Adaptation and Biomechanical Performance of Custom-Fit Mouthguards Produced Using Conventional and Digital Workflows: A Comparative In Vitro Strain Analysis.

BACKGROUND/OBJECTIVES: The use of different models for the fabrication of custom-fit mouthguards (MTGs) can affect their final thickness, adaptation, and shock-absorption properties. This study aimed to evaluate the adaptation, thickness, and shock absorption of ethylene-vinyl acetate (EVA) thermoplastic MTGs produced using conventional plaster or three-dimensional (3D) printed models. MATERIALS AND METHODS: A typical model with simulated soft gum tissue was used as the reference model to produce MTGs with the following two different protocols: plast-MTG using a conventional impression and plaster model (n = 10) and 3DPr-MTG using a digital scanning and 3D printed model (n = 10). A custom-fit MTG was fabricated using EVA sheets (Bioart) plasticized over different models. The MTG thickness (mm), internal adaptation (mm) to the typodontic model, and voids in the area (mm2) between the two EVA layers were measured using cone-beam computed tomography images and Mimics software (Materialize). The shock absorption of the MTG was measured using a strain-gauge test with a pendulum impact at 30° with a steel ball over the typodont model with and without MTGs. Data were analyzed using one-way analysis of variance with repeated measurements, followed by Tukey's post hoc tests. RESULTS: The 3DPr-MTG showed better adaptation than that of the Plast-MTG at the incisal/occlusal and lingual tooth surfaces (p < 0.001). The 3DPr-MTG showed a thickness similar to that of the Plast-MTG, irrespective of the measured location. MTGs produced using both model types significantly reduced the strain values during horizontal impact (3DPr-MTG 86.2% and Plast-MTG 87.0%) compared with the control group without MTG (p < 0.001). CONCLUSION: The MTGs showed the required standards regarding thickness, adaptation, and biomechanical performance, suggesting that the number and volume of voids had no significant impact on their functionality. Three-dimensional printed models are a viable alternative for MTG production, providing better adaptation than the Plast-MTG at the incisal/occlusal and lingual tooth surfaces and similar performance as the MTG produced with the conventional protocol.

Which is more effective? Porcine tendon or 3D- printed flexor tendon? A study of model realism and educational utility in a flexor tendon repair workshop.

Introduction: Animal models in orthopaedic surgical training have raised concerns about ethics and availability, prompting the search for non-animal alternatives. The 3D-printed silicone tendon model has emerged as a potential alternative due to its hygiene and reusability. This study aimed to compare the effectiveness of the two models for flexor tendon repair training. Materials and methods: A survey involved 25 postgraduate trainees with no prior experience in flexor tendon repair. Porcine tendon models and 3D-printed models were used, with participants evaluating accuracy, understanding of pulley systems, joint flexion, tissue feel, and model realism. Repairs were evaluated by experienced surgeons, and participants completed a survey. Results: Both models demonstrated satisfactory accuracy and realistic joint flexion. The porcine model scored higher in anatomical accuracy, while the 3D-printed model excelled in understanding pulley systems. The porcine model provided realistic tissue feel, while the 3D-printed model facilitated anatomy teaching. No significant difference was found in educational utility. The 3D-model was perceived as hygienic and odourless, whereas the porcine model offered better tendon handling. The 3D-model improved visualization of suture placement. Both models were equally accepted and recommended for training. Conclusion: The 3D-printed silicone tendon model is a cost-effective and reproducible alternative to porcine models in flexor tendon repair training. Although the 3D-printed model has limitations in mimicking human tendons, it was equally effective in teaching suturing techniques and improving repair skills. Combining the porcine model and 3D-printed model provides a comprehensive approach to flexor tendon repair training, addressing the limitations of each model and enhancing the educational experience.

Biomechanical assessment and comparison of fixation methods for bilateral sacroiliac joint luxation in 3D-printed feline pelvic bone models.

