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Peri-implantitis is an inflammatory disease similar to periodontitis, caused by biofilms formed on the surface of dental implants. This inflammation can spread to bone tissues and result in bone loss. Therefore, it is essential to inhibit the formation of biofilms on the surface of dental implants. Thus, this study examined the inhibition of biofilm formation by treating TiO2 nanotubes with heat and plasma. Commercially pure titanium specimens were anodized to form TiO2 nanotubes. Heat treatment was performed at 400 and 600 °C, and atmospheric pressure plasma was applied using a plasma generator (PGS-200, Expantech, Suwon, Republic of Korea). Contact angles, surface roughness, surface structure, crystal structure, and chemical compositions were measured to analyze the surface properties of the specimens. The inhibition of biofilm formation was assessed using two methods. The results of this study showed that the heat treatment of TiO2 nanotubes at 400 °C inhibited the adhesion of Streptococcus mutans (S. mutans), associated with initial biofilm formation, and that heat treatment of TiO2 nanotubes at 600 °C inhibited the adhesion of Porphyromonas gingivalis (P. gingivalis), which causes peri-implantitis. Applying plasma to the TiO2 nanotubes heat-treated at 600 °C inhibited the adhesion of S. mutans and P. gingivalis.

In this study, the wear behavior of glazed zirconia was investigated to the antagonist with human enamel after simulated mastication. Twenty Y-TZP specimens were divided into 4 groups: untreated zirconia (Z), glazed zirconia with IPS e.max Ceram (GZE), glazed zirconia with VITA AKZENT® Plus (GZV), and glazed zirconia with glass (GZG). Glazing glass was mainly composed of SiO2, B2O3, Al2O3, Na2O and K2O (nearly 91 wt%). The surface roughness of the specimens was evaluated using roughness profiler. The maxillary premolar teeth were selected as the antagonist. The wear of human enamel against human enamel was used as a control. Five-disc specimens per group were subjected to chewing stimulation CS-4 (SD Mechatronic GmbH, Germany) for 240,000 cycles against human enamel. The wear loss of antagonistic teeth was calculated using a three-dimensional profiling system and the volume loss of the tooth was scanned using a 3D scanner. 3D data obtained before and after testing were overlapped using 3D software (Dentacian Software, EZplant, Korea). The wear loss of glazed zirconia GZE, GZV and GZG groups showed significantly lower than that of human enamel. Whereas, the zirconia (Z) group exhibits significantly lower volume loss than glazed zirconia and enamel. These results show that the wear of the glazing glass is comparable to other commercial glazing materials. Glazing materials are both more susceptible to wear the antagonist relative to zirconia.

Periimplantitis is an inflammation similar to periodontitis, and is caused by biofilms formed on the surface of dental implants. Application of plasma on biomaterials has been reported to decrease the initial adhesion of microorganism by causing chemical changes without changing the surface morphology. The purpose of this study is to evaluate the effect of inhibition of biofilm formation on the elapsed time after plasma treatment. Non thermal plasma generator (PGS-200 Plasma generator, Expantech Co., Korea) was applied to the specimens. The elapsed time in the atmosphere was set to 5 immediately after treatment, after 30 minutes of treatment, after 60 minutes of treatment, after 90 minutes of treatment. Surface property change with the elapsed time in the atmosphere after plasma treatment were confirmed by X-ray photoelectron spectroscopy and contact angle. Inhibition of biofilm formation was evaluated by the fluorescent nucleic acid staining. It was confirmed that the chemical composition and bonding state of the surface changes as the elapsed time in the atmosphere increases after plasma treatment. The adhesion of Porphyromonas gingivalis was the lowest immediately after plasma treatment, and increased again with increasing elapsed time in the atmosphere after plasma treatment. As a result of this study, it was confirmed that elapsed time in the atmosphere is a very important factor for inhibition of biofilm formation.

45S5 bioactive glass (45S5) scaffolds were fabricated using a novel additive-manufacturing (AM) technology. A ceramic injection printer (CIP) was designed by combining injection molding and fused deposition modeling, for the fabrication of three-dimensional constructs of ceramic materials. A high fraction (50 vol%) of 45S5 powder was mixed with the thermoplastic polymer. The synthesized 45S5 composites were subjected to Brunauer–Emmett–Teller (BET) analysis, X-ray diffraction (XRD) analysis, and field-emission scanning electron microscopy (FE-SEM). The BET results of prepared 45S5 powder were confirmed to have a mean pore diameter of 11.402 nm, and specific surface area is 0.966 m2/g. The prepared 45S5/thermoplastic composite powder was subjected to Thermogravimetric/Differential thermal analysis (TG/DTA). The debinding process of polymer occurred at 192.5, 360.8, and 393 °C. The elastic modulus and ultimate stress of these scaffolds were measured to be 312.49±87.36 MPa and 21.83±6.67 MPa, respectively. The XRD results revealed the presence of Na6Ca3Si6O18 phases. The presence of Si, Ca, P, and Na was confirmed via energy-dispersive X-ray spectroscopy (EDS). The printed scaffold exhibited amorphous calcium phosphate (ACP) expression after immersion in simulated body fluid (SBF) and also it was observed that the intensity of the crystalline phase of 45S5 was decreased, as the immersion time increases. Bioactive glass composites with the high volume fraction can be able to construct 3D complex porous scaffolds using CIP.

