Third molar agenesis in individuals with supernumerary teeth.

OBJECTIVES: To explore the association between third molar agenesis and supernumerary tooth formation in a white-European population. MATERIALS AND METHODS: A record review in various orthodontic clinics identified 380 eligible white-European individuals, half of whom had non-syndromic permanent supernumerary teeth (122 males and 68 females, totalling 244 supernumerary teeth; median age: 13.1, iqr: 1.5 years), and the other half were age- and sex-matched controls with full dentition, excluding the third molars. Tooth sequences were identified in panoramic radiographs. RESULTS: In the supernumerary group, approximately 80% of the individuals had a single supernumerary tooth, followed by those having two additional teeth. In both groups, there was no sexual dimorphism in third molar agenesis severity. The prevalence of third molar agenesis in the supernumerary group was similar to that of the control group (28/190 = 14.7% in both groups; p = 1.0). In total, 53 third molars were missing in the supernumerary group (n = 190) compared to 67 in the control group (n = 190; p = .862). The ratio of bilateral to unilateral third molar agenesis was significantly lower in the supernumerary group than in the control group (1.0 vs. 3.7, respectively; p = .026). CONCLUSION: The presence of supernumerary teeth did not significantly alter the likelihood of third molar agenesis or its severity. Bilateral third molar agenesis was considerably less prevalent in individuals with supernumerary teeth compared to controls. The present novel findings have important clinical and developmental implications.

Comparing the accuracy of 3 different liquid crystal display printers for dental model printing.

INTRODUCTION: This study aimed to evaluate the accuracy in terms of trueness and precision of 3 different liquid crystal display (LCD) printers with different cost levels. METHODS: Three LCD 3-dimensional (3D) printers were categorized into tiers 1-3 on the basis of cost level. The printers' accuracies were assessed in terms of trueness and precision. For this research, 10 standard tessellation language (STL) reference files were used. For trueness, each STL file was printed once with each 3D printer. For precision, 1 randomly chosen STL file was printed 10 times with each 3D printer. After that, a model scanner was used to scan the models, and STL comparisons were performed using reverse engineering software. For the measurements regarding trueness and precision, the Friedman test was used. RESULTS: There were significant differences among the 3 printers (P <0.05). The trueness and precision error were lower in models printed with a tier-1 printer than in the remaining 3D printers (P <0.05). The tier-2 and -3 printers presented very similar performance. CONCLUSIONS: LCD 3D printers can be accurately used in orthodontics for model printing depending on the specific orthodontic use. The cost of a printer is relevant to the results only for the higher expense of the 3D printer in this study.

Comparing CBCT to model scanner for dental model scanning. An in vitro imaging accuracy study.

OBJECTIVE: The aim of this study is to compare the accuracy of cone beam computed tomography (CBCT) for dental model scanning to the accuracy of model scanners. METHODS: Subjects from private practice were collected and scanned according to specific selection criteria. A total of 10 STL files were produced and used as reference files. They were printed with a three-dimensional (3D) printer and then scanned with CBCT and model scanner. For trueness evaluation, all models were scanned once with both equipments. Each file derived from each scan was compared with the corresponding reference model file. For the precision measurements, the physical model from the first master reference model file was scanned 10 times with each equipment and compared with the reference STL file. A reverse engineering software was used for all 3D best-fit comparisons. RESULTS: With regard to the measurement of trueness of each method, the calculated mean root mean square (RMS) value was 0.06±0.01mm for the CBCT, and 0.15±0.02mm for the model scanner. There was a significant difference between the two methods (P<0.01). For the evaluation of precision of each scanner, the mean RMS value was 0.0056±0.001mm for the CBCT, and 0.153±0.002mm for model scanner. There was a significant difference between the two methods (P<0.01). CONCLUSIONS: Cone Beam Computed Tomography seems to be an accurate method for scanning dental models. CBCT performs better than model scanners to scan dental models in terms of trueness and precision.

Supernumerary Tooth Patterns in Non-Syndromic White European Subjects.

