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Objectives This study evaluates the difference in physical and mechanical properties of ZrO2 ceramics, commonly used in dental applications, altered by three different forms of Al2O3 content; microparticles (m), nanoparticles (n), and microfiber (f). Methods Three different types of ZrO2–Al2O3 composites were formed using microparticle (m), nanoparticle (n), or microfibre (f) forms of Al2O3. The physical and mechanical properties such as sintering shrinkage, relative density, Vickers hardness, fracture toughness, and biaxial strength were evaluated. A Weibull analysis was performed to assess the strength reliability of the specimens. All data were calculated using the t-test and ANOVA. Results The sintering shrinkage and relative density of all ceramic composite groups were decreased with the addition of Al2O3. The mechanical properties of ZrO2–Al2O3 (f) composite were higher than that of ZrO2–Al2O3 (m) composite and ZrO2–Al2O3 (n) composite. The maximum hardness, fracture toughness, and biaxial flexural strength were observed for 10 vol% of Al2O3 fibre. When the content of Al2O3 fibre in the matrix was increased above 20 vol%, agglomeration occurred and resulted in a decrease of hardness and toughness. The Weibull modulus value of the ZrO2–Al2O3 (f) composite was the lowest compared to that of other groups. However, characteristic strength (σ0) of ZrO2–Al2O3 (f) the highest value. Significance The current study demonstrated that the addition of right amount of Al2O3 microfibre into the ZrO2 matrix enhanced the mechanical properties of ZrO2-Al2O3 (f) composite, which would be favourable for dental applications.

Poly (methyl methacrylate) (PMMA) is a commonly used material for the fabrication of biomedical appliances. Although PMMA has several advantages, it is susceptible to microbial insults with practical use. Therefore, different bioactive nanomaterials, such as nanoceria (CeN), have been proposed to enhance the properties of PMMA. In this study, we investigated the effect of the incorporation of CeN into PMMA with and without the use of mesoporous silica nanoparticle (SBA-15) carriers. The unmodified PMMA specimens (control, CTRL) were compared to groups containing SBA-15, CeN, and the synthesized SBA-15 impregnated with CeN (SBA-15@CeN) at different loading percentages. The mechanical and physical properties of the different SBA-15@CeN groups and their effects on cell viability were investigated, and the optimal CeN concentration was identified accordingly. Our results revealed that flexural strength was significantly (P 0.01) reduced in the SBA-15@CeN

This study evaluated the synergetic effect between surface pre-reacted glass-ionomer (SPRG) filler and 2-methacryloyloxyethyl phosphorylcholine (MPC), for inhibiting multi-species biofilm formation, while maintaining or even improving the original beneficial features of SPRG-filled resin-based composite (RBC).MPC (1.5-10wt%) was incorporated into commercial SPRG-filled RBC. Then, the inherent properties of RBC, and ion release and acid-neutralising properties associated with SPRG were investigated. Further, protein adsorptions and bacterial adhesion and viability on the SPRG-filled RBC surfaces were studied using four kinds of oral bacteria; Streptococcus mutans, Actinomyces naeslundii, Veillonella parvula, and Porphyromonas gingivalis. Finally, the thickness and biomass of the human saliva-derived biofilm model cultured on test and control samples were analysed.Addition of MPC content resulted in decreased flexural strength and wettability of SPRG-filled RBC. SPRG-filled RBC released significantly higher amounts of multiple ions as contents of MPC increased. Meanwhile, SPRG-filled RBC with 5-wt% MPC significantly improved acid-neutralising properties than those of other test and control samples (P0.001). SPRG-filled RBC with 3wt% MPC significantly reduced the amount of adsorbed bovine serum albumin and proteins from the brain heart infusion medium as compared to the control (P0.01). A similar trend was observed in the attachment of four types of bacteria and multi-species biofilm (P0.01).Despite limitation in terms of deteriorations of some physical properties, addition of 3% MPC to SPRG-filled RBC leads to inhibition of the attachment of multi-species bacteria on its surface, as well as inhibition of biofilm growth. Moreover, the original important bioactive features of SPRG-filled RBC such as ion release and acid neutralisations are either maintained or improved upon adding MPC.

Considering the inferior mechanical properties of the current bioresorbable polymers, a novel bioresorbable magnesium-reinforced polylactide (PLA) membrane was designed for the application in critical defect sites in guided bone/tissue regeneration. The PLA-FAZ91 membrane was fabricated by combining two PLA membranes with a fluoride-coated AZ91 (9 wt% Al, 1 wt% Zn) (FAZ91) magnesium alloy core by hot pressing. A combined double-layered PLA membrane was used as the control group. A three-point bending test was performed to compare their maximum load and stiffness. Samples were immersed in the HBSS for 20 weeks, and their weight loss percentages were recorded, and a three-point bending test was performed after immersion. An ion release test was performed by immersing samples in the HBSS for 4 weeks and determining the pH and ion concentrations of the HBSS. Cell viability was tested by culturing pre-osteoblast cells with sample extracts in the culture medium obtained from degraded samples. As a result, PLA-FAZ91 showed a significantly higher maximum load and stiffness than those of the non-reinforced PLA membrane. The weight loss of PLA-FAZ91 was much faster, as FAZ91 showed major degradation and was completely degraded after 16–20 weeks of immersion. The degradation of the PLA wrap was accelerated by FAZ91. The mechanical superiority of PLA-FAZ91 over PLA endured for at least 3 weeks during immersion. The pH, magnesium- and fluoride-ion concentration in the PLA-FAZ91 group increased at an appropriate rate. The cell viability was not adversely affected by the addition of FAZ91 to PLA. Therefore, the bioresorbable magnesium-reinforced PLA membrane has the potential to be used as a good alternative to pure PLA membrane in guided bone/tissue regeneration.

Even though roughened titanium (Ti) and Ti alloys have been clinically used as dental implant, they encourage bacterial adhesion, leading to failure of the initial stability. Here, the non-thermal atmospheric pressure plasma jet (NTAPPJ) functionalized Ti and Ti alloy were investigated to promote cellular activities but inhibit the initial attachment of the adherent pioneer bacterium, Streptococcus sanguinis, without topographical changes.After the produced radicals from NTAPPJ were characterized, bacterial adhesion to specimens was assessed by PrestoBlue assay and live-dead staining with or without the NTAPPJ functionalizing. After the surface was characterized using optical profilometry, X-ray photoelectron spectroscopy and contact angle analysis, the ions released from the specimens were investigated. In vitro initial cell attachment (4h or 24h) with adhesion images and alkaline phosphatase activity (ALP, 14 days) measurements were performed using rat bone marrow-derived mesenchymal stem cells.The initial bacterial adhesion to the Ti and Ti alloy was significantly inhibited after NTAPPJ functionalizing (p0.05) compared to those without NTAPPJ functionalizing. The bacterial adhesion-resistance effect was induced by carbon cleaning, which was dependent on the working gas used on the Ti specimens (nitrogenammonia and air, p0.05). The initial cell adhesion with well-developed vinculin localization and consequent ALP activity at 14days to the NTAPPJ-functionalized specimens were superior to the non-treated specimens.For the promising success of dental implants, NTAPPJ functionalizing is suggested as a novel surface modification technique; this technique can help ensure the success of integration between the dental implants and bone tissues with less concern of inflammation.

