Three-dimensional Printing Model Research Articles

Digital design combined with endoscopic minimally invasive extraction of impacted mandibular third molars with roots in contact with the mandibular canal

Objective: To study the clinical efficacy of digital design combined with three-dimensional (3D) printing model minimally invasive extraction of complex impacted mandibular third molars. Methods: Eight patients who visited the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology from April 2023 to March 2024 were included, including 3 males and 5 females, aged from 27 to 57 years old. The impacted mandibular third molars of all patients were closely related to the mandibular canal, and part of the dental tissue entered the mandibular canal. Preoperative digital design was used to simulate the intraoperative tooth segmentation and bone removal operation of the power system and the segmented tooth dislocation path, and analyze the tooth extraction resistance. The mandibular teeth, mandibular canal and mandibular model were three-dimensionally printed using light-curing resin inkjet. During the operation, an endoscope was used combined with the 3D printed model to minimally invasively extract the impacted mandibular third molar. Quantitative sensory testing of the patient's lower lip skin on the operated side was performed before surgery, 2 days after surgery, and 7 days after surgery. Clinical data such as operation time were collected. A paired sample t test was performed on the 2 and 7 days postoperative data and the preoperative data to compare the data differences. Results: All 8 patients successfully completed preoperative design, model printing and minimally invasive surgery. The number of teeth segmented in the preoperative design was (4.4±1.3), and the number of teeth segmented in the actual operation was (4.0±1.1). The operation time was (33.3±13.0) min. None of the patients had postoperative numbness of the lower lip or other postoperative complication. It was observed endoscopically that the inferior alveolar neurovascular bundle was exposed in the extraction socket during the operation. The patient's pressure pain threshold 2 days after surgery (0.601±1.170) was significantly lower than before surgery (1.251±1.109) (t=2.83, P=0.025). Conclusions: For complicated impacted mandibular third molars, digital design combined with 3D printing model can be used to perform minimally invasive extraction with the assistance of an endoscope.

Neuroendoscopy Training

AbstractNeuroendoscopy can be learnt by assisting or doing live human surgery, cadaver dissection with or without augmented pulsatile vessel and cerebrospinal fluid (CSF) perfusion, and practicing on live animal, dead animal model, synthetic models, three-dimensional printing model with or without augmentation with animal, cadaver tissue, pulsatile vessel and reconstructed CSF model, virtual reality (VR) simulator, and hybrid simulators (combined physical model and VR model). Neurosurgery skill laboratory with basic and advanced learning should be there in all teaching hospitals. Skills can be transferred from simulation model or VR to cadaver to live surgery. Staged learning (first with simple model to learn basic endoscopic technique, then animal model, and then augmented cadavers) is the preferred method of learning. Although most surveys favor live surgery and practice on animal models and cadavers as the most preferred training model now, in future VR may also become a favored method of learning. This article is based on our experience in over 10,000 neuroendoscopic surgeries, and feedback from over 950 neuroendoscopic fellows or consultants who attended workshops conducted every 6 monthly since 2010. A literature search was done on PubMed and Google Scholar using (neuroendoscopy) AND (learning), and (neuroendoscopy) AND (training), which resulted in 121 and 213 results, respectively. Out of them, 77 articles were finally selected for this article. Most of the training programs typically focus on microneurosurgical training. There is lack of learning facilities for neuroendoscopy in most centers. Learning of neuroendoscopy differs greatly from microneurosurgery; switching from microneurosurgery to neuroendoscopy can be challenging. Postgraduate training centers should have well-equipped neuroendoscopy skill laboratory and the surgical educational curriculum should include neuroendoscopy training. Learning endoscopy is about taking advantages of the technique and overcoming the limitations of endoscopy by continuous training.

The Bony Nasal Cavity and Paranasal Sinuses of Big Felids and Domestic Cat: A Study Using Anatomical Techniques, Computed Tomographic Images Reconstructed in Maximum-Intensity Projection, Volume Rendering and 3D Printing Models.

