Objective To investigate in 10 orthodontic journals how many randomized controlled trials (RCTs) considered the Hawthorne effect, and if considered, to determine whether it was related to the patients or the therapists involved in the trial and, finally, to discuss the Hawthorne effect in an educational way. Materials and methods A search was performed on the Medline database, via PubMed, for publication type ‘randomized controlled trial’ published for each journal between 1 August 2007 and 31 July 2017. The American Journal of Orthodontics and Dentofacial Orthopedics, Angle Orthodontist, Australian Orthodontic Journal, Dental Press Journal of Orthodontics, European Journal of Orthodontics, Journal of Orthodontics, Journal of Orofacial Orthopedics, Korean Journal of Orthodontics, Orthodontics and Craniofacial Research and Progress in Orthodontics were assessed. Two independent reviewers extracted the data and identified whether the Hawthorne effect was considered or discussed in the articles and whether the Hawthorne effect was related to the behaviour of the patients, the therapists, or both. Results The initial search generated 502 possible trials. After applying the inclusion and exclusion criteria, 290 RCTs were included and assessed. The Hawthorne effect was considered or discussed in 10 of 290 RCTs (3.4%), and all were related to the patients’ and none to the therapists’ behaviour. Conclusions The Hawthorne effect reported in orthodontic RCTs was suboptimal. The researchers’ lack of knowledge about this phenomenon is evident, despite evidence that the Hawthorne effect may cause over-optimistic results or false-positive bias.

Objective: To analyse in 10 orthodontic journals how many randomized controlled trials (RCTs) performed 'single-', 'double-', 'triple-', or 'outcome assessors blinding' and to evaluate, from the number of RCTs that did not conduct blinding, how many could actually have achieved it. Material and methods: Randomized controlled trials published in 10 orthodontic journals between 1 September 2012 and 28 February 2018 were included. A search was performed in PubMed and conducted for publication type 'randomized controlled trial' for each journal. Two reviewers independently analysed each RCT and registered that blinding was performed and included which specific type. It was also evaluated whether misclassifications of blinding items occurred and whether it was possible to achieve blinding among the RCTs that did not perform blinding. Results: After applying the inclusion criteria, 203 RCTs were assessed, and 61.6 per cent of them had used blinding, with the main type being 'outcome assessors blinding' (40.4%) followed by 'single-blinding' (15.3%), 'double-blinding' (2.5%), and 'triple-blinding' (3.4%). In 38.4 per cent of the trials, no blinding was performed; however, 79.4 per cent of them could have achieved blinding. Fifteen RCTs (7.3%) misclassified the blinding in relation to single-, double-, or triple-blinding. Journals followed the CONSORT (AJODO, EJO, JO, OCR) published together significantly more RCTs that performed blinding than journals not following the CONSORT. Conclusions: Blinding of outcome assessors was the most frequent type, as orthodontic trials are often of intervention design and thereby difficult to mask for patients and trial staff. The misclassifications of blinding items may indicate suboptimal knowledge among researchers and peer-reviewers regarding the definitions for diverse blinding types.

AIMS: To identify if lower incisor movements after orthodontic treatment are due to the relapse of the orthodontic treatment or due to natural growth. SUBJECTS AND METHODS: The subjects consisted of 92 patients who have had orthodontic treatment, divided into three groups, group 1: 38 individuals had no retainer in the lower jaw. Group 2: 24 individuals had a retainer 0.028 inch, a spring hard wire bonded to the mandibular canines only. Group 3: 30 individuals had a 0.0195-inch Twist-Flex wire, bonded to all mandibular incisors and canines. Study models before orthodontic treatment (T0), immediately after orthodontic treatment (T1), 6 years after orthodontic treatment (T2), and 12 years after orthodontic treatment (T3) were used for the measurements. The wires in groups 2 and 3 were removed after mean 2.6 years (SD 1.49). Little Irregularity Index (LII), inter-canine distance, available mandibular anterior space, and number of crowded incisors were registered. A Tooth Displacement Index (TDI) was developed to measure the tooth displacement directions at T0 and T3. RESULTS: The LII showed equal values before treatment (T0) and at the follow-up registrations (T2 and T3). But about 25 per cent of the tooth displacements at T2 and T3 did not exist before treatment, at T0. This indicates usual growth changes and not relapse of the orthodontic treatment. CONCLUSION: As about 25 per cent of the displaced incisors can be considered as an effect of natural growth, not a relapse of the orthodontic treatment, it is valuable to use a displacement index in combination with other variables for investigations of stability after orthodontic treatment. Importance of the present study is that it is possible to differ between relapse and usual growth changes.

OBJECTIVES: The aim of this study was to investigate the self-estimated masticatory ability and masticatory performance in patients with dentofacial deformities before and after orthognathic treatment; in comparison to an age- and gender-matched control group. SUBJECTS AND METHODS: The masticatory ability and masticatory performance were evaluated in 121 consecutive patients (treatment group), referred for orthognathic treatment. Eighteen months after treatment, 98 patients (81%) completed a follow-up examination. Masticatory ability was assessed on a visual analog scale, while the masticatory performance was evaluated by a masticatory test using round silicon tablets. Signs and symptoms of temporomandibular disorders (TMD) were registered by a clinical examination and a questionnaire. The control group comprised 56 age- and gender-matched subjects who were examined at baseline. RESULTS: At the baseline examination, the treatment group had a significantly lower masticatory ability and performance compared with the control group. After treatment, the masticatory ability significantly improved in the treatment group and reached the same level as in the control group. The masticatory performance index increased significantly but was still lower than in the control group. Both the masticatory ability and masticatory performance were affected by the number of occlusal contacts during maximal biting pressure and by the self-estimated overall symptoms of TMD. CONCLUSIONS: Patients with dentofacial deformities, corrected by orthognathic treatment, have a significant positive treatment outcome in respect of masticatory ability and masticatory performance. Furthermore, the occlusion and symptoms of TMD have an impact on both masticatory ability and masticatory performance.

Objective To systematically evaluate in five orthodontic journals how many randomized controlled trials (RCTs) use intention to treat (ITT) analysis and to assess the methodological quality of the ITT analysis, and finally, to demonstrate in an academic way how outcomes can be affected when not implementing the ITT analysis. Material and methods A search of the database, Medline, was performed via PubMed for publication type ‘randomized controlled trial’ published for each journal between 1 January 2013 and 30 April 2017. The five orthodontic journals assessed were the American Journal of Orthodontics and Dentofacial Orthopedics, Angle Orthodontics, European Journal of Orthodontics, Journal of Orthodontics, and Orthodontics and Craniofacial Research. Two independent reviewers assessed each RCT to determine whether the trial reported an ITT or not or if a per-protocol analysis was accomplished. Results The initial search generated 137 possible trials. After applying the inclusion and exclusion criteria, 90 RCTs were included and assessed. Seventeen out of 90 RCTs (18.9%) either reported an ITT analysis in the text and/or supported the ITT by flow diagrams or tables. However, six RCTs applied and reported the ITT analysis correctly, while the majority performed a per-protocol analysis instead. Conclusions Nearly all the trials that applied the ITT analysis incorrectly analysed the results using a per-protocol analysis, and thus, overestimating the results and/or having a reduced sample size which then could produce a diminished statistical power.

Background: This article is the result of a debate at the European Journal of Orthodontics Open Session in 2013 in Reykjavik, Iceland. Objective: The aim of this article is to highlight some of the strengths and weakness of clinical orthodontic research, with particular emphasis on randomized controlled trials (RCT). The ultimate aim of improving clinical orthodontic research in general. Design: This article is organized into two sections with arguments for and against RCTs. The backgrounds to evidence-based evaluation and the level or quality of evidence in trials are discussed. The article emphasises what makes high quality clinical research, and gives practical advice including examples of tips and potential pitfalls for those undertaking clinical research. Results and Conclusion: The overriding message is constructive and it is hoped that the article serves as an aid in evaluating, designing, conducting, and reporting clinical research.

