Evaluation of the three-dimensional (3D) position of cervical vertebrae in individuals with unilateral posterior crossbite.

OBJECTIVE: To evaluate the three-dimensional (3D) position of the cervical vertebrae of growing subjects with unilateral posterior crossbite (UPC). MATERIALS AND METHODS: In this cross-sectional study, cone beam computed tomography (CBCT) scans of 1455 patients were screened, and ultimately 58 scans (26 patients with UPC and 32 controls with normal occlusion) were included after imposing inclusion/exclusion criteria. Roll, yaw, and deviation of the geometric center of C1, C2, and C3 vertebrae were measured and compared between groups. A correlation between these parameters and different variables on mandibular positioning was also carried out. RESULTS: A statistically significant difference (p < 0.05) was observed between groups for the deviation of pogonium (Pog), mandibular plane roll, and C3 roll, and patients with UPC showed higher cant or deviation. A significant correlation was reported for the roll of C2 and C3 with the deviation of Pog, a roll of the occlusal plane, and roll of the mandibular plane (p < 0.05). The greater the deviation of the Pog to one side, the greater the roll of the vertebrae with this same side up. The same tendency was observed between the roll of the occlusal plane or the mandibular plane with the roll of these cervical vertebrae. CONCLUSIONS: There is a positive correlation between transverse occlusal changes and positional deviations of the cervical vertebrae, especially C2 and C3. CLINICAL RELEVANCE: The study results do not allow us to infer the clinical/functional consequences of these deviations, as well as if malocclusion's treatment would result in an improvement of intervertebral relationships.

The effects of corticotomy and piezocision in orthodontic canine retraction: a randomized controlled clinical trial.

BACKGROUND: The aims of this study were to evaluate the efficacy of alveolar corticotomy (AC) and piezocision (PZ) in accelerating maxillary canine retraction, and their effects on multiple bone remodeling expression in gingival crevicular fluid (GCF). A split-mouth, randomized controlled clinical trial was performed at the Department of Orthodontics of Pontifical Catholic University of Minas Gerais, Brazil. Eligibility criteria included orthodontic need for first maxillary premolars extractions, followed by canine retraction. Fifty-one adult patients were recruited and randomly assigned to 3 groups (allocation ratio 1:1:1). Random allocation of surgical or control interventions to each side of the maxillary arch was also conducted: G1 - AC × Control, G2 - PZ × Control, and G3 - AC × PZ. Both the definition of the group and the decision of the experimental or control sides were randomized by the software. Intraoral digital scans were performed before, 7 and 14 days after the beginning of canine retraction, and subsequently, at every 14 days until a maximum period of 6 months. GCF samples were collected before, and 1, 2, 4, 8, and 12 weeks. The primary outcome consisted in the cumulative distal movement of the canines and was measured by digital model superimposition. The secondary outcome consisted in GCF bone remodeling samples that were quantified in a multiplex immunoassay. The measurements examinator was properly blinded. RESULTS: Forty-seven patients, 19 males and 28 females, were analyzed (mean age 20.72, SD = 6.66, range 15 to 38). Statistically significant differences in canine distal movement between AC and control in G1 were not observed (p > 0.05). In G2, PZ showed lower cumulative incisal and cervical measurements than control from the 2nd to the 24th week (p < 0.05). In G3, PZ showed a lower cumulative incisal and cervical measurements than AC from the16th to the 24th week (p < 0.05). In all groups, differences on biomarkers expression occurred at specific timepoints (p < 0.05), but a distinct pattern was not observed. CONCLUSIONS: AC and PZ were not effective to accelerate maxillary canine retraction and did not induce a distinct pattern of biomarker expression. TRIAL REGISTRATION: NCT03089996 . Registered 24 March 2017 - Registered.

Mini Hyrax vs Hyrax expanders in the rapid palatal expansion in adolescents with posterior crossbite: a randomized controlled clinical trial.

