3D Foot Anthropometric Measurements Under Two Weight- Bearing Conditions for Ergonomic Design of Foot-Related Products / Mediciones Antropométricas del Pie en 3D Bajo Dos Condiciones de Soporte de Peso para el Diseño Ergonómico de Productos Relacionados con los Pies

SUMMARY: This study collected 3D models of the left and right feet from 317 Chinese youth (155 females and 162 males) under half weight-bearing and no weight-bearing conditions. Thirteen dimensions and one angle were taken for each sample. By measuring 13 foot dimensions and 1 angle, this study comprehensively investigated the differences in foot shape between genders and the bilateral differences, as well as the foot shape differences under different conditions. The results showed that regardless of the condition, male foot dimensions were significantly larger than those of females. However, female foot shape was not simply a scaled-down version of male foot shape. On the contrary, the average angle of female feet was greater than that of males under both conditions, indicating a higher prevalence of hallux valgus in females. Both males and females exhibited significant correlation in foot dimensions between the left and right feet, with minimal differences. Under the half weight-bearing condition, the average foot length, width, and circumference were significantly larger than the corresponding measurements under the no weight-bearing condition, while the average height and angle were significantly smaller. Therefore, when designing footwear and foot-related medical rehabilitation aids, it is important to consider foot shape and dimensions under different conditions as a reference. The results of this study provide manufacturers of foot- related products with more detailed data support and are of significant value to the field of medical foot morphology research.

Este estudio recolectó modelos 3D de los pies izquierdo y derecho de 317 jóvenes chinos (155 mujeres y 162 hombres) en condiciones de carga media de peso y sin carga de peso. Para cada muestra se tomaron trece dimensiones y un ángulo. Al medir 13 dimensiones del pie y 1 ángulo, se investigó exhaustivamente las diferencias en la forma del pie entre ambos sexos y sus diferencias bilaterales, así como las diferencias en la forma del pie en diferentes condiciones. Los resultados mostraron que, independientemente de la condición, las dimensiones del pie de los hombres, estos eran significativamente más grandes que los de las mujeres. Sin embargo, la forma del pie femenino no era simplemente una versión reducida de la forma del pie masculino. Por el contrario, el ángulo promedio de los pies de las mujeres fue mayor que el de los hombres en ambas condiciones, lo que indica una mayor prevalencia de hallux valgus en las mujeres. Tanto hombres como mujeres exhibieron una correlación significativa en las dimensiones del pie, entre el pie izquierdo y el derecho, con diferencias mínimas. Bajo la condición de medio soporte de peso, la longitud, el ancho y la circunferencia promedio del pie fueron significativamente mayores que las medidas correspondientes bajo la condición sin soporte de peso, mientras que la altura y el ángulo promedio fueron significativamente más pequeños. Por lo tanto, al diseñar calzado y dispositivos médicos de rehabilitación relacionados con los pies, es importante tener en consideración la forma y las dimensiones del pie en diferentes condiciones como referencia. Los resultados de este estudio, brindan a los fabricantes de productos relacionados con los pies un soporte de datos más detallado y son de gran valor para el campo de la investigación médica de la morfología del pie.

Nuevos Recursos Digitales y 3D en la Enseñanza de Anatomía. Experiencia Internacional Reportada en el "Sectra Users Meeting 2019", Karolinska Institutet, Suecia, antes de la Pandemia de COVID-19 / New Digital and 3D Resources in the Teaching of Anatomy. International Experience Reported in the "Sectra Users Meeting 2019", Karolinska Institutet, Sweden, Before the Pandemic COVID-19

El uso de nuevos recursos tecnológicos en la enseñanza de anatomía ha impulsado la necesidad de adaptar el modelo educativo haciéndolo más centrado en el estudiante, dinámico y participativo mediante herramientas digitales y 3D; orientando los conocimientos hacia su aplicación clínica, pero bajo un ajuste curricular que tiende a cursar menos horas presenciales en aula o laboratorio. Este trabajo describe la experiencia local de una nueva Escuela de Medicina en Chile, reportada el año 2018, además y otros trabajos de centros formadores presentados en el "SECTRA Users Meeting 2019 Estocolmo", Karolinska Institutet, Suecia. Este trabajo describe los reportes orales sobre la aplicación de nuevos recursos digitales como; la mesa de disección digital táctil SECTRA® y modelos anatómicos cadavéricos impresos en 3D Erler-Zimmer®, bases de datos sobre anatomía digital, además, su impacto en el desempeño académico, reportado por usuarios de diferentes países, tales como: Australia, Canadá, Chile, China, Colombia, Estados Unidos de Norteamérica (EUA) y Suecia. Los datos fueron recopilados y analizados a partir de la información reportada en las presentaciones orales y resúmenes entregados por los expositores. La gran mayoría de los países expositores declararon el uso combinado de recursos digitales y 3D sumados a los tradicionales para la enseñanza de anatomía. Sólo el representante de EUA declaró usar exclusivamente recursos digitales (en laboratorio y en línea), experiencia correspondiente a una joven e innovadora escuela de medicina. La mayoría de los centros docentes declaró utilizar la mesa de disección digital en una amplia proporción de sus contenidos curriculares, en asociación a plataformas tipo RIS/PACS como IDS7 portal de SECTRA o las utilizadas por el centro formador. El uso de nuevas tecnologías digitales y 3D ha ganado un importante espacio en el currículum de la enseñanza de anatomía, complementando el uso de los recursos tradicionales.