Background: Examination with Cone Beam CT (CBCT) is common for localizing maxillary canines with eruption disturbance. The benefits and costs of these examinations are unclear. Objectives: To measure: 1. the proportion of orthodontists' treatment decisions that were different based on intraoral and panoramic radiography (M1) compared with CBCT and panoramic radiography (M2); and 2. the costs of producing different treatment plans, regarding patients with maxillary canines with eruption disturbance. Subjects and methods: Orthodontists participated in a web-based survey and were randomly assigned to denote treatment decisions and the level of confidence in this decision for four patient cases presented with M1 or M2 at two occasions for the same patient case. Results: One hundred and twelve orthodontists made 445 assessments based on M1 and M2, respectively. Twenty-four per cent of the treatment decisions were different depending on which method the raters had access to, whereof one case differed significantly from all other cases. The mean total cost per examination was €99.84 using M1 and €134.37 using M2, resulting in an incremental cost per examination of €34.53 for M2. Limitations: Benefits in terms of number of different treatment decisions must be considered as an intermediate outcome for the effectiveness of a diagnostic method and should be interpreted with caution. Conclusions: For the patient cases presented in this study, most treatment decisions were the same irrespective of radiological method. Accordingly, this study does not support routine use of CBCT regarding patients with maxillary canine with eruption disturbance.

Background: Among child and adolescent patients, persistent but untreated malocclusions may or may not have psychological and social impacts on the individual's quality of life. Objectives: To gain knowledge of malocclusions and its impact on oral health-related quality of life (OHRQOL), we conducted a systematic review of quantitative studies for evidence regarding the influence of malocclusions on OHRQOL in children and adolescents. Materials and methods: Five databases (MEDLINE via PubMed, EMBASE, Psychinfo, CINAHL, and the Cochrane Library) were searched using specified indexing terms. The following inclusion criteria were used: child or adolescent study population; healthy study participants without syndromes such as cleft lip/palate or severe illness; no previous or ongoing orthodontic treatment among participants; a focus on malocclusions and quality of life; controlled or subgrouped according to malocclusions/no malocclusions; malocclusions and/or orthodontic treatment need assessed by professionals using standardized measures; self-assessed OHRQOL estimated using validated questionnaire instruments; full-text articles written in English or Scandinavian languages. Quality of evidence was classified according to GRADE guidelines as high, moderate, or low. Results: The search produced 1142 titles and abstracts. Based on pre-established criteria, the full-text versions of 70 articles were obtained, 22 of which satisfied the inclusion criteria. After data extraction and interpretation, six publications were deemed eligible for full inclusion. All six were of cross-sectional design, and the quality of evidence was high in four cases and moderate in the remaining two. The four studies with a high level of quality reported that anterior malocclusion had a negative impact on OHRQOL, and the two with a moderate level of quality reported that increased orthodontic treatment need had a negative impact on OHRQOL. Conclusion: The scientific evidence was considered strong since four studies with high level of quality reported that malocclusions have negative effects on OHRQOL, predominantly in the dimensions of emotional and social wellbeing.

The aim of this longitudinal study was to compare the prevalence of malocclusion at ages 3 and 7 years in a sample of children, exploring the hypothesis that prevalence of malocclusion is higher at 3 than at 7 years of age and may be influenced by sucking habits. The study sample comprised 386 children (199 girls and 187 boys), aged 3 years at study start, sourced from three Public Dental Service clinics in Sweden. Malocclusion was diagnosed by clinical examination, using a specific protocol. Data on allergy, traumatic injuries, sucking habits, and breathing pattern including nocturnal breathing disturbances were obtained by means of a questionnaire answered by child and parent in conjunction with the initial and final clinical examination. The overall prevalence of malocclusion decreased significantly, from 70 to 58% (P < 0.0001): predominantly anterior open bite, excessive overjet, and Class III malocclusion. Although high rates of spontaneous correction were also noted for deep bite, Class II malocclusion and posterior and anterior crossbites, new cases developed at almost the same rate; thus, the prevalence was unchanged at the end of the observation period. Anterior open bite and posterior crossbite were the only conditions showing significant associations with sucking habits. The results confirm the hypothesis of higher prevalence of malocclusion at 3 years of age and clearly support the strategy of deferring orthodontic correction of malocclusion until the mixed dentition stage.

Background: Scientific evidence is insufficient to answer the question of whether premature birth causes altered tooth-crown dimensions. Objective: To evaluate permanent tooth-crown dimensions in prematurely born children and to compare the findings with full-term born controls. Subjects and Methods: Preterm children of 8-10 years of age were selected from the Swedish Medical Birth Register. One group consisted of 36 extremely preterm children (born before the 29th gestational week); the other group included 37 very preterm children (born during gestational weeks 29-32). The preterm children were compared with 41 matched full-term born children. Clinical examination and study casts were performed on all children. Permanent maxillary and mandibular first molars, central incisors, and laterals were measured with a digital sliding caliper on study casts. The tooth-crowns were measured both mesio-distal and bucco-lingual. Results: Both the mesio-distal and bucco-lingual measurements in the maxillary and mandibular first molars had a significantly smaller width in the extremely preterm group compared with the full-term group. The central incisors and lower laterals were significantly smaller mesio-distally in the extremely preterm group compared to the full-term group. A reduction in tooth size of 4-9% was found between the extremely preterm group and the full-term group for both boys and girls. The maxillary first molars and mandibular left first molar were also smaller mesio-distally in the extremely preterm group compared to the very preterm group. The results indicate that the more preterm the birth, the smaller the tooth-crown dimensions. Independent of gestational age girls had generally smaller teeth than boys. Conclusion: Premature birth is associated with reduced tooth-crown dimensions of permanent incisors and first molars.

The aim of this study was to use a randomized controlled trial methodology to evaluate and compare three different retention methods. The capacity of the retention methods to retain orthodontic treatment results was in this first phase analysed on a short-term basis, i.e. after 1 year of retention. The subjects were recruited from adolescents undergoing fixed appliance treatment at an orthodontic clinic in the National Health Service (NHS) in Sweden between 2001 and 2007. Seventy-five patients (45 girls and 30 boys with a mean age of 14.4 years at the start of retention) were randomized into three retention systems; a vacuum-formed retainer in the maxilla and bonded canine-to-canine retainer in the mandible (group V-CTC), a vacuum-formed retainer in the maxilla combined with stripping of the 10 proximal surfaces of the lower mandibular anterior teeth (group V-S), and a prefabricated positioner covering the teeth in the maxilla and mandible (group P). The main outcome measures were: Little's irregularity index (LII), intercanine and intermolar width, arch length, overjet, and overbite. Registrations were made before orthodontic treatment, when the fixed orthodontic appliance was removed, and after 12 months in retention. Differences in means between groups were tested by one-way analysis of variance. After 1 year of retention, no clinically significant difference in retention capacity was found between the three retention methods. Small but significant differences (P < 0.05) were observed between the V-CTC and V-S groups regarding mandibular canine width, mandibular arch length, and overbite. In group P, two patients failed to co-operate.

SUMMARY BACKGROUND: There are few cost evaluation studies of orthodontic retention treatment. The aim of this study was to compare the costs in a randomized controlled trial of three retention methods during 2 years of retention treatment. MATERIALS/METHODS: To determine which alternative has the lower cost, a cost-minimization analysis (CMA) was undertaken, based on that the outcome of the treatment alternatives was equivalent. The study comprised 75 patients in 3 groups consisting of 25 each. The first group had a vacuum-formed retainer (VFR) in the maxilla and a cuspid retainer in the mandible (group V-CTC), the second group had a VFR in the maxilla combined with stripping of the incisors and cuspids in the mandible (group V-S), and the third group had a prefabricated positioner (group P). Direct cost (premises, staff salaries, material and laboratory costs) and indirect costs (loss of time at school) were calculated. Societal costs were defined as the sum of direct and indirect costs. RESULTS: The societal costs/patient for scheduled appointments for 2 years of retention treatment in group V-CTC were €497, group V-S €451 and group P €420. Societal costs for unscheduled appointments in group V-CTC were €807 and in group V-S €303. In group P, there were no unscheduled appointments. CONCLUSIONS/IMPLICATIONS: After 2 years of retention in compliant patients, the cuspid retainer was the least cost-effective retention appliance. The CMA showed that for a clinically similar result, there were differences in societal costs, but treatment decisions should always be performed on an individual basis.