Supernumerary teeth form at an incidence of about 3% in the population, with differences among races and various clinical consequences. Information on detailed patterns, and especially on white subjects, is scarce in the literature. Therefore, we aimed to investigate the patterns of non-syndromic permanent supernumerary teeth in a white European population. A record review was performed in different orthodontic clinics and identified 207 eligible individuals with 258 supernumerary teeth. Approximately 80% of the subjects had one supernumerary tooth, while 15% had two. Supernumerary tooth formation was more often evident in males (male/female: 1.65). However, there was no sexual dimorphism in its severity. The following pattern sequences, with decreasing prevalence order, were observed in the maxilla: 21 > 11 > 12 > 18 > 28 and in the mandible: 34 > 44 > 35 > 45 > 42. Supernumerary teeth were most often unilaterally present, without sexual dimorphism. In the maxilla, they were more often anteriorly present, whereas in the mandible, an opposite tendency was observed. Supernumerary teeth were consistently more often observed in the maxilla than in the mandible; 74% were impacted, 80% had normal orientation (13% horizontal, 7% inverted), and 53% had normal size. The present thorough supernumerary tooth pattern assessment enables a better understanding of this condition with clinical, developmental, and evolutionary implications.

Long-term effectiveness of non-surgical open-bite treatment: a systematic review and meta-analysis.

BACKGROUND: The etiology of open bite is complex, involving various genetic or environmental factors. Several treatment alternatives have been suggested for the correction of open bite, yet their long-term effectiveness remains controversial. OBJECTIVE: To assess the long-term effectiveness of open-bite treatment in treated with non-surgical approaches versus untreated patients, through lateral cephalometric radiographs. SEARCH METHODS: Unrestricted search of 16 electronic databases and manual searches up to November 2022. SELECTION CRITERIA: Randomized or non-randomized controlled trials reporting on the long-term effects of open-bite treatment through angular lateral cephalometric variables. DATA COLLECTION AND ANALYSIS: Only angular variables on lateral cephalometric radiographs were considered as primary outcomes. For each outcome, the mean differences and 95% confidence intervals were calculated using the random-effects model to consider existing heterogeneity. The revised Cochrane risk-of-bias tool (R.o.B. 2.0) and the risk-of-bias tool for non-randomized studies for interventions (ROBINS-I) were utilized for the randomized and non-randomized trials, respectively. RESULTS: From the initially identified 26,527 hits, only 6 studies (1 randomized and 5 retrospective controlled trials) were finally included in this systematic review reporting on 244 open-bite individuals (134 patients and 110 untreated controls), while five of them were included in the meta-analyses, assessing either the interval ranging from treatment start to post-retention (T3-T1) or from end of treatment to post-retention period (T3-T2). Regarding the vertical plane, for the T3-T2 interval, no significant differences were found for the assessed skeletal measurements, indicating a relative stability of the treatment results. Similarly, with regard to the T3-T1 interval, no significant differences could be identified for the examined skeletal variables, implying that the produced effects are rather minimal and that the correction of the open bite was performed mainly through dentoalveolar rather than skeletal changes. Further, no significant changes could be identified regarding the inclination of the upper and lower incisors. Only the nasolabial angle was significantly reduced in the treated patients in the long term. CONCLUSIONS: According to existing evidence, the influence of non-surgical treatment of open bite on the skeletal tissues and the inclination of the incisors is rather minimal in the long term, while only the nasolabial angle was significantly reduced.

Three-Dimensional Cone-Beam Computed Tomography Evaluation of Changes in Naso-Maxillary Complex Associated with Rapid Palatal Expansion.

The introduction of Cone-Beam Computed Tomography (CBCT) in orthodontics has added a new tool to diagnosis and treatment planning. The aim of this prospective clinical trial was to investigate the changes in the dimensions of the naso-maxillary complex in growing patients after RPE using CBCT. A total of 16 growing children (8 females, 6 males) with a mean age of 11, 12 ± 1 and 86 years underwent RPE as part of their comprehensive orthodontic treatment. CBCT scans were obtained before RPE (T1), immediately after RPE (T2) and 6 months after RPE (T3). The dimensions of the nasal width, nasal floor and the aperture of the midpalatal suture were calculated in different coronal slices of CBCT. Evaluation of the mean value variance per measurement at the three time intervals were performed using the paired Wilcoxon signed-rank test. Differences between the three time intervals were assessed by performing Multiple Pairwise Comparisons. A statistically significant increase in all measurements was seen immediately after RPE expansion (T2-T1) and six months after expansion (T3-T1). Between the end of expansion and 6 months in retention (T3-T2), a decrease was observed for all measurements. RPE can cause expansion of the nasal cavity in growing patients. The expansion of the midpalatal suture follows a triangular pattern of opening.