SUMMARY: The use of new technological resources in the teaching of anatomy has promoted the need to adapt the educational model, making it more student-centered, dynamic, and participatory through digital and 3D tools, directing the knowledge towards its clinical application, but under a curricular adjustment that tends to take fewer contact hours in the classroom or laboratory. This work describes the local experience of a new School of Medicine in Chile, reported in 2018, and other work from training centers presented at the "SECTRA Users Meeting 2019 Stockholm", Karolinska Institutet, Sweden. This work describes the oral reports on the application of new digital resources such as; the SECTRA® digital tactile dissection table and Erler- Zimmer® 3D printed cadaveric anatomical models, databases on digital anatomy, in addition, its impact on academic performance, reported by users from different countries, such as Australia, Canada, Chile, China, Colombia, United States of America (USA) and Sweden. The data was collected and analyzed from the information reported in the oral presentations and summaries delivered by the speakers.The vast majority of the exhibiting countries declared the combined use of digital and 3D resources added to the traditional ones for teaching anatomy. Only the representative from the USA stated that they exclusively used digital resources (in the laboratory and online), an experience corresponding to a young and innovative medical school. Most of the educational centers stated that they used the digital dissection table in a large proportion of their curricular contents, in association with RIS/PACS-type platforms such as the IDS7 SECTRA portal or those used by the training center. The use of new digital and 3D technologies has gained an important space in the anatomy teaching curriculum, complementing the use of traditional resources.

Sex estimation based on foramen magnum: a three-dimensional geometric morphometrics approach / Estimación del sexo basado en el foramen magno: un enfoque de morfometría geométrica tridimensional

SUMMARY: The foramen magnum is an important topographic opening which connects cranial cavity and spinal canal. The analysis of the bone material established that there are differences in the shape of the foramen magnum between individuals. The aim of this study was to determine sex based on shape and size of foramen magnum using geometric morphometrics method. A study was performed on three-dimensional models (3D models) of 214 human skulls of known sex and known age (141 male skulls and 73 female skulls). The skulls are located at the museum of Medical Faculty, University of Sarajevo. Skulls belong to Bosnian population from the mid-twentieth century. All examined skulls were scanned with a laser scanner to obtain their 3D models. On 3D models of the examined skulls, four landmarks were marked on foramen magnum. Analysis of sex determination was performed using the MorphoJ program. Results of this study showed that there are sex differences in the shape and size of the foramen magnum. Sex determination based on the shape and size of the foramen magnum was showed 65.25 % accuracy for male and 63.01 % accuracy for female using geometric morphometrics method. Examination of the effect of size of foramen magnum on sexual dimorphism of shape of foramen magnum showed a statistically significant effect. Sex determination based just on the shape of foramen magnum using geometric morphometrics method was possible with 62.41 % accuracy for male and 58.90 % accuracy for female on examined sample. Sex differences on shape and size of foramen magnum were found using geometric morphometrics method on three-dimensional models of the examined skulls. The percentage of accuracy was higher for male based on the shape and size of the foramen magnum than for female.

El foramen magno es una importante abertura topográfica que conecta la cavidad craneal y el canal espinal. El análisis del material óseo estableció que existen diferencias en la forma del foramen magno entre individuos. El objetivo de este estudio fue determinar el sexo en función de la forma y el tamaño del foramen magno utilizando morfometría geométrica. El estudio se realizó en modelos tridimensionales (modelos 3D) de 214 cráneos humanos de sexo y edad conocidos (141 cráneos masculinos y 73 cráneos femeninos). Los cráneos se encuentran en el museo de la Facultad de Medicina de la Universidad de Sarajevo. Los cráneos pertenecen a población bosnia de mediados del siglo XX. Todos los cráneos examinados fueron escaneados con un escáner láser para obtener sus modelos 3D. En los modelos 3D de los cráneos examinados, se marcaron cuatro puntos de referencia en el foramen magno. El análisis de determinación de sexo se realizó utilizando el programa MorphoJ. Los resultados de este estudio mostraron que existen diferencias de sexo en la forma y el tamaño del foramen magno. La determinación del sexo basada en la forma y el tamaño del foramen magno mostró una precisión del 65,25 % para los hombres y del 63,01 % para las mujeres utilizando morfometría geométrica. El examen del efecto del tamaño del foramen magno sobre el dimorfismo sexual de la forma del foramen magno mostró un efecto estadísticamente significativo. La determinación del sexo basada solo en la forma del foramen magno utilizando morfometría geométrica fue posible con una precisión del 62,41 % para los hombres y del 58,90 % para las mujeres en la muestra examinada. Se encontraron diferencias de sexo en la forma y el tamaño del foramen magno utilizando morfometría geométrica en modelos tridimensionales de los cráneos examinados. El porcentaje de precisión fue mayor para los hombres en función de la forma y el tamaño del foramen magno que para las mujeres.

Evaluation of angles of the tracheobronchial tree with the 3-dimensional reconstruction method: a morphometric and radiologic study / Evaluación de los ángulos del árbol traqueobronquial con el método de reconstrucción tridimensional: un estudio morfométrico y radiológico

SUMMARY: The objective of the current research is to assess the branching angles of the tracheobronchial tree and the correlation between these angles and the lung volume using the 3-dimensional reconstruction method. Thorax CT (computed tomography) images of 150 individuals, who were over 18 years of age and did not have any pathology on CT, were obtained retrospectively. A 3-dimensional reconstruction of the trachea, bronchi, and lungs was carried out. External and internal angles between the trachea and main bronchi, between the main bronchi and lobar bronchi, and between the lobar bronchi were measured. The volume measurement of the right and left lungs was performed. The individuals included in the study were grouped by sex and age (20-40 years, 41-61 years, and 62-87 years). The left subcarinal angle (LSA), total subcarinal angle (TSA), and left interbronchial angle (LIA) were found to be greater in the 62-87 age group. Both the external angle (LULB-LMBE) and the internal angle (LULB- LMBI) between the left upper lobar bronchus and the left main bronchus were observed to be greater in males. In males, a statistically significant negative moderate correlation was identified between the right lung volume and the right subcarinal angle (RSA). In females, a statistically significant positive moderate correlation was revealed between the external (RULB-IBE) and internal angles (RULB-IBI) between the right upper lobar bronchus and the intermediate bronchus, and the right lung volume. In the literature review we performed, we did not find any studies investigating the correlation between the branching angles of the tracheobronchial tree and the lung volume using the 3-dimensional reconstruction method. Therefore, we are of the opinion that our study will contribute to the literature.

