Pharyngeal airway subdivisions in 3-dimensional analysis: Differences between anterior and posterior anatomic boundaries.

INTRODUCTION: This study aimed to evaluate if there were differences between anterior and posterior anatomic boundaries used for the 3-dimensional determination of pharyngeal airway. METHODS: The sample included 150 cone-beam computed tomography scans from healthy patients divided according to (1) age: 6-11, 12-16, and ≥16 years; (2) sex: female and male; (3) anteroposterior skeletal pattern: Class I, II, and III; (4) vertical pattern: brachyfacial, mesofacial, and dolichofacial; and (5) craniocervical inclination (CCI): natural head posture, head flexion, and head extension. Anatomic regions were created to determine the correspondences between structures anteriorly and posteriorly to the pharyngeal airway. RESULTS: The location of the epiglottis, vallecula, hyoid, C2, and C3 were statistically different according to the CCI, and the location of vallecula, C3, and C4 were different according to sex. However, no statistically significant differences were observed between the frequencies of anterior and posterior anatomic region locations among age and different anteroposterior and vertical skeletal patterns. Posterior landmarks tend to be located below the anterior ones; consequently, the anatomic subregion they define will also be located below. CONCLUSIONS: Anterior and posterior structures and vertical and anteroposterior skeletal patterns may determine upper airway limits regardless of age. However, the studies must be paired according to sex, and CCI must be standardized.

Versatilidade de ligaduras elastoméricas na correção de rotações unitárias / The versatility of elastomeric ligatures in the correction of single tooth rotations

Resumo Introdução: As ligaduras elastoméricas, também conhecidas popularmente como "elastics", são amplamente utilizadas na ortodontia fixa há bastante tempo. Contudo, além da função de apreender o arco aos slots dos bráquetes, elas também podem ser utilizadas para correção de pequenas giroversões dentárias. Diversas marcas comerciais já desenvolveram um modelo específico de acessório elastomérico para desempenhar essa função, nomeado como "rotator"; porém, por ter um tamanho padronizado, acabam provocando sobrecorreção do movimento em determinadas situações da prática clínica. Descrição da técnica: Desta maneira, o objetivo deste artigo é ilustrar a utilização e versatilidade dos famosos "elastics", posicionados de três formas diferentes nas aletas dos bráquetes, para realizar a correção de pequenas giroversões unitárias na ortodontia fixa. Conclusão: A versatilidade de seu uso permite diferentes magnitudes de correção com praticidade (AU)

Abstract Introduction: Elastomeric ligatures, popularly known as "elastics" have been widely used in orthodontic treatment with fixed appliances for a long time. However, in addition to the function of fixating the archwires to the bracket slots, they may also be used for the correction of minor tooth rotations. Various commercial brands have developed a specific model of elastomeric accessory to perform this function, known as "rotation wedge". However, as they are of a standardized size, they end up causing overcorrection of the movement in certain clinical situations. Technique description: This article aimed to illustrate the use and versatility of the famous "elastics", positioned in 3 different ways on the bracket tie wings to effectuate correction of small single tooth rotations in orthodontic treatment with fixed appliances. Conclusion: The versatility of their use allows different magnitudes of correction with practicality. (AU)

Validity and reliability of a trigonometry-based method for the measurement of tooth movement on digital models.

OBJECTIVE: The objectives of the present study were to develop a method for longitudinally measuring tooth rotation, inclination and angulation on digital models, and to test the method validity and reliability. METHODS: The initial and final planned models of 14 patients treated with Invisalign® (386 teeth) were exported from ClinCheck®. The rotation, inclination and angulation values were assessed for the incisors, canines, premolars and molars, in both models, using trigonometry. An application was developed in Python 2.7 to automate the measurements. The ∆planned (variation in the position between the initial and final planned models) was obtained for each tooth and each type of movement. To test the validity, the degree of agreement between the ∆planned and the values available in the Invisalign® Table of Movements was assessed using the Intraclass Correlation Coefficient (ICC) and Bland-Altman analysis. For intra and inter-rater reliabilities, the ∆planned was obtained again. RESULTS: Excellent ICCs (> 0.9) and limits of agreement with narrow and clinically acceptable discrepancies were obtained for the rotation of all teeth (except maxillary canines, which had broader limits: -3.47 - 5.43) and for the inclination of premolars and molars. The inclination of anterior teeth and angulation of all teeth had ICCs and limits that were not indicative of great agreement. The reliability was high for the three movements (discrepancy <2°). CONCLUSIONS: The method developed is reliable and suitable for longitudinally measuring inclination (posterior teeth) and rotation (except maxillary canines). It has limited value for the other movements measurements.