Assessment of the reliability of measurements taken on digital orthodontic models obtained from scans of plaster models in laboratory scanners. A systematic review and meta-analysis.

BACKGROUND: In recent years, digital models have become increasingly popular among orthodontists, both for clinical and scientific purposes. It is, therefore, crucial to appropriately investigate their reliability. To this date, however, there has been no scientific, statistical investigation of their reliability as compared to the traditional gold standard-plaster models in the form of a meta-analysis. OBJECTIVES: To evaluate the reliability and reproducibility of measurements taken on digital orthodontic models obtained from scanning plaster models in laboratory scanners compared to measurements taken directly on plaster models. SEARCH METHODS: Multiple electronic databases (PubMed, Scopus, Web of Science, Google Scholar and Cochrane Central Register of Controlled Trials) were searched for articles with no year or language limitations. SELECTION CRITERIA: The included original papers should have dealt with the accuracy and repeatability of the measurements conducted on plaster and digital models derived from laboratory scanners. In order to provide an adequate statistical analysis, the studies should have provided sufficient data, that is the difference of means (MDs) with standard deviations (SDs) for analysed measurements. DATA COLLECTION AND ANALYSIS: In total, 25 types of non-standardised measurements were found in the evaluated studies. The quantitative analysis included papers that compared at least one of the parameters: upper/lower intermolar width, upper/lower intercanine width, overjet and overbite and provided standard deviation of the mean differences between measurements obtained on plaster and digital models from a laboratory scanner. RESULTS: GRADE and QUADAS tools were used to assess the quality of evidence, and they revealed substantial heterogeneity. Random-effects meta-analysis revealed no statistically significant differences for analysed measurements. Four of the analysed papers reported differences that may be considered clinically significant. CONCLUSIONS: No statistical significance between the direct measurements on plaster models and the digital ones taken from laboratory scanners could be identified by means of random-effects meta-analysis. REGISTRATION: The systematic review was registered in the PROSPERO database (ID CRD42020215411).

Investigation of salivary biomarkers as indicators of skeletal and dental maturity in children.

OBJECTIVE: Estimation of patient's skeletal maturity in orthodontics is essential for the diagnosis and treatment planning. The aim of the study was to investigate the potential use of metabolic fingerprint of saliva for bone growth and tooth development estimation. MATERIALS AND METHODS: Saliva samples from 54 young patients were analysed by an untargeted gas chromatography-mass spectrometry metabolomics-based method. The skeletal maturity was calculated with the cervical vertebrae maturation method, and the dental age was estimated with the Demirjian method. Multivariate analysis and univariate analysis were performed to investigate differences within skeletal, dental and chronological age groups. RESULTS: Metabolomic analysis identified 61 endogenous compounds. Mannose, glucose, glycerol, glyceric acid and pyroglutamic acid levels differentiated significantly with skeletal age (P = .02 to .043), while mannose, lactic acid, glycolic acid, proline, norleucine, 3-aminoisobutyric acid, threonine, cadaverine and hydrocinnamic acid levels differed within the dental age groups (P = .018 to .04); according to the chronological age, only the levels of mannose and 3-hydroxyphenylacetic acid showed variation (P = .029 and .048). The principal component analysis did not manage to highlight differences between the groups of the studied parameters. CONCLUSION: Differentiated levels of mannose, glucose, glycerol, glyceric acid and pyroglutamic acid related to skeletal maturation were identified. According to dental development, the levels of mannose, lactic acid, glycolic acid, proline, norleucine, 3-aminoisobutyric acid, threonine, cadaverine and hydrocinnamic acid differed within the groups, while regarding chronological age, only the levels of mannose and 3-hydroxyphenylacetic acid showed variations. Further studies are required to prove their relation to skeletal and dental development pathway by applying complementary analytical techniques to wider cover the metabolome.

Color changes of maxillary and mandibular incisors following surgical orthodontic treatment : A prospective controlled clinical pilot study.