PURPOSE: The aim of this study was to compare the dental effects, impact on quality of life, and pain perception of adolescents wearing Mini Hyrax and Hyrax expanders in rapid palatal expansion. METHODS: Thirty-four adolescents aged 11 to 16 years, with maxillary transverse deficiency (unilateral or bilateral posterior crossbite), were randomly allocated into two groups, Mini Hyrax group and Hyrax group (1:1 ratio). Dental effects were evaluated by digitally superimposed pretreatment and postretention three-dimensional intraoral scans on the palatal rugaes using the software 3DSlicer. Impact on quality of life was assessed with the OHIP-14 questionnaire applied in the pretreatment, posttreatment and postretention. Visual analog scale was applied 24, 48, and 72 h and 7 days after the first activation of the expander. RESULTS: Thirty of the 34 adolescents recruited completed the study. There were no statistically significant differences in dentoalveolar effects between groups. OHIP-14 scores across time among Mini Hyrax wearers were similar to those of the Hyrax wearers. The inter-group comparisons showed no difference between groups with respect to the OHIP-14 scores in posttreatment and postretention (p > 0.05). There were no differences in pain perception between groups. Considering intra-group comparison, the reduction in pain perception among adolescents in the Mini Hyrax group was gradual. Among adolescents in the Hyrax group, a statistically significant reduction between 48 and 72 h was observed. CONCLUSION: There were no significant differences in dental effects, impact on quality of life and pain perception between adolescents wearing Mini Hyrax and Hyrax expanders in rapid palatal expansion.

Mandibular ramus height and condyle distance asymmetries in individuals with different facial growth patterns: a cone-beam computed tomography study.

PURPOSE: This study aimed to quantify mandibular ramus height and condylar distances asymmetry indexes in adult patients with different vertical facial growth pattern using Cone Beam computed tomography (CBCT). METHODS: An observational cross-sectional study was conducted by using CBCT of 159 patients (mean age 26.36 ± 5.32 years). Vistadent 3D® software was used to determine the facial pattern in 3 groups (N = 53): hypodivergent, normodivergent and hyperdivergent-by Ricketts VERT index. Mandibular ramus height and the condylar linear distance in relation to the median sagittal plane were evaluated. The asymmetry index was calculated considering the right and left sides. Data were analyzed by generalized linear models and Tukey post-hoc test (α = 0.05). RESULTS: Significantly lower values were found for the left and right mandibular ramus height in the hyperdivergent skeletal pattern (P < 0.05). There was no statistically significant difference for condylar and intercondylar distances among the facial groups (P > 0.05). Asymmetry indexes (mandibular ramus height and condylar distance) were similar, and no statistically significant differences were found among the skeletal patterns. In most subjects, the severity of mandibular ramus height asymmetry varied from light to not clinically significant independently of the facial type. CONCLUSION: The findings suggest that vertical facial growth pattern not affected the asymmetry index of mandibular ramus height and the intercondylar distance. The results also demonstrated significantly shorter mandibular ramus height for the hyperdivergent skeletal pattern individuals.

OrthoAligner "NAM": A Case Series of Presurgical Infant Orthopedics (PSIO) Using Clear Aligners.

Presurgical infant orthopedics (PSIO) is done to reduce the size of the cleft defect along with improving the arch alignment and nasolabial aesthetics in patients with cleft lip and palate, leading to an improvement of nasolabial aesthetics allowing for a tidier and more aesthetic reparative procedure and postsurgical scar. Since the 2000s, clear aligners have slowly and steadily treaded their way as an acceptable orthodontic modality, with their usage and acceptability increasing considerably over the past decade. Thus, from the knowledge gathered in its 10 years working with 3-dimensional (3-D) diagnosis, treatment planning, and 3-D Printing services, Compass 3D (Belo Horizonte, Brazil) developed the OrthoAligner NAM system. This case series highlights one of the world's first documented cases of PSIO treated with a series of clear aligners.