Background and Aim: Bilateral sacroiliac joint luxation, a condition primarily observed in cats, can significantly impact their quality of life. This study aimed to compare a control with three distinct fixation methods to identify the most robust fixation method capable of withstanding significant tensile stress. Materials and Methods: Twenty pelvic bone models of cats were made using a 3D printer with polylactic acid plastic. Each model was assembled by cutting the sacroiliac joints and pelvic girdle symphysis with a handsaw, then bonded with cyanoacrylate glue. 3D feline pelvic bone models were categorized into four significant groups, each consisting of five models. The study discovered that the three groups used distinct fixation methods: Two lag screws (DS), K-wires at the ilium wing and sacroiliac joints (TK), and K-wires at the sacroiliac joints (DK). The final group, not fixed, was the control. Results: The results were characterized further through a mechanical compression force test using a universal testing machine. The most robust method at the sacroiliac joints, the DK technique, sustained a maximum force of up to 183.86 N while maintaining the correct bone alignment. The fixation method is more accessible and faster to implement in comparison to the DS method. Conclusions: The DK group exhibited the greatest maximum load capacity among all groups. Sacroiliac joint luxation treatment can effectively be addressed using the K-wires fixation method. However, the DK need space of sacral body same as DS for fixation. Further clinical study should be performed.

Integration of 3D printing and case-based learning in clinical practice for the treatment of developmental dysplasia of the hip.

BACKGROUND: Case-based learning (CBL) utilizing three-dimensional (3D) printed hip joint models is a problem-solving teaching method that combines the tactile and visual advantages of 3D-printed models with CBL. This study aims to investigate the impact of integrating 3D printing with CBL on learning developmental dysplasia of the hip (DDH). METHODS: We conducted a prospective study from 2022 to 2023, including 120 fourth-year clinical medical students at Xuzhou Medical University. Students were randomly allocated into two groups of 60 participants each. The CBL group received conventional CBL teaching methods, while the 3D + CBL group utilized 3D-printed models in conjunction with CBL. Post-teaching, we analyzed and compared the theoretical and practical achievements of both groups. A questionnaire was designed to assess the impact of the educational approach on orthopedic surgery learning. RESULTS: The theory scores of the CBL group (62.88 ± 7.98) and 3D + CBL group (66.35 ± 8.85) were significantly different (t = 2.254, P = 0.026); the practical skills scores of the CBL group (57.40 ± 8.80) and 3D + CBL group (63.42 ± 11.14) were significantly different (t = 3.283, P = 0.001). The questionnaire results showed that the 3D + CBL group was greater than the CBL group in terms of hip fundamentals, ability to diagnose cases and plan treatments, interesting teaching content, willingness to communicate with the instructor and satisfaction. CONCLUSIONS: The integration of 3D printing with case-based learning has yielded positive outcomes in teaching DDH, providing valuable insights into the use of 3D-printed orthopedic models in clinical education.

Biomechanical Analysis of Pedicle Screw Reinsertion Along the Same Trajectory in a Validated 3D-Printed Synthetic Bone Model.

OBJECTIVE: To investigate the biomechanical properties of pedicle screw reinsertion along the same trajectory in a previously validated synthetic bone model. METHODS: Twenty identical acrylonitrile butadiene styrene models of lumbar vertebrae were three-dimensional-printed. Screws were placed in the standard fashion into each pedicle. Models were separated into 2 equal groups, control and experimental. Experimental group screws were completely removed from their testing block and reinserted once. All screws in both groups were then forcibly removed. Continuous torque monitoring was collected on screw insertion torque (IT), removal torque, and reinsertion torque. Pullout strength (PO), screw stiffness (STI), and strain energy (STR) were calculated. RESULTS: There was no significant difference between control and experimental groups for PO (P = 0.26), STI (P = 0.55), STR (P = 0.50), or IT (P = 0.24). There was a significant decrease in reinsertion torque (54.5 N-cm ± 8.2 N-cm) from control IT (62.9 N-cm ± 8.4 N-cm, P = 0.045) and experimental IT (67.5 N-cm ± 7.6 N-cm, P = 0.0026). Strong correlations (Pearson's r > 0.80) were seen between control IT against STR and PO, between each of the experimental torque measurements, and between experimental PO and STI. CONCLUSIONS: Despite a significant decrease in insertion torque, there is no significant loss of pedicle screw performance when a screw is removed and reinserted along the same trajectory.

