ABSTRACT
In this study, the Ti6Al4V specimens were fabricated using selective laser melting (SLM) method (Ti6Al4V-AS group). These specimens were performed to heat treatment at 950℃ and 550℃ using vacuum electric furnace (Ti6Al4V-HT group). The mechanical properties, metallographic shape, crystalline structure, and chemical compositions of the alloy specimens before and after heat treatment were analyzed. The Ti6Al4V-AS group showed ultimate tensile strength (UTS) and low elongation values. Acicular crystal grains were observed in metallographic image and the α'-Ti phase was dominant. After heat treatment (Ti6Al4V-HT group), the UTS was lowered and the elongation was increased. In addition, a lamellar structure in which columnar crystal grains are arranged was observed, α+β-Ti phase was formed, and crystallinity increased. As a result of analyzing the chemical composition, the Ti6Al4V-AS specimen contained a higher carbon content than the Ti6Al4V-HT specimen. This high carbon content could be related to the formation of α'-phase, high strength and low elongation of the Ti6Al4V-AS specimen. Ti6Al4V-HT specimen showed that the overall carbon content was low, but the carbon content was locally high in the α-Ti phase region. Therefore, it is necessary to control effectively the incorporation of carbon gas in the production of Ti6Al4V specimens using SLM.
ABSTRACT
In this study, a biomimetic coating in which hydroxyapatite (HAp) and collagen (Col), the major components of bone, were coated together on titanium was performed using the ECD method. The polished CP-Ti (commocially pure–titanium) disks (Ti-As), and the roughened CP-Ti disks (Ti-R) fabricated by anodic oxidation method were prepared. An electrolyte (E) was prepared by mixing Ca(NO 3 ) 2 and NH 4 H 2 PO 4 . Collagen-contaiing electrolyte (ECol) was prepared by adding collagen (Type-I) to E electrolyte. A pulse-type negative electric current of -5 mA, -10 mA, and -15 mA was applied to the titanium specimens, respectively.The temperature of electrolyte solution was maintained at 37℃. The fabricated specimens were named to Ti-As-E-5, Ti-As-E-10, Ti-As-E-15, Ti-As-ECol-5, Ti-As-ECol-10, Ti-As-ECol-15, Ti-R-E-5, Ti-R-E-10, Ti-R-E-15, Ti-R-ECol-5, Ti-R-ECol-10, and Ti-R-ECol-15, respectively. The nanorod-shaped crystallites were evenly formed on the surface of Ti-As-E groups. The length of nanorods on Ti-As-ECol groups was shorter than that on Ti-As-E groups. A low crystalline HAp structure was detected in X-ray diffraction (XRD) patterns of Ti-As-E groups. For Ti-As-ECol groups, the HAp structure was confirmed by analysis of the selected area electron diffraction (SAED) patterns obtained from a transmission electron microscope (TEM). Fourier-transform infrared spectroscopy (FT-IR) spectra of Ti-As-ECol groups showed the amide peaks assigned to collagen and related to carbonate apatite. Similarly to the Ti-As specimens, HAp crystallites were coated on Ti-R-E and Ti-R-ECol groups and their surface roughness was maintained. It is expected that the results of this study could be applied to the development of a biomimetic surface treatment method for titanium implants.
ABSTRACT
The long setting time of dental MTA (Mineral Trioxide Aggregate) cement is a major disadvantage in clinical use. In this study, the setting time (ST) of nine commercial MTA cements was tested according to the ISO 6876:2012 standard (n = 5).Materials evaluated were ProRoot MTA (PR), Ortho MTA (Ortho), Retro MTA (Retro), Endocem MTA (Endocem), Endoseal MTA (Endoseal), One-Fil (OF), MTA Cem (MC), EZ-Seal (EZ), and Biodentine (BD). XRD and XRF analysis were performed to evaluate the effect of composition on ST. Kruskal-Wallis test as a non-parametric ANOVA followed by Duncan’s post hoc test was used for statistical analysis. The ST was PR > EZ > OF > Ortho > Retro > MC > Endoseal > BD > Endocem in decreasing order (p < 0.001). PR showed the longest (369.4 min) and Endocem showed the shortest (2.4 min) ST. Endocem (2.4 min), BD (16.0 min) and Endoseal (47.0 min) contained calcium carbonate. MC (48.8 min), Retro (43.6 min), Ortho (65.0), and OF (165.4 min), which had the next short setting time, contained dicalcium aluminate. In EZ (182.4 min), dicalcium silicate was the main crystalline phase rather than tricalcium silicate, which contributes to the early strength, and it contained calcium sulfate. Endocem, which showed the shortest setting time, showed the smallest d90 particle size of 6.12 µm. The information obtained from this study would be helpful in developing a composition for controlling the setting time of MTA cement and selecting a product with a setting time suitable for each clinical case.
