Asymmetry in Class II subdivision malocclusion: Assessment based on 3D surface models.

INTRODUCTION: There is currently no consensus in the literature whether the aetiology of a Class II subdivision is dental, skeletal or both. The aim of this study was to identify and quantify skeletal and dental asymmetries in Class II subdivision malocclusions. METHODS: CBCTs from 33 Class II subdivision malocclusion patients were used to construct 3D volumetric label maps. Eighteen landmarks were identified. The original scan and associated 3D volumetric label map were mirrored. Registration of the original and mirrored images relative to the anterior cranial base, maxilla and mandible were performed. Surface models were generated, and 3D differences were quantified. Statistical analysis was performed. RESULTS: Anterior cranial base registration showed significant differences for fossa vertical difference, fossa roll, mandibular yaw, mandibular lateral displacement and lower midline displacement. Regional registrations showed significant differences for antero-posterior (A-P) mandibular length, maxillary roll, A-P maxillary first molar position, maxillary first molar yaw and maxillary first molar roll. Class II subdivision patients also show an asymmetric mandibular length as well as an asymmetric gonial angle. Moderate correlations were found between the A-P molar relationship and fossa A-P difference, mandibular first molar A-P difference, maxillary first molar A-P difference and maxillary first molar yaw. CONCLUSIONS: This study suggests that Class II subdivisions can result from both significant skeletal and dental factors. Skeletal factors include a shorter mandible as well as posterior and higher displacement of the fossa on the Class II side, resulting in mandibular yaw. Dental factors include maxillary and mandibular first molar antero-posterior asymmetry.

3D analysis of maxillomandibular morphology in hyperdivergent and hypodivergent individuals: A cross-sectional study.

INTRODUCTION: The aim of this cross-sectional study was to investigate maxillomandibular morphology in hyperdivergent and hypodivergent individuals, using 3D surface models generated by cone-beam computed tomography (CBCT). METHODS: The sample consisted of 60 CBCTs (30 males, 30 females) patients aged 12-30 years, divided into two groups comprising hyperdivergent (≥35°) and hypodivergent (≤30°) individuals, according to the mandibular plane (MP) angle. Multiplanar reconstructions were used to mark the landmarks, and 3D surface models were created to evaluate structures of the maxillomandibular complex, including condyle, ramus, symphysis and palatal height. Intergroup comparisons were performed by independent t-test. Pearson's correlation test was used (P < .05) to evaluate the correlation of the MP angle with the angles and linear measurements of other structures. RESULTS: Significant differences were found between the groups regarding condylar width, ramus height, condylar plus ramus height, mandibular length, gonial angle, palatal plane angle and palatal-mandibular angle. No differences (P > .05) were found for the condylar height, symphysis inclination angle or palatal height. Correlations (P < .05) were found between the MP angle and structures of the maxillomandibular complex. CONCLUSIONS: Hyperdivergent (MP ≥ 35°) and hypodivergent (MP ≤ 30°) individuals present different skeletal morphology regarding condylar width, ramus height, condylar plus ramus height, mandibular length, gonial angle, palatal plane angle and palatal-mandibular angle. There is a significant correlation between MP angle and morphological structures such as condyle, ramus, symphysis, palatal plane angle and palatal-mandibular angle.

Effect of an aqueous 4% titanium tetrafluoride solution on preventing caries in orthodontic patients: a controlled clinical trial.

INTRODUCTION: Titanium tetrafluoride (TiF4) is a fluoride compound that, when is applied over enamel, promotes a protection against demineralization through a titanium dioxide (TiO2) acid-resistant coat. OBJECTIVES: This study sought to verify the hypothesis that a single application of 4% TiF4 increases the resistance of enamel to dental demineralization in orthodontic patients. MATERIALS AND METHODS: This controlled clinical trial followed CONSORT guidelines and investigated the prevention of enamel demineralization, fluoride retention, and the presence of a Ti layer after TiF4 application on banded teeth exposed to clinical cariogenic biofilm. Forty premolars were divided into a control group (CG; n = 20) and a test group (TG; n = 20). Teeth from both groups received prophylaxis and orthodontic bands with a cariogenic locus. In the TG, all teeth additionally underwent aqueous 4% TiF4 solution application after prophylaxis before being banded. After one month, teeth from both groups were extracted and prepared to assess the microhardness, fluoride retention, and evaluation of the Ti coating over the enamel surface. All data were analyzed with a paired Student's t-test (p<0.05). RESULTS: Enamel microhardness and fluoride uptake were higher in TG than in CG, while the Ti layer could be seen over TG teeth that received TiF4 application. CONCLUSION: Under clinical circumstances, the 4% aqueous TiF4 solution was effective in preventing enamel mineral loss through increasing the enamel resistance to dental demineralization, enhancing its microhardness and fluoride uptake, and forming a Ti coat.

