NO SIGNIFICANT EFFECT OF 3D MODELLING ON SURGICAL PLANNING IN SPINAL DEFORMITIES.

Objective: To evaluate the effect of 3d printed models on surgical pre-operative planning of complex spinal deformities. Methods: In our study, five orthopedic surgeons made surgical planning of 5 patients with severe spinal deformity in three conditions: X-ray with computer tomography (X-ray-CT), 3D-computed tomography (3dCT), and 3d printed spine models. Operation plans were examined according to the level and number of instrumentations, osteotomy level, and time required for decision-making. Results: X-ray-CT, 3dCT, and 3d modeling methods were compared, and no statistically significant difference was observed in the number of screws and osteotomy score to be used in operation. The time required for decision ranking is 3d Model, 3d CT, and Xray-CT. Conclusions: 3d printed models do not influence the operative plan significantly; however, it reduces surgical planning time at pre-op duration, and those models gave some opportunities to practice with implants on a patient's 3d spine model. Level of Evidence III; Diagnostic Studies - Investigating a Diagnostic Test .

Objetivo: Avaliar o efeito de modelos 3D impressos no planejamento pré-operatório cirúrgico de deformidades complexas da coluna vertebral. Métodos: Em nosso estudo, 5 cirurgiões ortopédicos fizeram o planejamento cirúrgico de 5 pacientes com deformidade espinhal grave em três condições: raio-X com tomografia computadorizada (raio X-CT), tomografia computadorizada com reconstrução 3D (3dCT) e modelo de coluna vertebral impressa (modelo 3d). Os planos de operação foram examinados de acordo com o nível e número de instrumentos, nível de osteotomia e tempo necessário para a tomada de decisão. Resultados: Foram comparados os métodos de modelagem de raio X-CT, 3dCT e modelo 3d e nenhuma diferença estatisticamente significativa foi observada no número de parafusos e escore de osteotomia a serem utilizados na operação. O ranking do tempo necessário para a tomada de decisão foi de modelo 3d, 3d CT e raio X-CT. Conclusões: Os modelos impressos em 3d não influenciam significativamente o plano operatório, porém reduzem o tempo de planejamento cirúrgico no pré-operatório e esses modelos deram algumas oportunidades de praticar com implantes no modelo de coluna 3d do paciente. Nível de evidência III; Estudos de Diagnóstico - Investigando um Teste de Diagnóstico .

Investigation of antimicrobial and mechanical effects of functional nanoparticles in novel dental resin composites.

OBJECTIVES: Imidazole and benzimidazole derivatives have recently attracted attention as remarkable materials due to their advantages in chemistry, pharmacology, and biomaterials. This article focuses on dental composites with azole functional groups incorporated to affect their physicochemical and mechanical properties and antibacterial activity. METHODS: Dental composites were fabricated by embedding the functionalized imidazole and benzimidazole nanoparticles into a Bis-GMA/TEGDMA matrix to form the imidazole and benzimidazole dental composites series (I and B). The material was produced through hand blending of the monomer (50:50, wt%), filler (0-30, wt%), and initiator combination (CQ/EDMAB:0.8:1.6, wt%), and LED light-curing unit for 60 s. RESULTS: Using various characterization techniques, I and B series were validated. The dental composites' approximate solubility and sorption significances were evaluated by conducting experiments on specific dental composite formulations. Fenton reaction test was performed to determine the chemical stability of the dental composites. The mechanical properties of the dental composites were investigated. Finally, by testing cell growth in the presence of composites, their antibacterial activities were determined. CONCLUSIONS: In this study, it was observed that the mechanical, physiochemical, and antibacterial properties of the functional azole-containing nanoparticles were positively improved by adding them to the structure of dental composites. These experimental results paved the way for the synthesized materials to be used in industrial applications. CLINICAL SIGNIFICANCE: Since the chemical, mechanical, and antimicrobial properties of dental composites containing 10% imidazole and benzimidazole functional nanoparticles are far superior, they constitute an excellent alternative for preventing dental caries and long-term use of dental composites.

