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The honeycomb pattern possesses a distinctive hexagonal structure capable of seamless repetition on a flat surface, leaving no gaps. Moreover, all arm thicknesses and angles are equal to one another. This remarkable configuration is deemed biomimetic, with numerous examples found in nature. Notably, it exhibits remarkably low density and exceptional mechanical strength. MAX phase films have gathered significant attention due to their exceptional capacity to amalgamate the essential properties of both metals and ceramics. Additionally, they possess the unique ability to effectively mend surface cracks that may arise as a result of friction-wear, restoring the material to a certain degree of integrity. In this study, Ti2AlN MAX phase thin films were deposited on M2 steel substrates by a closed field unbalanced magnetron sputtering system (CFUBMS). 750 °C heat treatment was applied to obtain the produced films in crystalline form. In addition, plasma etching parameters suitable for the phase structure of the deposited film were determined. With the inductive coupling plasma etching (ICP) process, the honeycomb pattern was given to the Ti2AlN MAX phase films with a continuous and smooth geometry at a depth of 2 μm. This study gives ideas for the development of multi-coating systems in which patterns of different geometries are included in a single layer. [ABSTRACT FROM AUTHOR]

Conventional fixation plates permanently attached to the body can lead to complications, such as stress shielding and aseptic loosening, due to their contact with the bone, resulting in bone loss. The contact between these solid fixation plates and the bone surface inhibits blood flow, potentially leading to necrosis at the interface. To overcome this challenge, a porous implant featuring a gyroid lattice structure for humerus bone fixation is proposed. However, designing such an implant typically involves deterministic approaches, which do not account for uncertainties in design parameters, loadings on the plate, and additive manufacturing process parameters. Consequently, the actual conditions experienced by the plate may not be accurately modeled. Herein, both deterministic and probabilistic analyses of a porous implant with a gyroid lattice structure positioned on the humeral bone is conducted. The findings are compared to the failure probabilities of both the conventional fixation plate and the optimal plate derived from a previous study. The study reveals that uncertainties in design parameters significantly influence the plate's failure probability compared to deterministic analysis, emphasizing the importance of probability‐based analyses for a reliable plate design. [ABSTRACT FROM AUTHOR]

We aimed to evaluate the trueness of digital and conventional impression techniques based on different angles and distances between implants and the deviation caused by the angle and distance parameters varying between implants. Eight implants were placed in a polyurethane edentulous mandibular model at different angles and distances. After obtaining a 3-dimensional (3D) reference model by using an optical scanner, the model was scanned with three intraoral scanners: Cerec Omnicam (DO), Trios 3 (DT), and Carestream 3500 (DC). Then, the master casts obtained from the conventional impressions (C) were also digitized, and all impression data were imported into reverse engineering software to be compared with the 3D reference model. Distance and angle measurements between adjacent implants were performed, and the data were analyzed with ANOVA–Tukey and Kruskal Wallis tests. The significance level was accepted as p < 0.05. While DT and C groups gave the best results for high interimplant distances, the trueness of intraoral scanners was found to be superior to the conventional method between closer implants. At higher angulations, the angular trueness of C group was found to be significantly lower. At short distances, digital groups showed superiority, and the trueness of conventional impression decreased with higher angulations. [ABSTRACT FROM AUTHOR]

Modeling of ligament tissues in computer simulations in biomechanics is important for achieving the simulation anatomically. These are often described as hyperelastic materials in these types of studies. However, in order to be defined as a hyperelastic material, a mathematical material model created with data obtained from tests such as tension, compression, and creep is needed. There are many phenomenological models that can be used as material models. In this study, ligament tissue simulation was created according to Neo-Hookean, Ogden 2nd Order and Yeoh 2nd Order hyperelastic material models. In-vitro uniaxial tensile testing of sheep anterior cruciate ligament was performed for data on the stressstrain curve to be used by the models. According to the data obtained from the tensile test, the material constants required for the material models were calculated. As a result of the analysis, it was determined that Ogden 2nd Order and Yeoh 2nd Order models were close results and Neo-Hookean model gave results with different stress values. The fit of the stress-strain curves obtained from three models and in-vitro test was evaluated according to the Root Mean Square Error(RMSE) values. RMSE values of Neo-Hookean, Ogden 2nd Order and Yeoh 2nd Order hyperelastic material models were obtained as 4.9597, 1.9704 and 2.3644, respectively. As a result, the Ogden 2nd Order hyperelastic material model with a high number of material constants produced results closer to in-vitro test results compared to both normal and von-mises stress values and RMSE values. Among the three models analyzed for simulations of ligament tissue, it was determined that the use of this material model was more appropriate. [ABSTRACT FROM AUTHOR]

