Spontaneous space closure in patients treated with early extraction of the first permanent molar: a retrospective cohort study using radiographs

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.

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

BACKGROUND

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

OBJECTIVE

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

TRIAL DESIGN

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

METHODS

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

BLINDING

The digital casts were blinded for the outcome assessor.

RESULTS

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

HARMS

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

LIMITATIONS

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

CONCLUSIONS

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

TRIAL REGISTRATION

www.clinicaltrials.com (NCT04616755).

Effects of premolar extraction and orthodontic treatment in adolescents - a retrospective cephalometric study

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.

Prevention of white spot lesions with fluoride varnish during orthodontic treatment with fixed appliances: a systematic review

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).

Malocclusions and quality of life among adolescents: a systematic review and meta-analysis

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.

Effect of an enzyme-containing mouthwash on the dental biofilm and salivary microbiome in patients with fixed orthodontic appliances: a randomized placebo-controlled pilot trial

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.

Patient compliance with Twin Block appliance during treatment of Class II malocclusion: a randomized controlled trial on two check-up prescriptions

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® 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.

CLINICAL TRIAL REGISTRATION

NCT05155774.

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

Background

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

Objective

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

Trial design

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

Materials and methods

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

Results

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

Limitations

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

Conclusions

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

Trial registration

NCT04616755.

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

BACKGROUND

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

OBJECTIVE

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

TRIAL DESIGN

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

MATERIALS AND METHODS

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

RESULTS

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

HARMS

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

LIMITATIONS

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

CONCLUSIONS

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

TRIAL REGISTRATION

NCT04616755.

Comparison of post-treatment changes with and without retention in adolescents treated for maxillary impacted canines-a randomized controlled trial

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.

Harms

One patient met the stopping guideline criteria. This patient had the arch wire reinserted for 2 months. After realignment, the patient received a retention appliance.

Limitations

The 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.

Orthodontic appliances and MR image artefacts: An exploratory in vitro and in vivo study using 1.5-T and 3-T scanners

Purpose

The aim of this study was to assess the artefacts of 12 fixed orthodontic appliances in magnetic resonance images obtained using 1.5-T and 3-T scanners, and to evaluate different imaging sequences designed to suppress metal artefacts.

Materials and Methods

In vitro, study casts of 1 adult with normal occlusion were used. Twelve orthodontic appliances were attached to the study casts and scanned. Turbo spin echo (TSE), TSE with high readout bandwidth, and TSE with view angle tilting and slice encoding for metal artefact correction were used to suppress metal artefacts. Artefacts were measured. In vivo, 6 appliances were scanned: 1) conventional stainless-steel brackets; 2) nickel-free brackets; 3) titanium brackets; 4) a Herbst appliance; 5) a fixed retainer; and 6) a rapid maxillary expander. The maxilla, mandible, nasopharynx, tongue, temporomandibular joints, and cranial base/eye globes were assessed. Scores of 0, 1, 2, and 3 indicated no artefacts and minor, moderate, and major artefacts, respectively.

Results

In vitro, titanium brackets and the fixed retainer created minor artefacts. In vivo, titanium brackets caused minor artefacts. Conventional stainless-steel and nickel free brackets, the fixed retainer, and the rapid maxillary expander caused major artefacts in the maxilla and mandible. Conventional stainless-steel and nickel-free brackets caused major artefacts in the eye globe (3-T). TSE with high readout bandwidth reduced image artefacts in both scanners.

Conclusion

Titanium brackets, the Herbst appliance, and the fixed retainer caused minor artefacts in images of neurocranial structures (1.5-T and 3-T) when using TSE with high readout bandwidth.

Fluoride varnish for white spot lesion prevention during orthodontic treatment: results of a randomized controlled trial 1 year after debonding

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.

Fluoride varnish for the prevention of white spot lesions during orthodontic treatment with fixed appliances: a randomized controlled trial

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 &lt; 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.