This study aims to develop three-dimensional printing models of the bony nasal cavity and paranasal sinuses of big and domestic cats using reconstructed computed tomographic images. This work included an exhaustive study of the osseous nasal anatomy of the domestic cat carried out through dissections, bone trepanations and sectional anatomy. With the use of OsiriX viewer, the DICOM images were postprocessed to obtaining maximum-intensity projection and volume-rendering reconstructions, which allowed for the visualization of the nasal cavity structures and the paranasal sinuses, providing an improvement in the future anatomical studies and diagnosis of pathologies. DICOM images were also processed with AMIRA software to obtain three-dimensional images using semiautomatic segmentation application. These images were then exported using 3D Slicer software for three-dimensional printing. Molds were printed with the Stratasys 3D printer. In human medicine, three-dimensional printing is already of great importance in the clinical field; however, it has not yet been implemented in veterinary medicine and is a technique that will, in the future, in addition to facilitating the anatomical study and diagnosis of diseases, allow for the development of implants that will improve the treatment of pathologies and the survival of big felids.

The Use of 3D Printing in Fetal Surgery for Surgical Planning: A Scoping Review.

Objectives: We sought to identify in which clinical scenarios 3D printed models are used to plan for fetal surgeries as well as the main purpose and the imaging method utilized for the models. In addition, we describe benefits and shortcomings of the models, as well as potential future improvements. Methods: In this scoping review, data were collected retrospectively from scientific databases (PubMed, Embase, Cochrane CENTRAL, CINAHL, Scopus, and the Web of Science platform) and screened by title, abstract, and full text against strict criteria. The inclusion criteria required the study be performed on a live fetus and involve 3D models used for fetal surgery. The models must have been designed from diagnostic imaging modalities such as CT, MRI, or ultrasound. The articles considered include clinical trials, review articles, cohort studies, case series, case reports, and conference abstracts. Results: Of the initial 742 articles collected, six met the inclusion criteria. Spina bifida and EXIT procedures were the most frequent use cases that inspired surgeons to print models for surgical planning. The ability to view patient-specific anatomy in a 3D handheld model was often touted as providing a great benefit to the surgical team's ability to anticipate intraoperative challenges. Conclusions: Three-dimensional printing models have been applied to plan for fetal surgeries, more specifically, for EXIT procedures and fetoscopic surgical repair of spina bifida. The potential benefits of 3D printing in fetal surgery are enormous.

Dimensional Accuracy of Different Three-Dimensional Printing Models as a Function of Varying the Printing Parameters.

Even in digital workflows, models are required for fitting during the fabrication of dental prostheses. This study examined the influence of different parameters on the dimensional accuracy of three-dimensionally printed models. A stereolithographic data record was generated from a master model (SOLL). With digital light processing (DLP) and stereolithography (SLA) printing systems, 126 models were produced in several printing runs-SolFlex350 (S) (DLP, n = 24), CaraPrint 4.0 (C) (DLP, n = 48) and Form2 (F) (SLA, n = 54)-and their accuracy was compared with plaster and milled polyurethane models. In addition to the positioning on the build platform, a distinction was made between parallel and across arrangement of the models to the printer's front, solid and hollow models, and printing with and without support structures. For accuracy assessment, five measurement sections were defined on the model (A-E) and measured using a calibrated digital calliper and digital scans in combination with the GOM Inspect Professional software 2021. The mean deviation between the measurement methods for all distances was 79 µm. The mean deviation of the models from the digital SOLL model were 207.1 µm for the S series, 25.1 µm for the C series and 141.8 µm for the F series. While positioning did not have an influence, there were clinically relevant differences mainly regarding the choice of printer, but also individually in alignment, model structure and support structures.