The optical and physical properties of 45S5 bioactive glass suspensions for bone tissue engineering applications were studied by (1) varying the volume fraction of 45S5 in the suspension, and (2) assessing the effects of sintering on the mechanical and morphological features of the glass. The 45S5 specimens were manufactured using stereolithography. Five types of binders with different ratios of photocurable and acrylate resins were fabricated. 45S5 bioactive glass suspensions were prepared by adding 45S5 glass powder to the binder with the highest reactivity and cure depth. The prepared suspensions were divided into five groups with 45S5 volume fractions varying in the range of 32–40 vol% (denoted as BG32–BG40, respectively). The cure depth, measured after passing a laser with a wavelength range of 390–420 nm through the suspension once, was found to decrease with increasing volume fraction of 45S5. Moreover, as the 45S5 volume fraction increased, the strength of the sample reached a maximum of 37.9 ± 5 MPa at 40 vol% (BG40). More importantly, the viscosity of the suspensions prepared with various glass fractions was found to gradually increase with increasing volume fraction. The Fourier-transform infrared spectra of the non-sintered and sintered green bodies showed three main peaks (at 1040, 920, and 445 cm−1) corresponding to the Si–O–Si bond vibrations of 45S5. Clear signals corresponding to C–H stretching and C=C bonds were observed before sintering; however, these peaks disappeared after sintering. Optical analysis showed no residual effects of the binder after sintering. These results demonstrate that the suspension with 40 vol% 45S5 (BG40) can be successfully employed in the fabrication of scaffolds for bone regeneration and tissue engineering applications in the near future.

The optical properties of zirconia photopolymer suspension for DLP (Digital Light Processing) were evaluated. The light source and intensity were set to 395 nm and 30 mW/cm². Experimental groups were divided into 48, 50, 52, 54, 56 and 58 vol% according to the zirconia volume fraction. The cure depth of all groups was at least 47.35 um when cured for 1 sec, which was higher than layer parameter values of the 3D printer. The geometrical overgrowth showed 28.55% at 48 vol% and 36.94% at 58 vol%. As the volume fraction of zirconia increased, the geometrical overgrowth increased and the cure depth reduced.

Periimplantitis is an inflammation similar to periodontitis, and is caused by biofilms formed on the surface of dental implants. Application of plasma on biomaterials has been reported to decrease the initial adhesion of microorganism by causing chemical changes without changing the surface morphology. The purpose of this study is to evaluate the effect of inhibition of biofilm formation on the elapsed time after plasma treatment. Non thermal plasma generator (PGS-200 Plasma generator, Expantech Co., Korea) was applied to the specimens. The elapsed time in the atmosphere was set to 5 immediately after treatment, after 30 minutes of treatment, after 60 minutes of treatment, after 90 minutes of treatment. Surface property change with the elapsed time in the atmosphere after plasma treatment were confirmed by X-ray photoelectron spectroscopy and contact angle. Inhibition of biofilm formation was evaluated by the fluorescent nucleic acid staining. It was confirmed that the chemical composition and bonding state of the surface changes as the elapsed time in the atmosphere increases after plasma treatment. The adhesion of

In the current study, the biocompatibility and mechanical characteristics of glass-infiltrated zirconia were improved via a simple composite coating made of Zn-doped hydroxyapatite (ZnHA) ceramic and a silicate-based glass. During thermal treatment, significant reaction and crystallisation occurred and some of the ZnHA was transformed into β-tricalcium phosphate, calcium oxide phosphate, and calcium zirconium oxide. Moreover, the glass crystallised into a sodium calcium aluminium silicate phase. The mechanical properties were investigated and the results indicated that the amount of glass in the composite and in the glass-infiltrated zirconia layer strongly affected the flexural strength and adhesion of the coating layer. The composite coatings on the glass-infiltrated zirconia displayed better mechanical properties than the pure ZnHA coating due to the newly formed crystalline phases. Murine pre-osteoblastic (MC3T3-E1) cells adhered to and spread well on the composite coating surfaces. The cell viability results revealed that the glass/ZnHA composites demonstrated a superior bioactivity of osteoblast cells compared to uncoated zirconia. These results show that the glass/ZnHA composites on the glass-infiltrated zirconia structure are suitable for use as hard tissue implant coatings due to their morphological and mechanical stability and enhanced bioactivity to pre-osteoblastic cells.

This study evaluated the effect of acid etching on surface characteristics, flexural strength and osteoblast cell response of glass-infiltrated zirconia. Zirconia specimens were divided into six groups: untreated zirconia (Z); glass-infiltrated zirconia (ZG); glass-infiltrated and sandblasted zirconia (ZGS); glass-infiltrated, sandblasted and 5 min acid-etched zirconia (ZGS-E5); glassinfiltrated, sandblasted and 15 min acid-etched zirconia (ZGS-E15); glass-infiltrated, sandblasted and 25 min acid-etched zirconia (ZGS-E25). Surface roughness, biaxial flexural strength and MC3T3-E1 cell proliferation were evaluated. When increasing etching time, surface roughness significantly increased while flexural strength decreased. Cell proliferation rate at day 3 on group ZGS-E15 and ZGS-E25 was significantly higher than that of other groups. Surface roughness and flexural strength of glass-infiltrated zirconia can be controlled by adjusting etching time. Rough surface made by acid etching following glass infiltration significantly enhanced osteoblast cell response. Glass infiltration improved strength of zirconia but severe acid etching slightly reduced strength of zirconia.

In this study, we have analysed the effects of a silane coupling agent on the volume fraction of zirconia for digital light processing (DLP)-based additive manufacturing processes. Zirconia suspension was prepared by the incorporation of silane-modified zirconia particles (experimental group) or untreated zirconia particles (control group). Furthermore, the control and experimental group were subdivided into three groups based on the volume fraction (52, 54, and 56 vol%) of zirconia particles. The disk-shaped zirconia samples were 3D (three-dimensional) printed using the DLP technique and their physical and mechanical properties were evaluated. The addition of a silane coupling agent to the zirconia samples was found to have influence of about 6% on the hardness and biaxial flexural strength. Moreover, the decrease in minute air gaps inside the zirconia layers significantly increased the material density (visualized from the microstructure analysis). Thus, from this study, it was established that the silane-modified zirconia particles had a positive effect on the physical properties of the zirconia parts.