Recombinant Activated Protein C (rhAPC) Affects Lipopolysaccharide-Induced Mechanical Compliance Changes and Beat Frequency of mESC-Derived Cardiomyocyte Monolayers.

BACKGROUND: Septic cardiomyopathy increases mortality by 70% to 90% and results in mechanical dysfunction of cells. METHODS: Here, we created a LPS-induced in-vitro sepsis model with mouse embryonic stem cell-derived cardiomyocytes (mESC-CM) using the CellDrum technology which simultaneously measures mechanical compliance and beat frequency of mESCs. Visualization of reactive oxygen species (ROS), actin stress fibers, and mRNA quantification of endothelial protein C receptor (EPCR) and protease-activated receptor 1 (PAR1) before/after LPS incubation were used for method validation. Since activated protein C (APC) has cardioprotective effects, samples were treated with human recombinant APC (rhAPC) with/-out LPS predamage to demonstrate the application in therapeutic studies. RESULTS: Twelve hours LPS treatment (5 µg/mL) increased ROS and decreased actin stress fiber density and significantly downregulated EPCR and PAR1 compared to control samples (0.26, 0.39-fold respectively). rhAPC application (5 µg/mL, 12 h) decreased ROS and recovered actin density, EPCR, and PAR1 levels were significantly upregulated compared to LPS predamaged samples (4.79, 3.49-fold respectively). The beat frequencies were significantly decreased after 6- (86%) and 12 h (73%) of LPS application. Mechanical compliance of monolayers significantly increased in a time-dependent manner, up to eight times upon 12-h LPS incubation compared to controls. rhAPC incubation increased the beat frequency by 127% (6h-LPS) and 123% (12h-LPS) and decreased mechanical compliance by 68% (12h-LPS) compared to LPS predamaged samples. CONCLUSION: LPS-induced contraction dysfunction and the reversal effects of rhAPC were successfully assessed by the mechanical properties of mESC-CMs. The CellDrum technology proved a decent tool to simulate sepsis in-vitro.

No significant effect of 3d modelling on surgical planning in spinal deformities / Nenhum efeito significativo da modelagem 3d no planejamento cirúrgico em deformidades da coluna vertebral

ABSTRACT Objective: To evaluate the effect of 3d printed models on surgical pre-operative planning of complex spinal deformities. Methods: In our study, five orthopedic surgeons made surgical planning of 5 patients with severe spinal deformity in three conditions: X-ray with computer tomography (X-ray-CT), 3D-computed tomography (3dCT), and 3d printed spine models. Operation plans were examined according to the level and number of instrumentations, osteotomy level, and time required for decision-making. Results: X-ray-CT, 3dCT, and 3d modeling methods were compared, and no statistically significant difference was observed in the number of screws and osteotomy score to be used in operation. The time required for decision ranking is 3d Model, 3d CT, and Xray-CT. Conclusions: 3d printed models do not influence the operative plan significantly; however, it reduces surgical planning time at pre-op duration, and those models gave some opportunities to practice with implants on a patient's 3d spine model. Level of Evidence III; Diagnostic Studies - Investigating a Diagnostic Test .

RESUMO Objetivo: Avaliar o efeito de modelos 3D impressos no planejamento pré-operatório cirúrgico de deformidades complexas da coluna vertebral. Métodos: Em nosso estudo, 5 cirurgiões ortopédicos fizeram o planejamento cirúrgico de 5 pacientes com deformidade espinhal grave em três condições: raio-X com tomografia computadorizada (raio X-CT), tomografia computadorizada com reconstrução 3D (3dCT) e modelo de coluna vertebral impressa (modelo 3d). Os planos de operação foram examinados de acordo com o nível e número de instrumentos, nível de osteotomia e tempo necessário para a tomada de decisão. Resultados: Foram comparados os métodos de modelagem de raio X-CT, 3dCT e modelo 3d e nenhuma diferença estatisticamente significativa foi observada no número de parafusos e escore de osteotomia a serem utilizados na operação. O ranking do tempo necessário para a tomada de decisão foi de modelo 3d, 3d CT e raio X-CT. Conclusões: Os modelos impressos em 3d não influenciam significativamente o plano operatório, porém reduzem o tempo de planejamento cirúrgico no pré-operatório e esses modelos deram algumas oportunidades de praticar com implantes no modelo de coluna 3d do paciente. Nível de evidência III; Estudos de Diagnóstico - Investigando um Teste de Diagnóstico .

