Microtensile bond strength of resin cements to 3-D printed and milled temporary restorative resins / Resistencia de unión en microtracción de cementos resinosos a resinas para provisionales impresas y fresadas

Abstract To evaluate the microtensile bond strength (µTBS) of two resin cements to 3D printed and milled CAD/CAM resins used for provisional fixed partial dentures. Blocks (5 x 5 x 5 mm) of three 3D-printed resins (Cosmos3DTemp / Yller; Resilab3D Temp / Wilcos and SmartPrint BioTemp, / MMTech) were printed (Photon, Anycubic Technology Co.). A milled material (VitaCAD-Temp, VITA) was used as control. Half the specimens were sandblasted and the rest were untreated. Two blocks were bonded with the corresponding resin cement: PanaviaV5 (Kuraray Noritake) and RelyX Ultimate (3M Oral Care). After 24 hours, the bonded blocks were sectioned into 1 x 1 mm side sticks. Half the beams were tested for µTBS and the other half was thermocycled (5000 cycles, 30s dwell-time, 5s transfer time) before µTBS testing. A four way Generalized Linear Model (material*sandblasting*cement*aging) analysis was applied. VITA exhibited the lowest µTBS, regardless of the cement, sandblasting and thermocycling. Sandblasting significantly improved the µTBS of VIT, especially after aging, but did not improve the µTBS of 3D printed resins. Sandblasting was not beneficial for 3D printed resins, although is crucial for adhesive cementation of milled temporary resins. Airborne particle abrasion affects the integrity of 3D-printed resins, without producing a benefit on the microtensile bond strength of these materials. However, sandblasting is crucial to achieve a high bond strength on milled temporary resins.

Resumen Evaluar la resistencia adhesiva en microtracción (µTBS) de dos cementos resinosos a resinas CAD/CAM impresas y fresadas indicadas para restauraciones provisionales. Bloques (5 x 5 x 5mm) de tres resinas impresas (Cosmos3DTemp / Yller; Resilab3D Temp / Wilcos and SmartPrint BioTemp, / MMTech) y una resina fresada (VitaCAD-Temp, VITA) fueron fabricados. La mitad de los especímenes fueron arenados y el resto no recibió tratamiento mecánico. Dos bloques con condiciones de tratamiento iguales fueron cementados con cemento resinoso (PanaviaV5 / Kuraray Noritake y RelyX Ultimate / 3M Oral Care). Después de 24 horas los bloques fueron seccionados en palitos de 1 mm² de área. En la mitad de los especímenes se midió la TBS inmediatamente y el resto fue termociclado (5000 ciclos, 30s remojo, 5s transferencia) antes de la prueba de TBS. Se aplica un análisis estadístico por Modelo Linear General con 4 factores (material*arenado*cemento*termociclado). La resina VITA presentó la menor µTBS, independientemente del cemento usado, el arenado y el termociclado. Sin embargo, el arenado aumentó la µTBS de VIT, especialmente después del termociclado. Por otro lado, el arenado no resultó en un aumento significativo de la µTBS de las resinas impresas. El arenado no fue beneficiosos para las resinas impresas, aunque es un paso crucial para la cementación adhesive de las resinas fresadas. El arenado afecta la integridad de las capas de las resinas impresas, sin generar un beneficio en la TBS.

Anatomía de la cámara pulpar y sistema de conductos radiculares: Estrategias pedagógicas unarevisión de literatura / Anatomy of the pulp chamber and the root canal system: Pedagogical strategiesAliterature review

