Elaboración de modelos dentales didácticos en resina epóxica / Elaboration of didactic dental models in epoxy resin

Los modelos de estudio son un registro fundamental para el diagnóstico, el plan de tratamiento, la presentación de caso y la evaluación del progreso del tratamiento dental; son registros anatomofisiológicos de las arcadas dentarias que sirven para evaluar la dentición en los tres planos del espacio y la oclusión en la relación cúspide-fosa, en una dimensión estática y dinámica. Para obtener los modelos de estudio es imprescindible obtener impresiones totales con diversos materiales de impresión de los arcos dentarios, que reproduzcan fielmente todos los detalles anatómicos, para posteriormente obtener un modelo en yeso piedra. Los modelos obtenidos a partir de una impresión generalmente son a base de yeso odontológico, los cuales a pesar de sus mejoras aún conservan algunas características negativas como: baja resistencia a la fractura por impacto, baja resistencia al desgaste por abrasión, inestabilidad dimensional y radiopacidad que impide la simulación de procedimientos endodóncicos. Con la finalidad de mejorar la simulación en la práctica odontológica, se usa la resina epóxica que puede emplearse en la obtención de modelos, este material es más resistente y presenta una mayor resistencia a la abrasión; además es radiolúcido, por lo que es útil para la réplica de preparaciones y procedimientos de simulación endodóntica. Los detalles de la superficie obtenidos con resina epóxica son superiores a los obtenidos con yeso. El uso de simuladores es una herramienta educativa con la que se favorece la adquisición de ciertas habilidades, destrezas, técnicas y competencias necesarias para la formación de estudiantes o profesionales de odontología. En el presente trabajo se describe la técnica para la elaboración de modelos dentales didácticos en resina epóxica para utilizarlos en la enseñanza de la práctica odontológica (AU)

Study studies are a fundamental record for diagnosis, treatment plan, case presentation and evaluation of the progress of dental treatment. They are anatomo-physiological records of the dental arches to evaluate the dentition in the three planes of space and the occlusion in the cusp-fossa relationships, in a static and dynamic dimension. To obtain the study models, it is essential to obtain total impressions with various impression materials of the dental arches, which faithfully reproduce all the anatomical details, in order to later obtain a stone plaster model. Those obtained from an impression are generally based on dental plaster, which despite its improvements still retain some negative characteristics such as: low resistance to fracture by impact, low resistance to wear by abrasion, dimensional instability and radio opacity that prevents the simulation of endodontic procedures. In order to improve simulation in dental practice, the use of epoxy resin can be used to obtain models, this material is more resistant and has greater resistance to abrasion, it is radiolucent, which makes them Useful for replicating preparations and endodontic simulation procedures, the surface details obtained with epoxy resin are superior to those obtained with plaster. The use of simulators is an educational tool that favors the acquisition of certain abilities, skills, techniques and competencies necessary for the training of the student or professional in dentistry. In the present work, the technique for the elaboration of didactic dental models in epoxy resin to be used in the teaching of dental practice is described.(AU)

Comparison of the perception of orthodontists and general clinicians on the use of digital dental models in the city of Aracaju/Sergipe / Comparação da percepção de ortodontistas e clínicos gerais sobre o uso de modelos digitais odontológicos na cidade de Aracaju / Sergipe

ABSTRACT Context: Digital study models have become a safe and advantageous alternative for diagnosis and planning in dentistry. Despite the superior characteristics in comparison with traditional plaster models, professionals seem to resist the use of new technologies. Aims: To assess the level of knowledge and the use of digital models through a questionnaire applied to dental professionals. Methods: A questionnaire with 12 multiple-choice questions about plaster models, digital, and use of the 3Shape - 3D viewer software was answered by 76 orthodontists (42 women and 34 men; mean age =37.82 years (SD ± 7.60)) and 30 general dental surgeons (18 women and 12 men; mean age of 33.93 years (SD ± 8.45)) in Aracaju, Sergipe, Brazil. Data were tabulated in Excel spreadsheets and then analyzed using the SPSS statistical software version 20. An absolute analysis of frequency and percentage of responses was performed. Results: Most professionals reported using plaster models and claimed their low cost as justification for their use (P = 0.001). Aware of the benefits of digital models, professionals of both classes highlighted the facilitated storage and search for information as the main advantages, the cost and infrastructure as the main disadvantages. Regarding the use of the 3Shape - 3D viewer software, orthodontists showed better utilization of this resource than general dental surgeons (P = 0.0198). Conclusion: It verified that most professionals make use of plaster models. However, despite knowing the advantages of digital models, their cost is sees as a limiting factor for adherence to this technology.

RESUMO Contexto: Os modelos digitais de estudo têm se tornado uma alternativa segura e vantajosa para o diagnóstico e planejamento em odontologia. Apesar das características superiores em comparação aos modelos tradicionais de gesso, os profissionais parecem resistir ao uso de novas tecnologias. Objetivos: Avaliar o nível de conhecimento e a utilização de modelos digitais por meio de questionário aplicado a profissionais da área odontológica. Material e Métodos: Questionário com 12 questões de múltipla escolha sobre modelos de gesso, digitais e uso do software 3Shape - 3D viewer foi respondido por 76 ortodontistas (42 mulheres e 34 homens; idade média = 37,82 anos (DP = ± 7,60) ) e 30 cirurgiões-dentistas gerais (18 mulheres e 12 homens; média de idade de 33,93 anos (DP = ± 8,45)) em Aracaju, Sergipe, Brasil. Os dados foram tabulados em planilhas do Excel e posteriormente analisados no software estatístico SPSS versão 20. Foi realizada uma análise absoluta de frequência e percentual de respostas. Resultados: A maioria dos profissionais relatou utilizar modelos de gesso e alegou seu baixo custo como justificativa para seu uso (P = 0,001). Cientes dos benefícios dos modelos digitais, os profissionais de ambas as classes destacaram o armazenamento facilitado e a busca de informações como as principais vantagens, o custo e a infraestrutura como as principais desvantagens. Em relação à utilização do software 3Shape - 3D viewer, os ortodontistas apresentaram melhor aproveitamento desse recurso do que os cirurgiões-dentistas gerais (P = 0,0198). Conclusões: Verificou-se que a maioria dos profissionais faz uso de modelos de gesso. Porém, apesar de conhecer as vantagens dos modelos digitais, seu custo é visto como um fator limitante para a adesão a essa tecnologia.