Validity and reliability of a trigonometry-based method for the measurement of tooth movement on digital models

ABSTRACT Objective: The objectives of the present study were to develop a method for longitudinally measuring tooth rotation, inclination and angulation on digital models, and to test the method validity and reliability. Methods: The initial and final planned models of 14 patients treated with Invisalign® (386 teeth) were exported from ClinCheck®. The rotation, inclination and angulation values were assessed for the incisors, canines, premolars and molars, in both models, using trigonometry. An application was developed in Python 2.7 to automate the measurements. The ∆planned (variation in the position between the initial and final planned models) was obtained for each tooth and each type of movement. To test the validity, the degree of agreement between the ∆planned and the values available in the Invisalign® Table of Movements was assessed using the Intraclass Correlation Coefficient (ICC) and Bland-Altman analysis. For intra and inter-rater reliabilities, the ∆planned was obtained again. Results: Excellent ICCs (> 0.9) and limits of agreement with narrow and clinically acceptable discrepancies were obtained for the rotation of all teeth (except maxillary canines, which had broader limits: -3.47 - 5.43) and for the inclination of premolars and molars. The inclination of anterior teeth and angulation of all teeth had ICCs and limits that were not indicative of great agreement. The reliability was high for the three movements (discrepancy <2°). Conclusions: The method developed is reliable and suitable for longitudinally measuring inclination (posterior teeth) and rotation (except maxillary canines). It has limited value for the other movements measurements.

RESUMO Objetivo: Os objetivos do presente estudo foram desenvolver um método para medir longitudinalmente a rotação, inclinação e angulação dentárias em modelos digitais, e testar sua validade e reprodutibilidade. Material e Métodos: Os modelos inicial e final planejado de 14 pacientes tratados com Invisalign® (386 dentes) foram exportados do ClinCheck®. Os valores de rotação, inclinação e angulação foram calculados para incisivos, caninos, pré-molares e molares, em ambos os modelos, por meio de trigonometria. Um aplicativo desenvolvido em Python 2.7 foi utilizado para automatização das medidas. O ∆planejado (variação na posição entre os modelos inicial e final planejado) foi obtido para os movimentos descritos, nos diferentes grupos de dentes. A validade do método foi verificada pelo grau de concordância entre o ∆planejado e os valores disponíveis na Tabela de Movimentos do Invisalign®, utilizando-se o Coeficiente de Correlação Intraclasse (ICC) e a análise de Bland-Altman. O ∆planejado foi novamente calculado para análise da reprodutibilidade intra e interexaminadores. Resultados: Excelentes ICCs (> 0,9) e limites de concordância com discrepâncias reduzidas e clinicamente aceitáveis foram obtidos para a rotação de todos os dentes (exceto os caninos superiores, que expressaram limites mais amplos: -3,47 - 5,43) e para a inclinação de pré-molares e molares. A inclinação dos dentes anteriores e a angulação de todos os dentes apresentaram ICCs e limites não representativos de boa concordância. A reprodutibilidade foi alta para os três movimentos (discrepância < 2°). Conclusões: O método desenvolvido é reprodutível e se mostrou adequado para mensuração longitudinal da inclinação de dentes posteriores e rotação de todos os dentes, exceto caninos superiores. Apresenta valor limitado para as demais mensurações.

Effect of rapid maxillary expansion on nasal cavity assessed with cone-beam computed tomography.