Objective The main goal of this research was to demonstrate the potential value of boron nitride nanoplatelets (BNNPs), which have excellent mechanical properties and biocompatibility, as a suitable reinforcement for dental materials. Methods The BNNPs were prepared by exfoliating h-BN via high-energy ball-milling and dispersion on a zirconia matrix. Then the composite powder was consolidated using spark plasma sintering. Fracture toughness, flexural strength and wear resistance were the mechanical properties explored. Agar diffusion-based biocompatibility testing was carried out. Low temperature degradation tests were also performed in a steam environment in an autoclave. Results The BNNPs dispersed zirconia exhibited improved strength (up to 27.3%), and fracture toughness was also increased (up to 37.5%) with the addition of 1–1.5 vol.% BNNPs. Tribological properties were also enhanced by the addition of BNNPs. The cytotoxicity tests confirmed that the BNNPs do not have obvious toxicity. The accelerated low-temperature degradation experiment revealed the barrier properties of the BNNPs, whose addition almost fully inhibited the degradation of the zirconia matrix in a humid environment. Significance The main contribution of this study is the introduction of an advanced material, BNNP, which can be used as a biocompatible reinforcement for dental materials, resulting in enhanced mechanical properties of the system due to its unique structure and extraordinary properties.

Objectives The objective of this study is to assess the cytotoxic and anti-inflammatory effects of ZOE cement during setting in two-dimensional (2D) or three-dimensional (3D) cultures of immortalized human oral keratinocytes (IHOKs) with determining the extract components responsible for these effects. Methods Extracts of mixed ZOE at different stages of setting were analyzed by a digital pH meter, ICP-MS, and GC–MS. Serial concentrations of extract and their mixture of ZnCl 2 , ZnSO 4 ·H 2 O, and eugenol liquid were added to the 2D and 3D IHOK cultures to determine the half maximal effective concentration in investigating the cause of cytotoxicity by means of WST assay and to investigate mRNA expression levels of inflammatory cytokines by RT-PCR. Results Zn 2+ and eugenol (4–19 ppm) were detected in the extracts. In the early setting stage, significant cytotoxicity was observed in the 2D and 3D IHOK cultures ( P 2+ from ZnCl 2 was 5–44 ppm in both cultures, whereas the EC50 of eugenol was not detectable under 100 ppm. Along with the lower levels of inflammatory cytokine gene expressions in the extract, treatment of the 2D IHOKs with Zn 2+ alone and treatment of the 3D IHOKs with Zn 2+ plus eugenol resulted in significantly lower expression levels of IL-1β, IL-6, and IL-8 ( P Significance The cytotoxic effect of ZOE on IHOKs was greater during the setting stage owing to the presence of Zn 2+ . The anti-inflammatory response to ZOE was induced by a combination of Zn 2+ and eugenol. Cytotoxic and anti-inflammatory effects differed between the 2D and 3D IHOK cultures.

The aim of this study was to evaluate whether combining two treatments to avoid biological aging of the surface of titanium and zirconia implants; i.e., storage in an aqueous solution after ultraviolet light (UV) or non-thermal atmospheric pressure plasma (NTP) treatment, yielded surface bioactivity comparable to that following post-15-min UV or NTP treatment storage under air or immediately after UV or NTP treatment. Grade IV titanium discs modified by large grit sand-blasting and acid-etching (SLA) and smooth zirconia discs were irradiated with UV or NTP and their surface properties were evaluated immediately and after storage for 8 weeks in distilled H2O (dH2O) and a sealed container under air. Approximately 15–30 nm-sized nano-protrusions were formed only on SLA surfaces in dH2O immediately after UV or NTP treatment. Immediate dH2O storage after UV or NTP treatment prevented hydrocarbon contamination and maintained elevated amounts of Ti and Zr. After 8 weeks, unlike zirconia, protein adsorption, cellular adhesion, and cytoskeletal development of MC3T3-E1 cells on SLA surfaces stored in dH2O immediately after UV treatment were further exceeding those immediately after UV or NTP treatments. UV treatment of SLA implants followed by wet storage can not only maintain but also strengthen bioactivity during shelf storage.

Dental alloys containing indium (In) have been used in dental restoration for two decades; however, no study has investigated the biological effects of In ions, which may be released in the oral cavity, on human oral keratinocytes. The objective of the present study was to investigate the biological effects of In ions on human oral keratinocyte after confirming their release from a silver-palladium-gold-indium (Ag-Pd-Au-In) dental alloy.As a corrosion assay, a static immersion tests were performed by detecting the released ions in the corrosion solution from the Ag-Pd-Au-In dental alloy using inductively coupled plasma atomic emission spectroscopy. The cytotoxicity and biological effects of In ions were then studied with In compounds in three human oral keratinocyte cell lines: immortalized human oral keratinocyte (IHOK), HSC-2, and SCC-15.Higher concentrations of In and Cu ions were detected in Ag-Pd-Au-In (P0.05) than in Ag-Pd-Au, and AgCl deposition occurred on the surface of Ag-Pd-Au-In after a 7-day corrosion test due to its low corrosion resistance. At high concentrations, In ions induced cytotoxicity; however, at low concentrations (∼0.8In(3+)mM), terminal differentiation was observed in human oral keratinocytes. Intracellular ROS was revealed to be a key component of In-induced terminal differentiation.In ions were released from dental alloys containing In, and high concentrations of In ions resulted in cytotoxicity, whereas low concentrations induced the terminal differentiation of human oral keratinocytes via increased intracellular ROS. Therefore, dental alloys containing In must be biologically evaluated for their safe use.

