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Background: Medical education related to bone fracture must address numerous challenges including complex anatomical characteristics, diverse injury mechanisms, fracture typing, and treatment modalities. Our newly developed 3D printed model comprises components that may be combined or split to simulate various anatomical features, fracture types, and treatment modalities. This study aims to analyze the teaching utility of the new 3D-printed model compared with the traditional solid model. Methods: This prospective study included 112 students randomly assigned to fracture-related education with a conventional model or the newly developed 3D-printed model. All students received 40 min of lecture, 20 min for femoral neck and 20 min for tibiofibular fractures, and a post-class quiz (10 min each) immediately followed. Scores on tests of fracture-related knowledge and user satisfaction were measured pre and post education for comparison. Results: The 3D printing group had an advantage in retention of anatomic knowledge, fracture typing and choice of treatment for the femoral neck fracture (P < 0.05). For the tibiofibular fracture the 3D printing group had an advantage in retention of anatomic knowledge and fracture complications (P < 0.05).Scores on the questionnaire survey also showed increased satisfaction in the 3D-printed model group(P < 0.05). Conclusions: The proposed 3D-printed model can enhance the teaching effect significantly and has potential for widespread use in medical student education. [ABSTRACT FROM AUTHOR]

Abstract Background The application of 3D printing technology in preoperative planning and treatment of these fractures has shown promise in improving surgical efficiency, trauma, and patient outcomes. This study aims to demonstrate the advantages of applying 3D printing technology to the treatment of proximal humeral fractures by comparing cases selected for 3D printing with a control group (conventional surgery group), in order to further promote the application of 3D technology in a broader range of trauma treatments. Methods This study conducted the clinical data of 51 patients with proximal humeral fractures. Inclusion criteria encompassed patients diagnosed with Neer II and III type proximal humerus fractures. Among them, 24 patients underwent traditional surgery, while 27 patients underwent surgery with 3D printing technology support. Intraoperative parameters, functional outcomes, radiographic results at 6 months, and pain scores were collected and analyzed. Results The 3D printing group demonstrated significantly reduced total surgery time compared to the traditional surgery group (P

Abstract Background Medical education related to bone fracture must address numerous challenges including complex anatomical characteristics, diverse injury mechanisms, fracture typing, and treatment modalities. Our newly developed 3D printed model comprises components that may be combined or split to simulate various anatomical features, fracture types, and treatment modalities. This study aims to analyze the teaching utility of the new 3D-printed model compared with the traditional solid model. Methods This prospective study included 112 students randomly assigned to fracture-related education with a conventional model or the newly developed 3D-printed model. All students received 40 min of lecture, 20 min for femoral neck and 20 min for tibiofibular fractures, and a post-class quiz (10 min each) immediately followed. Scores on tests of fracture-related knowledge and user satisfaction were measured pre and post education for comparison. Results The 3D printing group had an advantage in retention of anatomic knowledge, fracture typing and choice of treatment for the femoral neck fracture (P

Objectives: The aim of this review was to analyze mechanical and biological properties of resin materials used with subtractive or additive techniques for oral appliances fabrication and compare them to those conventionally manufactured. Materials and methods: The protocol was registered online at Open Science Framework (OSF) registries () and the study was based on the preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P). An electronic search was conducted on MEDLINE (via PubMed), Scopus, and Web of Science from 1 February 2022 to 1 May 2022. Inclusion criteria: in vitro and in vivo studies published in the last 10 years, with CAD-CAM or 3D printed resins for occlusal splints. Data considered homogenous were subjected to meta-analysis (95% confidence interval [CI]; α = 0.05) with Stata17 statistical software. Since all variables were continuous, the Hedge g measure was calculated. A fixed-effects model was used for I2 = 0%, while statistical analysis was conducted using a random-effects model with I2 > 0%. Results: 13 studies were included after full-text reading. The mechanical properties most studied were wear, flexural strength, surface hardness and surface roughness, while only 1 study investigated biological properties, performing the XTT viability assay. For the meta-analysis, only surface roughness, volume loss, and flexural strength were selected. Considering surface roughness, the subtractive specimen had a lower average value compared to traditional ones (Hedge’s g with 95% CI = -1.25[ -1.84, − 0.66]). No significant difference was detected in terms of volume loss (P > 0.05) between the groups (Hedge’s g with 95% CI = -0.01 [-2.71, − 2.68]). While flexural strength was higher in the control group (Hedge’s g with 95% CI = 2.32 [0.10–4.53]). Conclusion: 3D printed materials showed properties comparable to conventional resins, while milled splint materials have not shown better mechanical performance compared with conventional heat-cured acrylic resin. Polyetheretherketone (PEEK) have great potential and needs to be further investigated. Biological tests on oral cell populations are needed to confirm the long-term biocompatibility of these materials. Clinical relevance: The use of “mixed splints” combining different materials needs to be improved and evaluated in future research to take full advantage of different characteristics and properties. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the influence of three angles (0°, 45°, and 90°) on the mechanical properties and surface characteristics of the specimens produced by a 3D printer and resin for provisional restorations. Material and Methods: In this in vitro study, ten bars (4 × 2 × 10 mm) were produced for each experimental group (n = 10), designed in the Meshmixer software and printed on a 3D printer. The bars were tested immediately, without aging. They were subjected to a three-point bending test in a universal testing machine, and the surface roughness was measured by a contact profilometer. Microhardness was measured by a microhardness tester and the surface roughness of the specimens was evaluated with a scanning electron microscope. Results: The flexural strength of the 0° group (236.20 ± 29.73) was significantly higher than those of the 45° (155.80 ± 36.19) and 90° (138.70 ± 48.20) groups. Similarly, the surface roughness of the 0° group (0.10 ± 0.06) was significantly lower than the 45° (1.62 ± 0.55) and 90° (0.97 ± 0.22) groups. Microhardness was similar among the groups. Conclusion: The 0° angulation, with deposition of the layers on the printed object so that they are oriented perpendicular to the direction of application of forces, resulted in the best resistance to bending and lower roughness, which may contribute to better clinical behavior.

Intrauterine adhesion (IUA) often leads to amenorrhea, infertility, and recurrent miscarriage, seriously affecting the physical and mental health of women. Clinically, surgical separation is the main treatment for IUA, but this approach frequently results in postoperative recurrence and has poor treatment efficacy. 3D bioprinted scaffolds have emerged as a cutting-edge approach in the treatment of IUA, capable of separating damaged areas to prevent adhesion formation and undergoing controllable in vivo degradation without the need for surgical removal. These scaffolds can be used for drug loading, stem cell transplantation, and exosome delivery, enabling the release of drugs or growth factors to the injured area to promote tissue repair and regeneration. Transplanting 3D bioprinted hydrogels loaded with stem cells or stem cell-derived exosomes to the damaged area can effectively promote the repair of IUA and improve pregnancy rates. 3D bioprinting can provide personalized treatment plans for patients, and the combined treatment strategy with stem cells or stem cell-derived exosomes holds promise as a powerful tool for treating IUA. [ABSTRACT FROM AUTHOR]

Purpose: The use of 3D-printing in every field of medicine is expanding, notably as an educational tool. The aim of this study was to assess how visuospatial abilities (VSA) of students may impact learning helped with 3D-printed models. Methods: Participants were undergraduate medical school students during their clinical rotation in oral and maxillofacial surgery in two French Universities. Students were included prospectively and consecutively from September 2021 to June 2023. First, a lecture about craniosynostosis was performed with the help of 3D-printed models of craniosynostotic skulls. Then, a mental rotation test (MRT) followed by a multiple-choice questions (MCQs) form about craniosynostosis presentations were submitted to the students. Results: Forty undergraduate students were finally included. Median MRT score was 15 (10.75;21) and median score to the MCQs was 13 (11.75;14). There was a significantly weak correlation between the MRT-A score and the score to the MCQs (rs = 0.364; p = 0.022). A simple linear regression was calculated to predict the result to the MCQs on MRT-A score [ (F(1,39) = 281.248; p < 0.0001), with a R2 of 0.878 ]. Conclusion: This study showed that VSA has an impact on the recognition of complex clinical presentations, i.e. skulls with craniosynostosis. The correlation found between VSA and complex 3D shape recognition after learning aided with 3D-printed model is emphasizing the importance of VSA when using innovative technologies. Thus, VSA training should be envisioned during the curriculum. [ABSTRACT FROM AUTHOR]

