Digital setup accuracy for moderate crowding correction with fixed orthodontic appliances: a prospective study.

OBJECTIVES: To evaluate the accuracy of a semi-automatic 3D digital setup process in predicting the orthodontic treatment outcome achieved by labial fixed appliances. SUBJECTS AND METHODS: Twenty-five adult patients (18 to 24 years old) with class I malocclusion and moderate crowding were prospectively enrolled and received treatment on both jaws through the straight-wire technique. Prior to treatment commencement, a semi-automatic digital setup simulating the predicted treatment outcome was performed for each patient through Orthoanalyzer software (3Shape®, Copenhagen, Denmark) to obtain the prediction model. This was compared to the final outcome model through 3D superimposition methods. Metric variables and inspection of color-coded distance maps were used to detect how accurately the digital setup predicts the actual treatment outcome. RESULTS: The mean absolute distances (MAD) between the superimposed dental arches of the predicted and the final models were: 0.77 ± 0.13 mm following superimposition on the palate, 0.52 ± 0.06 mm following superimposition on the maxillary dental arch, and 0.55 ± 0.15 mm following superimposition on the mandibular dental arch. The MAD at the palatal reference area was 0.09 ± 0.04 mm. Visualization of color-coded distance maps indicated that the digital setup accurately predicted the final teeth position in a few cases. Almost half of the cases had posteriorly wider upper and lower dental arches and palatally/lingually positioned or inclined anterior teeth, whereas the rest still showed errors within 2-3 mm, distributed over the entire dental arches with no distinct pattern. CONCLUSIONS: The accuracy of semi-automatic prediction of the labial fixed appliance treatment outcome in Class I cases with moderate crowding is not yet sufficient. While average measures showed deviations less than 1 mm, examination of individual color-coded distance maps revealed significant disparities between the simulated and the actual results.

Comparison study of chewing efficiency in patients with different vertical skeletal patterns of Angle Class I and Angle Class II malocclusions.

OBJECTIVE: The purpose of this study was to analyze and compare the differences in chewing efficiency among patients with different vertical skeletal types of Angle Class I and Angle Class II malocclusions, to provide reference for orthodontic clinical practice. METHOD AND MATERIALS: Sample size estimation revealed a minimum of 53 for each class. Thus, a total of 108 patients with Angle Class I and Angle Class II malocclusions were selected. Lateral skull radiographs were taken, and head measurements were analyzed via geometric tracing software. Chewing efficiency was measured using the gravimetric method to compare between the two groups. The vertical skeletal pattern was classified via Steiner analysis. RESULTS: Significant statistical differences in chewing efficiency were observed between patients presenting with Angle Class I and Angle Class II malocclusions (P < .05). Additionally, significant differences in chewing efficiency were observed among patients with different vertical skeletal patterns (P < .05). Furthermore, a statistically significant difference in chewing efficiency was found between men and women (P < .05). CONCLUSIONS: Patients with Angle Class I malocclusions exhibited significantly higher chewing efficiency compared to those with Angle Class II malocclusions. Among patients with different vertical facial types, the chewing efficiency followed the order of low angle > normal angle > high angle. Moreover, men demonstrated a higher chewing efficiency than women.

Evaluation of pharyngeal airway volume three-dimensionally in various sagittal skeletal patterns - Systematic review.

To investigate the pharyngeal airway volume in different anteroposterior skeletal malocclusions. This study was prepared according to the Cochrane criteria for creating a systematic review and meta-analysis and confirms the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement. This search was conducted to answer the patient/population, intervention, comparison and outcomes (PICO) question: To evaluate (outcome) and compare (comparison) whether there is a difference in airway volume in patients (participants) with different skeletal malocclusions diagnosed using 3D data (intervention).The first two authors extracted the data from the included studies and assessed the risk of bias in the individual studies using the Newcastle-Ottawa scale. Meta-analysis was done using STATA version 16, which compared various three-dimensional pharyngeal airway parameters in skeletal Class II and skeletal Class III malocclusions with that of skeletal class I malocclusion. Out of 370 articles from the initial search, 17 articles were included in the systematic review. Out of 17 studies, 12 eligible studies were included in the quantitative synthesis. The nasopharynx, oropharynx, hypopharynx, and total airway volume were increased in skeletal Class I malocclusion compared to that of skeletal Class II malocclusion and decreased in comparison to skeletal Class III malocclusion. The moderate quality of evidence indicates the total airway volume, oropharynx, and hypopharynx are largest in skeletal Class III compared to Class I and Class II skeletal malocclusion.