Cone-beam computed tomography study of mandibular morphology and tooth compensation in asymmetrical patients.

INTRODUCTION: This study evaluated mandibular morphology and transverse dental compensation between symmetrical and asymmetrical subjects, allocated according to sagittal skeletal patterns. In addition, the hypothesis that mandibular morphology and dental compensations differed between symmetrical/asymmetrical groups and also among the different types of sagittal skeletal patterns was tested. METHODS: Cone-beam computed tomography images of 96 patients were included in this study and were divided into 2 groups according to the degree of menton deviation: a symmetrical group with deviation up to 2.0 mm (n = 48; mean age, 15 ± 6 years), and an asymmetrical group with deviation from 3.5 mm (n = 48; mean age, 16 ± 8 years). The 2 groups were divided in accordance with the ANB angle: Class I, II, and III. Skeletal and dental measurements were performed. Intergroup and intragroup analyses were carried out, using a 2-way analysis of variance to assess the interaction of factors: symmetry and sagittal skeletal pattern; and the Student t test for differences between deviated (Dv) and nondeviated (NDv) sides. RESULTS: Symmetrical/asymmetrical groups and Class I, II, and III groups were similar in relation to demographic aspects (P = 0.412 and P = 0.357 for sex and age, respectively). Asymmetrical patients had higher values for body length and mandibular ramus and condyle height on the NDv side (P = 0.011, P = 0.024, and P = 0.001, respectively). When comparing the different skeletal patterns, patients with a Class III relationship demonstrated higher values for mandibular ramus height. Intergroup analysis showed no differences in dental parameters. In the comparison between the sides, the asymmetrical group showed a significant difference in canine inclination (P = 0.008), mandibular ramus height (P = 0.004), condyle height (P = 0.010) and gonion to midsagittal plane distance (P = 0.018). CONCLUSIONS: Asymmetrical subjects showed higher values for canine inclination and mandibular body, ramus and condylar height on the NDv side. The hypothesis was partially confirmed that mandibular morphology and dental compensations are different between symmetrical/asymmetrical groups and among different sagittal skeletal patterns.

Effect of an aqueous 4% titanium tetrafluoride solution on preventing caries in orthodontic patients: a controlled clinical trial

ABSTRACT Introduction: Titanium tetrafluoride (TiF4) is a fluoride compound that, when is applied over enamel, promotes a protection against demineralization through a titanium dioxide (TiO2) acid-resistant coat. Objectives: This study sought to verify the hypothesis that a single application of 4% TiF4 increases the resistance of enamel to dental demineralization in orthodontic patients. Materials and Methods: This controlled clinical trial followed CONSORT guidelines and investigated the prevention of enamel demineralization, fluoride retention, and the presence of a Ti layer after TiF4 application on banded teeth exposed to clinical cariogenic biofilm. Forty premolars were divided into a control group (CG; n = 20) and a test group (TG; n = 20). Teeth from both groups received prophylaxis and orthodontic bands with a cariogenic locus. In the TG, all teeth additionally underwent aqueous 4% TiF4 solution application after prophylaxis before being banded. After one month, teeth from both groups were extracted and prepared to assess the microhardness, fluoride retention, and evaluation of the Ti coating over the enamel surface. All data were analyzed with a paired Student's t-test (p<0.05). Results: Enamel microhardness and fluoride uptake were higher in TG than in CG, while the Ti layer could be seen over TG teeth that received TiF4 application. Conclusion: Under clinical circumstances, the 4% aqueous TiF4 solution was effective in preventing enamel mineral loss through increasing the enamel resistance to dental demineralization, enhancing its microhardness and fluoride uptake, and forming a Ti coat.