A comparative investigation of three-dimensional printing models (rapid prototyping) made by imaging systems including multidetector computed tomography and cone-beam computed tomography systems

Abstract Introduction: Biomedical models (rapid prototyping) had a vast use in maxillofacial diagnosis and surgeries. Using this technology can lead to improvement in preoperative treatment planning and an increase in surgery quality. In this study, we investigated and compared the models derived from multidetector computed tomography (MDCT) and cone-beam computed tomography (CBCT) radiography systems. Aim: In this study, we investigated and compared the models derived from MDCT and CBCT radiography systems to see which is the most accurate. Materials and Methods: Five dried human mandibles were chosen in this study. These landmarks were chosen to investigate the reproduction ability: mental foramen, genial tubercle, central incisor, alveolar crest edge to the inferior mandibular border in midline, two bone defects in approximate dimensions of 3 × 3 mm2, first molar socket depth in the mesiobuccal line angle, mesiodistal length of tooth socket bone at the buccal and buccolingual width of tooth socket bone at mesial. Radiographs were taken using one MDCT and two CBCT systems. Then, models were built through a three-dimensional (3D) printer, and the mentioned landmarks were measured using a digital caliper. Data were entered in SPSS version 23 software and were analyzed with the ANOVA and Tukey tests. Results: In the reproduction of superior-inferior dimension and mesiodistal width of all mentioned landmarks, there were no significant differences between models made by data derived from Cranex 3D and NewTom 3G with a small field of view, in comparison with the gold standard (P > 0.05). However, there is a significant difference in the reproduction of landmarks between models made from MDCT and NewTom 3G with a large field of view, in comparison with the gold standard (P < 0.05). Conclusion: Models made from CBCT Devices with a small field of view have an acceptable and reliable accuracy for assessing bone structures. However, for CBCT devices with a large field of view and computed tomography-scan devices, models have less accuracy.

Three-dimensional printing versus traditional surgery for inveterate pelvic and acetabular fractures: A retrospective study of 37 patients.

Treatment of deformed pelvic and acetabular fractures is a considerable challenge for orthopedic surgeons. The aim of this study was to assess the availability of a three-dimensional (3D) printing model used in patients with inveterate pelvic and acetabular fractures by comparing 3D printing technology with conventional surgery. We conducted a retrospective review of patients with inveterate pelvic and acetabular fractures treated in our department between January 2008 and June 2020. The patients were divided into 2 groups according to their willingness. Perioperative data and clinical outcomes were compared to evaluate clinical efficacy. The t-test, Fisher exact test, and multivariable logistic regression analysis were conducted. A P value of .05 or less was considered to be statistically significant (two-tailed). Thirty-seven patients were enrolled in our study. Seventeen patients were divided into the case group treated by 3D printing model-assisted preoperative planning, and 20 patients were divided into the control group treated by conventional surgery. Patients treated with the 3D printing model had significantly shorter operation times, less blood loss, and shorter fluoroscopy times. Patients in the case group also showed better pain relief according to visual analog scale scores. However, the elevations in pelvis and hip joint functional outcomes were similar between the 2 groups, and no significant difference was shown in the radiological result. The usage of 3D printing techniques in patients with inveterate pelvic and acetabular fractures is of great importance in preoperative preparation and optimization of surgery but cannot improve postoperative function compared with conventional treatment.

Varicose vein three-dimensional printing model from duplex scan analysis images

Varicose vein three-dimensional printing model from duplex scan analysis images

3D printing of foetal vascular rings: feasibility and applicability

BackgroundVascular rings (VRs) exhibit complex and diverse forms that are difficult to conceptualize using traditional two-dimensional (2D) schematic. Inexperienced medical students and parents who lack a medical technology background face significant challenges in understanding VRs. The purpose of this research is to develop three-dimensional (3D) printing models of VRs to provide new technical imaging support for medical education and parental consultation.MethodsThis study included 42 fetuses diagnosed as VRs. Foetal echocardiography, modeling and 3D printing were performed, and the dimensional accuracy of models was analyzed. The value of 3D printing in the teaching of VRs was analyzed based on comparing the test results before and after the teaching intervention of 48 medical students and the satisfaction survey. A brief survey was conducted to 40 parents to assess the value of the 3D printed model in prenatal consultations.ResultsForty models of VRs were successfully obtained, which reproduced the anatomical shape of the VRs space with high dimensional accuracy. No differences in the prelecture test results were noted between the 3D printing group and the 2D image group. After the lecture, the knowledge of both groups improved, but the postlecture score and the change in the prelecture versus postlecture score were greater in the 3D printing group, and the subjective satisfaction survey feedback in the 3D printing group was also better (P < 0.05). Similar results were observed from the parental questionnaire, the vast majority of parents have an enthusiastic and positive attitude towards the use of 3D printed models and suggest using them in future prenatal consultations.ConclusionsThree-dimensional printing technology providing a new tool for effectively displaying different types of foetal VRs. This tool helps physicians and families understand the complex structure of foetal great vessels, positively impacting medical instruction and prenatal counselling.