Treatment effectiveness of young adults using clear aligners versus buccal fixed appliances in class I malocclusion with first premolar extraction using the ABO-Objective Grading System: A randomized controlled clinical trial.

OBJECTIVE: To compare the effectiveness of the clear aligners with the traditional fixed appliances in the treatment of premolars extraction complex cases using the American Board of Orthodontics Objective Grading System (ABO-OGS). MATERIAL AND METHODS: A single-centre, 2-parallel groups RCT with two arms. Forty severe crowding patients (14 males, 26 females; mean age: 21.40±2.42) who required four first premolars extraction were included and randomly allocated into two treatment groups: clear aligners therapy group (CAT), and fixed appliances therapy group (FAT). Cases complexities were measured on pre-treatment records using the Discrepancy index (DI). Post-treatment records were evaluated using the American Board of Orthodontics Objective Grading System (ABO-OGS). Two sample t-tests and Fisher's Exact tests were used to test for significant differences between the two groups. The statistical significance was set at P < 0.006 using Bonferroni's correction. RESULTS: For the DI, the mean scores were 32.25 (± 4.33) in the CAT group and 33 (± 7.92) in the FAT group. In the CAT group, the total OGS score ranged between 6-33 points with an average of 17.50(± 7.41), whereas the total score in the FAT group went between 4-30 points with an average of 12.89 (± 6.31) with no significant differences between the two groups (P=0.05). When comparison of the successful cases between the two groups was made, 11 cases received passing scores, and 9 cases received failing scores in the CAT group. Whereas in the FAT group, 17 cases received passing scores, and 3 received a failing score. No statistically significant differences were found in the passing rates between of the CAT and FAT groups (P = 0.421). CONCLUSIONS: According to the ABO-OGS total scores, there was no significant difference between the clear aligners and fixed appliances in the treatment of class I severe crowding cases with first premolars extraction in young adults. There were no differences between the two techniques in the OGS components scores except for the occlusal contacts, which were significantly better with the fixed appliances. When comparing the number of successful and failed cases between the two groups, no significant differences were noted, with the fixed appliances having a 30% higher success rate than the clear aligners, which must be considered clinically when choosing between these two techniques in the complex orthodontic cases treatment.

Relationship between vertical facial morphology and dental arch measurements in class II malocclusion: a retrospective study.

Background: To evaluate the relationship between dental arch measurements and the vertical facial pattern determined in skeletal Class II untreated patients. Methods: Lateral cephalograms and plaster models were obtained from 124 untreated female adults (average age: 17.6 ± 3.8 years). Class I (CI), Class II Division 1 (CII/1) and Class II Division 2 (CII/2) malocclusions were divided into three subgroups according to their vertical morphology as hypodivergent, normodivergent and hyperdivergent. The multivariate variance analysis (MANOVA) method was used in the comparison of measurement values according to vertical and sagittal morphology. The relationship between both A point-Nasion-B point (ANB) and Frankfurt-mandibular plane (FMA) angles and dental arch measurements was examined by Pearson correlation analysis. The significance level was received as p < 0.05. Results: While vertical morphology has a statistically significant effect on mandibular arch length, sagittal morphology affects maxillary arch depth. The parameters influenced by both morphologies are maxillary and mandibular arch length, as well as maxillary intermolar width. The mandibular arch length was significantly shorter in hyperdivergent-CII-2 malocclusion (50.5 ± 7.4 mm). Larger values were obtained in both mandibular arch length and maxillary arch depth measurements in CII-1 malocclusion compared to CII-2 malocclusion. The maxillary intermolar width was significantly shorter in hypodivergent-CII-1 malocclusion (46.8 ± 3.4 mm), while it was higher in hypodivergent-CI malocclusion (51.1 ± 3.4 mm). The maxillary arch length was the lowest in hyperdivergent-CI malocclusion (63.1 ± 13.3 mm) and the highest in hypodivergent-CI malocclusion (72.8 ± 7.6 mm). Additionally, a positive but weak correlation was found between ANB and FMA angles. Conclusion: Dental arch measurements have been found to be affected by both vertical facial morphology and skeletal sagittal relationship. A positive correlation was found between ANB and FMA angles.

