Gene expression, micro-CT and histomorphometrical analysis of sinus floor augmentation with biphasic calcium phosphate and deproteinized bovine bone mineral: A randomized controlled clinical trial.

AIMS: The aim of this randomized controlled clinical trial was to compare the gene expression, micro-CT, histomorphometrical analysis between biphasic calcium phosphate (BCP) of 70/30 ratio and deproteinized bovine bone mineral (DBBM) in sinus augmentation. MATERIALS AND METHODS: Twenty-four patients in need for sinus floor augmentation through lateral approach were randomized into BCP 70/30 ratio or DBBM. After at least 6 months of healing, a total of 24 bone specimens were collected from the entire height of the augmented bone at the area of implant placement and underwent micro-CT, histomorphometric and gene expression analysis. The 12 bone specimens of BCP 70/30 ratio were equally allocated to micro-CT and histologic analysis (test group, n = 6) and gene expression analysis (test group, n = 6). Similarly, the 12 bone specimens of DBBM were also allocated to micro-CT and histologic analysis (control group, n = 6) and gene expression analysis (control group, n = 6). The newly formed bone, remaining graft materials and relative change in gene expression of four target genes were assessed. RESULTS: The micro-CT results showed no statistically significant difference in the ratio of bone volume to total volume (BV/TV ratio) for the two groups (BCP 41.51% vs. DBBM 40.97%) and the same was true for residual graft material to total volume (GV/TV ratio, BCP 9.97% vs. DBBM 14.41%). Similarly, no significant difference was shown in the histological analysis in terms of bone formation, (BCP 31.43% vs. DBBM was 30.09%) and residual graft area (DBBM 40.76% vs. BCP 45.06%). With regards to gene expression, the level of ALP was lower in both groups of bone grafted specimens compared with the native bone. On the contrary, the level of OSX, IL-1B and TRAP was higher in augmented bone of both groups compared with the native bone. However, the relative difference in all gene expressions between BCP and DBBM group was not significant. CONCLUSIONS: The BCP, HA/ß-TCP ratio of 70/30 presented similar histological and micro-CT outcomes in terms of new bone formation and residual graft particles with DBBM. The gene expression analysis revealed different gene expression patterns between augmented and native bone, but showed no significant difference between the two biomaterials.

Calcium phosphate ceramic as a model for enamel substitute material in dental applications.

OBJECTIVE: This study aimed to develop enamel substitute material using a mechanochemical technique. MATERIALS AND METHODS: Hydroxyapatite was synthesized with and without tricalcium phosphate under uniaxial pressing of 10 and 17 MPa (HA10, HA17, BCP10, and BCP17), followed by sintering at 1250 °C for 2 h. Human enamel and dentin blocks were used as control groups. The mechanical properties were determined by compressive strength test and Vickers microhardness. The data were analyzed with one-way ANOVA and LSD post-hoc test (α = 0.05). The phase formation and morphology of the specimens were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). RESULTS: HA17 and HA10 had compressive strength values comparable to enamel and dentin, respectively (p > 0.05). The microhardness of all synthesized groups was significantly higher than that of tooth structures (p < 0.05). From the XRD graphs, only the hydroxyapatite peak was observed in the control and HA groups. SEM images showed homogeneous hydroxyapatite grains in all groups, while the BCP groups contained higher porosities. CONCLUSIONS: Both HA10 and HA17 are suitable for use as the inorganic part of dentin and enamel substitutes.

Stability of guided bone regeneration with two ratios of biphasic calcium phosphate at implant sites in the esthetic zone: A randomized controlled clinical trial.