Objective We evaluated whether the biological activity of the surface of titanium, when stored in an aqueous solution, in low vacuum, and under ambient conditions after ultraviolet light (UV) treatment is comparable to that of the surface immediately after UV treatment for 15 min and that after dielectric barrier discharge (DBD) plasma treatment for 15 min. Methods Grade IV titanium discs with machined surfaces were irradiated with UV and their surface properties were evaluated immediately and after storage for 28 days in distilled H 2 O (dH 2 O), a vacuum desiccator (31.325 kPa), and a sealed container under air. Their surface characteristics were evaluated by atomic force microscopy, X-ray diffraction, contact angle analysis, and X-ray photoelectron spectroscopy. Biological activities were determined by analyzing the albumin adsorption, MC3T3-E1 cell adhesion, and cytoskeleton development. Results Hydrophilicity of titanium surfaces stored in dH 2 O was comparable to that immediately after UV treatment and higher than that immediately after DBD plasma treatment ( P 0.001). Storage in dH 2 O and in low vacuum immediately after UV treatment prevented hydrocarbon contamination and maintained elevated amounts of titanium and oxygen. After 28 days, protein adsorption, cellular adhesion, and cytoskeletal development of MC3T3-E1 cells on the titanium surfaces stored in dH 2 O were significantly enhanced compared to those stored in low vacuum and under ambient conditions while being comparable to those immediately after UV and DBD plasma treatments. Significance UV treatment of the titanium implants followed by wet storage is useful for maintaining enhanced biological activity and overcoming biological aging during shelf storage.

The purpose of this study was to investigate the antibacterial effect of sand-blasted, large-grit, acid-etched (SLA) treated Ti–Ag alloys. Three different alloys with varying Ag contents (Ti–1Ag, Ti–2Ag, and Ti–4Ag) were SLA treated by grit blasting with 250 μm sized alumina and acid-etching in 7% HCl + 27% H 2 SO 4 solution at 110 °C for 5 min. The microporous structures were formed following SLA treatment and Ag particles were identified on Ti–2Ag and Ti–4Ag alloys. And high concentration of Ag released steadily during 7 days from the Ti–4Ag. Higher level of antibacterial effect was evident on SLA treated Ti–Ag alloys compare to commercially pure Ti ( p Streptococcus aureus whereas no significant difference in cell viability among the SLA treated Ti–Ag allows and commercially pure Ti was identified. Hence, it was concluded that SLA treated Ti–Ag had an antibacterial effect while being biocompatible.

article i nfo Article history: Received 3 May 2010 Accepted 23 July 2011 Available online xxxx In this study, the whitening effect of simulated body fluid (SBF) and side effects of a hydrogen peroxide (H2O2) as the bleaching treatment of tooth enamel surfaces was investigated. H2O2 solution of 25% and 30% was prepared by diluting the commercially available 35% H2O2 solution with either distilled water (DW) or SBF of 1×, 3×, and 5× concentrations. These diluted H2O2 solutions were applied to the dental enamel surface of eighty human premolars for 15 min, followed by rinsing with DW. The procedure was repeated 4 times. The changes in color and surface microhardness before and after the bleaching procedure were recorded. The enamel surfaces of bleached teeth were examined with SEM. The results indicated that the brightness and microhardness of the tooth surface increased after bleaching with the SBF diluted agent compared to teeth treated with the DW diluted agent. These results might be due to the deposition of bone-like apatite that was observed with SEM. This bone-like apatite fills the area of roughness and holes in the enamel surfaces that were caused by bleaching, and created smoother and harder enamel surfaces. The result of this study suggested that a bleaching agent comprised of hydrogen peroxide and SBF would prevent the destructive side effects of bleaching and increase surface microhardness as well as having a whitening effect.

Carbonate apatite has a similar structure to the inorganic component of teeth and bone. Although carbonate apatite is widely used as a bone substitute, there are no reports on its use as a desensitizing dentifrice. This in vitro study evaluated the relative abrasivity of the dentifrice containing nano-sized carbonated apatite (n-CAPs) using a Surface Profile Method (SPM). The dentin specimens were made from the root of extracted human molars. The cervical part of the teeth was sectioned with a diamond wheel disk. The teeth were embedded into an epoxy resin mold and the surface was gradually polished using silicone carbide paper. After grinding, the degree of surface roughness was examined within the range of 2 mm with tapping. The British Standard Institution reference dentifrice (BSI: CaCO3 40%) and the experimental dentifrices (group 1: n-CAPs 30%, group 2: n-CAPs 15% and silica 15%, group 3: n-CAPs 5% and silica 25%, group 4: silica 30%, group 5: CaCO3 10% and SrCl2 10%) were compared. The dentifrice slurries were prepared by mixing 24 grams of the dentifrice in 12 ml distilled water. Each tooth specimen was brushed 1,000 times with the dentifrice slurries using a back-and-forth stroke. The relative abrasivity of each dentifrice was evaluated by determining the ratio of the BSI standard dentifrice to each experiment. The results were analyzed using one-way ANOVA and Tukey’s multiple comparisons using Window SPSS (Statistical analysis system) 12.0. According to the results, Group 1 (3.2), which contained only n-CAPs appeared to have the lowest abrasivity than the BSI dentifrice (100). However, Groups 2 (124.2), 3 (137.9) and 4 (178.1), which contained n-CAPs and silica, appeared to have a higher abrasivity than the BSI dentifrice (p>0.05). The relative abrasivity of group 5 (38), which was a commercial desensitizing dentifrice, was relatively lower. It appears that the higher abrasivity of the experimental is due to the shape and size of the silica component. Therefore, n-CAPs itself has no influence on the abrasivity of the dentifrice. The main reason for the low abrasivity of n-CAPs is believed to be its small particle size (range 50-90nm).

The main objective of this study was to manufacture an oral rinse using the natural antibacterial agent (phytosphingosine, Doosan, Korea) for the prevention of periodontal disease and dental caries. Phytosphingosine is known to inhibit the growth of bacterial strains and induce apoptotic cell death in human cancer lines. In this study, antibacterial activity and cytotoxicity of oral rinses were performed with an experimental group containing phytosphingosine(PS) in vitro. Control groups consist of two Korean products and two American products containing chlorhexidine and cetylpyridinium chloride, respectively. There was no significant difference between experimental and control groups in the antibacterial activity and cytotoxicity except for Chika Chika Liq (p

The titanium oxide layer with nano–micro hybrid structure on the titanium substrate was formed by grit-blasting and anodic oxidation treatment. A micro rough surface can be formed by grit-blasting and nanotube arrays can be formed by anodic oxidation or NaOH treatment after anodic oxidation. We investigated the surface characterization on titanium and the response of the osteoblast like cell (MG-63) to the surfaces made by different treatments. Surface structure (morphology), wettability characterized by SEM, contact angle. The attachment and proliferation behavior of MG-63 cells on the titanium surface by different surface treatments were characterized by SEM observation and MTT assay.The attachment and proliferation of osteoblast cells is accelerated by the topography of the nano structure like a nanotube, the nano surface acts as an attachment point for the filopodia of growing cells. Nano structure increases surface area and nano-micro structure significantly increases surface area. Such nano–micro hybrid structure on the titanium substrate can be useful for a well-adhered bioactive surface layer on Ti implant used metals for orthopedic and dental implants.