Métodos para medir asimetrías sagitales y transversales en los modelos de estudio de ortodoncia / Methods to measure sagittal and transverse asymmetries in orthodontic study models

Introducción Para el diagnóstico acertado en el tratamiento de los pacientes de ortodoncia se requiere de una serie de exámenes auxiliares, que son herramientas esenciales en ortodoncia; sin embargo, encontramos cierto grado de dificultad para la valoración de asimetrías dentarias en los hemiarcos de cada arcada dentaria; la importancia de la correcta valoración de las asimetrías es ya ampliamente mencionada en diferentes estudios, porque nos ayudará con la localización co-rrecta, de los dientes en su arcada,al final del tratamiento En la actualidad existe poca literatura sobre los métodos para evaluar y diagnosticar las alteraciones por hemiarcos, especialmente en el plano transversal. Objetivo acer una revisión de literatura sobre los métodos de medición de las asimetrías dentarias intra-arco para poder identificar y cuantificar las alteraciones dentarias en los tres planos del espacio en su respectiva arcada dentaria, el Método para los términos de búsqueda de la información fueron: dental and facial asymmetry, molar asymmetry in ortho-dontics, arch width prediction indices, as well as transverse discrepancies, para tal efecto se empleó Pubmed, Medline, Scielo, Schoolar Google, de los cuales se recopilaron 80 artículos relacionados con nuestro tema de estudio y solo se eligieron 30 artículos y 6 libros de ortodoncia en los que se sustenta este artículo. Resultados En el presente artículo presentamos las herramientas con las que contamos para el diagnóstico de la asimetría dentaria intra-arcos como la placa de Sthmuch y la placa milimetrada de Korkhaus, y finalmente proponemos un método que nos permite cuantificar objetivamente la asimetría en los tres plano del espacio de una manera sencilla, reproducible y de fácil almacenaje en un computador. Conclusión La etapa del diagnóstico es importante porque permitirá obtener la mayor y mejor información de las alteraciones dentarias que presenta el paciente, siendo las alteraciones transversales las más difíciles de cuantificar por que la mayoría de los estudios e índices, ya que solo evidencian las distancias de dientes contra laterales, los cuales son datos limitados pero que aún así contribuyen en el diagnóstico, el método de la placa de Sthmuch, Korkhaus y Bernklau son propuesta para medir las asimetrías dentarias intraarcos, no en tanto es desgastador para el operador y sus resultados objetivos radica en la experiencia del operador; el método KLO nos permite cuantificar objetivamente la falta de sime-tría dentaria en cada arcada de una manera fácil, reproducible y de almacenaje en un computador o en un archivo.

Introduction The correct diagnosis in the treatment of orthodontic patients requires a series of auxiliary examinations, which are essential tools in orthodontics, however we found a certain de-gree of difficulty in assessing dental asymmetries in the hemiarchs of each dental arch; The im-portance of the correct assessment of asymmetries is already widely mentioned in different stud-ies, because it will help us with the correct location of the teeth in their arch, at the end of the treatment. Currently there is little literature on the methods to evaluate and diagnose hemiarchal alterations, especially in the transverse plane. Objective Is to review the literature on the methods of measuring intra-arch dental asymmetries in order to identify and quantify dental al-terations in the three planes of space in their respective dental arch. Method The search terms of the information were: dental and facial asymmetry, molar asymmetry in orthodontics, arch width prediction indices, as well as cross-sectional discrepancies. Pubmed, Medline, Scielo, Schoolar Google, of which 80 articles related to our study topic were collected and only 30 articles and 6 orthodontic books were chosen on which this article is based, Results Also in this article we present the tolos that we have for the diagnosis of intraarch dental asymmetry such as the Sth-much plate and the Korkhaus millimeter plate, and finally we propose a method that allows us to objectively quantify the asymmetry in the three space plan in a simple, reproducible way and easy to store on a computer. Conclusión The stage of diagnosis is important because it will allow obtain-ing the greatest and best information on the dental alterations that the patient presents, being the transversal alterations the most difficult to quantify because most studies and indices, since they only show the distances of Contralateral teeth, which are limited data but still contribute to the diagnosis, the Sthmuch, Korkhaus and Bernklau plate method are proposed to measure intra-arch dental asymmetries, not as it is wearisome for the operator and his patients. objective results lies in the experience of the operator; The KLO method allows us to objectively quantify the lack of dental symmetry in each arch in an easy, reproducible way that can be stored on a computer or in a file.