AIMS: The aim of this randomized, double-blind, clinical trial was to compare the stability of the horizontal dimensions (facial bone thickness) of augmented bone using biphasic calcium phosphate (BCP) with hydroxyapatite/ß-tricalcium phosphate ratio of either 60/40 or 70/30. MATERIALS AND METHODS: Sixty dental implants placed with contour augmentation in the esthetic zone were randomized to 60/40 BCP (n = 30) or 70/30 BCP (n = 30). Cone-beam computed tomographic was used to assess facial bone thickness post-implantation and 6 months later at implant platform and 2, 4, and 6 mm apical to it. RESULTS: The percentage of horizontal dimension reduction was 23.64%, 12.83%, 9.62%, and 8.21% in 70/30 BCP group, while 44.26%, 31.91%, 25.88%, and 21.49% in 60/40 BCP group at the level of the implant platform and 2, 4, and 6 mm apical, respectively. Statistically significant difference was found at 6 months at all levels of measurement (p-value < .05). CONCLUSIONS: BCP bone grafts with HA/ß-TCP ratio of 60/40 and 70/30 showed comparable outcomes for contour augmentation simultaneously with implant placement. Interestingly, the 70/30 ratio was significantly superior in maintaining facial thickness and showed more stable horizontal dimensions of the augmented site.

Assessment of Mechanical/Chemical Properties and Cytotoxicity of Resin-Modified Glass Ionomer Cements Containing Sr/F-Bioactive Glass Nanoparticles and Methacrylate Functionalized Polyacids.

This study prepared low-toxicity, elemental-releasing resin-modified glass ionomer cements (RMGICs). The effect of 2-hydroxyethyl methacrylate (HEMA, 0 or 5 wt%) and Sr/F-bioactive glass nanoparticles (Sr/F-BGNPs, 5 or 10 wt%) on chemical/mechanical properties and cytotoxicity were examined. Commercial RMGIC (Vitrebond, VB) and calcium silicate cement (Theracal LC, TC) were used as comparisons. Adding HEMA and increasing Sr/F-BGNPs concentration decreased monomer conversion and enhanced elemental release but without significant effect on cytotoxicity. Rising Sr/F-BGNPs reduced the strength of the materials. The degree of monomer conversion of VB (96%) was much higher than that of the experimental RMGICs (21-51%) and TC (28%). The highest biaxial flexural strength of experimental materials (31 MPa) was significantly lower than VB (46 MPa) (p < 0.01) but higher than TC (24 MPa). The RMGICs with 5 wt% HEMA showed higher cumulative fluoride release (137 ppm) than VB (88 ppm) (p < 0.01). Unlike VB, all experimental RMGICs showed Ca, P, and Sr release. Cell viability in the presence of extracts from experimental RMGICs (89-98%) and TC (93%) was significantly higher than for VB (4%). Experimental RMGICs showed desirable physical/mechanical properties with lower toxicity than the commercial material.

Influence of Lithium- and Zinc-Containing Bioactive Glasses on Pulpal Regeneration.

OBJECTIVE: To evaluate the potential of modified bioactive glasses containing lithium and zinc as pulp capping materials by investigating the odontogenic differentiation and mineralization response in the tooth culture model. MATERIALS AND METHODS: Lithium- and zinc-containing bioactive glasses (45S5.1Li, 45S5.5Li, 45S5.1Zn, 45S5.5Zn, 45S5.1Zn sol-gel, and 45S5.5Zn sol-gel), fibrinogen-thrombin, and biodentine were prepared to assess Axin2 gene expression at 0, 30 minutes, 1 hour, 12 hours, and 1 day and DSPP gene expression at 0, 3, 7, and 14 days in stem cells from human exfoliated deciduous teeth (SHEDs) using qRT-PCR. The experimental bioactive glasses incorporated with fibrinogen-thrombin and biodentine were placed on the pulpal tissue in the tooth culture model. Histology and immunohistochemistry were analyzed at 2 weeks and 4 weeks. RESULTS: Axin2 gene expression for all experimental groups was significantly higher than the control at 12 hours. The DSPP gene expression for all experimental groups was significantly higher than the control at 14 days. The presence of mineralization foci was significantly higher at 4 weeks for the modified bioactive glasses 45S5.5Zn, 45S5.1Zn sol-gel, and 45S5.5Zn sol-gel as well as Biodentine compared with the fibrinogen-thrombin control. CONCLUSION: Lithium- and zinc-containing bioactive glasses increased Axin2 and DSPP gene expression in SHEDs and can potentially enhance pulp mineralization and regeneration. Zinc-containing bioactive glasses are a promising candidate to be used as pulp capping materials.

