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Statement of Problem: Blood contamination is a common problem in dentistry that can decrease bond strength dramatically which may be affected by methods of decontamination as well. Purpose: The aim of this study was to evaluate and compare the influence of blood contamination on shear bond strength of composite and compomer to dentin using Prompt L-Pop as an adhesive system. Also, to assess the effectiveness of different surface treatments on the bond strength. Materials and Methods: In this experimental study, 120 molar teeth were sectioned to provide flat occlusal dentinal surfaces. Specimens were embedded in acrylic resin with the flat surface exposed. The dentinal expose surfaces were polished to 600 grit. The teeth were randomly divided into five groups of twelve specimens (F1–F5) for compomer material and five other groups (Z1- Z5) for composite resin. After application of Promt L-Pop to dentinal surfaces of specimens, the surfaces in all groups, except for F1 and Z1, (as controls) were contaminated with human blood and then one of the following surface treatments was applied. Groups F2 and Z2 without any treatment, groups F3 and Z3 rinsing with water, groups F4 and Z4 rinsing with water and reapplication of adhesive, groups F5 and Z5 rinsing with NaOCl and using Prompt L-Pop again. Restorative materials were applied to treated surfaces using plastic molds. After thermocycling, shear bond strengths, mode of failures and morphology of dentin-material interfaces were evaluated. The data were statistically analyzed using Factorial analysis of Variance, One-Way ANOVA, Duncan, T-student and Chi-Square tests with P

Nowadays, application of implants as a new method for replacing extracted teeth have been improved. So, many researches have been performed for improving the characteristics of implants. The aim of this study was to design and produce a desired coating in order to obtaining two goals including; improvement of the corrosion behavior of metallic endodontic implant and the bone osseointegration simultaneously. Stainless steel 316L (SS), cobalt-chromium alloy (Vit) and commercial pure titanium (cpTi) were chosen as metallic substrates and hydroxyapatite coating (HAC) were performed by plasma-spraying (PS) process on three different substrates. A novel double layer Hydroxyapatite/Titanium (HA/Ti) composite coating composed of a HA top layer and a Ti under layer was prepared using PS and physical vapor deposition (PVD) process respectively on SS. Structural characterization techniques including XRD, SEM and EDX were utilized to investigate the microstructure, morpholgy and crystallinity of the coatings. Electrochemical potentiodynamic tests were performed in physiological solutions in order to determine and compare the corrosion behavior of the coated and uncoated specimens behavior as an indication of biocmpatibility. Results indicated that the cpTi possesses the highest and SS the lowest corrosion resistance (highest corrosion current density) between uncoated substrates. This trend was independent to the type of physiological environment. The HA coating decreased the corrosion current density of HA coated metallic implants but did not change that trend. HAC acted as a mechanical barrier on the metallic substrate but could not prevent the interaction between metallic substrate and environment completely. The HA/Ti composite coating improved the corrosion behavior of SS. The corrosion current density of HA/Ti coated SS decreased and was exactly similar to single HA coated cpTi in physiological solutions. The results indicated that HA/Ti composite coated SS could be used as an endodontic implant and two goals including improvement of corrosion resistance (biocompatibiiity) and bone osseointegration could be obtained simultaneously.

Bone osseointegration around dental implant can cause earlier stabilization and fixation of implant and reduce healing time. Hydroxyapatite coating can affect bone osseointegration and enhance its rates. The aim of this study was comparison of osseointegration between plasma sprayed hydroxyapatite coated and uncoated dental implants in cats. Four endodontic implants including, vitallium and two stainless steel with and without hydroxyapatite coating were prepared and placed in mandibular canines of 20 cats after completion of root canal treatment and osseous preparation. After a healing period of 4 months, investigation by scanning electron microscopy showed significant difference in ossointegration between coated and uncoated dental implants and average bone osseointegration of coated implants was more than uncoated implants.

Characterization of bioceramics coating and evaluation of the influence of kind of coating on"nthe implantation has been developed in recent years."nDifferent bioceramics coating like calcium phosphate, hydroxyapatite, fluorapatite and bioglass were"ncoated on dental and orthopedic implants. In-vitro and in-vivo experiments were done for evolution of"nimplant success and reliability and study of factors, which may influence the results."nResearches indicate that different bioceramic coating may affect the bone bonding mechanism."nBiodegredable calcium phosphate coating can be resorbed and be replaced with bone tissues."nHydroxyapatite cause earlier stabilization of dental implant in surrounding bone (biological fixation) and"nreduce healing time. Bioglass can protect substrate and provide interfacial attachment to bone.

Wear characteristics of dental amalgams were investigated by in vivo and in vitro tests. Wear"nof dental amalgam was studied and evaluated using a three - body abrasion test and Pin-On-Disk"nmethod. Porcelain was used for preparing disk and materials such as toothpaste, artificial saliva and"nnaturally saliva were used as the third material that was contributed in tribologic system"nThe results showed that effects of various toothpastes on the wear of dental amalgam are considerably"ndifferent and size, shape and chemical composition of amalgam are important too.