Comparison of the efficacy of Er,Cr:YSGG laser on oral biofilm removal from implant surfaces with various application times for the treatment of peri-implantitis defects: ex vivo study.

PURPOSE: The major struggle in peri-implantitis therapy is the availability of successful decontamination of the infected implant surface. The main hypothesis of this study was the Er,Cr: YSGG laser decontamination efficacy investigation on the infected implant surfaces with various peri-implantitis defects. The primary objective of this study was to decide the efficacy of Er,Cr:YSGG laser as a decontamination tool at various peri-implantitis simulating defects. The secondary objective was to compare the efficacy of the Er,Cr: YSGG laser on oral biofilm removal between two protocols the first protocol (4 cycles at 2.5 min) and the second protocol (5 cycles at 5 min) at various peri-implantitis simulating defects. MATERIALS AND METHODS: A total of 3 subjects whose plaque biofilms formed in-vivo on twenty-four tested implants were divided into four tested groups. Two native implants were tested as controls.The in vitro defect model was computer-aided designed and printed into a 3D-printed model with various anulations in peri-implant infrabony defects, which were 15,30,60,and 90 degrees. RESULTS: Both Er, Cr: YSGG decontamination protocols at 50 mJ (1.5 W/30 Hz), 50% air, and 40% water were effective at reducing the total implant surface area/ biofilm ratio (%), but the second protocol had a markedly greater reduction in the duration of application (5 cycles at 5 min) than did the first protocol (4 cycles at 2.5 min). CONCLUSION: The Er, Cr: YSGG laser is an effective decontamination device in various peri-implantitis defects. The second protocol(5 cycles at 5 min) with greater application time and circles is more effective than the first one. The defect angulation influence the decontamination capability in peri-implantitis therapy. CLINICAL RELEVANCE (SCIENTIFIC RATIONALE FOR STUDY): Clinicians anticipate that the exploration of suitable therapeutic modalities for peri-implantitis therapy is limited by the obvious heterogeneity of the available evidence in the literature and need for a pre-clinical theoretical basis setup. The major challenges associated with peri-implantitis therapy include the successful decontamination of the infected implant surface, the absence of any damage to the treated implant surface with adequate surface roughness, and the biocompatibility of the implant surface, which allows osteoblastic cells to grow on the treated surface and is the key for successful re-osseointegration. Therefore, these are the expected empirical triads that need to be respected for successful peri-implantitis therapy. Failure of one of the triads represents a peri-implantitis therapeutic failure. The Er, Cr: YSGG laser is regarded as one of the expected devices for achieving the required triad. TRIAL REGISTRATION: "Efficacy of Er,Cr YSGG Laser in Treatment of Peri-implantitis". CLINICALTRIALS: gov ID NCT05137821. First Posted date: 30 -11-2021.

Specialized educational program for high-grade liver injury management: a three-dimensional printed model approach.

PURPOSE: The study aims to present a specialized educational program using a 3D printed model for managing Grade IV and V liver injuries. Hepatic packing, a common technique, may not always achieve sufficient hemostasis in these cases, warranting alternative solutions such as mesh liver wrapping. However, mastering this procedure is challenging due to limited teaching resources and the need for repeated practice. METHODS: A computer-based model was created from an abdominal CT scan to produce a real-sized injured liver model using thermoplastic elastomer TPU-95. Trainees received systematic instruction from an instructor, allowing them to perform the procedure under supervision and independently. RESULTS: Eight surgical residents at Hillel Yaffe Medical Center participated in the program, with the majority successfully completing the procedure under supervision. Furthermore, trainees demonstrated reduced procedure times when performing independently, indicating improved proficiency. CONCLUSION: This educational approach offers a simple and repeatable method for continuous training in managing high-grade liver injuries, holding potential for enhanced patient outcomes.