INTRODUCTION: Rapid maxillary expansion (RME) is assumed as a well established procedure; although, some effects on facial complex are not yet fully understood. OBJECTIVE: The aim of this research was to verify, using cone-beam computed tomography, the effect on linear dimensions of the nasal cavity. METHODS: Sample consisted of twenty patients aged 7 to 16 years, with skeletal deformity that justified the use of CT scans, and who required the RME as part of the orthodontic treatment planning. Scans were taken before clinical procedures were performed (T0) and after stabilizing the expander screw (T1). Dolphin Imaging v. 11.5 3D software was used to measure six areas on nasal cavity: three at the anterior portion (upper, middle, and lower) and other three at the posterior portion (also upper, middle, and lower). Data were statistically treated using Shapiro-Wilk test to verify normality. Differences between T0 and T1 were calculated using the Spearman correlation and paired Student's t-test, with a significance level of 5%. RESULTS: All linear measurements presented a significant increase (p< 0.05) after RME, both in the anterior and posterior regions, suggesting some parallelism on the opening pattern, especially at the lower portion (p< 0.001). CONCLUSIONS: RME was able to significantly modify the internal dimensions of the nasal cavity.

Effect of rapid maxillary expansion on nasal cavity assessed with cone-beam computed tomography

ABSTRACT Introduction: Rapid maxillary expansion (RME) is assumed as a well established procedure; although, some effects on facial complex are not yet fully understood. Objective: The aim of this research was to verify, using cone-beam computed tomography, the effect on linear dimensions of the nasal cavity. Methods: Sample consisted of twenty patients aged 7 to 16 years, with skeletal deformity that justified the use of CT scans, and who required the RME as part of the orthodontic treatment planning. Scans were taken before clinical procedures were performed (T0) and after stabilizing the expander screw (T1). Dolphin Imaging v. 11.5 3D software was used to measure six areas on nasal cavity: three at the anterior portion (upper, middle, and lower) and other three at the posterior portion (also upper, middle, and lower). Data were statistically treated using Shapiro-Wilk test to verify normality. Differences between T0 and T1 were calculated using the Spearman correlation and paired Student's t-test, with a significance level of 5%. Results: All linear measurements presented a significant increase (p< 0.05) after RME, both in the anterior and posterior regions, suggesting some parallelism on the opening pattern, especially at the lower portion (p< 0.001). Conclusions: RME was able to significantly modify the internal dimensions of the nasal cavity.

RESUMO Introdução: A expansão rápida da maxila (ERM) é um procedimento bem estabelecido. Entretanto, alguns efeitos no complexo facial ainda não foram completamente compreendidos. Objetivo: O objetivo do presente estudo foi verificar o efeito da ERM nas medidas lineares da cavidade nasal, utilizando a tomografia computadorizada de feixe cônico (TCFC). Métodos: A amostra foi composta por 20 pacientes da Universidade Federal da Bahia, com idades entre 7 e 16 anos, com deformidades esqueléticas que justificavam o uso da TCFC e que necessitavam da ERM como parte do tratamento ortodôntico. As imagens tomográficas foram realizadas antes dos procedimentos clínicos (T0) e após estabilização do parafuso expansor (T1). O software Dolphin Imaging v. 11.5 3D (Dolphin, Chatsworth, CA, EUA) foi utilizado para mensurar seis áreas na cavidade nasal, três delas na região anterior (superior, média e inferior) e outras três na região posterior (também superior, média e inferior). Os dados foram trabalhados estatisticamente, utilizando o teste de Shapiro-Wilk para avaliar a normalidade. Diferenças entre T0 e T1 foram calculadas usando a Correlação de Spearman e o teste t de Student pareado, usando um nível de significância de 5%. Resultados: Todas as mensurações lineares apresentaram um aumento significativo (p< 0,05) após a ERM, tanto na região anterior quanto na posterior, sugerindo algum paralelismo no padrão de abertura, principalmente na porção inferior (p< 0,001). Conclusão: A ERM foi capaz de modificar significativamente as dimensões internas da cavidade nasal.

Is the buccal alveolar bone less affected by mini-implant assisted rapid palatal expansion than by conventional rapid palatal expansion?-A systematic review and meta-analysis.