Statement of Problem: Cobalt-base alloys are widely used for fabrication of dental structures and dental and orthopedic surgical implants due to their biocompatibility. Application of coatings on the implants with bioactive materials improves their fixations in human body. Performing the operation during the casting process is very interesting due to the economical benefits and higher quality. Purpose: The aim of this study was surface bioactivation of the dental Co-Cr-Mo alloy via performing the bioactive coating on the surface of the alloy during the investment casting process and evaluating the properties of the coating. Methods and Material: In the present experimental research, the Co-Cr-Mo alloy (ASTM F-75) specimens were poured into the molds prepared via investment mold technique. The internal surface of the molds was previously coated with hydroxyapatite powder via painting coating method. The obtained specimens were analyzed by x-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy and optical microscopy. The prepared specimens were immersed in simulated body fluid (SBF) at 37 °C for 4 weeks in order to evaluate the bioactivity of the surface of the specimens. Results: A desired coating enriched with phosphor and calcium with a thickness of 100-160 micrometer was formed on the surface of Co-Cr-Mo alloy. Formation of bone-like apatite on the surface of coated Co-Cr-Mo alloy specimen, after 4 week immersion in SBF, was the indication of surface bioactivity of the obtained specimens. Conclusion: Preparation of hydroxyapatite coating during the investment casting process is an economical method to form a bioactive surface on the metallic cast implants. The surface bioactivity of the dental and orthopeadic implants can promote the osteointegration and better biological fixation. [ABSTRACT FROM AUTHOR]

Background: Metal screws are commonly used for fracture fixations. However, the high modulus of elasticity relative to bones and releasing metallic ions by the metal screw needed a second surgery to remove the implant after the healing period. Furthermore, the removal of metal screws following the healing of the bone is a serious problem that can lead to refracture due to the presence of holes in the screw. Bioresorbable screws can overcome most of the problems associated with metallic screws which motivated research on manufacturing nonmetallic screws., Methods: In this study, three-layer poly L-lactic acid/bioactive glass composite screws were manufactured according to functionally graded material theory, by the forging process. All of the physical and chemical parameters in the manufacturing stages from making composite layers to the forging process were optimized to obtain suitable mechanical properties and durability off the screw in load-bearing positions., Results: The tri-layer composite screw with unidirectional, ±20° angled, and random fibers orientation from core to shell shows a flexural load of 661.5 ± 20.3 (N) with a decrease about 31% after 4-week degradation. Furthermore, its pull-out force was 1.8 ± 0.1 (N) which is considerably more than the degradable polymeric screws. Moreover, the integrity of the composite screws was maintained during the degradation process., Conclusions: By optimizing the manufacturing process and composition of the composite and crystallinity, mechanical properties (flexural, torsion, and pull-out) were improved and making it a perfect candidate for load-bearing applications in orthopedic implants. Improving the fiber/matrix interface through the use of a coupling agent was also considered to preserve the initial mechanical properties. The manufactured screw is sufficiently robust enough to replace metals for orthopedic load-bearing applications., Competing Interests: There are no conflicts of interest., (Copyright: © 2023 Journal of Medical Signals & Sensors.)

Aim: To investigate whether the estimation of cerebrospinal fluid (CSF) and brain YKL-40 levels may be used as an efficient biomarker for Parkinson's disease (PD). Methods: Lipopolysaccharides (LPS) was injected into the right substantia nigra pars compacta (SNpc). Rats were divided into: control group, early LPS-induced PD group (14 days), and advanced LPS-induced PD group (28 days). YKL-40 and other related factors were detected in CSF and brain tissue. Results: Increased expression of YKL-40 was observed in brain tissue and CSF of PD-induced rats associated with triggered inflammatory cytokine release. Conclusion: The current study was limited to detecting YKL-40 and other inflammatory factors in brain and CSF. YKL-40 may be considered as an early biomarker and therapeutic target for PD.

Our previous studies have been focused on the design, optimization and manufacture of a partially resorbable composite bone plate consisting of a poly l-lactic acid matrix reinforced with braided fabrics bioactive glass fibers (PLLA/BG). In the present study, the response of the composite samples, the degradation rate, the inflammatory response, fibrous capsule formation and tissue-implant bonding to the in-vivo environment were assessed via implantation in the rabbit subcutaneous tissue. Despite the presence of both enzymatic degradation and hydrolysis processes within the body, the rate of the molecular weight loss as an indicator of degradation did not show a significant difference with the in-vitro conditions. It was predicted that strength loss would show the same trend since it was a consequence of molecular chain disruption and the loss of molecular weight. Inexistence of chronic inflammation, as confirmed by our previous results on the controlled degradation rate, also showed the maintenance of the physiological pH in the peripheral environment of the implant. Moreover, lack of the fibrous capsule tissue around the implant indicated that the implant was bioactive. In addition, given the composition of the bioactive glass fibers, that could be bonded to soft and hard tissues, tissue bonding with the PLLA/BG composite samples was also observed, thereby confirming the bioactivity and biocompatibility of the proposed bone plate.