The purpose of this study was to evaluate the fitness of zirconia cores according to the amount and treated surface of glass infiltration. A maxillary right central incisor customized abutment was milled to have a 6° slope and a 1 mm deep chamfer margin and was manufactured in an intaglio mold using silicone impression material. Fifty-six stone dies were produced by injecting high strength dental stone into a mold and then zirconia cores were milled with CAD/CAM systems. The control group (Control) used non glass-infiltrated zirconia, and the experiment group was divided by one with the glass and distilled water ratio of 1:300 and the other with the ratio of 1:100. Each group was divided into subgroups by glasstreated surface: external surface infiltration, internal surface infiltration, and both surface infiltration. The zirconia cores sintered after glass infiltration were attached to the stone dies and then cut. Afterwards, the absolute marginal discrepancies and internal gaps of the buccal and lingual sides were measured. The buccal absolute marginal discrepancies and lingual internal gaps were influenced by the glass infiltration amount (p0.05); while fitness of zirconia core were not affected by the glasstreated surface (p0.05). As a result of the above experiments, the glass-infiltrated zirconia cores showed a clinically acceptable fitness, which is within 120 μm. This means that glass infiltration can be clinically used.

Porphyromonas gingivalis (P. gingivalis) is one of main bacteria that adheres to the surface of dental implants and causes peri-implantitis. The purpose of this study was to observe the surface characteristics of titanium processed with either titanium nitride (TiN) sputter coating or plasma nitriding and to evaluate the subsequent adhesion of P. gingivalis. Specimens were divided into three groups: commercially pure (CP) titanium (control group), TiN sputter–coated titanium (group S), and plasma-nitrided titanium (group P). Surface characteristics such as roughness, morphology, and the formation of a thin TiN film or a nitriding layer were assessed. Adhesion of P. gingivalis in the three groups was determined by means of the crystal violet staining assay, and results were compared with one-way ANOVA, with post hoc comparison using Tukey’s test (α = 0.05). Surface roughness values for the control group, group S, and group P were 0.08±0.02 μm, 0.19±0.04 μm, and 0.13±0.02 μm, respectively. In group S, the TiN layer was 1.36±0.1 μm thick, and nitrogen was detected on the surface of the specimens in group P, confirming formation of a nitrided layer. The level of adhesion in group P was significantly higher than that in the control group and in group S (p < 0.05), but there was no significant difference between the control group and group S. Within the limitations of this study, TiN sputter coating did not affect adhesion of P. gingivalis on the titanium surface, whereas adhesion was increased on the plasma-nitrided titanium surface.

PURPOSE The purpose of this study was to evaluate the influence of acid etching treatment on surface characteristics and biological response of glass-infiltrated zirconia. MATERIALS AND METHODS A hundred zirconia specimens were divided into four groups depending on surface treatments: untreated zirconia (group Z); acid-etched zirconia (group ZE); glass-infiltrated zirconia (group ZG); and glass-infiltrated and acid-etched zirconia (group ZGE). Surface roughness, surface topography, surface morphology, and Vickers hardness of specimens were evaluated. For biological response test, MC3T3-E1 cell attachment and proliferation on surface of the specimens were examined. The data were statistically analyzed using one-way ANOVA and Tukey's HSD test at a significance level of 0.05. RESULTS Group ZGE showed the highest surface roughness (Ra = 1.54 µm) compared with other groups (P < .05). Meanwhile, the hardness of group Z was significantly higher than those of other groups (P < .05). Cell attachment and cell proliferation were significantly higher in group ZGE (P < .05). CONCLUSION We concluded that effective surface roughness on zirconia could be made by acid etching treatment after glass infiltration. This surface showed significantly enhanced osteoblast cell response.

This study was to investigate the various glass thicknesses on the shear bond strength between zirconia and veneering porcelain. The zirconia specimens were classified into 5 groups (n = 12). For the control group, the Y-TZP disk was sintered (G0). For the test group, the presintered zirconia disks were spin coated with different W/P ratio glass compositions. The glass thickness on the zirconia was 1 μm (G1), 4 μm (G4), 10 μm (G10), and 40 μm (G40), respectively. All specimens were build-up veneering porcelain and fired. The shear bond strength (SBS) was tested in a universal testing machine (crosshead speed = 0.5 mm/min). As the thickness of the glass decreased, the shear bond strength increased. The G1 group showed significantly higher than the control group (G0) (P < 0.05). The results suggest that the thickness of glass coating on the zirconia structure needs to be made thin for better bonding strength with veneering porcelain.

The purpose of this study was to examine the surface characteristics of bioactive glass-infiltrated zirconia specimens that underwent different hydrofluoric acid (HF) etching conditions. Specimens were classified into the following six groups: Zirconia, Zirliner, Porcelain, Bioactive glass A1, Bioactive glass A2, and Bioactive glass A3. Zirliner and porcelain were applied to fully sintered zirconia followed by heat treatment. Bioactive glass was infiltrated into presintered zirconia using a spin coating method followed by complete sintering. All the specimens were acid-etched with 10% or 20% HF, and surface roughness was measured using a profiler. The surface roughness of the zirconia group was not affected by the etching time or the concentration of the acid. The roughness of the three bioactive glass groups (A1, A2, and A3) was slightly increased up until 10 minutes of etching. After 1 hour of etching, the roughness was considerably increased. The infiltrated bioactive glass and acid etching did not affect the adhesion and proliferation of osteoblasts. This study confirmed that surface roughness was affected by the infiltration material, etching time, and acid concentration. For implant surfaces, it is expected that the use of etched bioactive glass-infiltrated zirconia with micro-topographies will be similar to that of machined or sand-blasted/acid-etched (SLA) titanium.