Novel Epigenetic Modulation Chitosan-Based Scaffold as a Promising Bone Regenerative Material.

Bone tissue engineering is a complicated field requiring concerted participation of cells, scaffolds, and osteoactive molecules to replace damaged bone. This study synthesized a chitosan-based (CS) scaffold incorporated with trichostatin A (TSA), an epigenetic modifier molecule, to achieve promising bone regeneration potential. The scaffolds with various biphasic calcium phosphate (BCP) proportions: 0%, 10%, 20%, and 40% were fabricated. The addition of BCP improved the scaffolds' mechanical properties and delayed the degradation rate, whereas 20% BCP scaffold matched the appropriate scaffold requirements. The proper concentration of TSA was also validated. Our developed scaffold released TSA and sustained them for up to three days. The scaffold with 800 nM of TSA showed excellent biocompatibility and induced robust osteoblast-related gene expression in the primary human periodontal ligament cells (hPDLCs). To evaluate in vivo bone regeneration potential, the scaffolds were implanted in the mice calvarial defect model. The excellent bone regeneration ability was further demonstrated in the micro-CT and histology sections compared to both negative control and commercial bone graft product. New bone formed in the CS/BCP/TSA group revealed a trabeculae-liked characteristic of the mature bone as early as six weeks. The CS/BCP/TSA scaffold is an up-and-coming candidate for the bone tissue engineering scaffold.

Monomer Conversion, Dimensional Stability, Biaxial Flexural Strength, Ion Release, and Cytotoxicity of Resin-Modified Glass Ionomer Cements Containing Methacrylate-Functionalized Polyacids and Spherical Pre-Reacted Glass Fillers.

The aim of this study was to prepare RMGICs for pulp protection that contain polyacids functionalized with methacrylate groups (CMs) to enable light-activated polymerization without the need for toxic 2-hydroxyethyl methacrylate (HEMA) monomers. The effects of using CM liquids with 0 or 5 wt% HEMA on the physical/mechanical properties and cytotoxicity of the experimental RMGICs were assessed. Spherical pre-reacted glass fillers (SPG) were used as the powder phase. The experimental RMGICs were prepared by mixing SPG with CM liquid (0 wt% HEMA, F1) or CMH liquid (5 wt% HEMA, F2). Commercial materials (Vitrebond, VB; TheraCal LC, TC) were used for the comparisons. The degree of monomer conversion and fluoride release of both F1 and F2 were significantly lower than those of VB. F1 showed comparable biaxial flexural strength with VB but higher strength than TC. The dimensional stability (mass/volume changes) of the experimental materials was comparable with that of the commercial materials. F1 and F2 exhibited higher Sr/Ca ion release and relative cell viability than VB. The use of CMH liquid reduced the strength but enhanced the fluoride release of the experimental RMGICs. In conclusion, the experimental RMGICs showed comparable strength but lower cytotoxicity compared to the commercial RMGICs. These novel materials could be used as alternative materials for pulp protection.

Rheological Properties, Surface Microhardness, and Dentin Shear Bond Strength of Resin-Modified Glass Ionomer Cements Containing Methacrylate-Functionalized Polyacids and Spherical Pre-Reacted Glass Fillers.

The aim of this study was to prepare experimental resin-modified glass ionomer cements (RMGICs) containing low levels of hydroxyethyl methacrylate (HEMA) for pulp protection. Liquid and powder phases of the experimental RMGICs were polyacid functionalized with methacrylate groups and spherical pre-reacted glass fillers (SPG). Two types of liquid phase containing 0 wt. % HEMA (CM liquid) or 5 wt. % HEMA (CMH liquid) were formulated. The experimental RMGICs were prepared by mixing SPG fillers with CM liquid (F1) or CMH liquid (F2). Rheological properties were examined using a strain-controlled rheometer (n = 5). The Vickers microhardness (n = 5) and dentin shear bond strength (SBS) (n = 10) of the materials were tested. Commercial pulp protection materials (Vitrebond and TheraCal LC) were used as comparisons. The viscosity and surface microhardness of F1 (22 m Pa·s, 18 VHN) and F2 (18 m Pa·s, 16 VHN) were significantly higher than those of Vitrebond (6 mPa·s, 6 VHN) and TheraCal (0.1 mPa·s, 7 VHN). The SBS of F1 (10.7 MPa) and F2 (11.9 MPa) was comparable to that of Vitrebond (15.4 MPa) but higher than that of TheraCal LC (5.6 MPa). The addition of 5 wt. % HEMA showed no significant effect on viscosity, surface microhardness, or SBS of the experimental RMGICs. The experimental materials showed higher viscosity and microhardness but similar SBS when compared with the commercial RMGIC.