OBJECTIVE: To systematically review the existing literature comparing mini-implant assisted rapid palatal expansion (MARPE) and conventional rapid palatal expansion (RPE) regarding the effect on the buccal alveolar bone thickness (BT) and marginal bone level (BL). METHODS: PubMed/MEDLINE, Scopus, Web of Science, The Cochrane Library, Virtual Health Library, Embase, Ovid, LIVIVO, CINAHL, the Portal de Periódicos da CAPES, Google Scholar and SIGLE were searched up to January 2020. Risk of bias (RoB) assessments were performed using the Cochrane Collaboration and ROBINS-I tools. Fixed-effects meta-analysis of standardized mean differences (SMD) was implemented to assess the pooled estimates for the BT outcome. The analyses were performed adopting a significance level of 5%. A narrative synthesis was performed to summarize the results on the BL. The GRADE tool was used to assess the quality of the evidence. RESULTS: Three randomized clinical trials and one retrospective study were included. Only one study was rated as with low RoB, while the others were scored as with moderate to serious RoB. Limited evidence indicated that patients using conventional RPE had a greater loss of the BT compared to patients using MARPE (SMD = 0.55; 95% CI: 0.29-0.80; P < .0001). Subgroup analyses showed that differences were significant in both premolars' regions, right (SMD = 0.75; 95% CI: 0.24-1.25; P = .004) and left (SMD = 1.05; 95% CI: 0.52-1.57; P < .0001), and these were not significant for the molars' regions (P > .05) (Low quality of evidence). LIMITATIONS: Limited amount of selected papers, methodological issues that could lead to bias and high clinical heterogeneity among the studies. Due to the statistical model applied for the quantitative synthesis of the results, no generalization to any other population is recommended. CONCLUSIONS: Limited evidence suggests that MARPE could decrease the loss of the buccal alveolar bone when compared to conventional RPE.

Mecânica simples e eficaz para desimpactar molares inferiores na dentição mista / Management of lower molar impaction during mixed dentition ­ a simple and effective mechanic

Resumo A erupção ectópica de molares inferiores é na prática clínica muito frequente, fazendo-se necessário redirecionar o trajeto de erupção, para evitar a reabsorção da raiz do dente adjacente, lesões cariosas, problemas periodontais, bem como outras intercorrências. Contudo, realizar a correção desses dentes utilizando apenas a Ortodontia interceptativa nem sempre é tarefa das mais fáceis. Sendo assim, o objetivo deste trabalho foi apresentar uma alternativa simples, confortável e de baixo custo para desimpacção de molares inferiores durante a dentição mista. Foi proposto para isso um arco lingual associado à incorporação de acessório, permitindo que uma mola helicoidal possa ser inserida e retirada para ativação a qualquer momento, independe da colaboração do paciente, redirecionando assim o trajeto de erupção do dente nos tratamentos ortodônticos interceptativos. (AU)

Abstract Lower molar ectopic eruption is very frequently found in clinical practice and redirecting its eruption path may be necessary to avoid adjacent tooth root resorption, tooth decay, periodontal problems, among others issues. However, its correction with interceptive orthodontics during the mixed dentition may be a challenge. Therefore, the aim of this paper is to present a simple, comfortable and effective manner of managing lower molar impaction during the mixed dentition. A lingual arch associated to an accessory attached to the occlusal surface of the impacted tooth and a helicoidal spring was proposed. The spring was designed in a manner it can be inserted and removed at any time for activation, not depending on patient cooperation and allowing redirection of the tooth eruption path during interceptive treatment.(AU)

Tooth extractions in Orthodontics: first or second premolars?

Tooth crowding and protrusions demand rigorous attention during orthodontic planning that includes the extraction of first and second premolars. Some characteristics, such as dentoalveolar bone discrepancies, maxillomandibular relations, facial profile, skeletal maturation, dental asymmetries and patient cooperation, are important elements of an orthodontic diagnosis. This study discusses the options of treatments with extractions and describes the correction of a Class I malocclusion, bimaxillary protrusion, severe anterior crowding in both dental arches and tooth-size discrepancy, using first premolar extractions.

Tooth extractions in Orthodontics: first or second premolars?

ABSTRACT Tooth crowding and protrusions demand rigorous attention during orthodontic planning that includes the extraction of first and second premolars. Some characteristics, such as dentoalveolar bone discrepancies, maxillomandibular relations, facial profile, skeletal maturation, dental asymmetries and patient cooperation, are important elements of an orthodontic diagnosis. This study discusses the options of treatments with extractions and describes the correction of a Class I malocclusion, bimaxillary protrusion, severe anterior crowding in both dental arches and tooth-size discrepancy, using first premolar extractions.