ABSTRACT Purpose: To evaluate the impact of simulators on the training of urology residents in retrograde intrarenal surgery (RIRS). Methods: The study involved training eight urology residents, using two artificial simulators; one developed by the Universidade Estadual do Pará, using three-dimensional printing technology, and the other one patented by the medical equipment manufacturer Boston Scientific The qualification of residents took place through a training course, consisting of an adaptation phase (S0), followed by three training sessions, with weekly breaks between them (S1, S2 and S3). Study members should carry out a RIRS in a standardized way, with step-by-step supervision by the evaluator using a checklist. The participants’ individual performance was verified through a theoretical assessment, before and after training (pre- and post-training), as well as by the score achieved in each session on a scale called global psychomotor skill score. In S3, residents performed an analysis of the performance and quality of the simulation, by completing the scale of student satisfaction and self confidence in learning (SSSCL). Results: At the end of the course, everyone was able to perform the procedure in accordance with the standard. The training provided a learning gain and a considerable improvement in skills and competencies in RIRS, with p < 0.05. SSSCL demonstrated positive feedback, with an overall approval rating of 96%. Conclusions: Artificial simulators proved to be excellent auxiliary tools in the training of urology residents in RIRS.

ABSTRACT Purpose: To develop and assess three-dimensional models of physeal fractures in dog femurs (3D MPFDF) using radiographic imaging. Methods: The study was conducted in three phases: development of 3D MPFDF; radiographic examination of the 3D MPFDF; and comparative analysis of the anatomical and radiographic features of the 3D MPFDF. Results: The base model and the 3D MPFDF achieved high fidelity in replicating the bone structures, accurately maintaining the morphological characteristics and dimensions such as length, width, and thickness, closely resembling natural bone. The radiographs of the 3D MPFDF displayed distinct radiopaque and radiolucent areas, enabling clear visualization of the various anatomical structures of the femur. However, in these radiographs, it was challenging to distinguish between the cortical and medullary regions due to the use of 99% internal padding in the printing process. Despite this limitation, the radiographs successfully demonstrated the representation of the Salter-Harris classification. Conclusions: This paper presents a pioneering project focused on technological advancement aimed at developing a method for the rapid and cost-effective production of three-printed models and radiographs of physeal fractures in dogs.

Abstract Computer-aided manufacturing (CAM) technology allows the use of different manufacturing techniques. This in vitro study aimed to evaluate the marginal fit of temporary restorations manufactured using conventional chairside methods, milling, and three-dimensional printing. Fifteen 3-element temporary restorations specimens were produced and categorized into three groups: non-digital, obtained using the conventional chairside method (GC); milled (GM); and three-dimensionally printed (GP). Marginal fit was assessed using scanning electron microscopy (SEM) performed under two conditions: one with only the central screw tightened, and the other with all three screws tightened. Horizontal misfit values were categorized as over-, equal-, and under-extended and qualitatively analyzed. Statistical analysis was performed using the Tukey–Kramer test (α=0.05). In the vertical assessment, three-dimensionally printed restorations demonstrated greater misfit than restorations obtained by milling and the conventional chairside method (P

Background: Fabricating clear aligners by thermoforming three‐dimensional printed dental models requires a high degree of accuracy. It is unknown whether model thickness affects the accuracy when used to thermoform aligners. Purpose: This research utilizes three‐dimensional printed models made with differing wall thicknesses to determine its effect on their ability to withstand deformation during aligner fabrication. Methods: A total of 50 models of different wall thickness (10 each of 0.5, 1.0, 1.5, 2.0 mm, and solid) were printed using model resin (Model V2, Formlabs) on a low‐force stereolithography printer (Form 3B, Formlabs). Aligners were then fabricated using a thermal pressure forming machine (Biostar V, Great Lakes Dental Technologies) utilizing 25 s cycles to adapt 0.030″ acrylic sheets (Invisacryl, Great Lakes Dental Technologies), then removed from the models and sprayed with a contrast powder (Optispray, Dentsply Sirona) to aid in scanning with an intraoral scanner (CEREC Primescan, Dentsply Sirona). Each aligner's data was then compared to the original file used for printing with 3D comparison software (Geomagic Control X, 3D Systems). Results: The results show model thickness greater than or equal to 2.0 mm produced clinically acceptable results within the margin of error (0.3 mm). A total of 0.5 mm thickness failed to withstand thermal forming in 4 of the 10 trials. A total of 0.5 mm produced 27.56% of results in tolerance, 1.0 mm produced 75.66% of results in tolerance, 1.5 mm had 80.38% of results in tolerance, 86.82% of 2 mm models were in tolerance, and solid had 96.45% of results in tolerance. Conclusion: Hollow models of thicknesses 2.0 mm and solid models produced clinically acceptable aligners while utilizing less resin per unit compared to solid models, thus being more cost effective, time efficient and eco‐friendly. Therefore, a recommendation can be made to print hollow models with a shell thickness of greater than 2.0 mm for aligner fabrication. [ABSTRACT FROM AUTHOR]

ABSTRACT Introduction: 3-dimensional printing has enabled the development of unique and affordable additive manufacturing, including the prototyping and production of surgical forceps. Objective: demonstrate the development, 3D printing and mechanical-functional validation of a laparoscopic grasping forceps. Methods: the clamp was designed using a computer program and printed in 3 dimensions with polylactic acid (PLA) filament and added 5 screws for better leverage. Size and weight measurements were carried out, as well as mechanicalfunctional grip and rotation tests in the laboratory with a validated simulator. Results: Called “Easylap”, the clamp weighed 48 grams, measured 43cm and was printed in 8 pieces, taking an average of 12 hours to produce. It allowed the simulation of the functional characteristics of laparoscopic pressure forceps, in addition to the rotation and rack locking mechanism. However, its strength is reduced due to the material used. Conclusion: It is possible to develop plastic laparoscopic grasping forceps through 3-dimensional printing.

Objective: To assess the preliminary effectiveness of three-dimensional printed orthoses compared with conventionally custom-fabricated orthoses in persons with chronic hand conditions on performance of daily activities, hand function, quality of life, satisfaction, and production time and costs. Design: Interventional feasibility study. Subjects: Chronic hand orthotic users (n = 21). Methods: Participants received a new three-dimensional printed orthosis according to the same type as their current orthosis, which served as the control condition. Primary outcome was performance of daily activities (Patient-Reported Outcomes Measurement Information System–Upper Extremity; Michigan Hand Questionnaire). Secondary outcomes were hand function, quality of life, and satisfaction. Furthermore, production time and costs were recorded. Results: At 4 months’ follow-up, no significant differences were found between three-dimensional printed orthoses and participants’ existing conventional orthoses on activity performance, hand function, and quality of life. Satisfaction with the three-dimensional printed orthosis was significantly higher and the production time and costs for three-dimensional printed orthoses were significantly lower compared with conventional orthoses. The three-dimensional printed orthosis was preferred by 79% of the participants. Conclusions: This feasibility study in chronic hand conditions suggests that three-dimensional printed orthoses are similar to conventional orthoses in terms of activity performance, hand function, and quality of life. Satisfaction, and production time and costs favoured the three-dimensional printed hand orthoses.

Abstract Objective The interest in using 3D printing in the healthcare field has grown over the years, given its advantages and potential in the rapid manufacturing of personalized devices and implants with complex geometries. Thus, the aim of the present study was to compare the mechanical fixation behavior of a 3D-printed interference screw, produced by fused deposition modeling of polylactic acid (PLA) filament, with that of a titanium interference screw. Methods Eight deep flexor porcine tendons, approximately 8 mm wide and 9 cm long, were used as graft and fixed to a 40 pounds-per-cubic-foot (PCF) polyurethane block at each of its extremities. One group was fixed only with titanium interference screws (group 1) and the other only with 3D-printed PLA screws (BR 20 2021 018283-6 U2) (group 2). The tests were conducted using an EMIC DL 10000 electromechanical universal testing machine in axial traction mode. Results Group 1 (titanium) obtained peak force of 200 ± 7 N, with mean graft deformation of 8 ± 2 mm, and group 2 (PLA) obtained peak force of 300 ± 30 N, and mean graft deformation of 7 ± 3 mm. Both the titanium and PLA screws provided good graft fixation in the polyurethane block, with no slippage or apparent deformation. In all the samples, the test culminated in graft rupture, with around 20 mm of deformation in relation to the initial length. Conclusion The 3D-printed PLA screw provided good fixation, similar to that of its titanium counterpart, producing satisfactory and promising results.