The aim of this study was to fabricate and characterize biodegradable polycaprolactone fumarate(PCLF)/gelatin-based nanocomposite incorporated with the 0, 5 and 10 wt% silicon and magnesium co-doped fluorapatite nanoparticles (Si-Mg-FA) membranes using electrospinning process for guided bone regeneration (GBR) and guided tissue regeneration (GTR) applications. Results demonstrated the formation of randomly-oriented and defect-free fibers with various fiber sizes depending on the Si-Mg-FA content. Moreover, incorporation of 5 wt% Si-Mg-FA significantly improved the mechanical strength (1.5times) compared to the mechanical strength of PCLF/gelatin membrane and nanocomposite with 10 wt% nanoparticles. There was no clear difference between degradation rate of PCLF/gelatin and PCLF/gelatin with 5 wt% nanoparticles at 7, 14 and 28 days of immersion in phosphate buffer saline while 10 wt% nanoparticles significantly increased biodegradation of PCLF/gelatin, and no cytotoxic effect of membranes was seen. Finally, scanning electron microscopy (SEM) micrographs of fibroblast cells cultured on the samples demonstrated that the cells were completely attached and spread on the surface of nanocomposites. In summary, PCLF/gelatin membranes consisting of 5 wt% Si-Mg-FA nanoparticles could provide appropriate mechanical and biological properties and fairly good degradation rate, making it appropriate for GTR/GBR applications., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Bioactive glasses (BG) is one of the well-known materials that used as dental and bone implants, for this reason it is always interesting for researchers has been to increase BG efficiency in the bone tissue engineering. The aim of this study was to evaluate the osteoinductivity of BG different composition nanoparticles with SiO2-CaO-P2O5. The 45S, 58S, and 63S compositions were prepared via the sol-gel technique. Characterization techniques such as x-ray diffraction, field emission scanning electron microscopy (FE-SEM), and laser Doppler electrophoresis (LDE) were used. The osteoinductive capacity of prepared nanoparticles was investigated using unrestricted somatic stem cells (USSC). The particle size of the samples with an amorphous structure mainly ranged less than 40 nm. The zeta potential was negative for all compositions in distilled water at pH 7.4. Bioactive glass nanoparticles were shown to support proliferation of USSC, as shown by microculture tetrazolium (MTT) assay. During osteogenic differentiation, significantly highest values of alkaline phosphatase (ALP) activity and biomineralization were observed on 45S BG. Subsequently, these markers were measured in higher amounts in USSC on 58S and 63S BG compared with tissue culture polystyrene. The nanometric particle size, osteoinductivity, and negative zeta potential make this material a possible candidate for bone tissue engineering applications.

The purpose of the study reported in this Research Communication was to evaluate alterations in concentration of total antioxidant capacity (TAC) of plasma, plasma total thiols as markers of oxidative protein damage and malondialdehyde (as a final product of lipid peroxidation) in samples obtained at different stages of the lactation cycle and dry period of dairy cows. We found that TAC was significantly lower in the primiparous cows compared to multiparous cows. This study clearly demonstrates a need for monitoring primiparous cows during the production cycle, especially when they are faced with severe metabolic conditions. Furthermore, TAC may be a sensitive, reliable and useful indicator for measurement of cumulative effects of antioxidants as an addition to metabolic profile tests, which are currently used to analyse dairy cattle health.

In this work, cobalt-based alloy/nano bioactive glass (NBG) composites with 10, 15 and 20wt% NBG were prepared and their bioactivity after immersion in simulated body fluid (SBF) for 1 to 4weeks was studied. Scanning electron microscopy images of two- step sintered composites revealed relatively dense microstructure. The results showed that density of composite samples decreased with increase in NBG amount. The microstructure analysis as well as energy dispersive X-ray analysis (EDX) revealed that small amount of calcium phosphate phases precipitates on the surface of composite samples after 1week immersion in SBF. After 2weeks immersion, considerable amounts of cauliflower-like shaped precipitations were seen on the surface of the composites. Based on EDX analysis, these precipitations were composed mainly from Ca, P and Si. The observed bands in the Fourier transform infrared spectroscopy of immersed composites samples for 4weeks in SBF, were characteristic bands of hydroxyapatite. Therefore it is possible to form hydroxyapatite layer on the surface of composite samples during immersion in SBF. The results indicated that prepared composites unlike cobalt-based alloy are bioactive, promising their possibility for implant applications., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The aim of this work was preparation, characterization, bioactivity and biocompatibility evaluation of Mg-substituted fluorapatite (Mg-FA) nanopowders. Mg-FA nanopowders with a chemical composition of Ca10-xMgx(PO4)6F2, with x=0, 0.5, 1, and 2 were prepared by mechanically activated method. The in vitro bioactivity was investigated by soaking the powders in simulated body fluid (SBF) for various time periods to analyze the nucleation and growth of bone-like apatite on the surface of the samples. Cell viability and cell attachment were studied by MTT assay. Results indicated that the bioactivity of all of samples with different Mg content was improved compared with the pure FA. However, the mechanism of bioactivity is different and depends on the amount of Mg substitution. Finally, cell culture suggested that the addition of Mg(2+) has no adverse effect and Mg-FA samples have good biocompatibility. The Mg-FA material shows potential in satisfying the requirements of biomedical applications., (Copyright © 2016 Elsevier B.V. All rights reserved.)

This study was conducted to evaluate the effects of dietary pomegranate seed pulp (PSP) on meat color and lipid stability of kids. Thirty-two Mahabadi male kids were randomly assigned to one of four diets with different levels of PSP: 1 - diet without PSP (Control), 2 - diet containing 5% PSP (PSP5), 3 - diet containing 10% PSP (PSP10), and 4 - diet containing 15% PSP (PSP15). The kids were slaughtered at the end of the study and m. longissimus lumborum (LL) was sampled. The TBARS values of both raw and cooked meat were decreased (P<0.0001) by increasing levels of PSP in the diet. The meat of kids fed PSP15 showed higher a* and C* values (P<0.01) and lower H* and b* values (P<0.001), than kids fed with Control diet. The results of this experiment indicated that replacing barley and corn grains with PSP in the diet may improve the color and lipid stability of kid meat., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

