Objectives: To evaluate the cephalometric effects of premolar extraction on skeletal and dental parameters, and on the soft tissues, in patients subsequently treated with fixed appliances. Prevalence and severity of external apical root resorption due to premolar extraction were also examined.Materials and methods: The dental records of 79 patients treated with fixed appliances were retrieved (groups: extraction, n = 19; non-extraction, n = 60). Pre- and post-treatment statuses of skeletal, dentoalveolar, and soft tissue variables were analyzed on lateral cephalograms to determine change. Periapical radiographs of the maxillary incisors were assessed for external apical root resorption using the Levander & Malmgren index. The t-test, Mann-Whitney U test, chi-squared test, and Kruskal-Wallis test were used to analyze the data. Significance was set at p < .05.Results: Changes in the protrusion and proclination of the incisors and in lip position were significantly different between the groups. Prevalence of external apical root resorption in the two groups was similar.Conclusions: Our findings suggest that extraction therapy affects dentoalveolar traits but not jaw position, nor the risk of root resorption, in patients treated with fixed appliances

OBJECTIVES: To assess the success rate of spontaneous space closure after extraction of the first permanent molar (FPM) in the maxilla and the mandible, and to identify the factors that make spontaneous space closure most favorable in each.

MATERIALS AND METHODS: A retrospective records-based cohort study was conducted through a search of the database of the Public Dental Service, Stockholm County Council, Stockholm, for young adults born between 2000 and 2001, who underwent extraction of one or more FPM between 2006 and 2016. A total of 995 extracted teeth were identified, of which 203 teeth in 155 patients met the inclusion criteria.

RESULTS: Of the 203 extracted teeth, 166 (81.8%) did not receive any orthodontic treatment. The success rate for space closure in orthodontically treated patients was 91.9%. The success rate for spontaneous space closure was 84.3%. All unsuccessful spontaneous space closure in the maxilla occurred in patients older than 12 years. The dental developmental stage of the second permanent molar (SPM) had a statistically significant association with spontaneous space closure in the mandible (P < .001).

CONCLUSIONS: The success rate of spontaneous space closure was high (84.3%) and was higher in the maxilla (94.1%) than the mandible (74.1%). Age at time of extraction and dental developmental stage of the SPM were significant factors for successful spontaneous space closure in the maxilla and mandible, respectively.

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: 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 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: 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).

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).

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.

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: 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.