Abstract Objective Due to the popularity of 3D technology, surgeons can create specific surgical guides and sterilize them in their institutions. The aim of the present study is to compare the efficacy of the autoclave and ethylene oxide (EO) sterilization methods for objects produced by 3D printing with polylactic acid (PLA) material. Methods Forty cubic-shaped objects were printed with PLA material. Twenty were solid and 20 were hollow (printed with little internal filling). Twenty objects (10 solid and 10 hollow) were sterilized in autoclave, forming Group 1. The others (10 solid and 10 hollow) were sterilized in EO, composing Group 2. After sterilization, they were stored and referred to culture. Hollow objects of both groups were broken during sowing, communicating the dead space with the culture medium. The results obtained were statistically analyzed (Fisher exact test and residue analysis). Results In group 1 (autoclave), there was bacterial growth in 50% of solid objects and in 30% of hollow objects. In group 2 (EO), growth occurred in 20% of hollow objects, with no bacterial growth in solid objects (100% of negative samples). The bacteria isolated in the positive cases was non-coagulase-producing Staphylococcus Gram positive. Conclusions Sterilization by both autoclave and EO was not effective for hollow printed objects. Solid objects sterilized by autoclave did not demonstrate 100% of negative samples and were not safe in the present assay. Complete absence of contamination occurred only with solid objects sterilized by EO, which is the combination recommended by the authors.

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.

Abstract Background Fabricating clear aligners by thermoforming three‐dimensional printed dental models requires a high degree of accuracy. It is unknown whether model thickness affects the accuracy when used to thermoform aligners. Purpose This research utilizes three‐dimensional printed models made with differing wall thicknesses to determine its effect on their ability to withstand deformation during aligner fabrication. Methods A total of 50 models of different wall thickness (10 each of 0.5, 1.0, 1.5, 2.0 mm, and solid) were printed using model resin (Model V2, Formlabs) on a low‐force stereolithography printer (Form 3B, Formlabs). Aligners were then fabricated using a thermal pressure forming machine (Biostar V, Great Lakes Dental Technologies) utilizing 25 s cycles to adapt 0.030″ acrylic sheets (Invisacryl, Great Lakes Dental Technologies), then removed from the models and sprayed with a contrast powder (Optispray, Dentsply Sirona) to aid in scanning with an intraoral scanner (CEREC Primescan, Dentsply Sirona). Each aligner's data was then compared to the original file used for printing with 3D comparison software (Geomagic Control X, 3D Systems). Results The results show model thickness greater than or equal to 2.0 mm produced clinically acceptable results within the margin of error (0.3 mm). A total of 0.5 mm thickness failed to withstand thermal forming in 4 of the 10 trials. A total of 0.5 mm produced 27.56% of results in tolerance, 1.0 mm produced 75.66% of results in tolerance, 1.5 mm had 80.38% of results in tolerance, 86.82% of 2 mm models were in tolerance, and solid had 96.45% of results in tolerance. Conclusion Hollow models of thicknesses 2.0 mm and solid models produced clinically acceptable aligners while utilizing less resin per unit compared to solid models, thus being more cost effective, time efficient and eco‐friendly. Therefore, a recommendation can be made to print hollow models with a shell thickness of greater than 2.0 mm for aligner fabrication.

Objective: To determine the effect of common beverages and accelerated aging on the colour stability of filled resins, which could potentially be used for fabrication of 3D‐printed orthodontic brackets. Materials and Methods: GR‐17.1 (shades A1, A2, and A3), and GR‐10 Guide resins (pro3dure medical, Eden Prairie, MN) were printed on an Asiga MAX UV printer into discs 2 mm thick, with a diameter of 10 mm, and then post‐print processed as per manufacturer's instructions. Discs were immersed in 5 mL of coffee, tea, red wine, or distilled water for 7 days. Another group was subjected to accelerated aging in accordance with ISO Standard 4892‐2. Ten samples were produced per resin, per treatment condition. Colour measurements were taken on the discs before and after treatment using a spectrophotometer against white and black reference tiles to assess colour and translucency differences with the CIEDE2000 colour difference formula. Results: While initial colour of the printed resin discs was acceptable, all resin groups underwent significant colour change during the experiment. Red wine and coffee produced the greatest colour and translucency change, followed by tea, with accelerated aging producing the least change in colour and translucency. Conclusion: The 3D‐printed resins tested underwent significant changes in colour and translucency following exposure to endogenous and exogenous sources of staining, which may affect their acceptability for fabrication of aesthetic orthodontic brackets. [ABSTRACT FROM AUTHOR]

Objectives: Three-dimensional (3D) printing has been increasingly used to create accurate patient-specific 3D-printed models from medical imaging data. We aimed to evaluate the utility of 3D-printed models in the localization and understanding of pancreatic cancer for surgeons before pancreatic surgery. Methods: Between March and September 2021, we prospectively enrolled 10 patients with suspected pancreatic cancer who were scheduled for surgery. We created an individualized 3D-printed model from preoperative CT images. Six surgeons (three staff and three residents) evaluated the CT images before and after the presentation of the 3D-printed model using a 7-item questionnaire (understanding of anatomy and pancreatic cancer [Q1–4], preoperative planning [Q5], and education for trainees or patients [Q6–7]) on a 5-point scale. Survey scores on Q1–5 before and after the presentation of the 3D-printed model were compared. Q6–7 assessed the 3D-printed model's effects on education compared to CT. Subgroup analysis was performed between staff and residents. Results: After the 3D-printed model presentation, survey scores improved in all five questions (before 3.90 vs. after 4.56, p < 0.001), with a mean improvement of 0.57‒0.93. Staff and resident scores improved after a 3D-printed model presentation (p < 0.05), except for Q4 in the resident group. The mean difference was higher among the staff than among the residents (staff: 0.50‒0.97 vs. residents: 0.27‒0.90). The scores of the 3D-printed model for education were high (trainees: 4.47 vs. patients: 4.60) compared to CT. Conclusion: The 3D-printed model of pancreatic cancer improved surgeons' understanding of individual patients' pancreatic cancer and surgical planning. Clinical relevance statement: The 3D-printed model of pancreatic cancer can be created using a preoperative CT image, which not only assists surgeons in surgical planning but also serves as a valuable educational resource for patients and students. Key Points: • A personalized 3D-printed pancreatic cancer model provides more intuitive information than CT, allowing surgeons to better visualize the tumor's location and relationship to neighboring organs. • In particular, the survey score was higher among staff who performed the surgery than among residents. • Individual patient pancreatic cancer models have the potential to be used for personalized patient education as well as resident education. [ABSTRACT FROM AUTHOR]

Abstract Background Three-dimensional (3D) printing is a novel innovation in the field of craniomaxillofacial surgery, however, a lack of evidence exists related to the comparison of the trueness of skull models fabricated using different technology-based printers belonging to different cost segments. Methods A study was performed to investigate the trueness of cone-beam computed tomography-derived skull models fabricated using different technology based on low-, medium-, and high-cost 3D printers. Following the segmentation of a patient’s skull, the model was printed by: (i) a low-cost fused filament fabrication printer; (ii) a medium-cost stereolithography printer; and (iii) a high-cost material jetting printer. The fabricated models were later scanned by industrial computed tomography and superimposed onto the original reference virtual model by applying surface-based registration. A part comparison color-coded analysis was conducted for assessing the difference between the reference and scanned models. A one-way analysis of variance (ANOVA) with Bonferroni correction was applied for statistical analysis. Results The model printed with the low-cost fused filament fabrication printer showed the highest mean absolute error ( $$1.33\pm 0.24 \text{mm}$$ 1.33 ± 0.24 mm ), whereas both medium-cost stereolithography-based and the high-cost material jetting models had an overall similar dimensional error of $$0.07\pm 0.03 \text{mm}$$ 0.07 ± 0.03 mm and $$0.07\pm 0.01 \text{mm}$$ 0.07 ± 0.01 mm , respectively. Overall, the models printed with medium- and high-cost printers showed a significantly ( $$p

