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.

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.

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.

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.