications with potentially severe consequences with associated periodontal and general health risks. It is imperative that the whole dental team are aware of these pitfalls and complications, and appreciate how to minimise and address these.

Bonded orthodontic retention: a practical guide.

Bonded retainers may play an important role in reducing unwanted tooth movements following orthodontic treatment, with an open-ended perspective on retention now established. The importance of planning for bonded retention is emphasised, with key principles in minimising failure rates as well as wire and adhesive options discussed. Approaches to preparation of the wire and the teeth, the bonding process, as well as variations in retainer design, and means of preventing problems and undertaking repairs in order to achieve predictable fixed retention in the long term are also outlined.

Removable orthodontic retainers: practical considerations.

This article provides an overview of removable orthodontic retainers, discussing their history and the different types available, and compares the two most popular removable retainers. Practical information on consent and the clinical steps involved in the provision of removable retainers, as well as suggested wear and care instructions, are also presented.

Orthodontic retention: what's on the horizon?

Orthodontic retention remains one of the great challenges in orthodontics. In this article, we discuss what is on the horizon to help address this challenge, including biological approaches to reduce relapse, treating patients without using retainers, technological developments, personalised medicine and the impact of COVID-19 on approaches to orthodontic retention.

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.

Bonded versus vacuum-formed retainers: a randomized controlled trial. Part 1: stability, retainer survival, and patient satisfaction outcomes after 12 months.

Background: There is a shortage of evidence on the best type of retainer. Objectives: Evaluate upper and lower bonded retainers (BRs) versus upper and lower vacuum-formed retainers (VFRs) over 12 months, in terms of stability, retainer survival, and patient satisfaction. Trial design: Two-arm parallel group multi-centre randomized controlled clinical trial. Methods: Sixty consecutive patients completing fixed appliance therapy and requiring retainers were recruited from 3 hospital departments. They were randomly allocated to either upper and lower labial segment BRs (n = 30) or upper and lower full-arch VFRs (n = 30). Primary outcome was stability. Secondary outcomes were retainer survival and patient satisfaction. A random sequence of treatment allocation was computer-generated and implemented by sealing in sequentially numbered opaque sealed envelopes independently prepared in advance. Patients, operators and outcome could not be blinded due to the nature of the intervention. Results: Thirty patients received BRs (median [Mdn] age 16 years, inter-quartile range [IQR] = 2) and 30 received VFRs (Mdn age 17 years, IQR = 4). Baseline characteristics were similar between groups. At 12 months, there were no statistically significant inter-group differences in post-treatment change of maxillary labial segment alignment (BR = 1.1 mm, IQR = 1.56, VFR = 0.76 mm, IQR = 1.55, P = 0.61); however, there was greater post-treatment change in the mandibular VFR group (BR = 0.77 mm, IQR = 1.46, VFR = 1.69mm, IQR = 2.00, P = 0.008). The difference in maxillary retainer survival rates were statistically non-significant, P = 0.34 (BR = 63.6%, 239.3 days, 95% confidence interval [CI] = 191.1-287.5, VFR = 73.3%, 311.1 days, 95% CI = 278.3-344.29). The mandibular BR had a lower survival rate (P = 0.01) at 12 months (BR = 50%, 239.3 days 95% CI = 191.1-287.5, VFR = 80%, 324.9 days 95% CI = 295.4-354.4). More subjects with VFRs reported discomfort (P = 0.002) and speech difficulties (P = 0.004) but found them easier to clean than those with BRs (P = 0.001). Limitations: Results are after 1 year and we do not know how much the removable retainers were worn. Conclusions: After 1 year, there is no evidence of a significant difference in stability or retainer survival in the maxilla. In the mandible, BRs are more effective at maintaining mandibular labial segment alignment, but have a higher failure rate. In comparison with patients wearing VFRs, patients wearing BRs reported that they caused less interference with speech, required less compliance to wear them, and were more comfortable to wear than VFRs. Patients found the BRs harder to keep clean. Trial registration: The trail was not registered.

Bonded versus vacuum-formed retainers: a randomized controlled trial. Part 2: periodontal health outcomes after 12 months.