Comparison of the accuracy of virtual and direct bonding of orthodontic accessories.

INTRODUCTION: Conventional direct and indirect bonding techniques fail to obtain the ideal bracket position. OBJECTIVE: To compare the accuracy of virtual and conventional direct bonding of orthodontic accessories. METHODS: A single virtual configuration (dental mannequin with Class I malocclusion) served as basis for generating the reference model (treated virtually) and the intervention models (10 digital models and 10 solid models, obtained by means of prototyping). A total of 560 teeth were then equally distributed between a group of orthodontists (Group I, direct bonding; and Group II, virtual bonding), working in two different time intervals. The individual positions of the accessories were measured after three-dimensional superimposition with customized software. The Student's-t test for paired samples, and Chi-square tests were used for statistical analysis, both at the level of significance of 5%. RESULTS: In comparison of the errors in raw values, there were significant differences only in the vertical (p< 0.001) and horizontal dimensions (p< 0.001). Considering the groups of ranges by clinical limits of the deviations, these differences were significant in the three dimensions, vertical (p< 0.001), horizontal (p= 0.044) and angular (p= 0.044). CONCLUSION: Virtual bonding made it possible to obtain more precise/accurate positioning of the orthodontic accessories. The potential accuracy of this method brings new perspectives to refining the indirect bonding protocols.

Comparison of maxillomandibular asymmetries in adult patients presenting different sagittal jaw relationships.

OBJECTIVE: The present study aims at using cone beam computed tomography (CBCT) to analyze the maxillomandibular characteristics present in adults with mandibular asymmetries and different sagittal jaw relationships. METHODS: 360 patients were selected and divided into three groups (Class I, Class II, and Class III), with 120 individuals per group. The groups were then subdivided according to the intensity of lateral deviation of the gnathion point, into: 1) relative symmetry, 2) moderate asymmetry, and 3) severe asymmetry. Three planes of reference were established in the CBCT images and several measurements were taken to compare the bilateral skeletal differences between the intensities of asymmetry for the different sagittal jaw relationships. RESULTS: When the groups were compared by the intensity of asymmetry, significant differences among patients with relative symmetry and moderate to severe asymmetry were found. This was especially noticed for severe asymmetry, suggesting that the deviation of the chin did not constitute the only morphological alteration for these patients, especially because a series of measurements showed significant bilateral differences. When comparing sagittal jaw relationships, the only significant finding was the vertical positioning of the gonion between Class II and III patients with severe asymmetry. CONCLUSIONS: When comparing the three sagittal jaw relationships with the same intensity of asymmetry, most maxillofacial aspects were quite similar. The only difference was found for patients with severe asymmetry, as the individuals with Class II showed greater bilateral difference in the vertical positioning of the gonion, when compared to patients with Class III.

Comparison of maxillomandibular asymmetries in adult patients presenting different sagittal jaw relationships

ABSTRACT Objective: The present study aims at using cone beam computed tomography (CBCT) to analyze the maxillomandibular characteristics present in adults with mandibular asymmetries and different sagittal jaw relationships. Methods: 360 patients were selected and divided into three groups (Class I, Class II, and Class III), with 120 individuals per group. The groups were then subdivided according to the intensity of lateral deviation of the gnathion point, into: 1) relative symmetry, 2) moderate asymmetry, and 3) severe asymmetry. Three planes of reference were established in the CBCT images and several measurements were taken to compare the bilateral skeletal differences between the intensities of asymmetry for the different sagittal jaw relationships. Results: When the groups were compared by the intensity of asymmetry, significant differences among patients with relative symmetry and moderate to severe asymmetry were found. This was especially noticed for severe asymmetry, suggesting that the deviation of the chin did not constitute the only morphological alteration for these patients, especially because a series of measurements showed significant bilateral differences. When comparing sagittal jaw relationships, the only significant finding was the vertical positioning of the gonion between Class II and III patients with severe asymmetry. Conclusions: When comparing the three sagittal jaw relationships with the same intensity of asymmetry, most maxillofacial aspects were quite similar. The only difference was found for patients with severe asymmetry, as the individuals with Class II showed greater bilateral difference in the vertical positioning of the gonion, when compared to patients with Class III.