Objective: Comparison of three different retention strategies 5 years or more postretention. Design, Setting, and Participants: Randomized, prospective, single-centre controlled trial. Forty-nine patients (33 girls and 16 boys) were randomly assigned to one of three retention methods during 2 years by picking a ballot shortly before start of retention treatment. Inclusion criteria were no previous orthodontics, permanent dentition, normal skeletal sagittal, vertical, and transversal relationships, Class I dental relationship, space deficiencies, treatment plan with extractions of four premolars followed by fixed straight-wire appliance. Maxillary and mandibular Little's irregularity index (LII), intercanine and intermolar width, arch length, and overbite/overjet were recorded in a blinded manner, altogether 10 measurements on each patient. Significant differences in means within groups assessed by t-test and between groups by one-way analysis of variance. Interventions: Retention methods: removable vacuum-formed retainer (VFR) covering the palate and the maxillary anterior teeth from canine-to-canine and bonded canine-to-canine retainer in the lower arch (group V-CTC); maxillary VFR combined with stripping of the lower anterior teeth (group V-S); and prefabricated positioner (group P). Results: Maxillary mean LII ranged from 1.8 to 2.6 mm, mean intercanine width 33.6-35.3 mm with a significant difference between groups V-S and P, mean intermolar width 46.8-47.4 mm and mean arch length 21.8-22.8 mm. Mandibular mean LII ranged from 2.0 to 3.4 mm with a significant difference between groups V-S and P, mean intercanine width from 25.4 to 26.6 mm, mean intermolar width from 40.8 to 40.9 mm and mean arch length from 16.9 to 17.3 mm. Mean overbite ranged from 1.8 to 2.7 mm and mean overjet from 3.7 to 4.1 mm. Limitations: A single centre study could be less generalizable. Conclusions: The three retention methods disclosed equally favourable clinical results.

The aim of this trial was to evaluate and compare perceived pain, discomfort, and jaw function impairment between orthodontic treatments combined with skeletal anchorage and treatment using conventional anchorage with headgear or transpalatal bar. A total of 120 adolescent patients in order to start orthodontic treatment were consecutively recruited and randomized into three groups with different anchorage. Group A underwent installation of a skeletal anchorage (Onplant or Orthosystem implant), group B received headgear, and group C a transpalatal bar. Questionnaires were used to assess pain intensity, discomfort, analgesic consumption, and jaw function impairment from baseline to the end of treatment. Pain scores overall peaked on day 2 and were almost back to baseline on day 7. The site with the highest pain scores during treatment was incisors in contact but with no differences between groups. Pain intensity from molars was significantly less in the skeletal anchorage group A compared to the transpalatal bar group C the first 4 days in treatment and with no sign differences compared to headgear. The results confirm that there were very few significant differences between patients’ perceptions of skeletal and conventional anchorage systems during orthodontic treatment. Consequently, these new appliances were well accepted by the patients in a long time perspective and can thus be recommended.

Background Compliance is crucial for the treatment outcome with removable appliances. Previous studies on treatment with the Twin Block appliance have focused on effectiveness in relation to other treatment methods or wear-time. Studies on different check-up intervals to improve compliance seem to be lacking. Objectives To compare the impact of two different check-up prescriptions on patient compliance and treatment outcome during treatment with Twin Block. Trial Design Two-arm parallel group, single-centre, randomized controlled trial. Materials and Methods Seventy-three patients, 38 boys, and 35 girls, mean age 11.2 years, were included and block-randomized into two groups treated with a Twin Block appliance. Group 1 was called for check-up visit every sixth week and group 2 every fourth week. Compliance was evaluated with a TheraMon (R) microsensor, moulded into the appliance, measuring wear-time. Overjet, overbite, and molar relationships were assessed on study casts before and after treatment. The treatment outcomes were analysed on an intention-to-treat basis. Results In group 1, the reduction of overjet was 5.2 mm and the mean wear-time was 6.9 hours. In group 2, the reduction was 4.7 mm and the wear-time was 6.1 hours. Seventy-four per cent of the patients presented an overjet of 4 mm or less. Wear-time did not correlate to age, gender, or severity of malocclusion. Harms No harm was observed in any patient. Lateral open bites were registered during treatment but were normalized at the end of the treatment. Limitations The trial was a single-centre study and long-term effects were not evaluated. Conclusions During treatment with the Twin Block appliance, a 4-week check-up interval did not improve treatment outcome or increase wear-time, compared to a 6-week check-up interval. The mean wear-time was 6.5 hours per day, even if the recommendation was 12 hours.

Background: Serial 3D models can be used to analyze changes, but correct superimposition is crucial before measurements can be assessed. Earlier studies show that every palatal structure changes due to growth or treatment. Here, we describe a new method that uses an algorithm-based analysis to perform superimpositions and measurements in maxillary 3D models. This method can be used to identify deformations. In a second step, only unchanged areas are used for superimposition. Objectives: This study investigates the validity and reliability of this novel method. Methods: Digital 3D models from 16 cases were modified by an independent 3D engineer to simulate space closure and growth. True values for tooth movements were available as reference. Measurements and repeated measurements were performed by four observers. Results: The total tooth movement had an absolute mean error of 0.0225 mm (SD 0.03). The intraclass correlation coefficient (ICC) was 0.9996. Rotational measurements had an absolute mean error of 0.0291 degrees (SD 0.04 degrees) and an ICC of 0.9999. Limitations: Serial models need to be taken with a moderate interval (1 to 2 years). Obvious changed areas in the palate need to be cropped before processing the models. Conclusion: The tested method is valid and reliable with excellent accuracy and precision even when changes through growth or orthodontic treatment occur.

Objective: To analyse cost-effectiveness of anchorage reinforcement with buccal miniscrews and with molar blocks. We hypothesized that anchorage with miniscrews is more cost-effective than anchorage with molar blocks. Trial design: A single-centre, two-arm parallel-group randomized controlled trial. Methods: Adolescents (age 11–19 years) in need of treatment with fixed appliance, premolar extractions, and en masse retraction were recruited from one Public Dental Health specialist centre. The intervention arm received anchorage reinforcement with buccal miniscrews during space closure. The active comparator received anchorage reinforcement with molar blocks during levelling/alignment and space closure. The primary outcome measure was societal costs defined as the sum of direct and indirect costs. Randomization was conducted as simple randomization stratified on gender. The patients, caregivers, and outcome assessors were not blinded. Results: Eighty patients were randomized into two groups. The trial is completed. All patients were included in the intention-to-treat analysis. The median societal costs for the miniscrew group were €4681 and for the molar block group were €3609. The median of the difference was €825 (95% confidence interval (CI) 431–1267). This difference was mainly caused by significantly higher direct costs consisting of material and chair time costs. Differences in chair time costs were related to longer treatment duration. No serious harms were detected, one screw fractured during insertion and three screws were lost during treatment. Generalizability and limitations: The monetary variables are calculated based on a number of local factors and assumptions and cannot necessarily be transferred to other countries. Variables such as chair time, number of appointments, and treatment duration are generalizable. Owing to the study protocol, the benefit of miniscrews as a stable anchorage has not been fully utilized. Conclusions: When only moderate anchorage reinforcement is needed, miniscrews are less cost-effective than molar blocks. The initial hypothesis was rejected. Miniscrews provide better anchorage reinforcement at a higher price. They should be used in cases where anchorage loss cannot be accepted. Trial registration: NCT02644811

BACKGROUND: Malocclusions in adolescents might have a negative impact on oral health-related quality of life (OHRQoL). Potential confounding variables (confounders) such as age, gender, caries, and socioeconomic status may skew the real relationship between malocclusions and OHRQoL.

OBJECTIVES: To analyse the effect of malocclusions in adolescents on OHRQoL, when controlled for potential confounders.

SEARCH METHODS: Five databases (PubMed, Cochrane Library, Cinahl, Scopus, and Web of Science) were searched up to 15 June 2022.

SELECTION CRITERIA: Studies in which OHRQoL in 10-19-year olds with and without malocclusions were compared.