ABSTRACT Purpose: To evaluate the gain of microsurgical skills and competencies by urology residents, using low-fidelity experimental models. Methods: The study involved the use of training boards, together with a low-fidelity microsurgery simulator, developed using a 3D printer. The model consists in two silicone tubes, coated with a resin, measuring 10 cm in length and with internal and external diameters of 0.5 and 1.5 mm. The support for the ducts is composed by a small box, developed with polylactic acid. The evaluation of the gain of skills and competencies in microsurgery occurred throughout a training course consisting of five training sessions. The first sessions (S1-S4) took place at weekly intervals and the last session (S5) was performed three months after S4. During sessions, were analyzed: the speed of performing microsurgical sutures in the pre and post-training and the performance of each resident through the Objective Structure Assessment of Technical Skill (OSATS) and Student Satisfaction Self-Confidence tools in Learning (SSSCL). Results: There was a decrease in the time needed to perform the anastomosis (p=0.0019), as well as a progressive increase in the score in the OSATS over during sessions S1 to S4. At S5, there was a slightly decrease in performance (p

Background: Three-dimensional (3D) printing is a novel innovation in the field of craniomaxillofacial surgery, however, a lack of evidence exists related to the comparison of the trueness of skull models fabricated using different technology-based printers belonging to different cost segments. Methods: A study was performed to investigate the trueness of cone-beam computed tomography-derived skull models fabricated using different technology based on low-, medium-, and high-cost 3D printers. Following the segmentation of a patient's skull, the model was printed by: (i) a low-cost fused filament fabrication printer; (ii) a medium-cost stereolithography printer; and (iii) a high-cost material jetting printer. The fabricated models were later scanned by industrial computed tomography and superimposed onto the original reference virtual model by applying surface-based registration. A part comparison color-coded analysis was conducted for assessing the difference between the reference and scanned models. A one-way analysis of variance (ANOVA) with Bonferroni correction was applied for statistical analysis. Results: The model printed with the low-cost fused filament fabrication printer showed the highest mean absolute error ( 1.33 ± 0.24 mm ), whereas both medium-cost stereolithography-based and the high-cost material jetting models had an overall similar dimensional error of 0.07 ± 0.03 mm and 0.07 ± 0.01 mm , respectively. Overall, the models printed with medium- and high-cost printers showed a significantly ( p < 0.01 ) lower error compared to the low-cost printer. Conclusions: Both stereolithography and material jetting based printers, belonging to the medium- and high-cost market segment, were able to replicate the skeletal anatomy with optimal trueness, which might be suitable for patient-specific treatment planning tasks in craniomaxillofacial surgery. In contrast, the low-cost fused filament fabrication printer could serve as a cost-effective alternative for anatomical education, and/or patient communication. [ABSTRACT FROM AUTHOR]

Brachytherapy is an essential part of radical radiotherapy of cervical cancer. However, traditional brachytherapy applicators are difficult to be placed, cannot be adapted to individualized local lesions, and have unsatisfactory dose distribution for some patients with recurrent postoperative stumps or eccentric or large cervical cancer, which then affects the efficacy and prognosis. Personalized radiotherapy products can be designed for each patient by utilizing 3D printing technology. Combination of 3D printing technology and brachytherapy can effectively improve accuracy of radiotherapy. The application of 3D printing technology in cervical cancer brachytherapy mainly includes the construction of cervical cancer model to preoperative planning and display tumor shape as well as anatomic relationship between tumor and surrounding tissues. It also includes the production of personalized applicator to reduce the occurrence of air gaps to achieve precise dose distribution. In addition, the design of parallel/oblique needle channel applicator and the optimization of needle channel and target dose distribution are also included. Applications of 3D printing technology in brachytherapy of cervical cancer have been summarized in the afore-mentioned areas. At the same time, the challenges in the development of 3D printing materials, system establishment and image guidance have been discussed. [ABSTRACT FROM AUTHOR]

ABSTRACT Purpose: This study compared, through biomechanical evaluation under ventral flexion load, four surgical techniques for ventral stabilization of the atlantoaxial joint in dogs. Methods: In total, 28 identical atlantoaxial joint models were created by digital printing from computed tomography images of a dog, and the specimens were divided into four groups of seven. In each group, a different technique for ventral stabilization of the atlantoaxial joint was performed: transarticular lag screws, polyaxial screws, multiple screws and bone cement (polymethylmethacrylate–PMMA), and atlantoaxial plate. After the stabilization technique, biomechanical evaluation was performed under ventral flexion load, both with a predefined constant load and with a gradually increasing load until stabilization failure. Results: All specimens, regardless of stabilization technique, were able to support the predefined load without failing. However, the PMMA method provided significant more rigidity (p ≤ 0.05) and also best resisted the gradual increase in load, supporting a significantly higher maximum force (p ≤ 0.05). There was no statistical difference in flexural strength between the transarticular lag screws and plate groups. The polyaxial screws method was significantly less resistant to loading (p ≤ 0.05) than the other groups. Conclusions: The PMMA technique had biomechanical advantages in ventral atlantoaxial stabilization over the other evaluated methods.

Abstract The formation of biofilm on denture bases is a recurrent clinical problem that favors the development of denture stomatitis. The effectiveness of a hygiene protocol in a 3D-printed denture base resin is still uncertain. Objective To evaluate of the effectiveness of immersion, associated or not with brushing in a soap solution, on the biofilm control of a 3D-printed denture base resin. Methodology Specimens of denture base resins [Cosmos Denture (COS) and Classico (CLA/control)] were contaminated in vitro with Candida albicans and immersed in sodium hypochlorite 0.25% (SH, alkaline peroxide) AP, chlorhexidine digluconate 2% (CD or PBS-Control), associated or not with brushing with 0.78% Lifebuoy soap. Roughness was evaluated before and after brushing and immersion. The effectiveness of the protocols was assessed by CFU/mL, cellular metabolism (XTT), scanning electron microscopy (SEM), and confocal scanning laser microscopy. Data were analyzed by T student, ANOVA/Welch, and Tukey/Gomes–Howell pos-hoc tests (α = 0.05). Results CLA showed greater roughness than COS. CFU/mL and XTT were higher in COS resin with a higher hyphae formation. Immersion in SH and CD eliminated CFU/mL and reduced XTT for both resins, associated or not with brushing. AP reduced CFU/mL only when associated with brushing. Conclusions The biofilm on the 3D-printed resin was thicker and presumably more pathogenic, regardless of its smoother surface. Immersions in SH 0.25% and CD 2% are effective hygiene protocols for both resins, associated or not with brushing. AP should be recommended when associated with brushing with a Lifebuoy 0.78% solution.

