Monomer elution and shrinkage stress analysis of addition-fragmentation chain-transfer-modified resin composites in relation to the curing protocol.

OBJECTIVE: The purpose was to compare the effects of rapid (3 s) and conventional (20 s) polymerization protocols (PP) of mono- and multichip LED curing units (LCU) on shrinkage stress (SS) and monomer elution (ME) in bulk-fill resin-based composites (RBC) with and without addition-fragmentation chain-transfer (AFCT) monomer. METHODS: Cylindrical (5x4mm) specimens were prepared from two RBCs containing different AFCT monomers (Filtek OneBulk-FOB; Tetric PowerFill-TPF) and one without (Tetric EvoCeram Bulk-TEC). After soaking for 3, 10, and 14 days (75 % ethanol), ME was quantified using standard monomers by High-Performance Liquid Chromatography. SS was measured from the start of polymerization to 5 min using a Materials Testing Machine. The radiant exitance of LCUs was measured using a spectrophotometer. ANOVA and Tukey's post-hoc test, multivariate analysis and partial eta-squared statistics were used to analyze the data (p < 0.05). RESULTS: AFCT-modification significantly decreased ME (p < 0.001). ME was reduced by half by day 10 and by one tenth by the end of the 14-day compared to the 3-day sampling. ME itself was dependent, whereas the percentage of monomers released was independent of the PP used (p > 0.05). FOB showed the lowest SS (p < 0.001), while there was no significant difference between TPF and TEC (p = 0.124). Both ME and SS were significantly influenced by material type and PP. SIGNIFICANCE: The incorporation of the AFCT monomer reduced ME, but this was inversely related to a decrease in exposure time. SS values reduced by rapid PP in parallel with increasing ME values. The utilization of the AFCT molecule in conjunction with an appropriate resin-, initiator-system is of significant consequence for the kinetics of polymerization and the incorporation of monomers into the network.

Comparison of Macintosh Laryngoscope, King Vision®, VividTrac®, AirAngel Blade®, and a Custom-Made 3D-Printed Video Laryngoscope for Difficult and Normal Airways in Mannequins by Novices-A Non-Inferiority Trial.

Background: Endotracheal intubation (ETI) is a cornerstone of airway management. The gold standard device for ETI is still the direct laryngoscope (DL). However, video laryngoscopes (VLs) are now also widely available and have several proven advantages. The VL technique has been included in the major airway management guidelines. During the COVID-19 pandemic, supply chain disruption has raised demand for 3D-printed medical equipment, including 3D-printed VLs. However, studies on performance are only sparsely available; thus, we aimed to compare 3D-printed VLs to the DL and other VLs made with conventional manufacturing technology. Methods: Forty-eight medical students were recruited to serve as novice users. Following brief, standardized training, students executed ETI with the DL, the King Vision® (KV), the VividTrac® (VT), the AirAngel Blade® (AAB), and a custom-made 3D-printed VL (3DVL) on the Laerdal® airway management trainer in normal and difficult airway scenarios. We evaluated the time to and proportion of successful intubation, the best view of the glottis, esophageal intubation, dental trauma, and user satisfaction. Results: The KV and VT are proved to be superior (p < 0.05) to the DL in both scenarios. The 3DVL's performance was similar (p > 0.05) or significantly better than that of the DL and mainly non-inferior (p > 0.05) compared to the KV and VT in both scenarios. Regardless of the scenario, the AAB proved to be inferior (p < 0.05) even to the DL in the majority of the variables. The differences between the devices were more pronounced in the difficult airway scenario. The user satisfaction scores were in concordance with the aforementioned performance of the scopes. Conclusions: Based upon our results, we cannot recommend the AAB over the DL, KV, or VT. However, as the 3DVL showed, 3D printing indeed can provide useful or even superior VLs, but prior to clinical use, meticulous evaluation might be recommended.

Validation of a novel, low-fidelity virtual reality simulator and an artificial intelligence assessment approach for peg transfer laparoscopic training.

Simulators are widely used in medical education, but objective and automatic assessment is not feasible with low-fidelity simulators, which can be solved with artificial intelligence (AI) and virtual reality (VR) solutions. The effectiveness of a custom-made VR simulator and an AI-based evaluator of a laparoscopic peg transfer exercise was investigated. Sixty medical students were involved in a single-blinded randomised controlled study to compare the VR simulator with the traditional box trainer. A total of 240 peg transfer exercises from the Fundamentals of Laparoscopic Surgery programme were analysed. The experts and AI-based software used the same criteria for evaluation. The algorithm detected pitfalls and measured exercise duration. Skill improvement showed no significant difference between the VR and control groups. The AI-based evaluator exhibited 95% agreement with the manual assessment. The average difference between the exercise durations measured by the two evaluation methods was 2.61 s. The duration of the algorithmic assessment was 59.47 s faster than the manual assessment. The VR simulator was an effective alternative practice compared with the training box simulator. The AI-based evaluation produced similar results compared with the manual assessment, and it could significantly reduce the evaluation time. AI and VR could improve the effectiveness of basic laparoscopic training.

Emerging materials and technologies for advancing bioresorbable surgical meshes.

Surgical meshes play a significant role in the treatment of various medical conditions, such as hernias, pelvic floor issues, guided bone regeneration, and wound healing. To date, commercial surgical meshes are typically made of non-absorbable synthetic polymers, notably polypropylene and polytetrafluoroethylene, which are associated with postoperative complications, such as infections. Biological meshes, based on native tissues, have been employed to overcome such complications, though mechanical strength has been a main disadvantage. The right balance in mechanical and biological performances has been achieved by the advent of bioresorbable meshes. Despite improvements, recurrence of clinical complications associated with surgical meshes raises significant concerns regarding the technical adequacy of current materials and designs, pointing to a crucial need for further development. To this end, current research focuses on the design of meshes capable of biomimicking native tissue and facilitating the healing process without post-operative complications. Researchers are actively investigating advanced bioresorbable materials, both synthetic polymers and natural biopolymers, while also exploring the performance of therapeutic agents, surface modification methods and advanced manufacturing technologies such as 4D printing. This review seeks to evaluate emerging biomaterials and technologies for enhancing the performance and clinical applicability of the next-generation surgical meshes. STATEMENT OF SIGNIFICANCE: In the ever-transforming landscape of regenerative medicine, the embracing of engineered bioabsorbable surgical meshes stands as a key milestone in addressing persistent challenges and complications associated with existing treatments. The urgency to move beyond conventional non-absorbable meshes, fraught with post-surgery complications, emphasises the necessity of using advanced biomaterials for engineered tissue regeneration. This review critically examines the growing field of absorbable surgical meshes, considering their potential to transform clinical practice. By strategically combining mechanical strength with bioresorbable characteristics, these innovative meshes hold the promise of mitigating complications and improving patient outcomes across diverse medical applications. As we navigate the complexities of modern medicine, this exploration of engineered absorbable meshes emerges as a promising approach, offering an overall perspective on biomaterials, technologies, and strategies adopted to redefine the future of surgical meshes.