DATA COLLECTION AND ANALYSIS: Screening, data extraction, and quality assessments were performed by four investigators independently. Risk of bias was assessed according to the Swedish Agency for Health Technology Assessment and Assessment of Social Services (SBU) guidelines. To be included, studies had to control for confounders. Certainty of evidence was assessed with GRADE.

RESULTS: Thirteen cross-sectional studies with low and moderate risk of bias were included in the qualitative synthesis. Four of these were also included in the quantitative synthesis (meta-analysis). The 13 studies in the qualitative synthesis displayed a large variation among the indices used for malocclusion ratings, as well as in instruments measuring OHRQoL. There was moderate quality of evidence that malocclusions have a negative effect on OHRQoL. The four articles included in the quantitative synthesis (meta-analysis) measured malocclusions with DAI and OHRQoL with CPQ 11-14 short form. There was moderate quality of evidence that malocclusions have a negative effect on OHRQoL (RR/PR 1.15, 95% CI 1.12-1.18, 3672 participants).

CONCLUSIONS: There is moderate quality of evidence that malocclusions in adolescents have a negative impact on OHRQoL, after taking relevant confounders into consideration. Future studies should ideally use standardized measures for malocclusion ratings and OHRQoL.

REGISTRATION: PROSPERO. CRD42020186152.

Background: Unilateral posterior crossbite is a common malocclusion, and early treatment is recommended to enable normal growth. There are several possibilities regarding choice of appliances used for correcting this malocclusion; however, when treatment is financed by public funds the decision needs to be based not only on the effects but also on the effect in relation to the costs.

Objectives: The aim was to perform a cost-effectiveness analysis comparing quad helix (QH) and rapid maxillary expanders (RME; hyrax-type) in children in the early mixed dentition.

Material and methods: Seventy-two patients were randomized to treatment with either QH or RME, at two different centres. Data were collected from the patient's medical records regarding success rate, number of visits, total treatment time, emergency visits, and so forth, together with answers from patient questionnaires concerning absence from school and use of analgesics. A cost-effectiveness analysis with both an intention-to-treat (ITT) and a per-protocol approach was performed, as well as a deterministic sensitivity analysis.

Results: The success rate, one year after the completion of the expansion, was equal between groups according to the ITT approach. From a healthcare perspective, the mean cost difference between RME and QH was €32.05 in favour of QH (P = 0.583; NS). From a societal perspective, the mean cost difference was €32.61 in favour of QH (P = 0.742; NS). The total appliance cost alone was higher in the RME group €202.67 resp. €155.58 in the QH group (P = 0.001). The probability of RME having a higher cost was 71% from a healthcare perspective and 62.7% from a societal perspective. The total treatment time was 97 days longer in the QH group. In the deterministic sensitivity analysis, when using a higher valuation of the children's educational loss, the QH becomes €58 more costly than the RME. There was a statistically significant difference in chair time and visits between centres (P < 0.001).

Conclusion: The difference in costs between RME and QH is not statistically significant, however, there is a slightly higher probability that RME is more expensive than QH with a mean cost of an additional €32 per patient from a healthcare perspective. Different work procedures at different centres indicate that logistics around the patient's treatment is a more important aspect than appliance used to decrease the number of visits and save chair time and thereby also costs.

BACKGROUND: Mouthwashes containing oral antiseptics or enzymes are suggested suitable for controlling biofilm accumulation in patients with fixed appliances and thereby limiting unwanted side effects during the orthodontic treatment.

OBJECTIVES: To evaluate the effect of an enzyme-based mouthwash on the amount of dental biofilm and the composition of the salivary microbiome in patients undergoing treatment with fixed orthodontic appliances.

TRIAL DESIGN: Randomized double-blind placebo-controlled trial.

MATERIAL AND METHODS: In total, 35 young adolescents (14-18 years) under treatment with fixed appliances were consecutively enrolled and randomly allocated to an experimental or a placebo group by opening a computer-generated numbered envelope. The subjects were instructed to rinse twice daily during an intervention period of 8 days with experimental mouthwash or placebo without active enzymes. Unstimulated whole saliva samples were collected at baseline and after 8 days. The participants and examiner were blinded for the allocation. The primary outcome was the Orthodontic Plaque Index (OPI) and the secondary was the composition of the salivary microbiome.

RESULTS: In total, 28 adolescents (21 females and 7 males) completed the trial and there were no differences in age, clinical, or microbial findings between the test (n = 14) and the placebo group (n = 14) at baseline. We found a decreased OPI in the test group after 8 days and the difference was statistically significant compared with the placebo group (P < 0.05). There were no significant treatment effects on the richness and global composition of the salivary microbiome.

HARMS: In total, one participant in the test group claimed nausea and abandoned the project. In total, two participants did not like the taste of the mouthwash but used it as instructed. No other adverse events or side effects were reported.

LIMITATIONS: Short-term pilot trials may by nature be sensitive for selection and performance biases and are not designed to unveil persisting effects.

CONCLUSION: Daily use of enzyme-containing mouthwash reduced the amount of dental biofilm in adolescents under treatment with the fixed orthodontic appliances, without affecting the composition of the salivary microbiota.

ETHICAL APPROVAL: Approved by the Regional Ethical Board, Lund, Sweden (Dnr 2020-05221).

CLINICAL TRIAL REGISTRATION: NCT05033015.

Background: The clinical benefit of bibloc over monobloc appliances in treating obstructive sleep apnoea (OSA) has not been evaluated in randomized trials. We hypothesized that the two types of appliances are equally effective in treating OSA. Objective: To compare the efficacy of monobloc versus bibloc appliances in a short-term perspective. Patients and methods: In this multicentre, randomized, blinded, controlled, parallel-group equivalence trial, patients with OSA were randomly assigned to use either a bibloc or a monobloc appliance. One-night respiratory polygraphy without respiratory support was performed at baseline, and participants were re-examined with the appliance in place at short-term follow-up. The primary outcome was the change in the apnoea-hypopnea index (AHI). An independent person prepared a randomization list and sealed envelopes. Evaluating dentist and the biomedical analysts who evaluated the polygraphy were blinded to the choice of therapy. Results: Of 302 patients, 146 were randomly assigned to use the bibloc and 156 the monobloc device; 123 and 139 patients, respectively, were analysed as per protocol. The mean changes in AHI were -13.8 (95% confidence interval -16.1 to -11.5) in the bibloc group and -12.5 (-14.8 to -10.3) in the monobloc group. The difference of -1.3 (-4.5 to 1.9) was significant within the equivalence interval (P = 0.011; the greater of the two P values) and was confirmed by the intention-to-treat analysis (P = 0.001). The adverse events were of mild character and were experienced by similar percentages of patients in both groups (39 and 40 per cent for the bibloc and monobloc group, respectively). Limitations: The study shows short-term results with a median time from commencing treatment to the evaluation visit of 56 days and long-term data on efficacy and harm are needed to be fully conclusive. Conclusion: In a short-term perspective, both appliances were equivalent in terms of their positive effects for treating OSA and caused adverse events of similar magnitude. Trial registration: Registered with ClinicalTrials.gov (#NCT02148510).

BACKGROUND AND AIMS: Systematic reviews (SRs) are considered to provide reliable estimates, but flaws in designs, methods of monitoring effects, and outcomes have the potential to bias results. There are several tools for assessing risk of bias (RoB), most of them designed for SRs of beneficial effects. To our knowledge, there is no tool that is adapted specifically to assess RoB in studies of adverse effects associated with orthodontic treatment. To address this, the aim of this study was first to introduce a tool for assessment of RoB in studies of adverse effects associated with orthodontic treatment and, second, to apply it in an SR of external root resorption (ERR) associated with orthodontic treatment with fixed appliance.

MATERIALS AND METHODS: The approach with domains supported by signalling questions was used for the tool. Domains and signalling questions were tailored to the review questions of the SR of studies of ERR after orthodontic treatment using periapical radiography or cone beam computed tomography. Duplicate study selection, data extraction, and RoB assessment using the tool, followed by meta-analyses, were performed.

