From medical imaging to 3D printed anatomical models: a low-cost, affordable 3D printing approach.

OBJECTIVE: To share our experience in creating precise anatomical models using available open-source software. METHODS: An affordable method is presented, where from a DICOM format of a computed tomography, a segmentation of the region of interest is achieved. The image is then processed for surface improvement and the DICOM format is converted to STL. Error correction is achieved and the model is optimized to be printed by stereolithography with a desktop 3D printer. RESULTS: Precise measurements of the dimensions of the DICOM file (CT), the STL file, and the printed model (3D) were carried out. For the C6 vertebra, the dimensions of the horizontal axis were 55.3 mm (CT), 55.337 mm (STL), and 55.3183 mm (3D). The dimensions of the vertebral body were 14.2 mm (CT), 14.551 mm (STL), and 14.8159 mm (3D). The length of the spinous process was 18.2 mm (CT), 18.283 mm (STL), and 18.2266 mm (3D), while its width was 8.5 mm (CT), 8.3644 mm (STL), and 8.3226 mm (3D). For the C7 vertebra, the dimensions of the horizontal axis were 58.6 mm (CT), 58.739 mm (STL), and 58.7144 mm (3D). The dimensions of the vertebral body were 14 mm (CT), 14.0255 mm (STL), and 14.2312 mm (3D). The length of the spinous process was 18.7 mm (CT), 18.79 mm (STL), and 18.6458 mm (3D), and its width was 8.9 mm (CT), 8.988 mm (STL), and 8.9760 mm (3D). CONCLUSION: The printing of a 3D model of bone tissue using this algorithm is a viable, useful option with high precision.

OBJETIVO: Compartir nuestra experiencia para crear modelos anatómicos precisos utilizando software con licencia abierta disponibles. MÉTODOS: Se presenta un método asequible, en donde a partir de un formato DICOM de una tomografía computarizada se logra una segmentación de la región de interés. Posteriormente se procesa la imagen para una mejora de superficie y se realiza la conversión de formato DICOM a STL. Se logra la corrección de errores y se optimiza el modelo para luego ser impreso por medio de estereolitografía con una impresora 3D de escritorio. RESULTADOS: Se efectuaron mediciones precisas de las dimensiones del archivo DICOM (TC), del archivo STL y del modelo impreso (3D). Para la vértebra C6, las dimensiones del eje horizontal fueron 55.3 mm (TC), 55.337 mm (STL) y 55.3183 mm (3D). Las dimensiones del cuerpo vertebral fueron 14.2 mm (TC), 14.551 mm (STL) y 14.8159 mm (3D). La longitud de la apófisis espinosa fue de 18.2 mm (TC), 18.283 mm (STL) y 18.2266 mm (3D), mientras que su ancho fue de 8.5 mm (TC), 8.3644 mm (STL) y 8.3226 mm (3D). Para la vértebra C7, las dimensiones del eje horizontal fueron 58.6 mm (TC), 58.739 mm (STL) y 58.7144 mm (3D). Las dimensiones del cuerpo vertebral fueron 14 mm (TC), 14.0255 mm (STL) y 14.2312 mm (3D). La longitud de la apófisis espinosa fue de 18.7 mm (TC), 18.79 mm (STL) y 18.6458 mm (3D), y su ancho fue de 8.9 mm (TC), 8.988 mm (STL) y 8.9760 mm (3D). CONCLUSIÓN: La impresión de un modelo en 3D de tejido óseo mediante este algoritmo resulta una opción viable, útil y con una alta precisión.

Accuracy of dental implants positioning in computer-assisted surgeries: In vitro study.

OBJECTIVES: The aim of this study is to presents an experimental method for surgical guide confection using an intraoral scanner to obtain a 3D model of the patient's complete denture and compare its accuracy with the conventional methodology using computed tomography. STUDY DESIGN: This prospective in-vitro study used 30 polyurethane pre-manufactured mandibles which were divided into two groups, conventional technique (group I) and a new method using intraoral scanner (group II), establishing the virtually planned position of the dental implants as a control group, considered as the gold standard for postoperative comparison. RESULTS: The difference between these methods is close to zero and not statistically significant (p > 0.05), being heigh deviation (Xh) with p:0.130 and angulation difference of dental implants between the groups (Ang) with p:0.396. CONCLUSION: The acquisition of stereolithography image of the prosthesis using an intraoral scanner has a clinically acceptable accuracy, being in agreement with the conventional method.

Influence of the postpolymerization type and time on the flexural strength and dimensional stability of 3D printed interim resins.

