EFFECT OF TiO2 ADDITION ON BONDING STRENGTH OF CaO-P2O5 Na2O-TiO2 BIOACTIVE GLASS CERAMIC COATING

The effect of titanium dioxide addition on bonding strength of CaO-P2O5 -Na 2O-TiO2glass-ceramic system was investigated as a coating on titanium substrate. Thus, different amounts of TiO2 (2, 3.5 and 5mol %) were added to the base glass batch composition. The prepared glaze slips were applied on the substrate by dip coating method, dried and then heat treated at various temperatures. After that, bonding strength of the glass- substrates was determined via shear stress testing method. The de-bonded interfaces were analyzed by scanning electron microscopy (SEM). According to these results, the 5 mol% TiO 2 containing coating showed the best bonding strength, comparing with the other coatings. The bioactivity of the coated samples was investigated by soaking them in simulated body fluid (SBF). The surface of the samples was studied using SEM and X-Ray microprobe and it was observed that an apatite layer was grown on their surfac

Effect of P2O5 on Crystallization Behavior and Chemical Resistance of Dental Glasses in the Li2O-SiO2-ZrO2 System

Commercial dental lithium disilicate based glass-ceramics containing various amounts of P2O5 were synthesized. Regarding the crystallization behavior and physico-chemical properties of the glasses, the optimum percent of P2O5 was determined.as 8 %wt. Crystallization behavior of the glasses was investigated by X-ray diffraction (XRD) and differential thermal analysis (DTA). The micro-hardness and chemical resistance of both glass and glass-ceramic searies were also determined. According to our results, lithium phosphate was precipitated prior to crystallization of the main phases, i.e lithium meta silicate and lithium disilicate. This early precipitation led to evacuation of residual glass phase from lithium ions, which caused increasing the viscosity of glass and so shifting of crystallization to higher temperatures. In addition, increasing in P2O5 amounts and consequently increasing in Li3PO4, led to significant decrease in the crystallite size and aspect ratio  of crystals. Furthermore, while the chemical resistance of the glasses was decreased with P2O5, it was increased with P2O5 after heat treatment process. The chemical solubility of these three glass-ceramics was between 2080~1188 μg/cm2

Hydrothermal Synthesis of Cobalt- Doped Hydroxyapatite Nanoparticles: Structure, Magnetic Behaviour, Bioactivity and Antibacterial Activity

This study focuses on the physical, magnetic, biological and antibacterial behaviour of cobalt-doped HAp powder samples. Pure and Cobalt- doped HAp nanoparticles were synthesized by hydrothermal method. Calcium nitrate, di- ammonium hydrogen phosphate and cobalt nitrate were used as precursor materials.  The synthesized powders were characterized using x-ray diffraction pattern (XRD), fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), vibrating sample magnetometer (VSM), Raman spectroscopy as well as MTT assay and cell adhesion test. Disc diffusion method was used to investigate antibacterial activity of the samples. The results confirmed the substitution of Ca by Co ions in the HAp lattice. In addition, this substitution induced size reduction and morphology change in HAp particles. All cobalt substituted HAp powder samples displayed paramagnetic properties, as opposed to the diamagnetic behaviour observed in the pure HAp samples. In addition, these nanoparticles exhibited cell adhesion, biocompatibility and antibacterial activity against S.aureus bacteria. This study focuses on the physical, magnetic, biological and antibacterial behaviour of cobalt-doped HAp powder samples. Pure and Cobalt- doped HAp nanoparticles were synthesized by hydrothermal method. Calcium nitrate, di- ammonium hydrogen phosphate and cobalt nitrate were used as precursor materials.  The synthesized powders were characterized using x-ray diffraction pattern (XRD), fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), vibrating sample magnetometer (VSM), Raman spectroscopy as well as MTT assay and cell adhesion test. Disc diffusion method was used to investigate antibacterial activity of the samples. The results confirmed the substitution of Ca by Co ions in the HAp lattice. In addition, this substitution induced size reduction and morphology change in HAp particles. All cobalt substituted HAp powder samples displayed paramagnetic properties, as opposed to the diamagnetic behaviour observed in the pure HAp samples. In addition, these nanoparticles exhibited cell adhesion, biocompatibility and antibacterial activity against S.aureus bacteria

Sol–gel preparation and characterization of nano-crystalline lithium–mica glass–ceramic