Antecedentes: El conocimiento anatómico de la cámara pulpar y del sistema de conductos radiculareses fundamental para el correcto diagnóstico y planificación del tratamiento en endodoncia. Las herramientas pedagógicasdirigidasa los estudiantes de odontologíacomo apoyo en los procesos formativosde la asignatura de endodoncia favorecen la apropiación del conocimiento e identificación de las variantes morfológicas del sistema de conductos radiculares, que permiten al estudiantela integración del conocimiento. Objetivo:Identificar mediante una revisión de la literatura las estrategias pedagógicas que se utilizan para la enseñanza de morfología del sistema de conductos radiculares en endodoncia. Materiales y métodos: Se realizó una búsqueda bibliográfica de estudios originales en las bases de datos Medline (Pubmed), SciELO, Lilacs, Medline (Ovid), Web of science, Scopus, Embase, Google académico, eligiendo estudios publicadosa partir del año 2010 al 2022, para la selección de los artículos definitivos se seleccionaron estudios concernientes a procesos pedagógicos en endodoncia, excluyendo así otros tipos de enfoques en el área de odontología. Resultados: Se identificaron un total de 63 referencias, los cuales fueron analizados y seleccionados16, siendo excluidos 47 por no cumplir los criterios de inclusión. Conclusión: El uso de herramientas pedagógicas virtuales, didácticas y tecnológicas propician un efecto positivo en el estudiante de pregrado de odontología durante el aprendizaje de anatomía de sistemas de conductos radiculares que aumentan la confianza y seguridad al momento de realizar un tratamiento endodóntico en pacientes

Background: Anatomical knowledge of the pulp chamber and the root canal system is essential for correct diagnosis and treatment planning in endodontics. The pedagogical tools aimed at dental students as support in the training processes of the endodontics subject favor the appropriation of knowledge and identification of the morphological variants of the root canal system, which allow the student the integration of knowledge. Objective: To identify, through a review of the literature, the pedagogical strategies used to teach morphology of the root canal system in endodontics. Materials and methods: A bibliographic search of original studies was carried out in the Medline (Pubmed), SciELO, Lilacs, Medline (Ovid), Web of Science, Scopus, Embase, and Google academic databases, choosing studies published from 2010 to 2022. , for the selection of the definitive articles, studies concerning pedagogical processes in endodontics were selected, thus excluding other types of approaches in the area of dentistry. Results: A total of 63 references were identified, 16 of which were analyzed and selected, 47 being excluded for not meeting the inclusion criteria. Conclusion: The use of virtual, didactic and technological pedagogical tools favor a positive effect on the dentistry undergraduate student while learning the anatomy of root canal systems that increase confidence and security when performing endodontic treatment in patients.

3D Printing characteristics and mechanical properties of a bio scaffold obtained from a Micro-CT Scan, using the fused deposition modeling technique

The objective is to determine which biopolymer has the best 3D printing characteristics and mechanical properties for the manufacture of a bioscaffold, using the fused deposition printing technique, with models generated from an STL file obtained from a Micro-CT scan taken from a bovine iliac crest bone structure. Through an experimental exploratory study, three study groups of the analyzed biopolymers were carried out with thirteen printed structures of each one. The first is made of 100% PLA. The second, 90B, we added 1g of diatom extract, and the third, 88C, differs from the previous one in that it also contains 1g of calcium phosphate. The 39 printed structures underwent a visual inspection test, which required the fabrication of a gold standard scaffold in resin, with greater detail and similarity to the scanned bone structure. Finally, the structures were subjected to a compressive force (N) to obtain the modulus of elasticity (MPa) and compressive strength (MPa) of each one of them. A statistically significant difference (p=0.001) was obtained in the printing properties of the biomaterial 88C, compared to 90B and pure PLA and the 88C presented the best 3D printing characteristics. In addition, it also presented the best mechanical properties compared to the other groups of materials. Although the difference between these was not statistically significant (p=0.388), in the structures of the 88C biomaterial, values of compressive strength (8,84692 MPa) and modulus of elasticity (43,23615 MPa) were similar to those of cancellous bone in the jaws could be observed. Because of this result, the 88C biomaterial has the potential to be used in the manufacture of bioscaffolds in tissue engineering.