ABSTRACT
In this study, the hydroxyapatite (HAps) containing bovine serum albumin (BSA) were coated on titanium using the electrochemical deposition (ECD) method. Negative electric current pulses were applied to titanium specimens at 37 ℃ using a Ca- and P-containing electrolyte in which BSA was added E-BSA-10, E-BSA-15, and E-BSA-20 groups were prepared by changing the electric current to –10 mA, –15 mA, and –20 mA, respectively. As a comparative group, an E-15 specimen was prepared by applying a current of -15 mA to the specimen in Ca- and P-containing electrolyte without BSA. A coating film composed of nanosheet-shaped crystals was observed on the surface of each specimen, and the size of the nanocrystals on the BSA-containing groups was larger than that of the E-15 group. These crystals were smaller in size and higher in density as the applied current values were increased. All specimens had HAp crystalline structure. BSA-containing specimens showed a tendency of preferential growth of HAp crystals in c-axis orientation, and this tendency decreased as the applied current values were increased. In the FT-IR spectrum, amide peaks that corresponds to BSA were identified. As a result of soaking the BSA-containing group specimens in phosphate-buffered saline (PBS) for 60 hours, it was observed that the crystal structure aligned with the c-axis was disordered, and BSA was released slowly with the decomposition of HAp. This study is expected to be applied to the development of a surface treatment method for coating titanium implants with HAp containing various biological factors in the future.
ABSTRACT
The effects of the conditions of microarc oxidation (MAO) and hydrothermal treatments on the formation of micro-nano hybrid surface on titanium has been studied. Titanium metals were microarc oxidized using the electrolyte containing Ca and P ions for 30, 60, 120, 180, and 240 s, respectively. These MAO-treated specimens were hydrothermally treated using alkaline solution (HT-treatment) or P-containing alkaline solution (HTP-treatment). The porous morphology was appeared after MAO treatment for more than 60 s. The Ca and P ions in oxide layer were detected clearly after MAO treatment for 120 s, and their contents increased as MAO-treatment time increased. After hydrothermal treatment, micro-sized hydroxyapatite (HAp) and nano-sized TiO2 crystallites were formed on porous surfaces. The size of HAp crystallites formed by HTP-treatment was larger than that formed by HT-treatment, while the size of TiO2 crystallites showed the opposite tendency. Surface roughness of MAO-treated groups increased with MAO-treatment time. After hydrothermal treatment, the roughnesses of the specimens MAO-treated for 30 and 60 s decreased, while the roughness increased after MAO treatment for 120 s. The hydrophilicity of MAO-treated specimens increased with MAO-treatment time. The hydrophilicity of the specimens MAO-treated for 30 and 60 s decreased after hydrothermal treatment. However, the hydrophilicity of the specimens treated with MAO over 120 s and subsequent HT- or HTP- treatments increased with the formation of HAp on their surfaces.
ABSTRACT
The long setting time of dental MTA (Mineral Trioxide Aggregate) cement is a major disadvantage in clinical use. In this study, the setting time (ST) of nine commercial MTA cements was tested according to the ISO 6876:2012 standard (n = 5).Materials evaluated were ProRoot MTA (PR), Ortho MTA (Ortho), Retro MTA (Retro), Endocem MTA (Endocem), Endoseal MTA (Endoseal), One-Fil (OF), MTA Cem (MC), EZ-Seal (EZ), and Biodentine (BD). XRD and XRF analysis were performed to evaluate the effect of composition on ST. Kruskal-Wallis test as a non-parametric ANOVA followed by Duncan’s post hoc test was used for statistical analysis. The ST was PR > EZ > OF > Ortho > Retro > MC > Endoseal > BD > Endocem in decreasing order (p < 0.001). PR showed the longest (369.4 min) and Endocem showed the shortest (2.4 min) ST. Endocem (2.4 min), BD (16.0 min) and Endoseal (47.0 min) contained calcium carbonate. MC (48.8 min), Retro (43.6 min), Ortho (65.0), and OF (165.4 min), which had the next short setting time, contained dicalcium aluminate. In EZ (182.4 min), dicalcium silicate was the main crystalline phase rather than tricalcium silicate, which contributes to the early strength, and it contained calcium sulfate. Endocem, which showed the shortest setting time, showed the smallest d90 particle size of 6.12 µm. The information obtained from this study would be helpful in developing a composition for controlling the setting time of MTA cement and selecting a product with a setting time suitable for each clinical case.