Precise planning based on 3D-printed dry-laboratory models can reduce perioperative complications of laparoscopic surgery for complex hepatobiliary diseases: a preoperative cohort study.

BACKGROUND & AIMS: Complications after laparoscopic liver resection (LLR) are important factors affecting the prognosis of patients, especially for complex hepatobiliary diseases. The present study aimed to evaluate the value of a three-dimensional (3D) printed dry-laboratory model in the precise planning of LLR for complex hepatobiliary diseases. METHODS: Patients with complex hepatobiliary diseases who underwent LLR were preoperatively enrolled, and divided into two groups according to whether using a 3D-printed dry-laboratory model (3D vs. control group). Clinical variables were assessed and complications were graded by the Clavien-Dindo classification. The Comprehensive Complication Index (CCI) scores were calculated and compared for each patient. Multivariable analysis was performed to determine the risk factors of postoperative complications. RESULTS: Sixty-two patients with complex hepatobiliary diseases underwent the precise planning of LLR. Among them, thirty-one patients acquired the guidance of a 3D-printed dry-laboratory model, and others were only guided by traditional enhanced CT or MRI. The results showed no significant differences between the two groups in baseline characters. However, compared to the control group, the 3D group had a lower incidence of intraoperative blood loss, as well as postoperative 30-day and major complications, especially bile leakage (all P < 0.05). The median score on the CCI was 20.9 (range 8.7-51.8) in the control group and 8.7 (range 8.7-43.4) in the 3D group (mean difference, -12.2, P = 0.004). Multivariable analysis showed the 3D model was an independent protective factor in decreasing postoperative complications. Subgroup analysis also showed that a 3D model could decrease postoperative complications, especially for bile leakage in patients with intrahepatic cholelithiasis. CONCLUSION: The 3D-printed models can help reduce postoperative complications. The 3D-printed models should be recommended for patients with complex hepatobiliary diseases undergoing precise planning LLR.

The utilization of three-dimensional imaging and three-dimensional-printed model in autologous microtia reconstruction.

Background: The use of three-dimensional (3D) technology helps surgeons in performing autologous microtia reconstruction due to more accurate measurements and a better precision template model. However, the technical aspects of using a 3D imaging and 3D-printed model and the difference in outcomes postoperatively remain poorly reviewed. Purpose: This systematic review aimed to provide the current evidence of the benefit and technical aspects of using 3D technology in autologous microtia reconstruction. Method: A systematic literature search was conducted across multiple databases: Medline, Embase, Google Scholar, and Central until June 2022. Studies that evaluated the use of 3D imaging or 3D-printed models for autogenous microtia reconstruction were selected. The quality of the included studies was also assessed with respect to the study design. Result: A systematic literature search yielded 17 articles with a combination of observational and case report studies. Overall, 3D imaging showed a precise measurement for preoperative costal cartilage assessment. Compared to the 2D template, the utilization of a 3D-printed template provided a higher similarity rate relative to the unaffected ear, higher patient and surgeon satisfaction, and lower surgical time. Most 3D templates were fabricated using polylactic acid material on fused deposition modelling printers. The template costs were ranging from $1 to $4.5 depending on the material used. Conclusion: 3D imaging and 3D-printed templates could improve the outcome of autologous microtia reconstruction. However, the quality of the existing evidence remains low due to the heterogeneity of the reported outcomes. Further studies with more adequate comparability and defined outcomes are still required.

Optimized reusable modular 3D-printed models of choledochal cyst to simulate laparoscopic and robotic bilioenteric anastomosis.