El objetivo es determinar cuál biopolímero presenta las mejores características de impresión 3D y propiedades mecánicas para la fabricación de un bioandamiaje, utilizando la técnica de impresión por deposición fundida, con modelos generados a partir de un archivo en formato STL que se obtuvo de un Micro-CT Scan de una estructura osea de cresta iliaca bovina. Mediante un estudio exploratorio, se realizaron 3 grupos de estudio con trece estructuras impresas de cada uno. El primero, se compone 100% de PLA. El segundo, 90B, se le agrega 1g de extracto de diatomea, y el tercero, 88C, se diferencia del anterior ya que contiene además, 1g de fosfato de calcio. A las 39 estructuras impresas se les realizó una prueba de inspección visual, por lo que se requirió la confección de un patrón de oro en resina, con mayor detalle y similitud a la estructura ósea escaneada. Finalmente, las estructuras fueron sometidas a una fuerza compresiva (N) para la obtención del módulo de elasticidad (MPa) y de la resistencia compresiva (MPa) de cada una de ellas. Se obtuvo una diferencia estadísticamente significativa (p=0,001) en las propiedades de impresión del biomaterial 88C, con respecto al 90B y al PLA puro, presentando las mejores características de impresión 3D. Además, obtuvo las mejores propiedades mecánicas en comparación con los otros grupos de materiales. Aunque la diferencia entre estos no fue estadísticamente significativa (p=0,388), en las estructuras del biomaterial 88C, se pudieron observar valores de resistencia compresiva (8,84692 MPa) y módulo de elasticidad (43,23615 MPa) que son semejantes a los del hueso esponjoso de los maxilares. A razón de este resultado, el biomaterial 88C cuenta con el potencial para ser utilizado en la fabricación de bioandamiajes en la ingeniería tisular.

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.

Guided Endodontic Surgery ? Case Series

This case report describes three cases in which periapical surgeries were carried out using a new surgical endodontic technique by using a three?dimensional (3D) printed template for guided osteotomy and root resection. In Case 1, the data obtained from preoperative CT scan and cast scan were transferred to a surgical planning software. The surgical template was printed using a 3D printer. Using the template, osteotomy and root?end resection were precisely carried out. In Case 2, after CBCT imaging, data were transferred to stereolithography and a 3D model was fabricated. With the help of the 3D model, a template was fabricated using tray material. This guided surgical template minimized the extent of osteotomy and enabled precise targeting of the apex. In Case 3, a preoperative CT scan aided in the fabrication of a surgical 3D template. The template assisted in the precise removal of the overlying cortical bone.

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.

Assessment of 3D-printed tissue compensators for superficial tumor X-ray radiation compensation / 中华放射医学与防护杂志

Objective:To investigate the advantage of three dimensional(3D)-printed tissue compensators in radiotherapy for superficial tumors at irregular sites.Methods:A subcutaneous xenograft model of prostate cancer in nude mice was established. Mice were randomly divided into no tissue compensator group( n=6), common tissue compensator group( n=6), and 3D-printed tissue compensator group( n=6). Computed tomography (CT) images of nude mice in the 3D-printed tissue compensator group were acquired. Compensator models were made using polylactic acid, and material properties were evaluated by measuring electron density. CT positioning images of the three groups after covering the corresponding tissue compensators were acquired to delineate the gross tumor volume (GTV). Nude mice in the three groups were irradiated with 6 MV X-rays at the prescribed dose. The prescribed dose for the three groups was 1 500 cGy. The dose distribution in the GTV of the three groups was calculated and compared using the analytical anisotropic algorithm in the Eclipse 13.5 treatment planning system. The metal-oxide-semiconductor field-effect transistor was used to verify the actual dose received on the skin surface of nude mice. Results:The air gap in the 3D-printed tissue compensator group and the common tissue compensator group was 0.20±0.07 and 0.37±0.07 cm 3, respectively ( t=4.02, P<0.01). For the no tissue compensator group, common tissue compensator group, and 3D-printed tissue compensator group, the D95% in the target volume was (1 188.58±92.21), (1 369.90±146.23), and (1 440.29±45.78) cGy, respectively ( F=9.49, P<0.01). D98% was (1 080.13±88.30), (1 302.76±158.43), and (1 360.23±48.71) cGy, respectively ( F=11.17, P<0.01). Dmean was (1 549.08±44.22), (1 593.05±65.40), and (1 638.87±40.83) cGy, respectively ( F=4.59, P<0.05). The measured superficial dose was (626.03±26.75), (1 259.83±71.94), and (1 435.30±67.22) cGy, respectively ( F=263.20, P<0.001). The percentage variation in tumor volume growth after radiation was not significantly different between the common tissue compensator group and the 3D-printed tissue compensator group ( P>0.05). Conclusions:3D-printed tissue compensators fit well to the body surface, which reduces air gaps, effectively increases the dose on the body surface near the target volume, and provides ideas for radiotherapy for superficial tumors at some irregular sites.