This study was to examine the effects of ferric oxide contents, which is one of the components of a newly developed glass, on the color and mechanical strengths of zirconia surfaces after glass infiltration. The composition of bioactive glass contained: SiO2–Al2O3–Na2O–MgO–BaO–CaO–Nb2O5–TiO2–Fe2O3. 84 presintered zirconia discs (diameter 15 mm, height 1.2 mm) were prepared. The experimental groups were divided into 6 groups by Fe2O3 contents of 0, 1, 1.5, 2.0, 2.5 and 2.9 wt%. Non-glass infiltrated zirconia was used as a control. Bioactive glass was coated on the presintered zirconia disc by a spin coating and infiltrated into zirconia by complete sintering at 1450°C for 2 hr. The color of the specimens was measured using a digital spectrophotometer and biaxial flexural strength and fracture toughness was compared. The colors of glass infiltrated zirconia were from yellow to yellowish orange according to ferric oxides contents and those were within the range of natural teeth colors. The mechanical properties of glass infiltrated zirconia were not inferior to those of zirconia. Glass infiltration with ferric oxide into zirconia can improve the color and mechanical properties of zirconia and be applicable for dental purpose.

of calcium (Ca) on the surface characteristics and physical properties of magnesium-calcium alloys after anodization. A novel binary alloy Mg-xCa (in which x = 0:5, 1, or 5 wt.%) was cast by combining magnesium (99.9%) and calcium (99.9%) in an argon gas (99.99%) atmosphere. A magnesium alloy rod having a diameter of 15 mm was cut into discs, each 2 mm thick. The specimens were subjected to anodic oxidation at 120 V for 15 minutes at room temperature in an electrolyte solution consisting of calcium gluconate, sodium hexametaphosphate, and sodium hydroxide. Surface and cross-sectional morphological changes were observed using scanning electron microscopy, and the microstructures and phases were detected by means of X-ray diraction. Hardness and surface roughness were assessed by means of a Vickers hardness tester and a surface roughness meter, respectively. The results show that the physical properties of these magnesiumcalcium alloys have been improved, because it was possible to control the dissolution rate according to the amount of calcium added. DOI: 10.12693/APhysPolA.129.736 PACS/topics: 87.85.jj, 87.85.jc

In this study, we examined the effect of β-tricalcium phosphate (β-TCP) coating on alkali-treated CP Grade II titanium surface via RF magnetron sputtering on osteoblast like cell (MC3T3-E1) viability and bone formation in rat tibia. The specimens were divided into three groups; commercially pure titanium (control group), alkali-treated titanium with nanofiber structure (NF group) and β-TCP coating on alkali-treated titanium with nanofiber structure (TNF group). The surface characteristics of specimens were observed under a field emission scanning electron microscope (FE-SEM), and contact angle was measured. The cell viability was assessed in vitro after 1 day, 3 days and 7 days. Implants of 2.0 mm diameter and 5.0 mm length were inserted into the tibia of rats. After 4 wks, the histomorphometric analysis was performed. Group NF and group TNF showed improved hydrophilicity of Ti. Group TNF showed significantly higher cell viability (P < 0.05) after 7 days. The bone to implant contact (BIC) ratio of the control group, NF group, and TNF group were 32.3%, 35.5%, and 63.9%, respectively. The study results suggested that β-TCP coated alkali-treated titanium surface via RF magnetron sputtering might be effective in implant dentistry due to enhanced hydrophilicity, improved cell response, and better osseointegration.

The aim of this study was to determine the effect of hydroxyapatite (HA) coating on titanium dioxide (TiO2) nanotube by sol-gel process on viability of osteoblast like cell (MC3T3-E1) and bone formation in rat tibia. Specimens were divided into three groups including commercially pure titanium (control group), TiO2 nanotubes (group N), and HA coated TiO2 nanotubes (group HN). Surface characteristics were determined using field emission scanning electron microscope (FE-SEM; S-4700, Hitachi, Japan) and contact angles were measured. Cell viability was investigated in vitro after 1 day, 3 days, and 7 days of incubation. Implants (2.0 mm in diameter and 5.0 mm in length) were inserted into the tibia of rats. After 4 weeks, histomorphometric analysis was performed. Both N and HN groups showed enhanced hydrophilicity compared to control group. After 7 days of implantation, group HN showed higher cell viability with marginal significance (0.05 < P < 0.1). Bone to implant contact (BIC) ratio in the control group, group N, and group HN were 32.5%, 33.1%, and 43.8%, respectively. Results of this study showed that HA coated TiO2 nanotube using sol-gel process could be used to enhance hydrophilicity and improve osseointegration of dental implant surface.

This study evaluated the shear bond strength of zirconia to titanium implant components using silica-based glasses and compared the strength with that of implant components bonded using a commercial resin cement. Forty cylindrical zirconia specimens and forty titanium disks (Grade IV) were divided equally into four groups, depending on the adhesive used: three different types of glasses (group G, group GI, group GIB) and a self-adhesive resin cement (group U200), which was used as a control. The shear bond strength was evaluated using a universal testing machine and failure mode was examined by optical microscope. Data was analyzed using One-way ANOVA with p-value

The aim of this study was to evaluate the antibacterial activity against Streptococcus mutans and fibroblast viability of zirconia coated with glass ceramic powder containing Ag and F nanoparticles. Specimens were divided into eight groups depending on the glass ceramic powders: 5, 10, 15, 20 wt% of NaF and Ag, respectively. Adhesion of Streptococcus mutans on glass-coated zirconia surface was evaluated by antimicrobial test. Fibroblast viability was examined by WST-8 assay. In result, the bacterial activity was reduced by 11.8%, 15.4% in Ag 10 wt% and 20 wt% groups. When 5~15 wt% of NaF was added, bacterial counts decreased to 4.2~65.4%, and when 20 wt% of NaF was added, the number of bacteria increased by 29.4%. Regardless of Ag and NaF content, all zirconia specimens showed cell viability above 70%. Within the limitations of this study, zirconia coated with glass ceramics powder containing Ag and NaF was found to reduce the adhesion of Streptococcus mutans but had no influence on osteoblast activation.

This study investigated the mechanical properties and initial cell response of bioactive glass infiltrated zirconia before and after sandblasting. One hundred zirconia specimens were divided into the following four groups: untreated zirconia (ZR), sandblasted zirconia (ZS), glass infiltrated zirconia (ZG), and sandblasted glass infiltrated zirconia (ZGS). Surface roughness, biaxial flexural strength, hardness and osteoblast cells proliferation were evaluated. ZGS group showed a slight decrease in hardness. However it has improvement in flexural strength (686.2 MPa). After sandblasting, the ZGS group had the highest surface roughness (R a = 1.24 μm) with enhanced osteoblast cells response. Our results indicated that sandblasting method can improve the mechanical properties of bioactive glass infiltrated zirconia with better osteoblast cell response. This new surface is promising for zirconia dental implant application in the future.