Geometric analysis of tooth size among different malocclusion groups in a Hispanic population.

INTRODUCTION: Tooth size ratio is important for optimal dentofacial esthetics, occlusal interdigitation, and postorthodontic treatment stability. Tooth geometry influences tooth size ratio; therefore, tooth size normative data may not be practical across diverse ethnic groups. This study aimed to determine whether there are significant differences in 3-dimensional tooth size among patients in the Hispanic population with Angle Class I, II, and III malocclusions. METHODS: The data were collected using intraoral scanned orthodontic study models representing Hispanic orthodontic patients with Angle Class I, II, and III malocclusions. The scanned models were digitized and transferred to a geometric morphometric system. Tooth sizes were determined, quantified, and visualized using contemporary geometric morphometric computational tools. RESULTS: Tooth size was determined for all teeth and showed a significant difference in 4 out of 28 teeth: Maxillary right first molar, mandibular left second molar, mandibular right first molar and mandibular right second molar. This significant difference was noted among females and affected different malocclusion groups. CONCLUSIONS: Tooth size discrepancy in the Hispanic population varies among malocclusion groups, and the variation is determined by the participant's gender.

[The impact of masticatory muscles hypertonicity on the bite formation]. / Vliyanie gipertonusa zhevatel'noi muskulatury na formirovanie okklyuzii.

THE AIM OF THE STUDY: Was to assess the impact of masticatory muscles hypertonicity on the bite formation. MATERIALS AND METHODS: The study comprised 60 patients aged 7-14 years. Group 1 consisted of 20 individuals with Angle class 1 occlusion without masticatory muscle hypertonicity. Group 2 comprised 20 patients with class II malocclusion with hypertonicity of the masticatory muscles, group 3 - 20 patients class II malocclusion and no hypertonic masticatory muscles. All patients were examined according to common diagnostic protocol that included electromyography of the temporal and masticatory muscles at rest and in dynamics). RESULTS: In group 1 the mean IMPACT at rest was 242.8±133.6 µV, IMPACT during contraction was 880.50±201.5 µV; in group 2 - 797.9±413.0 and 1561.23±568.0 µV; in group 3 - 236.7±93.5 and 955.60±295.5 µV, correspondingly. The ratio of the activity of the temporal muscles to the masticatory muscles with neutral occlusion at rest correlates as 1:09, with compression 1:1. In patients with distal occlusion and the presence of hypertonicity at rest, the temporal muscles correspond to the chewing proper as 1:0.8, and with compression 1:09. CONCLUSION: The estimated ratio can contribute to the retroposition of the mandible, as well as inhibition of the growth of the mandible in the sagittal direction.

The predictability of maxillary curve of Wilson leveling with the Invisalign appliance.