Evaluation of an open access generic 3D software for Orthodontic diagnosis and treatment planning

Aim: To evaluate the accuracy and the validity of orthodontic diagnostic measurements, as well as virtual tooth transformations using a generic open access 3D software compared to OrthoAnalyzer (3Shape) software; which was previously tested and proven for accuracy. Methods: 40 maxillary and mandibular single arch study models were duplicated and scanned using 3Shape laser scanner. The files were imported into the generic and OrthoAnalyzer software programs; where linear measurements were taken twice to investigate the accuracy of the program. To test the accuracy of the program format, they were printed, rescanned and imported into OrthAnalyzer. Finally, to investigate the accuracy of editing capabilities, linear and angular transformation procedures were performed, superimposed and printed to be rescanned and imported to OrthoAnalyzer for comparison. Results: There was no statistically significant difference between the two groups using the two software programs regarding the accuracy of the linear measurements (p>0.05). There was no statistically significant difference between the different formats among all the measurements, (p>0.05). The editing capabilities also showed no statistically significant difference (p>0.05). Conclusion: The generic 3D software (Meshmixer) was valid and accurate in cast measurements and linear and angular editing procedures. It can be used for orthodontic diagnosis and treatment planning without added costs

Congruencia entre modelos dentales impresos 3D y el archivo digital de origen: estudio in vitro comparativo de 5 impresoras 3D / Congruence between 3D printed dental models and the original digital file: comparative in vitro study of 5 3D printers

Este trabajo tuvo como objetivo conocer la fiabilidad de la impresora 3D (i3D) aditiva por Matriz de Proceso Digital de Luz (MDLP) Hellbot modelo Apolo®, a través de verificar la congruencia dimensional entre las mallas de modelos impresos (MMi) y su correspondiente archivo digital de origen (MMo), obtenido del software de planificación ortodontica Orchestrate 3D® (O3D). Para determinar su uso en odontología y sus posibilidades clínicas, fue comparada entre cinco i3D de manufactura aditiva, dos DLP, dos por estereolitografía (SLA) y una por Depósito de Material Fundido (FDM). La elección de las cinco i3D se fundamentó en su valor de mercado, intentando abarcar la mayor diversidad argentina disponible. Veinte modelos fueron impresos con cada i3D y escaneados con Escáner Intraoral (IOS) Carestream modelo 3600® (Cs3600). Las 120 MMi fueron importadas dentro del programa de ingeniería inversa Geomagic® Control X® (Cx) para su análisis 3D, consistiendo en la superposición de MMo con cada una de las MMi. Luego, una evaluación cualitativa de la desviación entre la MMi y MMo fue realizada. Un análisis estadístico cuidadoso fue realizado obteniendo como resultado comparaciones en 3d y 2d. Las coincidencias metrológicas en la superposición tridimensional permitieron un análisis exhaustivo y fácilmente reconocible a través de mapas colorimétricos. En el análisis bidimensional se plantearon planos referenciados dentariamente desde la MMo, para hacer coincidir las mediciones desde el mismo punto de partida dentaria. Los resultados fueron satisfactorios y muy alentadores. Las probabilidades de obtener rangos de variabilidad equivalentes a +/- 50µm fueron de un 40,35 % y de +/- 100µm un 71,04 %. Por lo tanto, te- niendo en cuenta las exigencias de congruencia dimensional clínicas de precisión y exactitud a las cuales es sometida nuestra profesión odontológica, se evitan problemas clínicos arrastrados por los errores dimensionales en la manufactura (Cam) (AU)

The objective of this study was to determine the reliability of the Hellbot Apollo® model additive 3D printer (i3D) by Matrix Digital Light Processing (MDLP) by verifying the dimensional congruence between the printed model meshes (MMi) and their corresponding digital source file (MMo), obtained from the Orchestrate 3D® (O3D) orthodontic planning software. A comparison was made between five i3D of additive manufacturing, two DLP, two by stereolithography (SLA), and one by Fused Material Deposition (FDM), to determine its use in dentistry and its clinical possibilities. The choice of the five i3D was based on their market value, trying to cover most of the Argentinean diversity available. Twenty models were printed with each i3D and scanned with Carestream Intraoral Scanner (IOS) model 3600® (Cs3600). The 120 MMi were imported into the reverse engineering program Geomagic® Control X® (Cx) for 3D analysis, consisting of overlaying MMo with each MMi. Then, a qualitative evaluation of the deviation between MMi and MMo. Also, a careful statistical analysis was performed, resulting in 3d and 2d comparisons. Metrological coincidences in three-dimensional overlay allowed a comprehensive and easily recognizable analysis through colorimetric maps. In the two-dimensional analysis, dentally referenced planes were proposed from the MMo, to match the measurements from the same dental starting point. The results were satisfactory and very encouraging. The probabilities of obtaining ranges of variability equivalent to +/- 50µm were 40.35 % and +/- 100µm 71.04 %. Therefore, considering the demands of clinical dimensional congruence, precision, and accuracy to which our dental profession it is subjected, clinical problems caused by dimensional errors in manufacturing (Cam) are avoided (AU)

In vitro evaluation of positioning accuracy of trephine bur at different depths by dynamic navigation / 北京大学学报(医学版)

OBJECTIVE@#To evaluate the accuracy of trephine bur drilling at different depths guided by dynamic navigation system in 3D printing in vitro model.@*METHODS@#A model at the depth of 5 mm, 10 mm, and 15 mm from the outer surface of which hemispherical cavities was reserved and the 3D printing technology was used to make the standardized model with Veroclear resin. The cone beam CT (CBCT) was taken and the data were imported into the dynamic navigation software (DCARER, China) to establish navigation path programming. Under the guidance of dynamic navigation, a trephine bur with a diameter of 4.5 mm was used to complete the access operation. At each depth, 10 approaches were completed. The postoperative model CBCT was taken. The approach trajectory under navigation was reconstructed and compared with the designed path. The two-dimensional distance deviation, depth deviation, three-dimensional distance deviation, and angle deviation between the actually prepared path and the designed path were calculated.@*RESULTS@#At the depth of 5 mm, the two-dimensional distance deviation between the end position of the prepared path and the designed path was (0.37±0.06) mm, the depth deviation was (0.06±0.05) mm, the three-dimensional distance deviation was (0.38±0.07) mm, and the angle deviation was 2.46°±0.54°; At the depth of 10 mm, the four deviations between the end position of prepared path and the designed path were (0.44±0.05) mm, (0.16±0.06) mm, (0.47±0.05) mm, and 2.45°±1.21°, respectively; At the depth of 15 mm, the four deviations were (0.52±0.14) mm, (0.16±0.07) mm, (0.55±0.15) mm, and 3.25°±1.22°, respectively. With the increase of entry depth, the three-dimensional and depth accuracy of dynamic navigation system decreased (P < 0.01), and the positioning angle deviation had no relation with the entry depth (P>0.01).@*CONCLUSION@#Dynamic navigation technology can achieve high positioning accuracy in the depth range of 15 mm, but its deviation increases with the increase of entry depth.