Buffering capacity and antibacterial properties among bioactive glass-containing orthodontic adhesives.

This study was to evaluate the acid-buffering capacity and antibacterial properties of orthodontic adhesives containing bioactive glasses (BAGs) (45S5, 45S5F, S53P4), Hydroxyapatite, beta-tricalcium phosphate, and Canasite. Fillers comprising 15 wt% bioactive glasses, HAp, ß-TCP, and Canasite incorporated with 55 wt% silanated glass were added to a mixture of UDMA/TEGDMA. Acid-buffering capacity was tested by exposing disc-shaped samples of each adhesive to medium of bacteria-produced acids, and pH changes were recorded at 24 and 48 h. Antibacterial properties were assessed by indirect testing by exposing polymerized adhesive samples to a medium and direct testing by immersing the specimens in solutions containing S. mutans and S. sanguinis. A significant buffering capacity was shown by the 45S5, 45S5F and S53P4 BAG adhesives. The antibacterial properties were not significant in all experimental adhesives. Therefore, the experimental orthodontic adhesives containing BAGs demonstrated a significant buffering capacity but did not show significant antibacterial properties against S. mutans and S. sanguinis.

Bone regeneration of a polymeric sponge technique-Alloplastic bone substitute materials compared with a commercial synthetic bone material (MBCP+TM technology): A histomorphometric study in porcine skull.

BACKGROUND: Polymeric sponge technique is recommended for developing the desired porosity of Biphasic calcium phosphate (BCP) which may favor bone regeneration. PURPOSE: To investigate the healing of BCP with ratio of HA30/ß-TCP70 (HA30) and HA70/ß-TCP30 (HA70) polymeric sponge preparation, compare to commercial BCP (MBCP+TM). MATERIALS AND METHODS: Materials were tested X-ray diffraction (XRD) pattern and scanning electron microscope (SEM) analysis. In eight male pigs, six calvarial defects were created in each subject. The defects were the filled with 1 cc of autogenous bone, MBCP+TM (MBCP), HA30, HA70, and left empty (negative group). The new bone formations, residual material particles and bone-to-graft contacts were analyzed at 4, 8, 12 and 16 weeks. RESULTS: Fabricated BCP showed well-distributed porosity. At 16 weeks, new bone formations were 45.26% (autogenous), 33.52% (MBCP), 24.34% (HA30), 19.43% (HA70) and 3.37% (negative). Residual material particles were 1.88% (autogenous), 17.58% (MBCP), 26.74% (HA30) and 37.03% (HA70). These values were not significant differences (Bonferroni correction <0.005). Bone-to-graft contacts were 73.68% (MBCP), which was significantly higher than 41.68% (HA30) and 14.32% (HA70; Bonferroni correction <0.017). CONCLUSIONS: Polymeric sponge technique offers well-distributed porosity. The new bone formation and residual material particles were comparable to MBCP+TM, but the bone-to-graft contact was lower than MBCP+TM.

Physical Properties of Glass Ionomer Cement Containing Pre-Reacted Spherical Glass Fillers.