Background: Retainer have the potential to compromise periodontal health. Objectives: Evaluate the periodontal health implications of upper and lower bonded retainers (BRs) versus upper and lower vacuum-formed retainers (VFRs) over 12 months. Trial design: Two-arm parallel group multicentre randomized controlled clinical trial. Methods: Sixty consecutive patients completing upper and lower fixed appliance therapy and requiring retainers were recruited from three hospital orthodontic departments. They were randomly allocated to either upper and lower labial segment BRs (n = 30) or upper and lower full-arch VFRs (n = 30). Periodontal health was assessed using the plaque and gingival indices of Silness and Loe, and the calculus index of Greene and Vermillion. Data were collected at debond and placement of the retainers (T0), 3 months (T1), 6 months (T2), and 12 months (T3). A random sequence of treatment allocation was computer-generated and implemented by sealing in sequentially numbered opaque sealed envelopes independently prepared in advance. Patients, operators, and outcome could not be blinded due to the nature of the intervention. Results: Thirty patients received BRs (median age 16 years, interquartile range [IQR] = 2, 50% female, 50% male) and 30 received VFRs (median age 17 years, IQR = 4, 60% female, 40% male). Gingival inflammation decreased from baseline for both types of retainer. There was significantly less plaque and calculus accumulation and better gingival health with VFRs than BRs over the evaluated 12 months. No serious harm was observed. Limitations: It is not known how much the patients chose to wear their removable retainers. The results reported are after 1 year only. Conclusions: After 1 year, BRs were associated with greater accumulation of plaque and calculus than VFRs and minimally worse gingival inflammation than VFRs, but this did not appear to produce any clinically significant, adverse periodontal health problems. Trial registration: This trial was not registered. Funding: There was no funding.

[Retaining corrected skeletal open bites. How can we increase the stability of our results?] / Contenir la correction des béances squelettiques. Comment améliorer la stabilité de nos résultats ?

INTRODUCTION: Retaining corrected skeletal anterior open bites is challenging. If it is possible to identify the aetiological factors causing an open bite, an appropriate choice of treatment and retention may reduce relapse. Extruding anterior teeth to close anterior open bites is known to be unstable, so treatment is typically aimed at controlling the vertical position of maxillary molars, in addition to removing causative factors, such as breaking habits and improving tongue posture. Relapse rates are high, with relapse estimated at about 20-30%, with slightly more stability for a surgical approach. MATERIALS AND METHODS: Various approaches with retainers are described that aim to restrict the eruption of posterior teeth, and improve the position of the tongue. RESULTS: These retainers often require excellent patient compliance and there is a lack of high quality evidence to support their use. Further research is required to confirm the effectiveness of these approaches.

Retention procedures for stabilising tooth position after treatment with orthodontic braces.