El objetivo de la investigación fue evaluar los ángulos de ramificación del árbol traqueobronquial y la correlación entre estos ángulos y el volumen pulmonar utilizando el método de reconstrucción tridimensional. Se obtuvieron retrospectivamente imágenes de tomografía computarizada de tórax de 150 individuos mayores de 18 años sin patología. Se realizó una reconstrucción tridimensional de la tráquea, los bronquios y los pulmones. Se midieron los ángulos externo e interno entre la tráquea y los bronquios principales, entre los bronquios principales y los bronquios lobares, y entre los bronquios lobares. Se realizó la medición del volumen de los pulmones derecho e izquierdo. Los individuos incluidos en el estudio fueron agrupados por sexo y edad (20-40 años, 41-61 años y 62-87 años). Se encontró que el ángulo subcarinal izquierdo, el ángulo subcarinal total y el ángulo interbronquial izquierdo eran mayores en el grupo de edad de 62 a 87 años. Tanto el ángulo externo (LULB-LMBE) como el ángulo interno (LULB-LMBI) entre el bronquio lobular superior izquierdo y el bronquio principal izquierdo era mayor en los hombres. En los hombres, se identificó una correlación moderada negativa estadísticamente significativa entre el volumen pulmonar derecho y el ángulo subcarinal derecho. En mujeres, se reveló una correlación positiva moderada estadísticamente significativa entre los ángulos externos (RULB-IBE) e internos (RULB-IBI) entre el bronquio lobar superior derecho y el bronquio intermedio, y el volumen pulmonar derecho. En la revisión bibliográfica que realizamos, no encontramos ningún estudio que analizara la correlación entre los ángulos de ramificación del árbol traqueobronquial y el volumen pulmonar utilizando el método de reconstrucción tridimensional. Por lo tanto, consideramos que nuestro estudio contribuirá a la literatura especializada del tema.

Morphometric examination of the trachea and bronchi in follow-up computed tomography scans of COVID-19 patients / Examen morfométrico de la tráquea y los bronquios en tomografías computarizadas de seguimiento de pacientes con COVID-19

SUMMARY: The purpose of this study is to evaluate changes in the trachea and bronchi using 3-dimensional reconstruction images obtained from the initial and follow-up computed tomography (CT) scans of COVID-19 patients. A hundred COVID-19 patients over the age of 18 were included in our study. CT images were transferred to Mimics software, and a 3-dimensional reconstruction of the trachea and bronchi was performed. The initial and follow-up CT images of COVID-19 patients were graded as none (grade 0), mild (grade 1), moderate (grade 2), and severe (grade 3) according to the total lung severity score. The patients were divided into progression and regression groups according to the grade increase/decrease between the initial and follow-up CTs. Moreover, the patients were divided into groups as 0-2 weeks, 2-4 weeks, 4-12 weeks, and over 12 weeks according to the duration between the initial and follow-up CTs. The mean cross-sectional area, circumference, and diameter measurements of the right upper lobar bronchus, intermediate bronchus, middle lobar bronchus, and left lower lobar bronchus decreased in the follow-up CTs of the progression group. This decrease was not found to be statistically significant. In the follow-up CTs of the regression group, the left upper lobar bronchus and left lower lobar bronchus measurements increased but not statistically significant. Upon comparing the onset of the disease and the follow-up period, statistically significant changes did not occur in the trachea, main bronchus, and lobar bronchus of COVID-19 patients.

El propósito de este estudio fue evaluar los cambios en la tráquea y los bronquios utilizando imágenes de reconstrucción tridimensionales obtenidas de las tomografías computarizadas (TC) iniciales y de seguimiento de pacientes con COVID-19. En nuestro estudio se incluyeron 100 pacientes con COVID-19 mayores de 18 años. Las imágenes de TC se transfirieron al software Mimics y se realizó una reconstrucción tridimensional de la tráquea y los bronquios. Las imágenes de TC iniciales y de seguimiento de los pacientes con COVID-19 se calificaron como ninguna (grado 0), leve (grado 1), moderada (grado 2) y grave (grado 3) según la puntuación total de gravedad pulmonar. Los pacientes se dividieron en grupos de progresión y regresión según el aumento/disminución del grado entre las TC iniciales y de seguimiento. Además, los pacientes se dividieron en grupos de 0 a 2 semanas, de 2 a 4 semanas, de 4 a 12 semanas y de más de 12 semanas según la duración entre la TC inicial y la de seguimiento. Las mediciones medias del área transversal, la circunferencia y el diámetro del bronquio lobar superior derecho, el bronquio intermedio, el bronquio lobar medio y el bronquio lobar inferior izquierdo disminuyeron en las TC de seguimiento del grupo de progresión. No se encontró que esta disminución fuera estadísticamente significativa. En las TC de seguimiento del grupo de regresión, las mediciones del bronquio lobar superior izquierdo y del bronquio lobar inferior izquierdo aumentaron pero no fueron estadísticamente significativas. Al comparar el inicio de la enfermedad y el período de seguimiento, no ocurrieron cambios estadísticamente significativos en la tráquea, el bronquio principal y el bronquio lobar de los pacientes con COVID-19.

Application of 3D Printing Technology in the Treatment of Hoffa's Fracture Nonunion / Aplicação da tecnologia de impressão 3D no tratamento da pseudartrose da fratura de Hoffa

Abstract Objective To evaluate a proposed three-dimensional (3D) printing process of a biomodel developed with the aid of fused deposition modeling (FDM) technology based on computed tomography (CT) scans of an individual with nonunion of a coronal femoral condyle fracture (Hoffa's fracture). Materials and Methods Thus, we used CT scans, which enable the evaluation of the 3D volumetric reconstruction of the anatomical model, as well as of the architecture and bone geometry of sites with complex anatomy, such as the joints. In addition, it enables the development of the virtual surgical planning (VSP) in a computer-aided design (CAD) software. This technology makes it possible to print full-scale anatomical models that can be used in surgical simulations for training and in the choice of the best placement of the implant according to the VSP. In the radiographic evaluation of the osteosynthesis of the Hoffa's fracture nonunion, we assessed the position of the implant in the 3D-printed anatomical model and in the patient's knee. Results The 3D-printed anatomical model showed geometric and morphological characteristics similar to those of the actual bone. The position of the implants in relation to the nonunion line and anatomical landmarks showed great accuracy in the comparison of the patient's knee with the 3D-printed anatomical model. Conclusion The use of the virtual anatomical model and the 3D-printed anatomical model with the additive manufacturing (AM) technology proved to be effective and useful in planning and performing the surgical treatment of Hoffa's fracture nonunion. Thus, it showed great accuracy in the reproducibility of the virtual surgical planning and the 3D-printed anatomical model.