RESUMO Objetivo: o presente estudo teve como objetivo analisar, por meio de tomografia computadorizada de feixe cônico (TCFC), as características esqueléticas maxilomandibulares presentes em adultos com diferentes graus de assimetria mandibular e diferentes relações esqueléticas sagitais. Métodos: foram selecionados 360 pacientes, os quais foram divididos em três grupos, com 120 indivíduos cada (Classe I, Classe II e Classe III). Cada grupo foi, ainda, subdividido de acordo com a intensidade do desvio lateral do mento: 1) simetria relativa; 2) assimetria moderada; e 3) assimetria severa. Três planos de referência foram estabelecidos nas imagens de TCFC e várias medidas foram realizadas, sendo comparadas as diferenças esqueléticas bilaterais existentes entre os graus de assimetria em cada grupo, nas diferentes relações esqueléticas sagitais. Resultados: quando comparados os grupos pelos graus de assimetria, existiram diferenças significativas entre pacientes com simetria relativa e pacientes assimétricos, especialmente para a assimetria severa, sugerindo que o desvio do mento não constitui a única alteração morfológica para esses pacientes, especialmente porque uma série de medidas apresentou diferenças bilaterais significativas. Quando comparadas as relações sagitais entre si, não foram encontradas diferenças significativas, exceto para o posicionamento vertical do gônio entre as Classe II e III na assimetria severa. Conclusão: ao comparar a mesma intensidade de assimetria entre as diferentes relações esqueléticas sagitais, pouca diferença pôde ser observada. A única diferença encontrada foi em pacientes com assimetria severa, na qual os indivíduos com Classe II apresentaram maior diferença bilateral no posicionamento vertical do gônio, quando comparados àqueles com Classe III.

Comparison of the accuracy of virtual and direct bonding of orthodontic accessories

ABSTRACT Introduction: Conventional direct and indirect bonding techniques fail to obtain the ideal bracket position. Objective: To compare the accuracy of virtual and conventional direct bonding of orthodontic accessories. Methods: A single virtual configuration (dental mannequin with Class I malocclusion) served as basis for generating the reference model (treated virtually) and the intervention models (10 digital models and 10 solid models, obtained by means of prototyping). A total of 560 teeth were then equally distributed between a group of orthodontists (Group I, direct bonding; and Group II, virtual bonding), working in two different time intervals. The individual positions of the accessories were measured after three-dimensional superimposition with customized software. The Student's-t test for paired samples, and Chi-square tests were used for statistical analysis, both at the level of significance of 5%. Results: In comparison of the errors in raw values, there were significant differences only in the vertical (p< 0.001) and horizontal dimensions (p< 0.001). Considering the groups of ranges by clinical limits of the deviations, these differences were significant in the three dimensions, vertical (p< 0.001), horizontal (p= 0.044) and angular (p= 0.044). Conclusion: Virtual bonding made it possible to obtain more precise/accurate positioning of the orthodontic accessories. The potential accuracy of this method brings new perspectives to refining the indirect bonding protocols.