Purpose: The accuracy of digital impressions is still controversial for complete arch implant cases. The aim of this study is to compare the accuracy of different intraoral scanners with the conventional technique in terms of trueness and precision in a complete arch implant model. Material and Methods: Eight implants were inserted asymmetrically in a polyurethane edentulous mandibular model with different angulations. A 3‐dimensional (3D) reference model was obtained by scanning this polyurethane model with an optical scanner. First, digital impressions were made by using 3 different intraoral scanners: Carestream 3500 (DC), Cerec Omnicam (DO) and 3Shape Trios 3 (DT). Subsequently, a nonsplinted open tray impression technique was used for conventional impression group (C) and then the master casts were digitalized with a lab scanner. Each 10 STL files belonging to 4 different impression groups were imported to a reverse engineering program, to measure distance and angle deviations from the reference model. All statistical analyses were performed after taking absolute values of the data. After comparing the impression groups with one‐way ANOVA, the trueness and precision values were analyzed by Tukey post hoc test and 0.05 was used as the level of significance. Results: The mean trueness of distance was 123.06 ± 89.83 µm for DC, 229.72 ± 121.34 µm for DO, 209.75 ± 47.07 µm for DT, and 345.32 ± 75.12 µm for C group (p < 0.0001). While DC showed significantly lower deviation compared to DO and C, no significant difference was found between DC and DT. C showed the highest distance deviation significantly in all groups; and no significant difference was found between DO and DT groups. In angle measurements; the trueness was 0.26° ± 0.07° for DC, 0.53° ± 0.42° for DO, 0.33° ± 0.30° for DT, and 0.74° ± 0.65° for C group. There was no significant difference between the groups in terms of angular trueness (p = 0.074). In terms of the precision for distance, the results of DC 80.43 ± 29.69 µm, DO 94.06 ± 69.96 µm, DT 35.55 ± 28.46 µm and C 66.97 ± 36.69 µm were determined (p = 0.036). The significant difference was found only between DT and DO among all groups. Finally, angular precision was determined to be 0.19° ± 0.11° for DC, 0.30° ± 0.28° for DO, 0.22° ± 0.19° for DT, and 0.50° ± 0.38° for Group C. No significant difference was found between the groups, in terms of angular precision (p = 0.053). Conclusions: All digital impression groups yielded superior data compared to conventional technique in terms of trueness. DC formed the impression group with the highest trueness in both distance and angular measurements. The results of this in vitro study suggest the use of intraoral scanners compared to the conventional impression techniques in complete arch implant cases with high angulations. [ABSTRACT FROM AUTHOR]

Total Knee Arthroplasty (TKA) treatment has been widely used for knee joint, having the most complex motion sequences and shape of the body, in case of loss of motion ability such as gonarthrosis. Lots of failures such as loosening, wear and instability have occurred as a result of increasing usage period. Instability is the most commonly seen failure associated with fixation. Especially loosening of tibial component is more common than that of femoral component. Evaluation of bone in terms of shape related with patient's weight, height and gender is required to increase the success of TKAs comprising traditional tibial components. Most of the current commercially available knee prostheses are designed based on the anthropometric data of Caucasian knees. This means an accordance problem for the people in different regions having different joint size. In this study, a patient specific tibial component has been designed according to cutting surface of tibial bone obtained from the patient's computed tomography images. This proposed design has been comparatively investigated with the traditional cemented tibial component by using the finite element analysis. In conclusion, more uniform stress distribution on the tibial trabecular bone related with stress shielding due to long term use was obtained in the patient specific prosthesis. The results have shown that the compatibility between the tibial bone and its component is better than the traditional model and possibility of loosening failure in the patient specific model is lower. [ABSTRACT FROM AUTHOR]