The aim of this study was to assess the effect of different commercial liquid phases (Ketac, Riva, and Fuji IX) and the use of spherical pre-reacted glass (SPG) fillers on cement maturation, fluoride release, compressive (CS) and biaxial flexural strength (BFS) of experimental glass ionomer cements (GICs). The experimental GICs (Ketac_M, Riva_M, FujiIX_M) were prepared by mixing SPG fillers with commercial liquid phases using the powder to liquid mass ratio of 2.5:1. FTIR-ATR was used to assess the maturation of GICs. Diffusion coefficient of fluoride (DF) and cumulative fluoride release (CF) in deionized water was determined using the fluoride ion specific electrode (n=3). CS and BFS at 24 h were also tested (n=6). Commercial GICs were used as comparisons. Riva and Riva_M exhibited rapid polyacrylate salt formation. The highest DF and CF were observed with Riva_M (1.65x10-9 cm2/s) and Riva (77 ppm) respectively. Using SPG fillers enhanced DF of GICs on average from ~2.5x10-9 cm2/s to ~3.0x10-9 cm2/s but reduced CF of the materials on average from ~51 ppm to ~42 ppm. The CS and BFS of Ketac_M (144 and 22 MPa) and Fuji IX_M (123 and 30 MPa) were comparable to commercial materials. Using SPG with Riva significantly reduced CS and BFS from 123 MPa to 55 MPa and 42 MPa to 28 MPa respectively. The use of SPG fillers enhanced DF but reduced CF of GICs. Using SPG with Ketac or Fuji IX liquids provided comparable strength to the commercial materials.

Physical properties of glass ionomer cement containing pre-reacted spherical glass fillers

Abstract The aim of this study was to assess the effect of different commercial liquid phases (Ketac, Riva, and Fuji IX) and the use of spherical pre-reacted glass (SPG) fillers on cement maturation, fluoride release, compressive (CS) and biaxial flexural strength (BFS) of experimental glass ionomer cements (GICs). The experimental GICs (Ketac_M, Riva_M, FujiIX_M) were prepared by mixing SPG fillers with commercial liquid phases using the powder to liquid mass ratio of 2.5:1. FTIR-ATR was used to assess the maturation of GICs. Diffusion coefficient of fluoride (DF) and cumulative fluoride release (CF) in deionized water was determined using the fluoride ion specific electrode (n=3). CS and BFS at 24 h were also tested (n=6). Commercial GICs were used as comparisons. Riva and Riva_M exhibited rapid polyacrylate salt formation. The highest DF and CF were observed with Riva_M (1.65x10-9 cm2/s) and Riva (77 ppm) respectively. Using SPG fillers enhanced DF of GICs on average from ~2.5x10-9 cm2/s to ~3.0x10-9 cm2/s but reduced CF of the materials on average from ~51 ppm to ~42 ppm. The CS and BFS of Ketac_M (144 and 22 MPa) and Fuji IX_M (123 and 30 MPa) were comparable to commercial materials. Using SPG with Riva significantly reduced CS and BFS from 123 MPa to 55 MPa and 42 MPa to 28 MPa respectively. The use of SPG fillers enhanced DF but reduced CF of GICs. Using SPG with Ketac or Fuji IX liquids provided comparable strength to the commercial materials.

Resumo O objetivo deste estudo foi avaliar o efeito de diferentes fases líquidas comerciais (Ketac, Riva e Fuji IX) e o uso de partículas esféricas de vidro pré-reagido (SPG) na maturação do cimento, liberação de flúor, força de compressão (CS) e resistência biaxial à flexão (BFS) de cimentos de ionômero de vidro (GICs) experimentais. Os GICs experimentais (Ketac_M, Riva_M, FujiIX_M) foram preparados pela mistura de partículas SPG com fases líquidas comerciais usando a proporção de pó para massa líquida de 2,5: 1. O FTIR-ATR foi usado para avaliar a maturação dos GICs. O coeficiente de difusão do flúor (DF) e a liberação cumulativa de flúor (CF) em água deionizada foram determinados usando o eletrodo específico do íon fluoreto (n = 3). CS e BFS em 24 h também foram testados (n = 6). GICs comerciais foram usados como comparações. Riva e Riva_M exibiram rápida formação de sal de poliacrilato. Os maiores DF e CF foram observados com Riva_M (1,65x10-9 cm2/s) e Riva (77 ppm), respectivamente. O uso de partículas SPG melhorou o DF de GICs em média de ~ 2,5x10-9 cm2/s a ~ 3,0x10-9 cm2/s, mas reduziu o CF dos materiais em média de ~ 51 ppm a ~ 42 ppm. O CS e BFS de Ketac_M (144 e 22 MPa) e Fuji IX_M (123 e 30 MPa) foram comparáveis aos materiais comerciais. Usar SPG com Riva reduziu significativamente CS e BFS de 123 MPa para 55 MPa e 42 MPa para 28 MPa, respectivamente. O uso de SPG partículas melhorou o DF, mas reduziu o CF dos GICs. O uso de partículas SPG com líquidos Ketac ou Fuji IX proporcionou resistência comparável aos materiais comerciais.