Reliability of a digital system for models measurements in BBO grading: A pilot study

ABSTRACT Introduction: Currently, no method is considered effective for the evaluation of digital models in the Certification Examination of the Brazilian Board of Orthodontics (BBO), considering the parameters of the currently used manual method. Objective: Thus, the aim of this study is to verify the reliability of an evaluation method for digital models that could be used in the BBO exam, compared to the gold standard. Methods: Measurements were performed by five previously calibrated examiners. Samples of ten sets of plaster models of the final phase of orthodontic treatment were measured using a manual method (Objective Grading System, OGS). These models were digitized using a 3D scanner and exported to Geomagic Qualify software, in which the measurements were made with the proposed digital method. These measurements were repeated using five models, after fifteen days. The intra-examiner performance with this method was analyzed with a paired t-test, whereas the inter-examiner analysis was carried out with analysis of variance and Tukey's test. To compare the manual and digital methods, a paired t-test and Pearson's correlation analysis were performed. Results: A statistically significant difference was found. The results showed that, when compared to the manual method, the digital method was effective in measuring the OGS in four of the seven variables studied: Marginal Ridge, Overjet, Occlusal Contact, and Interproximal Contact. The variables Alignment, BL inclination, and Occlusal Relationship showed a great amount of dispersion in the findings. Conclusion: Further studies are needed to develop an adequate digital methodology that can be used for all OGS variables.

RESUMO Introdução: Ainda não há um método considerado eficaz para análise dos modelos digitais no exame do Board Brasileiro de Ortodontia (BBO), considerando-se os parâmetros do método manual atual. Objetivo: Assim, o presente estudo objetiva verificar a confiabilidade de um método de avaliação em modelos digitais para o exame do BBO, comparando com o padrão-ouro. Métodos: As medições foram realizadas por 5 examinadores, previamente calibrados. A amostra de 10 pares de modelos de gesso da fase final do tratamento ortodôntico foi medida no método manual (Sistema Objetivo de Avaliação, SOA). Os modelos foram digitalizados por meio de um scanner 3D e exportados para o software Geomagic Qualify, onde foram feitas as medidas no método digital proposto. As medidas foram refeitas em 5 modelos após 15 dias. A análise intraexaminador desse método foi realizada por meio do teste t pareado; já a interexaminadores, feita com ANOVA e teste de Tukey, sendo encontrada diferença estatisticamente significativa. Para a comparação dos métodos manual e digital, foram utilizados o teste t pareado e a correlação de Pearson. Resultados: Uma diferença estatisticamente significativa foi encontrada. Os resultados mostraram que, comparada ao método manual, a metodologia digital mostrou-se eficaz para medição do SOA em quatro das sete variáveis estudadas: Margem interproximal, Sobressaliência, Contato oclusal e Contato interproximal. As variáveis Alinhamento, Inclinação V-L e Relação oclusal mostraram muita dispersão nos achados. Conclusão: Mais estudos são necessários para o desenvolvimento de uma metodologia digital adequada em todas as variáveis do SOA.

Dimensional Accuracy Comparison of Physical Models Generated by Digital Impression/3D-Printing or Analog Impression/Plaster Methods

ABSTRACT: This study aimed to compare the trueness and precision of physical models manufactured chairside (intraoral scanner and 3D printed) or by plaster models obtained using impression with alginate or addition silicone. A full- arch stainless steel die was impressed to obtain ten physical models for each group. The models were measured in a stereomicroscope, considering four linear distances. To assess the precision accuracy, an analysis of the measurement variability was carried out, identified by the coefficients of variation and by the Levene's test to compare the groups. To analyze trueness, the data average was subtracted from the database and compared considering alpha as 5 %. Considering precision, the higher dispersion of data occurred in the models obtained with silicone impression. And for trueness, Kruskal Wallis and Dunn tests results did not indicate differences between the groups in the anteroposterior linear distances (p> 0.05). Only in anterior transverse distance obtained through TRIOS (0.31 mm), it presented lower accuracy compared to the models from silicone impression (0.13 mm); however, at transverse posterior distance, the models from silicone impression showed the lowest accuracy (p 0.05). The physical dental models obtained by digital and analog workflows showed acceptable dimensional accuracy expressed by high precision and trueness. There is no difference between the evaluated intraoral scanner systems and the impression materials for the full-arch impression.

RESUMEN: Este estudio tuvo como objetivo comparar la veracidad y precisión de modelos físicos fabricados en la clínica dental (escáner intraoral e impreso en 3D) o por modelos de yeso obtenidos mediante impresión con alginato o silicona de adición. Una matriz de acero inoxidable de arco completo fue impresa para obtener diez modelos físicos para cada grupo. Los modelos se midieron en un estereomicroscopio, considerando cuatro distancias lineales. Se realizó un análisis de la variabilidad de la medida para evaluar la precisión, identificada por los coeficientes de variación y por la prueba de Levene para comparar los grupos. Para analizar la veracidad, el promedio de los datos se restó de la base de datos y se comparó considerando alfa como 5 %. Considerando la precisión, la mayor dispersión de datos ocurrió en los modelos obtenidos con impresión de silicona. Y para la veracidad, los resultados de las pruebas de Kruskal Wallis y Dunn no indicaron diferencias entre los grupos en las distancias lineales anteroposteriores (p> 0,05). Solo en la distancia transversal anterior obtenida mediante TRIOS (0,31 mm) presentó menor precisión en comparación con los modelos de impresión de silicona (0,13 mm); sin embargo, la distancia transversal posterior, los modelos de impresión de silicona mostraron la menor precisión (p 0,05). Los modelos dentales físicos obtenidos mediante flujos de trabajo digitales y analógicos mostraron una precisión dimensional aceptable expresada por alta precisión y veracidad. No se observó diferencia entre los sistemas de escáner intraoral evaluados y los materiales de impresión para la impresión de arco completa.