RESUMO Introdução: O tetrafluoreto de titânio (TiF4) é um composto fluoretado que, quando aplicado sobre o esmalte dentário, promove uma proteção contra desmineralização, por meio da formação de uma camada ácido-resistente de dióxido de titânio (TiO2). Objetivos: O presente estudo buscou verificar a hipótese de que uma única aplicação de TiF4 a 4% aumenta a resistência do esmalte dentário à desmineralização, em pacientes ortodônticos. Material e Métodos: Esse ensaio clínico controlado seguiu as diretrizes do CONSORT e investigou a prevenção da desmineralização do esmalte, retenção de flúor e a presença de uma camada de titânio após a aplicação do TiF4 em dentes bandados expostos ao biofilme cariogênico clínico. Quarenta pré-molares foram divididos em dois grupos: controle (GC; n = 20) e teste (GT; n = 20). Dentes de ambos os grupos receberam profilaxia e bandas ortodônticas com nicho cariogênico. No GT, todos os dentes também foram submetidos a aplicação de solução aquosa de TiF4 4 após profilaxia, antes de serem bandados. Após um mês, os dentes de ambos os grupos foram extraídos e preparados para avaliar a microdureza, retenção de flúor e avaliação da camada de titânio sobre a superfície do esmalte. Todos os dados foram analisados pelo teste t pareado (p<0,05). Resultados: A microdureza do esmalte e a absorção de flúor foram mais elevadas no GT do que no GC, enquanto uma camada de titânio pôde ser observada sobre os dentes do GT, que receberam aplicação TiF4. Conclusão: Em circunstâncias clínicas, a solução de TiF4 a 4% foi eficaz na prevenção da perda mineral do esmalte, por meio do aumento da resistência à desmineralização dentária, aumentando sua microdureza e absorção de flúor, e formando uma camada protetora de titânio.

Presurgical orthodontic decompensation with clear aligners.

INTRODUCTION: Orthodontists, surgeons, and patients have taken an interest in using clear aligners in combination with orthognathic surgery. This study aimed to evaluate the accuracy of tooth movements with clear aligners during presurgical orthodontics using novel 3-dimensional superimposition techniques. METHODS: The study sample consisted of 20 patients who have completed presurgical orthodontics using Invisalign clear aligners. Initial (pretreatment) digital dental models, presurgical digital dental models, and ClinCheck prediction models were obtained. Presurgical models were superimposed onto initial ones using stable anatomic landmarks; ClinCheck models were superimposed onto presurgical models using surface best-fit superimposition. Five hundred forty-five teeth were measured for 3 angular movements (buccolingual torque, mesiodistal tip, and rotation) and 4 linear movements (buccolingual, mesiodistal, vertical, and total scalar displacement). The predicted tooth movement was compared with the achieved amount for each movement and tooth, using both percentage accuracy and numerical difference. RESULTS: Average percentage accuracy (63.4% ± 11.5%) was higher than in previously reported literature. The most accurate tooth movements were buccal torque and mesial displacement compared with lingual torque and distal displacement, particularly for mandibular posterior teeth. Clinically significant inaccuracies were found for the buccal displacement of maxillary second molars, lingual displacement of all molars, intrusion of mandibular second molars, the distal tip of molars, second premolars, and mandibular first premolars, buccal torque of maxillary central and lateral incisors, and lingual torque of premolars and molars. CONCLUSIONS: Superimposition techniques used in this study lay the groundwork for future studies to analyze advanced clear aligner patients. Invisalign is a treatment modality that can be considered for presurgical orthodontics-tooth movements involved in arch leveling and decompensation are highly accurate when comparing the simulated and the clinically achieved movements.

Dental long axes using digital dental models compared to cone-beam computed tomography.