The purpose of this study was to examine the surface characteristics of bioactive glass-infiltrated zirconia specimens that underwent different hydrofluoric acid (HF) etching conditions. Specimens were classified into the following six groups: Zirconia, Zirliner, Porcelain, Bioactive glass A1, Bioactive glass A2, and Bioactive glass A3. Zirliner and porcelain were applied to fully sintered zirconia followed by heat treatment. Bioactive glass was infiltrated into presintered zirconia using a spin coating method followed by complete sintering. All the specimens were acid-etched with 10% or 20% HF, and surface roughness was measured using a profiler. The surface roughness of the zirconia group was not affected by the etching time or the concentration of the acid. The roughness of the three bioactive glass groups (A1, A2, and A3) was slightly increased up until 10 minutes of etching. After 1 hour of etching, the roughness was considerably increased. The infiltrated bioactive glass and acid etching did not affect the adhesion and proliferation of osteoblasts. This study confirmed that surface roughness was affected by the infiltration material, etching time, and acid concentration. For implant surfaces, it is expected that the use of etched bioactive glass-infiltrated zirconia with micro-topographies will be similar to that of machined or sand-blasted/acid-etched (SLA) titanium.

The aim of this study was to evaluate the antibacterial activity against Porphyromonas gingivalis and osteoblast viability of heat and plasma treatment of TiO2 nanotubes. Specimens were divided into four groups: the Ti (polished titanium), Nano (TiO2 nanotube), NH 300 (heat treated at 300 °C on TiO2 nanotube) and NH 400 (heat treated at 400 °C on TiO2 nanotube) groups. Antibacterial activity and osteoblast viability were evaluated in the four groups according to plasma treatment. Surface adhesion of Porphyromonas gingivalis was evaluated by crystal violet assay. Osteoblast viability was examined by XTT assay. Adhesion of Porphyromonas gingivalis was significantly decreased in the Ti group, Nano group and NH 300 group after plasma treatment (P < 0.05). Osteoblast viability was increased in the NH 400 group in comparison to the Ti group before plasma treatment (P < 0.05). Within the limitations of this study, plasma treatment was found to reduce the adhesion of P. gingivalis but had no influence on osteoblast activation.

Hydroxyapatite (HA) coating on titanium dioxide (TiO2) nanotubular surface has been developed to complement the defects of both TiO2 and HA. A sol-gel processing technique was used to coat HA on TiO2 nanotubular surface. All the titanium discs were blasted with resorbable blast media (RBM). RBM-blasted Ti surface, anodized Ti surface, and sol-gel HA coating on the anodized Ti surface were prepared. The characteristics of samples were observed using scanning electron microscopy and X-ray photoemission spectroscopy. Biologic responses were evaluated with human osteosarcoma MG63 cells in vitro. The top of the TiO2 nanotubes was not completely covered by HA particles when the coating time was less than 60 sec. It was demonstrated the sol-gel derived HA film was well-crystallized and this enhanced biologic responses in early stage cell response.

In this study, we examined the effect of β-tricalcium phosphate (β-TCP) coating on alkali-treated CP Grade II titanium surface via RF magnetron sputtering on osteoblast like cell (MC3T3-E1) viability and bone formation in rat tibia. The specimens were divided into three groups; commercially pure titanium (control group), alkali-treated titanium with nanofiber structure (NF group) and β-TCP coating on alkali-treated titanium with nanofiber structure (TNF group). The surface characteristics of specimens were observed under a field emission scanning electron microscope (FE-SEM), and contact angle was measured. The cell viability was assessed in vitro after 1 day, 3 days and 7 days. Implants of 2.0 mm diameter and 5.0 mm length were inserted into the tibia of rats. After 4 wks, the histomorphometric analysis was performed. Group NF and group TNF showed improved hydrophilicity of Ti. Group TNF showed significantly higher cell viability (P0.05) after 7 days. The bone to implant contact (BIC) ratio of the control group, NF group, and TNF group were 32.3%, 35.5%, and 63.9%, respectively. The study results suggested that β-TCP coated alkali-treated titanium surface via RF magnetron sputtering might be effective in implant dentistry due to enhanced hydrophilicity, improved cell response, and better osseointegration.

The aim of this study was to determine the effect of hydroxyapatite (HA) coating on titanium dioxide (TiO2) nanotube by sol-gel process on viability of osteoblast like cell (MC3T3-E1) and bone formation in rat tibia. Specimens were divided into three groups including commercially pure titanium (control group), TiO2 nanotubes (group N), and HA coated TiO2 nanotubes (group HN). Surface characteristics were determined using field emission scanning electron microscope (FE-SEM; S-4700, Hitachi, Japan) and contact angles were measured. Cell viability was investigated in vitro after 1 day, 3 days, and 7 days of incubation. Implants (2.0 mm in diameter and 5.0 mm in length) were inserted into the tibia of rats. After 4 weeks, histomorphometric analysis was performed. Both N and HN groups showed enhanced hydrophilicity compared to control group. After 7 days of implantation, group HN showed higher cell viability with marginal significance (0.05P0.1). Bone to implant contact (BIC) ratio in the control group, group N, and group HN were 32.5%, 33.1%, and 43.8%, respectively. Results of this study showed that HA coated TiO2 nanotube using sol-gel process could be used to enhance hydrophilicity and improve osseointegration of dental implant surface.

In this study, the effect of transition metal dopants, originally added as colouring agents, on the mechanical properties and biocompatibility of sintered zirconia was investigated. This study confirmed that transition metal dopants could have a slight detrimental effect on the mechanical properties of zirconia. The addition of metal dopants did not affect the adhesion and proliferation of gingival fibroblasts.