RESUMO Apinhamentos e protrusões dentárias têm requerido rigor durante o planejamento ortodôntico envolvendo exodontias de primeiros e segundos pré-molares. Algumas características como discrepância entre dentes e suas respectivas bases ósseas, relacionamento maxilomandibular, perfil facial, maturação esquelética, assimetrias dentárias, patologias e cooperação do paciente têm sido consideradas elementos importantes de diagnóstico ortodôntico. Sendo assim, o presente artigo teve por objetivo discutir as opções de tratamento com extrações dentárias e apresentar a correção de uma má oclusão de Classe I, biprotrusão, com severo apinhamento anterior em ambas as arcadas e discrepância de tamanho dentário, por meio da exodontia de primeiros pré-molares.

Percepção estética sobre alterações no terço inferior da face em diferentes regiões do Brasil e a decisão pelo tratamento ortodôntico cirúrgico / Aesthetic perception of changes in the lower third of the face in different regions of Brazil and the decision for surgical orthodontic treatment

Os autores avaliaram em todo o Brasil, o impacto que o posicionamento anteroposterior da mandíbula e alterações verticais na dimensão estômio-mento (St-Me) geram sobre leigos, cirurgiões bucomaxilofaciais e ortodontistas, suas indicações ao tratamento ortodôntico-cirúrgico, bem como, a prevalência do gênero, idade, grupo racial, estruturas ósseas e os tipos de intervenções cirúrgicas realizadas com maior frequência nos seus pacientes com desarmonias dentofaciais. Material e métodos: quatro modelos (duas mulheres e dois homens, leucodermas e melanodermas) foram fotografados em norma frontal e perfil. A dimensão St-Me (vertical) foi aumentada e diminuída em 10 e 20% e o ângulo da convexidade facial (anteroposterior) aumentado e diminuído em 4 e 8º. As imagens foram avaliadas em escala visual analógica por meio de questionários. Resultados: as imagens originais foram significativamente mais atrativas e as grandes alterações menos estéticas. Os cirurgiões bucomaxilofaciais e ortodontistas foram mais exigentes que os leigos e aqueles com menor grau de escolaridade, não conseguiram perceber alterações faciais verticais mais sutis. Os melanodermas foram mais estéticos quando apresentaram suave aumento de 10%, no sentido vertical. O oposto foi observado nos indivíduos leucodermas. Em relação ao gênero, as grandes alterações foram sempre menos atrativas, comparadas às pequenas alterações. Quanto às indicações cirúrgicas, os leigos foram mais tolerantes e os cirurgiões tanto indicariam quanto se submeteriam mais às cirurgias, caso as imagens fossem das próprias faces. Os leucodermas receberam as mesmas indicações às cirurgias, quando o terço inferior da face esteve aumentado (20%) e projetado (8º), e os melanodermas diferiram quanto à discrepância sagital. As mulheres receberam mais indicação à cirurgia nas simulações sagitais para Classe III, e os homens para Classe II. Epidemiologicamente, o gênero feminino foi o mais prevalente (75%) em todas as regiões do Brasil, na faixa etária entre 20 e 30 anos (71%) e leucodermas (75%). A estrutura óssea com mais indicações foi "ambas" (maxila e mandíbula) com 53,76%. Nas regiões Norte, Nordeste e Sul a segunda mais prevalente foi a mandíbula, enquanto no Centro-Oeste e Sudeste foi a maxila. Das intervenções cirúrgicas de um modo geral, o avanço maxilar foi o mais prevalente, seguido do recuo mandibular (23,67% e 23,33%, respectivamente) em todas as regiões. Conclusão: A dimensão St-Me e o ângulo da convexidade facial exerceram forte influência sobre a estética facial e a percepção para a necessidade de cirurgia ortognática, em todas as regiões do Brasil. A maioria dos pacientes atendidos pelos profissionais foi mulheres, jovens, leucodermas que apresentavam alterações esqueléticas em ambos os maxilares, com indicações e submissões às cirurgias combinadas, sobretudo para avanço maxilar e recuo mandibular. (AU)