3D-PCT-assisted CT-guided radioactive particle implantation precision / 中华放射医学与防护杂志

Objective:To study the precision of 3D printing coplanar template (3D-PCT) assisted CT-guided radioactive particle implantation using two types of phantoms, and compare the differences between the phantoms, in order to provide reference for radioactive particle implantation.Methods:The needle inserting path was designed in the brachytherapy treatment planning system (BTPS) and the needle tip coordinates were obtained. Following the needle inserting path, the implant needles were inserted into the custom and the liver phantoms, respectively. Then gold markers were implanted through the needles. Subsequently, the needles were withdrawn by 10 mm, and the cold sources were implanted. The coordinates of needle tips, gold markers, and cold sources were recorded. The precision of implanted needles, first particles, and particles after needle withdrawal were obtained by calculating the distance between two points in the space. Finally, the differences between the two phantoms were compared through independent samples t-test. Results:In the 3D-PCT-assisted CT-guided radioactive particle implantation, the precision of implanted needles, first particles, and particles after needle withdrawal in the custom and the liver phantoms was (1.89±0.72) and (2.14±0.88 ) mm ( P>0.05), (2.03±1.14) and (2.42±1.12) mm ( P>0.05), and (-1.96±1.29) and (-2.82±0.91) mm ( t=2.09, P=0.046), respectively. Conclusions:The 3D-PCT-assisted CT-guided radioactive particle implantation is efficient, stable, and precise, showing slight precision differences between the two phantoms.

Advances in 3D printing-based body membrane immobilization technology in radiotherapy / 中华放射医学与防护杂志

The widespread application of 3D printing and computer technologies in the medical field has opened up opportunities for digital and automated fabrication of body immobilization tools for radiotherapy, thus making it possible to get rid of the original complex manual fabrication process. As the most widely used technique for body immobilization, body membrane immobilization has always attracted much attention. This review outlines the development of the body membrane immobilization technology in different radiotherapy stages. Moreover, the advances in the application of 3D-printed body membranes were introduced, as a development direction of body immobilization technology, in the field of radiotherapy. This technology can be utilized as a reference for clinical application and research.

3D-printing-assisted surgery versus conventional surgery for treatment of Schatzker VI tibial plateau fractures: a multi-center clinical study / 中华创伤骨科杂志

Objective:To compare 3D-printing-assisted surgery and conventional surgery in the treatment of Schazker type Ⅵ tibial plateau fractures.Methods:A retrospective study was conducted to analyze the clinical data of 50 patients with type Ⅵ tibial plateau fracture who had been treated from January 2019 to December 2021 at the 5 Departments of Orthopedics in The First Affiliated Hospital of Nanchang University, The First People's Hospital of Jiujiang, Pingkuang General Hospital, Ganzhou People's Hospital, and Nanchang Hongdu Hospital of Traditional Chinese Medicine. The patients were divided into 2 groups according to their different treatment methods. In the 3D printing group of 25 cases treated by 3D-printing-assisted surgery, there were 14 males and 11 females, with an age of (42.5±9.1) years; in the conventional group of 25 cases treated by conventional surgery, there were 13 males and 12 females with an age of (42.2±9.3) years. The 2 groups were compared in terms of operation time, intraoperative blood loss, intraoperative fluoroscopy frequency, fracture healing time, postoperative complications, the Rasmussen radiological scores and the American Hospital for Special Surgery (HSS) knee function scores at 6 and 12 months after operation.Results:There was no significant difference in the preoperative general data between the 2 groups, indicating comparability ( P>0.05). The operation time [(125.4±10.6) min], intraoperative blood loss [(206.2±16.3) mL], intraoperative fluoroscopy frequency [(9.2±2.7) times] and fracture healing time [(3.0±0.7) months] in the 3D printing group were all significantly less than those in the conventional group [(168.2±14.1) min, (303.2±20.4) mL, (15.5±3.5) times and (4.1±0.8) months] while the Rasmussen radiological scores (17.6±1.2 and 17.9±0.6) and HSS knee scores (90.8±6.4 and 91.5±5.6) at 6 and 12 months after operation in the 3D printing group were all significantly higher than those in the conventional group (16.2±2.6 and 16.7±2.2; 84.5±9.2 and 87.6±8.0) (all P<0.05). In the 3D printing group, there were 1 case of wound infection and 1 case of wound dehiscence after operation. In the conventional group, there were 2 cases of wound skin necrosis, 3 cases of wound dehiscence, 1 case of traumatic arthritis, 2 cases of wound infection, and 1 case of screw loosening. The incidence of complications in the 3D printing group (8.0%, 2/28) was significantly lower than that in the conventional group (36.0%, 9/25) ( P<0.05). Conclusion:In the treatment of Schatzker type VI tibial plateau fractures, compared with conventional surgery, 3D-printing-assisted surgery can lead to better curative outcomes, because it is conducive to lowering surgical difficulty, reducing postoperative complications, and promoting fracture union and functional recovery of the knee.