Design of well-matched end-structure of anatomical proximal femoral locking plate based on computer-assisted imaging combined with 3D printing technology: a quality improvement study.

The extramedullary locking plate system was the common internal fixation method for hip fractures. However, common plates were poorly matched to femur, which was because they were designed based on anatomical parameters of the Western populations. Therefore, the aim was to design an end-structure of the anatomical proximal femoral locking plate that closely matched the anatomy of the Chinese population. From January 2010 to December 2021, consecutive patients aged 18 years and older who underwent a full-length computed tomography scan of the femur were included. The end-structure (male and female model) of the anatomical proximal femoral locking plate was designed based on anatomical parameters of femurs that were measured in three-dimensional space using computer-assisted virtual technology. The match degree between the end-structure and femur were evaluated. Inter-observer and intra-observer agreement for the evaluation of match degree was assessed. The matching evaluation based on a three-dimensional printing model was regarded as the gold standard to assess the reliability. A total of 1672 patients were included, with 701 men and 971 women. Significant differences were seen between male and female for all parameters of the proximal femur (all P <0.001). All match degree of end-structure was over 90%. Inter-observer and intra-observer agreement was almost perfect (all kappa value, >0.81). The sensitivity, specificity, and percentage of correct interpretation of matching evaluation in the computer-assisted virtual model was all greater than 95%. From femur reconstruction to completion of internal fixation matching, the process takes about 3min. Moreover, reconstruction, measurement, and matching were all completed in one system. The results showed that based on the larger sample of femoral anatomical parameters, a highly matching end-structure of anatomical proximal femoral locking plate for Chinese population could be designed with use of computer-assisted imaging technology.

Meta-analyzing the efficacy of 3D printed models in anatomy education.

Three-dimensional printing models (3DPs) have been widely used in medical anatomy training. However, the 3DPs evaluation results differ depending on such factors as the training objects, experimental design, organ parts, and test content. Thus, this systematic evaluation was carried out to better understand the role of 3DPs in different populations and different experimental designs. Controlled (CON) studies of 3DPs were retrieved from PubMed and Web of Science databases, where the participants were medical students or residents. The teaching content is the anatomical knowledge of human organs. One evaluation indicator is the mastery of anatomical knowledge after training, and the other is the satisfaction of participants with 3DPs. On the whole, the performance of the 3DPs group was higher than that of the CON group; however, there was no statistical difference in the resident subgroup, and there was no statistical difference for 3DPs vs. 3D visual imaging (3DI). In terms of satisfaction rate, the summary data showed that the difference between the 3DPs group (83.6%) vs. the CON group (69.6%) (binary variable) was not statistically significant, with p > 0.05. 3DPs has a positive effect on anatomy teaching, although there are no statistical differences in the performance tests of individual subgroups; participants generally had good evaluations and satisfaction with 3DPs. 3DPs still faces challenges in production cost, raw material source, authenticity, durability, etc. The future of 3D-printing-model-assisted anatomy teaching is worthy of expectation.

Towards Optimum Mandibular Reconstruction for Dental Occlusal Rehabilitation: From Preoperative Virtual Surgery to Autogenous Particulate Cancellous Bone and Marrow Graft with Custom-Made Titanium Mesh-A Retrospective Study.