OBJECTIVE: To assess possible color changes of natural teeth after surgical orthodontic treatment. METHODS: This prospective controlled clinical pilot trial included 6 consecutively treated surgical orthodontic patients with class III malocclusion and neutral vertical relation (ST: surgical treatment), 3 of which received double jaw osteotomies (SGI: surgical subgroup I) and 3 received single mandibular sagittal split ramus osteotomies (SGII: surgical subgroup II). Eleven untreated individuals (UC: untreated control) and 9 individuals who received conventional comprehensive orthodontic treatment only (OC: orthodontic control) served as controls. Tooth color measurements were performed using a reflectance spectrophotometer on the upper and lower incisors before the initiation of the surgical orthodontic treatment (T1) and after its completion (T2). Primary endpoint was ∆E* (T1-T2) of summarized CIE-L*a*b* color differences. The null hypothesis of this study was that there is no statistically significant change in total tooth color difference ∆E* CIE-(L*a*b*) in vivo at baseline and following surgical orthodontic treatment. RESULTS: There was a statistically significant increase in ∆E* (T1-T2) in the ST group compared to the UC and OC groups. Single mandibular surgery had a stronger effect on the lower teeth in comparison to double jaw surgery, while Le Fort I osteotomy, as part SGI, had a stronger effect on the upper teeth. Despite statistical significance, the majority of mean values of these color changes were lower than the threshold value of color alterations considered to be perceivable by the naked eye in a clinical setting (3.7 ∆E units), with the exception of the mandibular incisors in SGII, where this threshold value was slightly exceeded. CONCLUSIONS: Orthognathic surgery showed a measurable effect on tooth color. However, esthetic disturbance or patient discomfort based on these color and lightness alterations are unlikely, due to their small impact and low perceptibility in a clinical setting.

Complications reported with the use of orthodontic miniscrews: A systematic review.

OBJECTIVE: The aim of this systematic review was to evaluate the complications and side effects associated with the clinical use of orthodontic miniscrews by systematically reviewing the best available evidence. METHODS: A survey of articles published up to March 2020 investigating the complications associated with miniscrew insertion, in both the maxilla and mandible, was performed using 7 electronic databases. Clinical studies, case reports, and case series reporting complications associated with the use of orthodontic miniscrew implants were included. Two authors independently performed study selection, data extraction, and risk-of-bias assessment. RESULTS: The database survey yielded 24 articles. The risk-of-bias assessment revealed low methodological quality for the included studies. The most frequent adverse event reported was root injury with an associated periradicular lesion, vitality loss, pink discoloration of the tooth, and transitory loss of pulp sensitivity. Chronic inflammation of the soft tissue surrounding the miniscrew with mucosal overgrowth was also reported. The other adverse events reported were lesion of the buccal mucosa at the insertion site, soft-tissue necrosis, and perforation of the floor of the nasal cavity and maxillary sinus. Adverse events were also reported after miniscrew removal and included secondary bleeding, miniscrew fracture, scars, and exostosis. CONCLUSIONS: These findings highlight the need for clinicians to preliminarily assess generic and specific insertion site complications and side effects.

Upper airway volumetric changes of obstructive sleep apnoea patients treated with oral appliances: a systematic review and meta-analysis.

BACKGROUND: Obstructive sleep apnoea (OSA) is a common sleep-related breathing disorder, attributed to the collapse of the pharyngeal walls and the subsequent complete or partial upper airway obstruction. Among different treatment options for OSA, Continuous Positive Airway Pressure, and oral appliances (OAs) have been used, with various outcomes and side effects. OBJECTIVE: The aim of this study was to summarize current knowledge in an evidence-based manner regarding the upper airway volume increase of OSA patients while treated with OAs. SEARCH METHODS: Electronic search was conducted in Pubmed, Cochrane Library, and Scopus, up to May 2020. SELECTION CRITERIA: Studies were selected after the application of predetermined eligibility criteria. DATA COLLECTION AND ANALYSIS: Mean airway volume differences and the corresponding 95% confidence intervals were calculated, using the random effects model. Sensitivity, exploratory, and meta-regression analyses were also implemented. RESULTS: Eleven studies filled the inclusion criteria and were included in the systematic review, while 10 of them were suitable for meta-analysis. In total, 291 patients were included, with mean upper airway volume increase of 1.95 cm3 (95% CI, 1.37-2.53; P < 0.001) with Mandibular Advancement Devices in place. In all studies, post-treatment Apnea Hypopnea Index (AHI) was either <10 events/hour or was reduced by more than 50% from baseline levels. A greater increase of the velopharynx volume was observed, regarding airway compartments. CONCLUSIONS: Treatment with OAs in OSA may lead to a significant increase of the upper airway volume with a subsequent decrease of AHI. The velopharynx seems to be affected the most from OA therapy.