Flapless and fully guided implant placement has the potential to maximize efficacy outcomes and at the same time to minimize surgical invasiveness. The aim of the current systematic review was to answer the following PICO question: "In adult human subjects undergoing dental implant placement (P), is minimally invasive flapless computer‐aided fully guided (either dynamic or static computer‐aided implant placement (sCAIP)) (I) superior to flapped conventional (free‐handed implant placement (FHIP) or cast‐based/drill partially guided implant placement (dPGIP)) surgery (C), in terms of efficacy, patient morbidity, long‐term prognosis, and costs (O)?" Randomized clinical trials (RCTs) fulfilling specific inclusion criteria established to answer the PICO question were included. Two review authors independently searched for eligible studies, screened the titles and abstracts, performed full‐text analysis, extracted the data from the published reports, and performed the risk of bias assessment. In cases of disagreement, a third review author took the final decision during ad hoc consensus meetings. The study results were summarized using random effects meta‐analyses, which were based (wherever possible) on individual patient data (IPD). A total of 10 manuscripts reporting on five RCTs, involving a total of 124 participants and 449 implants, and comparing flapless sCAIP with flapped FHIP/cast‐based partially guided implant placement (cPGIP), were included. There was no RCT analyzing flapless dynamic computer‐aided implant placement (dCAIP) or flapped dPGIP. Intergroup meta‐analyses indicated less depth deviation (difference in means (MD) = −0.28 mm; 95% confidence interval (CI): −0.59 to 0.03; moderate certainty), angular deviation (MD = −3.88 degrees; 95% CI: −7.00 to −0.77; high certainty), coronal (MD = −0.6 mm; 95% CI: −1.21 to 0.01; low certainty) and apical (MD = −0.75 mm; 95% CI: −1.43 to −0.07; moderate certainty) three‐dimensional bodily deviations, postoperative pain (MD = −17.09 mm on the visual analogue scale (VAS); 95% CI: −33.38 to −0.80; low certainty), postoperative swelling (MD = −6.59 mm on the VAS; 95% CI: −19.03 to 5.85; very low certainty), intraoperative discomfort (MD = −9.36 mm on the VAS; 95% CI: −17.10 to −1.61) and surgery duration (MD = −24.28 minutes; 95% CI: −28.62 to −19.95) in flapless sCAIP than in flapped FHIP/cPGIP. Despite being more accurate than flapped FHIP/cPGIP, flapless sCAIP still resulted in deviations with respect to the planned position (intragroup meta‐analytic means: 0.76 mm in depth, 2.57 degrees in angular, 1.43 mm in coronal, and 1.68 in apical three‐dimensional bodily position). Moreover, flapless sCAIP presented a 12% group‐specific intraoperative complication rate, resulting in an inability to place the implant with this protocol in 7% of cases. Evidence regarding more clinically relevant outcomes of efficacy (implant survival and success, prosthetically and biologically correct positioning), long‐term prognosis, and costs, is currently scarce. When the objective is to guarantee minimal invasiveness at implant placement, clinicians could consider the use of flapless sCAIP. A proper case selection and consideration of a safety margin are, however, suggested. [ABSTRACT FROM AUTHOR]

Abstract Accurate and reproducible analysis of murine small and large intestinal tissue is key for preclinical models involving intestinal pathology. Currently, there is no easily accessible, standardized method that allows researchers of different skill levels to consistently dissect intestines in a time‐efficient manner. Here, we describe the design and use of the 3D‐printed “Mouse Intestinal Slicing Tool” (MIST), which can be used to longitudinally dissect murine intestines for further analysis. We benchmarked the MIST against a commonly used procedure involving scissors to make a longitudinal cut along the intestines. Use of the MIST halved the time per mouse to prepare the intestines and outperformed alternative methods in smoothness of the cutting edge and overall reproducibility. By sharing the plans for printing the MIST, we hope to contribute a uniformly applicable method for saving time and increasing consistency in studies of the mouse gastrointestinal tract.

In nature, basically 2 types of myocardial vascular patterns exist: the sinusoidal and the coronary type. In the sinusoidal type, the sinusoid is completely fed by blood coming directly from the ventricle through a spongy sinusoidal network. This pattern is found in cold-blooded animals and in the early embryologic development of human (warm-blooded) hearts. A 61-year-old man with atrial fibrillation developed severe tachymyopathy with a severely reduced left-ventricular ejection fraction (LVEF) of 20%. The patient had no history of prior heart surgery or other cardiac interventions. He was referred for a computed tomography (CT) scan for assessment of pulmonary vein anatomy prior to their isolation. Incidentally, a focal myocardial defect of the midventricular infero-septal wall with tail-like extension into the right ventricular cavity was detected. In a cardiac magnetic resonance (CMR) scan there was no evidence of a myocardial infarction or fibrosis. In the absence of a ventricular septal defect by CT, CMR and echocardiography the diagnosis of a persistent myocardial sinusoid was evident. In this case, we used state-of-the art methods for pathology visualization, illustrating the effectiveness of CT and CMR in the precise detection and differential diagnosis of myocardial anomalies including a multi-coloured 3D-printed model that may further enhance visuospatial appreciation of those anomalies.

The aim of this study was to develop a composite thermosensitive hydrogel for bone regeneration applications. This hydrogel consisted of chitosan, alginate and hydroxyapatite, and was loaded with zoledronic acid as a model drug. The feasibility of three-dimensional (3D) printing of the thermosensitive hydrogel using the extrusion based technique was investigated. The 3D printing technique called Freeform Reversible Embedded Suspended Hydrogel (FRESH) printing was employed for this purpose. To characterize the composite hydrogels, several tests were conducted. The gelation time, rheological properties, and in vitro drug release were analyzed. Additionally, the cell viability test on human osteosarcoma MG-63 cells for the composite hydrogel was assessed using an MTT assay. The results of the study showed that the zoledronic acid-loaded composite thermosensitive hydrogel was successfully printed using the FRESH 3D printing technique which was not possible otherwise i.e., by using traditional 3D printing techniques. Further examination of the printed constructs using a Scanning Electron Microscope revealed the presence of porous and layered structures. The gelation times of the composite thermosensitive hydrogel was determined to be 10 and 20 min, respectively for scaffolds with and without HA, indicating the successful formation of the gel within a reasonable time to the FRESH technique. The flow behavior of the hydrogel was found to be pseudoplastic, following a non-Newtonian flow pattern with Farrow's constant (N) values of 1.708 and 1.853 for scaffolds with and without hydroxyapatite, respectively. In terms of drug release, scaffolds prepared with and without hydroxyapatite reached nearly 100% of zoledronic acid release in 360 h and 48 h, respectively. The cell viability test on human osteosarcoma MG-63 cells using MTT assay has shown increased cell viability % in the case of composite hydrogel, indicating biocompatibility of the scaffold. Overall, this study successfully developed a composite thermosensitive hydrogel loaded with zoledronic acid for bone regeneration applications and was 3D printed using the FRESH 3D printing technique. The results of this study provide valuable insights into the potential use of this composite hydrogel for future biomedical applications., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: M.M., an author of this manuscript, holds stock in, serves on a scientific advisory board for, or is a consultant for CoM3D Ltd. (Surrey, UK), DosePlus Therapeutics, Inc. (Princeton, NJ, USA), and Septum Solutions LLC (Houston, TX, USA). The terms of this arrangement have been reviewed and approved by the University of Texas at Austin and the University of Mississippi (Ole Miss) in accordance with their policies on objectivity in research. The companies had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; and in the decision to publish the results., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This research focuses on exploring the solid solubility and miscibility of Etoricoxib, a poorly water-soluble anti-inflammatory drug, within Soluplus®, a polymer used as a matrix for 3D-printed tablets. By utilizing hot-melt extrusion (HME), the drug was dispersed within Soluplus® to enhance its solubility. The extrudates were then employed in 3D printing to create customized solid oral dosage form. This study's novelty lies in combining HME and 3D printing, aiming to improve drug incorporation, stability, and effectiveness in the final formulation. Comprehensive characterization techniques, including hot stage microscopy (HSM), scanning electron microscopy (SEM), micro-computed tomography (Micro-CT), florescence microscopy, optical microscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), solubility studies, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and aqueous solubility study were utilized to elucidate the physicochemical properties, thermal stability, and structural integrity for the extruded filaments (the printing ink), and 3D printed tablets made thereof. Furthermore, the in vitro drug release profile of the 3D printed tablet was systematically evaluated, revealing a controlled drug release pattern from the finished dosage form. The systematic investigation reported herein, starting from theoretical miscibility to the printing ink development through HME, detailed characterization of the extruded filaments, and further solid oral formulation development by additive manufacturing can be utilized as a platform technology or a pathway for the development of personalized medicine with drugs having similar physicochemical properties., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Anatomical 3D-printed nasal casts are valuable models to investigate intranasal drug deposition, providing preclinical data that cannot be obtained in animal models. However, these models are limited since they are often derived from a single patient or represent a mean of several groups. The present study aimed to better characterize the anatomical differences of the nasal cavity in a European sub-population and to assess the potential impact of anatomical variations on intranasal deposition by medical devices. Ninety-eight cranial computed tomography scans of patients were selected and analyzed in 2D and 3D conformations. They showed symmetry of cavities and a high level of heterogeneity of measurements, especially volume and area, in the population. Three anatomical groups with distinct nasal geometry were identified and 3D nasal casts of the most representative patient of each group were printed. Fluorescein was administered using three medical devices: a nasal spray, a sonic jet nebulizer and a prototype mesh-nebulizer. The deposition profiles were compared with the Aeronose® as a reference. Our results show that anatomical variations influenced the deposition profiles depending on the device, with a higher variation with spray and the mesh-nebulizer. This work emphasises the importance of anatomical parameters on drug intranasal deposition and the need to evaluate inhaled drugs on different 3D nasal casts reflecting the target population., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: HERVE VIRGINIE reports financial support was provided by Research Center for Respiratory Diseases − Inserm U1100. LE GUELLEC SANDRINE reports a relationship with DTF medical that includes: employment. In the past 3 years, NHV and her group received research supports and subcontracting fees from medical device companies, including Aerogen and DTF medical outside the scope of the present study and from Aptar Pharma and Nemera on the development of nasal models. The Aeronose® model belong to equally to APTAR PHARMA/University of Tours – CEPR Inserm U1100/DTFmedical. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Herein, we demonstrate for the first time the feasibility of employing significant amounts (up to 80 wt%) of unexplored industrial wastes (red mud and biomass fly ash) in the production of highly porous 3D-printed geopolymer lattices envisioned for wastewater treatment applications. This without compromising the mechanical performance of the geopolymers relative to those obtained using commercial precursors. The impact of the fly ash incorporation content in the fresh-state (calorimetric and reological characterization) and hardened-state (porosity and mechanical strength) properties of the produced structures was evaluated. Moreover, the influence of key printing parameters, including nozzle diameter and geometry alignment, on the resulting properties of the lattices was also evaluated. The most promising compositions were then evaluated as lead sorbents under continuous flow. The waste-based 3D-printed lattices showed remarkable adsorption ability reaching >95 % removal efficiency after 2 h. This sustainable strategy is in line with the United Nations sustainable development goals and the transition to a circular economy, reducing the consumption of natural resources and simultaneously contributing to reducing water pollution., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Rational regulation of pH and xanthan gum (XG) concentration has the potential to modulate interactions among macromolecules and enhance 3D printability. This study investigated non-covalent interactions between XG and other components within compound proteins emulsion gel systems across varying pH values (4.0-8.0) and XG concentrations (0-1 wt%) and systematically explored impacts of gelation properties and structural features on 3D printability. The results of rheological and structural features indicated that pH-regulated non-covalent interactions were crucial for maintaining structural stability of emulsion gels with the addition of XG. The 3D printability of emulsion gels would be significantly improved through moderate depletion flocculation produced when XG concentration was 0.75 wt% at the pH 6.0. Mechanical properties like viscosity exhibited a strongly negative correlation with 3D printability, whereas structural stability showed a significantly positive correlation. Overall, this study provided theoretical insights for the development of emulsion gels for 3D printing by regulating non-covalent interactions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