Do fixed orthodontic appliances cause halitosis? A systematic review

Objective

To examine: (I) the current evidence of the impact of fixed orthodontic appliances on the development of halitosis in patients undergoing orthodontic treatment, and (II) the influence of different orthodontic bracket systems on halitosis.

Material and methods

Three electronic databases (PubMed, Scopus, and Cochrane Library) were searched prior to March 15, 2018. The review was systematically conducted and reported according to the Cochrane Handbook and the PRISMA statement. Only Randomised Clinical Trials (RCTs) were considered. Selected full-text papers were independently assessed by four investigators and any disagreements were resolved by consensus. The Cochrane Handbook was used to grade the risk of bias and the quality of evidence was rated according to GRADE.

Results

Out of 363 identified studies, three RCTs on halitosis and fixed orthodontic appliances met the inclusion criteria. The risk of bias in the three studies was rated as high and the quality of evidence was rated as very low.

Conclusions/clinical implications

There is a lack of scientific evidence that subjects with fixed orthodontic appliances develop halitosis during treatment. Additional well-conducted RCTs with extended periods of assessment are needed as well as consensus concerning cut-off values for the diagnosis of halitosis.

Management of post-orthodontic white spot lesions: an updated systematic review

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 31 October 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, seven 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.

Efficacy of low-level laser therapy in accelerating tooth movement, preventing relapse and managing acute pain during orthodontic treatment in humans: a systematic review

BACKGROUND

Recently low-level laser therapy (LLLT) has been proposed to improve orthodontic treatment. The aims of this systematic review were to investigate the scientific evidence to support applications of LLLT: (a) to accelerate tooth movement, (b) to prevent orthodontic relapse and (c) to modulate acute pain, during treatment with fixed appliances in children and young adults.

METHODS

To ensure a systematic literature approach, this systematic review was conducted to Goodman's four step model. Three databases were searched (Medline, Cochrane Controlled Clinical Trials Register and Scitation), using predetermined search terms. The quality of evidence was rated according to the GRADE system.

RESULTS

The search identified 244 articles, 16 of which fulfilled the inclusion criteria: three on acceleration of tooth movement by LLLT and 13 on LLLT modulation of acute pain. No study on LLLT for prevention of relapse was identified. The selected studies reported promising results for LLLT; elevated acceleration of tooth movement and lower pain scores, than controls. With respect to method, there were wide variations in type of laser techniques.

CONCLUSIONS

The quality of evidence supporting LLLT to accelerate orthodontic tooth movement is very low and low with respect to modulate acute pain. No studies met the inclusion criteria for evaluating LLLT to limit relapse. The results highlight the need for high quality research, with consistency in study design, to determine whether LLLT can enhance fixed appliance treatment in children and young adults.

On minor salivary gland secretion in children, adolescents and adults

The minor salivary glands are of great importance for maintenance of homeostasis in the oral cavity. These glands continuously secrete substances which lubricate and protect the oral tissues, contributing to comfort and health. The minor salivary glands contribute approximately 7-8 per cent of the total volume of saliva. Flow rate and composition seem to vary according to anatomical location. Current knowledge about the minor salivary glands is derived primarily from studies on adults. The overall aim of this thesis was to study age-related changes in minor gland saliva, from childhood to adulthood. By increasing the knowledge of minor gland secretion, we hopefully better understand how different mucosal locations are lubricated and protected in individuals of different ages and various health statuses. The project comprises four papers. In Paper I, the flow rate and numerical density of the labial and buccal minor glands of pre-school children, adolescents and adults were investigated. Saliva was collected on filter paper discs and the flow rate was measured by the Periotron-method. The numerical density was assessed by PAS-staining.

KEY FINDINGS

The flow rate of the buccal glands was significantly lower in children than in adults and the number of labial glands was significantly higher in children than in the other age-groups. In Paper II, the composition of minor gland saliva of the three age groups (Paper I) was analysed (by ELISA-technique), with reference to the mucins MUC5B and MUC7, representing some of the major components of innate salivary immunity.