RESULTS: Using the tool for the assessment of RoB identified shortcomings and report deficiencies of primary studies concerning the presentation of orthodontic treatment, identification of ERR, and analysis of outcomes. RoB assessment resulted in 12 of 32 studies read in full text being included. Reported severe ERR varied across studies between 2 and 14 per cent for all incisors and 10 and 29 per cent for maxillary incisors. Results of ERR related to patients' age and sex, orthodontic diagnosis, and treatment were contradictory. Quality of evidence evaluated by GRADE was low due to study limitations, imprecision, and inconsistency of study results.

CONCLUSIONS: As the tool and its application highlight important issues to consider when planning, conducting, and reporting research, the tool may have a valuable role for quality enhancement of future studies of outcomes of orthodontic treatment. The tool may also serve for authors when planning SRs. Our SR identified a need for studies that use rigorous methodology and transparent reporting.

REGISTRATION: PROSPERO (ID = CRD42018084725).

OBJECTIVES: To compare the costs and treatment effects of headgear activator treatment of Class II malocclusion with excessive overjet between treatments started in the mixed (MD) and late mixed dentition (LMD).

TRIAL DESIGN: Two-arm parallel-group single-centre randomized controlled trial (RCT).

MATERIAL AND METHODS: A total of 56 children presenting Class II malocclusion with excessive overjet were assessed and invited to an RCT designed as intention-to-treat. The children were randomized, by an independent person not involved in the trial into two groups, treatment with headgear activator in the MD starting at the age of 9 or to treatment with a headgear activator in LMD, starting at the age of 11. The primary outcome measure was to compare the treatment costs between the two groups. Societal costs (the sum of direct and indirect costs) were calculated for successful treatments only and when unsuccessful treatments were included. Secondary outcomes were comparisons of oral health-related quality of life (OHRQoL), dental and skeletal treatment effects, lip closure, and trauma incidence. Data collections were performed before and after treatment, corresponding to a treatment period of 2 years. Blinding was accomplished when assessing outcomes.

RESULTS: No group differences in costs were found of successful treatments or when unsuccessful treatments were included. The most pronounced treatment effects in both groups were the reduction of overjet and improved molar relation. Treatment started in MD or in LMD were equal and without significant differences regarding effects on OHRQoL, skeletal effects, lip closure, and incidence of trauma.

HARMS: No harm was observed, but 8 of 30 children (27%) in the MD and 6 of 21 children (29%) in the LMD group showed unsuccessful results.

LIMITATIONS: Costs depend on local factors and can thereby not be directly transferred to other settings. It was a single-centre trial and can thus be less generalizable.

CONCLUSIONS: Regarding costs and treatment effects, there is no difference if headgear activator treatment of excessive overjet starts in the MD or LMD.

CLINICAL TRIAL REGISTRATION: NCT04508322.

OBJECTIVES: To compare early headgear activator treatment of Class II malocclusion with excessive overjet with untreated control subjects in terms of the primary outcomes overjet and overbite as well as the effect regarding oral-health-related quality of life (OHRQoL), lip closure, incidence of trauma, and skeletal changes.

TRIAL DESIGN: Two-arm parallel group single-centre randomized controlled trial.

MATERIAL AND METHODS: A total of 60 children (mean age 9.5 years) presenting a Class II malocclusion with excessive overjet were recruited. The trial was designed as intention-to-treat and the participants randomized by an independent person not involved in the trial to either early treatment with headgear activator or to an untreated control group (UG). Dental and skeletal variables as well as registrations of OHRQoL, lip closure, and incidence of trauma were recorded. For the treatment group, data were registered at baseline before treatment and when treatment was finished, corresponding to approximately 2 years. For the UG, registrations were made at baseline and at 11 years of age. Observers were blinded to treatment allocation when assessing outcomes.

RESULTS: Early treatment with headgear activator significantly decreased overjet and improved molar relationship when compared with untreated controls. The effects were primarily due to dentoalveolar changes. Early treatment had no evident effect regarding OHRQoL, lip closure, or incidence of trauma. Lack of cooperation resulted in unsuccessful treatments for 27% of the patients.

LIMITATIONS: The trial was a single-centre trial and can thus be less generalizable.

CONCLUSIONS: The main treatment effect of early headgear activator treatment of Class II malocclusion with excessive overjet is reduction of overjet.

TRIAL REGISTRATION: NCT04508322.

Objectives: To compare Oral health-related quality of life (OHRQoL) among 9-year-old children with excessive overjet (EO) to children with unilateral posterior crossbite (UPC) and children with normal occlusion (NO). Materials and methods: The study sample sourced from 19 Public Dental Service Clinics in Sweden. Reported are baseline data originating from two controlled trials, one regarding UPC and the other focusing on EO. The NO children derive from the same trials. The UPC group comprised 93 children (45 boys and 48 girls), the EO group 71 children (36 boys and 35 girls), and the NO group 65 children (32 boys and 33 girls). In conjunction to a clinical examination, all children completed the Child Perceptions Questionnaire (CPQ8-10) for evaluation of OHRQoL. The CPQ8-10 comprises 25 questions grouped into four domains: oral symptoms, functional limitations, emotional, and social well-being. Validated questions about pain in the jaws and face were also included. Results: The total mean CPQ score was 5.1 for the UPC, 7.4 for the EO, and 4.4 for the NO group, showing a significant difference between the UPC and EO (P = 0.048) and between EO and NO group (P = 0.012). These differences remained when adjusted for the confounders' caries, trauma, enamel defects, and headache. No difference between UPC and NO was found. The EO children also reported significantly higher scores in the domains emotional and social well-being (P = 0.039 and P = 0.012). Limitations: The study would be strengthened if a longitudinal design had been performed. Conclusion: Children with EO reported significantly lower OHRQoL compared to children with UPC or NO. The children generally reported low CPQ scores that imply an overall fairly good OHRQoL.

AIM: Bone remodelling can be followed through the bone turnover markers (BTMs). Aim of the present study was to record the fluctuation of an osteoclastic and an osteoblastic BTM [C-terminal telopeptide of type I collagen (CTX) and N-terminal pro-peptide of type I pro-collagen (PINP), respectively] in both the gingival crevicular fluid (GCF) and the serum of orthodontic patients before and after the initial application of orthodontic forces.

MATERIALS AND METHODS: Twenty-one Caucasian patients were prospectively evaluated. GCF and blood samples were collected in order to measure the selected biomarkers by ELISA at three time-points: exactly before, 5 days, and 14 days after bonding of the appliances. Standardized sample handling and patient preparation procedures were adopted in order to reduce pre-analytical variability.

RESULTS: GCF and serum CTX levels were found to be independent of age, although higher in the serum of female subjects. PINP levels were found higher in the serum of patients ≥25 years old, as well as in the GCF of males. A positive correlation between serum and GCF baseline PINP levels was observed.

LIMITATIONS: The effect of orthodontic treatment on bone remodelling might not be absolutely representative of the local bone microenvironment as the levels of the specific BTMs where measured within the GCF of the lower front teeth.

CONCLUSIONS: This is the first time PINP and CTX have been evaluated in the GCF and serum of orthodontic patients with fixed appliances. No statistically significant alterations of CTX and PINP levels in the GCF and the serum of patients were recorded over time during the initial stages of orthodontic treatment.

Patients with mandibular prognathism have, for a number of years, been treated by orthognathic surgery and post-surgical changes in the facial profile have been widely reported. However, little is known about the influence of gender and age on the soft tissues. The aim of this study was to investigate changes in the soft tissue profile following orthognathic surgery and to evaluate gender and age differences in the ratios of soft-to-hard tissue change. Forty-two Caucasian adults (18 males and 24 females) aged from 17 to 46 years with mandibular prognathism who underwent vertical ramus osteotomy were included. Lateral cephalograms were taken 2-8 months pre- (T1) and 12-19 months post- (T2) surgically. Five skeletal, two dental, and seven soft tissue parameters were hand traced. Paired and unpaired Student's t-tests, Pearson's correlation coefficients, and multiple regression analyses were used to evaluate the data. Due to the setback of the mandible, soft and hard tissues changed in a 1:1 ratio at the mentolabial fold and chin in females and 1:1,1 in males. Significant differences of soft-to-hard tissue ratios were found at points Pg (P < 0.05) and Gn (P < 0.01). Age effects on the ratios were not significant. Other effects of the mandibular setback on the soft tissue profile were a significant increase in facial convexity, a deepening of the mentolabial fold, an increase in lower lip thickness, and a decrease in upper lip thickness, which increased the nasolabial angle. These findings indicate that use of gender-specific ratios in treatment planning might improve the accuracy of predicting treatment results

Objective: To evaluate whether retention is needed after orthodontic treatment of impacted maxillary canines.