OBJECTIVE: Standard methods of evaluating tooth long axes are not comparable (digital dental models [DDMs], panoramic and cephalometric radiographs) or expose patients to more radiation (cone-beam computed tomography [CBCT]). This study aimed to compare angular changes in tooth long axes using DDMs vs using CBCTs. SETTINGS AND SAMPLE POPULATION: Secondary data analysis of DDMs and CBCTs, taken before and after orthodontic treatment with piezocision of 24 patients. METHODS: Angular changes in tooth long axes were evaluated using landmarks on first molars (centre of the occlusal surface and centre of the furcation), canines and incisors (cusp tip and centre of the root at the cementoenamel junction). Wilcoxon test, intraclass correlation coefficient (ICC) and Bland-Altman plots were used to test intra- and inter-rater agreement and compare DDM and CBCT measurements. RESULTS: The mesiodistal angulation and buccolingual inclination DDM measurements were reproducible. Overall mean differences between DDM and CBCT measurements of mesiodistal angulation, 1.9°±1.5°, and buccolingual inclination, 2.2 ± 2.2°, were not significant for all teeth. ICC between DDM and CBCT measurements ranged from good (0.85 molars) to excellent (0.94 canines; 0.96 incisors). The percentages of measurements outside the range of ±5 were 17.4% for molars, 13.8% for canines and 4.5% for incisors. CONCLUSIONS: DDM assessment of changes in tooth long axes has good reproducibility and yields comparable measurements to those obtained from CBCT within a 5° range. These findings lay the groundwork for machine learning approaches that synthesize crown and root canal information towards planning tooth movement without the need for ionizing radiation scans.

Quantification of three-dimensional morphology of craniofacial mineralized tissue defects in Tgfbr2/Osx-Cre mice.

Craniofacial morphology is affected by the growth, development, and three-dimensional (3D) relationship of mineralized structures including the skull, jaws, and teeth. Despite fulfilling different purposes within this region, cranial bones and tooth dentin are derived from mesenchymal cells that are affected by perturbations within the TGF-ß signaling pathway. TGFBR2 encodes a transmembrane receptor that is part of the canonical, SMAD-dependent TGF-ß signaling pathway and mutations within this gene are associated with Loeys-Dietz syndrome, a condition which often presents with craniofacial signs including craniosynostosis and cleft palate. To investigate the role of Tgfbr2 in immature, but committed, mineralized tissue forming cells, we analyzed postnatal craniofacial morphology in mice with conditional Tgfbr2 deletion in Osx-expressing cells. Novel application of a 3D shape-based comparative technique revealed that Tgfbr2 in Osx-expressing cells results in impaired postnatal molar root and anterior cranial growth. These findings support those from studies using similar Tgfbr2 conditional knockout models, highlight the anomalous facial and dental regions/structures using tomographic imaging-based techniques, and provide insight into the role of Tgfbr2 during postnatal craniofacial development.

Mandibular condylar remodeling characteristics after simultaneous condylectomy and orthognathic surgery.

INTRODUCTION: The objectives of this study were to evaluate postsurgical condylar remodeling using a radiographical interpretation, quantify condylar volumetric asymmetry, and assess soft tissue symmetry after simultaneous unilateral high condylectomy and bimaxillary osteotomies. METHODS: Sixteen patients diagnosed with unilateral condylar hyperplasia underwent unilateral high condylectomy and orthognathic surgery to correct skeletal and facial asymmetries. Cone-beam computed tomography scans were acquired before and 1-year after surgery. A radiographic consensus was evaluated for signs of reparative or degenerative changes. The condyles were mirrored and registered for assessment of volumetric and morphologic asymmetry. Soft tissue symmetry was evaluated by measurement of the distance of soft tissue pogonion from the skeletal midsagittal plane. RESULTS: Patients who undergo unilateral high condylectomy and orthognathic surgery present radiographic signs suggestive of degenerative changes, including sclerosis, osteophytes, flattening, and erosion in both the surgical and nonsurgical condyles (P ≤0.01). There was an average volumetric improvement of 531.9 ± 662.3 mm3 1-year postsurgery (P = 0.006). Soft tissue symmetry improved in all patients, with an average improvement of 65.8% (4.0 mm ± 2.6 mm, P ≤ 0.01). There was no correlation between the change in condylar volumetric asymmetry and the stability of the soft tissue correction. CONCLUSIONS: High condylectomy for the correction of a skeletal asymmetry in patients with condylar hyperplasia successfully reduces the volumetric asymmetry between the condyles. Postsurgical dysmorphic remodeling and degenerative changes were noted in both the surgical and nonsurgical condyles. Despite remarkable changes and remaining joint asymmetry, the soft tissue correction is stable 1-year postsurgery.

Tomographic analysis of midpalatal suture prior to rapid maxillary expansion.