BACKGROUND: This retrospective study aims to evaluate the predictability of the Invisalign appliance (Align Technology, Santa Clara, CA) in leveling the maxillary curve of Wilson (COW). METHODS: 53 adult subjects treated by orthodontists who are experienced Invisalign providers, between 2013 and 2019 were selected. All patients had either Angle Class I or II malocclusions and were treated by non-extraction in the maxillary arch with a minimum of 14 Invisalign aligners with no bite ramps or auxiliaries. Initial, predicted, and actual outcomes were analyzed with Geomagic Control X software (3D systems, Rock Hill, SC; Version 2017.0.3). RESULTS: Despite planning mean (SD) COW leveling of 0.25 mm (1.91), the curve became significantly more pronounced by 1.15 mm (0.85) (P < .001). There was a significant overexpression of buccal inclinations between mean prescribed versus actual values from 0.10 mm (0.39) (P = .007) to 0.29 mm (0.47) (P < .001) from the first premolars to the second molars, respectively. These differences were more pronounced posteriorly. The differences between the predicted and actual arch width values were underexpressed for all teeth except the second molars; a mean underexpression between 0.28 mm (0.92) and 0.60 mm (1.14). The second molars were the only teeth to overexpress with a mean of 0.42 mm (1.02). CONCLUSIONS: Overall mean maxillary COW was not predictably controlled with Invisalign. The appliance tends to overexpress the buccal crown tip regardless of prescribed direction, especially posteriorly. Arch expansion was underexpressed at all levels of the arch except for second molars which overexpressed by almost four times.

The predictability of maxillary curve of Spee leveling with the Invisalign appliance.

OBJECTIVES: To evaluate the predictability of the Invisalign appliance (Align Technology, Santa Clara, Calif) in leveling the maxillary curve of Spee (COS). MATERIALS AND METHODS: A retrospective sample of adult subjects treated with the Invisalign appliance between 2013 and 2019 were selected. Patients were treated nonextraction in the maxillary arch and had either Angle Class I or II malocclusions with a minimum of 14 aligners with no bite ramps. Initial, predicted, and actual outcomes were analyzed with Geomagic Control X software (version 2017.0.3; 3D Systems, Cary, NC). RESULTS: A sample of 53 cases satisfied inclusion/exclusion criteria. Paired t-tests demonstrated a significant difference between mean predicted and actual maxillary COS leveling with a shortfall of 0.11 mm (SD = 0.37; P = .033). Planned intrusion tended to be more accurate posteriorly with an overexpression of 117% for the first molars. Planned extrusion was the least accurate, with the mid-arch demonstrating expressions of -14% to -48%. These teeth intruded despite a prescribed extrusive movement. CONCLUSIONS: The Invisalign appliance did not accurately predict maxillary COS leveling. Planned intrusive movements were overcorrected, and planned extrusive movements were either undercorrected or resulted in intrusion. This effect was most apparent for the upper first molar, which expressed 117% and -48% of planned intrusion and extrusion, respectively.

Morphometric analysis of tooth morphology among different malocclusion groups in a hispanic population.

BACKGROUND: There have been reports of unique dental morphological features amongst Latin American and Hispanic populations, and this might invalidate the use of current orthodontic diagnostic tools within this population. There are no tooth size/tooth ratio normative standards for the Hispanic population, despite overwhelming evidence about differences in tooth size between racial groups. OBJECTIVE: This study aimed to determine whether there are significant differences in 3-D tooth shape between patients with Angle Class I, Class II, and Class III dental malocclusion in the Hispanic population. METHODOLOGY: Orthodontic study models representing Hispanic orthodontic patients with Angle Class I, II, and III dental malocclusions scanned using an intra-oral scanner. The scanned models were digitized and transferred to a geometric morphometric system. Tooth size shape were determined, quantified, and visualized using contemporary geometric morphometric computational tools using MorphoJ software. General Procrustes Analysis (GPA) and canonical variates analysis (CVA) used to delineate the features of shape that are unique to each group. RESULT: The study revealed differences in tooth shape between the different dental malocclusion groups on all twenty-eight teeth that were studied; the pattern of shape differences varied between the teeth and the dental malocclusions. The MANOVA test criteria, F approximations, and P-values show that shape in all the groups was significantly different < 0.05. CONCLUSION: This study revealed differences in tooth shape between the different dental malocclusions on all teeth, and the pattern of shape differences varied between the different dental malocclusions group.

Effect of the vertical facial pattern on the developmental relationship between the nasal bone and maxillary central incisors.