STATEMENT OF PROBLEM: The mechanical strength of 3-dimensionally (3D) printed interim resins is unclear but influenced by printing parameters. Evidence regarding standardization of the postpolymerization type and time for 3D printed interim resins is sparse. PURPOSE: The purpose of this in vitro study was to evaluate the influence of postpolymerization type and time on flexural strength and dimensional stability of 3D printed resins for interim restorations. MATERIAL AND METHODS: A total of 288 bars were 3D printed (Form 2; Formlabs, stereolithography-SLA, 50 µm, 30 degrees), (25×2×2 mm; International Organization for Standardization-ISO 4049:2019) abraded and randomly divided into 9 groups (n=30) according to postpolymerization (Ultraviolet device-UV; Microwave with water-MWA; Microwave without water-MW) and time (15, 20, and 30 minutes for UV; and 5, 8, and 10 minutes for MW and MWA). Each bar was then measured with digital calipers at 11 points for length, thickness, and width before and after postpolymerization to analyze dimensional stability. The flexural strength was then measured (σ; 980.6 N, 1 mm/minute) and the fractured surfaces were analyzed with scanning electron microscopy. The σ (MPa) data were evaluated by using a 2-way analysis of variance (ANOVA) and the Tukey honestly significant difference (HSD) pairwise comparisons test (α=.05). Dimensional stability data (mm) were analyzed by using the Kruskal-Wallis test and Dwass-Steel-Critchlow-Fligner multiple comparisons. The Weibull analysis was performed with σ data. RESULTS: The 2-way ANOVA revealed that all factors and their interaction were significant for σ (P<.001). The UV groups presented the highest σ values, being statistically higher than all MW and MWA groups. The Weibull analysis revealed that postpolymerization UV groups found the highest values regarding the characteristic strength, although the MW 8-minute group (13.71) found the highest value for the Weibull modulus. Furthermore, the Kruskal-Wallis test revealed that only the postpolymerization factor was significant for dimensional stability (P<.001). The postpolymerization microwave groups found greater expansion variations at all times, with the MW 8-minute group (0.78 ±0.54) presenting the greatest variation in dimensional stability. CONCLUSIONS: UV was determined to be the most suitable type of postpolymerization for interim printed resin among the postpolymerization methods, regardless of the application time. The postpolymerization MW groups found greater variations in dimensional stability.

Cost and effectiveness of 3-dimensionally printed model using three different printing layer parameters and two resins.

STATEMENT OF PROBLEM: When 3-dimensional printing casts, the operator can change the type of resin and the printing layer thickness, reducing the fabrication time. However, how these parameters affect the accuracy of 3-dimensionally printed casts is unknown. PURPOSE: The purpose of this in vitro study was to evaluate the accuracy of 3-dimensionally printed casts by using a stereolithography (SLA) 3-dimensional printer (Forms2) with 3 different layer thickness (25, 50, and 100 µm) and 2 different resins (Gray and Cast) and by comparing the time to obtain each cast. MATERIAL AND METHODS: One master cast was scanned, and a single file was printed several times. The printed casts were then scanned by using a laboratory scanner. The standard tessellation language (STL) files provided by the laboratory scanner were superimposed and compared by using a software program (Geomagic Control; 3D Systems). The 2-way ANOVA test was used for the trueness evaluation, followed by the Tukey test to identify differences among the groups (α=.05). RESULTS: No statistically significant differences in accuracy were found among the 3 different layers for either resin (P>.05). Printing time doubled as layer thickness decreased. CONCLUSIONS: This study showed that when printing casts, the fastest printing settings can be used without losing accuracy and that the laboratory digital workflow can be accelerated with selection of the resin and cast layer, as the type of resin and layer thickness did not influence the quality of the casts.

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)

Accuracy of Dental and Industrial 3D Printers.

PURPOSE: This in vitro study evaluated the dimensional accuracy of three 3D printers and one milling machine with their respective polymeric materials using a simplified geometrical model. MATERIALS AND METHODS: A simplified computer-aided design (CAD) model was created. The test samples were fabricated with three 3D printers: a dental desktop stereolithography (SLA) printer, an industrial SLA printer, and an industrial fused deposition modeling (FDM) printer, as well as a 5-axis milling machine. One polymer material was used per industrial printer and milling machine while two materials were used with the dental printer for a total of five study groups. Test specimens were then digitized using a laboratory scanner. The virtual outer caliper method was used to measure the linear dimensions of the digitized 3D printed and milled specimens in x-, y-, and z-axes, and compare them to the known values of the CAD model. Data were analyzed with Kruskal-Wallis one-way ANOVA on Ranks followed by the Tukey's test. RESULTS: Milled specimens were not significantly different from the CAD model in any dimension (p > 0.05). All 3D printed specimens were significantly different from the CAD model in all dimensions (p = 0.01), except the dental SLA 3D printer with one of the polymers tested (Bis-GMA) which was not significantly different in two (x and z) dimensions (p = 0.4 and p = 0.12). CONCLUSIONS: The milling technology tested provided greater dimensional accuracy than the selected 3D printing. Printer, printing technology, and material selection affected the accuracy of the printed model.

Aplicações da manufatura aditiva em oftalmologia / Applications of additive manufacturing in ophthalmology

RESUMO A manufatura aditiva, mais popularmente conhecida como impressão tridimensional, baseia-se no desenvolvimento de um objeto com a ajuda de um software de desenho assistido por computador seguido de sua impressão por meio da deposição de uma matéria-prima, camada por camada, para a construção do produto desejado. Existem vários tipos de técnicas de impressão tridimensional, e o tipo de processo de impressão escolhido depende da aplicação específica do objeto a ser desenvolvido, dos materiais a serem utilizados e da resolução necessária à impressão do produto final. A impressão tridimensional abriu perspectivas na pesquisa e revolucionou o campo das ciências da saúde, com a possibilidade de criação e de desenvolvimento de produtos personalizados de maneira rápida, econômica e de forma mais centralizada do que no processo de manufatura tradicional. As tecnologias de manufatura aditiva remodelaram os diagnósticos médicos; as medidas preventivas e pré-operatórias; o tratamento e a reabilitação, assim como os processos de engenharia de tecidos nos últimos anos. Na oftalmologia, as aplicações da impressão tridimensional são extensas. Modelos anatômicos para aplicação na área da educação e planejamentos cirúrgicos, desenvolvimento de implantes, lentes, equipamentos para diagnósticos, novas aplicações terapêuticas e desenvolvimento de tecidos oculares já estão em desenvolvimento. Por possuir um campo amplo e ser alvo de pesquisa constante, a área oftalmológica permite que a manufatura aditiva ainda seja amplamente utilizada a favor dos médicos e dos pacientes.