The purpose of this retrospective study was to evaluate computer-assisted virtual surgery and the outcomes of mandibular reconstruction using an autogenous particulate cancellous bone and marrow (PCBM) graft combined with a custom-made titanium mesh (TiMesh) using a three-dimensional (3D) printing model. Eighteen consecutive patients were included, and preoperative virtual simulation surgery was performed using digital data. Segmental bone defects showed deviation of the mandible due to displacement of the condyle and segments, unnatural length of the mandibular body, or poorer intermaxillary relationship compared to the marginal bone defect caused by previous operations. These mandibular disharmonies could be simulated, and virtual surgery was performed on a computer with adjustment of displaced mandibular segments, length of the mandibular body, and dental arch with digital bone augmentation. TiMesh was manually pre-bent using a 3D printing model, and PCBM from the iliac crest was grafted with TiMesh. The short-term clinical results were good; reconstruction of the alveolar crest was prosthetically desirable; and minor complications were observed. In conclusion, virtual reconstruction is crucial for treating complex deviated mandibles. Accurate condylar and dental arch positions with an optimum mandibular length are important for prosthetically satisfactory mandibular reconstruction.

Enhanced Glutaminolysis Drives Hypoxia-Induced Chemoresistance in Pancreatic Cancer.

Increased glutaminolysis induces hypoxia via oxidative phosphorylation-mediated oxygen consumption and drives chemoresistance in pancreatic cancer, revealing a potential therapeutic strategy of combining glutaminolysis inhibition and chemotherapy to overcome resistance.

Three-Dimensional Printing Model Enhances Correct Identification and Understanding of Pelvic Fracture in Medical Students

Understanding the anatomy behind a pelvic fracture can be a significant challenge to medical students. Recent advances in three-dimensional printing technology offers a novel approach to facilitate the learning of complex fracture. We have described here how the 3-dimension printing (3Dp) models can help medical students improve their understanding in and identification of pelvic fractures. One hundred students were randomized into 2 teaching module groups (with or without 3Dp models). Prior to randomization assignment, a 50-minute didactic lecture covering elementary knowledge of anatomy, Young-Burgess classification, and traumatic mechanism of pelvic fracture was delivered to all students. The 3Dp group received X-rays, CT images, and 3Dp models of the eight pelvic fractures during presentation, while the students in the control group only obtained X-rays and CT scans of the same 8 pelvic fractures. Young-Burgess classification system and injury mechanism of pelvic fracture, time for evaluation, and subjective questions were conducted to assess the learning outcomes. A medical student program based in a LevelⅠtrauma center PARTICIPANTS: One hundred students in their 4th year of a 5-year clinical medicine program (for a medical bachelor degree) RESULTS: Students receiving 3Dp model had a higher rate of identifying the correct pelvic fracture via Young-Burgess identification compared to these without 3Dp model. Moreover, the accuracy of identifying the injury mechanism was significantly higher in the 3Dp group than that in group without 3Dp model. Participant in 3Dp group had faster assessment time compared to the control group. Subjective survey results suggested that 3Dp model would increase the learning interest and enhance the understanding of pelvic fracture. In addition, majority of students (83%) reported that they would like to use 3Dp model in other surgical course education. 3Dp model increased the perceived accuracy of pelvic fracture identification and understanding of injury mechanism. Moreover, 3Dp model promoted the subjective interest and motivation of students in pelvic fracture learning. Therefore, 3Dp model can be considered as a valuable educational tool for learning pelvic fracture in medical students.

The clinical performance of ultra-low-dose shoulder CT scans: The assessment on image and physical 3D printing models.