Resumo Objetivo Avaliar uma proposta de processo de impressão tridimensional (3D) de um biomodelo preparado com o auxílio da tecnologia de modelagem por deposição de material fundido (fused deposition modeling, FDM, em inglês) a partir de imagens de tomografia computadorizada (TC) de um indivíduo com pseudartrose de fratura coronal do côndilo femoral (fratura de Hoffa). Materiais e Métodos Para tanto, utilizamos imagens de TC, que permitem estudar a reconstrução volumétrica 3D do modelo anatômico, além da arquitetura e geometria óssea de sítios de anatomia complexa, como as articulações. Também permite o planejamento cirúrgico virtual (PCV) em um programa de desenho assistido por computador (computer-aided design, CAD, em inglês). Essa tecnologia possibilita a impressão de modelos anatômicos em escala real que podem ser utilizados em simulações cirúrgicas para o treinamento e a escolha do melhor posicionamento do implante de acordo com o PCV. Na avaliação radiográfica da osteossíntese da pseudartrose de Hoffa, verificou-se a posição do implante no modelo anatômico impresso em 3D e no joelho do paciente. Resultados O modelo anatômico impresso em 3D apresentou características geométricas e morfológicas semelhantes às do osso real. O posicionamento dos implantes em relação à linha de pseudartrose e pontos anatômicos foram bastante precisos na comparação do joelho do paciente com o modelo anatômico impresso em 3D. Conclusão A utilização do modelo anatômico virtual e do modelo anatômico impresso em 3D com a tecnologia de manufatura aditiva (MA) foi eficaz e auxiliou o planejamento e a realização do tratamento cirúrgico da pseudartrose da fratura de Hoffa. Desta forma, foi bastante preciso na reprodutibilidade do planejamento cirúrgico tanto virtual quanto no modelo anatômico impresso em 3D.

Prototyping and 3D printing of computed tomography images with an emphasis on soft tissues, especially muscles, for teaching human anatomy / Prototipado e impresión 3D de imágenes de tomografía computarizada con énfasis en los tejidos blandos, especialmente músculos, para la enseñanza de la anatomía humana

SUMMARY: The study on cadavers, although considered fundamental in the teaching of human anatomy, is limited in several universities, mainly due to the acquisition and manipulation of cadaveric material. Throughout history, several artificial anatomical models have been used to complement the real anatomical pieces. The present study offers a new alternative: the making of three-dimensional models from Computed Tomography (3D-CT) patient image acquisition. CT images from the USP University Hospital database were used. Patients underwent examinations for reasons other than the present study and were anonymized to maintain confidentiality. The CT slices obtained in thin cross-sections (approximately 1.0 mm thick) were converted into three-dimensional images by a technique named Volume Rendering for visualization of soft tissue and bone. The reconstructions were then converted to an STL (Standard Triangle Language) model and printed through two printers (LONGER LK4 Pro® and Sethi S3®), using PLA and ABS filaments. The 3D impressions of the thigh and leg muscles obtained better visual quality, being able to readily identify the local musculature. The images of the face, heart, and head bones, although easily identifiable, although seemed to present lower quality aesthetic results. This pilot study may be one of the first to perform 3D impressions of images from CT to visualize the musculature in Brazil and may become an additional tool for teaching.

El estudio en cadáveres, a pesar de considerarse un aspecto fundamental en la enseñanza de la anatomía humana, se encuentra limitado en varias universidades, principalmente por la adquisición y manipulación de material cadavérico. A lo largo de la historia se han utilizado varios modelos anatómicos artificiales para complementar las piezas anatómicas reales. El presente estudio ofrece una nueva alternativa: la elaboración de modelos tridimensionales a partir de la adquisición de imágenes de pacientes por Tomografía Computarizada (3D-CT). Se utilizaron imágenes de TC de la base de datos del Hospital Universitario de la USP. Los pacientes se sometieron a exámenes por razones distintas al presente estudio y fueron anonimizados para mantener la confidencialidad. Los cortes de TC obtenidos en secciones transversales delgadas (aproximadamente 1,0 mm de grosor) se convirtieron en imágenes tridimensionales mediante una técnica denominada Volume Rendering para la visualización de tejido blando y hueso. Luego, las reconstrucciones se convirtieron a un modelo STL (Standard Triangle Language) y se imprimieron a través de dos impresoras (LONGER LK4 Pro® y Sethi S3®), utilizando filamentos PLA y ABS. Se obtuvo una mejor calidad visual de las impresiones 3D de los músculos del muslo y la pierna, pudiendo identificar fácilmente la musculatura local. Las imágenes de la cara, el corazón y los huesos de la cabeza, aunque fácilmente identificables, parecían presentar resultados estéticos de menor calidad. Este estudio piloto puede ser uno de los primeros en realizar impresiones 3D de imágenes de TC para visualizar la musculatura y podría ser en una herramienta adicional para la enseñanza.

