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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.

Aim The aim of this study is to evaluate the effect on cell viability, the antibacterial activity against cariogenic bacteria, and the total bioavailability of commercially available children’s toothpastes in Thailand.Materials and methods Seven toothpaste slurries were prepared from seven commercial toothpastes for children. Total fluoride concentration was determined. Agar diffusion method was used to examine the antibacterial effect of toothpaste against Streptococcus mutans. The viability of L929 mouse fibroblasts exposed with different concentrations of each toothpaste slurry was tested by MTT assay.Results Fluoride concentration in fluoride containing toothpastes was ranged from 521.36 to 1377.83 ppm. Two toothpastes exhibited a similar level of fluoride concentration compared between the product labels. Other toothpastes showed the difference or slight difference in fluoride concentration between the companies’ information and our data. Zone of inhibition was ranged from 0-2.08 cm. Significant higher zone of inhibition was observed in toothpastes with sodium lauryl sulphate. The concentration of toothpaste that reduced cell viability to be less than 50% of the control was 0.8%, 3.1%, 6.3%, 6.3%, 25% and 100% for Fluocaril Deli Fruity, Oral-B Junior 6+, Kodomo kids, CUdent Stevia, Sun Star GUM and Kindee Organic, respectively.Conclusion The examined children’s toothpastes can inhibit the growth of S. mutans which did not correlate with fluoride concentration. The antibacterial effects could be the results of other ingredients, for example sodium lauryl sulphate.

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.

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, β-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.

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.

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.

The objective of this study was to evaluate the antibacterial properties and pH changes of bioactive glasses and zinc oxide nanowire in different concentrations. Bioactive glasses (45S5 and 45S5F) were prepared in three concentrations of 10, 20, and 50 mg/ml and zinc oxide nanowire was prepared in 1 and 5 mg/ml concentrations. The materials were exposed to 500 ml brain heart infusion broth (BHI) with 1.5 x 107 of S.mutans and S.sanguinis separately. Antibacterial properties were tested indirectly by collecting 100 ml of each sample and transferred into a 96 well-plate. The optical density (OD) was evaluated using spectrophotometry at 630 nm at 24h and 48h. The pH changes were recorded. The data were statistically analyzed by Kruskal-Wallis tests. The result showed that the pH changes were significantly different in the Bioactive glass samples, while zinc oxide nanowire showed stable pH. Antibacterial activity against S.mutans was significant lower for 45S5 at 50 mg/ml, 45S5F and zinc oxide nanowire in all concentrations at 24 h. While in 48 h, 45S5, 45S5F and zinc oxide nanowire showed significant antibacterial activity in all concentration except 45S5F at 10 mg/ml. Antibacterial activity against S.sanguinis was significant for 45S5 and 45S5F at 20 and 50 mg/ml and zinc oxide nanowire in all concentration at 48h. It can be concluded that Bioactive glasses (45S5 and 45S5F) exhibited antibacterial properties and pH changes depending on its concentration, while zinc oxide nanowire exhibited antibacterial properties at low concentrations with a constant pH value.

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/β‐TCP70 (HA30) and HA70/β‐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

Background Reusing N95 respirators with a practical and easy decontamination protocol might be a solution for the shortage of N95 respirators. We aimed to study the reliability and safety of household UV-C devices for the decontamination of N95 respirators. Methods We investigated a baby bottle ultraviolet C (UV-C) sterilizer box for N95 decontamination. Swine coronavirus (PEDV) was sprayed on the N95 and the virus was cultivated after UV-C sterilization. Bacterial culture from used N95 respirator was performed before and after UV-C exposure. Scanning electron Microscopy (SEM) was used to observe the structural change after UV-C exposure. The radiation was measured by radiometer. The fit test was performed on 3 participants before use, and after reuse 4 and 6 times. Results The PEDV sprayed on the N95 respirator was inactivated by the UV-C level of 0.930–0.932 mW/cm2. Nearly all bacterial colonies had disappeared after the 10 min of the UV-C exposure. No significant change to the structure of the N95 polymer fibers after 240 min of UV-C exposure was observed by SEM. Three and two participants passed the fit test after the fourth and sixth time of reuse, respectively. Conclusions During the COVID-19 pandemic crisis, UV-C products may be practical and safe options for decontaminating N95 respirators, if the energy of UV-C is in the range known to deactivate the virus.

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.

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.

Background Biocompatibility and degradation of poly e-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% β-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.

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.

Calcium phosphate cements (CPCs) have been extensively used as bone graft substitutes for the repair of bone defect due to its biocompatibility, osteoconductivity and in-situ setting capability. They poorly degrade thus limiting their use in tissue engineering application. A possible strategy to improve the speed of CPC degradation is to add porogen to CPC to create macropores that can enhance cement resorption and can consequently be replaced by new bone. The as-generated macropores are generally not connected because of spherical shape of the porogens which can limit the extent of newly formed bone. The aim of this study was to fabricate CPCs having tubular macroporous structure by incorporating fast-dissolving maltodextrin microstrips (MDMS) and explore their properties such as setting time, mechanical property, microstructure and degradability of the cements. The results showed that after immersing MDMS-embedded composites in simulated body fluid under physiological condition for 1 d MDMS rapidly disintegrated (more than 70%), generating tubular macropores in CPCs. The disintegration of MDMS completed in 1 week. CPCs containing MDMS lower than 30% by weight had the same final setting time as those without MDMS. The average values of compressive strength of the CPC composites decreased with the disintegration of MDMS. % Porosity and pore interconnectivity increased with increasing MDMS content. In addition, MDMS-embedded CPCs were cell friendly with excellent cell adhesion, indicating a possible candidate as bone graft substitutes.