The nano-crystalline lithium–mica glass–ceramic with separated crystallite size of 13 nm was prepared using sol–gel technique. In such a process, the structural evolutions and microstructural characteristics of the synthesized samples were investigated through X-ray diffraction, transmission electron microscopy, thermal analysis and Fourier transform infrared spectroscopy. It was found that the crystallite size of the mica obtained from sol–gel method is smaller than the one synthesized via conventional melted method. The XRD results also showed that the crystallization of mica occurred above 675 °C and it could originate from MgF2 so that the next stage will also be the transformation from mica to norbergite and norbergite to chondrodite. The activation energy of the crystallization and Avrami factor were measured as 376.7 kJ mol−1 and 2.3, respectively. It is found that the bulk crystallization could be considered as the predominant crystallization mechanism for the glass–ceramic

Evaluation of Cyproheptadine Hydrochloride Effects on Weight Gain in Underweight Children with Anorexia; A Randomized Clinical Trial

Background: Cyproheptadine hydrochloride is an antihistaminic drug. Appetite stimulation is one of its secondary effects that can be of advantage in some diseases. In this study we investigated the effect of Cyproheptadine hydrochloride on weight gain in underweight children with anorexia at age group 2 to10 years old. Materials and Methods: In this randomized clinical trial, we selected 2-10 year-old underweight children with anorexia who referred to Ayatollah Mousavi Hospital in Zanjan (Iran), during 2015. One hundred and thirty-six children were allocated at random in two groups. The Cyproheptadine - treated children group were given the drug orally; 0.1 mg/kg/dose three times per day for 8 weeks, while patients in placebo group received placebo with the same dose. After two months, weight gain was compared with the previous values in both groups. Results: In this study, 86 patients (63.2%) were female. The average increase in weight in the cyproheptadine - treated group was significantly higher than in the placebo group (1.08 ± 0.67 kg and 0.22 ± 0.46 kg, respectively) (p=0.005). The average increase height in the Cyproheptadine -treated group was significantly higher than in the placebo group (1.60 ± 0.97 cm, and 0.86 ± 0.85 cm, respectively) (p=0.005). According to the parents of both groups, anorexia in the Cyproheptadine -treated group improved in 100%, and in the placebo group in 52.7%. This difference was statistically significant (p=0.005). No any side effects of Cyproheptadine hydrochloride were observed. Conclusion: According to the finding of our study, there were no serious side effects of Cyproheptadine hydrochloride. Therefore considering the acceptable safety of Cyproheptadine hydrochloride for inducing growth in underweight children, we propose its administration with the aforementioned dose

Behavior of Yb3+ and Er3+ during Heat Treatment in Oxyfluoride Glass Ceramics

The effects of alumina content and heat treatment on upconversion properties of codoped (ErF3-YbF3) oxyfluoride glass ceramics were investigated. Results showed that alumina content had an effect on phase separation and viscosity of the glass. Due to the high viscosity of low alumina content glass, the phase separated areas were smaller in these specimens. Increasing the heat treatment temperature led to the incorporation of Er3+ ions into CaF2 crystals and also increased the Yb3+ concentration in them. This increase improved the energy transfer and back transfer process between Er3+ and Yb3+ ions and as result upconversion intensity was increased

Enhancing Mechanical Properties and Biological Performances of Injectable Bioactive Glass by Gelatin and Chitosan for Bone Small Defect Repair

Bioactive glass (BG) represents a promising biomaterial for bone healing; here injectable BG pastes biological properties were improved by the addition of gelatin or chitosan, as well as mechanical resistance was enhanced by adding 10 or 20 wt% 3-Glycidyloxypropyl trimethoxysilane (GPTMS) cross-linker. Composite pastes exhibited bioactivity as apatite formation was observed by Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) after 14 days immersion in simulated body fluid (SBF); moreover, polymers did not enhance degradability as weight loss was >10% after 30 days in physiological conditions. BG-gelatin-20 wt% GPTMS composites demonstrated the highest compressive strength (4.8 ± 0.5 MPa) in comparison with the bulk control paste made of 100% BG in water (1.9 ± 0.1 MPa). Cytocompatibility was demonstrated towards human mesenchymal stem cells (hMSC), osteoblasts progenitors, and endothelial cells. The presence of 20 wt% GPTMS conferred antibacterial properties thus inhibiting the joint pathogens Staphylococcus aureus and Staphylococcus epidermidis infection. Finally, hMSC osteogenesis was successfully supported in a 3D model as demonstrated by alkaline phosphatase release and osteogenic genes expression