ABSTRACT Additive manufacturing, more popularly known as three-dimensional (3D) printing, is based on the development of an object with the help of computer-aided design software followed by its printing through the deposition of a material, layer by layer, to create the desired product. There are several types of 3D printing techniques and the type of printing process chosen depends on the specific application of the object to be developed, the materials to be used, and the resolution required to print the final product. 3D printing has brought new perspectives to research and revolutionized the field of health sciences, with the possibility of creating and developing customized products in a faster, more economical, and more centralized way than in the traditional manufacturing process. Additive manufacturing technologies have reformulated medical diagnostics, preventive, preoperative, treatment, and rehabilitation, as well as tissue engineering processes in recent years. In ophthalmology, the applications of 3D printing are extensive. Anatomical models for application in education and surgical planning, development of implants, lenses, diagnostic equipment, new therapeutic applications, and development of ocular tissues (3D bioprinting) are already under development. As it has a wide field and is the subject of constant research, the ophthalmic area allows additive manufacturing to still be widely used in favor of doctors and patients.

Desmistificando o uso da impressora 3D / Demystifying the use of the 3D printer

Resumo Apesar de diversas empresas oferecerem o serviço de confecção de alinhadores transparentes, a aquisição de uma impressora 3D gera ao ortodontista a possibilidade de não depender exclusivamente das mesmas. Além disso, o profissional que domina a produção de alinhadores consegue diminuir os custos, individualizar sua confecção de acordo com as necessidades do paciente, podendo planejar os casos com diferentes attachments, utilizando placas com diferentes espessuras e/ou recortes e ainda selecionar a resina mais adequada para impressão. Porém, ainda existem dúvidas com relação à utilização e aquisição de uma impressora 3D, fazendo com que os profissionais se sintam inseguros na decisão de adquiri-la. Dessa forma, visando facilitar a aquisição e utilização rotineira de uma impressora 3D, objetiva-se detalhar o passo a passo para a obtenção de um modelo 3D, descrevendo pontos importantes que devem ser avaliados quando pretende-se adquirir uma impressora 3D. Diante das diferentes tecnologias disponíveis no mercado, a estereolitografia se destaca para a confecção de alinhadores. A marca Anycubic disponibiliza opções de impressoras 3D a um excelente custo/ benefício. Pôde-se demonstrar que a utilização de uma impressora 3D para confecção de alinhadores é viável e acessível para o ortodontista, devendo o mesmo definir inicialmente o espaço disponível para os equipamentos, a quantidade de modelos que pretende imprimir e o valor que pretende investir. (AU)

Abstract Although several companies offer the service of producing clear aligners, the acquisition of a 3D printer gives the orthodontist the possibility of not depending exclusively on them. In addition, the professional who masters the production of aligners is able to reduce costs, individualize their manufacture according to the patient's needs, be able to plan cases with different attachments, use plates with different thicknesses and/or cutouts, and also select the resin most suitable for printing. However, there are still doubts regarding the use and acquisition of a 3D printer, making professionals feel insecure in the decision to acquire it. Thus, in order to facilitate the acquisition and routine use of a 3D printer, the goal of this article is to detail, step by step, how to obtain a 3D model, describing important points that must be evaluated when purchasing a 3D printer. Given the different technologies available on the market, stereolithography is the most suitable for producing aligners. The Anycubic brand offers 3D printer options at an excellent cost/benefit. It can be observed that the use of a 3D printer for producing aligners is viable and affordable for the orthodontist, who should initially define the space available for the equipment, the number of models that he intends to print, and the amount he intends to invest. (AU)

Una nueva alternativa para la localización y la recuperación de agujas fracturadas durante la anestesia odontológica. Presentación de técnica y caso clínico / A new alternative for locating and removing a needle fractured during dental anesthesia. Technique and case report

Objetivo: Describir en un caso clínico una nueva técni- ca para la localización y la remoción de agujas fracturadas du- rante la anestesia odontológica mediante planificación virtual. Caso clínico: Una paciente de género femenino de 52 años de edad concurre a la Cátedra de Cirugía y Traumatolo- gía Bucomaxilofacial I de la Facultad de Odontología de la Universidad de Buenos Aires y relata que dos meses atrás, durante la atención odontológica, se produjo la fractura de la aguja durante la anestesia troncular mandibular. Se realiza diagnóstico y planificación virtual para conocer la ubicación exacta de la aguja y se confecciona un modelo estereolito- gráfico y una guía quirúrgica individualizada para removerla. El uso de una guía quirúrgica individualizada y confeccio- nada mediante planificación virtual permitió ubicar la aguja tridimensionalmente y con mayor precisión en espacios pro- fundos y disminuir tiempos operatorios (AU)

Aim: To describe in a clinical case a new virtual plan- ning technique for locating and removing a fractured dental anesthetic needle. Clinical case: A 52-year-old patient visited the De- partment of Oral and Maxillofacial Surgery I (School of Dentistry, University of Buenos Aires) with a retained den- tal needle in the pterygomandibular space. The needle had fractured during inferior alveolar nerve block two months previously. Virtual diagnosis and planning were performed to locate the needle and a stereolithographic model and a customized surgical guide were prepared. The use of cus- tomized surgical guides prepared by virtual planning ena- bled precise location of the dental needle in deep spaces and reduced operating times (AU)