Clinical trials of 3D printing splints to avoid contracture development in burned children

Background/aim: We evaluated the feasibility of producing splints with 3D printer technology to prevent contractures in burned children in our clinical prospective study. Materials and methods: After approvals, children with burns greater than 2nd degree were included in the study. Age, sex, burn percentages, printing time, filament types, number of filament trials, splint suitability, patient and doctor comments, preclinical trials' significances and financial impact were evaluated statistically. Results: Seventy-six trials were conducted on 18 patients. Fourteen of the patients were male and 4 are female. Average ages of boys and girls were 5 and 3, respectively. Burn percentage was 36.9 ± 13. Polylactic acid (PLAFlex), polyurethane (PolyFlex), semiflexible copolyester (nGenFlex), and thermoplastic polyurethane (TPU) were the main filaments that were used in the study. Printing time differed from 4 to 29 h according to body regions. Splints were suitable for 81.25% in upper extremity, for 66.7% in lower extremity, and for 100% in mouth. Burn percentage was significantly correlated with total number of filament (p = 0.049). Other statistical evaluations were insignificant. Conclusion: The 3D printer seems to be useful in children with burns. However, difficulties caused by some reasons like production must be overcome. By increasing clinical experience, this emerging custom-made technology may become standard, and documented problems can be solved.

Comparative study of biomechanical stability of resorbable and titanium fixation systems after sagittal split ramus osteotomy with a novel designed in-vitro testing unit.

INTRODUCTION: Sagittal split ramus osteotomy (SSRO) is one of the most popular surgical procedures for correction of mandibular deformities. Several clinical and biomechanical studies exist in the literature which, comparing the stability of different osteosynthesis materials and techniques, were performed using two or three-point biomechanical test models. The aim of this study was to compare the stability of biodegradable and titanium materials for SSRO on one-piece polyurethane mandible samples which were fixed in a novel designed 6-point testing unit. MATERIALS AND METHODS: 16 polyurethane one piece replicas of human mandibles were used and bilateral SSRO were performed by the manufacturer according to Dal Pont modification. Mandibles were fixed with titanium and PLLA/PGA fixation materials. Displacement amounts were measured under loading forces using a non-contact extensometer, and strain values at the screws were recorded by strain gauges. RESULTS: Bicortical titanium screws (Group 2) showed significantly lower displacement values, while bicortical PLLA/PGA screws (group 4) showed significantly higher displacement values at 40-360 N forces. (p < 0.05). The highest strain value was measured on screws that were inserted upright in a proximal segment near the osteotomy line. CONCLUSION: To achieve more realistic results in biomechanical studies, test models should imitate jaw movements and test environments should be as similar as possible to physiological conditions. Newly designed six-point testing units will contribute to future biomechanical studies.

Development of a 2-dof uterine manipulator with LED illumination system as a new transvaginal uterus amputation device for gynecological surgeries.

BACKGROUND: Hysterectomy, the most common major gynecological operation worldwide, consists of removal of the uterus and can be performed abdominally, vaginally, or laparoscopically. A uterine manipulator is a key device used for uterine manipulation and cannulation in hysterectomies. The challenges of conventional manipulators are to move the uterus in two distinct planes and to identify cervical landmarks during circular cut and coagulation. MATERIAL AND METHODS: In this study, a structural synthesis of the two degrees of freedom parallel manipulator was performed considering the constraints noted by surgeons. Computer-aided design and assembly of the manipulator, the cervicovaginal cap with LEDs, and the external parts were performed before rapid prototyping. The final design of the uterine manipulator was then manufactured from stainless steel and tested on an artificial uterus model using a test chamber. RESULTS: This article presents the design, production and testing processes of an innovative manipulator with a motion capability up to 80° workspace both in the sagittal and coronal planes and an illumination system, easily detectable by the laparoscope, was successfully implemented on the manipulator's cervical cap in order to overcome the drawbacks of conventional uterine manipulators. CONCLUSIONS: Despite all the current studies and uterine manipulators on the market, no research has incorporated all the features mentioned above.