The 2% NaF and 8% SnF2 have been used in topical fluoridation method in the dental office to increase the resistance of enamel to acid dissolution. Bis-GMA based monomers have been used for the basic materials in the dental pit and fissure sealants. Therefore, the resinous pit and fissure sealant including fluorides may increase the effect of preventing dental caries. In this study, we made a novel dental pit and fissure sealant and evaluated some properties, especially fluoride release. In order to make experimental pit and fissure sealant including fluoride, NaF and SnF2 powder were added into self-made monomer composed of Bis-GMA, TEGDMA, UDMA and photo initiator system by weight percent of 2% and 8% respectively. The just monomer without fluoride powder was used for control. Uncured film thickness and depth of cure were measured according to ISO specification 6874:1988 and the viscosity was measured using rheometer. The five disc specimens were made using light curing unit to evaluate fluoride releasing and each specimen was immersed in the artificial saliva of 10 mL. Fluoride ion concentrations in extracts were measured for 3 days using fluoride electrode at every 12 hrs. There was no significant difference between experimental and control group in the depth of cure, uncured film thickness, and viscosity (p>0.05). The released fluoride ion concentration was continuously retained for 72 hrs.

This study examined the possibility of synthesis of biphasic calcium phosphate by sintering a mixture of hydroxyapatite and calcium phosphate glass. The effect of the concentration of calcium phosphate glass in a mixture on the proliferation and differentiation of MG-63 preosteoblast-like cells in a hydtoxyapatite scaffold was investigated. The addition of 5 wt% of calcium phosphate glass significantly improved the level of attachment, proliferation and differentiation of MG-63 cells onto the hydroxyapatite scaffolds, particularly when the surface was modified with 2% bovine serum albumin (p

In this study, the effect of cyanoacrylate-based β-tricalcium phosphate (β-TCP) on pullout strength of orthodontic mini-screw was evaluated. New cements were prepared by mixing Histoacryl® (n-butyl cyanoacrylate) and acid-treated β-tricalcium phosphate. The ratios of β-TCP to Histoacryl® were 0, 0.5, 1.0, and 2.0. Artificial bone blocks were used as a substrate for the miniscrew implantation. The test groups were divided into three groups (one solid bone block [group 1] and a bone block with a 0.9 mm hole [group 2], and a bone block with a 2.5 mm hole [group 3]). And each group was divided into subgroups according to cement usage and non-usage. The used artificial bone density was 0.64g/cm2. Pullout strengths were determined using a universal testing machine. Statistical analysis was performed using the SPSS 9.0 for Windows program. Paired samples t-tests and ANOVA were used with p

The purpose of this study was to evaluate the shear bond strength of composite resin to 4 different all-ceramic coping materials with 3 different surface treatments after thermocycling and without thermocycling. Three different surface treatments - sandblasting with 50 ㎛ alumina particles (AB); sandblasting with 50 ㎛ alumina particles and acid etching with 4% hydrofluoric acid (AE); sandblasting with 50 ㎛ alumina particles and 30 ㎛ alumina particles with tribochemical silica coating (SI) and silane application - were used on four different all-ceramic; Feldspatic ceramic (Duceram Plus); Lithium disilicate ceramic (IPS Empress2); Alumica ceramic (In-Ceram Alumina); Zirconia ceramic (Zi-Ceram) - substrates. Shear bond strength of restorative composite resin to substrate was tested after thermocycling and without thermocycling (n=10). Each specimen was subjected to a shear load at a crosshead speed of 2 ㎜/min until fracture. Two-way analysis of variance and Duncan multiple comparison test (α =0.05) were used to analyze the bond strength values. There were significant differences in the bond strengths for ceramic types (P

In this study, the effects of bracket designs and force direction on fracture strength of alumina bracket were evaluated. Two differently designed alumina brackets (MISO, HT Co., Ltd., Seoul, Korea) were tested. Each bracket was bonded with orthodontic adhesive to stainless steel cylinder. Compressive force was applied to the tie wing of bracket at 30°, 60°, and 90° to the long axis of the test device. Fracture strengths were assessed by using a universal testing machine (Instron 3366, Instron Co., Ltd., U.S.A.). Fractured bracket surfaces were examined using SEM. Statistical analysis was performed by using SPSS 9.0 for Windows program. Paired samples t-tests and Kruskal-wallis tests were used at P

This in vitro study compared the abrasivity of commercial desensitizing dentifrices with a sodium metasilicate (Na2SiO3) dentifrice using a Surface Profile Method. Dentin specimens were made from the root of extracted human molars. The cervical part of the teeth was sectioned with a diamond wheel disk. The teeth were embedded into an epoxy resin mold and the surface was gradually polished by silicone carbide paper. After grinding, the degree of surface roughness was tested within the range of 2 mm with tapping. The British Standard Institution reference dentifrice (BSI: CaCO3 40%) and experimental dentifrices (group 1: Na2SiO3 25%, CaCO3 10% and SiO2 10%, group 2: CaCO3 10% and SiO2 10%, group 3: CaCO3 10% and SrCl2 10%, group 4: Colloidal Silica 2-3% and Hydroxyapatite 10-20%) were evaluated. The dentifrice slurries were prepared by mixing 24 grams of the dentifrice in 12 ml distilled water. Each tooth specimen was brushed with the dentifrice slurries 1,000 times. The relative abrasivity of each dentifrice was evaluated from the ratio of the BSI standard dentifrice to each experiment. The results were analyzed by one-way ANOVA and Tukey’s multiple comparisons using Window SPSS (Statistical analysis system) 12.0. Groups 1 (71), 2 (74.2), 3 (38) and 4 (7.8) showed a lower abrasivity than the BSI dentifrice (100) (p0.05). Therefore, Na2SiO3 had no influence on the abrasivity of the dentifrice. In conclusion, the dentifrice containing Na2SiO3 had a lower abrasivity than the BSI reference dentifrice, but showed a significantly higher abrasivity than the existing commercial desensitizing dentifrices. Overall, the relatively high abrasivity of Na2SiO3 dentifrice is believed to be the result of other components in the abrasive system.