Specimens of Ti-10Ta-10Nb have become hot forging after being heated to the state of α + β or â-phase. Various temperatures (650, 700, 750, 800, 850°C) and strain rates (0.001, 0.01, 0.1, 1, 10 s−1) are used. Based on the flow stress data from temperatures and compressive strain rates, a processing map was developed. Processing efficiency is high below about 0.1 s−1 of strain rates and at almost all the temperatures, but reduced at 0.001 s−1 and 800°C because of the occurring of Shear band. Processing methods for optimal process are summarized on the basis of experimental findings. Bio-compatibility experiments indicated that Ti-10Ta-10Nb alloy is better than the control, Ti-6Al-4V alloy.

An effective loading method of the recombinant human Bone Morphogenetic Protein-2 (rhBMP-2) on the implant surface is essential for promoting bone formation. However, the studies comparing the effectiveness of loading methods for rhBMP-2 are insufficient. The objective of this study was to investigate the sustained rhBMP-2 delivery on the functionalized nanotubular surface. rhBMP-2 loading method on functionalized nanotubular surface was divided into 3 groups; coating and dry method, vacuum method, lyophilization method. A total of 10 ug rhBMP-2 was loaded into functionalized nanotubular titanium implant surfaces (3.75 mm in diameter and 7 mm in length). The releasing time of rhBMP-2 was evaluated at 1, 5, 7 days. The data were statistically analyzed with one-way ANOVA and a Post Hoc Bonferroni test. A sustained release pattern was observed in each groups and the amount of rhBMP-2 loaded was the highest in the lyophilization group. The results suggest that lyophilization method is effective method to load rhBMP-2 on the functionalized nanotubular surface and the functionalized nanotubular surface could be a sustainable useful carrier of rhBMP-2.

This study examined the bone response to titanium dioxide nanotube modified implants. A total of 24 implants were placed in the femur of 4 beagles. Before placement, screw-shaped implants were classified into 3 groups; machined surface (group M), titanium dioxide nanotube modification of the machined surface (group MN) and titanium dioxide nanotube modification of the RBM surface (group RN). The texture morphology was observed via scanning electron microscopy. Animals were euthanized after 4 and 12 weeks of submerged healing and the histologic and histomorphometric analyses were performed. Groups MN and RN showed a significantly higher percentage of mineralized bone than that in group M (p < 0.05). The results of this in vivo study constitute significant evidence that the presence of the titanium dioxide nanotubes enhance osseointegration of implants.

This article describes the use of a newly invented compound stick gun to take impressions for complete denture. The border molding process involves loading the modeling compound in an electric heating device and applying an even thickness of compound on the flange of a custom tray at a proper temperature without hot water tempering. This method provides a quicker and easier border molding process alternative to conventional techniques.

The aim of this study was to evaluate the response of Streptococcus mutans (S. mutans) via crystal violet staining assay on titanium surface modified by physical vapor deposition/plasma assisted chemical vapor deposition process. Specimens were divided into the following three groups: polished titanium (control group), titanium modified by DC magnetron sputtering (group TiN-Ti), and titanium modified by plasma nitriding (group N-Ti). Surface characteristics of specimens were observed by using nanosurface 3D optical profiler and field emission scanning electron microscope. Group TiN-Ti showed TiN layer of 1.2 microm in thickness. Group N-Ti was identified as plasma nitriding with X-ray photoelectron spectroscopy. Roughness average (Ra) of all specimens had valuesor = 0.2 microm (the threshold Ra), which had no effect on bacterial adhesion. No significant difference of S. mutans adhesion was found between the surfaces of control, TiN-Ti, and N-Ti (P0.05). Within the process condition of this study, modified titanium surfaces by DC magnetron sputtering and plasma nitriding did not influence the adhesion of S. mutans.

The objective of this study was to investigate the effects of nano-micro titanium implant surface using histology in beagle dogs. A total of 48 screw-shaped implants (Megagen, Daegu, Korea) which dimensions were 4 mm in diameter and 8.5 mm in length, were used. The implants were classified into 4 groups (n = 12): machined surface (M group), RBM (Resorbable Blasting Media) surface (R group), nano surface which is nanotube formation on the machined surface (MA group) and nano-micro surface which is nanotube formation on the RBM surface (RA group). Anodic oxidation was performed at a constant voltage of 20 V for 10 min using a DC power supply (Fine Power F-3005; SG EMD, Anyang, Korea). The bone blocks were investigated using histology. There was no inflammation around implants, and new bone formation was shown along with the nano-micro titanium implant surfaces. The amount of bone formation was increased depending on time comparing 4 weeks and 12 weeks. At 12 weeks, lamellar bone was more formed along with the nano-micro titanium implant surfaces than 4 weeks. It indicated that nano-micro surface showed good result in terms of osseointegration.

This study examined the effect of the immobilization of the Gly-Arg-Gly-Asp-Ser (GRGDS) peptide on titanium dioxide (TiO2) nanotube via chemical grafting on osteoblast-like cell (MG-63) viability and differentiation. The specimens were divided into two groups; TiO2 nanotubes and GRGDS-immobilized TiO2 nanotubes. The surface characteristics of GRGDS-immobilized TiO2 nanotubes were observed by using X-ray photoelectron spectroscopy (XPS) and a field emission scanning electron microscope (FE-SEM). The morphology of cells on specimens was observed by FE-SEM after 2 hr and 24 hr. The level of cell viability was investigated via a tetrazolium (XTT) assay after 2 and 4 days. Alkaline phosphatase (ALP) activity was evaluated to measure the cell differentiation after 4 and 7 days. The presence of nitrogen up-regulation or C==O carbons con- firmed that TiO2 nanotubes were immobilized with GRGDS peptides. Cell adhesion was enhanced on the GRGDS-immobilized TiO2 nanotubes compared to TiO2 nanotubes. Furthermore, significantly increased cell spreading and proliferation were observed with the cells grown on GRGDS-immobilized TiO2 nanotubes (P < .05). However, there was no significant difference in ALP activity between GRGDS-immobilized TiO2 nanotubes and TiO2 nanotubes. These results suggest that the GRGDS-immobilized TiO2 nanotubes might be effective in improving the osseointegration of dental implants.