The combination of biocompatible materials and advanced three-dimensional (3D) additive manufacturing technologies holds great potential in the development of finely tuned complex scaffolds with reproducible macro- and micro-structural characteristics for biomedical applications, such as tissue engineering and drug delivery. In this study, biocompatible printable inks based on chitosan, collagen and gelatin were developed and 3D-printed with a pneumatic-based extrusion printer. The printability of various chitosan-gelatin (CS-Gel) hydrogel inks was assessed by evaluating the quality of the printed constructs. The inks required an extrusion pressure of 150 ± 40 MPa with G22 and G25 nozzles for optimal printing. Inks with low chitosan concentrations (<4% w/v) exhibited poor printability, while inks with 4 % w/v chitosan and 1 % w/v gelatin (CG) demonstrated satisfactory extrusion and printing quality. The addition of collagen (0.1 % w/v) to the optimized ink (CGC) did not compromise printability. Post-printing stabilization using KOH produced self-supporting scaffolds with consistent morphological integrity, while weaker bases like NaOH/EtOH and ammonia vapors resulted in lower pore sizes and reduced structural stability. Water evaporation studies showed that neutralized samples had slower evaporation rates due to the strong intermolecular interactions formed during the neutralization process, contributing to a stable crosslinked network. FTIR spectra confirmed the formation of polyelectrolyte complexes in the CS-Gel and CS-Gel-Collagen blends, further enhancing structural stability. Swelling tests indicated that neutralized constructs maintained stability in different pH environments, with KOH-treated samples exhibiting the lowest swelling ratios and the highest structural stability. After optimizing the ink composition, 10 wt% Levofloxacin was loaded in the constructs as a model antibiotic and it's in vitro release rate was quantified. Drug loading was approximately 4 % for both ink compositions GC and CGC. CG Levo released over 80 % of levofloxacin within the first hour, reaching full release in 24 h, indicating inadequate control, while CGK Levo exhibited slower initial release (55 % in 15 min) followed by stabilized release after 4 h, likely due to controlled diffusion from expanded constructs. These findings demonstrate that the developed hydrogel inks and optimized printing parameters can produce scaffolds suitable for tissue engineering applications. Finally, the cell compatibility of the 3D-printed constructs was confirmed with MTT assay on fibroblasts and the antimicrobial activity of the drug-loaded constructs was tested against E. coli and S. aureus, showing an increase of the bacteria free zone from 8 ± 0.4 mm of the control against E. coli up to 16.4 ± 0.37 mm in the presence of the KOH-treated CG Levo printed construct., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Although soluble bio-accelerators have proven effective in mitigating Cr(VI) inhibition within denitrification system, issues persist in immobilizing bio-accelerators and making them slow-release for sustained regulation. In this study, a novel strategy was proposed to fabricate immobilized bio-accelerators with controlled structure, sustained release property by 3D printing technology. Notably, the sustained release of bio-accelerators from 3D-printed bio-accelerators (3DP-B) lasted for at least 144 h. Compared to control group, 3DP-B with basic components (3DP-BB) shortened the recovery time by 1.4 folds, and the COD and NO 3 - -N removal efficiency was 36.5 % and 38.0 % higher than that of natural recovery. Correspondingly, the activity of key enzymes (nitrate reductase, nitrite reductase, nitric oxide reductase, and nitrous oxide reductase), electron transfer system activity and extracellular polymer substances of denitrification biofilm maintained at relatively high levels. Furthermore, introducing 60 mg·L -1 anthraquinone-2,6-disulfonate (AQDS) into the ink showed noticeable superiority on the bio-inhibition release over 1000 mg·L -1 AQDS. The released AQDS facilitated the electron transport capacity by 1.25 times compared with control group. The groundbreaking findings of this study could advance the development of 3D printing technology and utilization of bio-accelerators in the field of wastewater treatment., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

This Review explores the rapidly evolving field of bioengineered vasculature, a key area of focus in tissue engineering and regenerative medicine. The broad relevance of this topic is attributed to its impacts on a wide range of biological processes, enabling studies in tissue development, fundamental biology and drug discovery, and the applications in tissue engineering and regenerative medicine. We outline the design criteria for bioengineered vasculature and the methodologies for constructing these systems by self-assembly and in microfluidics, organs-on-a-chip and macroscale tubular systems that often rely on biofabrication approaches such as 3D printing. We discuss existing challenges in developing functional vasculature that closely mirrors its native equivalent, including achieving hierarchical branching with organ and vessel-specific endothelial and supporting cells, providing perusable vasculature within organoids and scaling the systems for implantation and direct vascular anastomosis., Competing Interests: Competing interests M.R. and Y.Z. are inventors on an issued US patent for Biowire technology that is licensed to Valo Health; they receive royalties for this invention., (© 2024. Published by The Company of Biologists Ltd.)