Embedded 3D printing of porous silicon orbital implants and its surface modification / 南方医科大学学报

OBJECTIVE@#To prepare customized porous silicone orbital implants using embedded 3D printing and assess the effect of surface modification on the properties of the implants.@*METHODS@#The transparency, fluidity and rheological properties of the supporting media were tested to determine the optimal printing parameters of silicone. The morphological changes of silicone after modification were analyzed by scanning electron microscopy, and the hydrophilicity and hydrophobicity of silicone surface were evaluated by measuring the water contact angle. The compression modulus of porous silicone was measured using compression test. Porcine aortic endothelial cells (PAOECs) were co-cultured with porous silicone scaffolds for 1, 3 and 5 days to test the biocompatibility of silicone. The local inflammatory response to subcutaneous porous silicone implants was evaluated in rats.@*RESULTS@#The optimal printing parameters of silicone orbital implants were determined as the following: supporting medium 4% (mass ratio), printing pressure 1.0 bar and printing speed 6 mm/s. Scanning electron microscopy showed that the silicone surface was successfully modified with polydopamine and collagen, which significantly improved hydrophilicity of the silicone surface (P < 0.05) without causing significant changes in the compression modulus (P > 0.05). The modified porous silicone scaffold had no obvious cytotoxicity and obviously promoted adhesion and proliferation of PAOECs (P < 0.05). In rats bearing the subcutaneous implants, no obvious inflammation was observed in the local tissue.@*CONCLUSION@#Poprous silicone orbital implants with uniform pores can be prepared using embedded 3D printing technology, and surface modification obviously improves hydrophilicity and biocompatibility of the silicone implants for potential clinical application.

3D-printed vertebral body in anterior spinal reconstruction after total spondylectomy for patients with cervical chordoma / 北京大学学报(医学版)

OBJECTIVE@#To investigate whether 3D-printed artificial vertebral body can reduce prosthesis subsidence rate for patients with cervical chordomas, through comparing the rates of prosthesis subsidence between 3D printing artificial vertebral body and titanium mesh for anterior spinal reconstruction after total spondylectomy.@*METHODS@#This was a retrospective analysis of patients who underwent surgical treatment for cervical chordoma at our hospital from March 2005 to September 2019. There were nine patients in the group of 3D artificial vertebral body (3D group), and 15 patients in the group of titanium mesh cage (Mesh group). The patients' characteristics and treatment data were extracted from the medical records, including age, gender, CT hounsfield unit of cervical vertebra and surgical information, such as the surgical segments, time and blood loss of surgery, frequency and degree of prosthesis subsidence after surgery. Radiographic observations of prosthesis subsidence during the follow-up, including X-rays, CT, and magnetic resonance imaging were also collected. SPSS 22.0 was used to analysis the data.@*RESULTS@#There was no significant difference between the two groups in gender, age, CT hounsfield unit, surgical segments, time of surgery, blood loss of posterior surgery and total blood loss. Blood loss of anterior surgery was 700 (300, 825) mL in 3D group and 1 500 (750, 2 800) mL in Mesh group (P < 0.05). The prosthesis subsidence during the follow-up, 3 months after surgery, there was significant difference between the two groups in mild prosthesis subsidence (P < 0.05). The vertebral height of the 3D group decreased less than 1 mm in eight cases (no prosthesis subsidence) and more than 1 mm in one case (mild prosthesis subsidence). The vertebral height of the Mesh group decreased less than 1 mm in five cases (no prosthesis subsidence), and more than 1 mm in eight cases (mild prosthesis subsidence). Two patients did not have X-rays in 3 months after surgery. There was a statistically significant difference between the two groups in the prosthesis subsidence rate at the end of 12 months (P < 0.01). The vertebral height of eight cases in the 3D group decreased less than 1 mm (no prosthesis subsidence) and one case more than 3 mm (severe prosthesis subsidence). Four of the 15 cases in the Mesh group decreased less than 1 mm (no prosthesis subsidence), two cases more than 1 mm (mild prosthesis subsidence), and nine cases more than 3 mm (severe prosthesis subsidence). There was a statistically significant difference between the two groups in the prosthesis subsidence rate at the end of 24 months (P < 0.01). The vertebral height of seven cases in the 3D group decreased less than 1 mm (no prosthesis subsidence), one case more than 3 mm (severe prosthesis subsidence), and one case died with tumor. One case in the Mesh group decreased less than 1 mm (no prosthesis subsidence), one case more than 1 mm (mild prosthesis subsidence), 11 case more than 3 mm (severe prosthesis subsidence), one case died with tumor and one lost the follow-up. Moreover, at the end of 12 months and 24 months, there was significant difference between the two groups in severe prosthesis subsidence rate (P < 0.01).@*CONCLUSION@#3D-printed artificial vertebral body for anterior spinal reconstruction after total spondylectomy for patients with cervical chordoma can provide reliable spinal stability, and reduce the incidence of prosthesis subsidence after 2-year follow-up.

Application of 3D printing percutaneous guide plate in closed reduction and cannulated screw internal fixation of femoral neck fracture / 中国骨伤

OBJECTIVE@#To investigate the application of 3D printing percutaneous surgical guide plate in closed reduction and cannulated screw internal fixation of femoral neck fracture.@*METHODS@#The clinical data of 12 patients with femoral neck fracture from March 2019 to March 2022 were retrospectively analyzed. Patients were divided into observation group and control group according to different operation plans, with 6 cases in each group. The observation group received percutaneous operation guide plate assisted closed reduction and hollow screw internal fixation, while the control group received closed reduction and hollow compression screw internal fixation. The operation time, intraoperative blood loss, fluoroscopy times, and Kirschner needle puncture times were compared between two groups. The location of screws were recordedon postoperative X-ray films, follow-up time, time of complete fracture healing, Harris score of hip joint and the incidence of complications were recorded on postoperative X-ray films.@*RESULTS@#The operation time of observation group (32.17±6.18) min was shorter than that of control group (53.83±7.31) min (P<0.05). The amount of intraoperative bleeding in the observation group (18.33±2.94) ml was less than that in the control group (38.17±5.56) ml(P<0.05). The times of fluoroscopy in the observation group (7.50±1.05) were less than those in the control group (21.00±4.82) (P<0.05). The number of Kirschner needle punctures (8.00±0.63) in observation group was less than that in control group (32.67±3.08) (P<0.05). The follow-up time was(12.88±0.74) months in observation group and (12.83±0.72) months in control group, there was no significant difference between two groups (P>0.05). One year after operation, Harris score of hip joint in the observation group was(82.00±4.52) points, while that in the control group was(81.00±3.41) points, there was no significant difference between two groups(P>0.05). The time of complete fracture healing in the observation group was (7.50±1.05) months, while that in the control group was (7.67±1.21) months, there was no significant difference between two groups(P>0.05). The parallelism of the screws in the observation group was (0.50±0.11) ° and (0.76±0.15) °, which were lower than that in the control group (1.57±0.31) ° and (1.87±0.21) ° (P<0.05). The screw distribution area ratio (0.13±0.02) cm2 in the observation group was higher than that in the control group (0.08±0.01) cm2 (P<0.05). No complications such as necrosis of femoral head, nonunion of fracture, shortening of femoral neck and withdrawal of internal fixation occurred in both groups.@*CONCLUSION@#The application of 3D printing percutaneous surgical guide plate improves the accuracy and safety of closed reduction and cannulated screw internal fixation for femoral neck fracture. It has the advantages of minimally invasive, reducing radiation exposure, fast and accurate, shortening the operation time and reducing intraoperative bleeding.