ABSTRACT
In this study, the hydroxyapatite (HAps) containing bovine serum albumin (BSA) were coated on titanium using the electrochemical deposition (ECD) method. Negative electric current pulses were applied to titanium specimens at 37 ℃ using a Ca- and P-containing electrolyte in which BSA was added E-BSA-10, E-BSA-15, and E-BSA-20 groups were prepared by changing the electric current to –10 mA, –15 mA, and –20 mA, respectively. As a comparative group, an E-15 specimen was prepared by applying a current of -15 mA to the specimen in Ca- and P-containing electrolyte without BSA. A coating film composed of nanosheet-shaped crystals was observed on the surface of each specimen, and the size of the nanocrystals on the BSA-containing groups was larger than that of the E-15 group. These crystals were smaller in size and higher in density as the applied current values were increased. All specimens had HAp crystalline structure. BSA-containing specimens showed a tendency of preferential growth of HAp crystals in c-axis orientation, and this tendency decreased as the applied current values were increased. In the FT-IR spectrum, amide peaks that corresponds to BSA were identified. As a result of soaking the BSA-containing group specimens in phosphate-buffered saline (PBS) for 60 hours, it was observed that the crystal structure aligned with the c-axis was disordered, and BSA was released slowly with the decomposition of HAp. This study is expected to be applied to the development of a surface treatment method for coating titanium implants with HAp containing various biological factors in the future.
ABSTRACT
The effects of the conditions of microarc oxidation (MAO) and hydrothermal treatments on the formation of micro-nano hybrid surface on titanium has been studied. Titanium metals were microarc oxidized using the electrolyte containing Ca and P ions for 30, 60, 120, 180, and 240 s, respectively. These MAO-treated specimens were hydrothermally treated using alkaline solution (HT-treatment) or P-containing alkaline solution (HTP-treatment). The porous morphology was appeared after MAO treatment for more than 60 s. The Ca and P ions in oxide layer were detected clearly after MAO treatment for 120 s, and their contents increased as MAO-treatment time increased. After hydrothermal treatment, micro-sized hydroxyapatite (HAp) and nano-sized TiO2 crystallites were formed on porous surfaces. The size of HAp crystallites formed by HTP-treatment was larger than that formed by HT-treatment, while the size of TiO2 crystallites showed the opposite tendency. Surface roughness of MAO-treated groups increased with MAO-treatment time. After hydrothermal treatment, the roughnesses of the specimens MAO-treated for 30 and 60 s decreased, while the roughness increased after MAO treatment for 120 s. The hydrophilicity of MAO-treated specimens increased with MAO-treatment time. The hydrophilicity of the specimens MAO-treated for 30 and 60 s decreased after hydrothermal treatment. However, the hydrophilicity of the specimens treated with MAO over 120 s and subsequent HT- or HTP- treatments increased with the formation of HAp on their surfaces.
ABSTRACT
It is difficult to get sufficient roughness on titanium implant surface using traditional electrochemical treatments. In this study, we have developed a new method which provides a hybrid structured titanium surface having micro/nano roughness using electrochemical treatment in NaCl electrolyte and hydrothermal treatment. Titanium disks were anodically oxidized (ANO) in 0.15M NaCl electrolyte by applying positive electric pulses. The oxide compounds loosely attached to the surface were removed by ultrasonic cleaning (ANO group). These specimens were hydrothermally (HT) treated in an alkaline solution (ANO-HT group). ANO group showed the dimpled grain surfaces with a diameter of approximately 30 µm, and its roughness (Ra) was about 2.4 µm. The nano-sized crystallites which had an anatase TiO₂ crystalline structure were uniformly distributed on the surface of ANO-HT group. This group still retained high roughness (~2.7 µm) similar to ANO group and showed high hydrophilicity. Titanium surface with high roughness and hydrophilicity was fabricated using new electrochemical treating method and hydrothermal treatment. This surface modification method could be used for enhancing the osteoconductivity of the titanium implants.