Efficient Distalization of Maxillary Molars with Temporary Anchorage Devices for the Treatment of Class II Malocclusion.

Treatment of Class II malocclusion often requires maxillary molar distalization. However, when applying distalization forces on the maxillary molars, anchorage loss may occur in different degrees not only during molar distalization (such as distal tipping of maxillary molars and mesial movement and proclination of the anterior teeth) but also during the subsequent stage of anterior teeth retraction (such as mesial movement of maxillary molars). All these movements are considered as unwanted side effects, which diminish the clinical effectiveness of distalization. Miniscrew implants can be used as temporary anchorage devices (TADs) to enhance anchorage and, if properly used, to counterbalance the side effects. Among the different available systems, the TAD-supported amda® can be considered as a simple, noncompliant, minimally invasive, and very efficient approach that can be used for the comprehensive treatment of patients with Class II malocclusion not only to distalize the maxillary molars bodily without or with minimal distal tipping and without proclination of the anterior teeth but also in combination with full-fixed appliances to retract and intrude the anterior teeth.

Are orthodontic landmarks and variables in digital cephalometric radiography taken in fixed and natural head positions reliable?

OBJECTIVE: The purpose of the study was to evaluate the reliability of the most common landmarks and variables in digital lateral cephalometric radiographies in fixed and natural head positions. MATERIALS AND METHODS: Twenty-one patients with anterior or distal displacement of the mandible treated in the Postgraduate Orthodontic Clinic of the Aristotle University of Thessaloniki had a digital lateral cephalometric radiography in fixed and in natural head position. The images where digitized. The main investigator and 6 examiners, digitized 61 landmarks and analysed 34 variables. We examined the intra-observer and inter-observer variability. RESULTS: There was a significant difference in X-axis in the distribution (hence the mean results) according to the reliability of the landmarks and in only 2 variables in digital lateral cephalograms between fixed and natural head position. CONCLUSIONS: Cephalometric landmarks and variables showed reliability in digital lateral cephalometric radiography in fixed and natural head position. In lateral cephalograms taken in fixed head position an anterior inclination of the head was noticed compared to those in natural head position.

Effects of systematic bisphosphonate use in patients under orthodontic treatment: a systematic review.

BACKGROUND: Bisphosphonates are a class of drugs prescribed for several osseous related disorders owing to their ability to regulate bone turnover, which could in turn affect orthodontic treatment outcomes. OBJECTIVE: To examine the effect of bisphosphonate (BP) use on orthodontic patients through clinical and radiographic measurements. SEARCH METHODS: Systematic and unrestricted search of 17 databases complemented with additional hand-searches were performed up to March 2019. SELECTION CRITERIA: Articles reporting on human patients with a history of BPs administration that received orthodontic treatment were eligible for inclusion. DATA COLLECTION AND ANALYSIS: Data regarding the medical profile of the patients, the specific type of malocclusion and the performed treatment plan, as well as the clinical and radiographic outcomes were extracted. Quality assessment was performed by the ROBINS-I tool for the cohort studies and by a slightly modified checklist from the original one proposed by Agbabiaka et al. for the case reports. RESULTS: 7 articles (1 retrospective cohort study and 6 case reports) were eventually included in the present review including 122 subjects (29 patients and 93 controls) reporting on the clinical and radiographic changes following orthodontic treatment of patients during or after BPs use. BPs seem to have a controversial effect on the clinical and patient-reported variables, even though the majority of the included patients presented with compromised treatment results and a rather slow rate of tooth movement. Most radiographic findings revealed mild root resorption, widened periodontal ligament spaces and sclerotic changes on the surrounding alveolar bone. However, these results should be interpreted with caution, due to the limited number of the eligible articles and their limitations. LIMITATIONS: The included studies were of rather low quality due to study design and incomplete reporting. CONCLUSIONS AND IMPLICATIONS: BP administration seems to be associated with compromised clinical outcomes, prolonged treatment time, and moderate changes on the roots and surrounding tissues of orthodontic patients. REGISTRATION: Non-registered. FUNDING: None.