Fixation with a 3D printed individualized custom-made plate for elderly patients with periprosthetic femoral fracture: an analysis of short-term efficacy / 中华创伤骨科杂志

Objective:To explore the short-term efficacy of fixation with a 3D printed individualized custom-made plate in the treatment of elderly patients with periprosthetic femoral fracture.Methods:Retrospectively analyzed were the 5 elderly patients with periprosthetic femoral fracture who had been treated by fixation with a 3D printed individualized custom-made plate from January 2022 to July 2022 at Department of Orthopaedics and Traumatology, Beijing Jishuitan Hospital. There were 3 males and 2 females, aged 81, 86, 77, 91 and 87 years, respectively. One left and 4 right limbs were affected. Vancouver classification: type B1 ( n=3), type B2 ( n=1), and type C ( n=1). The time from operation to injury was 5, 6, 10, 5 and 7 days, respectively. Preoperatively, the femur affected, prosthesis and individualized plate with a greater trochanteric hook, loop cable channel and bone-like trabecular microporous structure were custom-made by 3D printing according to 1:1 models. Virtual operations were simulated to formulate surgical protocols. The operation time, length of surgical incision, intraoperative blood loss and transfusion, hospital stay, hip function and complications at the last follow-up were recorded. Results:The 5 patients were followed up for 12, 7, 10, 3 and 6 months, respectively. There were no events of superficial incision or deep prosthesis infection. Respectively, the operation time was 1.8, 1.7, 2.3, 2.0 and 3.3 h; the length of surgical incision 31, 30, 38, 27 and 30 cm; the intraoperative bleeding volume 400, 300, 300, 500 and 600 mL; the length of hospital stay 8, 9, 15, 14 and 11 d. Four patients received intraoperative blood transfusion of 300, 900, 150 and 1, 050 mL, respectively. One patient died of a heart attack 3 months after discharge; another patient developed dyskinesia at the contralateral limb 3 months after discharge due to cerebral infarction and died of recurrent cerebral infarction 7 months after discharge. At the last follow-up, the Harris hip scores of 3 patients were 86, 77 and 69 points, respectively. None of the patients had complications like breakage or loosening of implants.Conclusion:In the treatment of elderly patients with periprosthetic femoral fracture, fixation with a 3D printed individualized custom-made plate may lead to fine limb function and good short-term curative efficacy.

Application of digital 3D printed model combined with case-based learning in practice teaching of oral and maxillofacial surgery / 中华医学教育探索杂志

Objective:To investigate the application effect of the combined teaching model of digital 3D printed model and Tencent conference in case-based learning (CBL) teaching of oral and maxillofacial surgery.Methods:A total of 80 undergraduates in the classes of 2015 and 2016 were selected from School of Stomatology, Qingdao University. The students in the class of 2015 received traditional teaching, and those in the class of 2016 received the combined CBL teaching model of 3D printed model and Tencent conference. A questionnaire survey was used to evaluate the teaching effect, and theoretical examination was used to assess comprehensive abilities of the two groups. SPSS 24.0 was used to perform the chi-square test and the t-test. Results:There was no significant difference in the degree of satisfaction with teaching between the combined CBL teaching model of 3D printed model and Tencent conference and the traditional teaching model ( P>0.05), and both models were generally recognized and accepted by students. The experimental group had a significantly higher score than the control group (94.05±4.16 vs. 86.10±3.37, P<0.05). Conclusion:The combined teaching model of digital 3D printed model and Tencent conference integrates the advantages of the Internet and digital information and thus provides a certain reference for the teaching methods for other majors in stomatology.