The goal of the present research was to fabricate, characterize, and evaluate mechanical and biological properties of Co-base alloy composites with different amounts of hydroxyapatite (HA) nanopowder reinforcement. The powder of Co-Cr-Mo alloy was mixed with different amounts of HA by ball milling and it was then cold pressed and sintered. X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were used. Microhardness measurement and compressive tests were also carried out. Bioactivity behavior was evaluated in simulated body fluid (SBF). A significant decrease in modulus elasticity and an increase in microhardness of the sintered composites were observed. Apatite formation on the surface of the composites showed that it could successfully convert bioinert Co-Cr-Mo alloy to bioactive type by adding 10, 15, and 20wt.% HA which have lower modulus elasticity and higher microhardness., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Background: The aim of this study was to evaluate the interaction of bioactive and biodegradable poly (lactide-co-glycolide)/bioactive glass/hydroxyapatite (PBGHA) and poly (lactide-co-glycolide)/bioactive glass (PBG) nanocomposite coatings with bone., Materials and Methods: Sol-gel derived 58S bioactive glass nanoparticles, 50/50 wt% poly (lactic acid)/poly (glycolic acid) and hydroxyapatite nanoparticles were used to prepare the coatings. The nanocomposite coatings were characterized by scanning electron microscopy, X-ray diffraction and atomic force microscopy. Mechanical stability of the prepared nanocomposite coatings was studied during intramedullary implantation of coated Kirschner wires (K-wires) into rabbit tibia. Titanium mini-screws coated with nanocomposite coatings and without coating were implanted intramedullary in rabbit tibia. Bone tissue interaction with the prepared nanocomposite coatings was evaluated 30 and 60 days after surgery. The non-parametric paired Friedman and Kruskal-Wallis tests were used to compare the samples. For all tests, the level of significance was P < 0.05., Results: The results showed that nanocomposite coatings remained stable on the K-wires with a minimum of 96% of the original coating mass. Tissue around the coated implants showed no adverse reactions to the coatings. Woven and trabecular bone formation were observed around the coated samples with a minimum inflammatory reaction. PBG nanocomposite coating induced more rapid bone healing than PBGHA nanocomposite coating and titanium without coating (P < 0.05)., Conclusion: It was concluded that PBG nanocomposite coating provides an ideal surface for bone formation and it could be used as a candidate for coating dental and orthopedic implants.

The well-known treatment of the alveolar bone defects is guided tissue regeneration (GTR). Engineered membranes combined with osteo-differentiation factors have been offered a promising strategy for GTR application. Recently, poly(ε-caprolactone) (PCL)-forsterite (PCL-F) nanocomposite fibrous membranes have been developed. However, PCL-F membranes could not promote bone tissue regeneration. The aim of this research is to encapsulate an osteogenic factor [dexamethasone (DEX)] in PCL-F membranes and evaluate the effects of forsterite nanopowder (particle size = 25-45 nm) and fiber organization on DEX delivery for GTR application. The hypothesis is that the release kinetic and profile of DEX could be controlled through variation of forsterite content (0, 5 and 10 wt%) and fiber arrangement (aligned and random). Results demonstrated while DEX release was sustained over a period of 4 weeks, its kinetic was governed by the membrane architecture and composition. For example, aligned PCL-F nanocomposite fibrous membrane consisting of 10 %(w/v) forsterite nanopowder exhibited the least initial burst release (13 % release in the first 12 h) and allowed sustained release of DEX. Additionally, forsterite nanopowder inclusion changed the kinetic of DEX release from Fickian diffusion to an anomalous transport. The bioactivity of released DEX was estimated using culturing the stem cells from human exfoliated deciduous teeth (SHED) on the membranes. Results demonstrated that proliferation and osteogenic differentiation of SHED could be governed by DEX release process. While DEX release from the membranes decreased SHED proliferation, stimulated the matrix mineralization. Our finding indicated that aligned PCL-F/DEX membrane could be used as a carrier for the sustained release of drugs relevant for GTR trophy.

The aim of the present work was twofold: to prepare biphasic magnesium fluorapatite (MFA) composites with different amounts of alumina using a two-step sintering process, and to evaluate the effects of various amounts of alumina on the mechanical properties, phase stability, and densification of the composite samples. Initially, MFA powders were prepared with different amounts of alumina by mechanical activation and the MFA composite samples were subsequently prepared using the two-step sintering (TSS) method. In order to determine the appropriate temperature of the first step sintering, conventional sintering of MFA/50% alumina was carried out at temperatures in the range of 1000-1300°C. X-ray diffraction and scanning electron microscopy (SEM) techniques were used to characterize the prepared MFA/alumina composites. The results showed fracture toughness and hardness in the MFA/50% alumina composite samples to increase as a result of alumina addition to their maximum values of 5.82±1.05MPam(1/2) and 22.09±3.5GPa, respectively., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Acceleration of bone healing has always been a major challenge in orthopedic surgery, the aim of this study was an evaluation of the biological effects of zirconia-stabilized yttria on bone healing, using an in vivo model. Nano-hydroxyapatite powder with zirconia-stabilized yttria were inserted in rabbit tibia and then histologically analyzed and compared with non-treated controls so thirty six. New Zealand white male rabbits randomly divided into two groups of 18 rabbits each. A cortical hole of 4 mm diameter and 8 mm depth in each tibia was drilled. In group I, the defect was left empty, whereas in group II, the bone defect was packed with nano-hydroxyapatite/5% zirconia stabilized with yttria. Histological evaluations were performed at two, four and six weeks after the implantation. Microscopic changes on two groups along with the time course were scored and statistical analysis showed that the average scores in group II were significantly higher than the other groups (p < 0.05). Histological analysis was shown to be significantly improved by the nano-hydroxyapatite/5% zirconia stabilized with yttria compared with the control group, suggesting that this biomaterial promote the healing of cortical bone, presumably by acting as an osteoconductive.