INTRODUCTION: In Orthodontics and Facial Orthopedics, the timing of treatment onset may be critical and individual analysis should be applied to promote a favorable treatment planning. In this study, individual analysis of midpalatal suture (MS) and palatal measurements were performed in teenagers and young adult patients treated with rapid maxillary expansion (RME). DESCRIPTION: Twenty-six patients submitted to RME with a tooth-supported appliance (Hyrax) were evaluated. The inclusion criteria were: minimum age of 14 years, presenting all posterior teeth, diagnosed with transverse maxillary discrepancy, and with a clinical indication for maxillary expansion. The pretreatment CBCT scans of these patients were assessed to obtain the stages of MS maturation (MSM); density ratio (MSD); and palatal length, thickness (anterior, intermediate and posterior) and sagittal area. RESULTS: The maturation stages present were C, D or E; the density ranged from 0.6 to 1, and lower density (MSD < 0.75) and higher density (MSD ≥ 0.75) groups were determined. Individuals with higher MSD presented smaller sagittal area, compared to the lower density group. Individuals in D and E MSM stages presented smaller sagittal area and intermediate thickness, compared to stage C. CONCLUSIONS: Smaller palatal sagittal area was observed in the high MSD groups and in the stages D and E of MSM.

Directions of mandibular canal displacement in ameloblastoma: A computed tomography mirrored-method analysis.

PURPOSE: This study was performed to investigate mandibular canal displacement in patients with ameloblastoma using a 3-dimensional mirrored-model analysis. MATERIALS AND METHODS: The sample consisted of computed tomographic scans of patients with ameloblastoma (n=10) and healthy controls (n=20). The amount of mandibular canal asymmetry was recorded as a continuous variable, while the buccolingual (yaw) and supero-inferior (pitch) directions of displacement were classified as categorical variables. The t-test for independent samples and the Fisher exact test were used to compare groups in terms of differences between sides and the presence of asymmetric inclinations, respectively (P<0.05). RESULTS: The length of the mandibular canal was similar on both sides in both groups. The ameloblastoma group presented more lateral (2.40±4.16 mm) and inferior (-1.97±1.92 mm) positions of the mental foramen, and a more buccal (1.09±2.75 mm) position of the middle canal point on the lesion side. Displacement of the mandibular canal tended to be found in the anterior region in patients with ameloblastoma, occurring toward the buccal and inferior directions in 60% and 70% of ameloblastoma patients, respectively. CONCLUSION: Mandibular canal displacement due to ameloblastoma could be detected by this superimposed mirrored method, and displacement was more prevalent toward the inferior and buccal directions. This displacement affected the mental foramen position, but did not lead to a change in the length of the mandibular canal. The control group presented no mandibular canal displacement.

Three-dimensional evaluation of dental decompensation and mandibular symphysis remodeling on orthodontic-surgical treatment of Class III malocclusion.

INTRODUCTION: The purposes of this research were to identify the buccolingual inclinations of the mandibular teeth and the mandibular symphysis remodeling that result from the orthodontic decompensation movement. METHODS: The sample consisted of 30 adults with Class III dentofacial deformity, who had presurgical orthodontic treatment. Three-dimensional images were generated by cone-beam computed tomography scans at 2 different times (initial and before orthognathic surgery). Three-dimensional virtual models were obtained and superimposed using automated voxel-based registration at the mandible to evaluate B-point displacement, mandibular molar and incisor decompensation movement, and symphysis inclination and thickness. The 3-dimensional displacements of landmarks at the symphysis were quantified and visualized with color-coded maps using 3D Slicer (version 4.0; www.slicer.org) software. RESULTS: The measurements showed high reproducibility. The patients presented mandibular incisor proclination, which was consistent with the movement of tooth decompensation caused by the presurgical orthodontic treatment. Statistically significant correlations were found between the inclination of the mandibular incisors, symphysis inclination, and B-point displacement. Regarding the thickness of the symphysis and the inclination of the incisors, no statistically significant correlation was found. CONCLUSIONS: The buccolingual orthodontic movement of the mandibular incisors with presurgical leveling is correlated with the inclination of the mandibular symphysis and repositioning of the B-point but not correlated to the thickness of the symphysis.

Three-dimensional mandibular dental changes with aging.