RESUMO Introdução: técnicas convencionais, diretas ou indiretas, de colagem de acessórios ortodônticos falham em obter a posição ideal desses. Objetivo: comparar a acurácia da colagem virtual e da colagem direta de acessórios ortodônticos por vestibular. Métodos: uma configuração virtual única (modelo de manequim com Classe I dentária) serviu como base para a geração do modelo de referência (tratado virtualmente) e dos modelos de intervenção (10 modelos digitais e 10 modelos sólidos, obtidos por prototipagem). Quinhentos e sessenta dentes foram, então, igualmente distribuídos, em dois tempos distintos, entre um grupo de ortodontistas (Grupo I: colagem direta; Grupo II: colagem virtual). As posições individuais dos acessórios foram aferidas após a sobreposição tridimensional de modelos, em software customizado. O testet de Student para amostras pareadas e o teste Qui-quadrado foram usados para a análise estatística, ambos com nível de significância de 5%. Resultados: na comparação dos erros, em valores brutos, houve diferenças significativas apenas nas dimensões vertical (p< 0,001) e horizontal (p < 0,001). Considerando-se o agrupamento de faixas por limites clínicos dos desvios, essas diferenças foram significativas nas três dimensões: vertical (p < 0,001), horizontal (p = 0,044) e angular (p = 0,044). Conclusão: a colagem virtual possibilitou um posicionamento mais preciso dos acessórios ortodônticos. Seu potencial de precisão traz novas perspectivas ao refinamento dos protocolos indiretos.

Prevalence and Associated Factors of Mandibular Asymmetry in an Adult Population.

BACKGROUND: This study aimed to estimate the prevalence of mandibular asymmetry and investigate some associated factors. METHODS: Tomographic images of 952 individuals aged from 18 to 75 years old were analyzed. The investigated outcome was mandibular asymmetry. The explanatory variables included gender, age, absence of posterior teeth, and sagittal jaw relationship of the individuals. Statistical analyses included the chi-squared and the Poisson regression with robust variance. RESULTS: Mandibular asymmetry was present in 17.4% of the sample (95% confidence interval 15.2-20.0). In the bivariate analysis, there was an association between the variables age and sagittal jaw relationship with mandibular asymmetry (P = 0.026 and P = 0.018, respectively). However, in the adjusted regression model, the association with age was not maintained, occurring only an association between sagittal jaw relationship and mandibular asymmetry (P = 0.045), with significant difference between individuals with skeletal Class II and skeletal Class III (P = 0.013). CONCLUSION: Mandibular asymmetry was not independently associated with sex, age, or absence of posterior teeth. The only verified independent association was between mandibular asymmetry and sagittal jaw relationship.

Is there an association between skeletal asymmetry and tooth absence?

INTRODUCTION: Facial skeletal asymmetry is commonly found in humans and its main characteristic is menton deviation. The literature suggests that occlusal and masticatory problems arising from tooth absence could be related to the development of such asymmetries. OBJECTIVE: The aim of this cross-sectional study was to estimate the prevalence of mandibular skeletal asymmetries and to investigate its association with posterior tooth absences. METHODS: Tomographic images of 952 individuals aged from 18 to 75 years old were used. Asymmetry was the analyzed outcome, and it was categorized into three groups according to gnathion displacement in relation to the midsagittal plane (relative symmetry, moderate asymmetry, and severe asymmetry). Patients were sorted by the presence of all posterior teeth, unilateral posterior tooth absence, or bilateral posterior tooth absence. Chi-square test with a significance level of 5% was used to verify the association between posterior tooth absence and asymmetry. RESULTS: Results show relative symmetry present in 55.3% of the sample, as well as the prevalence of 27.3% for moderate mandibular asymmetry and 17.4% for severe asymmetry. Moderate and severe mandibular asymmetries occurred in a higher proportion in patients with unilateral posterior tooth absence. However, there was no statistically significant difference between the analyzed groups (p = 0.691). CONCLUSIONS: In this study, mandibular asymmetries did not present any association with the absence of teeth on the posterior area of the arch.

Is there an association between skeletal asymmetry and tooth absence?