Reconstrucción de Fracturas Orbitarias Utilizando Tecnología Digital Tridimensional: Una forma de Optimizar Resultados / Orbital Fracture Reconstruction Using Digital Three-Dimensional Technology: A Way to Optimize Results

La reconstrucción de las paredes orbitarias fracturadas es compleja debido a la gran cantidad de parámetros volumétricos que posee. Una restitución inadecuada de ellas habitualmente está asociada a secuelas postquirúrgicas en el paciente. El contar con herramientas que optimicen la restitución de la forma anatómica de la órbita en su reconstrucción es de vital importancia, y la utilización de nuevas tecnologías ha permitido mejorar los resultados quirúrgicos, tanto anatómicos como funcionales. El objetivo de este artículo es mostrar dos herramientas quirúrgicas que permiten optimizar los resultados terapéuticos en pacientes con fractura de órbita, que son el modelo estereolitográfico con imagen en espejo y la tomografía computada intraoperatoria. Se presentan las características de estas herramientas, su utilización en tres casos de pacientes con fractura orbitaria y los resultados obtenidos en el post operatorio.

The reconstruction of fractured orbital walls is complex due to the many volumetric parameters involved. An inadequate restitution of these walls may be associated with postsurgical sequelae in the patient. Is vitally important to count with tools that optimize the restitution of the orbit's anatomic shape during its reconstruction, and the use of new technologies has allowed the improvement of the surgical results, both anatomical and functional. The aim of this article is to show two surgical tools that allow to optimize the therapeutic results in patients with orbital fracture, which are stereolithographic models with mirror image technique, and intraoperative computed tomography. Their characteristics, their use in three cases of patients with orbital fractures, and the postoperative results are shown.

Impresión 3D de modelos estereolitográficos con protocolo abierto / 3D Printing of Stereolithographic Models with Open Protocol

RESUMEN: Se realizó un estudio descriptivo y exploratorio con el objetivo de proponer y validar un protocolo abierto para hacer impresiones 3D de modelos estereolitográficos, que esté a disposición de profesionales en el área de la Odontología. Se capacitó mediante sesiones teórico prácticas, a nueve personas operadoras (estudiantes de último año de la carrera de Odontología), sin previa experiencia en el uso de software y hardware para impresión 3D, divididos en dos grupos; el A trabajó con tres tomografías helicoidales (TAC) y el B con tres Tomografías Computarizadas de Haz Cónico (CBCT), todas en formato DICOM, convertidas en archivos STL. En total se aplicó el protocolo en 99 estructuras óseas correspondientes a 33 mandíbulas, 33 axis y 33 macizos faciales-bases de cráneo, y se imprimieron un total de 33 mandíbulas en filamento PLA (ácido poliláctico). Al finalizar el estudio, no se encontró diferencia estadísticamente significativa en la implementación del protocolo propuesto entre los operadores, las mediciones de las piezas impresas por cada uno de ellos, el patrón de oro, la TAC y el CBCT, con lo cual no solo se validó el protocolo, sino que se logró determinar los recursos necesarios para realizar este tipo de impresiones 3D.

ABSTRACT: A descriptive and exploratory study was carried out with the aim of proposing and validating an open protocol for making 3D impressions of stereolithographic models, which is available to professionals in the area of Dentistry. Nine operators (senior students of the Dentistry degree), without previous experience in the use of software and hardware for 3D printing, divided into two groups were trained through theoretical and practical sessions. The A worked with three helical tomographies (TAC) and the B with three cone beam computed tomography (CBCT), all in DICOM format, converted to STL files. In total, 99 bone structures corresponding to 33 jaws, 33 axis and 33 facial masses-skull bases were analyzed, and a total of 33 jaws were printed in PLA (polylactic acid filament). At the end of the study, no statistically significant difference was found in the implementation of the proposed protocol between the operators, the measurements of the pieces printed by each of them, the gold standard, the TAC and the CBCT, with which not only validated the protocol, but it was possible to determine the resources necessary to carry out this type of 3D printing.

Influences of build angle on the accuracy, printing time, and material consumption of additively manufactured surgical templates.