Three-dimensional finite element analysis of stress distribution of two-retainer and single-retainer all-ceramic resin-bonded fixed partial dentures.

OBJECTIVE: A long-term clinical study previously stated that adhesively luted resin-bonded fixed partial dentures (RBFPDs) with two retainers exhibited two complications (loss of adhesion or fracture between retainer and pontic) when compared to RBFPDs with a single retainer. The reasons for these complications were not reported. The aim of this study was to evaluate the stress distribution of two-retainer and singleretainer zirconium dioxide RBFPDs by using three-dimensional finite element analysis (3D FEA). METHOD AND MATERIALS: Two different 3D finite element models were created. Each model contained cortical bone, cancellous bone, periodontal ligament, cement, and enamel. Additionally one of the models contained a two-retainer zirconium dioxide RBFPD while another contained a single-retainer zirconium dioxide RBFPD. A 100 N force was applied at 45 degrees 2 mm below the incisal edge of the palatal surface of the pontic. In each model, Von Mises stress distribution was evaluated. RESULTS: Maximum Von Mises stress values in RBFPD with a single retainer and two retainers were 1.13 MPa and 1.23 MPa, respectively. Von Mises stress was concentrated at the interface between pontic and retainer for RBFPD with two retainers. CONCLUSION: Zirconium dioxide RBFPD with a single retainer and two retainers exhibited similar stress concentrations between pontic and retainer. However, the use of a single retainer for RBFPDs prevented stress concentration at the interface between retainer and pontic.

A new medical device to measure a stiffness of soft materials.

An objective in vivo measurement technique for assessing the material properties of soft tissue would be a valuabe tool in diagnosing dermatological pathologies. In order to make advancements in this field, a new hand-held device was designed to measure the stiffness of soft materials. The device measures the reaction forces experienced by the soft tissue under constant indentation deformations at the time of stiffness measurement. Agarose gel samples were prepared in a range of molarities to mimic the stiffness variabilities found in vivo. The stiffness of each gel was evaluated using two different measurement techniques. The first method utilized an industry standard durometer, designed to measure the hardness of materials in shore type 00 scales of soft plastics. The second measurement was taken using an original custom-built soft tissue stiffness meter, designed specifically for the present study. These two devices were compared and a strong correlation was found between them (r²=1.00, Spearman rank test). Additionally, it was observed that gels of different stiffness could be distinguished by both devices. In conclusion, the soft tissue stiffness can be accurately evaluated using the proposed device. The new device should be evaluated on human subjects in future studies, before it can be used to assess soft tissue disorders.

Optical coherence tomography: a potential tool to predict premature rupture of fetal membranes.

A fundamental question addressed in this study was the feasibility of preterm birth prediction based on a noncontact investigation of fetal membranes in situ. Although the phenomena of preterm birth and the premature rupture of the fetal membrane are well known, currently, there are no diagnostic tools for their prediction. The aim of this study was to assess whether optical coherence tomography could be used for clinical investigations of high-risk pregnancies. The thickness of fetal membranes was measured in parallel by optical coherence tomography and histological techniques for the following types of birth: normal births, preterm births without premature ruptures and births at full term with premature rupture of membrane. Our study revealed that the membrane thickness correlates with the birth type. Normal births membranes were statistically significantly thicker than those belonging to the other two groups. Thus, in spite of almost equal duration of gestation of the normal births and the births at full term with premature rupture, the corresponding membrane thicknesses differed. This difference is possibly related to previously reported water accumulation in the membranes. The optical coherence tomography results were encouraging, suggesting that this technology could be used in future to predict and distinguish between different kinds of births.