Subject(s)
Crystallins , Hydrophobic and Hydrophilic Interactions , Methods , Titanium , UltrasonicsABSTRACT
In this study, hydroxyapatite (HAp) was coated on titanium using electrochemical deposition (ECD) method at body fluid temperature. The titanium specimens for ECD were prepared by chemically etching treatment using 5M NaOH solution. The electrolyte mixed with 5 mM Ca(NO³)² and 2 mM NH⁴H²PO⁴ which has pH 5 (E2) was adjusted to pH 3 (E1) and pH 6 (E3). The different electric pulses of −10, −15, −30 mA were applied to each specimen. The temperature of electrolytes was kept at 37℃. E1-10, E1-15, E1-30, E2-10, E2-15, E2-30, E3-10, E3-15, and E3-30 groups were prepared for this study. Scanning electron microscope (SEM) images showed that E1-10 and E1-15 groups were not coated and the powder-shaped compounds were formed on E3-15 and E3-30 groups. The cracks were observed on the surface of E1-30 and E2-30 groups. The evenly and stable coated layer was deposited on E2-10, E2-15 and E3-10 groups. The layer coated on titanium surface had an HAp crystalline structure. E1-30 and E2-30 groups had low crystallinity, even though they had thick layer. HAp layer on for E2-10 group was well deposited on the surface because it more aligned to c-axis compared with other groups.
Subject(s)
Body Fluids , Crystallins , Durapatite , Electrolytes , Hydrogen-Ion Concentration , Methods , TitaniumABSTRACT
OBJECTIVE@#To investigate the mechanism of antibacterial activity of luteolin (LUT) against methicillin-resistant Staphylococcus aureus (MRSA).@*METHODS@#The mechanism of anti-MRSA activity of LUT was analyzed by the viability assay in membrane permeabilizing agent, ATPase inhibitors, and peptidoglycan (PGN) derived from Staphylococcus aureus (S. aureus). Also, transmission electron microscopy was used to monitor survival characteristics and changes in S. aureus morphology.@*RESULTS@#Compared to the LUT alone, the optical density of suspensions treated with the combination of 125 μg/mL Tris and 250 μg/mL N,N'-dicyclohexylcarbodiimide were reduced to 60% and 46% of the control, respectively. PGN (15.6 μg/mL) gradually impeded the activity of LUT, and PGN (62.5 μg/mL) completely blocked the activity of LUT on S. aureus.@*CONCLUSIONS@#Increased susceptibility to LUT with the Tris-dicyclohexylcarbodiimide combinations is evident in all tested MRSA isolates. The results indicate LUT synergy in increasing cytoplasmic membrane permeability and inhibiting ATPase. S. aureus PGN directly blocks the antibacterial activity of LUT, suggesting the direct binding of LUT with PGN. These findings may be validated for the development of antibacterial agent for low MRSA resistance.
ABSTRACT
Objective: To investigate the mechanism of antibacterial activity of luteolin (LUT) against methicillin-resistant Staphylococcus aureus (MRSA). Methods: The mechanism of anti-MRSA activity of LUT was analyzed by the viability assay in membrane permeabilizing agent, ATPase inhibitors, and peptidoglycan (PGN) derived from Staphylococcus aureus (S. aureus). Also, transmission electron microscopy was used to monitor survival characteristics and changes in S. aureus morphology. Results: Compared to the LUT alone, the optical density of suspensions treated with the combination of 125 μg/mL Tris and 250 μg/mL N,N'-dicyclohexylcarbodiimide were reduced to 60% and 46% of the control, respectively. PGN (15.6 μg/mL) gradually impeded the activity of LUT, and PGN (62.5 μg/mL) completely blocked the activity of LUT on S. aureus. Conclusions: Increased susceptibility to LUT with the Tris-dicyclohexylcarbodiimide combinations is evident in all tested MRSA isolates. The results indicate LUT synergy in increasing cytoplasmic membrane permeability and inhibiting ATPase. S. aureus PGN directly blocks the antibacterial activity of LUT, suggesting the direct binding of LUT with PGN. These findings may be validated for the development of antibacterial agent for low MRSA resistance.