Trial design: Two-arm parallel group single-centre randomized controlled trial.

Materials and methods: Sixty-three patients, 39 girls and 24 boys, were recruited to the study. The inclusion criteria were patients with at least one impacted or unerupted maxillary canine, and moderate irregularity of the maxillary six anterior teeth according to Little’s index (LI). After gaining informed consent from the patient and their custodians, the patients were randomized to one of two groups, i.e. to a non-retention group or a retention group. The randomization process was prepared and carried out by an independent person not involved in the trial and the randomization used blocks of 20 (10 + 10). Primary outcomes were changes in single contact point discrepancy, and LI measured on digitalized three-dimensional study casts 1-year post-treatment. The study casts were anonymized before assessment and the changes were blinded for the assessor. Data were evaluated on an intention-to-treat basis. Thus, all randomized patients were incorporated into the final analysis. In the non-retention group a 10-week interim period was used to detect patients who eventually have a relapse immediately after treatment. If so, the patient got the arch-wire reinserted. Most patients in the retention group received a vacuum-formed retainer and pretreatment spacing cases got a bonded retainer.

Results: Mean irregularity change was 0.4 mm in the retention and 1.3 mm in the non-retention group (P < 0.001). Maximum change was 2.5 mm in the retention and 3.2 mm in the non-retention group (P < 0.001). Most changes in the non-retention group occurred during the 10-week interim period. In the non-retention group, one patient developed contact point discrepancy of >2 mm during the interim period and was realigned.HarmsOne patient met the stopping guideline criteria. This patient had the arch wire reinserted for 2 months. After realignment, the patient received a retention appliance.LimitationsThe trial was a single-centre study and short-term changes were evaluated.

Conclusions: Changes between the retention and the non-retention group were statistically but not clinically significant. Since satisfactory clinical results 1-year post-treatment were found in the non-retention group, retention does not appear to be needed. The 10-week interim period was useful in detecting patients who might have a relapse immediately after treatment.

Trial registration: The trial was not registered.

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

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

Trial design: Three-arm parallel group single-centre randomized controlled trial.

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

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

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

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

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

Trial registration: NCT04616755

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

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

Trial design: Three-arm parallel group single-centre randomized controlled trial.

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

Blinding: The digital casts were blinded for the outcome assessor.

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

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

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

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

Trial registration: www.clinicaltrials.com (NCT04616755).

There are few cost evaluation studies of orthodontic treatment. The aim of this study was to determine the costs of correcting posterior crossbites with Quad Helix (QH) or expansion plates (EPs) and to relate the costs to the effects. To determine which alternative has the lower cost, a cost-minimization analysis was undertaken, based on that the outcome of the treatment alternatives is identical. The study comprised 40 subjects in the mixed dentition, who had undergone treatment for unilateral posterior crossbite: 20 with QH and 20 with EPs. Duration of treatment, number of appointments, broken appointments, and cancellations were registered. Direct costs (for the premises, staff salaries, material and laboratory costs) and indirect costs (loss of income due to parent's assumed absence from work) were calculated and evaluated for successful treatment alone, for successful and unsuccessful treatment and re-treatment when required. The QH had significantly lower direct and indirect costs, with fewer failures requiring re-treatment. Even the costs for successful cases only were significantly lower in the QH than in the EP group. The results clearly show that in terms of cost-minimization, QH is the preferred method for correcting posterior crossbite in the mixed dentition.

BACKGROUND: Initial caries lesion (ICLs) adjacent to orthodontic brackets are the most common side effect of orthodontic treatment with fixed appliances. The reported prevalence is uncertain and varies considerably across studies, from 27% to 97%.

OBJECTIVES: This paper was designed to evaluate and synthesize the available evidence on the prevalence and incidence rates of ICLs in relation to orthodontic treatment. Selection criteria: The review (Prospero protocol CRD42023412952) included randomized and non-randomized clinical trials of interventions, cohort studies, and cross-sectional studies, published after 1990 on the prevalence or incidence of ICLs during or after orthodontic treatment with fixed appliances. Search methods: Pubmed, Scopus, and Embase databases were searched from 1990 until 01 May 2023. The risk of bias assessment was performed with RoB 2 and ROBINS-I tool and the Joanna Briggs Institute Critical Appraisal Checklist. Data collection and analysis: The proportion of individuals with ICLs, reported as the number/percentage of individuals/teeth with ICLs or mean number of ICLs per subject, were used to synthesize results.

RESULTS: The search yielded a total of 468 papers; 21 studies were included in the systematic review, 2 of which were not included in the meta-analysis. The prevalence rate [95%CI] of ICLs was 0.57% [0.48; 0.65] in 1448 patients, 0.22% [0.14; 0.33] in 11583 teeth, with a mean number of lesions equal to 2.24 [1.79; 2.70] in 484 patients evaluated. The incidence rate of new carious lesions developed during orthodontic treatment was 0.48% [0.33; 0.63] in 533 patients, 0.15% [0.08; 0.26] in 1890 teeth with a mean number of ICLs equal to 2.29 [1.12; 3.46] in 208 patients evaluated.

LIMITATIONS: Although the high number of included studies and the overall good quality, there was a significant heterogeneity in the collected data.

CONCLUSION: The prevalence and incidence rates of ICLs in subjects undergoing orthodontic treatment are quite high and raise some concerns in terms of risk assessment of orthodontic treatment. ICLs represent an alarming challenge for both patients and professionals. Effective caries prevention strategies during treatment need to be considered and implemented where appropriate.

SUMMARY There is lack of consensus with respect to the preferred surgical procedure for the treatment of palatally impacted maxillary canines. The aim of this study was to evaluate post-treatment periodontal status of palatally impacted canines treated by open technique with free eruption and closed flap technique and compare it with naturally erupted canines. The subjects comprised 43 patients treated for unilateral palatally impacted maxillary canines and examined 4.19±1.44 months (3–6 months) after removal of the fixed appliance. The group 1 comprised subjects treated by open technique with free eruption (n = 22) and group 2 by closed technique (n = 21). Post-treatment examination comprised periodontal and radiographic examination. There were no significant intergroup differences with respect to periodontal pocket depth or bone support. However, compared with contralateral quadrants with normally erupted canines, quadrants with impacted canines exhibited significant bone loss at the distal contact point of the lateral incisor and the mesial contact point of the canine. The duration of treatment was 28.41±4.96 months for group 1 and 32.19±11.73 months for group 2 (P > 0.05). The mean treatment time required to achieve eruption/extrusion of the impacted canine was 3.05±1.07 months for group 1 and 6.86±4.53 months (P < 0.01) for group 2. It is concluded that choice of surgical method is not associated with any significant differences in post-treatment periodontal status of palatally impacted canines and adjacent teeth.

OBJECTIVES: The objectives of this study were to assess the three-dimensional (3D) treatment changes (palatal surface area and volume) of forced unilateral posterior crossbite correction using either quad-helix or removable expansion plate appliances in the mixed dentition, and to compare the treatment changes with the three-dimensional changes occurring in age-matched untreated unilateral posterior crossbite patients as well as in subjects with normal occlusion and with no or mild orthodontic treatment need. TRIAL DESIGN: Six-arm parallel group multicentre randomized controlled trial. MATERIALS AND METHODS: One-hundred and thirty-five patients with unilateral posterior crossbite with functional shift were recruited. The patients were randomized by an independent person not involved in the trial. The randomization used blocks of 25, and the patients were randomized into the following five groups: quad-helix treatments in specialist orthodontic clinics (QHS), quad-helix treatments in general dentistry (QHG), removable expansion plate treatments in specialist orthodontic clinics (EPS), removable expansion plate treatments in general dentistry (EPG), and untreated crossbite (UC). Twenty-five patients with normal occlusion who served as normal controls were also included in the trial. Blinding of the outcome assessor and data analyst was accomplished. Data on all children were evaluated on an intention-to-treat basis, regarding 3D palatal surface area, palatal projection area, and palatal shell volume; two-dimensional linear measurements were registered at the same time. RESULTS: After treatment, the surface and projection area and shell volume increased in the four treatment groups (QHS, QHG, EPS, and EPG). QHS increased significantly more than EPG for the surface and projection area. The QHS and EPS had significantly higher mean difference for shell volume. LIMITATIONS: The trial considers a short-term evaluation. CONCLUSION: After treatment, there were no significant differences between the four treatment groups and the normal group, which implies that the surface and projection area together with the shell volume for the four treatment groups and the normal group were equivalent. TRIAL REGISTRATION: The trial was registered with https://www.researchweb.org/is/sverige, registration number: 220751.