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/β-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 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.

Physical properties and biocompatibility of polycaprolactone (PCL)–biphasic calcium phosphate (BCP) scaffolds fabricated by the modified melt stretching and multilayer deposition (mMSMD) technique were evaluated in vitro. The PCL–BCP scaffold specimens included group A; PCL: BCP (wt%) = 80:20 and group B; 70:30. Mechanical properties of the scaffolds were assessed using a universal testing machine. Degradation behaviors of the scaffolds were assessed over 60 days. The amount of calcium and phosphate ions released from the scaffolds was detected over 30 days. Attachment and growth of osteoblasts on the scaffolds and indirect cytocompatibility to those cells were evaluated. The results showed that the scaffolds of both groups could withstand compressive forces on their superior aspect very well; however, their lateral aspect could only withstand light forces. Degradation of the scaffolds over 2 months was low (group A = 1.92 ± 0.47% and group B = 2.9 ± 1.3%, p > 0.05). The concentrations of calcium and phosphate ions released from the scaffolds of both groups significantly increased on day 7 ( p

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/nβ-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.

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Purpose: This study aimed to evaluate the effect of biphasic calcium phosphate (BCP) with high hydroxyapatite/tricalcium phosphate (HA/TCP) ratios on bone formation in rabbit calvarial defects. Materials and Methods: Sixteen New Zealand white rabbits were randomly divided into two groups, a control group and an experimental group. In each animal, bilateral circular defects (10-mm diameter) were created on the calvarium. In the control group (three rabbits per time frame), defects were grafted with autogenous bone chips in one side and left empty in the other side. In the experimental group (five rabbits per time frame), defects were grafted with BCP1 (HA:TCP, 8:2) in one side and BCP2 (HA:TCP, 9:1) in the contralateral side. The animals were sacrificed at 2 and 8 weeks as designated. Bone formation and residual grafting material were assessed by radiographic densitometry, microcomputed tomography (micro-CT), and histomorphometric analysis. Results: Histologic observation revealed that BCP1, BCP2, and the autogenous bone group preserved good contours of the defect, while the unfilled defect group showed connective tissue healing. Micro-CT analysis at 8 weeks showed the comparable percentages of bone volume fraction (% BV/TV) of BCP1 (20.70% ± 2.76%) and BCP2 (20.72% ± 3.97%) and two times higher than that of 2 weeks (9.90% ± 0.75%, 10.57% ± 0.85%). The autogenous group had a significantly (P < .005) greater % BV/TV (34.58% ± 8.85%) than other groups. The percentage of the material volume fraction of BCP1 and BCP2 was not different. The histomorphometry demonstrated a higher increase in newly formed bone from 2 to 8 weeks in all groups, and all were comparable (autogenous: 4.30% ± 0.76%, 12.83% ± 7.74%; unfilled: 2.82% ± 1.19%, 8.14% ± 6.35%; BCP1: 3.01% ± 2.57%, 8.81% ± 3.86%; BCP2: 3.24% ± 1.09%, 10.27% ± 3.98%). Conclusion: BCP with a high ratio of HA presented good osteoconductive properties and space-maintaining capacity and would be beneficial for long-term preservation or when stable graft volume is essential.

This study investigated the shear bond strength (SBS) between veneering porcelain and zirconia substructure using lithium disilicate glass-ceramic as a liner. The mineral phases and microstructures of lithium disilicate glass-ceramic at temperature range of 800-900°C were preliminarily investigated. SBSs of porcelain-veneered zirconia specimens with and without lithium disilicate glassceramic liner fired at the same temperature were determined. Results showed that SBSs of veneering porcelain and zirconia with lithium disilicate glass-ceramic liner was notably increased (p

Honeycomb structures of TiO2-modified hydroxyapatite composite (HA/TiO2) were fabricated using extrusion technique. The mixture formulations of HA/TiO2 extrusion pastes (S1-S4) were investigated to optimize the process. The filtering effectiveness of the HA/TiO2 honeycombs was evaluated by photocatalytic activity measurement and a bactericidal test. The effects of sintering temperature and honeycomb thickness on photocatalytic and antibacterial activities were additionally studied. The S3 and S4 honeycomb samples, sintered at 650°C, exhibited a similar trend in reducing methylene blue concentration. At 800°C, the S3 honeycomb sample showed a slightly faster reduction in methylene blue concentration compared to the S4 honeycomb. Honeycomb samples of 2 and 5 cm in thickness showed significantly greater photocatalytic activity than that of 1 cm such that methylene blue concentrations rapidly decreased after UV exposure for 24 hours. The S3 and S4 honeycomb samples also exhibited decomposition of both gram-negative E. coli and gram-positive S. aureus. Approximately 50% of gram-positive S. aureus and gramnegative E. coli were decomposed by the honeycombs in the sample-thickness dependent manner after 2 hours of UV exposure. Low survival ratios of bacteria (5% - 10%) were observed after 6 hours of UV exposure and the 2 mm and 5 mm thick honeycomb samples showed the greatest and most similar antibacterial activities.