Laparoscopic and robotic surgery is a challenge to the surgeon's hand-eye coordination ability, which requires constant practice. Traditional mentor training is gradually shifting to simulation training based on various models. Laparoscopic and robotic bilioenteric anastomosis is an important and difficult operation in hepatobiliary surgery. We constructed and optimized the reusable modular 3D-printed models of choledochal cyst. The aim of this study was to verify the ability of this optimized model to distinguish between surgeons with different levels of proficiency and the benefits of repeated practice. A total of 12 surgeons with different levels participated in the study. Operation completion time and OSATS score were recorded. The model was validated by Likert scale. Surgeons were shown the steps and contents before performing laparoscopic or robotic bilioenteric anastomosis using the model. Surgeons with different levels of experience showed different levels when performing laparoscopic bilioenteric anastomosis on this model. Repeated training can significantly shorten the time of laparoscopic bilioenteric anastomosis and improve the operation scores of surgeons with different levels of experience. At the same time, preliminary results have shown that the performance of surgeons on the domestic robotic platform was basically consistent with their laparoscopic skills. This model may distinguish surgeons with different levels of experience and may improve surgical skills through repeated practice. It is worth noting that in order to draw more reliable conclusions, more subjects should be collected and more experiments should be done in the future.

Factors affecting the intraoperative calculi excretion during flexible ureteroscopy lithotripsy: an in vitro analysis.

OBJECTIVE: To explore the parameters influencing intraoperative calculi excretion (ICE) during flexible ureteroscopy lithotripsy (fURL) using in vitro simulation experiments. METHODS: 3D-printed human kidney models were used to simulate the elimination of gravel during fURL. The factors influencing the ICE during fURL were analyzed by comparing the effects of different degrees of hydronephrosis (mild, moderate, and severe), surgical positions (supine and lateral position), ratios of endoscope-sheath diameter (RESD) (0.625, 0.725, and 0.825), gravel sizes (0.50-1.00 mm, 0.25-0.50 mm, and 0.10-0.25 mm), and ureteral access sheaths (UASs) (traditional UAS and negative-pressure UAS) on ICE. RESULTS: The impacts of various UAS, RESD, degree of hydronephrosis, surgical positions, and gravel sizes on ICE were all significant (p < 0.05). We found no evidence of multicollinearity for all the independent variables, and the linear regression equation fitted as ICE ( g / min ) = 0.102 + 0.083 ∗ UAS grade - 0.050 ∗ RESD grade - 0.048 ∗ hydronephrosis grade + 0.065 ∗ position grade - 0.027 ∗ gravel size grade (R2 = 0.569). CONCLUSION: Employing negative-pressure UAS, smaller RESD, milder hydronephrosis, lateral position, and smaller gravel size contribute to improved ICE during fURL. Among them, the adoption of negative-pressure UAS had the most substantial effects.

Use of reconstruction plates prebent on three-dimensional models to reduce the complications of mandibular reconstruction.

Background/purpose: Though the gold standard method for mandible reconstruction of the defect from segmental mandibulectomy is by osseous flap or graft, using reconstruction plates is still indicated in some cases. Traditionally, the plate is bended immediately after the segmental mandibulectomy by freehand. However, it's difficult to fit well to the original position of mandible, which may result in more complications. This study therefore aimed to investigate whether using prebent plates on computer-aided 3D printing models could reduce the complication rate. Materials and methods: Patients who received mandible reconstruction by reconstruction plate from 2018 to 2022 were enrolled and evaluated in this study. The data, including demographics, indications for surgery, pre-existed preoperative and postoperative therapies, classification of defects, and postoperative outcomes were collected and analyzed. Results: A total of 52 patients were enrolled in our study. The prebent group exhibited a significantly lower complication rate than that of the immediately bent group (P = 0.012). Other risk factors of plate complications included postoperative adjuvant radiotherapy (P = 0.017) and previous surgery (P = 0.047). The complication-free survival rate was also better in the prebent group in a 3-year follow-up period (P = 0.012). Conclusion: Prebent plates on computer-aided printing models proved to be an effective approach to reduce the complications for mandibular reconstruction in segmental mandibulectomy.

Development of a 3D-printed neonatal congenital diaphragmatic hernia model and standardisation of intra-operative measurement.