Prevention of orthodontic enamel demineralization: A systematic review with meta-analyses.

Aim of this systematic review was to assess the efficacy of preventive interventions against the development of white spot lesions (WSLs) during fixed appliance orthodontic treatment. Nine databases were searched without limitations in September 2018 for randomized trials. Study selection, data extraction and risk of bias assessment were done independently in duplicate. Random-effects meta-analyses of mean differences (MDs) or relative risks (RRs) with their 95% confidence intervals (CIs) were conducted, followed by sensitivity analyses, and the GRADE analysis of the evidence quality. A total of 24 papers (23 trials) were included, assessing preventive measures applied either around orthodontic brackets (21 trials; 1427 patients; mean age 14.4 years) or molar bands (2 trials; 46 patients; age/sex not reported). Active patient reminders were associated with reduced WSL incidence on patient level compared to no reminder (3 trials; 190 patients; RR: 0.4; 95% CI: 0.31-0.64; Number Needed to Treat [NNT]: 3 patients), flat surface sealants were associated with reduced WSL incidence on tooth level than no sealant (5 trials; 2784 teeth; RR: 0.8; 95% CI: 0.63-0.95; NNT: 33 teeth), and fluoride varnish was associated with reduced WSL severity on tooth level (2 trials; 1160 teeth; MD: -0.32 points; 95% CI: -0.44 to -0.21 points). However, the quality of evidence was low according to GRADE, due to risk of bias. Some evidence indicates that active patient reminders and flat surface sealants or fluoride varnish around orthodontic brackets might be associated with reduced WSL burden, but further research is needed.

In vivo evaluation of tooth colour alterations during orthodontic retention: A split-mouth cohort study.

OBJECTIVES: To assess in vivo colour alterations of teeth following removal of fixed orthodontic appliances during retention. SETTING AND SAMPLE POPULATION: The Department of Orthodontics at the Aristotle University of Thessaloniki. Forty-eight patients after orthodontic treatment. MATERIAL AND METHODS: Debonding and cleaning procedures after orthodontic treatment were performed using two different carbide burs attached to a low or high-speed handpiece, respectively, in a non-blinded cohort study with split-mouth design. Spectrophotometric colour data of teeth were recorded: (a) after debonding, (b) three months later, prior to and following finishing with Soflex discs, and (c) after 1 year. The CIE Lab colour parameters were measured for each tooth, and the corresponding ΔΕ differences were calculated. The effect on colour was assessed with 3-way mixed ANOVA and Bonferroni's comparisons test (a < 0.05). RESULTS: Orthodontic debonding and cleaning procedures were found to have statistically significant effects on the CIE colour parameters of treated teeth, since the L* values decreased 0.6 units (P < 0.001), a* values were stable (0.0 units) and b* values increased 1.4 units (P < 0.001), during the first retention year. Finishing temporarily decreased the enamel colour differences. Total ΔΕ differences for all types of teeth measured ranged from 1.4 to 2.1 units. The greatest changes were exhibited during the first 3 months in teeth on which high-speed rotary instruments were used (1.6 units). CONCLUSION: The clinical relevance of this study points out that the colour of natural teeth following removal of fixed orthodontic appliances changes in long-term.

Evaluation of orthodontically induced external root resorption following orthodontic treatment using cone beam computed tomography (CBCT): a systematic review and meta-analysis.