Development of nanocomposite collagen/ HA/ß-TCP scaffolds with tailored gradient porosity and permeability using vitamin E.

The production of the biomimetic scaffolds with well-designed porosity parameters is a critical and challenging factor in biomaterials processing. The porosity parameters (i.e., pore size, pore shape, and distribution pattern) impact scaffold permeability, proteins/cells infiltration, and angiogenesis. This study introduced a new approach for the production of gradient porous nanocomposite scaffolds with controllable porosity and permeability using basic biomaterials of collagen and nanobiphasic calcium phosphate (nBCP) powder consisting of nano HA/ß-TCP. A modified freeze-drying method (i.e., variables; collagen/nBCP ratio and quenching rates) was integrated for the first time with the chemical foaming method with the use of vitamin E as a potential surfactant and porogen. Vitamin E successfully increased the range of pore size, pore interconnection, and scaffold permeability. Further control of collagen/nBCP ratios and quenching rates allowed modulation of the pore morphology, total porosity, and the surface roughness of the scaffold. Scaffolds produced using vitamin E with collagen/nBCP ratio of 92/8% at -80°C quenching rate displayed a multimodal heterogeneous pore network with a wide range of pore sizes of mostly round/oval and polygonal pore morphology. Furthermore, these scaffolds revealed a more consistent gradient porous network with peripheral large pores-that gradually become smaller toward scaffold central-that produced a significantly higher permeability and better support of initial cellular performances. Accordingly, considering the various potentials of vitamin E, this study would provide promising insight into the production of smart and customized scaffolds for regenerative and therapeutic applications.

The effect of powder to liquid ratio on physical properties and fluoride release of glass ionomer cements containing pre-reacted spherical glass fillers.

The aim was to assess the effect of powder to liquid ratio (PLR) on setting time, fluoride release, and compressive strength of conventional glass ionomer cements (GICs) containing pre-reacted spherical glass fillers (SPG). GICs were prepared by mixing SPG with Fuji IX Universal liquid using PLR of 1:1, 1.5:1, 2:1, 2.5:1, 3:1. Setting time decreased from 221 to 51 s upon rising PLR. Increasing PLR decreased cumulative fluoride release (33 to 13 ppm). Diffusion coefficient of fluoride of experimental GICs (1.6-1.8×10-8 cm2/s) was comparable with that of Fuji IX Universal (1.6×10-8 cm2/s). Compressive strength of PLR 2:1 to 3:1 (93-140 MPa) were comparable with that of Fuji IX Universal (124 MPa). These results demonstrated that rising powder ratio reduced setting time, fluoride release, and compressive strength of GICs. However, the setting time and strength experimental GICs with PLR greater than 2:1 were in the acceptable range of the ISO standard.

Integrated approach in designing biphasic nanocomposite collagen/nBCP scaffolds with controlled porosity and permeability for bone tissue engineering.

