Determination of anterior femoral bowing to length ratio in Iranian population

Due to the existence of different races and ethnicities and their different life styles, anatomical structure of people vary from one region of the world to another. The goal of this study is to determine the anterior femoral bowing to length ratio, which can be useful for planning major medical and therapeutic projects as well as designing medical equipment (including nails, orthoses and prosthetics). Lateral X-rays of femur bones of 250 patients who referred to Taleghani hospital in recent years (2011-2016) were retrieved from hospital archives and studied. 150 patients were females and 100 were males, ages ranging from 16 to 57 years old. All patients were Iranians with different ethnical backgrounds that referred to radiology centers of Tehran and Taleghani hospital and their records were saved in these centers archive. Based on femoral length, X-rays were categorized into eight groups; 300mm, 320mm, 340mm, 360mm, 380mm, 400mm, 420mm and 440mm, which are standards for manufacturing femoral nails in Iran as well as imported nails to Iran. Results showed significant difference compared to available femoral nails on the Iranian market, which indicates that these nails are not standard for Iranian population. Data analysis was based on anterior femoral bowing to length ratio alone. Gender and age were not considered for data analysis in this study and results were conclusive for all ages and genders

Artificial intelligence investigation of three silicates bioceramics-magnetite bio-nanocomposite: Hyperthermia and biomedical applications

Objective(s): Bioactive silicate ceramics have favorable features for applying as off-the-shelf bone and artificial tissue. Calcium silicate can enhance the generation of an immediate bond with host bone without an intervening rough surface in the bone layer. However, the silicate bioceramics have some drawback regarding their mechanical properties and chemical stabilities. Materials and Methods: In this study, magnetite nanoparticles (MNPs) as reinforcement were added to the three silicate bioceramics to investigate the physical and mechanical properties as well as their magnetic behavior as a case study and compare with other calcium silicate nanocomposite which are excellent candidates for hyperthermia applications. Then the artificial neural network (ANN) applied to the previous data to predict the mechanical and biological behavior of the bio-nanocomposite as output parameters. A predicted model was enhanced using ANN to measure the optimum size and reinforcement amount of the magnetite bio-nanocomposite. The results of the fabricated bio-nanocomposite were extracted experimentally corresponding to different MNPs weight fractions compared to the predicted model. Results: The X-ray diffraction (XRD), scan electron microscopy (SEM) technique were used to compare the porosity and porous tissue microstructure. Thereafter, an analytical solution is presented to express explicitly the physical and mechanical responses of the bulk/scaffold bio-nanocomposite. Conclusion: The obtained results showed the potential application of these calculations and analyses in a wide range of numerical studies. The comparison presented within the test and predicted values showed that the modeling outcomes were close to testing values

Mathematically and experimentally defined porous bone scaffold produced for bone substitute application

Objective (s): Artificial bone implants have been studied as a possible bone replacement for fractured and destroyed facial tissue; the techniques employed to determine the success of the dental implants. The stability, porosity and resistance of the bone implant which is subjected to varying forces and stresses within the surrounding bone is a subject of interest among the dentists. Materials and Methods: An experimental analysis was conducted on bio-nanocomposite scaffold using space holder methods. The reaction of the bio-nanocomposites deformation under load was determined using Abaqus software. Thereafter, an analytical solution was presented to express explicitly the deformation responses of the artificial bone implant. Results: It was seen that the vibrational behavior and mechanical performance of the sample containing 15 wt% additives have shown better mechanical characteristic compared to the pure specimen. On the other hand, the additive weight fraction has a significant effect on the compression test and porosity value. Also, the elastic modulus of the samples increases more than two times with the addition of additive (from 60 MPa to 145 MPa). From the results, it can be concluded that the highest vibration variation is seen in the sample with lower MNPs percentages.Conclusion: By observing the results of the stresses, it was seen that the stresses were in a small value in the bio-nanocomposites with highest amount of reinforcement

Calcium phosphate coatings: morphology, micro-structure and mechanical properties

Many biomedical implant coating systems consist of micro-deposited calcium phosphate droplets thermally sprayed onto a commercially pure Ti (CP Ti) substrate. In this study, the morphology of solidified droplet “splats” was examined using Scanning Electron Microscopy (SEM). The topography of splats sprayed onto substrates at room temperature (25 °C) and preheated to 100 °C and 300 °C was investigated. The splat shape was found to be strongly dependent on substrate preheating temperature. A homogeneous deposit density of amorphous calcium phosphate in splats deposited onto the cold substrate was confirmed by micro-Raman spectroscopy, whereas a very early stage of re-crystallization was detected using Transmission Electron Microscopy (TEM) for splats deposited onto 300 °C preheated substrates. TEM in conjunction with Focused Ion Beam (FIB) revealed the splats' ultra micro-structure. Correlation of Atomic Force Microscopy (AFM) with these results enabled links between different types of micro structures and true splat contacts with the substrates to be shown. Splats deposited onto the substrate at 300 °C showed generally well-adherent interfaces. The established presence of a thin layer of native oxide on this polished and preheated surface could serve to enhance the splat-substrate adhesion. Nano-indentation revealed that splats deposited onto the substrates at room temperature and 100 °C have similar hardness and elastic modulus values; however, preheating the substrate up to 300 °C improved these micro-mechanical properties. These combined findings promote further understanding of the extrinsic properties of the bulk calcium phosphate coating