The purpose of this study was to compare the bone regenerative effect of calcium phosphate glass according to the particle size in vivo. We prepared two different sizes, that is 400 μm and 40 μm, of calcium phosphate glass powder using the system CaO-CaF2-P2O5-MgO-ZnO. Critical-sized calvarial defects were created in 60 male Sprague-Dawley rats. The animals were divided into 3 groups of 20 animals each. Each defect was filled with a constant weight of 0.5 g calcium phosphate glass powder mixed with saline. As controls, the defect was left empty. The rats were sacrificed 2 or 8 weeks after postsurgery, and the results were evaluated using histological as well as histomorphometrical studies. The particle size of the calcium phosphate was crucial; 400 μm particles promoted new bone formation, while 40 μm particles inhibited it because of severe inflammation.

In this study, the antibacterial effects of glass ionomer cement containing silver-zeolite were evaluated. New antibacterial glass ionomer cements with silver-zeolite were prepared as follows. Silver-zeolite (1, 3, and 5 wt%) was incorporated into the glass ionomer cement powder and then mixed with the polyacidic liquid at the ratio recommended by the manufacturer. Agar diffusion test was used to evaluation of antibacterial effect. Setting time, film thickness and compressive strength were also determined. Paired samples t-tests and ANOVA were used, and P

Objective The study assessed the cytotoxicity and immunomodulatory/anti-inflammatory effect of extract from zinc oxide–eugenol (ZOE)-based dental materials during setting using immortalized human dental pulp stem cells (IHDPSCs) and mouse bone marrow monocytes (IMBMMs), and identified the responsible extract component. Methods In accord with the ISO 10993-12, we extracted a mixture of ZOE cement and sealer after a specified time. The extract was analyzed by two types of mass spectrometry (ICP-MS and GC–MS). Cell viability was evaluated with extract and serial concentrations of ZnCl2, ZnSO4, and eugenol liquid by WST assay. The immunomodulatory/anti-inflammatory effect of a ZOE component was determined by RT-PCR to detect the downregulatory effect of inflammatory mRNA expression after lipopolysaccharide (LPS)-induced inflammation. Results Zn2+ and eugenol (2–20 ppm) were detected in the ZOE cement and sealer extracts. During the early stage of setting, significant cytotoxicity was observed in IHDPSCs and IMBMMs (p Significance ZOE was highly cytotoxic, especially during setting, to both cells due to Zn2+ while the immunomodulatory/anti-inflammatory effect of ZOE was induced by eugenol.

Magnetite nanoparticles with super-paramagnetic properties have great potential to achieve advances in fields such as hyperthermia, magnetic resonance imaging and magnetic drug targeting. In particular, magnetic particles less than 50 nm are easily incorporated into cells and generate heat under an alternating magnetic field by hysteresis loss. Various methods of preparing magnetic particles have attracted attention, such as spray pyrolysis, microwave irradiation of ferrous hydroxide, microemulsion technique and hydrothermial preparation technique. In this study, magnetite nanoparticles were synthesized with various molar ratio of Fe2+ and Fe3+ by coprecipitation using spray-guns and dropping syringe. Experiments at different molar concentrations of Fe ions were conducted, which shows the ideal molar concentration of Fe2+ to be 0.5 M for pure magnetite. Both in the spray and drop method, pure magnetite nanoparticles could be synthesized when the molar concentration of Fe2+ was 0.5 M. With increasing the molar ratio of Fe2+, the particle size of the magnetite nanoparticles was increased. The smallest size could be reduced to approximately 7 nm by the spray method. The shape of the synthesized nanoparticles was nearly spherical. The calculated highest loss power by hysteresis losses was 597 W/g, generated with a molar concentration ratio of 0.5:1 (Fe2+:Fe3+).

The purpose of this study was to investigate bioactivity of calcium phosphate coatings prepared by electrodeposition in a modified simulated body fluid (SBF). Calcium phosphates were electrodeposited on commercially pure titanium substrates in the modified SBF at 60 °C for 1 h maintaining the cathodic potentials of − 1.5 V, − 2 V, and − 2.5 V (vs. SCE). Subsequently, the calcium phosphate coatings were transformed into apatites during immersion in the SBF at 36.5 °C for 5 days. The apatites consisted of needle-shaped crystallites distributed irregularly with different grain sizes. As the coatings were electrodeposited at higher cathodic potential, the crystallite of the apatites got denser and the grain sizes of the apatites became bigger during subsequent immersion in the SBF. However, as the coatings were electrodeposited at higher cathodic potential, the coatings were transformed into apatites with lower crystallinity and the Ca/P atomic ratio of the apatites got higher than 1.67, that of stoichiometric hydroxyapatite, after subsequent immersion in the SBF. In addition, CO32− ions contained in the modified SBF were incorporated in the calcium phosphate coating during electrodeposition and had an influence on transforming the calcium phosphate into bonelike apatite during subsequent immersion in the SBF showing that CO32− incorporated in the apatites disturbed crystallization of the apatites. These results revealed that the coating electrodeposited at − 2.0 V (vs. SCE) in the modified SBF containing CO32− ions was the most bioactive showing transformation into carbonate apatite similar to bone apatite.

Tissue engineering presents an alternative approach to the repair of a damaged tissue by avoiding the need for a permanent implant made of an engineered artificial material. A suitable temporary scaffold material that exhibits adequate mechanical and biological properties is required to enable tissue regeneration by exploiting the body’s inherent repair mechanism, i.e. a regenerative allograft. Synthetic bioresorbable polymers have been attracting attention as tissue engineering scaffolds. However, a number of problems have been encountered such as inflammatory responses and lack of bioactivity. Another good candidate for a tissue engineering scaffold is the calcium phosphates because of their good biocompatibility and osteointegrative properties. Their slow biodegradation is still remains problem, especially for the filling of large bony defects. In this study, we investigated the fabrication method of a three-dimensional reticulated scaffold with interconnected pores of several hundred micrometers using calcium phosphate glass in the system of CaO-CaF2-P2O5-MgO-ZnO and a polyurethane sponge as a template. Calcium phosphate glass slurry was homogenously thick coated when the weight percentage of the calcium phosphate glass powder was 40% with 8 wt% of polyvinyl alcohol as a binder. Addition of 10 wt% dimethyl formamide as a drying control chemical additive into a slurry almost prevented the crack formation during drying. Sintering of the dried porous block at 850°C exhibited the densest microstructure as well as the entire elimination of the organic additives. Repeating the process significantly increased compressive strength of sintered porous body due to the thickening of the struts. To summarize, macroporous calcium phosphate glass can be fabricated with 500∼800 μm of pore size and a three-dimensionally interconnected open pore system. It is thought that this kind of biodegradable glass scaffold combined with osteogenic cells has potential to be studied further as a tissue-engineered bone substitute.