Applications of digital medical techniques for dental dysplasia / 中华口腔医学杂志

Dental dysplasia are abnormalities in teeth structure, morphology, number and eruption caused by genetic and environmental factors during dental development. Digital medical techniques, as the current hot spot of medical research, bring great challenges and opportunities to modern stomatology. The applications of digital techniques, such as digital diagnosis method, digital virtual simulated design, three-dimensional printing, static and dynamic guidance and artificial intelligence, can provide a more accurate, efficient, automatic and intelligent modern concepts and patterns for epidemiology, diagnosis, multidisciplinary treatment and outcome assessment of dental developmental anomalies.

Effect analysis of myectomy guided by personalized three-dimensional reconstruction and printing in the treatment of obstructive hypertrophic cardiomyopathy / 中华外科杂志

Objective: To examine the clinical efficacy of myectomy guided by personalized three-dimensional reconstruction and printing for patients with obstructive hypertrophic cardiomyopathy. Methods: The clinical data of 28 patients with obstructive hypertrophic cardiomyopathy, who underwent septal myectomy guided by personalized three-dimensional reconstruction and printing in the Department of Cardiaovascular Surgery, Guangdong Provincial People's Hospital from May 2020 to December 2021, were retrospectively analyzed. There were 14 males and 14 females, aging (51.1±14.0) years (range: 18 to 72 years). Enhanced cardiac computed tomography images were imported into Mimics software for preoperative three-dimensional reconstruction. The direction of the short axial plane of each segment was marked perpendicularly to the interventricular septum on the long axial plane of the digital cardiac model, then the thickness was measured on each short axial plane. A figurative digital model was used to determine the extent of resection and to visualize mitral valve and papillary muscle abnormalities. Correlation between the length, width, thickness, and volume of the predicted resected myocardium and those of the surgically resected myocardium was assessed by Pearson correlation analysis or Spearman correlation analysis. The accuracy of detecting mitral valve and papillary muscle abnormalities of transthoracic echocardiography and three-dimensional reconstruction was also compared. Results: There was no death or serious complications like permanent pacemaker implantation, re-sternotomy for bleeding, low cardiac output syndrome, stroke, or multiple organ dysfunction syndromes in the whole group. Namely, the obstruction of the left ventricular outflow tract was effectively relieved. The systolic anterior motion of the anterior mitral valve leaflet was absent in all patients after myectomy. The length, width, and thickness of the predicted resected myocardium by three-dimensional reconstruction were significantly positively correlated with the length (R=0.65, 95%CI: 0.37 to 0.82, P<0.01), width (R=0.39, 95%CI: 0.02 to 0.67, P<0.01), and thickness (R=0.82, 95%CI: 0.65 to 0.92, P<0.01) of the surgically resected myocardium, while the relation of the volume of the predicted resected myocardium and the volume of the surgically resected myocardium was a strong positive correlation (R=0.88, 95%CI: 0.76 to 0.94, P<0.01). Importantly, the interventricular septal myocardial thickness measured by preoperative transthoracic echocardiography showed a moderate positive correlation with the volume of surgically resected myocardium (R=0.52, 95%CI: 0.19 to 0.75, P<0.01). During a follow-up of (14.4±6.8) months (range: 3 to 22 months), no death occurred, and 1 patient was readmitted for endocardial radiofrequency ablation due to atrial fibrillation. Conclusion: Personalized three-dimensional reconstruction and printing can not only visualize the intracardiac structure but also guide septal myectomy by predicting the thickness, volume, and extent of resected myocardium to achieve ideal resection.

Research status and prospect of tissue engineering technology in treatment of atrophic rhinitis / 中国修复重建外科杂志

OBJECTIVE@#To review the research progress of the feasibility of a new treatment method for atrophic rhinitis (ATR) based on tissue engineering technology (seed cells, scaffold materials, and growth factors), and provide new ideas for the treatment of ATR.@*METHODS@#The literature related to ATR was extensively reviewed. Focusing on the three aspects of seed cells, scaffold materials, and growth factors, the recent research progress of ATR treatment was reviewed, and the future directions of tissue engineering technology to treat ATR were proposed.@*RESULTS@#The pathogenesis and etiology of ATR are still unclear, and the effectiveness of the current treatments are still unsatisfactory. The construction of a cell-scaffold complex with sustained and controlled release of exogenous cytokines is expected to reverse the pathological changes of ATR, promoting the regeneration of normal nasal mucosa and reconstructing the atrophic turbinate. In recent years, the research progress of exosomes, three-dimensional printing, and organoids will promote the development of tissue engineering technology for ATR.@*CONCLUSION@#Tissue engineering technology can provide a new treatment method for ATR.

Resistência flexural de uma resina para impressão 3D comparada a resinas acrílicas convencionais empregadas para confecção de placas estabilizadoras de mordida / Flexural resistance of 3D printing resin compared to conventional acrylic resins employed to build occlusal bite splints

Introduction: with the technological advance in dentistry, light-polymerized three-dimensional (3D) printing resins had become an alternative for the manufacture of occlusal splint splints. Objective: the present study aimed to analyze the flexural strength of a resin for 3D printing compared to conventional acrylic resins (chemically activated and thermally activated), under the influence of thermocycling. Material and method: 60 specimens were made, which were distributed in six experimental groups (n = 10), according to the resin employed (chemically activated acrylic resin, thermally activated acrylic resin and 3D printing resin) and the treatment received (control and thermocycling). The specimens were submitted to flexural strength by the three-point flexural test. Result: data analysis showed that the material factor (<0.0001) and the thermocycling factor (p = 0.0096) influenced flexural strength, however, the interaction between the two factors did not (p = 0.9728). Conclusion: it was concluded that 3D printing resins presented the lowest flexural resistance to acrylic resins, especially when submitted to thermocycling.