ABSTRACT Introduction: Facial skeletal asymmetry is commonly found in humans and its main characteristic is menton deviation. The literature suggests that occlusal and masticatory problems arising from tooth absence could be related to the development of such asymmetries. Objective: The aim of this cross-sectional study was to estimate the prevalence of mandibular skeletal asymmetries and to investigate its association with posterior tooth absences. Methods: Tomographic images of 952 individuals aged from 18 to 75 years old were used. Asymmetry was the analyzed outcome, and it was categorized into three groups according to gnathion displacement in relation to the midsagittal plane (relative symmetry, moderate asymmetry, and severe asymmetry). Patients were sorted by the presence of all posterior teeth, unilateral posterior tooth absence, or bilateral posterior tooth absence. Chi-square test with a significance level of 5% was used to verify the association between posterior tooth absence and asymmetry. Results: Results show relative symmetry present in 55.3% of the sample, as well as the prevalence of 27.3% for moderate mandibular asymmetry and 17.4% for severe asymmetry. Moderate and severe mandibular asymmetries occurred in a higher proportion in patients with unilateral posterior tooth absence. However, there was no statistically significant difference between the analyzed groups (p = 0.691). Conclusions: In this study, mandibular asymmetries did not present any association with the absence of teeth on the posterior area of the arch.

RESUMO Introdução: a assimetria esquelética facial é comum em humanos, sendo o desvio do mento sua principal característica. É sugerido, na literatura, que problemas oclusais e mastigatórios advindos das ausências dentárias teriam relação com o desenvolvimento dessas assimetrias. Objetivo: o objetivo deste estudo transversal foi estimar a prevalência de assimetrias esqueléticas mandibulares e investigar sua associação com as ausências dentárias posteriores. Métodos: foram utilizadas imagens tomográficas de 952 indivíduos, com idade entre 18 e 75 anos. A assimetria foi o desfecho analisado, sendo categorizada em três grupos, de acordo com o desvio do gnátio em relação ao plano sagital mediano: simetria relativa, assimetria moderada e assimetria severa. Os indivíduos foram agrupados segundo a presença de todos os dentes posteriores, ausência dentária posterior unilateral ou ausência dentária posterior bilateral. Para verificar a associação entre a ausência dentária posterior e a assimetria, foi utilizado o teste Χ2, ao nível de significância de 5%. Resultados: os resultados mostraram que a simetria relativa esteve presente em 55,3% da amostra, bem como uma prevalência de 27,3% para a assimetria mandibular moderada e 17,4% para assimetria severa. As assimetrias mandibulares moderada e severa ocorreram em maior proporção nos indivíduos com ausência dentária posterior unilateral; entretanto, não houve diferença estatisticamente significativa entre os grupos (p = 0,691). Conclusões: nesse estudo, as assimetrias mandibulares em adultos não apresentaram associação com a ausência de dentes na região posterior da arcada dentária.

Stability of extraction space closure.

INTRODUCTION: The objectives of this study were to evaluate the prevalence and long-term behavior of extraction space reopening in patients with Class I malocclusion and to identify some associated factors. METHODS: A sample of 43 patients met the inclusion criteria. Dental casts at the onset of treatment, after treatment, and 1 and 5 years after debonding were used. Initial and final cephalometric radiographs were used to measure the amount of incisor retraction. Cochran tests were used to compare the numbers of open and closed extraction spaces after treatment and at 1 and 5 years after debonding (P <0.05). Initial incisor crowding, amounts of anterior retraction, and angulations between the canines and the second premolars were compared between patients with and without space reopening with t tests. RESULTS: Of the sample, 30.23% had extraction space reopening. The frequency of open spaces significantly increased between the final and the 1-year posttreatment dental casts and decreased between the casts at 1 and 5 years posttreatment. Patients with space reopening had less initial anterior crowding and greater amounts of mandibular incisor retraction during treatment. CONCLUSIONS: There was a high prevalence of space reopening 1 year after treatment. However, these spaces tended to decrease by 5 years after treatment.

Facial asymmetry: a current review.