STATEMENT OF PROBLEM: Although desktop stereolithography (SLA) 3D printers and photopolymerizing resin have been used increasingly in dentistry to manufacture surgical templates, studies investigating their clinical application are lacking. PURPOSE: The purpose of this in vitro study was to evaluate the effects of build angle on the accuracy, printing time, and material consumption of additively manufactured surgical templates made with a desktop SLA 3D printer and photopolymerizing resin material. MATERIAL AND METHODS: Fifty surgical templates were fabricated from 1 master digital design file using a desktop SLA 3D printer and photopolymerizing resin material at 5 different build angles (0, 30, 45, 60, and 90 degrees) (n=10). All surgical templates were digitized and superimposed with the master design file using best-fit alignment in the surface matching software program. Dimensional differences between the sample files and the original master design files were compared, and the mean deviations were measured in the root mean square (measured in mm, representing accuracy). The printing time and resin consumption for each specimen were recorded based on the information in the 3D printing preparation software program. ANOVA and the Fisher least significant difference (LSD) test were used to estimate the effects of build angles on the root mean square, printing time, and resin consumption (α=.05 for all tests). RESULTS: The groups 0 degree (0.048 ±0.007 mm) and 45 degrees (0.053 ±0.012 mm) had statistically significant lower root mean square values when compared with those of groups 30 degrees (0.067 ±0.009 mm), 60 degrees (0.079 ±0.016 mm), and 90 degrees (0.097 ±0.017 mm) (P<.001 for all comparisons, except P=.003 for groups 30 degrees versus 45 degrees). The group 90 degrees had statistically significant higher root mean square values than all other groups (P<.001 for all comparisons, except P=.010 when compared with the group 60 degrees). For the printing time, the group 0 degree required significantly less printing time than all other groups (hour:minute, 1:26 ±0:03, P<.001 for all comparisons). The group 90 degrees required significantly more printing time than all other groups (2:52 ±0:06, P<.001 for all comparisons). For resin consumption, the groups 0 degree (11.58 ±0.21 mL), 30 degrees (11.32 ±0.16 mL), and 45 degrees (11.23 ±0.16 mL) consumed similar amounts of resin. However, there was statistical significance between groups 0 degree and 45 degrees (P=.016). The group 90 degrees consumed the significantly least amount of resin (9.86 ±0.40 mL, P<.001 for all comparisons). CONCLUSIONS: With a desktop SLA 3D printer, the 0-degree and 45-degree build angles produced the most accurate surgical template, and the 90-degree build angle produced the least accurate surgical template. The 0-degree build angle required the shortest printing time but consumed the most resin in the printing process. The 90-degree build angle required the longest printing time but consumed the least amount of resin in the printing process.

Propriedades de superfície e colonização microbiológica de fotopolímero aplicado à manufatura aditiva por estereolitografia a laser / Surface properties and microbiological colonization of photopolymer applied to additive manufacturing by laser stereolithography

O presente estudo teve como objetivo avaliar, in vitro, as propriedades de superfície, colonização microbiológica e atividade antifúngica e antimicrobiana de espécimes confeccionados a partir de fotopolímeros para manufatura aditiva e resina acrílica autopolimerizante. A amostra foi composta por um total de 315 corpos de prova, alocados em três grupos (n=105): grupo controle (GC), confeccionado em acrílico autopolimerizante; e grupos experimentais constituídos por fotopolímeros de impressão 3D nas resoluções de 50µm (GE ­ 50) e 100µm (GE ­ 100). As características e rugosidade de superfície foram avaliadas através de microscópio eletrônico de varredura (MEV) e rugosímetro óptico, respectivamente. A análise microbiológica foi realizada, em triplicata, a partir dos parâmetros de biomassa, matriz extracelular e atividade metabólica do biofilme formado pelos microrganismos Streptococcus mutans e Candida albicans. Em seguida, a atividade antifúngica e antimicrobiana do fotopolímero em seu estado líquido, não polimerizado, foi avaliada durante o período de 48 horas pós incubação. A análise estatística foi realizada no programa SPSS por meio da análise de variância (ANOVA) seguida dos pós testes de Tukey e Dunnett (=0,05). A análise das ultramicrografias, obtidas em MEV, mostraram uma superfície mais irregular nos grupos experimentais (GE-50 e GE-100). Os resultados da análise de rugosidade superficial indicaram que o GC se apresentou menor rugosidade superficial em relação a ambos os grupos experimentais, porém quanto a R3z, houve diferença significativa apenas entre os grupos GC e GE-100 (P<0,05). O GC apresentou maior produção de biomassa e matriz extracelular tanto para S. mutans quanto para C. albicans (P<0,05). Observou-se, também, maior atividade metabólica no GC para S mutans (P<0,05). Não houve diferença dos grupos experimentais entre si (P>0,05). A resina para manufatura aditiva utilizada neste estudo demonstrou potencial para inibir o crescimento microbiano em seu estado líquido não diluído, por um período de 48h. Embora resinas para manufatura aditiva impressas em resoluções de 50 e 100µm apresentem maior rugosidade superficial e alterações de superfície, apontam menor crescimento microbiológico quando comparadas à resina autopolimerizante, indicando potencial antimicrobiano das resinas para manufatura aditiva. (AU)

This study aimed to evaluate, in vitro, the surface properties, microbiological colonization and antifungal and antimicrobial activity of specimens made from photopolymers for additive manufacturing and self- curing acrylic resin. The sample consisted of a total of 315 specimens, divided into three groups (n=105): control group (CG), made of self-curing acrylic; and experimental groups consisting of 3D printing photopolymers at resolutions of 50µm (GE ­ 50) and 100µm (GE ­ 100). Surface characteristics and roughness were evaluated using a scanning electron microscope (SEM) and optical rugosimeter, respectively. The microbiological analysis was performed, in triplicate, from the parameters of biomass, extracellular matrix and metabolic activity of the biofilm formed by the microorganisms Streptococcus mutans and Candidaalbicans. Then, the antifungal and antimicrobial activity of the photopolymer in its liquid, unpolymerized state was evaluated during a period of 48 hours after incubation. Statistical analysis was performed using the SPSS program using analysis of variance (ANOVA) followed by Tukey and Dunnett post tests ( =0.05). The analysis of ultramicrographs, obtained by SEM, showed a more irregular surface in the experimental groups (GE-50 and GE-100). The results of the analysis of surface roughness indicated that the GC had lower surface roughness in relation to both experimental groups, but as for R3z, there was a significant difference only between the GC and GE- 100 groups (P<0.05). The GC showed higher biomass and extracellular matrix production for both S. mutans and C. albicans (P<0.05). A higher metabolic activity was also observed in the GC for S mutans (P<0.05). There was no difference between the experimental groups (P>0.05). The additive manufacturing resin used in this study demonstrated the potential to inhibit microbial growth in its undiluted liquid state for a period of 48 hours. Although resins for additive manufacturing printed at resolutions of 50 and 100µm have greater surface roughness and surface alterations, they point to lower microbiological growth when compared to self-curing resin, indicating an antimicrobial potential of resins for additive manufacturing. (AU)