This study evaluated throughout Brazil the impact of the anteroposterior positioning of the mandible and vertical changes in the Stomium-Mentum dimension (St-Me) on laypersons, bucomaxilofacial surgeons and orthodontists, their indications for orthodontic-surgical treatment, and prevalence of gender, age, racial group, bone structures and types of surgical interventions performed more frequently in their patients with dentofacial disharmonies. Material and methods: Four models (two women and two men, leucoderma and melanoderma) had frontal and lateral photographs taken. The St-Me dimension (vertical) was increased and decreased by 10 and 20% and the angle of facial convexity (anteroposterior) increased and decreased by 4 and 8º. The images were assessed with a Visual Analogue Scale questionnaire. Results: the original images were significantly more attractive, and major changes were less aesthetic. Bucomaxilofacial surgeons and orthodontists were more demanding than laypersons and those with lower educational level were unable to notice subtle vertical facial changes. Melanoderma individuals, were more aesthetic when presented a slight increase of 10% in the vertical direction. The opposite was observed in leucoderma subjects. Regarding gender, the major changes were always less attractive, compared to small ones. As far as the surgical indications, the laypersons were more tolerant, and the surgeons would both indicate and undergo surgeries if the images were from their own faces. The leucoderma subjects received the same indications for the surgeries, when the lower-third facial was increased (20%) and projected (8º), and the melanoderma ones differed as to the sagittal discrepancy. Women had more indication for surgery in the sagittal simulations for Class III and men for Class II. Epidemiologically, female gender was the most prevalent (75%) in all regions of Brazil, in the age group between 20 and 30 years (71%) and leucoderma (75%). The bone structure with more indications was "both" (maxilla and mandible) with 53.76%. In the North, Northeast and South regions, the second most prevalent was the mandible, while in the Midwest and Southeast it was the maxilla. Among the general surgical interventions, maxillary advancement was the most prevalent, followed by mandibular retreatment (23.67% and 23.33%, respectively) in all regions. Conclusion: The St-Me dimension and the facial convexity angle wielded a strong influenced facial aesthetics and the perception of the need for orthognathic surgery in all Brazilian regions. Most of the patients with dentofacial disharmonies are women, young, leucoderma, with skeletal alterations in both maxillary bones, submitted or with indication of combined surgery, predominantly maxillary advancement and mandibular setback.

Proposal of surface electromyography signal acquisition protocols for masseter and temporalis muscles

Abstract Introduction The aim of this study was to propose a method of electrodes positioning on the superficial masseter and anterior temporalis muscles for surface electromyographic (sEMG) recordings in order to overcome some known methodological constraints. Methods Fifteen volunteers with normal occlusion participated in two experimental sessions within a 7 day-period. Surface electrodes were placed on two different locations that were based on palpable and individual anatomical references. Surface EMG signals (2000 Hz per channel; A/D: 16 bits; gain: 2000 X; band-pass filter: 20-500 Hz) were recorded under three conditions: mandibular rest position, 30% and 100% of maximum voluntary bite force. Three measurements of maximal bite force were taken by using a force transducer positioned over the lower right first molar region and the highest record was taken into account. The root mean square value was considered for analysis. Intraclass correlation coefficients (ICCs), paired t test, and the Bland-Altman method comprised the statistical analyses. The level of significance was set at 0.05. Results ICC records for right and left masseter and anterior temporalis muscles at T0 (first sEMG record) and T7 (second sEMG record) intervals were significantly different (p<0.05). The results showed satisfactory to excellent reproducibility of RMS values at rest, MVBF and 30% MVBF, as well as for MVBF in kgf. Conclusion The results showed reliable reproducibility for the sEMG signal recording in masseter and anterior temporalis muscles from the protocols presented and under the three conditions investigated.

Preparation and evaluation of orthodontic setup

INTRODUCTION: An orthodontic or diagnostic setup consists in cutting and realigning the teeth in plaster models, making it an important resource in orthodontic treatment planning. OBJECTIVE: The aim of this article is to provide a detailed description of a technique to build an orthodontic setup model and a method to evaluate it. CONCLUSIONS: Although laborious, orthodontic setup procedure and analysis can provide important information such as the need for dental extractions, interproximal stripping, anchorage system, among others.