The effect of three kinds of transition metal dopants on the color and biaxial flexural strength of zirconia ceramics for dental applications was evaluated. Presintered zirconia discs were colored through immersion in aqueous chromium, molybdenum and vanadium chloride solutions and then sintered at 1450 °C. The color of the doped specimens was measured using a digital spectrophotometer. For biaxial flexural strength measurements, specimens infiltrated with 0.3 wt% of each aqueous chloride solution were used. Uncolored discs were used as a control. Zirconia specimens infiltrated with chromium, molybdenum and vanadium chloride solutions were dark brown, light yellow and dark yellow, respectively. CIE L*, a*, and b* values of all the chromium-doped specimens and the specimens infiltrated with 0.1 wt% molybdenum chloride solution were in the range of values for natural teeth. The biaxial flexural strengths of the three kinds of metal chloride groups were similar to the uncolored group. These results suggest that chromium and molybdenum dopants can be used as colorants to fabricate tooth colored zirconia ceramic restorations.

The competition between green manure and forage crops frequently occurred at agricultural field because of soil fertility and livestock feeding selection. These experiments were carried out to evaluate the effects shoot and residue for green manure and forage production by leguminous crops and barley mixtures at paddy. Field experiments were conducted at paddy soil from 2008 to 2009. Treatments consisted of mixture and interseeding of barley and leguminous crops (hairy vetch and crimson clover). These treatments were divided into cutting height of 8 and 25 cm for using of green manure and forage at once. The residue biomass of 25 cm cutting height was higher than 8 cm and were no significantly between mixture and inter-seeding. However, residues of legume crop were significantly higher at inter-seeding than mixture. The shoot biomass of 8 cm cutting height was higher than 25 cm for forage using. The production of legume crop was high at the barley and hairy vetch seeding plot. The mixture of hairy vetch and barley showed the best biomass of shoot and residue for green manure and forage using at 25 cm of cutting height. Also this treatment could be possible to rice cultivation by no fertilization. Therefore, we suggested that 25 cm cutting of hairy vetch and barley mixture could be used for green manure and forage at the same time under rice-based cropping system.

Leguminous cover crops fix nitrogen from the atmosphere. The objective of this research was carried out to decrease fertilizer amount by cover crops-wheat mixtures cultivation. Field experiment was conducted at upland soil 2008 to 2009. Cover crops were used crimson clover and hairy vetch. Treatments consisted of three wheat-crimson clover (wheat 10 kg + crimson clover 1, 3, 5 kg 10a), wheat-hairy vetch mixture (wheat 10 kg + hairy vetch 2 kg 10a), and wheat hairy vetch mixture crimson clover (wheat 10 kg + hairy vetch 2 kg + crimson clover 3 kg 10a). These treatments were divided into no fertilizer and top dressing. The yield of wheat and crimson clover mixtures had no significantly differences compared to wheat only at top dressing plots. Also soil chemical and physical properties were a little bit improved such as OM, NO3-N, and bulk density etc by wheat-crimson clover mixtures. Therefore, we suggested that crimson clover and wheat mixture could be used to reduction of fertilizers amount for environmental friendly wheat production.

This study compared the removal torque between injection molded zirconia implants and titanium implants with resorbable blast media (RBM) surfaces in beagle humeri. Fifteen screw-shaped implants were classified into 3 groups; titanium implant with RBM surface (Group RT), injection molded zirconia implant (Group Zr) and injection molded zirconia implant with sand-blasted surface (Group ZrS). Implants were inserted into beagle humeri. After 12 weeks, removal torque values were measured. The Zr group has a slightly higher removal torque value than the RT and ZrS groups but there were no significant differences among groups. Zirconia implants shows a similar removal torque to RBM titanium implants. This in vivo study showed injection molded zirconia implants could be an alternative to RBM titanium implants in terms of removal torque.

PURPOSE The purpose of this study was to compare the linear sintering behavior of presintered zirconia blocks of various densities. The mechanical properties of the resulting sintered zirconia blocks were then analyzed. MATERIALS AND METHODS Three experimental groups of dental zirconia blocks, with a different presintering density each, were designed in the present study. Kavo Everest® ZS blanks (Kavo, Biberach, Germany) were used as a control group. The experimental group blocks were fabricated from commercial yttria-stabilized tetragonal zirconia powder (KZ-3YF (SD) Type A, KCM. Corporation, Nagoya, Japan). The biaxial flexural strengths, microhardnesses, and microstructures of the sintered blocks were then investigated. The linear sintering shrinkages of blocks were calculated and compared. RESULTS Despite their different presintered densities, the sintered blocks of the control and experimental groups showed similar mechanical properties. However, the sintered block had different linear sintering shrinkage rate depending on the density of the presintered block. As the density of the presintered block increased, the linear sintering shrinkage decreased. In the experimental blocks, the three sectioned pieces of each block showed the different linear shrinkage depending on the area. The tops of the experimental blocks showed the lowest linear sintering shrinkage, whereas the bottoms of the experimental blocks showed the highest linear sintering shrinkage. CONCLUSION Within the limitations of this study, the density difference of the presintered zirconia block did not affect the mechanical properties of the sintered zirconia block, but affected the linear sintering shrinkage of the zirconia block.