INTRODUCTION: This study aimed to evaluate the 3-dimensional (3D) mandibular dental changes over 42 years using the registration of digital models. METHODS: The sample comprised digital dental models of 8 untreated subjects (4 males and 4 females) with normal occlusion measured longitudinally at ages 17 years (T1) and 60 years (T2). Using 13 landmarks placed on the mucogingival junction, we registered the T2 model on the T1 model. Three-dimensional changes in the position of the landmarks on the buccal cusp tip of the posterior teeth and incisal edge of the central incisors were measured by 2 examiners. Registration and measurements were performed using SlicerCMF (version 3.1; http://www.slicer.org) software. Intra- and interrater agreements were evaluated using intraclass correlation coefficients and the Bland-Altman method. One-sample t tests were used for evaluating interphase 3D dental changes (P <0.05). RESULTS: Adequate intra- and interrater reproducibility was found. From T1 to T2, the mandibular teeth showed significant 3D positional changes. A significant dental eruption relative to the mucogingival junction was observed for the anterior and posterior teeth. Anteroposterior movements of mandibular teeth were not significant except for the right molar that drifted mesially. Transverse movements included slight lingual tipping at canines and premolars regions. CONCLUSIONS: Dental changes in untreated normal occlusion were very slight from early to mature adulthood. The eruption of the mandibular teeth was the most consistent finding. A tendency for mesial movement of molars and lingual movement of first premolars and canines was observed in the mandible during the aging process.

Are temporomandibular disorders associated with facial asymmetry? A systematic review and meta-analysis.

OBJECTIVE: To assess scientific evidence of the association between temporomandibular joint (TMJ) disorders and facial asymmetry (FA). METHODS: A systematic review was performed in accordance with the PRISMA checklist. A search strategy was developed in electronic databases including MEDLINE, Scopus, Web of Science, Virtual Health Library and Cochrane Library until January 2020. Eligibility criteria included observational studies that investigated the occurrence of FA among patients with and without signs and symptoms of TMJ disorders. Risk of bias of individual studies was analysed after study selection and data collection processes according to Fowkes and Fulton guidelines. Four meta-analyses (MA) were performed to evaluate the association between TMJ disorders and linear/angular menton deviation, subgrouping the studies into unilateral and bilateral cases. The evidence was certainty-tested using the GRADE approach. RESULTS: The search retrieved 2371 studies, 31 of which were eligible for full-text reading. Seven cross-sectional clinical studies met the eligibility criteria and were included in the qualitative synthesis, comprising a total of 621 subjects (345 with TMJ disease and 276 in control group), four of which were classified as being methodologically sound. Five studies were eligible for quantitative synthesis. Linear and angular menton deviation was greater in individuals with unilateral TMJ disorders than controls (MD = 2.41 [0.33, 4.50] P = .02; I2  = 86% and MD = 2.68 [0.99, 4.38] P = .002; I2  = 0%, respectively). CONCLUSIONS: Despite the low certainty in evidence, the present study indicated that unilateral TMJ disorders are associated with FA. However, longitudinal studies with greater certainty of evidence should be conducted to achieve a stronger estimate of this association.

Tomographic analysis of midpalatal suture prior to rapid maxillary expansion

ABSTRACT Introduction: In Orthodontics and Facial Orthopedics, the timing of treatment onset may be critical and individual analysis should be applied to promote a favorable treatment planning. In this study, individual analysis of midpalatal suture (MS) and palatal measurements were performed in teenagers and young adult patients treated with rapid maxillary expansion (RME). Description: Twenty-six patients submitted to RME with a tooth-supported appliance (Hyrax) were evaluated. The inclusion criteria were: minimum age of 14 years, presenting all posterior teeth, diagnosed with transverse maxillary discrepancy, and with a clinical indication for maxillary expansion. The pretreatment CBCT scans of these patients were assessed to obtain the stages of MS maturation (MSM); density ratio (MSD); and palatal length, thickness (anterior, intermediate and posterior) and sagittal area. Results: The maturation stages present were C, D or E; the density ranged from 0.6 to 1, and lower density (MSD < 0.75) and higher density (MSD ≥ 0.75) groups were determined. Individuals with higher MSD presented smaller sagittal area, compared to the lower density group. Individuals in D and E MSM stages presented smaller sagittal area and intermediate thickness, compared to stage C. Conclusions: Smaller palatal sagittal area was observed in the high MSD groups and in the stages D and E of MSM.