Usability of free software used for visualization and measurement of digital orthodontic models

The aim of this study was to evaluate the usability of the free software available that allow visualization and measurement of orthodontic digital models. 80 graduate students of orthodontics were asked to perform pre-defined tasks in a digital model through 3D Viewer ® and 3D-Tool ® software. The success in accomplishing the tasks and the time spent were recorded. To end, each participant answered a questionnaire to express their satisfaction regarding the software. There were no statistically significant difference between the software when compared to the accomplishment rates of tasks and the time spent by participants on each one. The software were evaluated as "slightly satisfactory" in several criteria. There is scope for optimization of orthodontic software by manufacturers since lack of their interface usability can discourage orthodontists' adherence to new resources that could provide benefits to their daily routine, even if they are freely available.

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.

Dimensional stability of alginate molds scanned at different storage times / Estabilidade dimensional de moldes de alginato digitalizados em diferentes tempos de armazenamento

ABSTRACT The aim of this study was to evaluate the precision and accuracy of molds made with four commercial brands of alginate scanned at different times using digital model analysis. Eighty molds of a standard Typodont were made using 4 types of alginate (CCC: Cavex Color Change; IA: Identic Alginate; HY5: Hydrogum 5 and JP: Jeltrate Plus). The molds were scanned at four times: immediately (T1), 24h (T2), 72h (T3) and 120h (T4) after molding. Measurements were taken in three dimensions: anteroposterior, transverse and vertical. Significant differences in dimensional changes were noted between the materials over time (p <0.05). Anteroposterior dimensional variation was noted between times, especially for IA and JP. For transverse and vertical variables, a difference was found between the groups, especially at 24 h, 72 h and 120 h. CCC presented significant dimensional shrinkage only at T120 (transverse). IA and JP presented larger dimensional distortions in the vertical measurements. The molding materials used were not dimensionally stable when evaluated after 120 hours of molding. However, such evidence suggests that alginates with longer storage time, such as Cavex Color Change, are more accurate than conventional alginates.

RESUMO O objetivo do presente estudo foi avaliar a precisao e acurácia por meio de análise de modelos digitais de moldes digitalizados obtidos com quatro marcas comerciais de alginato em diferentes tempos. Oitenta moldes de um Typodont padrao foram obtidos utilizando 4 tipos de alginato (CCC: Cavex Color Change; IA: Identic Alginate; HY5: Hydrogum 5 e JP: Jeltrate Plus). Os moldes foram escaneados em quatro tempos: mediatamente (T1), 24h (T2), 72h (T3) e 120h (T4) após a moldagem. As medidas foram feitas em très dimensoes: ântero-posterior, transversal e vertical. Diferenças significativas nas mudanças dimensionais foram observadas entre os materiais ao longo do tempo (p <0,05). Variação dimensional ântero-posterior foi observada entre os tempos, principalmente para IA e JP. Para as variáveis transversal e vertical houve diferenga entre os grupos, principalmente em 24h, 72h e 120h. CCC apresentou contração dimensional significativa apenas em T120 (transversal). IA e JP apresentaram maiores distorções dimensionais na vertical. Os materiais de moldagem utilizados nao foram dimensionalmente estáveis quando avaliados após 120 horas de moldagem. No entanto, tais evidencias sugerem que os alginatos com maior tempo de armazenamento, como Cavex Color Change, sao mais precisos do que os alginatos convencionais.

Precision and accuracy of four current 3D Printers to achieve models for Fixed Dental Prosthesis / Precisão de quatro impressoras 3D para obtenção de modelos para prótese fixa

ABSTRACT The aim of this study was to compare the accuracy and precision of 3D printers used to obtain models of fixed dental prostheses. A fixed dental prosthesis preparation was scanned and reproduced by four 3D printers: RapidShape P40, Asiga MAX, Varseo, and Photon. The impressions were scanned again, and the dataset was compared to the original dataset. Mean discrepancies (μm) were 52.97±20.48 (RapidShape P40), 68.27±43.53 (Asiga MAX), 62.22±56.21 (Varseo), and 80.03±28.67 (Photon). There was no difference (p=0.314) in accuracy; however, the precision differed (p=0.015) among the 3D printers. The printers had distinct precision but did not differ in accuracy.

RESUMO O objetivo desse trabalho foi comparar a acurácia e a precisão de impressoras 3D utilizadas para a obtenção de modelos para prótese fixa. Um preparo para prótese fixa foi escaneado e reproduzido por 4 impressoras 3D: RapidShape 3D, Asiga MAX, Varseo e Photon. As impressões foram novamente escaneadas, e o dataset escaneado foi comparado ao original. Os esca neamentos foram sobrepostos digitalmente e determinada a discrepância entre os modelos original e impresso. A discre pância média (μm) entre os modelos foi de foi 52,97±20,48 (RapidShape 3D), 68,27±43,53 (Asiga MAX), 62,22±56,21 (Varseo) e 80,03±28,67 (Photon). Não houve diferença (p=0,314) entre os valores médios, os quais representam a acurácia; entretanto, o desvio padrão dessas foi diferente (0,015), indicando diferença na precisão das impressoras 3D.