The bone scaffold for tissue engineering should be biomimetic, particularly in simulating the porosity features of natural bony tissue including pore size, pore shape, pore distribution pattern, and porosity percentage. Control of these can impact the scaffold hydrophilicity and permeability, which in turn influence the protein adsorption, cellular functions, and vascularization process. Various methods have been investigated for control of porosity parameters; however, the field still suffers from major challenges, that is, inadequate control of porosity and hydrophilicity at different levels. In this study, we developed an integrated approach for generation and control of porosity within nanocomposite collagen/nanobiphasic calcium phosphate (collagen/nBCP) scaffold. A modified freeze-drying procedure was applied alongside a chemical foaming method exploring the ability of "Tween 20" as a potent biocompatible porogen. Several processing variables were also examined including; quenching rate (-18 and -80°C), collagen/nBCP ratio (92/8% and 85/15%), and Tween ratio (10%, 20%, and 30%). Detailed physicochemical and porosimetry analysis confirmed the ability of Tween to actively modify the scaffold permeability and pore size by increasing the range of pore size while quenching rate mostly influenced the pore shape, and collagen/nBCP ratio affected total porosity and roughness. The collagen/nBCP ratio of 92/8% treated with low Tween ratios (10% and 20%) and exposed to -80°C quenching rate displayed more favorable physicochemical behavior, significantly higher permeability, a gradient porosity, and better in vitro performances. The proposed technique in this study provides an insight into the production of customized scaffolds for various tissue engineering applications.

Synthesis and characterization of biomimetic bioceramic nanoparticles with optimized physicochemical properties for bone tissue engineering.

Calcium phosphate bioceramics nanoparticles such as nano-hydroxyapatite (nHA) and nano-tricalcium phosphate (nTCP) are the main focus of basic and applied research for bone tissue regeneration. In particular, a combination of these two phases (nHA + nTCP) which refers to as "nano-biphasic calcium phosphates (nBCP)" is of interest due to the preferred biodegradation nature compared to single-phase bioceramics. However, the available synthesis processes are challenging and the biomaterials properties are yet to be optimized to mimic the physiochemical properties of the natural nanoscale bone apatite. In this study, a new approach was developed for the production of optimized bioceramic nanoparticles aiming to improve their biomimecity for better biological performances. Nanoparticles were synthesized through a carefully controlled and modified wet mechano-chemical method combined with a controlled solid-state synthesis. Different processing variables have been analyzed including; milling parameters, post-synthesis treatment, and calcination phase. Detailed physicochemical characterizations of nanoparticles revealed higher crystallinity (∼100%), lower crystallite/particle size (58 nm), higher homogeneity, reduced particle agglomeration size (6 µm), and a closer molar ratio (1.8) to biological apatite compared to control and standard samples. Furthermore, the study group was confirmed as calcium-deficient carbonate-substituted BCP nanoparticles (nHA/nß-TCP: 92/8%). As such, the introduced method can afford an easier and accurate control over nanoparticle physiochemical properties including the composition phase which can be used for better customization of biomaterials for clinical applications. The findings of this article will also help researchers in the further advancement of production strategies of biomaterials. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1654-1666, 2019.

Antiviral activity of multifunctional composite based on TiO2-modified hydroxyapatite.

An antiviral activity of TiO2-modified hydroxyapatite composite (HA/TiO2) had been investigated. The HA/TiO2 composite (HA50:Ti50) was prepared by a solid state reaction method followed by calcination at 650 °C for 2 h. Phase formations and morphologies of the obtained HA/TiO2 composite powders were determined using XRD and SEM. XRD result confirmed that HA/TiO2 composite was successfully prepared. SEM revealed small crystals of anatase TiO2 embedded in larger HA crystals. A strong antiviral activity against H1N1 Influenza A Virus was observed at 0.5 mg/ml concentration of the composite under the UV irradiation for 60 min. It showed the highest rate of reducing virus titer approximately more than 2 log/h. Results obtained from this study indicated that HA/TiO2 composite could be a promising material to be used as antimicrobial filtration applications such as in face masks.

Effects of polycaprolactone-biphasic calcium phosphate scaffolds on enhancing growth and differentiation of osteoblasts.