RESUMO Introdução: Em Ortodontia e Ortopedia Facial, o momento de início do tratamento pode ser crítico, e uma análise individual deve ser aplicada para promover um planejamento de tratamento favorável. No presente estudo, foram realizadas a avaliação individualizada da sutura palatina mediana (SPM) e medições no palato de adolescentes e adultos jovens tratados com expansão rápida da maxila (ERM). Descrição: Foram avaliados vinte e seis pacientes submetidos à ERM com aparelho dentossuportado (Hyrax). Os critérios de inclusão foram: idade mínima de 14 anos, apresentando todos os dentes posteriores, diagnosticado com discrepância transversa da maxila e com uma indicação clínica para expansão maxilar. A tomografia computadorizada de feixe cônico (TCFC) pré-tratamento desses pacientes foi avaliada para obter os estágios de maturação da SPM (MSPM), densidade da SPM (DSPM), comprimento do palato, espessura (anterior, intermediária e posterior) e área sagital. Resultados: Os estágios de maturação presentes foram C, D ou E; a densidade variou de 0,6 a 1, e foram determinados grupos de baixa (DSPM < 0,75) e alta densidade (DSPM ≥ 0,75). Indivíduos com maior DSPM apresentaram menor área sagital, em comparação com o grupo de densidade mais baixa. Indivíduos nos estágios D e E de MSPM apresentaram menor área sagital e espessura intermediária, comparados aos indivíduos no estágio C. Conclusão: Uma menor área sagital palatina foi observada nos grupos de alta DSPM e nos estágios D e E de MSPM.

Three-dimensional assessment of craniofacial asymmetry in children with transverse maxillary deficiency after rapid maxillary expansion: A prospective study.

OBJECTIVE: The aim of this study was to evaluate craniofacial asymmetry in children with transverse maxillary deficiency, with or without functional unilateral posterior crossbite (UPC), before and after rapid maxillary expansion (RME). SETTING AND SAMPLE POPULATION: A sample of 51 children with cone beam computed tomography scans obtained before RME (T1) and a year after RME (T2). MATERIAL AND METHODS: This prospective study consisted of 2 groups: 25 children with functional UPC (6.77 ± 1.5 years) and 26 children without UPC (7.41 ± 1.31 years). Linear and angular measurements were obtained from zygomatic, maxilla, glenoid fossa and mandible, using original and mirrored 3D overlapped models. All right and left side comparisons in both groups and intergroups asymmetries were compared using MANOVA and t test for independent samples, respectively, statistically significant at P < .05. RESULTS: The UPC group showed no side differences, but mandibular horizontal rotation at T1, and this asymmetry was improved in T2. The non-UPC group showed at baseline significant lateral asymmetry in orbitale, position of palatine foramen, respectively, in average 2.95 mm and 1.16 mm, and 0.49 mm of average asymmetry in condylar height. The glenoid fossa was symmetric in both groups at T1 and T2. CONCLUSIONS: Children with transverse maxillary deficiency showed slight morphological asymmetry, located in the mandible position in cases of UPC, and in the orbital and maxillary regions in cases without UPC. One year after RME, patients improved their craniofacial asymmetry, with significant changes in the mandible and correction of the mandibular rotation in patients who presented UPC.

Measurement error and reliability of three available 3D superimposition methods in growing patients.

INTRODUCTION: Cone-Beam Computed Tomography (CBCT) images can be superimposed, allowing three-dimensional (3D) evaluation of craniofacial growth/treatment effects. Limitations of 3D superimposition techniques are related to imaging quality, software/hardware performance, reference areas chosen, and landmark points/volumes identification errors. The aims of this research are to determine/compare the intra-rater reliability generated by three 3D superimposition methods using CBCT images, and compare the changes observed in treated cases by these methods. METHODS: Thirty-six growing individuals (11-14 years old) were selected from patients that received orthodontic treatment. Before and after treatment (average 24 months apart) CBCTs were analyzed using three superimposition methods. The superimposed scans with the two voxel-based methods were used to construct surface models and quantify differences using SlicerCMF software, while distances in the landmark-derived method were calculated using Excel. 3D linear measurements of the models superimposed with each method were then compared. RESULTS: Repeated measurements with each method separately presented good to excellent intraclass correlation coefficient (ICC ≥ 0.825). ICC values were the lowest when comparing the landmark-based method and both voxel-based methods. Moderate to excellent agreement was observed when comparing the voxel-based methods against each other. The landmark-based method generated the highest measurement error. CONCLUSIONS: Findings indicate good to excellent intra-examiner reliability of the three 3D superimposition methods when assessed individually. However, when assessing reliability among the three methods, ICC demonstrated less powerful agreement. The measurements with two of the three methods (CMFreg/Slicer and Dolphin) showed similar mean differences; however, the accuracy of the results could not be determined.