BACKGROUND: This study aimed to investigate the effect of vertical facial patterns on the developmental relationship between the nasal bone and maxillary central incisors. METHODS: In this retrospective comparative study, the lateral cephalograms of 213 subjects (51 Males, 162 Females) with skeletal Class I malocclusion (aged 18-32 years) were classified into three equal groups: (1) hyperdivergent, (2) normodivergent, and (3) hypodivergent facial patterns based on the mandibular plane inclination (S-N/Go-Me). Several sets of measurements were extracted: (1) gradient and length of the nasal bone and maxillary central incisor, (2) the distance from apex and root of the nasal bone, and (3) maxillary central incisor to the true perpendicular from the digitized lateral cephalograms. The significance level was considered at P < 0.05. RESULTS: The inclination angle and length between nasal bone and maxillary central incisor were positively correlated independent of vertical facial type. The inclination angle of the nasal bone in the hypodivergent group was significantly larger than the other two vertical facial patterns. The inclination angle of the maxillary central incisor increased successively in the hyperdivergent, normodivergent, and hypodivergent groups. The length of the nasal bone in the hyperdivergent group was significantly longer than that in the hypodivergent and normodivergent groups. The maxillary central incisor length in the hyperdivergent group was significantly longer than in the hypodivergent group. CONCLUSION: A correlation between nasal bone and maxillary central incisors during the growth and development of the maxillofacial region was found. In Class I malocclusion subjects, hypodivergent patients were more likely to have a prominent and relatively short nasal bone and maxillary central incisors and vice versa.

Análisis bidimensional de la permeabilidad de vías aéreas con el tamaño de senos maxilares y su relación con el desarrollo de la clase esqueletal en una población mexicana / Two-dimensional analysis of airway permeability with maxillary sinus size and its relationship with the development of skeletal class in a Mexican population

Comparar la permeabilidad de las vías aéreas y el tamaño de los senos maxilares en relación con la clase esqueletal. se midieron 90 radiografías lateral de cráneo, divididas en 3 grupos, comparando las 3 clases esqueletales, las cuales se determinaron con la medida ANB de Steiner, y estas a su vez en dos subgrupos que fueron hombres y mujeres, en las cuales se utilizó el análisis de McNamara para el análisis de vías aéreas y para el área del seno maxilar se tomaron dos medidas una antero-posterior y cefálica-caudal. Al comparar los hombres con las mujeres se identificó significancia estadística en vía área superior de clase II (p=≤0.017), vía aérea inferior de clase III (p=≤0.006). Al comparar las clases esqueletales en hombres se identificó diferencias en la vía aérea superior en las clases I vs III (p=≤0.05), inferior en la clase I vs III (p=≤0,001) y II vs III (p=≤0.044). Con respecto a mujeres se identificó significancia en la vía aérea superior al comparar la clase I vs II (p=≤0,043), vía aérea inferior en la clase II vs III (p=≤0.05), longitud del seno maxilar al comparar clase I vs II (p=≤0.017). Entre la clase I esqueletal y la clase II, el tamaño de los senos maxilares resulto menor en longitud en las mujeres de clase II esqueletal. Entre la clase I y clase III esqueletal en hombres, se encontró una longitud menor en la vía aérea superior e inferior en la clase I. Las vías aéreas resultaron en menor tamaño en sujetos de clase II.

SUMMARY: To compare the airway permeability and the size of the maxillary sinuses in relation to the skeletal class. 90 lateral skull radiographs were divided into 3 groups, comparing the 3 skeletal classes, which were determined with Steiner's ANB measurement, and these were once in two subgroups that were men and women, in any McNamara analysis was used for the analysis of airways and for the maxillary sinus area measurements were made an antero-posterior and cephalic-caudal. When comparing males with females, statistical significance was identified in the upper class II route (p=≤0,017), lower class III airway (p=≤0.006). At least skeletal classes in men, differences were identified in the upper airway in classes I vs III (p=≤0.05), lower in class I vs III (p=≤0.001) and II vs III (p=≤0.044). With respect to women, significance was identified in the upper airway when comparing class I vs II (p=≤0.043), lower airway in class II vs. III (p=≤0.05), maxillary sinus length to class I vs II (p=≤0.017). Between skeletal class I and class II, maxillary sinus size was shorter in length in skeletal class II women. Between class I and skeletal class III in men, a lower length was found in the upper and lower airways in class I. The airways were found to be smaller in class II subjects.