The term "asymmetry" is used to make reference to dissimilarity between homologous elements, altering the balance between structures. Facial asymmetry is common in the overall population and is often presented subclinically. Nevertheless, on occasion, significant facial asymmetry results not only in functional, but also esthetic issues. Under these conditions, its etiology should be carefully investigated in order to achieve an adequate treatment plan. Facial asymmetry assessment comprises patient's first interview, extra- as well as intraoral clinical examination, and supplementary imaging examination. Subsequent asymmetry treatment depends on patient's age, the etiology of the condition and on the degree of disharmony, and might include from asymmetrical orthodontic mechanics to orthognathic surgery. Thus, the present study aims at addressing important aspects to be considered by the orthodontist reaching an accurate diagnosis and treatment plan of facial asymmetry, in addition to reporting treatment of some patients carriers of such challenging disharmony.

Facial asymmetry: a current review

Abstract The term "asymmetry" is used to make reference to dissimilarity between homologous elements, altering the balance between structures. Facial asymmetry is common in the overall population and is often presented subclinically. Nevertheless, on occasion, significant facial asymmetry results not only in functional, but also esthetic issues. Under these conditions, its etiology should be carefully investigated in order to achieve an adequate treatment plan. Facial asymmetry assessment comprises patient's first interview, extra- as well as intraoral clinical examination, and supplementary imaging examination. Subsequent asymmetry treatment depends on patient's age, the etiology of the condition and on the degree of disharmony, and might include from asymmetrical orthodontic mechanics to orthognathic surgery. Thus, the present study aims at addressing important aspects to be considered by the orthodontist reaching an accurate diagnosis and treatment plan of facial asymmetry, in addition to reporting treatment of some patients carriers of such challenging disharmony.

Resumo O termo assimetria é utilizado quando existe uma desigualdade entre as partes homólogas, afetando, assim, o equilíbrio entre as estruturas. A assimetria facial é comum na população, e muitas vezes se apresenta de forma subclínica. Entretanto, em alguns casos existe uma assimetria facial significativa que resulta tanto em problemas funcionais quanto estéticos. Nessas circunstâncias, a etiologia deve ser cuidadosamente investigada, para que seja possível elaborar um plano de tratamento adequado. A avaliação da assimetria facial é constituída por uma anamnese do paciente, exame clínico extra e intrabucal, além de exames complementares de imagem. O tratamento subsequente dessa assimetria depende da idade do paciente, etiologia e da magnitude da desarmonia, podendo envolver desde mecânicas ortodônticas assimétricas até a realização de cirurgia ortognática. Assim, o presente artigo busca abordar aspectos importantes para que o ortodontista possa realizar um adequado diagnóstico e plano de tratamento da assimetria facial, além de relatar o tratamento de alguns pacientes portadores dessa desafiadora desarmonia.

Reliability of measurements on virtual models obtained from scanning of impressions and conventional plaster models

Aim: To evaluate the reliability of linear measurements in virtual models by comparing measurements performed on virtual models obtained from alginate impression scans, plaster model and measurements performed on conventional plaster model. Methods: The sample comprised 26 randomly selected patients to have impressions of their upper and lower jaws taken using alginate and their bite registration using a wax bite. The virtual models were obtained by scanning the alginate impression and the plaster model in a laser surface scanner (R700; 3Shape, Copenhagen, Denmark), and the measurements were performed using the Ortho Analyser (3Shape) proprietary software. The linear measurements of the size of the teeth mesial to distal, arch perimeter, intercanine distance and intermolar distance in the upper and lower arches were performed on plaster models, digital impressions and digital models, by three observers and repeated after 15 days on 8 models for intra-observer evaluations. Data were tabulated and analyzed statistically. Intra-class correlation to check the agreement of intra and inter-observers and ANOVA test were used to analyze the differences between measurements of digital models from impression and digital models from plaster. Results: The results showed a statistically significant difference (pd"0.05) for the posterior teeth, anterior teeth, upper arch perimeter and lower inter-canine distance, comparing the digital models with plaster models, but these differences are considered clinically non-significant. Conclusions: Digital models were proven be reliable and clinically acceptable for measuring tooth width, perimeter arches, intercanine and intermolar distances.