Pea protein isolate (PPI) is a valued sustainable protein source, but its relatively poor functional properties limit its applications. This study reports on the effects of cold argon plasma (CP) treatment of a 15 % (w/w) PPI solution on the functionality, structure, and oxidative characteristics of PPI, as well as its application in 3D-printed plant-based meat. Results indicate that hydroxyl radicals and high-energy excited-state argon atoms are the primary active substances. A decrease in free sulfhydryl content and an increase in carbonyl content were observed in treated PPI, indicating oxidative modification. Compared to the control group, the gel strength of PPI was increased by 62.5 % and the storage modulus was significantly improved after 6 min treatment, forming a more ordered and highly cross-linked 3D gel network. Additionally, CP significantly improved the water-holding capacity, oil-holding capacity, emulsifying activity, and emulsion stability of PPI. The α-helix and random coil content in PPI decreased, while the β-sheet content increased, resulting in a more ordered secondary structure after CP treatment. Compared to untreated PPI, the consistency coefficient (K) increased from 36.00 to 47.68 Pa·s n . The treated PPI exhibited higher apparent viscosity and storage modulus and demonstrated better 3D printing performance and self-supporting ability. This study demonstrates that CP can significantly enhance the functional properties of PPI, providing great potential and prospects for improving the printability of 3D printing materials and developing plant protein foods with low-allergenicity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objectives: This paper aims to explore the application value of mixed reality in oral and maxillofacial surgery and to conduct dynamic tracking using an in vitro model., Methods: By collecting preoperative enhanced CT data of patients, rebuilding 3D digital model, combined with 3D printing technology, dynamic tracking of lesions was realized in the in vitro model, and the efficiency of different registration methods was compared., Results: The 3D visualized head and neck model was obtained by combining multiple anatomical models, and dynamic tracking was completed in vitro . The average tracking time of the facial mark recognition method was T45°=3.67 frames, T90°=10.67 frames, and T total=12 seconds 28 frames (30 frames per second). The average tracking time of QR code recognition method was T45°=1.67 frames, T90°=2.33 frames, and T total=11 seconds 13 frames (30 frames per second)., Conclusions: The combination of MR technology and 3D printing technology can realize the dynamic tracking of lesions in vitro , which lays a foundation for the clinical application of MR technology to implement precise, personalized surgical programs.

Plant-based fat analogs are important alternatives to animal fats proposed in response to the strategy of low fat, low saturation, and sustainable development. Apart from possessing solid or semi-solid fat-analog structural properties, plant-based fat analogs also exhibit ideal rheological properties, making them highly suitable for food 3D printing. By utilizing 3D printing technology, it is feasible to personalize both the external (color and shape) and internal (nutrition and flavor) aspects of food, as well as plant-based fat analogs. Therefore, this review focuses on the research progress of plant-based fat analogs prepared based on 3D printing technology in the custom design of low-fat healthy food. This paper comprehensively reviews the latest advancements in manufacturing plant-based fat analogs from three perspectives: food hydrocolloids, oleogels, and emulsion gels. Then, starting with the printability of plant-based fat analogs, the food 3D printing technology and the printing characteristics of plant-based fat analogs are introduced. Next, strategies to adjust the printing stability of plant-based fat analogs to improve their plasticity and fidelity are discussed. Finally, the application prospects and limitations of plant-based fat analogs prepared by extrusion 3D printing technology in meat products, bakery goods, chocolates, and aerated food are discussed, which provides a reference for expanding the application of 3D printing in the field of fat-reducing and healthy food., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Summary: The increase in access to facial gender-affirming surgery has resulted in an increase in facial feminization procedures for transfeminine and gender nonbinary populations. However, refined execution of facial masculinization is challenged by the lack of defined measurements for facial augmentation, the lack of long-term predictability in autologous bone grafting in augmentation procedures, and the lack of precision in traditional facial augmentation procedures with generic alloplastic implants. The authors describe an innovation in facial masculinization surgery using modern reconstructive craniofacial surgical techniques with preoperative virtual modeling and the fabrication of 3-dimensionally printed, patient-specific custom implants., (Copyright © 2024 by the American Society of Plastic Surgeons.)

Iron deficiency anemia (IDA) is a prevalent and serious nutritional health issue that can be mitigated through dietary iron supplementation. However, only ferrous ions, prone to oxidation, can be absorbed in the gastrointestinal tract. In the current work, the effects of high internal phase Pickering emulsions (HIPPEs) co-loaded with astaxanthin (ASTA) and ferrous gluconate on Fe 2+ oxidation, IDA management, and their 3D printing performance were investigated. The results demonstrated that the HIPPEs co-loaded with ASTA and ferrous gluconate effectively reduced the oxidation rate of Fe 2+ during storage. Animal studies also revealed that HIPPE co-loaded with ASTA and ferrous gluconate had a therapeutic effect on IDA symptoms in mice. HIPPE co-loaded with ASTA and 400 mg/L ferrous gluconate demonstrated superior efficacy in restoring hemoglobin (Hb) levels, organ coefficients, and histological parameters in mice with IDA. Moreover, the evaluation of the adaptability of HIPPEs co-loaded with ASTA and ferrous gluconate for food 3D printing indicated a slight reduction in printing resolution. Overall printing performance was found to be acceptable and satisfactory. Co-loading ASTA and ferrous gluconate in HIPPEs offers an efficient way to address the oxidation challenge of ferrous ion supplementation, enabling customization and flexibility in the production of iron-fortified foods to mitigate IDA., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Severe infantile tracheobronchomalacia (TBM) is often treated with invasive surgery and fixed-size implants to support the trachea during respiration. A novel 3D-printed extra-luminal splint has been developed as a flexible and bioresorbable alternative. Therefore, the goal of the present study was to use an in vitro breathing simulator model to comprehensively evaluate the structural stiffness and failure modes of two sizes of a novel bioresorbable 3D-printed splint design under a range of physiological degradation conditions. Two thicknesses, 2 mm and 3 mm, of a novel 3D-printed bioresorbable splint were evaluated under two different degradation conditions, phosphate-buffered saline (PBS) and sodium hydroxide (NaOH). The splints were subjected to simulated breathing loading, involving a cyclic opening and closing of the splint by 2 mm, for a targeted duration of 7.5 to 30 million cycles. A separate new set of splints were statically soaked in their respective degradation condition for a comparative analysis of the effects of cyclic loading by the degradation medium. After successfully simulated breathing or static soaking, non-destructive tensile and compressive strengths were evaluated, and overall stiffness was calculated from destructive tensile testing. The present study indicates that the splints were more significantly degraded under simulated breathing conditions than under soaking. Cyclic simulated breathing specimens failed far earlier than the intended duration of loading. Over time, both 2 mm and 3 mm splints became increasingly more flexible when subjected to the static degradation conditions. Interestingly, there was little difference in the compressive and tensile strengths of the 2 mm and 3 mm thickness splints. The bioresorbable nature of PCL offers a valuable advantage as it eliminates the need for splint removal surgery and increases device flexibility over time with degradation. This increased flexibility is crucial because it allows for uninhibited growth and development of the infant's trachea over the intended use period of 2 years. The results of this study confirm that the splints were able to withstand tensile forces to prevent tracheal collapse. This study further supports the successful use of 3D-printed splints in the treatment of infantile TBM., (© 2024 The Author(s). Journal of Biomedical Materials Research Part B: Applied Biomaterials published by Wiley Periodicals LLC.)