BACKGROUND: Retention is the phase of orthodontic treatment that attempts to keep teeth in the corrected positions after treatment with orthodontic braces. Without a phase of retention, there is a tendency for teeth to return to their initial position (relapse). To prevent relapse, almost every person who has orthodontic treatment will require some type of retention. OBJECTIVES: To evaluate the effects of different retention strategies used to stabilise tooth position after orthodontic braces. SEARCH METHODS: We searched the following databases: the Cochrane Oral Health Group's Trials Register (to 26 January 2016), the Cochrane Central Register of Controlled Trials (CENTRAL) (2015, Issue 12), MEDLINE via Ovid (1946 to 26 January 2016) and EMBASE via Ovid (1980 to 26 January 2016). We searched for ongoing trials in the US National Institutes of Health Trials Register (ClinicalTrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform. We applied no language or date restrictions in the searches of the electronic databases. We contacted authors of randomised controlled trials (RCTs) to help identify any unpublished trials. SELECTION CRITERIA: RCTs involving children and adults who had had retainers fitted or adjunctive procedures undertaken to prevent relapse following orthodontic treatment with braces. DATA COLLECTION AND ANALYSIS: Two review authors independently screened eligible studies, assessed the risk of bias in the trials and extracted data. The outcomes of interest were: how well the teeth were stabilised, failure of retainers, adverse effects on oral health and participant satisfaction. We calculated mean differences (MD) with 95% confidence intervals (CI) for continuous data and risk ratios (RR) with 95% CI for dichotomous outcomes. We conducted meta-analyses when studies with similar methodology reported the same outcome. We prioritised reporting of Little's Irregularity Index to measure relapse. MAIN RESULTS: We included 15 studies (1722 participants) in the review. There are also four ongoing studies and four studies await classification. The 15 included studies evaluated four comparisons: removable retainers versus fixed retainers (three studies); different types of fixed retainers (four studies); different types of removable retainers (eight studies); and one study compared a combination of upper thermoplastic and lower bonded versus upper thermoplastic with lower adjunctive procedures versus positioner. Four studies had a low risk of bias, four studies had an unclear risk of bias and seven studies had a high risk of bias. Removable versus fixed retainers Thermoplastic removable retainers provided slightly poorer stability in the lower arch than multistrand fixed retainers: MD (Little's Irregularity Index, 0 mm is stable) 0.6 mm (95% CI 0.17 to 1.03). This was based on one trial with 84 participants that was at high risk of bias; it was low quality evidence. Results on retainer failure were inconsistent. There was evidence of less gingival bleeding with removable retainers: RR 0.53 (95% CI 0.31 to 0.88; one trial, 84 participants, high risk of bias, low quality evidence), but participants found fixed retainers more acceptable to wear, with a mean difference on a visual analogue scale (VAS; 0 to 100; 100 being very satisfied) of -12.84 (95% CI -7.09 to -18.60). Fixed versus fixed retainersThe studies did not report stability, adverse effects or participant satisfaction. It was possible to pool the data on retention failure from three trials that compared polyethylene ribbon bonded retainer versus multistrand retainer in the lower arch with an RR of 1.10 (95% CI 0.77 to 1.57; moderate heterogeneity; three trials, 228 participants, low quality evidence). There was no evidence of a difference in failure rates. It was also possible to pool the data from two trials that compared the same types of upper fixed retainers, with a similar finding: RR 1.25 (95% CI 0.87 to 1.78; low heterogeneity; two trials, 174 participants, low quality evidence). Removable versus removable retainersOne study at low risk of bias comparing upper and lower part-time thermoplastic versus full-time thermoplastic retainer showed no evidence of a difference in relapse (graded moderate quality evidence). Another study, comparing part-time and full-time wear of lower Hawley retainers, found no evidence of any difference in relapse (low quality evidence). Two studies at high risk of bias suggested that stability was better in the lower arch for thermoplastic retainers versus Hawley, and for thermoplastic full-time versus Begg (full-time) (both low quality evidence).In one study, participants wearing Hawley retainers reported more embarrassment more often than participants wearing thermoplastic retainers: RR 2.42 (95% CI 1.30 to 4.49; one trial, 348 participants, high risk of bias, low quality evidence). They also found Hawley retainers harder to wear. There was conflicting evidence about survival rates of Hawley and thermoplastic retainers. Other retainer comparisonsAnother study with a low risk of bias looked at three different approaches to retention for people with crowding, but normal jaw relationships. The study found that there was no evidence of a difference in relapse between the combination of an upper thermoplastic and lower canine to canine bonded retainer and the combination of an upper thermoplastic retainer and lower interproximal stripping, without a lower retainer. Both these approaches are better than using a positioner as a retainer. AUTHORS' CONCLUSIONS: We did not find any evidence that wearing thermoplastic retainers full-time provides greater stability than wearing them part-time, but this was assessed in only a small number of participants.Overall, there is insufficient high quality evidence to make recommendations on retention procedures for stabilising tooth position after treatment with orthodontic braces. Further high quality RCTs are needed.

A multicenter randomized controlled trial to compare a self-ligating bracket with a conventional bracket in a UK population: Part 2: Pain perception.

OBJECTIVE: To compare pain experience between self-ligating and conventional preadjusted edgewise appliance systems with a two-arm parallel trial. MATERIALS AND METHODS: A prospective multicenter randomized controlled clinical trial was conducted in three hospital orthodontic departments. Subjects were randomly allocated to receive treatment with either a self-ligating (3M SmartClip™) or conventional (3M Victory™) bracket system with stratification for operator and center. Standardized protocol was followed for bracket bonding procedure and archwire sequence. Subject pain was recorded using a Verbal Rating Scale to assess discomfort felt on the teeth and soft tissues at the time of the appointment and 1, 3, and 5 days after each archwire change up to the working archwire. Multilevel modeling was used to analyze the data by blinded assessors. RESULTS: One hundred thirty-eight subjects (mean age 14 years 11 months) were enrolled in the study, of which 135 subjects (97.8%) completed the study and 113 (82%) returned the required data regarding pain/discomfort. Perceived pain was statistically higher with the SmartClip™ system compared to the Victory™ system, but this difference was not deemed to be clinically significant. Discomfort was greatest after placement of the initial 0.014-inch nickel-titanium archwire, compared with subsequent wires, and was greatest on day 1, less on day 3, and much less on day 5 after each archwire change. Age and gender did not affect the level of discomfort experienced by subjects undergoing fixed appliance treatment. CONCLUSION: No clinically significant difference in pain experience was found between patients treated with a self-ligating bracket system compared to those treated with a conventional ligation system.