The formation of titanium oxide layer with micro and nanotube arrays on titanium substrate was investigated by grit-blasting and anodic oxidation treatment. Micro rough surface can be formed by grit-blasting and nanotube arrays can be formed by anodic oxidation. The morphology of the hybrid surface(micro and nanotube arrays surface) can be affected by the mechanical conditions (grit size, grit material, blasting pressure, nozzle tip of blasting machine, distance nozzle tip and specimen, blasting time) and electrochemical conditions (applied potential, electrolyte concentration and anodizing time) used. Such micro pore and nanotube arrays of titanium oxide can be useful for well-adhered bioactive surface layer on Ti implant metals for orthopedic and dental implants, as well as for photo catalysts and other sensor applications.

In preliminary ageing test, the cement using only calcium phosphate glass as power phase cracked with 1 day in simulated body fluid because of high dissolution rate of the cement. We added 30 wt% of either β-TCP or HA to 70 wt% calcium phosphate glass as powder phase to control the dissolution rate of the cement and performed in vitro ageing test in simulated body fluid by dynamic protocol as well as static protocol to confirm the possibility of controlling. Adding either β-TCP or HA to the cement increases the setting time and decreases the compressive strength. In dynamic assay, the pH of extract is maintained over 7. However, pH decreased to around 5 in static assay. Therefore, weight loss by static protocol continuously increased for 14 days, while weight loss by dynamic protocol almost saturated. In XRD patterns of ageing cements, CaO peaks appeared. CaO peak was maximized most lately in dynamic assay of the cement adding HA and within 7 days, the cement adding HA showed higher weight loss. It is indicated that CaO formed in surface of the cement hinder the dissolution of the cement. In addition, compressive strength increased when the CaO peak was maximized.

The objective of this study was to produce a macroporous hydroxyapatite(HA) scaffold with high strength by controlling the size of HA particles as well as cooling rate from the sintering temperature. Macroporous polyurethane sponge was employed as template to manufacture the macroporous HA scaffolds. Particle sizes of HA powders selected in this study were 4 µm and 7 µm. They were dispersed in distilled water with organic additives and infiltrated into polyurethane sponge. After drying and sintering at 1300oC, cooled down to room temperature slowly to prevent microcracking either 1oC/min or 3oC/min. Density, porosity and compressive strength were measured with different particle size and cooling rate. Both density and compressive strength were increased with decreasing particle size or cooling rate, while porosity was not related to.

In this study, the osteoconductive properties of novel cyanoacrylate-based filling materials for bone defect were evaluated. A new filling material was prepared by mixing Histoacryl® and acid-treated -tricalcium phosphate ( -TCP). Mixing weight ratio of acid-treated -TCP to Histoacryl® was 5:1. 12 male Spraque-Dawley rats were used in this study. The animals were divided into 4 groups. Critical-sized calvarial defects (8 mm) were created in 9 animals, and then the defects were treated with dense pellet specimen, porous cement-like specimen, and untreated defect for surgical control group. Augmentation treatments were carried out in 3 animals. Histological analysis revealed excellent ostgeoconductive properties of new filling materials. But, some of -TCP particle in the cement-like group were encapsulated by fibrous connective tissue. For the dense pellet group and augmentation treatment group, shape and stability were better maintained during the implantation time than cement like group. These results indicate that our novel -TCP/Histoacryl® composite have the potential to serve as filling materials for bone defects in the dental and plastic surgery.

A numerous techniques have been applied to fabricate three-dimensional scaffolds of high porosity and surface area. And X-ray micro computed tomography can be used studying the architecture of scaffold. In this study, we fabricated three-dimensional macroporous scaffold by polymeric sponge method using calcium phosphate glass. Calcium phosphate glass slurry was prepared by dissolving the glass powder in water polyvinyl alcohol, polyethylene glycol and dimethyl formamide. Reticulated polyurethane sponges were used as a template and were coated with the prepared slurry by infiltration technique several times. Sintering at 950oC exhibited dense microstructure as well as entire elimination of organic additives. By repeating the coating and sintering process, it was possible to decrease the pore size and be thick the strut of the structure. The unique feature of the micro computed tomography is that the three dimensions computed reconstruction can be sliced along any direction to gain accurate information on the internal geometric properties and structural parameters of scaffold. Porosity, surface area per unit volume and mean thickness of strut were evaluated through imaging and computer software of scaffold scan data.

The mixed pastes of binary calcium phosphate glass with Ca/P ratio of 0.6 and distilled water were set after about 4 hr, while never set when calcium phosphate glass with Ca/P lower than 0.5. Their compressive strength was ranged from 16.0 to 23.3 MPa. When Na2HPO4 solution was used instead of distilled water as liquid phase, the setting time became drastically much shorter. As the mole concentration of Na2HPO4 solution increased from 0.25 M to 2 M, setting time was shortened to 35 min from almost 3 hr, but compressive strength decreased from 28.8 MPa to 13.2 MPa. At constant mole concentration, as the mass ratio of a powder to liquid ratio increased, setting time was shortened and maximum compressive strength was measured when a powder/liquid ratio was 2.5. However, no crystallized phases were detected either during setting or after complete setting. The XRD , FT-IR and SEM examinations indicated that calcium phosphate glass dissolved and then glass phase precipitated again. We concluded, therefore, that Na2HPO4 just affected the kinetics of dissolution and precipitation of CPG. The mechanism of hardening has yet to be studied.

The purpose of this study was to compare the bone regenerative effect of calcium phosphate glass and glass-ceramics in the system of CaO-CaF2-P2O5-MgO-ZnO, which is already reported that promoted the bone-like tissue formation in vitro and formed new bone in Sprague-Dawley rats. We prepared calcium phosphate glass and glass-ceramics with Ca/P ratio of 0.6 using the system CaO-CaF2-P2O5-MgO-ZnO and subsequently milled to 400 µm. 4×4 mm 1-wall intrabony defects of six beagle dogs were surgically created and used in this study. 8 weeks after transplantation of the prepared calcium phosphate glass and glass-ceramics in the experimental group 1 and 2, respectively, the animals were sacrificed. No root resorption or ankylosis were observed in all groups. It can be examined that the prepared glass-ceramics were more effective in alveolar bone regeneration with statistical signigicant difference. In cementum regeneration, both the prepared glass and glass-ceramics showed significantly different effect. However, there were no statistical significant difference neither in glass nor glass-ceramics in the amounts of junctional epithelium migration and connective tissue adhesion. Further study is required to control the flowability as well as reduce the absorption rate in vivo.