Study on functional occlusal morphology by using three-dimensional printed diagnostic crown and functional generated path technology / 中华口腔医学杂志

Objective@#To establish the functional occlusal morphology of fixed prostheses by using functional generated path (FGP) technology on a three-dimensional-printed diagnostic crown in order to decrease the chance of occlusal adjustment during try-in procedure of the complete crown, and to avoid the risk of occlusal interference after cementation of prosthesis.@*Methods@#A double-blind clinical trial was performed. Ten subjects (4 males, 6 females) who needed a first molar complete crown restoration were enrolled in Department of Prosthodontics, Peking University School and Hospital of Stomatology from July 2018 to December 2018. The working models with the abutment teeth of the ten participants were scanned to obtain the digital models, then the occlusal surfaces of crown were formed by either FGP technology on a three-dimensional (3D) printed diagnostic crown and then were scanned directly for computer aided design and computer aided manufacture (CAD/CAM) crown fabrication as experiment group, or conventional technology based on database as control group. Then zirconia crowns were fabricated for two groups. During crown try-in of the two groups, preferred crowns of subjects were recorded, the occlusal contact criteria including the occlusal contact area (mm2), the heights of occlusal high spot (mm) before and after the adjustment of crowns were digitally analyzed, and the amount of adjustment (mm and mm3) were calculated on digital models by using a reverse engineering software (Giomagic Sudio & Quality). Differences of values were compared statistically with paired t-test (α=0.05).@*Results@#The amount for occlusal adjustment for crowns in the experiment group [(7.320±4.238) mm3] was statistically less than that in the control group [(20.178±9.650) mm3] (P<0.05), the occlusal contact area of experiment group [(11.430±4.102) mm2] was statistically bigger than that of the control group [(4.808±3.223) mm2] (P<0.05), the heights of occlusal high spots for crowns in the experiment group was (0.043±0.019) mm while it was (0.594±0.201) mm in the control group with statistically significant differences (P<0.05).@*Conclusions@#This method could lead to a crown with less adjustment of occlusion, less occlusal high spot and less risk of occlusal interferences.

Three-dimensional printed models versus conventional stone models: an accuracy analysis

Aim: To compare the accuracy (trueness and precision) of cost-accessible three-dimensional (3D) printed models. Methods: A maxillary typodont (MM) was scanned and printed 10 times in polylactic acid, resulting in 10 digital models (DMs). Polyvinylsiloxane impressions were made to obtain 10 conventional stone models (SMs). All models were scanned and imported to CloudCompare software. The total area and three locations of interest were evaluated (zenith to incisal [Z-I], canine to canine [C-C], and first molar to canine [1M-C] distances). Total area evaluations were performed by aligning the MM and experimental models using the best-fit algorithm and were compared using the Haussdorf distance. The distances between points of interest were measured using the point-picking tool at the same 3D coordinates. The mean volumetric deviations were considered for trueness analysis. Precision was set as the standard deviation. Statistical differences were evaluated using the Student's t-test. Results:Total area volumetric comparisons showed that DMs showed superior trueness and precision (-0.02 ± 0.03) compared to the SMs (0.37 ± 0.29) (P < 0.001). No differences between the models were observed for Z-I (P = .155); however, SMs showed fewer deviations for C-C (P = .035) and 1M-C (P = .001) than DMs. Conclusions: The DMs presented superior trueness and precision for total area compared to the SMs; however, the SMs were more accurate when points of interest were evaluated

Comparación estadística entre modelo de yeso, digitalizado e impreso en 3D / Statistic comparison of digitalized plaster models and printed in 3D

Se realizaron mediciones en los ejes x, y, z sobre modelos dentales de yeso, digitalizados e impresos con impresoras 3D, con fines comparativos, estadísticos y evaluativos, cuyo objetivo fue estimar el grado de coincidencia significativa entre los modelos, realizados por dos profesionales, en dos momentos diferentes. Los resultados arrojaron datos de gran precisión en forma y tamaño en los tres estudios, con mínima distorsión (no significativa, p =0,05), lo que determinó la importancia de implementación en forma institucional o privado el estudio digital de los mismos, para realizar comparaciones, mediciones, diagnósticos y acopio de modelos virtuales en un ordenador, siendo estos más precisos y de menor tiempo de trabajo (AU)

Measurements were made in the x, y, z axes on gypsum dental models, digitized and printed with 3D printers, for comparative, statistical and evaluative purposes, whose objective was estimate the degree of significant coincidence between models, that were made by two professionals, at two different times.The results were the achieve of data with a great shape´s and size´s precisionat the three studies, with minimal distortion (not significant, p = 0.05), which determined the importance of the institutional or private way of an implementation of the model´s digital studies, with the aim of doing comparisons, measurements, diagnostics, and collection of virtual models in a computer, to being more precise and with less work time (AU)

The association between palatal rugae pattern and dental malocclusion

ABSTRACT Introduction: Palatal rugae complete its development during early intrauterine life, whereas dental malocclusions in permanent dentition establishes several years into the post-natal life. Objective: The objective of present study was to determine if there is an association between the palatal rugae pattern and Angle's classes of malocclusion. Methods: A cross-sectional study was conducted on pretreatment dental casts of 184 patients. The sample was divided into the following groups: Class I, Class II div. 1, Class II div. 2, and Class III. The number of palatal rugae was recorded, bilaterally. The length, pattern and orientation of three anterior-most primary rugae on both sides were recorded. Results: The mean age of the study sample was 17.8 ± 5.4 years. The mean number of the palatal rugae was 11.18 ± 2.5, with significant differences among different malocclusion groups. The length of the first rugae on left side and third rugae on both sides varied significantly among the groups (p< 0.05). Similarly, the pattern of palatal rugae was also found to be significantly different among the malocclusion groups. The right sided rugae did not have any significant difference in the orientation in different malocclusion groups; however, the left sided rugae showed significant differences among the four malocclusion groups (p< 0.001). Conclusions: The current study showed subtle differences in the palatal rugae pattern among the Angle's classes of malocclusion. Similarly, the length and orientation of some rugae were also found to be significantly different between malocclusion groups.