Composite scaffolds consisting of polymers reinforced with ceramic nanoparticles are widely applied for hard tissue engineering. However, due to the incompatible polarity of ceramic nanoparticles with polymers, they tend to agglomerate in the polymer matrix which results in undesirable effects on the integral properties of composites. In this research, forsterite (Mg2SiO4) nanoparticles was surface esterified by dodecyl alcohol and nanofibrous poly(ε-caprolactone)(PCL)/modified forsterite scaffolds were developed through electrospinning technique. The aim of this research was to investigate the properties of surface modified forsterite nanopowder and PCL/modified forsterite scaffolds, before and after hydrolytic treatment, as well as the cellular attachment and proliferation. Results demonstrated that surface modification of nanoparticles significantly enhanced the tensile strength and toughness of scaffolds upon 1.5- and 4-folds compared to unmodified samples, respectively, due to improved compatibility between matrix and filler. Hydrolytic treatment of scaffolds also modified the bioactivity and cellular attachment and proliferation due to greatly enhanced hydrophilicity of the forsterite nanoparticles after this process compared to surface modified samples. Results suggested that surface modification of forsterite nanopowder and hydrolytic treatment of the developed scaffolds were effective approaches to address the issues in the formation of composite fibers and resulted in development of bioactive composite scaffolds with ideal mechanical and structural properties for bone tissue engineering applications., (© 2013.)

The nanoparticles of oligochitosan-water soluble tragacanth (OCH-WST) as novel gene carriers have been prepared and their transfection efficiency has been investigated on Hela and HepG2 cell lines. Different OCH:WST weight ratios were prepared to obtain particles with low size distribution and high surface charge, and also in range of below 200 nm. Nanoparticles with 132.5 ± 6.77 nm size, polydispersity index 1.92 ± 0.061, surface charge 30.45 ± 1.84 and spherical morphology, have been chosen as gene carrier. Nanoparticle-DNA complexes (nanoplexes) showed better transfection efficiency in both Hela and HepG2 cells than chitosan polyplexes, with 1.26 × 10(6) versus 9.05 × 10(5) and 7.76 × 10(5) versus 2.16 × 10(5), respectively. Higher transfection efficiency of nanoplexes could be attributed to their weaker complexation. Decreasing of transfection in presence of galactose in HepG2 cells, indicated receptor mediated endocytosis of nanoplexes. These properties all together, make OCH-WST nanoparticles as potential gene carrier for active gene delivery into cells containing sugar receptors., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The ability to mimic the structure of the natural extracellular matrix is a successful key for guided bone regeneration (GBR). For the regeneration of highly organized structures such as heart and bone, aligned fibrous membranes could provide anisotropic mechanical and biological properties which are adequate topographic guidance to cells. Here, novel nanofibrous membranes were developed through electrospinning of PCL-forsterite nanopowder. The membranes were characterized with regard to structural and mechanical properties, degradation, bioactivity and cellular interactive responses. Results showed that optimized nanofibrous composite membrane with significantly improved tensile strength and elastic modules was achieved through addition of 10 wt% forsterite nanopowder into PCL membrane. Addition of forsterite nanopowder decreased the average fiber diameters from 872±361 nm (pure PCL membrane) to 258±159 nm (PCL-10 wt% forsterite membrane). At higher forsterite contents (>10 wt%), the agglomeration of nanoparticles was observed which resulted in reduced mechanical properties. Aligned fibrous membranes revealed smaller fiber sizes and significantly enhanced and anisotropic mechanical properties compared to random ones suggesting that fiber alignment has a profound effect on the structural properties of membranes. Forsterite nanopowder increased the degradation rate showing enhanced hydrophilicity and induced apatite formation in simulated body fluid. Furthermore, composite nanofibrous membranes possessed significantly improved cellular responses in terms of attachment, proliferation and mineralization of pre-osteoblasts compared to PCL membrane. Thus, the currently developed nanofibrous composite membranes embedded in forsterite nanopowder expected to be attractive in GBR membrane applications., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

This work deals with the biocompatibility of dense nano- and micro-structured Hydroxyapatite/Titania composites prepared by two step and conventional sintering, respectively. By application of two step sintering, it was shown that the final grain size of HA-15 wt.% TiO2 is maintained lower than 100 nm while by the application of conventional sintering it reaches higher than 100 nm. Biocompatibility of the dense bulks was evaluated by cell attachment and proliferation experiments. Cell morphology, and viability on each nano- and micro-structured Hydroxyapatite/Titania composites were examined at different time points. The nanostructured HA/Titania dense bulk exhibited higher cell viability than a microstructured one. In addition, the effects of ionic products from nano- and micro-structured bulk dissolution on osteoblasts were studied. The MTT test confirmed that the products from nanostructured HA/Titania dense bulk significantly promoted osteoblast proliferation within a certain concentration range., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Background: The interim restorative materials should have certain mechanical properties to withstand in oral cavity. The aim of this study was to evaluate the hardness and wear resistance of interim restorative materials., Materials and Methods: Fifteen identical rectangular shape specimens with dimensions of 2 mm × 10 mm × 30 mm were made from 7 interim materials (TempSpan, Protemp 3 Garant, Revotek, Unifast LC, Tempron, Duralay, and Acropars). The Vickers hardness and abrasive wear of specimens were tested in dry conditions and after 1 week storage in artificial saliva. The depth of wear was measured using surface roughness inspection device. Data were subjected to Kruskal-Wallis and Mann-Whitney tests. The Pearson correlation coefficient was used to determine the relationship between hardness and wear (α =0.05)., Results: TempSpan had the highest hardness. The wear resistance of TempSpan (in dry condition) and Revotek (after conditioning in artificial saliva) was significantly higher (P < 0.05). There was no statistically significant correlation between degree of wear and hardness of the materials (P = 0.281, r = -0.31)., Conclusion: Hardness and wear resistance of interim resins are material related rather than category specified.