Three-dimensional comparison of the skeletal and dentoalveolar effects of the Herbst and Pendulum appliances followed by fixed appliances: A CBCT study.

OBJECTIVES: To compare three-dimensional (3D) skeletal and dentoalveolar effects of the Herbst and Pendulum appliances followed by fixed orthodontic treatment in growing patients. SETTING AND SAMPLE POPULATION: A sample of 35 adolescents with cone-beam computed tomography scans obtained prior to Herbst and Pendulum treatment (T1) and immediately after fixed appliance treatment (T2). MATERIALS AND METHODS: Patients with Class II malocclusion was assessed retrospectively and divided into two treatment groups: Herbst group (n = 17, age: 12.0 ± 1.6 years) and Pendulum group (n = 18, age: 12.1 ± 1.5 years), with a mean treatment duration of 2.8 ± 0.8 years and 2.5 ± 0.7 years, respectively. Reconstructions of the maxillomandibular and dentoalveolar regions and data in 3D were obtained relative to cranial base, maxillary and mandibular regional superimpositions. Treatment outcomes (T2-T1) were compared between both groups using t tests for independent samples (P<.05). RESULTS: Significant increase in mandibular length was observed in the Herbst group (7.3 ± 3.5 mm) relative to the Pendulum group (4.6 ± 4.5 mm). Inferior and anterior displacements of Pogonion were 2.2 mm and 1.6 mm greater in the Herbst group, respectively. The mesial displacement of the lower first molars was significantly greater in the Herbst group (1.9 mm). The upper first molars had contrasting results in sagittal displacement, with 0.6 ± 1.7 mm of distal displacement with the Pendulum and 1.4 ± 2.1 mm of mesial displacement with the Herbst. Lower incisor projection and proclination were similar between groups. CONCLUSIONS: The Herbst and Pendulum appliances followed by comprehensive orthodontic treatment effectively corrected Class II malocclusion in growing patients, but with differing skeletal and dentoalveolar effects.

Condyle-glenoid fossa relationship after Herbst appliance treatment during two stages of craniofacial skeletal maturation: A retrospective study.

OBJECTIVES: To perform a three-dimensional evaluation of the position of the condyles in patients treated with Herbst appliance (HA) in two stages of cervical vertebral maturation. SETTING AND SAMPLE POPULATION: Retrospective case-control study. Pubertal Herbst group (PHG; n = 24, mean age 14.5 years, CS 3 and CS 4) and pre-pubertal Herbst group (PPHG; n = 17, mean age 9.9 years, CS 1 and CS 2) were contrasted with comparison groups of non-orthopaedically treated Class II patients in pubertal (PCG; n = 17, mean age 13.9 years) and pre-pubertal maturational stages (PPCG; n = 18, mean age 10.6 years). MATERIALS AND METHODS: Cone-beam computer tomography scans were taken before treatment (T0) and at T1 after 8 to 12 months. Point-to-point measurements of the displacement of the condyles between T0 and T1, relative to the glenoid fossae, were performed in the X, Y, Z and 3D perspectives. Qualitative assessments using semi-transparent overlays and colour mapping also were produced. RESULTS: The displacement of the condyles within the glenoid fossae in the treated groups was small (<0.75 mm; P > .05). Relative to the glenoid fossa, condylar position at T1 was similar to T0 in pre-pubertal and pubertal groups (P > .05). Similar condylar rotations from T0 to T1 were observed in Herbst and comparison groups, and no significant difference was found between pre-pubertal and pubertal patients. CONCLUSIONS: Regardless the stage of skeletal maturation, HA treatment did not change the condyle-glenoid fossa relationship.