Introdução: com o avanço tecnológico dentro da odontologia, as resinas fotopolimerizáveis para impressão tridimensional (3D) se tornaram uma alternativa para a fabricação de dispositivos interoclusais. Objetivo: o presente trabalho teve como objetivo analisar a resistência flexural de uma resina para impressão tridimensional comparada com resinas acrílicas convencionais (quimicamente ativada e termicamente ativada), sob a influência da termociclagem. Material e método: foram confeccionados 60 corpos de prova, que foram distribuídos aleatoriamente em seis grupos experimentais (n=10), de acordo com a resina utilizada (resina acrílica ativada quimicamente, resina acrílica ativada termicamente e resina para impressão 3D) e com o tratamento recebido (controle e termociclagem). Os corpos de prova foram submetidos ao ensaio de flexão de três pontos para determinação da resistência flexural. Resultado: a análise dos dados demonstrou que o fator material (<0.0001) e o fator termociclagem (p=0.0096) influenciaram a resistência flexural, entretanto, a interação entre os dois fatores não (p=0.9728). Conclusão: deste modo podemos concluir que a resina para impressão 3D apresentou desempenho inferior às resinas acrílicas, especialmente quando submetida a termociclagem.

Odontologia digital - abordagem histórica e conceitual: uma revisão de literatura / Digital dentistry - historical and conceptual approach: a literature review

Introdução: as inovações tecnológicas contribuem e representam um papel importante em diversos aspectos da vida cotidiana dos indivíduos em sociedade. Diferentes áreas do conhecimento trabalham com as ferramentas tecnológicas e digitais, dentre estas áreas, destaca-se a Odontologia e suas especialidades. A Odontologia digital e suas tecnologias associadas têm se destacado de forma progressiva, abordando desde os planejamentos restauradores de forma virtual, as impressões de modelos em impressora 3D e os métodos de confecção de próteses em fresadoras auxiliadas por computadores. Objetivo: este trabalho tem como objetivo realizar uma revisão de literatura, com uma abordagem conceitual e histórica acerca da Odontologia digital, do escaneamento intraoral e da confecção laboratorial das restaurações indiretas por meio dos sistemas CAD/CAM. Fonte dos dados: a pesquisa na literatura foi feita utilizando-se as bases de dados Medline® (PubMed), Scielo e Bireme com as seguintes palavras chaves: "CAD/CAM", "dental prothesis", "dental porcelain", "digital dentistry", "dental scanner", "digital impression". Síntese dos dados: os estudos demonstraram grandes avanços nas técnicas de moldagem com o escaneamento intraoral permitindo a obtenção de imagens fidedignas dos dentes e estruturas adjacentes de forma precisa, otimizando o tempo clínico. Além disto, o desenvolvimento de novos métodos e materiais dentários tem possibilitado a elaboração de modelos de trabalho, restaurações indiretas e infraestruturas de próteses por meio de um processo totalmente digital. Conclusão: podemos concluir que os estudos reportam resultados promissores com os métodos de trabalho por meio do fluxo digital. Além disso, é notável que esta realidade na Odontologia restauradora e reabilitadora continuará evoluindo e possibilitando o acesso a um maior número de profissionais.

Introduction: technological innovations are important and present an important role in various aspects in lives of individuals in society. Different areas of knowledge working with technological and digital tools, and among these areas, Dentistry and its specialties stand out. In the last decades, digital Dentistry and its associated technologies have been highlighting in a progressive way, approaching from the virtual restorative planning, 3D printed models to the prosthesis manufacturing methods in milling machines aided by computer. Objective: the aim of this study is to reach out a literature review, with a conceptual and historical approach about digital Dentistry, intraoral scanning and laboratory press of indirect restorations with CAD/CAM systems. Sources of data: the literature search was done using Medline® (PubMed), Scielo and Bireme databases with the following keywords: "CAD/CAM", "dental prothesis", "dental porcelain", "3D printing". Synthesis of data: the present work demonstrates a great advance in impression technique with intraoral scan allowing the obtention of trustworthy images from teeth and surrounding structures in a precision way, optimizing clinical time. Furthermore, the development of new methods and dental materials have been allowing the elaboration of dental work cast, indirect restorations and prosthesis infrastructures in a fully digital process. Conclusion: it is possible to conclude that the articles report promising results with working methods through the digital flow. Besides that, it is remarkable that this reality in restorative and rehabilitation dentistry will be in a continuous evolution and allowing access to a greater number of professionals.

Evaluation of customized peripheral sealing device acceptance for surgical/medical masks among dental professionals during early COVID-19 pandemic / Evaluación de la aceptación de dispositivos de sellado periférico personalizados para máscaras quirúrgicas/médicas entre dentistas durante la pandemia temprana de COVID-19

Abstract A 3-dimensional (3D) printed custom-frame can improve the peripheral seal of readily available surgical/medical masks. This study aimed to assess the acceptance of a 3D-printed custom-frame with the American Society for Testing and Materials (ASTM) surgical/medical masks and the use of a face shield. A total of 206 subjects from a dental school participated, who answered a multiple-choice questionnaire. Participants received an invitation through the institutional email of the school via Qualtrics platform. 3D printed custom-frames were fabricated for each participant. According to their response, participants were divided into 4 groups: mask only (M), mask and frame (MF), mask and face shield (MFS), and all 3 personal protective equipment (MFFS). Data was analyzed in absolute and relative frequency. The acceptance of a 3D-printed custom-frame in the group MFFS varied between ''poor''/''very poor'' (44.7%). It allowed ''good'' performance of routine procedures (40.3%), but ''poor'' visual quality (48.1%). Musculoskeletal tolerance and ease to perform movements were adequate. There was no interference in olfactory sensitivity (44.7%) or in the ability to breathe (34.5%). Finally, it showed "moderate pain" (48.1%) on the ear and "no pain" (38.9%) on the head. The 3D-printed custom-frame adapted to ASTM surgical/medical face masks showed reasonable tolerance. Side effects of ear pain ranging in degrees were noted. Further research is indicated to evaluate safety, comfort, compliance, side effects, and occupational hazards of long-term use of enhanced PPE recommendations.Avoiding the recurrent outbreaks of COVID-19, the use of PPE by the public is necessary. Improper PPE use is a major source of concern for human and environmental health. Preventing such activities can be done by following steps involved in PPE disposals or by getting a new way to re-use such as improving peripherical sealing. Our work highlights that a custom-frame can improve protection, without adverse effects.