RESUMO Introdução: as rugas palatinas completam seu desenvolvimento ainda no início da vida intrauterina, enquanto as más oclusões dentárias na dentição permanente se estabelecem após vários anos de vida pós-natal. Objetivos: o presente estudo foi planejado para determinar se há associação entre o padrão das rugas palatinas e as más oclusões, segundo a classificação Angle. Métodos: um estudo transversal foi conduzido a partir dos modelos dentários pré-tratamento de 184 pacientes. A amostra foi dividida em quatro grupos: Classe I; Classe II, divisão 1; Classe II, divisão 2 e Classe III. O número de rugas palatinas foi registrado bilateralmente. O comprimento, padrão e a orientação das três rugas primárias mais anteriores de ambos os lados foram registrados. Resultados: a idade média da amostra desse estudo foi de 17,8 ± 5,4 anos. O número médio de rugas palatinas foi de 11,18 ± 2,5, com diferenças significativas entre os grupos de más oclusões. O comprimento da primeira ruga do lado esquerdo e da terceira ruga em ambos os lados variou significativamente entre os grupos (p< 0,05). De forma semelhante, o padrão das rugas palatinas também mostrou diferença significativa entre os grupos com diferentes má oclusões. As rugas do lado direito não apresentaram nenhuma diferença significativa de orientação nos diferentes grupos; no entanto, as rugas do lado esquerdo apresentaram diferenças significativas nos grupos estudados (p< 0,001). Conclusões: o presente estudo demonstrou diferenças sutis quanto ao padrão das rugas palatinas entre as classes de má oclusão definidas por Angle. Do mesmo modo, o comprimento e a orientação de algumas rugas também se apresentaram consideravelmente diferentes entre os grupos com diferentes má oclusões.

3D comparison of dental arch stability in patients with and without cleft lip and palate after orthodontic/rehabilitative treatment

Abstract This study aimed to compare the linear dimensions of the dental arches of adult patients with complete unilateral cleft lip and palate (UCLP) after orthodontic and prosthetic treatment with fixed partial dentures (FPD) to patients without clefts, using 3D technology. This retrospective longitudinal study sample consisted of 35 subjects divided into two groups. Included in this sample were 15 complete UCLP individuals who had received orthodontic treatment before rehabilitation with a fixed partial denture (FG), as well as 20 patients without cleft as control group (CG). All patients were aged between 18 and 30 years. Digital dental casts were obtained in two stages: (T1) end of orthodontic treatment and (T2) one year after prosthetic rehabilitation (FG); and (T1) end of orthodontic treatment and (T2) one year after removal of the orthodontic appliance (CG). Intercanine, interfirst premolar and intermolar distances, and incisor-molar length were obtained. A precalibrated and trained examiner performed the assessments. Intergroup differences between T2 and T1 were compared between the groups using the t test or Mann-Whitney test with a significance level of 5% (p<0.05). The intercanine distance variation (T2-T1) showed statistical difference (p=0.005) increasing in the FG group and decreasing in the CG group. In the interfirst premolar distance variation, FG decreased, while CG increased with statistically significant difference (p=0.008). The intercanine distance of individuals with cleft showed stability, while that of the CG had no stability. The CG showed stability in the interfirst premolar distance, while FG had no stability. These findings showed that the FPD is capable of restricting orthodontic results, leading to a stabilization of the dental arches.

Three-dimensional comparison of 2 digital models obtained from cone-beam computed tomographic scans of polyvinyl siloxane impressions and plaster models

PURPOSE: This study was performed to evaluate the dimensional accuracy of digital dental models constructed from cone-beam computed tomographic (CBCT) scans of polyvinyl siloxane (PVS) impressions and cast scan models.MATERIALS AND METHODS: A pair of PVS impressions was obtained from 20 subjects and scanned using CBCT (resolution, 0.1 mm). A cast scan model was constructed by scanning the gypsum model using a model scanner. After reconstruction of the digital models, the mesio-distal width of each tooth, inter-canine width, and inter-molar width were measured, and the Bolton ratios were calculated and compared. The 2 models were superimposed and the difference between the models was measured using 3-dimensional analysis.RESULTS: The range of mean error between the cast scan model and the CBCT scan model was −0.15 mm to 0.13 mm in the mesio-distal width of the teeth and 0.03 mm to 0.42 mm in the width analysis. The differences in the Bolton ratios between the cast scan models and CBCT scan models were 0.87 (anterior ratio) and 0.72 (overall ratio), with no significant difference (P>0.05). The mean maxillary and mandibular difference when the cast scan model and the CBCT scan model were superimposed was 53 µm.CONCLUSION: There was no statistically significant difference in most of the measurements. The maximum tooth size difference was 0.15 mm, and the average difference in model overlap was 53 µm. Digital models produced by scanning impressions at a high resolution using CBCT can be used in clinical practice.