In this study, biodegradation and biocompatibility of novel poly(ε-caparolactone)/nano fluoridated hydroxyapatite (PCL-FHA) scaffolds were investigated. The FHA nanopowders were prepared via mechanical alloying method and had a chemical composition of Ca(10)(PO(4))(6)OH(2-x )F(x) (where x values were selected equal to 0.5 and 2.0). In order to fabricate PCL-FHA scaffolds, 10, 20, 30 and 40 wt% of the FHA were added to the PCL. The PCL-FHA scaffolds were produced by the solvent casting/particulate leaching using sodium chloride particles (with diameters of 300-500 μm) as the porogen. The phase structure, microstructure and morphology of the scaffolds were evaluated using X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy techniques. Porosity of the scaffolds was measured using the Archimedes' Principle. In vitro degradation of PCL-FHA scaffolds was studied by incubating the samples in phosphate buffered saline at 37°C and pH 7.4 for 30 days. Moreover, biocompatibility was evaluated by MTT assay after seeding and culture of osteoblast-like cells on the scaffolds. Results showed that the osteoblast-like cells attached to and proliferated on PCL-FHA and increasing the porosity of the scaffolds increased the cell viability. Also, degradation rate of scaffolds were increased with increasing the fluorine content in scaffolds composition.

This study aimed at preparation and in vitro and in vivo evaluation of novel bioactive, biodegradable, and antibacterial nanocomposite coating for the improvement of stem cells attachment and antibacterial activity as a candidate for dental implant applications. Poly (lactide-co-glycolide)/bioactive glass/hydroxyapatite (PBGHA) nanocomposite coating was prepared via solvent casting process. The nanoparticle amounts of 10, 15, and 20 weight percent (wt%) were chosen in order to determine the optimum amount of nanoparticles suitable for preparing an uniform coating. Bioactivity and degradation of the coating with an optimum amount of nanoparticles were evaluated by immersing the prepared samples in simulated body fluid and phosphate buffer saline (PBS), respectively. The effect of nanocomposite coating on the attachment and viability of human adipose-derived stem cells (hASCs) was investigated. Kirschner wires (K-wires) of stainless steel were coated with the PBGHA nanocomposite coating, and mechanical stability of the coating was studied during intramedullary implantation into rabbit tibiae. The results showed that using 10 wt% nanoparticles (5 wt% HA and 5 wt% BG) in the nanocomposite could provide the desired uniform coating. The study of in vitro bioactivity showed rapid formation of bone-like apatite on the PBGHA coating. It was degraded considerably after about 60 days of immersion in PBS. The hASCs showed excellent attachment and viability on the coating. PBGHA coating remained stable on the K-wires with a minimum of 96% of the original coating mass. It was concluded that PBGHA nanocomposite coating provides an ideal surface for the stem cells attachment and viability. In addition, it could induce antibacterial activity, simultaneously.

Background: In recent years, bioceramics have been favored by biomaterials scientists and researchers. Due to their special and distinctive features, bioactive glass and hydroxyapatite possess a higher place among different types of bioceramics., Method: In this study, the effect of 63S bioactive glass and bone-derived hydroxyapatite particles on the proliferation of human bone-marrow stem cells (hMSCs) was investigated. Bioactive glass particles were made via sol-gel method and hydroxyapatite was obtained from bovine bone. The particle size and morphology were investigated by scanning electron microscope (SEM). Then the in vitro cytotoxicity of particles was evaluated using MTT assay. SEM showed that bioactive glass particles were in the nanoscale range and had tendency towards agglomeration. It was also confirmed that the hydroxyapatite particles were agglomerations of crystals cca 50-500 nm across., Results: The results of MTT assay confirmed the viability and proliferation of hMSCs in contact with bioactive glass and bone-derived HA particles. The fabricated particles in combination with stem cells were shown to hold promising potential for further applications in tissue engineering and regenerative medicine.

The biphasic calcium phosphate (BCP) yields higher bioactivity and efficiency than the Hydroxyapatite (HA) alone. The HA/β-TCP ratio significantly affects BCP bioactivity as well as the extent of BCP resorption. In this study, the BCP coating on ASTM F-75 cobalt base alloy during the investment casting process was investigated. For this purpose, molten metal was poured at 1,470°C into previously coated investment molds preheated to 750, 850, 950, 1,050°C in order to investigate the effect of mold preheating temperatures on coating phase transformations. For in vitro evaluation, samples were immersed in the simulated body fluid (SBF) at 37°C for 4 weeks and characterized by XRD, SEM, EDS, and optical microscopy. The weight percentages of HA and β-TCP of the specimens were calculated to find that the HA/β-TCP ratio significantly depended on the mold preheating temperature as it caused changes in the dissolution behavior of BCP coating and the bone-like apatite precipitation on coating during in vitro evaluation.