Resumen El sellado periférico de las máscaras médicas/quirúrgicas puede ser mejorado fácilmente mediante un marco personalizado impreso en 3 dimensiones (3D). Este estudio tuvo como objetivo evaluar la aceptación de un marco personalizado impreso en 3D cuando usado en combinacion con máscaras médicas/quirúrgicas de la Sociedad Estadounidense para Pruebas y Materiales (ASTM) asi como con el uso de protector facial. Participaron un total de 206 sujetos de una facultad de odontología, quienes respondieron un cuestionario de opción múltiple. Los participantes recibieron una invitación a través del correo institucional de la escuela a través de la plataforma Qualtrics. Se fabricaron marcos personalizados impresos en 3D para cada participante. Según su respuesta, los participantes se dividieron en 4 grupos: solo máscara (M), máscara y marco (MF), máscara y protector facial (MFS) y los 3 equipos de protección personal (MFFS). Los datos se analizaron en frecuencia absoluta y relativa. La aceptación de un marco personalizado impreso en 3D en el grupo MFFS varió entre ''pobre''/''muy pobre'' (44,7%). Permitió un ''buen'' desempeño de los procedimientos de rutina (40,3%), pero una ''mala'' calidad visual (48,1%). La tolerancia musculoesquelética y la facilidad para realizar movimientos fueron adecuadas. No hubo interferencia en la sensibilidad olfativa (44,7%) ni en la capacidad de respirar (34,5%). Finalmente, mostró "dolor moderado" (48,1%) en el oído y "sin dolor" (38,9%) en la cabeza. El marco personalizado impreso en 3D adaptado a las máscaras faciales quirúrgicas/ médicas de ASTM mostró una tolerancia razonable. Se observaron efectos secundarios de dolor de oído que variaron en grados. Estudios futuros deben evaluar la seguridad, la comodidad, efectos secundarios y los riesgos laborales del uso a largo plazo para este tipo de combinación. Para evitar los brotes recurrentes de COVID-19, es necesario el uso de equipamento personal de protección (EPP) por parte del público. El uso inadecuado de EPP es una fuente importante de preocupación para la salud humana y ambiental. La prevención de tales actividades se puede hacer siguiendo los pasos involucrados en la eliminación de EPP o obteniendo una nueva forma de reutilización, como mejorar el sellado periférico. Nuestro trabajo resalta que un marco personalizado puede mejorar la proteccion, sin afectos adversos.

Comparative Study with and without the Use of 3D Prototyping of an Unconventional Technique in the Surgical Planning of Revision of Total Hip Arthroplasty / Estudo comparativo com e sem o uso de prototipagem em 3D de uma técnica não convencional no planejamento cirúrgico de revisão de artroplastia total de quadril

Abstract This article presents a comparison between two cases in which there was a need for revision of total hip arthroplasty due to aseptic acetabular failure. We used 3D prototyping in one of the cases to perform an unconventional technique of molding synthesis material before the procedure to evaluate the time saved in the transoperative period in complex cases.

Resumo Este artigo apresenta uma comparação entre dois casos em que havia a necessidade de revisão de artroplastia total de quadril por falha acetabular asséptica. Utilizamos prototipagem em 3D em um dos casos para realizar uma técnica não convencional de moldagem de material de síntese antes do procedimento, com objetivo de avaliar o tempo economizado no transoperatório em casos complexos.

Aplicación de modelos 3D en cirugía hepática / Implementation of three-dimensional printed models in hepatic surgery

RESUMEN La impresión de modelos tridimensionales (M3D) implica obtener una estructura sólida y formada a partir de un modelo digital. Para la reconstrucción 3D se utilizó tomografía computarizada contrastada, realizándose impresión de modelos sobre la base de las principales estructuras anatómicas hepáticas. Se utilizaron M3D en dos pacientes con indicación quirúrgica, una mujer con trombocitopenia familiar y metástasis hepática de adenocarcinoma rectal, sin respuesta a quimioterapia, y un hombre con hepatopatía infecciosa crónica y diagnóstico de carcinoma hepatocelular. La aplicación de M3D resultó de gran utilidad, pues permitió un mejor entendimiento de la relación espacial de las estructuras anatómicas en ambos casos. En nuestra experiencia, la aplicación de M3D fue muy útil para planificar la cirugía y dar una aproximación más certera de los reparos anatómicos. El modelo se obtuvo en 7 días y costó 380 dólares, un valor elevado para nuestro medio.

ABSTRACT Three-dimensional (3D) printing is the construction of a solid structure from a digital model. 3D reconstruction was performed using contrast-enhanced computed tomography scan, and 3D-printed models were built based on the main anatomic structures of the liver. 3D-printed models were used in two patients with indication of surgery; one woman with inherited thrombocytopenia and liver metastases from colorectal adenocarcinoma with no response to chemotherapy, and one man with chronic liver infection and hepatocellular carcinoma. The implementation of 3D printing technology was very useful, as it facilitated the understanding of the spatial relationships among the anatomical structures in both cases. In our experience, the use of 3D-printed models was very useful for preoperative planning and for understanding the anatomic landmarks. The model was built in 7 days, with a cost of 380 dollars which is elevated in our environment.

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)