INTRODUCTION: Three-dimensional (3D) printing is frequently used for surgical simulation and training, however, no widely available model exists for neonatal congenital diaphragmatic hernia (CDH). The aim of this study was to develop a 3D-printed model of CDH and test interobserver variability in the simulated model for obtaining measurements of the diaphragmatic defect and ipsilateral diaphragm. METHODS: A term fetal MRI (3.5 kg) of thorax, diaphragm and defect (15 mm × 5 mm) were delineated and segmented after parental consent to produce 3D-printed models. Consultant and trainee paediatric surgeons were invited to measure the posterior-lateral diaphragmatic defect and ipsilateral diaphragm. Mean measurement error was calculated (millimetres). Data are presented as median (range) and number/total (%). RESULTS: An abdominal and thoracoscopic model were produced and tested by 52 participants (20 consultants and 32 trainees). Diaphragmatic defect via laparotomy measured 15 (10-20) mm (AP) × 16 (10-25) mm (ML) and thoracoscopically 14 (11-19) mm (AP) × 15 (11-22) mm (ML). Mean error per measurement was 4 (1-17) mm via laparotomy vs. 3 (0.5-9.5) mm thoracoscopically. Mean error was similar between consultants and trainees via laparotomy (4.3 vs. 3.9 mm, p = 0.70) and thoracoscopically (3 vs. 3 mm, p = 0.79). Error did not correlate with experience as operating surgeon via laparotomy (ß = 13.0 [95% CI - 55.9 to 82.0], p = 0.71) or thoracoscopically (ß = 1.4[95% CI - 6.4 to 9.2], p = 0.73. CONCLUSIONS: We have designed and built simulation models for CDH repair via laparotomy and thoracoscopically. Operators can reliably measure the diaphragmatic defect and ipsilateral diaphragm, regardless of surgical experience and operative approach.

Effect of different materials for conventional and 3D-printed models on the mechanical properties of ethylene-vinyl acetate utilized for fabricating custom-fit mouthguards.

BACKGROUND/AIM: The interaction between the ethylene-vinyl acetate (EVA) with distinct materials utilized for obtaining dental models can affect the performance of resulting mouthguards. This study attempted to evaluate the effect of different materials for conventional (dental stone) or 3D-printed (resin) models on EVA's physical and mechanical properties and surface characteristics. MATERIAL AND METHODS: EVA sheets (Bioart) were laminated over four model types: GIV, conventional Type IV dental stone model (Zhermak); ReG, resin-reinforced Type IV dental stone model (Zero Stone); 3DnT, 3D resin printed model (Anycubic) without surface treatment; 3DT, 3D-printed model (Anycubic) with water-soluble gel (KY Jelly Lubricant, Johnson & Johnson) coating during post-curing process. The EVA specimens were cut following the ISO 37-II standard (n = 30). Shore A hardness was measured before and after plasticization on the contact (internal) or opposite (external) surfaces with the model. The breaking force (F, N), elongation (EL, mm), and ultimate tensile strength (UTS, MPa) were measured using a universal testing machine. Macro-photography and scanning electron microscopy were adopted for classifying the EVA surface alteration. Data were analyzed by one-way ANOVA with repeated measures, followed by Tukey's test (α = .05). RESULTS: Plasticization significantly decreased Shore A values for the tested EVA regardless of the model type (p < .001). Higher F, El, and UTS values were verified for the EVA with 3DT and GIV models compared to ReG and 3DnT (p < .001). 3DnT models resulted in severe surface alteration and a greater reduction of the mechanical properties of the EVA. CONCLUSION: The interaction of EVA with 3D resin-printed models without surface treatment or resin-reinforced Type IV dental stone models significantly affected the physical and mechanical properties of this material. The utilization of water-soluble gel coating during the post-curing process of 3D resin printed models improved the mechanical properties of the EVA, similarly when this material was plasticized over conventional Type IV dental stone model.

3D print model for surgical planning in a case of recurrent osteoblastic osteosarcoma of the left maxilla. A case report.