A combination of bioceramics and polymeric nanofibers holds promising potential for bone tissue engineering applications. In the present study, hydroxyapatite (HA), bioactive glass (BG), and tricalcium phosphate (TCP) particles were coated on the surface of electrospun poly(L-lactic acid) (PLLA) nanofibers, and the capacity of the PLLA, BG-PLLA, HA-PLLA, HA-BG-PLLA, and TCP-PLLA scaffolds for bone regeneration was investigated in rat critical-size defects using digital mammography, multislice spiral-computed tomography (MSCT) imaging, and histological analysis. Electrospun scaffolds exhibited a nanofibrous structure with a homogeneous distribution of bioceramics along the surface of PLLA nanofibers. A total of 8 weeks after implantation, no sign of complication or inflammation was observed at the site of the calvarial bone defect. On the basis of imaging analysis, a higher level of bone reconstruction was observed in the animals receiving HA-, BG-, and TCP-coated scaffolds compared to an untreated control group. In addition, simultaneous coating of HA and BG induced the highest regeneration among all groups. Histological staining confirmed these findings and also showed an efficient osseointegration in HA-BG-coated nanofibers. On the whole, it was demonstrated that nanofibrous structures could serve as an appropriate support to guide the healing process, and coating their surface with bioceramics enhanced bone reconstruction. These bioceramic-coated scaffolds can be used as new bone-graft substitutes capable of efficiently inducing osteoconduction and osseointegration in orthopedic fractures and defects.

In this study, the cytotoxicity evaluation of prepared 63S bioactive glass and bone-derived hydroxyapatite particles with yeast and human chondrocyte cells was carried out using isothermal micro-nano calorimetry (IMNC), which is a new method for studying cell/biomaterial interactions. Bioactive glass particles were made via sol-gel method and hydroxyapatite was obtained from bovine bone. Elemental analysis was carried out by XRF and EDXRF. Amorphous structure of the glass and completely crystalline structure of HA were detected by XRD analysis. Finally, the cytotoxicity of bioactive glass and bone-derived HA particles with yeast and cultured human chondrocyte cells was evaluated using IMNC. The results confirmed the viability, growth and proliferation of human chondrocyte cells in contact with 63S bioactive glass, and bone-derived HA particles. Also the results indicated that yeast model which is much easier to handle, can be considered as a good proxy and can provide a rapid primary estimate of the ranges to be used in assays involving human cells. All of these results confirmed that IMNC is a convenient method which caters to measuring the cell-biomaterial interactions alongside the current methods.

Silica-based bioactive glasses are considered promising bone substitutes and tissue regeneration matrices, because of their bioactivity, biocompatibility, osteoconductivity, and possibly even osteoinductivity. The aim of this work was to evaluate the subcutaneous connective tissue reactions to 58S, 63S, and 72S bioactive glass nanopowders. Our previous study showed the antibacterial activities of 58S and 63S bioactive glass nanopowders on aerobic bacteria, while 72S showed no antibacterial effects at all. Bioactive glass nanopowders were prepared via the sol-gel technique. Characterization techniques such as X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and X-ray fluorescent (XRF) were utilized to carry out the phase analysis, study of the structure, particle size and the composition of the synthesized bioactive glasses. To evaluate the subcutaneous connective tissue reactions, the specimens were placed in polyethylene tubes and implanted into the dorsal connective tissue of rats. Empty polyethylene tubes were used as the control and bioactive glass micropowders (NovaBone) was used as a FDA approved bone graft. The evaluation of inflammatory reactions was performed 3, 7, 15, and 28 days after implantation. Results showed a particle size of below 100 nm for samples with amorphous structure. The samples were well tolerated by the tissues over a 28-day evaluation period. The extra tissue reactions of the 72S specimen in comparison with 58S and 63S specimens could be attributed to its higher silica content. It may be concluded that biocompatible 58S and 63S bioactive glass nanopowders with antibacterial activities can be synthesized for the treatment of osseous defects.

Designing and preparation of magnesium alloys with adjustable biocorrosion rates in the human body and precipitation ability of bone-like apatite layer have been of interest recently. Application of metal matrix composites (MMC) based on magnesium alloys might be an approach to this challenge. The aim of this work was fabrication and evaluation of biocorrosion and bioactivity of a novel MMC made of magnesium alloy AZ91 as matrix and fluorapatite (FA) nano particles as reinforcement. Biodegradable Magnesium-nano fluorapatite metal matrix nanocomposite (AZ91-20FA) was made via a blending-pressing-sintering method. In vitro corrosion tests were performed for evaluation of biocorrosion behavior of produced AZ91-20FA nanocomposite. The results showed that the addition of FA nano particles to magnesium alloy can reduce not only the corrosion rate in a simulated body environment but also accelerate the formation of an apatite layer.

This work deals with the fabrication and characterization of nanostructured forsterite bulk. This material may have better biocompatibility and mechanical properties than coarse grain forsterite for the development of bone tissue engineering materials. Nanostructured forsterite bulks were prepared by two step sintering of sol-gel derived forsterite nanopowder. Their sinterability and mechanical properties were then studied. Biocompatibility of the nanostructured forsterite bulk was also evaluated by cell attachment and proliferation experiments. In addition, the effects of ionic products from forsterite nanopowder dissolution on osteoblasts were studied. Results show that dense nanostructured forsterite bulk was prepared with hardness and fracture toughness of about 1102 Hv and 4.3 MPa m(1/2), respectively. Nanostructured forsterite was biocompatible and the MTT test confirmed that the products from forsterite nanopowder dissolution significantly promoted osteoblast proliferation within a certain concentration range. In addition, cells attached to and spread on the surface of nanostructured forsterite bulks. Mechanical properties of the nanostructured forsterite were much higher than that of hydroxyapatite. It was concluded that nanostructured forsterite is a bioactive ceramic with good biocompatibility that can be used as a bone tissue engineering material., (Copyright (c) 2010 Elsevier Ltd. All rights reserved.)

