Calcium PHOSPHATE cements (CPCs), using B-TRICALCIUM PHOSPHATE (ß-TCP, Ca3 (P04)2), dicalcium PHOSPHATE (DCP, CaHP04), calcium carbonate (Ca CO3), and hydroxylapatite (HAp, Ca10(P04)6(OH)2) as powder cement and disodium hydrogen PHOSPHATE (Na2HP04) solution as liquid component were prepared. After mixing the powder and liquid constituents, injectable and self-setting calcium PHOSPHATE cements (CPCs) were prepared with different liquid to powder ratios (UP) that formed hydroxylapatite and ß-TRICALCIUM PHOSPHATE as the only end products, which were characterized by FTIR, XRD and SEM techniques. The results showed that, at certain concentration of Na2HP04 (6 wt%), the initial and final setting times decreased by decreasing the UP ratio.

Objective: The aim of this study was to investigate the mechanical properties (flexural strength, micro-shear bond strength) and remineralizing potential of fissure sealants by adding various concentrations of b-TRICALCIUM PHOSPHATE NANOPARTICLES.Materials and Methods: This in-vitro study consisted of five experimental groups containing prepared nano-fisssure sealants (1-5 wt.% b-TCP NANOPARTICLES) and two control groups containing a prepared and a commercial fissure sealant.Flexural/micro-shear bond strength values were measured using Zwick test machine. Cavities on sixty healthy premolar teeth were filled with the fissure sealants containing 0-5 wt.% of nano b-TCP. The samples were assessed for remineralization under scanning electron microscopy (SEM) and EDAX. Kolmogorov-Smirnov test, One-way ANOVA and Tukey's Post Hoc analysis/HSD were used to analyze the data.Results: There was no significant difference between the flexural strengths/elastic modulus of the 0-5 wt.% nano b-TCP groups (p>0.05). The average flexural strength/elastic modulus of the prepared fissure sealant group (0%) was significantly higher than the commercial fissure sealant group (Clinpro) (p<0.05). There was no significant difference between micro-shear bond strengths of the experimental groups (1-5 wt.%), and between the commercial and the prepared (0%) fissure sealant groups (p>0.05). Examining the samples under SEM showed a significant increase in thickness of the intermediate layer with increasing concentrations of b-TCP NANOPARTICLES (p<0.05).Conclusion: Addition of 1-5 wt.% b-TCP NANOPARTICLES to the fissure sealants significantly increased the remineralization potential without affecting the mechanical properties.

Introduction: Achievement of new drugs with minimal side effects is an important goal in the cancer treatment due to irreversible side effects of conventional drugs. TRICALCIUM PHOSPHATEs as natural bone components have unique characteristics including excellent biocompatibility, high biosorption and superior bioactivity. This research aimed at investigating the inhibitory effect of TRICALCIUM PHOSPHATE (TCP) sintered at different temperatures.Methods: TCP NANOPARTICLES (nTCP) were sintered at three temperatures of 700oC, 900oC and 1000oC, and their structural characterization was examined. Heat treatment of TCP at 900oC was found optimal due to its morphological properties, such as particle size and its crystallinity. The inhibitory effect of optimized nTCP sintered at 900oC was surveyed through in vitro tests.Results: Cell culture assay studies exhibited that such effect depended on the concentration of nTCP. Moreover, the results depicted that the effect was 80%, which could be attributed to the 50 mg.L-1 dose of nTCP.Conclusions: In lower concentrations, higher inhibitory effect of nTCP was observed. In comparison with hydroxyapatite, at low concentrations, anti-cancer properties of TCP were far greater than other calcium PHOSPHATEs.