ULTRA Tomografia Computadorizada Multidetectores com ultra baixa dose de radiação e impressão 3D como auxiliares para cirurgia guiada em implantodontia / Ultra-low dose Multidetector CT and 3D printing as aids to guided implant surgery

Objetivo: relatar um caso clínico de reabilitação com implante dentário imediato realizado utilizando Tomografia Computadorizada Multidetectores (TCMD) com ultra baixa dose de radiação, software de código aberto para manipulação das imagens e impressão 3D de baixo custo do guia cirúrgico. Relato de caso: paciente, sexo masculino, 50 anos de idade, foi avaliado clinicamente relatando dor na região do dente 45, com suspeita de fratura radicular. Como complemento ao exame clínico, o paciente realizou TCMD com ultra baixa dose de radiação para avaliar a condição dentária e do tecido ósseo adjacente. Tendo sido diagnosticada fratura radicular vertical, procedeu-se ao planejamento virtual do implante e à confecção do guia cirúrgico. As imagens em formato DICOM da TCMD foram convertidas para formato STL (Stereolithography) para manipulação e confecção do guia cirúrgico virtual. Esse guia foi impresso em PLA (poliácido láctico) utilizando impressora 3D pelo método FDM (Fusão e Deposição de Material). Após a exodontia atraumática, o guia cirúrgico foi posicionado nos dentes adjacentes e o implante foi inserido. Clinicamente, o paciente encontra-se assintomático, o implante sem sinais clínicos de inflamação e a prótese em função. Uma segunda tomografia do paciente permitiu comparar de forma tridimensional a posição final do implante e o planejamento virtual, que se mostraram equivalentes. Considerações finais: a impressão 3D em PLA mostrou-se uma solução com custo acessível para a produção de guias cirúrgicos, fornecendo previsibilidade e segurança ao implantodontista.(AU)

Objective: to report a clinical case of rehabilitation with dental implant performed using ultra- -low dose Multidetector Computed Tomography (MDCT), open source software for image manipulation, and low cost 3D printing of the surgical guide. Case report: a 50-year-old male patient was clinically evaluated complaining of pain in the tooth 45, and a root fracture was suspected. As a complement to the clinical examination, the patient performed an ultra-low dose MDCT to assess the dental condition and the adjacent bone tissue. A vertical root fracture was diagnosed, and then the virtual planning of the implant and preparation of the surgical guide were performed. The DICOM images from the MDCT were converted into STL (Stereolithography) format for manipulation and confection of the virtual surgical guide. The surgical guide was printed on PLA using a 3D printer by the FDM (Fused Deposition Modeling) method. After atraumatic extraction, the surgical guide was placed in the adjacent teeth and the implant was inserted. Clinically, the patient is asymptomatic, the implant has no clinical signs of inflammation, and the prosthesis is in function. A second ultra- -low dose MDCT of the patient allowed a three-dimensional comparison of the final position of the implant and the virtual planning, which were shown to be equivalent. Final considerations: 3D PLA printing has proved to be an affordable solution for the production of surgical guides, providing predictability and safety for the implantologist.(AU)

Custo-benefício de diferentes impressoras 3D na Ortodontia / Cost-benefit of different 3d printers in orthodontics