Background: Economic evaluation is assuming increasing importance as an integral component of health services research. Aim: To conduct a systematic review of the literature and assess the evidence from studies presenting orthodontic treatment outcomes and the related costs. Materials/methods: The literature review was conducted in four steps, according to Goodman’s model, in order to identify all studies evaluating economic aspects of orthodontic interventions. The search covered the databases Medline, Cinahl, Cochrane, Embase, Google Scholar, National Health Service Economic Evaluation Database, and SCOPUS, for the period from 1966 to September 2014. The inclusion criteria were as follows: randomized controlled trials or controlled clinical trials comparing at least two different orthodontic interventions, evaluation of both economic and orthodontic outcomes, and study populations of all ages. The quality of each included study was assessed as limited, moderate, or high. The overall evidence was assessed according to the GRADE system (The Grading of Recommendations Assessment, Development and Evaluation). Results: The applied terms for searches yielded 1838 studies, of which 989 were excluded as duplicates. Application of the inclusion and exclusion criteria identified 26 eligible studies for which the full-text versions were retrieved and scrutinized. At the final analysis, eight studies remained. Three studies were based on cost-effectiveness analyses and the other five on cost-minimization analysis. Two of the cost-minimization studies included a societal perspective, i.e. the sum of direct and indirect costs. The aims of most of the studies varied widely and of studies comparing equivalent treatment methods, few were of sufficiently high study quality. Thus, the literature to date provides an inadequate evidence base for economic aspects of orthodontic treatment. Conclusion: This systematic review disclosed that few orthodontic studies have presented both economic and clinical outcomes.There is currently insufficient evidence available about the health economics of orthodontic interventions. Further investigation is warranted.

Objectives: To evaluate the costs of quad-helix (QH) and removable expansion plate (EP) treatments performed either in specialist or general dentistry for the correction of unilateral posterior crossbite with functional shift in the mixed dentition. Trial design: Four-arm parallel group multicentre randomized controlled trial. Materials and methods: One hundred and ten patients with unilateral posterior crossbite with functional shift were recruited. The patients were randomized by an independent person not involved in the trial. The randomization used blocks of 20 and into the following four groups: QH treatments in specialist orthodontic clinics (QHS), QH treatments in general dentistry (QHG), EP treatments in specialist orthodontic clinics (EPS), and EP treatments in general dentistry (EPG). Blinding was accomplished of the outcome assessor and data analyst. A cost analysis was performed with reference to intention-to-treat (ITT), regarding direct costs, indirect costs, and societal costs (the sum of direct and indirect costs) for calculations of successful treatments alone and for retreatments when required. To determine which alternative has the lower cost, a cost-minimization analysis was undertaken, based on that the outcome of the treatment alternatives were broadly equivalent, so the difference between them reduces to a comparison of costs. Results: In the QHS group, 28 of 28 patients were successfully corrected compared to 23 of 27 in the QHG group. Treatment with expansion plate was less successful: 18 of 27 patients in the EPS group and 18 of 28 in the EPG group. QH treatment performed in specialist orthodontic clinics had significantly lower costs than QH or EP treatment accomplished in general dentistry as well as EP treatments in specialist orthodontic clinics. Limitations: Costs depend on local factors and should not be directly extrapolated to other locations. Conclusion: Treatment of unilateral posterior crossbite in the mixed dentition is recommended to be performed by a specialist orthodontist using the QH appliance. Trial registration: The trial was not registered.

Background/objectives: The management of post-orthodontic white spot lesions is based on remineralization strategies or a minimal-invasive camouflage of the lesions. Aim: The aim of this systematic review was to identify and assess the quality of evidence for the various clinical technologies. Search methods: Four databases were searched for relevant literature published in English between 2011 and October 31 2015 according to a pre-determined PICO. Only controlled clinical studies were considered. Abstract lists and the selected full-text papers were independently examined by two reviewers and any differences were solved in consensus. The Cochrane handbook and the AMSTAR tool were used for grading the risk of bias. The quality of evidence was rated according to GRADE. Results: Out of 280 identified publications, 7 studies on remineralization, micro-abrasion and resin infiltration met the inclusion criteria. Two of them were assessed with low risk of bias. No pooling of results was possible due to study heterogeneity. The quality of evidence for all technologies was graded as very low. Limitations: Only papers published in English with more than 20 adolescents or young adults were considered. Furthermore, a follow-up period of at least 8 weeks was required. The publication bias could not be assessed due to the paucity of included trials. Conclusions/clinical implications: There is a lack of reliable scientific evidence to support re-mineralizing or camouflaging strategies to manage post-orthodontic white spot lesions. Further well-performed controlled clinical trials with long-term follow-up are needed to establish best clinical practice.

Background: Self-applied and professional fluorides are key elements to limit caries-related side-effects during orthodontic treatment with fixed appliances.

Objective: To evaluate the effectiveness of a new fluoride varnish formula containing 1.5% ammonium fluoride in preventing white spot lesions (WSLs) in adolescents undergoing multi-bracket orthodontic treatment.

Subjects and methods: The study employed a randomized controlled triple-blinded design with two parallel arms. One hundred eighty-two healthy adolescents (12-18 years) referred to three orthodontic specialist clinics were eligible and consecutively enrolled. Informed consent was obtained from 166 patients and they were randomly allocated to a test or a placebo group (with aid of a computer program, generating sequence numbers in blocks of 15). In the test group, fluoride varnish was applied in a thin layer around the bracket base every sixth week during the orthodontic treatment, while patients in the placebo group received a varnish without fluoride. The intervention started at onset of the fixed appliances and continued until debonding. The endpoint was prevalence and severity of WSLs on the labial surfaces of the maxillary incisors, canines, and premolars as scored from high-resolution pre- and post-treatment digital photos with aid of a four-level score.

Results: One hundred forty-eight patients completed the trial, 75 in the test group and 73 in the placebo group (dropout rate 10.8%). The total prevalence of WSL's on subject level after debonding was 41.8% in the test group and 43.8% in the placebo group. The number of patients exhibiting more severe lesions (score 3 + 4) was higher in the placebo group (P < 0.05); the absolute risk reduction was 14% and the number needed to treat was 7.1.

Limitations: The multicentre design with somewhat diverging routines at the different clinics may have increased risk for performance bias. No health-economic evaluation was carried out.

Conclusions: Regular applications of an ammonium fluoride varnish reduced the prevalence of advanced WSL during treatment with fixed orthodontic appliances.

Clinical trial registration: ClinicalTrials.gov (NCT03725020).

Protocol: The protocol was not published before trial commencement.

BACKGROUND: Topical fluorides are commonly recommended to prevent the development of white spot lesion (WSL) during treatment with fixed orthodontic appliances (FOAs), but the certainty of evidence is low, and long-term effects of fluoride preventive methods to reduce lesions seem to be rare.

OBJECTIVE: To evaluate the long-term effectiveness of professional applications of a fluoride varnish containing 1.5% ammonium fluoride in preventing WSL development in adolescents undergoing multi-bracket orthodontic treatment.

SUBJECTS AND METHODS: We performed a randomized controlled trial in which 166 healthy adolescents (12-18 years) from three different clinics were enrolled and randomly allocated to a test or a placebo group. The randomization was performed by a computer program, generating sequence numbers in blocks of 15. The fluoride varnish or the non-fluoride placebo varnish was applied in a thin layer around the bracket base every sixth week during the course of the orthodontic treatment (mean duration 1.7 years). We scored the prevalence of WSL on the labial surfaces of the maxillary incisors, canines and premolars immediately after debonding (baseline) and approximately 1 year after debonding, from digital photos with aid of a four-step score. The examiners were not involved in the treatment of the patients and blinded for the group assignment.