The purpose of this study was to evaluate the cytotoxicity of alginate-encapsulting ferrite particles in vitro. Various ferrite particles such as Ba-ferrite, Sr-ferrite, Co-ferrite, Co/Ni-ferrite were prepared by sol-gel process. Ferrite particles were encapsulated via calcium alginate process with different alginate contents ranged from 10 to 100 wt%. Mouse-fibroblastic NCTC L-929 cells were cultured in RPMI-1640 medium with 10% fetal bovine serum. The alginate-encapsulating ferrites were extracted in 5 ml of distilled water under pH 6.5 at 121°C for 1 h in accordance with ISO 10993-12. In vitro cytotoxicity was evaluated by WST-1. The results of this study indicated that the alginate-encapsulting ferrite particles affected cell viability by increasing alginate contents. Especially, alginate-encapsulating process were enhanced cell viability of ferrites such as Sr-ferrite, Co/Ni-ferrite, and Ba-Ferrite when alginate content was 10 wt%.

This study presents the manufacture of macroporous hydroxyapatite scaffolds with a small amount of calcium phosphate glass powder as sintering additives. Hydroxyapatite slurry was prepared by suspending the hydroxyapatite and glass powder in water. Polyurethane sponge was used to produce highly macroporous scaffolds. The rheological characteristic of the slurry was measured to identify the effect of adding calcium phosphate glass powder into hydroxyapatite slurry. Sintered scaffolds could be repeatedly coated to improve mechanical properties. Scaffolds prepared by single and double replication cycle process were characterized by density, porosity and compressive strength measurements by increasing amount of the calcium phosphate glass powder to the hydroxyapatite slurry, viscosity by increased more than same amount of pure hydroxyapatite, and the capillary force was similar to pure hydroxyapatite slurry. The compressive strength of the macroporous hydroxyxapatite scaffold containing the calcium phosphate glass powder showed higher value than that of pure hydroxyapatite at single replication cycle. SEM demonstrated that the microstructure of the scaffold became denser with the introduction of the calcium phosphate glass powder. The pore struts were thicker as replication cycle was increased.

Cytotoxicity test was essential for the pre-clinical evaluation of bioceramics. Proliferation assays such as MTT, XTT and WST-1 were commonly used for measuring biocompatibility. WST-1 was more convenient than MTT because of its water-solubility and storage condition. The calcium phosphate glass and β-TCP have been used for bone substitute, and some magnetic ferrites have been used for hyperthermic treatment. L929, mouse fibroblast cell, was the representative cell-line for in vitro biocompatibility test. The extracts of test samples were prepared by ISO10993-12:2002. The biocompatibilities of the extracts were measured by MTT and WST-1 assay and their pH were measured with pH meter. The cellular survival rate of CPG was the lowest and the results of the WST-1 test showed results similar to those of the MTT test. Thus, proliferation assays using WST-1 may be conveniently and routinely applicable to pre-clinical evaluation of bioceramics.

The development of phosphate glasses for use in orthopaedic implants has attracted much interest because their chemical and physical properties make them suitable for use as bone-bonding materials. We prepared various compositions of CaO-P2O5-MO or CaO-P2O5-M2O (M: K, Li, Na, Mg, Zn) glasses to measure ion release, solubility and bioactivity. The compositions with (Ca,M)/P molar ratio 0.6 were fixed P2O5 mol% content at 45.45 mol%, and varying MO or M2O mol% at 10, 20 and 30 mol%. Ca2+ ion release properties were investigated in 0.1M potassium acetate with pH 6 at 37oC by immersing 50 mg of powder into 100 ml of acidic buffer solution. The highest and lowest extent of released Ca2+ ion was observed for composition with 10 mol% of K2O and 30 mol% of MgO, respectively. The weight loss in distilled water at 37oC was measured. Solubility increased with decreasing CaO content, but decreased with increasing MgO content. Bioactivity in the simulated body fluid at 37oC was measured.

Dental impression materials are used to register or reproduce the form and relationship of the teeth and oral tissues. They should not be torn when removing from the wet mouth after setting. Nowadays, silica is widely used as filler to overcome the low mechanical strength of the dental impression materials. The purpose of this study was to synthesize high strength glass in the system of MgO-CaO-Al2O3-SiO2 and investigate its usefulness according to ISO standard after mixing with addition silicone. Commercial products, Contrast, Examix, Express, and Perfect-F were selected as control group. When the prepared glass filler was introduced in addition silicone impression material, tear strength was drastically increased significantly than that of the control group, keeping the consistency. All experimental groups showed higher tear stength than that of control groups. As the amount of filler content increases, tear strength was increased. Strain in compression, recovery from deformation, and linear dimensional change were satisfied the ISO standard either all the experimental or control groups. Therefore, calcium-substituted magnesium aluminosilicate glass in the system of 12.5MgO-17.5CaO-20Al2O3-50SiO2 is expected the useful filler in the light body of addition silicone impression materials.

The purpose of this study was to evaluate the cell affinity of calcium phosphate glass scaffold in the system of CaO-CaF2-P2O5-MgO-ZnO, which is already reported that promoted the bone-like tissue formation in vitro and formed new bone in Sprague-Dawley rats. We prepared calcium phosphate glass saffolds with three-dimensionally interconnected pores of 200~500 µm. Commercial HA scaffold was employed as a control in this study. Bone marrow cells were collected from the healthy human donors and cultured within the prepared scaffolds. After 2, 4, 6, and 8 weeks, hMSCs/scaffold were fixed and stained with hematoxylin and eosin. hMSCs were continuously proliferated both in the experimental and control groups at every incubation period. The number of cells was higher in the experimental group than that of the control group, however, there was no significant difference (p>0.05). Extracellular matrices could be observed at the 2nd and 4th days in the experimental and control groups, respectively. The extracellular matrices were more abundant in the experimental group at all periods. The prepared calcium phosphate glass scaffolds are expected effective in bone tissue engineering.

The coatings formed on the H2O2-treated titanium substrate by electrodeposition were used in order to evaluate the difference of transformations in the simulated body fluid (SBF) and the culture medium with MG63 cells. A porous hydroxyapatite (HA) coating with relatively low crystallinity and large crystallites was formed on the H2O2-treated titanium substrate by electrodeposition. HA coating transformed for 5 days in the SBF consisted of densely-packed rod-shaped crystallites with various differentiated grains. Octacalcium phosphate (OCP) and HA coating transformed for 5 days in the culture medium consisted of both flake-shaped and rod-shaped crystallites with indistinct grains. MG-63 cells were well attached and proliferated during the transformation into this flaked-shaped OCP. This difference between transformations of the HA coatings in the acellular SBF and in the culture medium with MG63 cells is due to different ion composition in each solution and proteins in culture medium.