BACKGROUND: Polycaprolactone (PCL)-biphasic calcium phosphate (BCP) scaffolds fabricated using Melt-Stretching and Compression Molding (MSCM) can release calcium and phosphate ions, which are essential for bone formation. OBJECTIVE: Responses of the osteoblasts seeded on three groups of scaffolds including group A; PCL-20% BCP (%wt), group B; PCL-30% BCP and group C (control); pure PCL (100% PCL) were evaluated. METHODS: The cell-scaffold constructs were made by seeding osteoblast cell lines at 1×105 cells/scaffold. The constructs of each group were divided for culturing in proliferation medium (PR) and osteogenic induction medium (OS) for 30 days. RESULTS: The cells attached and grew on the scaffolds of all groups. The cell number and the differentiation markers of groups A and B were remarkably higher than those of group C over the observation periods. Slow proliferation of the cells of group A and B in the PR medium in the first 7 days corresponded to the maximum increases in alkaline phosphatase activities (ALP). The maximum levels of ALP of those groups in the OS medium were not detected until day 14. The levels of osteocalcin of those groups were not statistically different when cultured in both mediums. CONCLUSIONS: The MSCM scaffolds are suitable for supporting attachment and growth of the osteoblasts. Additional BCP into the PCL-based scaffolds accelerate early differentiation of the cells in the constructs even without osteogenic-inductive condition.

In vivo biocompatibility and degradation of novel Polycaprolactone-Biphasic Calcium phosphate scaffolds used as a bone substitute.

BACKGROUND: Biocompatibility and degradation of poly ε-caprolactone (PCL)-Biphasic Calcium Phosphate (BCP) scaffolds fabricated by the "Melt Stretching and Compression Molding (MSCM)" technique were evaluated in rat models. OBJECTIVES: Degradation behaviors and histological biocompatibility of the PCL-20% BCP MSCM scaffolds and compare with those of PCL-20% ß-tricalcium phosphate (TCP) scaffolds commercially fabricated by Fused Deposition Modeling (FDM) were evaluated. METHODS: The study groups included Group A: PCL-20% BCP MSCM scaffolds and Group B: PCL-20% TCP FDM scaffolds, which were implanted subcutaneously in twelve male Wistar rats. On day 14, 30, 60 and 90, dimensional changes of the scaffolds and their surrounding histological features were assessed using Micro-Computed Tomography (µ-CT) and histological analysis. Changes of their molecular weight were assessed using Gel Permeation Chromatography (GPC). RESULTS: Formation of collagen and new blood vessels throughout the scaffolds of both groups increased with time with low degrees of inflammation. The µ-CT and GPC analysis demonstrated that the scaffolds of both groups degraded with time, but, their molecular weight slightly changed over the observation periods. All results of both groups were not significantly different. CONCLUSIONS: The PCL-20% BCP MSCM scaffolds were biocompatible and biodegradable in vivo. Their properties were comparable to those of the commercial PCL-20% TCP scaffolds.

Properties of poly(lactic acid)/hydroxyapatite composite through the use of epoxy functional compatibilizers for biomedical application.

A composite of 70/30 poly(lactic acid)/hydroxyapatite was systematically prepared using various amounts of glycidyl methacrylate as reactive compatibilizer or Joncryl ADR®-4368 containing nine glycidyl methacrylate functions as a chain extension/branching agent to improve the mechanical and biological properties for suitable usage as internal bone fixation devices. The effect of glycidyl methacrylate/Joncryl on mechanical properties of poly(lactic acid)/hydroxyapatite was investigated through flexural strength. Cell proliferation and differentiation of osteoblast-like MC3T3-E1 cells cultured on the composite samples were determined by Alamar Blue assay and alkaline phosphatase expression, respectively. Result shows that flexural strength tends to decrease, as glycidyl methacrylate content increases except for 1 wt.% glycidyl methacrylate. With an addition of dicumyl peroxide, the flexural strength shows an improvement than that of without dicumyl peroxide probably due to the chemical bonding of the hydroxyapatite and poly(lactic acid) as revealed by FTIR and NMR, whereas the composite with 5 wt.% Joncryl shows the best result, as the flexural strength increases getting close to pure poly(lactic acid). The significant morphology change could be seen in composite with Joncryl where the uniform agglomeration of hydroxyapatite particles oriented in poly(lactic acid) matrix. Addition of the epoxy functional compatibilizers at suitable percentages could also have benefits to cellular attachment, proliferation, differentiation and mineralization. So that, this poly(lactic acid)/hydroxyapatite composite could be a promising material to be used as internal bone fixation devices such as screws, pins and plates.