Background: Orthodontically induced external root resorption (OIRR) is a pathologic consequence of orthodontic tooth movement. However, the limitations of two-dimensional radiography suggest that cone beam computed tomography (CBCT) with its three-dimensional capabilities might be more suitable to assess OIRR. Objective: The aim of this study was to assess in an evidence-based manner data on linear or volumetric OIRR measurements of permanent teeth by means of CBCT, during and/or after the end of orthodontic treatment. Search methods: Unrestricted electronic and hand searches were performed up to January 2017 in 15 databases. Selection criteria methods: Randomized clinical trials, prospective, and retrospective non-randomized studies assessing OIRR during and/or after orthodontic treatment using CBCT in human patients were included. Data collection and analysis: After duplicate study selection, data extraction, and risk-of-bias assessment according to the Cochrane guidelines, random-effects meta-analyses, followed by subgroup, meta-regression, and sensitivity analyses were also performed in order to evaluate factors that affect OIRR. Results: A total of 33 studies (30 datasets) were included in the qualitative analysis while data from 27 of them were included in the quantitative analysis. Direct comparisons from randomized trials found little to no influence of appliance-related factors on OIRR. Explorative analyses including non-randomized studies found a pooled OIRR of 0.79 mm based on all included studies and 0.86 mm when OIRR was assessed at the end of orthodontic treatment. Statistically significant differences in OIRR were found according to tooth type or jaw, inclusion of extractions, treatment duration, and diagnostic accuracy of the CBCT. Conclusions: Based on the results of this study, CBCT seems to be a reliable tool to examine OIRR during or at the end of orthodontic treatment. Although the average OIRR measured with CBCT seems to lack clinical relevance, there are certain factors that may affect OIRR following orthodontic treatment. Nevertheless, due to data heterogeneity and low quality of the included studies, the corresponding results should be interpreted with some caution. Registration: PROSPERO (CRD42016030131).

Dentoalveolar characteristics in children with juvenile idiopathic arthritis.

PURPOSE: Juvenile idiopathic arthritis (JIA) is an autoimmune disease with multiple potential causal factors. In case of temporomandibular joint (TMJ) affection, the inflammatory reaction can result in restricted mandibular growth with implied skeletal and facial deformities. Aim of the present study was to examine dentoalveolar and occlusion characteristics in children with JIA. PATIENTS AND METHODS: The sample consisted of 66 children (27 boys, 39 girls) with JIA. Thirty-three of them showed unilateral or bilateral condylar destruction, while the other half did not manifest any TMJ involvement. Corresponding dental casts of these patients were evaluated and Angle classification, overjet, overbite, crossbite, crowding, and ectopic teeth were registered. All dental casts were subsequently scanned and digitized to analyze 26 additional variables. Subgroups according to sex and condylar affection were formed. Statistical analysis was performed using Fisher's least significant difference (LSD) post hoc test of analysis of variance (ANOVA). RESULTS: The prevalence of Class II, division 1 malocclusion in this JIA sample was high (28.8%). Compared to girls, boys had significantly greater dental arch widths and lengths. The group with bilateral condylar affection had significantly decreased lower arch length and increased irregularity index (p < 0.035) compared to the non-affected group. CONCLUSIONS: Bilateral condylar involvement in children with JIA seems to reduce the lower arch length, while increasing the irregularity index of the lower front teeth.

Skeletal and Dental Effectiveness of Treatment of Class II Malocclusion With Headgear: A Systematic Review and Meta-analysis.

OBJECTIVE: To evaluate the skeletal and dental effects of headgear treatment by systematically reviewing the best available scientific evidence. MATERIALS AND METHODS: A survey of articles published up to February 2017 investigating the effects of headgear in the treatment of patients with class II malocclusion was performed using 19 electronic databases. Only randomized clinical trials and prospective controlled clinical trials investigating growing patients with class II malocclusion treated with headgear were included. Two authors performed independently study selection, data extraction, and risk of bias assessment. All pooled data analyses were performed using the random-effect model. Statistical heterogeneity was evaluated. RESULTS: In total, 6 trials were included (4 randomized clinical trials and 2 prospective controlled clinical trials), grouping data from 337 patients (170 treated patients and 167 untreated controls). The ages of the patients varied across the studies, but the majority of the trials had a sample with an age range between 8 and 9 years. The times of daily wear of the appliance varied across studies from 8 to 14 h/d. The significant mean differences in treatment effects compared with the untreated controls were -1.41° per year for SNA angle cephalometric parameter (95% confidence interval [CI]: -2.25° to -0.56°), -0.57 mm/y for anterior maxillary displacement (95% CI: -0.75 to -0.40 mm), -1.42° per year for ANB angle cephalometric parameter (95% CI: -2.12° to -0.72°), and -1.31 mm/y for the overjet cephalometric parameter (95% CI: -2.34 to -0.29 mm). CONCLUSION: Headgear treatment is effective in restricting sagittal maxillary growth and reducing the overjet in the short term.