Alkali oxides were added to glass frit in order to lower the firing temperature of dental porcelain, and the effects of Li2O and B2O3 on the thermal properties and chemical solubility of low-fusing dental porcelain were investigated. The glass transition temperature(Tg) and softening temperature(Ts) of glass frits were decreased remarkably by adding Li2O, but the coefficient of thermal expansion(CTE) was increased with Li2O. In the case of adding B2O3, the thermal properties were unchanged. Tg of B0L4, B2L4 and B4L4 specimens were lower than 500°C and Ts were lower than 550°C. The chemical solubility of prepared low-fusing dental porcelain with these glass frits were 37.3, 43.9, and 49.2µg·cm-2 respectively. The chemical solubility was increased by adding Li2O and B2O3, but all the results were below 100µg·cm-2 and satisfactory to ISO Standards. Further, the chemical solubility of the commercial low-fusing dental porcelains were 52.6µg·cm-2 for Ceramco Finesse(Clear), 70.8µg·cm-2 for Duceram-LFC(TC) and that of conventional dental porcelain, CeraMax(T-C), was 34.8µg·cm-2.

Ceramic ferrites can be used to cancer-treatment. Heating of certain organs or tissue up to temperature between 42oC and 45oC preferentially for cancer therapy is called hyperthermia. We synthesized ferrites with various compositions in the system Co1-xNixFe2O4 as hyperthermic thermoseed in cancer-treatment and evaluated their effects on the necrosis of cancer cells under alternating magnetic field in vivo as well as in vitro. When a CoFe2O4 was placed into 0.2 ml distilled water, the greatest temperature change in this study, Δ T=29.3oC, was observed. More than half of the carcinoma cells were dead after exposure to alternating magnetic field using CoFe2O4, while normal cells were survived more than 60%. The injection of this ferrite particles into the tumor bearing mice was able to suppress the number and volume of tumors. CoFe2O4 is expected the useful hyperthermic thermoseed in cancer-treatment because it exhibited the greatest necrosis of carcinoma cells in vitro and in vivo.

In tissue engineering, a scaffold helps determine 3-dimensional morphology, increases cell survival, provides initial mechanical stability, supports tissue ingrowth, aids in the formation of tissue structure. Chitosan is the partially deacetylated form of chitin that can be extracted from crustacean. It degrades in the body to non-harmful and non-toxic compounds and has been used in various fields such as nutrition, metal recovery and biomaterials. Hydroxyapatite, a major inorganic component of bone, has been used extensively for biomedical implant applications and bone regeneration due to its bioactive, biodegradable and osteoconductive properties. The application, however, of hydroxyapatite is limited due to own brittleness. Since the natural bone is a composite mainly consisted of organic collagen and inorganic hydroxyapatite, many efforts have been made to modify hydroxyapatite by polymers. In this study, organic/inorganic hybrids were fabricated solid-liquid phase separation and a subsequent freeze-drying process. The microstructure, mechanical properties, and bioactivity of the scaffolds with various contents of hydroxyapatite were studied. The structure of the scaffolds prepared was macroporous and interconnected. The compressive mechanical properties such as compressive modulus and yield strength were improved according to the increase of hydroxyapatite contents mixed with chitosan. After 7 days of sample immersion in a simulated body fluid, for scaffolds containing hydroxyapatite, numerous bonelike apatites were formed on the surfaces of the pore walls. This study suggests that desirable pore structure, mechanical properties, and bioactivity of the hybrid scaffolds might be achieved through controlling the ratio of hydroxyapatite and chitosan.

We tried to prepare a new filling material for bone defects using β-Tricalcium phosphate (β-TCP) particles and Histoacryl®. The aim of this study was to evaluate physical and bioactive properties of cyanoacrylate-based filling materials for bone defects in the dental field. The shear bond strength values of the Histoacryl® and β-TCP/ Histoacryl® compounds stored in double-distilled water decreased with the increase of the amount of added β-TCP. The temperature change of the β-TCP/ Histoacryl® compounds during polymerization decreased compared to that of the Histoacryl®. The cytotoxicity of the filling materials decreased when the amount of added β-TCP was increased. In the evaluation of bioactivity, hydroxyapatite (HA) was precipitated on the surface and inner space of the porous filling material 4 weeks after immersion in SBF. This precipitation of HA on the surface of the filling material was also confirmed in the XRD result. These results indicate that our novel β-TCP/Histoacryl® compounds have the potential to serve as filling materials for bone defects in the dental field.

M-type hexagonal ferrite, MFe12O19 (M = Ba, Sr, etc.) has been intensively investigated as a material for permanent magnets, high-density recording media, and microwave devices [1]. The sol-gel technique has emerged in recent years as a versatile method for synthesizing barium and strontium ferrite. The sol-gel technique offers the following advantages: the temperature needed for the crystallization process is lower, the particles produced are ultrafine, and they have a narrow size distribution [1]. Spray pyrolysis is a valuable technique for forming a non-agglomerated complex mixed-metal oxide powders with high purity, controlled stoichiometry and crystallinity, and a relatively narrow particle-size distribution [2]. Therefore, the solgel method prior to spray pyrolysis was used to prepare the samples for obtaining powders from a sol in much shorter periods compared to those needed using the traditional evaporation-drying procedure [3]. Appropriate portions of Ba(NO3)2, (CH3CO2)2Sr, and Fe(NO3)2·9H2O were dissolved in ethylene glycol, methyl alcohol and distilled water in the stoichiometric ratio, namely (Ba, Sr)/Fe = 1/10. The solution was refluxed at 80 ◦C for 12 hrs. The spray pyrolysis equipment used in this study consisted mainly of an ultrasonic nebulizer (H556, LG Electronics, Korea), a furnace, a glass fiber filter (GF/F, Whatman, England) and a rotary pump [4]. The aerosol droplets were produced by ultrasonic frequency (1.67 MHz) and were nebulized at flow rates of 1–5 /min. The droplets were then passed through a low temperature first heating zone (300 ◦C) where the solvent was evaporated. The resulting dried particles were subsequently passed through a second heating zone (400–1000 ◦C) where the particles decomposed [5]. The powders were finally recovered by a glass fiber filter of 0.7 μm of pore size and were dried at 100 ◦C for 24 hrs. In order to study the changes in a crystalline