Application of 3D virtual reconstruction and printing technology based on thin-slice CT images in network cloud+dual-track teaching / 中华医学教育探索杂志

Objective:To investigate the application prospect of 3D virtual reconstruction and printing technology based on thin-slice CT images in network cloud+dual-track teaching.Methods:A total of 120 medical students who were on probation in The Second Affiliated Hospital of Air Force Medical University from April 2021 to April 2022 were selected as subjects and were randomly divided into experimental group and control group, with 60 students in each group. The students in the experimental group received 3D virtual reconstruction and printing technology combined with network cloud+dual-track teaching, and those in the control group received network cloud+dual-track teaching alone. After 6 months of learning, the teaching effect was compared by closed-book examination, skill operation, speech defense, and questionnaire survey. SPSS 23.0 was used for the t-test and the chi-square test. Results:Compared with the control group in terms of department examination, the experimental group had significantly better scores of theoretical knowledge [(84.25±5.53) vs. (79.43±6.69), P<0.001] and operational skills [(87.68±5.72) vs. (82.97±5.32), P<0.001]. The experimental group had significantly higher scores than the control group in speech [(44.90±2.56) vs. (41.88±2.71), P<0.001] and defense [(45.83±2.62) vs. (43.85±2.56), P<0.001]. The questionnaire survey showed that compared with the control group, the experimental group had significantly higher scores of practical ability, active learning ability, expression ability, practice enthusiasm, and information acquisition ability ( P<0.001). Conclusion:The network cloud+dual-track teaching model assisted by 3D virtual reconstruction and printing technology can significantly improve the objective learning effect and subjective learning initiative of students and has a relatively high value of teaching application and promotion.

Application of 3D digital modeling combined with 3D printed model in classroom theoretical teaching of orthopedics / 中华医学教育探索杂志

Objective:To investigate the application effect of 3D digital modeling combined with 3D printed model in assisting the classroom theoretical teaching of orthopedics in five-year undergraduate students majoring in clinical medicine.Methods:In May 2022, 33 five-year undergraduate students majoring in clinical medicine in the class of 2018 in Southwest Medical University were selected and divided into experimental group with 17 students and control group with 16 students according to the odd or even student number. The students in the experimental group were taught by traditional PPT+3D digital modeling combined with 3D printed model, and those in the control group were taught by the traditional PPT teaching method. The teaching effect was evaluated by theoretical examination and a questionnaire survey on the degree of satisfaction with teaching. SPSS 25.0 was used to perform the t-test, the Mann-Whitney U test, the rank sum test, and the chi-square test. Results:The experimental group had a significantly higher score of theoretical examination than the control group (86.24±4.16 vs. 82.50±6.06). The questionnaire survey on the degree of satisfaction with teaching showed that compared with the control group, the experimental group had a significantly higher degree of satisfaction with the understanding and learning of orthopedic diseases [3 (2, 3) vs. 2 (2, 2), P < 0.05], the improvement in learning interest [2 (2, 3) vs. 2 (1, 2), P < 0.05], classroom innovation [3 (3, 3) vs. 2 (1.5, 2), P < 0.05], and overall classroom teaching [3 (2, 3) vs. 2 (2, 2), P < 0.05]. Conclusion:In assisting the classroom theoretical teaching of orthopedics in undergraduate students majoring in clinical medicine, 3D digital modeling combined with 3D printed model can provide concrete 3D models, reduce the difficulties in learning, improve the awareness of orthopedic diseases, strengthen learning interest, and increase the degree of satisfaction with teaching and academic scores.

Study on the application effects of the mode of "Multidisciplinary integration, Doctors & patients co-teaching, Simulated practice" in the teaching of spinal surgery / 中华医学教育探索杂志