Osteosarcoma (OS) of the head and neck is a rare and aggressive disease characterized by the formation of osteoid by malignant osteoblasts. The mandible or maxilla are the most common sites of presentation. Radiologically, these tumors show considerable, destructive growth with periosteal reaction, which can suggest the diagnosis of OS. 3D printing, as an emerging technology, can play a role in orthopedic oncology by providing patient-specific 3D printed models to improve surgical planning and facilitate patient understanding. We present the case of a male in his early 30s with a final histological diagnosis of recurrent osteosarcoma of the left maxilla, where a 3D printed model was helpful for the diagnostic workup, surgical planning, and the procedure.

Short-term results and complications of the operative treatment of the distal radius fracture AO2R3 C type, planned by using 3D-printed models. Prospective randomized control study.

PURPOSE: 3D-printed models rapidly evolving in orthopaedic. Studies show that 3D-printed models used for preoperative planning improve a better understanding of fracture morphology and reduce operative time, blood loss and frequency of fluoroscopy, but there are no studies that investigated possible advantages in the outcomes and complications for the treatment of distal radius fracture (DRF). Our study aims to evaluate short-term functional results and complications between two groups treated DRF using 3D-printed models for preoperative planning and without. We hypothesize that the addition of 3D-printed models would improve functional outcomes and reduce complication rates. METHODS: 66 randomized cases of DRF AO/OTA C type were enrolled and divided into "Control group" (n = 33) and "3D-printed model group" (n = 33). Personalized 3D-printed models were created. The primary outcomes were: Patient-Rated Wrist Evaluation questionnaire, Quick Disabilities of the Arm, Shoulder and Hand Score questionnaire, and complications. The secondary outcomes were: measurement of the range of motions, grip strength, radiological evaluation, and the visual analogue scale. Assessments were measured at 6 weeks, 3 months, and 6 months intervals. RESULTS: We found that the integration of the 3D-printed model in preoperative planning decreased complication incidence significantly - from 30.3% in the "Control group" to 6.1% in the "3D-printed model group", p = .022. But we did not find a difference in functional and radiological outcomes. CONCLUSION: The 3D-printed models for preoperative planning surgically treating DRF AO/OTA C type can help minimize the complication rate, however, they can't improve functional outcomes in the short-term results. LEVEL OF EVIDENCE: Level I randomized controlled study.

The Use of 3D Printed Models for Surgical Simulation of Cranioplasty in Craniosynostosis as Training and Education.

BACKGROUND: The advance in imaging techniques is useful for 3D models and printing leading to a real revolution in many surgical specialties, in particular, neurosurgery. METHODS: We report on a clinical study on the use of 3D printed models to perform cranioplasty in patients with craniosynostosis. The participants were recruited from various medical institutions and were divided into two groups: Group A (n = 5) received traditional surgical education (including cadaveric specimens) but without using 3D printed models, while Group B (n = 5) received training using 3D printed models. RESULTS: Group B surgeons had the opportunity to plan different techniques and to simulate the cranioplasty. Group B surgeons reported that models provided a realistic and controlled environment for practicing surgical techniques, allowed for repetitive practice, and helped in visualizing the anatomy and pathology of craniosynostosis. CONCLUSION: 3D printed models can provide a realistic and controlled environment for neurosurgeons to develop their surgical skills in a safe and efficient manner. The ability to practice on 3D printed models before performing the actual surgery on patients may potentially improve the surgeons' confidence and competence in performing complex craniosynostosis surgeries.

Cerebrovascular modelling for the management of aneurysm embolization using an intrasaccular flow diverter made by 3D printing.