Dimensional Stability of Alginates Molds Tridimentionally Scanned / Estabilidade Dimensional de Moldes de Alginatos Escaneados Tridimensionalmente

Alginate is among the most used materials in dentistry to create teeth negative printing and reproduction. The goal of this study was to compare dimensional changes of alginate scanned impression materials. Thirty impressions of a standard typodont were performed using three types of alginate (Hydrogum 5; Jeltrate Plus and Avagel). The impressions were scanned by the scanner 3Shape R700T and scans were performed immediately after molding. The analysis of digital models were performed at OrthoAnalyzer ™ 3D software. Measurements were carried out in relation to the transverse dimension (intercanine, interpremolares and intermolar). Method error was evaluated through the Intraclass Correlation Coefficient (ICC) and Bland-Altman. One-way ANOVA, Dunnet Post-test were used to compare the different groups in relation to Typodont (gold standard) for the different outcome variables. The data were tabulated in Statistical Package for Social Sciences version 20.0 and Minitab 17.0 softwares to compare groups. The significance level was 5%. The posterior transverse variables (D1PM, D2PM and DM) presented a statistically significant difference regarding the gold standard (Typodont) for the plaster models performed after the Avagel molding. In the digital models performed just after molding, only in DM, the Avagel material group presented values statistically higher than the control group. The alginates Hydrogum 5 and Jeltrate Plus presented dimensions closer to the gold standard.(AU).

O alginato está entre os materiais de moldagem mais utilizados na Odontologia para criar impressão e reprodução negativa dos dentes. O objetivo desse trabalho foi comparar alterações transversais de três marcas comerciais de alginato (Hydrogum, Jeltrate e Avagel) em moldes de alginatos. Trinta moldes de um Typodont padrão foram realizados, utilizando três tipos de alginato (Hydrogum 5; Jeltrate Plus e Avagel). Os moldes foram escaneados por meio do scanner 3Shape R700T e os escaneamentos realizados logo após a moldagem e logo após a obtenção dos modelos de gesso. As análises dos modelos digitais foram realizadas no software OrthoAnalyzer™ 3D. Foram realizadas mensurações em relação à discrepância transversal (inter-caninos, inter-primeiro pré-molar, inter-segundo pré-molar e inter-molares). O erro do método foi avaliado por meio do Coeficiente de Correlação Intraclasse (CCI) e Bland-Altman. Utilizou-se Análise de Variância (one-way ANOVA, Pós-teste Dunnet) para comparação dos diferentes grupos em relação ao typodont (padrão-ouro) para as diferentes variáveis de desfecho. A análise estatística foi realizada nos programas Statistical Package for Social Sciences versão 20.0 e no programa Minitab 17.0 para comparação dos grupos. O nível de significância foi de 5%. As variáveis transversais posteriores (D1PM; D2PM e DM) apresentaram diferença estatisticamente significante em relação ao padrão-ouro (manequim) para os modelos de gesso realizados após a moldagem com Avagel. Nos modelos digitais realizados logo após a moldagem, apenas na DM, o grupo do material Avagel apresentou valores estatisticamente maiores do que o grupo controle. Os alginatos Hydrogum 5 e Jeltrate Plus apresentaram dimensões mais próximas do padrão-ouro.(AU).

Os modelos ortodônticos digitais são confiáveis? Uma revisão sistemática / Are the digital orthodontics models reliable? A systematic review

Introdução: Os modelos ortodônticos digitais são alternativas ao uso de modelos ortodônticos em gesso. Devido sua importância no diagnóstico, faz-se necessário averiguar a precisão dos softwares de modelos ortodônticos digitais disponíveis no mercado. Objetivo: Evidenciar qual software de modelos ortodônticos digitais possui maior confiabilidade. Material e métodos: Foi realizada busca sistemática nas seguintes bases de dados eletrônicas: Scopus, PubMed, Web of Science, Embase e Cochrane, Grey Literature e Clinical Trials, sem limitações quanto ao ano de publicação ou idioma. Foram incluídos estudos laboratoriais que utilizaram softwares destinados a geração de modelos ortodônticos digitais, comparando-os com modelos ortodônticos em gesso. Após seleção por título e resumo, os artigos potencialmente elegíveis foram lidos na íntegra. A qualidade metodológica e o risco de viés dos artigos incluídos foram avaliados de acordo com as descrições dos modelos, técnicas de medição e análises estatísticas. A qualidade metodológica foi classificada em alta, moderada ou baixa. Resultados: 13.333 artigos foram encontrados nas bases de dados utilizadas. Após a aplicação dos critérios de elegibilidade e remoção de duplicações, restaram apenas 41 artigos. 29 foram considerados de qualidade moderada e 12 de alta qualidade. A classificação quanto à confiabilidade variou de menos confiaveis, equivalentes e a mais confiaveis. Apresentando diferenças estatisticas em suas mensurações (p<0,05); sem significância clínica. Conclusão: os modelos ortodônticos digitais apresentaram mensurações acuradas, reprodutíveis e confiáveis quando comparado ao método convencional utilizando modelos de gesso.

Introduction: Digital models are an alternative for the use of orthodontic models in plaster. Due to its importance in the orthodontic dignified, it is necessary to ascertain the accuracy of the software of digital orthodontic models available in the market. Objective: To show which software of digital orthodontic models has greater reliability. Material and methods: A systematic search was performed in the following electronic databases: Scopus, PubMed, Web of Science, Embase and Cochrane, Gray Literature and Clinical Trials, with no limitations on year of publication or language. We included laboratory studies using digital orthodontic models, comparing them with orthodontic models of plaster through the evaluation of reliability through measurement techniques. After selection by title and abstract, potentially eligible articles have been read in full. The methodological quality and risk of bias of the included articles were evaluated according to the descriptions of the models, measurement techniques and statistical analyzes. The methodological quality was classified as high, moderate or low. Results: 13,333 articles were found in the databases used. After applying the eligibility criteria and removing duplicates, only 41 articles remained. 29 were considered of moderate quality and 12 of high quality. The ranking of digital models for reliability ranged from less reliable, equivalent, and more reliable. Presenting statistical differences in their measurements (p <0.05), without clinical significance. Conclusion: The measurements made in digital models can be as accurate, reproducible and reliable as the conventional method using plaster models.