Objective:To explore the application effects of the mode of "Multidisciplinary integration, Doctors & patients co-teaching, Simulated practice" in the teaching of spinal surgery.Methods:A total of 64 eight-year program clinical medical students who practiced in Peking Union Medical College Hospital in 2021 were taken as research objects and randomly divided into experimental group ( n=33) and control group ( n=31). The experimental group received the new teaching mode of "Multidisciplinary integration, Doctors & patients co-teaching, Simulated practice", and the control group received regular teaching mode. At the end of teaching, the teaching effects were evaluated from several aspects, including the scores of theoretical examinations, anatomical marks identification tests, and anonymous questionnaires. SPSS 22.0 software was used for paired t-test and two independent-samples t-test. Results:The theoretical test scores [(51.25±6.99) points] and anatomical structure identification scores [(37.56±1.83) points] of the experimental group were higher than those of the control group [(42.46±6.13) points and (30.37±3.46) points], and the differences were statistically significant ( P<0.001). The effective recovery rate of the questionnaire was 100%. The results of the questionnaire showed that the experimental group was significantly higher than the control group in terms of teaching attractiveness, attention, learning interest, learning efficiency, anatomical identification ability, problem-finding and problem-solving ability and overall teaching method satisfaction ( P<0.05). Conclusion:The teaching mode of "Multidisciplinary integration, Doctors & patients co-teaching, Simulated practice" can effectively improve students' theoretical knowledge, learning interest, learning efficiency, operation proficiency and problem-finding and problem-solving ability, which is worth promoting.

Application of CBL combined with 3D printing teaching in clinical teaching of sacral tumors / 中华医学教育探索杂志

Objective:To explore the application effect of case-based learning (CBL), teaching mode combined with 3D printing in clinical teaching of sacral tumors.Methods:A total of 108 undergraduate interns and standardized residency training students who studied in our hospital from 2017 to 2018 were divided into the CBL teaching group ( n = 53) and the CBL combined with 3D printing teaching group ( n = 55) according to their study time. The combined teaching group used computer tomography (CT) data to reconstruct and print out a 3D model of sacral tumors based on CBL, and performed preoperative teaching on the invasion of the surrounding tissues of the tumor. The scores of the students in the two groups were evaluated respectively, and the students were surveyed by self-identification questionnaire (learning interest, self-learning ability, teamwork ability, comprehensive analysis ability and clinical thinking ability). The t-test (one-sided) was used for comparison between groups using stata 14.0. Results:The score of CBL teaching group (75.90±6.70) was lower than that of CBL combined with 3D printing teaching group (83.60±7.40). In terms of critical thinking ability evaluation, self-learning ability, learning interest, comprehensive analysis ability and clinical thinking ability, the CBL combined 3D printing teaching group was superior to the CBL teaching group, and the difference was statistically significant ( P<0.001). In terms of teamwork ability, there was no statistical difference between the two groups. Conclusion:The CBL teaching mode combined with 3D printing can improve academic performance, students' learning interest and clinical thinking ability of sacral tumors in the teaching of undergraduate interns and standardized residency training students.

Research progress of artificial intelligence in 3D printed drugs / 药学学报

In 2015, the United States put forward the concept of precision medicine, which changed medical treatment from "one size fits all" to personalization, and paid more attention to personalization and drug customization. In the same year, Spritam®, the world's first 3D printed tablet, was in the market, marking the emerging pharmaceutical 3D printing technology was recognized by regulatory authorities, and it also provided a new way for drug customization. 3D printing technology has strong interdisciplinary and high flexibility, which puts forward higher requirements for pharmaceutical staffs. With the development of artificial intelligence (AI), modern society can perform various tasks, such as disease diagnosis and robotic surgery, with superhuman speed and intelligence. As a major AI technology, machine learning (ML) has been widely used in many aspects of 3D printing drug, accelerating the research and development, production, and clinical application, and promoting the new process of global personalized medicine and industry 4.0. This paper introduces the basic concepts and main classifications of 3D printing drug, non-AI drug optimization technology and ML. It focuses on the analysis of the research progress of ML in 3D printing drug, and elucidates how AI can empower the intelligent level of 3D printing drug in pre-processing, printing, and post-processing process. It provides a new idea for accelerating the development of 3D printed drug.