Purpose: Using 3-dimensional (3D) printers, the creation of patient-specific models is possible before and after a therapeutic intervention. There are many articles about replicas for training and simulation of aneurysm clipping. However, no paper has focused on 3D replicas obtained from 3-tesla 3D time of flight (3D-TOF) MR angiography for intrasaccular flow diverter (WEB device) embolization of the cerebral aneurysms. In this paper, we aimed to investigate the feasibility of 3D printing models obtained from 3-tesla 3D-TOF data in the management and training of WEB-assisted embolization procedures. Case presentation: We presented a longitudinal case report with several 3D-TOF MRA prints over time. Three-tesla 3D-TOF data were converted into STL and G-code files using an open-source (3D-Slicer) program. We built patient-specific realistic 3D models of a patient with a middle cerebral artery trifurcation aneurysm, which were able to demonstrate the entire WEB device treatment procedure in the pre-intervention and post-intervention periods. The aneurysmatic segment was well displayed on the STL files and the 3D replicas. They allowed visualization of the aneurysmatic segment and changes within a 6-year follow-up period. We successfully showed the possibility of fast, cheap, and easy production of replicas for demonstration of the aneurysm, the parent vessels, and post-intervention changes in a simple way using an affordable 3D printer. Conclusions: 3D printing is useful for training the endovascular team and the patients, understanding the aneurysm/parent vessels, and choosing the optimal embolization technique/device. 3D printing will potentially lead to greater interventionalist confidence, decreased radiation dose, and improvements in patient safety.

Efficacy of an interdental brush in cleaning artificial plaque on a 3D-printed model base.

BACKGROUND: Among interdental cleaning aids (ICAs), interdental brushes (IDBs) are in the spotlight because they can effectively remove plaque from interdental surfaces. Guidance on the correct use of ICAs, such as IDBs, is required to prevent dental plaque accumulation. Since it is impossible to confirm the interdental proximal surface unless extracted, it is difficult to conduct quantitative experiments. This study presented an efficient way to evaluate IDBs by realizing dental structures and embrasures using a Dental computer-aided design (CAD) software and a 3D printer. METHODS: Two different sizes of embrasure (0.7 and 1.2 mm) crown models were prepared with CAD software and a 3D printer. To evaluate the cleaning efficacy of IDBs of each size (0.6, 0.7, 0.8, 1.0, 1.2, and 1.5 mm diameters), the 9th cycle of brush move was performed where artificial plaque was spread and a digital camera was used to record the process. The pixels and percentage of cleaning from the recorded digital images were analyzed. RESULTS: The plateau was formed after the 5th brushing cycle under all conditions-after the 5th cycle, the cleaning efficacy of the two crown models was 69.3-86.4% and 49.8-75.4%. In these results, the optimal diameters for the IDB were 1.2 and 1.5 mm for embrasure sizes of 0.7 and 1.2 mm, respectively. Moreover, the cleaning efficacy was the highest at 86.4% and 75.4% after the 9th cycle. CONCLUSIONS: The 3D-printed model base for the human oral embrasure structure is an adequate model to test artificial plaque removal using IDB. The use of IDBs for more than five cycles does not support the conventional idea that a greater number of IDB brushing moves is more effective in a statistically substantial manner.

Fabrication of Thermo-Responsive Controllable Shape-Changing Hydrogel.

Temperature response double network (DN) hydrogels comprising a network formed by polymerization of methacrylic acid (MA) modified PVA, N,N'-methylene bis(acrylamide), N-isopropylacryl amide (NIPAM), and one formed from crystalline polyvinyl alcohol (PVA) are prepared in a 3D printed tailor-made mold. The (PVA-MA)-g-PNIPAAm thermoset intermediate is formed in water by a radical, photo-initiated process, and in the presence of dissolved PVA polymers. A subsequent freezing-thawing sequence induces the crystallization of the PVA network, which forms a second network inside the thermoset NIPAM polymer. The prepared hydrogel is thermoresponsive by the phase transition of PNIPAAm segments (T ≈ 32 °C) and has good mechanical properties (tensile strength 1.23 MPa, compressive strength 1.47 MPa). Thermal cycling between room temperature at 40 or 50 °C shows the product converses from a virgin-state to a steady-state, which most likely involves the reorganization of PVA crystals. The swelling-deswelling cycles remain clear at a length change of about 13%.