This study was to evaluate wettability, cell response, and osseointegration of nanotubular titanium (Ti) surface by anodic oxidation. Commercially pure Ti discs were treated by polishing, sandblasting, and anodizing. These surfaces were characterized by scanning electron microscopy and contact angle measurement. MC3T3-E1 osteoblast cell was used to evaluate cell response in vitro. The cell morphology, cell viability, and alkaline phosphatase (ALP) specific activity were assessed. The Ti implants of 2.0 mm diameter and 5.0 mm long treated by anodizing and sandblasting/anodizing were inserted into the tibia of rats. After 3 weeks, the histology of the Ti–bone interface was examined. SEM observations showed that the anodizing and sandblasting/anodizing created the nanotubular surface and graded nanotubular-micro-roughened surfaces, respectively. The anodizing and sandblasting/anodizing significantly improved the hydrophilicity of Ti. The significant greatest cell spreading and ALP specific activity were observed on the graded nanotubular-micro-roughened surfaces treated by sandblasting/anodizing. The in vivo study shows that newly formed bone was intimately in contact with the nanotubular surfaces without adverse immune response. This study has suggested that the graded nanotubular-micro-roughened surface of Ti treated with sandblasting/anodizing is very promising in implantology due to improved hydrophilicity, favorable cell response, and excellent osseointegration.

article i nfo The objective of this study was to determine the effects of coating titanium with Au or TiN on its adhesion to dental porcelain. Cast and machined ASTM grade II CP titanium samples that were either uncoated, coated with Au, or coated with TiN were examined. The specimen surfaces were characterized by SEM/EDS and XRD. An ultra-low-fusing dental porcelain (Vita Titankeramik) was fused onto the titanium surfaces. Biaxial flexure tests and X-ray spectroscopy, the latter of which was used to determine the area fraction of adherent porcelain (AFAP), were performed to characterize the titanium-ceramic adhesion. The TiN-coated surfaces (prepared by arc ion plating) exhibited well-networked surface structures with small dimples on their Ti surfaces. The surface morphologies of the Au-coated samples were similar to those of the uncoated titanium surfaces. The AFAP value for the machined titanium was independent of the surface treatment. All of the cast and machined titanium samples had similar AFAP values, except for the uncoated cast titanium, which had a significantly lower AFAP value. On the surfaces of the gold-coated cast and machined titanium samples, a new Au2Ti phase with a tetragonal structure was identified. The improved adherence between the porcelain and commercially pure titanium upon coating the latter with Au or TiN is of great clinical importance.

Hydroxyapatite (HA) coating on titanium dioxide (TiO2) nanotubular surface has been developed to complement the defects of both TiO2 and HA. A sol-gel processing technique was used to coat HA on TiO2 nanotubular surface. All the titanium discs were blasted with resorbable blast media (RBM). RBM-blasted Ti surface, anodized Ti surface, and sol-gel HA coating on the anodized Ti surface were prepared. The characteristics of samples were observed using scanning electron microscopy and X-ray photoemission spectroscopy. Biologic responses were evaluated with human osteosarcoma MG63 cells in vitro. The top of the TiO2 nanotubes was not completely covered by HA particles when the coating time was less than 60 sec. It was demonstrated the sol-gel derived HA film was well-crystallized and this enhanced biologic responses in early stage cell response.

This study evaluated the antibacterial effect of a visible light reactive TiO2/Ag nanocomposite thin film on dental orthodontic wire (STS 304 wire). The growth of S. mutans and A. actinomycetemcomitans was suppressed on the specimens coated with TiO2/Ag compared to the uncoated specimens. The antibacterial effect of the TiO2/Ag nanocomposite thin film was improved under visible light irradiation.

PURPOSE: This study was to evaluate the marginal fit of two CAD-CAM anatomic contour zirconia crown systems compared to lithium disilicate glass-ceramic crowns. MATERIALS AND METHODS: Shoulder and deep chamfer margin were formed on each acrylic resin tooth model of a maxillary first premolar. Two CAD-CAM systems (Prettau®Zirconia and ZENOSTAR®ZR translucent) and lithium disilicate glass ceramic (IPS e.max®press) crowns were made (n=16). Each crown was bonded to stone dies with resin cement (Rely X Unicem). Marginal gap and absolute marginal discrepancy of crowns were measured using a light microscope equipped with a digital camera (Leica DFC295) magnified by a factor of 100. Two-way analysis of variance (ANOVA) and post-hoc Tukey's HSD test were conducted to analyze the significance of crown marginal fit regarding the finish line configuration and the fabrication system. RESULTS: The mean marginal gap of lithium disilicate glass ceramic crowns (IPS e.max®press) was significantly lower than that of the CAD-CAM anatomic contour zirconia crown system (Prettau®Zirconia) (P

Although the application of zirconia in esthetic prostheses has increased, the shear bond strength (SBS) between colored zirconia and resin cement has not been investigated.The purpose of this study was to compare the SBS between resin cement and colored zirconia made with metal chlorides.Sixty-four zirconia specimens were divided into 2 groups: one in which the specimens were bonded with resin cement, including 4-META (4-methacryloxyethyl trimellitic anhydride), and one in which the specimens were bonded with resin cement (SEcure, Sun Medical) after being processed with zirconia primer (Zirconia Liner), including 4-META. Each group was then divided into 4 subgroups depending on the coloring liquid. The subgroups were noncolored (control), commercial coloring liquid VITA In-Ceram 2000 YZ LL1, aqueous chromium chloride solution 0.1 wt%, and aqueous molybdenum chloride solution 0.1 wt%. Composite resin cylinders (Filtek Z250, 3M ESPE) were fabricated and bonded to the surface of the zirconia specimen with resin cement (SEcure). All specimens were stored in 37°C distilled water for 24 hours, and the SBS was measured with a universal testing machine. All data were analyzed statistically with 2-way ANOVA and tested post hoc with the Tukey test (α=.05).Significant differences were observed among the SBS values of the colored zirconia depending on the coloring liquid (P.001) and whether they were processed with zirconia primer (P.001). The SBS between colored zirconia and resin cement was significantly higher than that of noncolored zirconia and resin cement in groups processed with zirconia primer (P.05). Colored zirconia immersed in aqueous molybdenum chloride solution showed a significantly higher SBS.Coloring liquid enhanced the SBS between resin cement and zirconia processed with zirconia primer. In particular, colored zirconia immersed in aqueous molybdenum chloride solution showed the highest SBS.