Evaluation of the clinical performance of ultra-low-dose computed tomography (CT) images of the shoulder joint on image-based diagnosis and three-dimensional (3D) printing surgical planning. A total of 93 patients with displaced shoulder fractures were randomly divided into standard-dose, low-dose, and ultra-low-dose groups. Three-dimensional printing models of all patients' shoulder joints were fabricated. The subjective image quality and 3D-printing model were evaluated by two senior orthopedic surgeons who were blinded to any scanning setting. A 3-point scale system was used to quantitatively assess the image quality and 3D printing model, where more than 2 points meant adequate level for clinical application. Compared with the standard dose protocol, ultra-low-dose technique reduced the radiation dose by 99.29% without loss of key image quality of fracture pattern. Regarding the subjective image quality, the assessment scores for groups of standard, low, and ultra-low doses were 3.00, 2.76, 2.00 points on scapula and humerus, and 3.00, 2.73, 2.44 points on clavicle. Scores of the three groups for the assessment of 3D printing models were 3.00, 2.80, 1.34 on scapula and humerus, and 3.00, 2.90, 2.06 on clavicle. In the ultra-low-dose group, 24 out of 33 (72.7%) 3D printing models of scapula and humerus received lower than 2 points of the evaluation score, while nearly 94% of the clavicle models reached the adequate level. An ultra-low-dose protocol is adequate for the diagnosis of either displaced or non-displaced fractures of the shoulder joint even though minor flaws of images are present. Three-dimensional printing models of shoulder joints created from ultra-low-dose CT scans can be used for surgical planning at specific bone like the clavicle but perform insufficiently in the overall surgical planning for shoulder injuries due to the significant geometric flaws.

Three-dimensional printing models improve long-term retention in medical education of pathoanatomy: A randomized controlled study.

Craniosynostosis is a rare and complex pathology, and visuospatial skills are necessary for a good understanding of the condition. While the use of three-dimensional (3D) models has improved the understanding of complex craniofacial anatomy, no study has evaluated the impact of this teaching support on long-term retention. Our randomized controlled trial was designed to compare the long-term retention of information with 3D-printed models of four types of craniosynostosis versus classic 3D reconstructions displayed in two-dimensional (2D) among undergraduate students. All students benefited from the same standardized course followed by the manipulation of the learning tool associated with the group for 15 min. Long-term retention was assessed by the capability to properly recognize different types of craniosynostosis 3 weeks after the course. Eighty-five students were enrolled. Previous educational achievements and baseline visuospatial skills were similar between the groups. The bivariate analysis showed the mean score in the 3D and 2D groups were 11.32 (2.89) and 8.08 (2.81), respectively (p < 0.0001). 3D-printed models of structures with spatial complexity such as various craniosynostosis patterns improve significantly medical students' long-term retention, indicating their educational efficacy.

Accuracy of the Application of 3-Dimensional Printing Models in Orbital Blowout Fractures-A Preliminary Study.

Application of 3-dimensional (3D) printing technology has grown in the medical field over the past 2 decades. In managing orbital blowout fractures, 3D printed models can be used as intraoperative navigators and could shorten the operational time by facilitating prebending or shaping of the mesh preoperatively. However, a comparison of the accuracy of computed tomography (CT) images and printed 3D models is lacking. This is a single-center retrospective study. Patients with unilateral orbital blowout fracture and signed up for customized 3D printing model were included. Reference points for the 2D distance were defined (intersupraorbital notch distance, transverse horizontal, sagittal vertical, and anteroposterior axes for orbital cavity) and measured directly on 3D printing models and on corresponding CT images. The difference and correlation analysis were conducted. In total, 9 patients were reviewed from June 2017 to December 2020. The mean difference in the intersupraorbital notch measurement between the 2 modules was -0.14 mm (P = 0.67). The mean difference in the distance measured from the modules in the horizontal, vertical, and anteroposterior axes of the traumatic orbits was 0.06 mm (P = 0.85), -0.23 mm (P = 0.47), and 0.51 mm (P = 0.32), whereas that of the unaffected orbits was 0.16 mm (P = 0.44), 0.34 mm (P = 0.24), and 0.1 mm (P = 0.88), respectively. Although 2D parameter differences (<1 mm) between 3D printing models and CT images were discovered, they were not statistically significant. Three-dimensional printing models showed high identity and correlation to CT image. Therefore, personalized models might be a reliable tool of virtual surgery or as a guide in realistic surgical scenarios for orbital blowout fractures.

Three-Dimensional Printing Model Enhances Craniofacial Trauma Teaching by Improving Morphologic and Biomechanical Understanding: A Randomized Controlled Study.