3D printing ready-to-eat emulsions using trans-fat-free edible oil, presents a significant challenge due to the complexities involved in achieving the necessary material structure, rheological properties, and stability. This study fabricated High Internal Phase Emulsions (HIPEs) stabilized with citrus fibers and octenyl succinic anhydride (OSA) modified waxy starch, serving as the printable inks for 3D-printable elderly foods. These printable inks exhibited a pseudoplastic gel structure, which provided enhanced extrudability and improved shape retention. The incorporation of citrus fiber, water, OSA starch, sunflower oil at a concentration of 0.3 wt%, 22.7 % wt %, 2 % wt%, 75 wt% in the 3D-printed HIPEs resulted in optimal addition, yielding the highest level of shape accuracy. Compared to the addition of OSA-modified starch, microstructural analysis and rheological testing (using Lissajous-Bowditch plots) indicated that the addition of citrus fiber had a greater impact on the rheological and textural properties of the HIPEs, which improved shape retention and fluidity of the HIPEs, and ensure the stability of continuous extrusion printing. Additionally, bionic tribological properties demonstrated that tribological properties of the prepared HIPEs were very close to the ones of mayonnaise, which indicating that the prepared HIPEs had smooth texture and easy-to-chew properties for the elderly. These findings offered a comprehensive understanding of the structure-function relationship between the molecular structures of HIPEs and their 3D printability, providing technical insights for the development of 3D-printed emulsion-based ready-to-eat elderly food products. This study provided a good industrialized method for HIPEs stabilized with only fruit dietary fiber and modified starch, and facilitated the development of emulsion-based ready-to-eat food products with 3D printability., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: We present a method to determine and visualise the functional centre of rotation (FCOR) of the hip during total hip arthroplasty using an augmented reality head mounted display (AR-HMD)., Methods: We developed software allowing a HoloLens to provide inside-out infrared tracking of markers affixed to cadaver femurs and 3D printed acetabuli. Two observers rotated 20 cadaver femurs twice in a matching cup, producing 80 measurements. The FCOR of the acetabulum and femoral head was determined based on the point cloud generated from the displacement of the femoral trackers to the acetabular tracker., Results: Compared to the ground truth, the FCOR resulted in an absolute error of 2.9 ± 1.4 mm for the acetabulum and 2.9 ± 1.2 mm for the femur, with 95th percentiles below 5.6 and 4.7 mm., Conclusion: The proposed AR-HMD system offers an accurate and reproducible way to determine the femoral and acetabular FCOR in an experimental setting., (© 2024 The Author(s). The International Journal of Medical Robotics and Computer Assisted Surgery published by John Wiley & Sons Ltd.)

Introduction: Digital orthodontics is here to make our specialty more efficient, and the integration of artificial intelligence (AI) is no exception. This study aimed to compare the accuracy of a workflow involving virtual bracket removal (VBR) by AI to traditional bracket removal. A secondary objective was to compare the clinical fit of thermoplastic orthodontic retainers fabricated from 3-dimensional (3D) printed models created by each method., Methods: Thirty dental arches were scanned intraorally with the fixed labial orthodontic brackets in place, creating 30 standard tessellation language (STL) files which were labeled "pre-debond." For each patient, all brackets and residual adhesive were then clinically removed, and an additional intraoral scan was taken and labeled "post-debond." Each pre-debond scan was uploaded to the uDesign by uLab software (version 7.0; uLab Systems, Inc, Memphis, Tenn), which uses AI to virtually remove orthodontic brackets using 1-touch bracket identification. New STL files were created for each of the 30 arches and labeled VBR. Best fit superimpositions were performed using Geomagic Control X (3D Systems, Inc, Rock Hill, SC), and data were collected as both numerical values and color-coded deviation maps. Superimposition data were segmented for each arch (anterior, posterior right, and posterior left) to determine if the arch location was a relevant factor. All post-debond and VBR STL files were 3D printed. Thermoplastic retainers were fabricated on each 3D-printed model. Retainers were delivered to patients and clinically graded by 2 practitioners., Results: There was a statistically significant difference in standard deviation and out-of-tolerance percentage values when comparing traditional debonded arches and virtually debonded arches when using sextant locations as a factor (anterior, posterior right, and posterior left). Grading scores for both evaluators show a statistically significant difference for the evaluation of facial surface adaptation and snap-fit acceptability between retainer fabrication methods. However, there was no correlation between out-of-tolerance values and clinical retainer fit evaluation among any of the graded variables in either the maxillary or mandibular arches., Conclusions: VBR by AI is considered accurate enough to be used for the fabrication of clinically acceptable thermoplastic orthodontic retainers., (Copyright © 2024 American Association of Orthodontists. All rights reserved.)

Microcystins (MCs) from freshwater cyanobacteria cause adverse effects to humans and ecological receptors through multiple exposure routes requiring adaptable and diverse treatment technologies. Photocatalysis of MCs using TiO 2 is a promising technology; however, TiO 2 photocatalysts as unbound nanoparticles in suspension are impractical to deploy. 3D Printing (3DP) provides a means to immobilize TiO 2 , producing deployable photocatalyst structures with extensive geometric freedom. The objective of this proof-of-concept experiment was to incrementally increase the environmental complexity (e.g., broad-spectrum fluorescent lamps and outdoor solar; filtered cell lysate and algal assemblage as the source of MCs) while comparing photocatalysis rates of MCs by 3DP TiO 2 structures using polylactic acid (PLA) as the binder. Degradation half-lives of MCs were shorter in TiO 2 embedded in 3DP PLA relative to PLA-only controls with differences in half-lives ranging from 3.6 to 10h. The one exception was the outdoor solar and an algal assemblage, where significant differences could not be discerned due to the already rapid photolysis rates. Ultimately, photocatalysis rates (half-life = 1.9-11.6h) were comparable to those previously published for TiO 2 3DP structures in a laboratory environment and TiO 2 fixed-films (half-life = 2-13h) demonstrating feasibility of 3DP to immobilize TiO 2 photocatalysts under a range of conditions. This is the first time that MC concentrations from a field-collected HAB were photocatalytically degraded in both solar simulated light and sunlight using a custom-made advanced photocatalytic nano-composite with enhanced performance through high surface area design enabled by 3D printing. These data inform future development of scalable, retrievable, and operationally flexible structures with immobilized TiO 2 ., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier Ltd.)

Objective: The objective was to investigate the dimensional stability of different types of 3D printed dental models, and to measure the dimensional changes over time., Methods: Four dental casts with different constructions were printed. The four types of models were as follows: hollow casts with 2.5 mm wall thickness (2,5mm.H), hollow casts with 2 mm wall thickness (2mm.H), hollow casts with 2 mm wall thickness with stabilization bars (2mm.B) and hollow casts with 2 mm wall thickness with gypsum base (2mm.G). The casts were digitized with a laboratory scanner (3Shape E3 Red E Scanner) to obtain the reference Standard Tessellation Language (STL) files. All models were stored at room temperature and scanned again after 1 day and after 1, 2 and 10 weeks. This data was compared to the reference STL file and was analysed by comparing the deformation using surface fitting software (Geomagic Control X, 3D Systems). The results were statistically evaluated using paired Student's t-tests, with the significance level set at p < 0.05., Results: There were significant differences in dimensional stability after 10 weeks between the four different dental casts. According to our results, the 2mm.B casts showed the least deformation which was followed by the 2mm.H casts. However, both the 2,5mm.H and the 2mm.G casts showed significant deformation compared to the 2mm.B casts., Conclusions: Within the limitations of this study - using only one printer and one type of resin - we found that the deformation of all investigated casts remained within the clinically acceptable range. However, there were significant differences between the various construction types printed with the Bego Varseo Printer and Bego Varseo Wax Model Gray material., Clinical Significance: It is crucial to determine how long 3D printed models can maintain their accuracy to prevent potential adverse effects, especially given the extended storage periods required for the time-consuming procedures in prosthodontic and orthodontic treatments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Extrusion-based 3D printing methods have great potential for manufacturing of personalized polymer-based drug-releasing systems. However, traditional melt-based extrusion techniques are often unsuitable for processing thermally labile molecules. Consequently, methods that utilize the extrusion of semi-solid inks under mild conditions are frequently employed. The rheological properties of the semi-solid inks have a substantial impact on the 3D printability, making it necessary to evaluate and tailor these properties. Here, we report a novel semi-solid extrusion 3D printing method based on utilization of a Carbopol gel matrix containing various concentrations of polymeric microspheres. We also demonstrate the use of a solvent vapor-based post-processing method for enhancing the mechanical strength of the printed objects. As our approach enables room-temperature processing of polymers typically used in the pharmaceutical industry, it may also facilitate the broader application of 3D printing and microsphere technologies in preparation of personalized medicine., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Juuso Pohjola reports equipment, drugs, or supplies was provided by Bayer Oy. Juuso Pohjola reports a relationship with Bayer Oy that includes: employment. Mikael Stolt reports a relationship with Bayer Oy that includes: employment. Mika Jokinen reports a relationship with DelSiTech Ltd that includes: employment. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)