Introduction: This study focused on preparing a multiscale three-dimensional (3D) scaffold using TRICALCIUM PHOSPHATE NANOPARTICLES (triCaPNPs) in a substrate of poly(acrylic acid) (PAA) polymer for controlled release of exosomes in bone tissue engineering. Methods: A scaffold was fabricated with a material mixture containing acrylic acid (AA) monomer, N, N’,-methylenebisacrylamide (MBAA), ammonium persulfate (APS), sodium bicarbonate (SBC), and triCaPNPs called composite scaffold (PAA/triCaPNPs) via cross-linking and freezedrying methods. The synthesis process was easy and without complex multi-steps. Through mimicking the hybrid (organic-inorganic) structure of the bone matrix, we here chose triCaPNPs for incorporation into the PAA polymer. After assessing the physicochemical properties of the scaffold, the interaction of the scaffold with human umbilical cord mesenchymal stem cells (UCMSCs) such as attachment, proliferation, and differentiation to osteoblast cells was evaluated. In addition, we used DiI-labeled exosomes to verify the exosome entrapment and release from the scaffold. Results: The polymerization reaction of 3D scaffold was successful. Based on results of physicochemical properties, the presence of NANOPARTICLES in the composite scaffold enhanced the mechanical stiffness, boosted the porosity with a larger pore size range, and offered better hydrophilicity, all of which would contribute to greater cell penetration, proliferation, and then better bone differentiation. In addition, our results indicated that our scaffold could take up and release exosomes, where the exosomes released from it could significantly enhance the osteogenic commitment of UC-MSCs. Conclusion: The current research is the first study fabricating a multiscale scaffold using triCaPNPs in the substrate of PPA polymer using a cross-linker and freeze-drying process. This scaffold could mimic the nanoscale structure and chemical combination of native bone minerals. In addition, our results suggest that the PAA/triCaPNPs scaffold could be beneficial to achieve controlled exosome release for exosome-based therapy in bone tissue engineering.

Statement of the Problem: It is important to use orthodontic composites with favorable properties, which are easily removed after the end of the treatment but not easily debonded during treatment. NANOPARTICLES have drawn attention for their antibacterial properties when added to composite resins. However, the effect of addition of nanoparticle on shear bond strength is not broadly discussed.Purpose: The present study was designed to compare the shear bond strength of orthodontic brackets bonded by orthodontic composite containing silver NANOPARTICLES with orthodontic composite containing amorphous TRICALCIUM PHOSPHATE NANOPARTICLES.Materials and Method: In this ex vivo study, 36 sound extracted human premolars were used and randomly divided into three groups. The brackets were bonded in the first group by composite without NANOPARTICLES, in the second group by composite containing 3% amorphous TRICALCIUM PHOSPHATE NANOPARTICLES and in the third group by composite containing 0.3% silver NANOPARTICLES at the buccal surface of the teeth. The shear bond strengths of the samples were measured 24 hours after preparation by a universal testing machine. Data were analyzed using SPSS 21 software through one-way ANOVA and Tamhane's T2 multiple comparison tests. p Values under 0.05 were considered significant.Results: There was no significant difference between the mean shear bond strength of composite containing amorphous TRICALCIUM PHOSPHATE NANOPARTICLES with composite without NANOPARTICLES (p= 0.142). However, the mean shear bond strength in the composite containing silver NANOPARTICLES was significantly lower than the other two groups (p<  0.001).Conclusion: According to the results of this study, the addition of amorphous TRICALCIUM PHOSPHATE NANOPARTICLES to orthodontic composite does not significantly decrease the shear bond strength while silver NANOPARTICLES reduce the shear bond strength of orthodontic composite.

Background: Some types of implants used for orbital implantation have side effects and complications. In this study we have evaluated beta-TRICALCIUM PHOSPHATE (b-TCP: ChronOS) granules as an orbital implant. Methods: Eighteen rabbits randomly allocated to four groups. Right eye enucleation performed in groups I to III followed by filling with autologous bone particles (n=5), a mixture of autologous bone particles and pure b-TCP granules (n=5), a mixture of autologous bone marrow and pure b-TCP granules (n=5). Right eye evisceration was done in group IV (n=3), and then filled with one of the aforementioned materials used in groups I, II and III. After 12 weeks, exenterated contents were compared by determining the volumes of the globes, area densitometry using dual-energy x-ray absorptiometry. Results: There was no significant difference between the volumes of enucleated globes before (groups I: 2.6±0.39, II: 2.6±0.12 and III: 2.5±0.3 (ml) and after surgery; (groups I: 2.5±0.4, II: 2.50±0.2 and III: 2.4±0.3). There was also no significant differences among the densities of exenterated contents of all groups; (I: 175±3, II: 165±1 and III: 174±3 mg/cm2). In all enucleated groups, histopathologic evaluations showed remarkable vascularization and fibrous ingrowth which were remarkable in eviscerated group. No significant complication was observed. Conclusion: b-TCP granules offer good cosmetic results with low risk of infection and extrusion. However, further studies are required before they can be used in human as a new orbital implant.