3D printed orthopedic insoles for flatfoot: a systematic review / 中国康复理论与实践

ObjectiveTo review the classification of orthopedic insoles, common techniques of 3D printing orthopedic insoles, common materials and their application for flatfoot. MethodsLiteratures were retrieved from PubMed, Web of Science, CNKI and Wanfang Data from 2012 to 2022, and the relevant contents were summarized. ResultsA total of ten studies were finally included, from 5 countries, involving 290 participants, which published from 2019 to 2022. Orthotic insoles were classified as prefabricated, semi-custom, and custom, while custom ones were classified as traditional custom and 3D printed custom. 3D printed orthotic insoles were often made with selective laser sintering, fused deposition modeling (FDM) and PolyJet printing technologies, and commonly used materials included ethylene-vinyl acetate (EVA), polylactic acid, thermoplastic polyurethane, polyamide, and polypropylene. For flatfoot, 3D printed orthotic insoles could improve plantar pressure, relieve foot pain and the combined use of insole posting could control rearfoot valgus. Conclusion3D printed custom insoles can be made more efficiently and accurately than traditional custom insoles. The printing technologies and materials often chosen for 3D printed orthotic insoles are mainly FDM and EVA. 3D printed orthotic insoles is effective on plantar pressure, comfort and foot movement function of flatfoot.

Corrective effect of 3D printed scoliosis orthoses / 中国康复理论与实践

ObjectiveTo investigate the in-brace and short-term correction of 3D-printed scoliosis orthoses. MethodsFrom July to December 2021, 36 patients with adolescent idiopathic scoliosis from Ninth People's Hospital, Shanghai Jiaotong University School of Medicine were selected to complete full-length radiographs of the spine before and immediately after wearing the orthosis. They wore the orthosis more than 20 hours a day, and took radiographs six months later. Cobb angle was calculated. They were assessed with Chinese version of the Scoliosis Research Society's outcomes instrument 22 (SRS-22) before wearing and six months follow-up. ResultsThe mean Cobb angle was (22.10±6.29)° before wearing, and it was (7.85±10.90)° immediately after wearing (t = 4.775, P < 0.01) and (14.33±0.74)° six months follow-up (t = 4.189, P < 0.01). The score of functional status of SRS-22 increased six months follow-up (Z = -2.676, P < 0.01). The Cobb angle immediately after wearing correlated with the Cobb angle six months follow-up (r = 0.826, P < 0.05). Conclusion3D-printed scoliosis orthoses can correct the scoliosis satisfactorily, in-brace and in short-term.

Application of improved 3D digital guide plate-assisted guided puncture in microballoon compression for primary trigeminal neuralgia / 口腔疾病防治

Objective @#To investigate the clinical efficacy and application value of an improved 3D-printed guide plate for the treatment of primary trigeminal neuralgia (PTN) by percutaneous microballoon compression (PMC). @*Methods @# This prospective study included 42 patients with primary trigeminal neuralgia treated at the Department of Stomatology, Xuzhou Central Hospital, from September 2019 to January 2022. The group was divided by the random number table method into the experimental group (adopting 3D printing technology to make guide plates to guide the puncture, 22 cases) and the control group (adopting the traditional Hartel anterior approach to position the puncture, 20 cases). The intraoperative success rate of the first puncture, puncture time, operative time, radiation exposure of patients and postoperative complications were compared between the two groups. Postoperative Barrow Neurological Institute Scale (BNI) scores, facial numbness, diminished corneal reflexes and chewing weakness were recorded. The t-test, rank-sum test and chi-square test were used for statistical analysis, with P<0.05 indicating a statistically significant difference. @*Results @#The experimental group was significantly better than the control group in terms of the success rate of the first puncture (χ2 = 21.51, P<0.001), puncture time (Z = -5.51, P<0.001), operative time (t = 9.37, P<0.001), and the number of C-arm scans (Z = -4.59, P<0.001). Postoperative BNI scores of the experimental group included 21 cases of grade Ⅰ (91.5%) and 1 case of grade Ⅱ, while the control group included 17 cases of grade Ⅰ (85.0%), 2 cases of grade Ⅱ (10.0%) and 1 case of grade Ⅲ (5.0%), with no statistical significance (P>0.05). In the experimental group, 16 patients had postoperative masseter weakness, 1 had keratitis and 10 had perilabial herpes, while in the control group, 18 patients had postoperative masseter weakness, 2 had keratitis, 11 had perilabial herpes and 1 had monocular blindness. There was no significant difference in postoperative complications between the two groups (P>0.05). At 12 months of follow-up, there was no recurrence in either the experimental or control group. @* Conclusions @#3D digital guide plate-guided percutaneous microballoon compression for primary trigeminal neuralgia can improve the accuracy and safety of puncture to a certain extent, obviously shorten the operation time, reduce radiation exposure of the patients, improve the success rate of the operation, meaning it has a high clinical application value.