Protocolo Compass´TA: novo método para avaliação tridimensional do torque e angulação dentária utilizando modelos digitais / Compass-TA protocol: a new method for the three-dimensional torque and angulation assessment using digital impressions

Introdução: as seis chaves de oclusão normal, descritas por Lawrence Andrews em meados da década de 60, descrevem os parâmetros de inclinação e angulação normais individuais de cada dente. Objetivo: diante dos avanços tecnológicos, esse artigo tem como objetivo descrever um novo método de mensuração tridimensional da inclinação e angulação de dentes, usando modelos digitais. Métodos: após escaneamento dos modelos....., os arquivos foram importados para o software VistaDent 3D (Dentsply - Nova York, EUA), onde uma análise denominada C-TA foi criada utilizando um módulo de cefalometria tridimensional para avaliar a inclinação e angulação de cada um dos elementos dentários... Para análise da reprodutibilidade de método, foram realizadas duas mensurações de 100 elementos dentários, por um mesmo examinador calibrado. Resultados: o novo método introduzido mostrou-se excelente replicabilidade, sem diferenças estatisticamente significativas entre as duas medições realizadas, com erro casual relativamente pequeno e alto índice de correlação, estatisticamente significativa. Conclusões: a metodologia inovadora mostrou-se apta a reproduzir, de maneira fiel, o mais importante estudo da Ortodontia referente à inclinação e angulação dentária. A excelente replicabilidade e simplicidade do método permite que seja empregado em pesquisas com modelos tridimensionais, descortinando os limites da movimentação e compensação dentária, bem como explicitando os valores da oclusão normal não tratada, em diferentes grupos étnicos e padrões faciais.

Novo método para posicionamento de mini-implantes por meio de planejamento computadorizado utilizando guias cirúrgicos prototipados (TAD. GUIDE / A new method for placing mini implants using computadorized tomography combined with digital models for implant planing and prototyped surgical guides

Resumo / Apesar da facilidade na técnica cirúrgica para instalação mini-implantes ortodônticos, o correto posicionamento desses dispositivos é fundamental para a estabilidade e sucesso do tratamento. Erros de posicionamento podem causar a perda prematura, reabsorções radiculares ou inviabilizar a criação dos vetores de força desejados. Guias prototipados podem transferir para a clínica o planejamento virtual realizado a partir de tomografias computadorizadas. Apresentamos um novo método que combina os modelos digitais com as tomografias computadorizadas para geração dos guias prototipados, com maior precisão e comodidade para o clínico. O uso desse tipo de guia pode aumentar ainda mais a previsibilidade e a taxa de sucesso dos mini-implantes ortodônticos.

Prevalence of mandibular asymmetry in skeletal class I adult patients

AIM: The objective of this study was evaluating the prevalence of mandibular asymmetry in skeletal Class I adult patients. Materials and methods: The sample was composed by coneEbeam computed tomography images of 250 skeletal Class I patients with age from 18 to 70 years old. The side deviation of mandibular asymmetry was evaluated (right and left), as well as the intensity of this asymmetry. People with gnathic deviation until 2mm were considered as patients with slight asymmetry; deviation between 2 and 5mm was considered moderate asymmetry and those higher than 5mm as severe asymmetries. The error calculation method was performed and there was not significant error in the measurements. To verify the association between the prevalence of mandibular asymmetry and the gender of individuals, the Χ2 was carried out and the significant level adopted was 5% (p<0.05). RESULTS: The results showed that mandibular deviation occurred more frequently to the left side in both genders (male 56.5% e female 58.2%), without statistically significant difference between them (p=0.792). Besides, the prevalence of slight, moderate and severe asymmetries were, respectively 61%, 27% and 12% for males and 54%, 28% and 18% for female; and there was not statistically significant difference (p=0.366) between the gender of the sample evaluated. Conclusion: In this study, both deviation and intensity of mandibular asymmetry did not present preference regarding to the gender.