Micro-Raman Spectroscopy Shows How the Coating Process Affects the Characteristics of Hydroxylapatite

The diversity in the structural and chemical state of apatites allows implant manufacturers to fine-tune implant properties. This requires suitable manufacturing processes and characterization tools to adjust the amorphous phase and hydroxyl content from the source hydroxylapatite. Hydroxylapatite was processed by high-velocity oxy-fuel spraying, plasma spraying and flame spraying, and primarily analyzed by Raman spectroscopy. Investigation of rounded splats, the building blocks of thermal spray coatings, allowed correlation between the visual identity of the splat surface and the Raman spectra. Splats were heat-treated to crystallize any remaining amorphous phase. The ν1 PO4 stretching peak at 950-970 cm-1 displayed the crystalline order, but the hydroxyl peak at 3572 cm-1 followed the degree of dehydroxylation. Hydroxyl loss was greatest for flame-sprayed particles, which create the longest residence time for the melted particle. Higher-frequency hydroxyl peaks in flame- and plasma-sprayed splats indicated a lower structural order for the recrystallized hydroxylapatite within the splats. Crystallization at 700 C has shown potential for revealing hydroxyl ions previously trapped in amorphous calcium phosphate. This work compares Fourier transform infrared and Raman spectroscopy to measure the hydroxyl content in rapidly solidified apatites and shows that Raman spectroscopy is more suitable

The use of thermal printing to control the properties of calcium phosphate deposits

The objective of this work was to characterize the deposits of calcium phosphate produced by thermal printing in terms of structure, topography and mechanical properties. Hydroxyapatite was molten and directed to (a) a titanium target in relative motion and (b) stationary titanium substrates preheated to 100 °C and 350 °C. Scanning electron microscopy showed round-like deposits, but high resolution profilometry measured the profile. Micro-Raman spectroscopy and X-ray diffraction characterized the surface for structure, while nanoindentation revealed the hardness and elastic modulus. A symmetrical hemispherical deposit was formed on a surface in slow relative motion, but an off-centre shape formed at a higher relative speed. Deposits on preheated surfaces (100 °C and 350 °C) were identified as amorphous calcium phosphate. Nanoindentation revealed no significant difference in hardness between the amorphous deposits (4.0–4.4 ± 0.3 GPa), but the elastic modulus increased from 65 ± 4 GPa (annealed calcium phosphate reference) to 88 ± 3 GPa (100 °C surface) and then to 98 ± 3 GPa (350 °C substrate). The large change in elastic modulus is thought to arise from the dehydroxylation during thermal printing. Production of functional materials through crystallization is discussed to extend the range of possible microstructures. The characterization and testing approach is useful for hemispherical deposits produced by printing, coatings (laser ablation, thermal spraying, simulated body fluid) and melt extrusion elements in scaffolds

Effect of angled indentation on mechanical properties

Indentation on a smooth surface, perpendicular to the indenter tip, is critical to obtaining accurate mechanical property values with nanoindentation. However, for some materials, achieving such a scenario may not always be feasible. To investigate the effect this may have, angled indentations were made on flat, sintered hydroxyapatite samples individually mounted so as to produce indentation angles of 10°, 20°, 30°, 40° and 50°, as well as leading contact with either the face or edge of the Berkovich tip used. While significant scatter in results reinforced the importance of perpendicular penetration, two phenomena were found to serve as potential indicators of angled indentation, and hence unreliable data. It is recommended that topographical profiles are obtained on any material of uncertain roughness prior to indentation

Revealing mechanical properties of a suspension plasma sprayed coating with nanoindentation

Solution and suspension thermal spraying is providing a more economic approach to the production of thin coatings. Advances in this new promising technology require accompanying tools to assess micro and nanosized areas within these deposits. Hydroxyapatite was deposited in an r.f. plasma using a powder and a suspension. The powder feedstock produced a dense, oriented coating, whereas the suspension led to a porous randomly oriented coating. The porosity leads to a decrease in the hardness and elastic modulus of the bulk coating, but site specific indentations on dense areas in the SPS coating revealed greater values (5 ± 0.2 vs 4 ± 0.2 GPa), possibly due to the finer grain size and crystal orientation. Nanoindentation presents a valuable tool for the assessment of the mechanical properties in solid areas of porous materials, and when used with microscopy will be valuable for the further development of SPS coatings