KEY FINDINGS

Children did not differ from adolescents and adults with respect to MUC5B content in labial gland saliva, but had less MUC7 than the adults. In the buccal gland saliva, detectable amounts of the mucins were found in only a few of the participants. In Paper III, the content of the adaptive immune component (salivary IgA) in minor gland saliva of pre-school children, adolescents and adults was measured by the ELISA technique. The salivary IgA-concentration in whole saliva of the three age-groups was also estimated.

KEY FINDINGS

The IgA-concentration was significantly lower in the labial glands and the whole saliva of the children than in the adults. In Paper IV, age-dependent differences of other innate components were studied in pre-school children, adolescents and adults, by analysing the amount of glycoprotein 340 (gp-340) in minor gland and whole saliva, using the ELISA technique. The content of sialic acid, a common terminal structure of glycoproteins, was analysed using the ELLA technique.

KEY FINDINGS

With respect to minor gland saliva, no differences were disclosed among pre-school children, adolescents and adults. However, the gp-340 content of whole saliva was significantly higher in the children than in the adults. The above investigations of properties of minor salivary glands in children, adolescents and adults seems to be the first to present data on age-dependent variations in gland density and secretions from healthy individuals. The results show high gland density, mature innate immunity and an ongoing maturation of adaptive immunity in the saliva of children. The report provides a reference for further comparative studies on minor gland saliva of younger individuals in health and disease.

Minor salivary gland secretion in children and adults

The minor salivary glands are of great importance in the physiology and pathology of the oral cavity. So far, studies of the minor glands have concentrated on adults. In the present study, minor salivary gland secretion was studied in the buccal and labial mucosa of 3-year-old children, adolescents and young adults. In addition, the number of glands per surface area was assessed in the labial mucosa. A total of 90 individuals were included, 30 in each age-group. Saliva was collected on filter paper discs and the salivary secretion rate was measured using a Periotron 8000. The number of secreting labial glands was assessed on PAS-stained filter paper discs under a microscope. Salivary secretion in the buccal mucosa was found to be age-related, with a statistically significant lower rate of secretion (P=0.003) in the 3-year-olds (mean 7.7 microl x cm(-2) x min(-1)) compared with the young adults (11.9 microl x cm(-2) x min(-1)). No significant differences between the sexes were noted. For the labial glands, no age- or sex-related differences were found. In all age-groups, salivary secretion was significantly higher in the buccal than in the labial mucosal area. A statistically significant difference in number of secreting glands was found between all age-groups, with a decreasing number of glands per surface unit with age. The number of glands was significantly lower in males compared with females in the group of adults. The lower rate of buccal salivary secretion in the young children may imply that the oral mucosa is more vulnerable to external injury and that caries protection on the buccal molar surfaces is lower. Previous studies indicate that adults with a reduced rate of minor salivary gland secretion are more susceptible to caries.

Long-term exposure to enhanced ultraviolet-B radiation in the sub-arctic does not cause oxidative stress in Vaccinium myrtillus

The aim of this work was to assess whether or not oxidative stress had developed in a dwarf shrub bilberry (Vaccinium myrtillus L.) under long-term exposure to enhanced levels of ultraviolet-B (u.v.-B) radiation. The bilberry plants were exposed to increased u.v.-B representing a 15% stratospheric ozone depletion for seven full growing seasons (1991-1997) at Abisko, Swedish Lapland (68°N). The oxidative stress was assessed on leaves and stems by analysing ascorbate and glutathione concentrations, and activities of the closely related enzymes ascorbate peroxidase (EC 1.11.1.11) and glutathione reductase (EC 1.6.4.2). The affects of autumnal leaf senescence and stem cold hardening on these variables were also considered. The results showed that the treatment caused scarcely any response in the studied variables, indicating that u.v.-B flux representing a 15% ozone depletion under clear sky conditions is not sufficient to cause oxidative stress in the bilberry. It is suggested that no strain was evoked since adaptation was possible under such u.v.-B increases. The studied variables did, however, respond significantly to leaf senescence and especially to stem cold hardening.