Evaluation of the predicted vs. achieved occlusal outcomes with the Invisalign® appliance: A retrospective investigation of adult patients.

INTRODUCTION: The aim of this study was to investigate the relationship between occlusal contacts, overbite, transverse expansion, and the buccolingual inclination of the teeth with reference to the predicted treatment outcomes and achieved outcomes related to the use of the Invisalign® appliance in mild-to-moderate Class I malocclusions. MATERIAL AND METHODS: The occlusal contacts, overbite, the buccolingual inclination and transverse expansion of the maxillary arch of adult patients satisfying inclusion and exclusion criteria were measured at the initial (pre-treatment), predicted, and achieved treatment stages using metrology software. Pearson correlation coefficients and regression equations were calculated to determine the association between the initial, predicted and achieved changes in occlusal contact against the other variables. RESULTS: Thirty-three patients, who commenced treatment between 2013 and 2018 and satisfied inclusion/exclusion criteria were evaluated. An overall loss of posterior contact was recorded and highlighted by a significantly greater loss of contact from the maxillary buccal occlusal surfaces compared to the palatal occlusal surfaces. The mean [SD] achieved overbite outcome (2.94mm [1.17]) was greater than the predicted (1.74mm [0.87), P<0.001). The buccolingual inclination was significantly increased for the lateral incisors and first and second molars despite a predicted decrease (P≤0.007). Achieved transverse expansion showed significant variation from the predicted. The loss of posterior occlusal contact was correlated with the buccolingual inclination (r=0.70) and transverse expansion (r=0.74) of the posterior teeth. CONCLUSIONS: In mild-to-moderate Class I malocclusions, treatment using the Invisalign® appliance resulted in an overall loss of posterior contact. The loss of occlusal contact was correlated with deficiencies in achieved buccolingual inclination and transverse expansion of the posterior teeth. Planned bodily expansion was ineffective as most expansion occurred due to unplanned buccal tipping.

Assessment of orthodontic treatment needs in patients with ß-thalassemia major and sickle cell disease.

Patients suffering from hemoglobinopathies may suffer from pathogic dental and orofacial features. This study aimed to assess the prevalence of malocclusion and the need for orthodontic treatment in patients with ß-thalassemia major (BTM) and sickle cell disease (SCD). The study was conducted on 311 blood transfusion-dependent patients with BTM or SCD and 400 healthy individuals aged 10 to 16. The types of malocclusion were evaluated based on Angle's classification and Dewey's modification, and their oral habits were recorded using a questionnaire. The need for orthodontic treatment was assessed through the Dental Health Component of the Index of Orthodontic Treatment Need (IOTN), and the data were compared with normal participants. The Index of Orthodontic Treatment Need-Dental Health Component (IOTN-DHC) assessment showed that patients had a higher prevalence of objective need for treatment (IOTN grades 4 and 5) compared to healthy children. The prevalence of class II malocclusion was significantly higher in patients. Patients showed significantly less Angle's Class I malocclusion compared to normal participants. Oral habits were presented in 61%, 64.15% and 62.4% of normal participants, BTM and SCD patients, respectively. The higher prevalence of Angle's class II malocclusion and higher percentage of IOTN grade 4 and 5 among BTM and SCD patients reveal the importance of early orthodontic assessment and intervention in children with BMT and SDC.

Morphologic variations in the craniofacial structures in Japanese adults and their relationship with sex differences.