Ao escolher uma impressora 3D para modelos odontológicos, a relação custo-benefício deve ser avaliada. Os modelos impressos devem ser acurados, precisos e eficientes quanto ao tempo, assim como financeiramente acessíveis. O objetivo deste estudo é comparar a acurácia, precisão, custo e tempo necessário para a preparação e impressão de modelos usando diferentes tecnologias: duas impressoras DLP (Digital Light Processing) e uma FFF (Fused Filament Fabrication) comparadas ao padrão-ouro (PolyJet). Para realização deste estudo, foram selecionados 10 escaneamentos de 5 pacientes, contendo a arcada superior e inferior. Todos os 10 modelos foram impressos usando a seguinte combinação de tecnologias: (1) DLP Moonray (MR), (2) DLP Anycubic (AC) (3) DLP Moonray com utilização de resina da Anycubic (MRA), (4) filamento UpMini 2 (FFF) e (5) PolyJet Eden 500 da Objet (PJ). Um dos modelos virtuais foi impresso adicionalmente quatro vezes consecutivas em cada impressora, de forma a permitir a avaliação da precisão destas. O arquivo .STL original de cada modelo foi superposto com o escaneamento do seu respectivo modelo impresso, gerando mapas de cores que permitiram o cálculo de RMS (média quadrática) para a comparação de ambos. Além deste método, foram realizadas medidas lineares através de um paquímetro digital em 8 variáveis diferentes: distância inter-caninos (DIC), distância inter-molares (DIM), plano ântero-posterior bilateralmente (PAP-D e PAP-E), plano vertical bilateralmente (PV-D e PV-E) e plano misto bilateralmente (PM-D e PM-E). O teste Shapiro-Wilk mostrou que os dados não eram normalmente distribuídos. O teste de Friedman com o post hoc de Bonferroni foi utilizado para verificar se havia diferenças entre os valores obtidos para as variáveis avaliadas. Uma diferença acima de 0,4 mm foi considerada clinicamente significante para as medidas lineares. Observou-se diferenças clínica e estatisticamente significantes (p < 0,05) para as seguintes comparações: PV-D e PV-E entre MR e MRA (p=0,00), PV-D entre FFF e MR (p=0,01), e PV-E entre FFF e MR (p=0,00). Já para o RMS, ocorreram diferenças estatisticamente significantes entre: AC e MR (p=0,00); AC e MRA (p=0,00); FFF e MR (p=0,01) e PJ e MR (p=0,01). Para as diferenças no RMS, nenhum valor esteve acima do considerado clinicamente significante (0,25 mm). Quando avaliada a precisão dos modelos pelas medidas lineares, observou-se diferença estatisticamente significativa apenas na variável PV-D entre FFF e AC (p=0,00). A mesma diferença foi vista para os valores de RMS em: AC e MR (p=0,02) e AC e MRA (p=0,04). As impressoras produziram resultados de qualidade similares, embora a Moonray com a resina da Anycubic tenha mostrado perda de acurácia e a Anycubic tenha problema de consistência no plano vertical. Dentre elas, a impressão em PolyJet foi considerada o método mais rápido, porém com o custo muito elevado. A impressão em FFF apresenta um custo baixo da impressora e dos insumos, no entanto com o tempo de impressão consideravelmente mais elevado. Em ambas as impressoras DLP houve um equilíbrio, resultando em um bom custo-benefício(AU)

When choosing a 3D printer for dental models, cost-benefit should be evaluated. Printed models should be accurate, precise and time efficient, as well as financially accessible. The aim of this study is to compare the accuracy, precision, cost and time required for preparation and printing using different technologies: two DLP (Digital Light Processing) printers, and one FFF (Fused Filament Fabrication) compared to the gold standard (PolyJet). For this study, it was selected 10 intraoral scans of 5 patients. All 10 models were printed as follows: (1) DLP printer Moonray (MR), (2) DLP printer Anycubic (AC) (3) DLP printer Moonray with Anycubic resin (MRA), (4) filament printer UpMini 2 (FFF) and (5) PolyJet printer Objet eden500 (PJ). One of the virtual models was additionally printed four consecutive times on each printer to allow consistency assessment. The original .STL file of each model was superimposed by scanning its respective printed model, generating color maps that allowed the RMS (root mean square) calculation for the comparison of both models. In addition, linear measurements were performed using a digital caliper on 8 different variables: inter-canine distance (ICD), inter-molar distance (IMD), bilateral anteroposterior plane (APP-R and APP-L), bilateral vertical plane (VP-R and VP-L) and bilateral mixed plan (MP-R and MP-L). The Shapiro-Wilk test showed that the data was not normally distributed. Friedman's test with Bonferroni's post hoc test was used to verify if there were differences between the evaluated variables. A difference above 0.4 mm was considered clinically significant for linear measurements. Clinically and statistically significant differences (p <0.05) were observed for the following comparisons: VP-R and VP-L between MR and MRA (p = 0.00), VP-R between FFF and MR (p = 0.01), VP-L between FFF and MR (p = 0.00). For RMS, there were statistically significant differences between: AC and MR (p = 0.00); AC and MRA (p = 0.00); FFF and MR (p = 0.01) and PJ and MR (p = 0.00). For the differences in RMS, no value was above the clinical significancy threshold (0.25mm). When the consistency of the models by the linear measurements was evaluated, a statistically significant difference was observed only in the VP-R variable between FFF and AC (p = 0.00). The same difference was seen for the RMS values in: AC and MR (p = 0.02) and AC and MRA (p = 0.04). The printers produced similar quality results, although Moonray with Anycubic resin showed loss of accuracy and Anycubic has a consistency problem in vertical plane. Among them, PolyJet printing was considered the fastest one, but with the highest cost. FFF printing has a low printer and filament cost, but with considerably longer printing times. In both DLP printers there was a balance, resulting in a good cost-benefit(AU)

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)

Customizable template technique to harvest iliac crest bone graft for reconstructions of mandibular defects. / Técnica de template customizável para remoção de enxerto ósseo de crista ilíaca para reconstruções de defeitos mandibulares.

Bone graft harvesting from the anterior iliac crest is a good option for reconstructing mandibular defects after trauma or other diseases. In order to achieve optimal clinical results in reconstructive surgeries with bone grafts, accurate preoperative planning and prestigious surgical technique are paramount. Therefore, this paper describes the use of a customizable template that is indicated for obtaining free iliac bone block for immediate or late mandibular reconstructions following marginal or segmental defects. The template is based on a piece of malleable metal obtained from an aluminum beverage can. It is used transoperatively to demarcate the bone graft donor site, being especially useful because of the limited access to the inner table of the anterior ilium. The described customizable template has been shown as a useful tool to easily determine the size of the bone block to be harvested from the iliac region, improving surgical time and preventing removal of insufficient bone graft.