Gene therapy has been considered a strategy for delivery of therapeutic nucleic acids to a specific site. Calcium phosphates are one gene delivery vector group of interest. However, low transfection efficiency has limited the use of calcium phosphate in gene delivery applications. Present work aims at studying the fabrication of strontium substituted calcium phosphate nanoparticles with improved gene delivery related properties. Strontium substituted calcium phosphate was prepared using a simple sol gel method. X-ray diffraction analysis, Fourier transform infrared spectroscopy, transmission electron microscopy, specific surface area analysis, zeta potential measurement and ion release evaluation were used to characterize the samples. This characterization showed strontium and carbonate co-substituted calcium phosphate which resulted in nano size particles with low crystallinity, high specific surface area, positive surface charge, and a high dissolution rate. These improved properties could increase the DNA concentration on the vector as well as the endosomal escape of the complex that leads to higher transfection efficiency of this novel gene delivery vector.

Gene therapy provides a unique approach to medicine as it can be adapted towards the treatment of both inherited and acquired diseases. Recently, calcium phosphate vectors as a new generation of the non viral gene delivery nano carriers have been studied because of their biocompatibility and DNA condensation and gene transfer ability. Substituting cations, like magnesium, affects physical and chemical properties of calcium phosphate nano particles. In this study, Mg(2+) substituted calcium phosphate nano particles have been prepared using the simple sol gel method. X-ray diffraction analysis, Fourier transform infra red spectroscopy, transmission electron microscopy, specific surface area analysis, zeta potential measurement and ion release evaluation were used for characterization of the samples. It was concluded that presence of Mg ions decrease particle size and crystallinity of the samples and increase positive surface charge as well as beta tricalcium phosphate fraction in chemical composition of calcium phosphate. These properties result in increasing the DNA condensation ability, specific surface area and dissolution rate of the samples which make them suitable particles for gene delivery application.

The aim of this work was to evaluate the antibacterial effect of bioactive glass nanopowders. The 58S, 63S, and 72S compositions were prepared via the sol-gel technique. Characterization techniques such as X-ray diffraction, transmission electron microscopy (TEM), Zetasizer, and X-ray fluorescent were used. The antibacterial activity was studied using Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, and Staphylococcus aureus. Cytotoxicity of the samples was evaluated using mouse fibroblast L929 cell line. The chemical compositions of the prepared samples were as predicted, and the particle size of the samples with an amorphous structure mainly ranged over 20-90 nm. At broth concentrations below 50 mg/mL, they showed no antibacterial activity. The 58S showed the highest antibacterial activity with the minimum bactericidal concentrations of 50 and 100 mg/mL for E. coli plus S. aureus and for P. aeruginosa, respectively. The 63S exhibited bactericidal and bacteriostatic effects on E. coli and S. aureus at concentrations of 100 and 50 mg/mL, respectively, at an minimum bactericidal concentrations of 100 mg/mL. However, 72S bioactive glass nanopowder showed no antibacterial effect. They showed no cytotoxicity. It was concluded that bioactive glass nanopowders could be considered as good candidates for the treatment of oral bone defects and root canal disinfection. (c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010.

Different mathematical models were evaluated as candidates to describe ruminal dry matter (DM) and crude protein (CP) degradation kinetics of raw and roasted whole soybeans from data obtained using the in situ polyester bag technique. Three models were used: segmented with up to 3 straight lines (model I), negative exponential (model II), and rational function or inverse polynomial (linear over linear; model III). A fourth, a generalized sigmoidal model, was also considered but the data did not exhibit sigmoidicity, so it was dropped from the analysis. Lagged and nonlagged versions of each model were fitted to the DM and CP disappearance curves of 6 different feeds (2 cultivars of raw or differently heat-processed whole soybean). The comparison between lagged and nonlagged versions of each model, based on statistical and behavior characteristics, showed for all models that the discrete lag parameter did not significantly improve the fit to ruminal DM and CP disappearance curves. The comparison between models (using nonlagged equations) showed that models I and II gave better goodness-of-fit than model III. Based on biological characteristics, models II and III underestimated the undegradable DM and CP fractions, but there was no significant difference between models for extent of degradation.

Objectives: The most common metals and alloys used in dentistry may be exposed to a process of corrosion in vivo that make them cytotoxic. The biocompatibility of dental alloys is primarily related to their corrosion behavior. The aim of this work was to evaluate the corrosion behavior and thus the biocompatibility of the uncoated and coated stainless steels and compare the effect of type of coatings on corrosion behavior., Methods: Three types of coatings, hydroxyapatite (HA), titanium (Ti), and a double-layer HA/Ti on AISI 316L stainless steel were made. HA coating was produced using plasma-spraying technique and Ti coating was made using physical vapor deposition process. In order to perform a novel double-layer composite coating, a top layer of HA was plasma-sprayed over a physical vapor deposited Ti layer on AISI 316L stainless steel. Structural characterization techniques including XRD, SEM and EDX were used to investigate the microstructure, morphology and crystallinity of the coatings. Electrochemical potentiodynamic tests were performed in physiological solutions in order to determine and compare the corrosion behavior of the coated and uncoated specimens as an indication of biocompatibility., Results: Double-layer HA/Ti coating on AISI 316L SS had a positive effect on improvement of corrosion behavior. The decrease in corrosion current densities was significant for these coated specimens and was much lower than the values obtained for uncoated and single HA coated specimens. Ti coating on AISI 316L SS also has a beneficial effect on corrosion behavior. The results were compared with the results of corrosion behavior of HA coated commercially pure titanium (cpTi) and uncoated cpTi., Significance: These results demonstrated that the double-layer HA/Ti coated 316L SS can be used as an endodontic implant and two goals including improvement of corrosion resistance and bone osteointegration can be obtained simultaneously.