Teaching about craniofacial traumas is challenging given the complexity of the craniofacial anatomy and the necessity for good spatial representation skills. To solve these problems, three-dimensional printing seems to be an appropriate educative material. In this study, the authors conducted a randomized controlled trial. The authors' main objective was to compare the performance of the undergraduate medical students in an examination based on the teaching support: three-dimensionally printed models versus two-dimensional pictures. All participants were randomly assigned to one of two groups using a random number table: the three-dimensionally-printed support group (three-dimensional group) or the two-dimensionally-displayed support group (two-dimensional group). All participants completed a multiple-choice question evaluation questionnaire on facial traumatology (first, a zygomatic bone fracture; then, a double mandible fracture). Sex and potential confounding factors were evaluated. Four hundred thirty-two fifth-year undergraduate medical students were enrolled in this study. Two hundred six students were allocated to the three-dimensional group, and 226 were allocated to the two-dimensional group. The three-dimensionally printed model was considered to be a better teaching material compared with two-dimensional support. The global mean score was 2.36 in the three-dimensional group versus 1.99 in the two-dimensional group (p = 0.008). Regarding teaching of biomechanical aspects, three-dimensionally-printed models provide better understanding (p = 0.015). Participants in both groups exhibited similar previous student educational achievements and visuospatial skills. This prospective, randomized, controlled educational trial demonstrated that incorporation of three-dimensionally-printed models improves medical students' understanding. This trial reinforces previous studies highlighting academic benefits in using three-dimensionally-printed models mostly in the field of understanding complex structures.

Repairing Facial Fractures with Interrupted Maxillary-mandibular Arches by Computer-assisted Reverse Planning Model Surgery.

Background:Management of comminuted facial fractures with maxillary-mandibular arch interruption is difficult, resulting in inadequate bone reduction and malocclusion. Traditionally, a good quality dental splint is helpful, but difficult to obtain in acute trauma. We apply a computer-assisted design and three-dimensional printing technology to improve splint fabrication and utilization, thus facilitating restoration of dental occlusion and facial fracture.Methods:We retrospectively reviewed patients who suffered from facial fractures with interruption of the maxillary-mandibular arches. We developed the “computer-assisted reverse planning and three-dimensional printing model surgery” algorithm and applied it in selected patients. An occlusal splint was created as a surgical guide to enhance the maxilla-mandibular unit repair by taking care of the bone reduction and occlusion. All included patients were followed up to assess the functional outcome and patients suitable for this method.Results:From Jan 2015 to Aug 2020, 10 patients (eight men and two women) with comminuted facial fractures were included. The average time of surgery was 9.2 days. The average follow-up time was 8.6 months. There was no patient who needed major revision to correct malocclusion or facial asymmetry.Conclusions:A computer-assisted design splint decreases intraoperative inaccuracies and difficulty in comminuted maxillo-mandibular fractures. It is a useful and reliable alternative. Collaboration with an experienced engineer and patient selection are indispensable in delivering successful outcomes. Patients who have more than three bone fragments in a single dental arch or more than four bone fragments in the entire maxillary-mandibular unit appear to be excellent candidates for this method.

Scaffold-free 3D printing for fabrication of biomimetic branched multinucleated cardiac tissue construct: A promising ex vivo model for in situ detection of drug-induced sodium ion channel responses

3D bioprinted cardiac constructs have the potential to develop into functional native tissue. Although bioengineered cardiac constructs can be a promising tool for evaluating cardiac responses, the intrinsic limitation in reproducing the well-defined structural and functional properties of native cardiac tissue within the generated substitute restricts their applications. Herein, for the first time, we have introduced a sophisticated scaffold-free de novo three-dimensional (3D) printing model (SFP) to regenerate biomimetic cardiac tissue with a multinucleated branched cellular structure similar to native tissue–like phenotypes. Furthermore, the formation of tight intracellular junctions expressing connexin 43 certifies the maturation of the fabricated structure. In addition, in situ measurement of the bioengineered cardiac construct's physiologic sodium ion channel responses to known cardiac drugs was successfully performed. Hence, the proposed methodology recapitulates a significant milestone in developing biomimetic cardiac tissue structure and functionality in vitro and could be applied for regenerative therapies, disease modeling, and drug screening.