A remoção de enxerto da crista ilíaca anterior é uma boa opção para a reconstrução de defeitos mandibulares após ressecções por trauma ou outras doenças. Para obtenção de resultados clínicos de excelência em cirurgias reconstrutivas com enxertos ósseos, um planejamento pré-operatório preciso e uma refinada técnica cirúrgica são essenciais. Portanto, este artigo descreve o uso de um template customizável, que é indicado para obter bloco de osso ilíaco livre para reconstruções mandibulares imediatas ou tardias após defeitos marginais ou segmentares. O template é baseado em um fragmento de metal maleável obtido de uma lata de bebida de alumínio. Ele é utilizado no transoperatório para demarcar o sítio doador do enxerto ósseo e é especialmente útil devido ao acesso limitado à cortical interna da crista ilíaca. O template customizável tem se mostrado uma ferramenta de fácil aplicação para determinar o tamanho do bloco de enxerto a ser coletado da região ilíaca, otimizando o tempo cirúrgico e evitando a remoção insuficiente de enxerto ósseo.

Técnica de template customizável para remoção de enxerto ósseo de crista ilíaca para reconstruções de defeitos mandibulares / Customizable template technique to harvest iliac crest bone graft for reconstructions of mandibular defects

RESUMO A remoção de enxerto da crista ilíaca anterior é uma boa opção para a reconstrução de defeitos mandibulares após ressecções por trauma ou outras doenças. Para obtenção de resultados clínicos de excelência em cirurgias reconstrutivas com enxertos ósseos, um planejamento pré-operatório preciso e uma refinada técnica cirúrgica são essenciais. Portanto, este artigo descreve o uso de um template customizável, que é indicado para obter bloco de osso ilíaco livre para reconstruções mandibulares imediatas ou tardias após defeitos marginais ou segmentares. O template é baseado em um fragmento de metal maleável obtido de uma lata de bebida de alumínio. Ele é utilizado no transoperatório para demarcar o sítio doador do enxerto ósseo e é especialmente útil devido ao acesso limitado à cortical interna da crista ilíaca. O template customizável tem se mostrado uma ferramenta de fácil aplicação para determinar o tamanho do bloco de enxerto a ser coletado da região ilíaca, otimizando o tempo cirúrgico e evitando a remoção insuficiente de enxerto ósseo.

ABSTRACT Bone graft harvesting from the anterior iliac crest is a good option for reconstructing mandibular defects after trauma or other diseases. In order to achieve optimal clinical results in reconstructive surgeries with bone grafts, accurate preoperative planning and prestigious surgical technique are paramount. Therefore, this paper describes the use of a customizable template that is indicated for obtaining free iliac bone block for immediate or late mandibular reconstructions following marginal or segmental defects. The template is based on a piece of malleable metal obtained from an aluminum beverage can. It is used transoperatively to demarcate the bone graft donor site, being especially useful because of the limited access to the inner table of the anterior ilium. The described customizable template has been shown as a useful tool to easily determine the size of the bone block to be harvested from the iliac region, improving surgical time and preventing removal of insufficient bone graft.

Accuracy of stereolithographically printed digital models compared to plaster models.

OBJECTIVE: This study compared the accuracy of plaster models from alginate impressions and printed models from intraoral scanning. MATERIALS AND METHODS: A total of 28 volunteers were selected and alginate impressions and intraoral scans were used to make plaster models and digital models of their dentition, respectively. The digital models were printed using a stereolithographic (SLA) 3D printer with a horseshoe-shaped design. Two calibrated examiners measured distances on the plaster and printed models with a digital caliper. The paired t test was used to determine intraobserver error and compare the measurements. The Pearson correlation coefficient was used to evaluate the reliability of measurements for each model type. RESULTS: The measurements on plaster models and printed models show some significant differences in tooth dimensions and interarch parameters, but these differences were not clinically relevant, except for the transversal measurements. The upper and lower intermolar distances on the printed models were statistically significant and clinically relevant smaller. CONCLUSIONS: Printed digital models with the SLA 3D printer studied, with a horseshoe-shaped base made from intraoral scans cannot replace conventional plaster models from alginate impressions in orthodontics for diagnosis and treatment planning because of their clinically relevant transversal contraction.

Maxillary Reconstruction Using rhBMP-2 and Titanium Mesh: Technical Note About the Use of Stereolithographic Model / Reconstrucción Maxilar Utilizando rhBMP-2 y Malla de Titanio: Nota Técnica sobre el Uso de Modelo Estereolitográfico

Maxillary reconstruction is a common procedure in maxillofacial surgery; for this purpose is used autogenous bone, alloplastic bone or another one with different results. In all of them, traditionally the use of computed tomography is used to make the surgical plan, however, 3D models are not used frequently. This report show a new application of the stereolithography to anticipate the surgical treatment of maxillary reconstruction, using a titanium mesh and rhBMP-2 to obtain a predictable surgical result with diminished surgical time.

La reconstrucción maxilar es un procedimiento común en cirugía maxilofacial; para este propósito es utilizado hueso autógeno, hueso aloplástico u otro tipo de hueso con diferentes resultados. En todos ellos, tradicionalmente el uso de tomografía computadorizada se emplea para elaborar el plan quirúrgico, sin embargo, los modelos 3D no son utilizados con frecuencia. Este reporte presenta una nueva aplicación de la estereolitografia para anticipar el tratamiento quirúrgico de la reconstrucción maxilar, usando una malla de titanio y rhBMP-2 para obtener un resultado quirúrgico predecible con disminución del tiempo quirúrgico.