INTRODUCTION: The morphology of the human face varies broadly, with genetic and environmental factors determining these variations. Examining variations in the 3-dimensional (3D) craniomandibular morphology and identifying related factors (eg, sex differences) are important in orthodontic clinics. This study observed shape variations in the 3D facial morphology of Japanese adults showing skeletal Class 1 malocclusion and examined the association of sexual dimorphism with shape variations. METHODS: Sixty cone-beam computed tomography images of Japanese adults (30 males and 30 females) with skeletal Class I malocclusion were employed. In each cone-beam computed tomography image, wire mesh fitting was conducted as previously described. A principal component (PC) analysis after Procrustes registration and the PC clustering method was conducted to observe the shape variations. A PC regression analysis was conducted to determine the sexual morphologic characteristics. RESULTS: Nine PCs depicting 62% of the morphology were determined. Four typical phenotypes were found, mainly related to mandibular protrusion (PC1) and the vertical divergence of the face (PC2). PCs related to sex determination were PC3 (robustness of the mandibular angle in males), PC5 (greater size and shape of the coronoid and mastoid processes in males), and PC7 (greater maxillary width in males), accounting for 16% of total variations. CONCLUSIONS: The major shape variations in skeletal Class 1 subjects were related to nonsexual dimorphic characteristics (ie, mandibular protrusion and facial divergence). Sexual dimorphic characteristics were evaluated in detail and accounted for 16% of total morphologic variations.

Comparative assessment of dental and basal arch dimensions of passive and active self-ligating versus conventional appliances : A randomized clinical trial.

PURPOSE: In this parallel, three-arm, single-center randomized trial, the dental and basal arch dimensions after orthodontic treatment using conventional brackets and passive and active self-ligating (SL) brackets were compared. METHODS: Patients needing comprehensive orthodontic treatment were randomly allocated to the active SL, passive SL, or conventional brackets (control) group. All patients were treated with a standardized arch wires sequence. Eligibility criteria included class I malocclusion in the permanent dentition, crowding (4-6 mm), and adequate oral hygiene. The primary outcome was intermolar width, based on cone beam computed tomography (CBCT) scans. Secondary outcomes were maxillary and mandibular widths in the canines and premolars regions, dental arch depth, buccolingual inclination, and alignment duration. Blinding of outcome assessment was implemented. Patients were followed every 4 weeks until insertion of the stainless steel 0.019â€¯× 0.025 wire. Mean values were computed from CBCT sections, and data were analyzed using a one-way analysis of variance. RESULTS: In all, 66 patients (ages 18-25 years) were randomized into a 1:1:1 ratio; 7 patients dropped out before treatment initiation. Examining dental arch dimensions in the canine and premolar regions showed that expansion of the maxillary dental arch was greatest in the passive SL brackets group, less in the active SL brackets group, and lowest in the control group (P < 0.01). Changes in maxillary intermolar width between the three groups were not significant, and changes in basal arch dimensions, depth of dental and basal arches, buccolingual inclination, and alignment duration were similar in the three groups. CONCLUSIONS: Self-ligating brackets were not more effective than conventional brackets when examining intermolar width, basal transverse dimensions, depth of the arch, and alignment duration.

Dentoskeletal and soft tissue changes after treatment of crowding with premolar extractions: a 50-year follow-up.

BACKGROUND: The long-term effects on dentofacial morphology of interceptive treatment with premolar extractions, in the absence of subsequent orthodontic treatment, have not been fully explored. OBJECTIVE: The aim was to investigate the effects of premolar extractions (without subsequent orthodontic treatment) on the dentoskeletal and soft tissue profile of patients aged between 12 and 62 years with Class I malocclusion with severe crowding, as compared to untreated controls. MATERIALS AND METHODS: The Extraction group (N = 30 with Class I crowding malocclusion) had their first premolars removed in early adolescence without subsequent orthodontic treatment. The Control group included 30 untreated subjects with Class I normal occlusion. Cephalograms were taken at 12 (T1), 15 (T2), 30 (T3), and 62 (T4) years of age. A superimposition-based cephalometric method was used to assess the dentoskeletal and soft tissue changes. RESULTS: There were no significant differences between the Extraction and Control groups in terms of skeletal sagittal relation, incisor inclination, and protrusion, or most of the soft tissue parameters throughout the observation period. However, significant differences were observed between the groups with respect to the vertical relations in T2-T3, such that the Extraction group showed more-pronounced decreases in the ML/NSL, ML/NL, and Gonial angles and more-pronounced increases in facial heights. CONCLUSIONS AND IMPLICATIONS: Treatment for subjects with Class I malocclusion with severe crowding by the extraction of four premolars, without subsequent orthodontic treatment, does not affect the long-term dentoskeletal and soft tissue profile, as compared to an untreated Control group. The degree of crowding, rather than changes in dentofacial morphology, is crucial in deciding on extraction therapy.