RESULTS: One hundred and forty-eight patients were available at debonding and 142 of them could be re-examined after 1 year (71 in the test and 71 in the placebo group). The 1-year attrition rate was 4.0%. On patient level, the prevalence of post-orthodontic WSLs (score ≥ 2) dropped by over 50% during the follow-up with no significant difference between the groups. On surface level, there were significantly fewer remaining WSLs in the test group compared with the placebo group (4.5% versus 10.4%; relative risk 0.44, 95% confidence interval 0.28-0.68).

LIMITATIONS: The compliance with fluoride toothpaste was not checked, and the patients' general dentists may have instigated additional risk-based preventive measures. No cost-benefit analysis was carried out.

CONCLUSIONS: This follow-up study displayed a small beneficial long-term effect of fluoride varnish in reducing WSL development during treatment with FOA.

REGISTRATION: NCT03725020.

PROTOCOL: The protocol was not published before trial commencement.

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

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

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

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

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

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

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

TRIAL REGISTRATION: NCT04616755.

BACKGROUND: Fluoride varnish (FV) is an established technology for primary and secondary caries prevention.

OBJECTIVE: The aim of this review was to evaluate the preventive effect of FV on development of white spot lesions (WSL) when regularly applied during orthodontic treatment with fixed appliances.

SEARCH METHODS: We searched PubMed, Scopus and Google Scholar up to October 2022 using predetermined keywords.

SELECTION CRITERIA: We included randomized controlled trials of a duration of minimum 12 months and at least quarterly FV applications.

DATA COLLECTION AND ANALYSIS: Based on abstracts, we retrieved full-text papers, extracted key outcome data, and assessed risk of bias. Primary outcome was prevalence of WSLs on subject level after debonding. We conducted a narrative synthesis and pooled comparable outcome data in a random effects model.

RESULTS: We included seven studies covering 666 patients and assessed four publications with low or moderate risk of bias and three with high. The prevalence of WSLs at debonding varied between 12 and 55%. All studies presented results in favour for the FV intervention, one reached statistical significance on subject level. Five studies provided data for a meta-analysis. The pooled risk ratio was 0.64 [95% CI: 0.42, 0.98], indicating a statistically significant preventive effect. Certainty of evidence was graded as very low after reducing for risk of bias, inconsistency and imprecision.

LIMITATIONS: We pooled data on subject level and did not consider lesion severity on tooth level.

CONCLUSIONS AND IMPLICATIONS: Even if the certainty of evidence was very low, it was shown that FV can prevent development of WSL when regularly applied during orthodontic treatment. Larger investigations reporting a core outcome set are required to increase the certainty of evidence.

REGISTRATION: PROSPERO database (CRD42022370062).

OBJECTIVE: To evaluate the effectiveness of daily tooth brushing with high-fluoride toothpaste on white spot lesion (WSL) formation in adolescents during treatment with fixed orthodontic appliances (FOA). Materials and Methods: Four hundred and twenty-four healthy 11- to 16-year-old patients, referred to five Orthodontic Specialist Clinics, were randomized to use either toothpaste containing 5000 ppm fluoride or regular toothpaste with 1450 ppm fluoride. To be eligible for inclusion, the patients had to be scheduled for bimaxillary treatment with FOA for an expected duration of at least 1 year. The primary and secondary outcome measures were prevalence and incidence of WSL, as registered from digital photos of the maxillary incisors, canines, and premolars taken before onset and immediately after debonding. The photos were evaluated separately by two blinded and calibrated clinicians using a 4-step score. A random sample of 50 cases was reassessed to check intra- and interexaminer reliability (Kappa = 0.70; 0.74). Results : The use of high-fluoride toothpaste resulted in fewer WSL (P = 0.042) with a prevented fraction of 32%. The lateral incisor was most commonly affected in both groups. Conclusion: To prevent WSL during treatment of FOA, daily use of high-fluoride toothpaste may be recommended.

Dentoalveolar changes in adulthood have not been extensively documented. Such changes may have important implications for the long-term stability of orthodontic treatment. To analyse occlusal and dentoalveolar changes in adults from the age of 20 years to the age of 60 years. The material comprised 18 Swedish dentists, 16 men and 2 women, with no missing teeth and no prosthodontic or orthodontic treatment. Measurements were recorded on study casts made between 1949 and 1989 at the Department of Stomatognathic Physiology at the Faculty of Odontology in Malmö, thus documenting changes over an average period of 38.4 years. Malocclusion traits, overbite, overjet, dental arch length and width, and Little’s irregularity index were registered. There was a significant increase in Little’s irregularity index in the mandible (1.0 mm, P < 0.01) and a decrease in arch length in both jaws (0.5–0.9 mm, P < 0.05). The maxillary and mandibular intercanine widths decreased by 0.8 and 1.0 mm, respectively (P < 0.001). The malocclusion traits, overbite, and overjet remained unchanged during the observation period. The results confirm that dentoalveolar changes occur as a continuous process throughout adult life. The findings of potential clinical importance are decreases in arch length and depth, resulting in a decrease in intercanine width and an increase in anterior crowding. In clinical orthodontic practice, these findings have important implications for treatment planning and long-term stability after orthodontic treatment.

Objective: To compare the effectiveness of fixed and removable orthodontic appliances in correcting anterior crossbite with functional shift in the mixed dentition. Subjects and methods: Consecutive recruitment of 64 patients who met the following inclusion criteria: early to late mixed dentition, anterior crossbite with functional shift, moderate space deficiency in the maxilla, i.e. up to 4mm, a non-extraction treatment plan, the ANB angle > 0 degree, and no previous orthodontic treatment. Sixty-two patients agreed to participate. The study was designed as a randomized controlled trial with two parallel arms. After written consent was obtained, the patients were randomized, in blocks of 10, for treatment either with a removable appliance with protruding springs or a fixed appliance with multi-brackets. The main outcome measures assessed were success rate, duration of treatment, and changes in overjet, overbite, and arch length. The results were also analysed on an intention-to-treat basis. Results: The crossbite was successfully corrected in all patients in the fixed appliance group and all except one in the removable appliance group. The average duration of treatment was significantly less, 1.4 months, for the fixed appliance group (P < 0.05). There were significant increases in arch length and overjet in both treatment groups, but significantly more in the fixed appliance group (P < 0.05 and P < 0.01).  Conclusion: Anterior crossbite with functional shift in the mixed dentition can be successfully corrected by either fixed or removable appliance therapy in a short-term perspective.

OBJECTIVE: Economic evaluations provide an important basis for allocation of resources and health services planning. The aim of this study was to evaluate and compare the costs of correcting anterior crossbite with functional shift, using fixed or removable appliances (FA or RA) and to relate the costs to the effects, using cost-minimization analysis. DESIGN, SETTING, AND PARTICIPANTS: Sixty-two patients with anterior crossbite and functional shift were randomized in blocks of 10. Thirty-one patients were randomized to be treated with brackets and arch wire (FA) and 31 with an acrylic plate (RA). Duration of treatment and number and estimated length of appointments and cancellations were registered. Direct costs (premises, staff salaries, material, and laboratory costs) and indirect costs (the accompanying parents' loss of income while absent from work) were calculated and evaluated with reference to successful outcome alone, to successful and unsuccessful outcomes and to re-treatment when required. Societal costs were defined as the sum of direct and indirect costs. INTERVENTIONS: Treatment with FA or RA. RESULTS: There were no significant differences between FA and RA with respect to direct costs for treatment time, but both indirect costs and direct costs for material were significantly lower for FA. The total societal costs were lower for FA than for RA. LIMITATIONS: Costs depend on local factors and should not be directly extrapolated to other locations. CONCLUSION: The analysis disclosed significant economic benefits for FA over RA. Even when only successful outcomes were assessed, treatment with RA was more expensive. TRIAL REGISTRATION: This trial was not registered. PROTOCOL: The protocol was not published before trial commencement.