Skeletal and soft-tissue changes in humans with untreated normal occlusion throughout lifetime: a systematic review.

Age-related skeletal and soft-tissue changes are important in orthodontics, especially due to the increase of adult patients seeking treatment. The aim of this study is to assess the available evidence regarding age-related skeletal and soft-tissue changes in untreated Angle Class I. Articles studying skeletal and soft-tissue changes in orthodontically untreated subjects with Angle Class I and comparing them between age groups were included. Studies focusing on a single age group or in languages other than English were excluded. Risk of bias was assessed with both the MINORS and ROBINS-I tools. 50 studies were included, showing high methodological heterogeneity and a lack of information in subjects over 60 years old. In subjects with Angle Class I, the mandibular plane inclination was reported to reduce from 7 and 20 years old, while the anterior and posterior facial height continue to increase in late adult life. The anterior cranial base length increases until 20 years old, afterwards decreasing slowly until late adulthood. Nasal width increases and the nasolabial angle decreases during adolescence. Upper lip length and lower lip length increase from 6 to 18 years along with retrusion of the lips in late adulthood. Age-related skeletal and soft-tissue changes are documented in the literature from childhood until the fifth decade of life, but studies mostly focus on subjects until 20 years old. Changes after the second decade of life are studied only for the vertical and sagittal dimensions. No changes are reported in the transversal dimension beyond 15 years for neither skeletal nor soft tissues. Well-designed, long-term prospective cohort studies considering all three dimensions of skeletal and soft tissues are needed for confirmation of these findings (PROSPERO: CRD42020203206).

Prevalence and extent of Alveolar dehiscence and fenestration in Class I hyperdivergent subjects with different buccolingual inclinations of maxillary molar teeth: a CBCT study

Buccolingual position of teeth could affect the prevalence of alveolar bone defects. Presence of alveolar defects may have a deleterious effect on orthodontic treatment. The aim was to assess the prevalence and extent of dehiscence and fenestration in Class I hyperdivergent subjects and correlate it with buccolingual inclinations(BL) of maxillary first molar teeth. Methods: This retrospective study involved 80 CBCTs of class I hyperdivergent subjects divided into two groups - group A (n=33) buccolingual inclination >9º and group B (n=47) buccolingual inclination <9º. Prevalence and extent of alveolar bone dehiscence and fenestrations were measured in CBCTs using OSIRIX Lite software. Descriptive statistics, Mann Whitney U test and Spearman correlation were done for evaluating intergroup differences and correlation with Buccolingual inclination. Results: Overall prevalence of dehiscence and fenestration in maxillary first molars was 60.95% and 5% respectively. In the buccal alveolar bone, prevalence of dehiscence was highest in group A (84.6%) for 16 and in the lingual alveolar bone prevalence of dehiscence was highest in group B (71.4%) for 26 . On intergroup comparison, the extent of lingual alveolar bone dehiscence (26) in group B was significantly higher (p value <0.05) than in group A. No significant correlation between the extent of dehiscence and fenestration with buccolingual inclination of molar teeth was noted. Conclusion: Molar teeth with BL inclinations of more than 9º had higher prevalence of dehiscence on the buccal side and molar teeth with BL inclinations less than 9 degrees had more dehiscence on the lingual side. But no significant correlation of BL inclination with prevalence and extent of dehiscence and fenestration was noted