ABSTRACT
PURPOSE: The antibiotic sensitivities to the causative microorganisms of urinary tract infection (UTI) during 2003 were studied in order to propose a better choice of adequate drugs for the treatment of UTI. MATERIALS AND METHODS: 1,527 uropathogens and their antimicrobial sensitivities, in 889 patients admitted to or visiting our hospital during 2003, which revealed isolated causative organisms in the urine cultures, were analyzed. RESULTS: The incidence of UTI was highest in the 7th decade. The Most common pathogenic organism was E. coli (46.4%), followed by Enterococcus (18.8%), Pseudomonas (7.1%), Klebsiella (5.7%) and Staphylococcus (4.5%). The antimicrobial sensitivities for gram-negative organisms, imipenem, aminoglycoside, ciprofloxacin showed relatively higher sensitivities than for TMP/SMX and ampicillin. In gram-positive organisms, vancomycin and aminoglycoside showed higher sensitivities than any of the other antimicrobial agents. Most of the antimicrobial agents had better sensitive rates in the outpatients. CONCLUSIONS: E. coli was the most common single organism causing UTI, and showed more resistance to the first recommended drugs, TMP/SMX and ampicillin. Our results imply that recommended the drugs for UTI should be aminoglycoside and ciprofloxacin for inpatients and outpatients, respectively. Aminoglycoside can be used as an alternative to these drugs as a primary empirical antimicrobial agents for UTI.
Subject(s)
Humans , Ampicillin , Anti-Bacterial Agents , Anti-Infective Agents , Ciprofloxacin , Enterococcus , Imipenem , Incidence , Inpatients , Klebsiella , Outpatients , Pseudomonas , Staphylococcus , Urinary Tract Infections , Urinary Tract , VancomycinABSTRACT
BACKGROUND/AIMS: Infliximab has been shown to be effective and safe for treating refractory luminal and fistulizing Crohn's disease (CD). The aim of this study was to report the efficacy and adverse effect of infliximab therapy in patients with CD at our center. METHODS: Medical records of thirteen patients who were treated with infliximab for refractory luminal or fistulizing CD were reviewed. Clinical response was classified as complete response, partial response and nonresponse. RESULTS: Seven patients were treated for fistulizing CD, four patients for luminal CD, and two for both. The mean time of follow-up was 13.1 months (3.3-28.1 months). Clinical response was seen in 10/13 (77%); complete response 7/13 (54%), partial response 3/13 (23%), nonresponse 3/13 (23%). Mean time to response was 27.1 days (10-41 days). 4 of 10 responders (40%) maintained remission over 30 weeks. Those who started on immunosuppressive treatment more than 3 months before infliximab infusion achieved lower early recurrence rate (14%) compared with those less than 3 months (67%) (p=0.039). Steroid tapering was successful in 7/12 (58%). Five patients required surgical therapy; three nonresponders, one partial responder and one who recurred after initial complete response. Initial responders required less surgery than nonresponders (p=0.035). Acute infusion reactions were seen in 2/40 infusions (5%). One patient developed herpes zoster 20 weeks after infliximab infusion. During follow-up peried, no patient developed serious infection, tuberculosis or malignancy. CONCLUSIONS: Infliximab is effective and safe in clinical practice. Concurrent immunosuppressive use is associated with lower rate of early recurrence.
Subject(s)
Adult , Female , Humans , Male , Antibodies, Monoclonal/adverse effects , Crohn Disease/drug therapy , Gastrointestinal Agents/adverse effects , Immunosuppressive Agents/therapeutic useABSTRACT
Malacoplakia is a rare granulomatous inflammatory disease, which most frequently involves the urinary tract and especially the urinary bladder. The prostatic involvement of malacoplakia is rare and only two cases have been reported in the Korean literature. Malacoplakia of the prostate may clinically mimic prostate cancer or chronic prostatitis. We report a case of malacoplakia of the prostate in a 71-year-old man, which was initially misdiagnosed as prostate cancer or prostatitis.
Subject(s)
Aged , Humans , Malacoplakia , Prostate , Prostatic Neoplasms , Prostatitis , Urinary Bladder , Urinary TractABSTRACT
Although there are many reports of concomitant urinary and reproductive system malformations, a review of the literature shows these unique associations in a single patient are extremely rare. We report here on a case of unilateral partial duplicated vaginal ectopic ureter with ipsilateral dysplastic kidney and uterine didelphys in an 11 years old female patient who has suffered from persistent urinary incontinence since birth. The embryological aspects as well as the clinical presentation, diagnostic approach and treatment applicable for this group of patients are discussed.
Subject(s)
Child , Female , Humans , Kidney , Multicystic Dysplastic Kidney , Parturition , Ureter , Urinary Incontinence , Uterus , VaginaABSTRACT
Although there are many reports of concomitant urinary and reproductive system malformations, a review of the literature shows these unique associations in a single patient are extremely rare. We report here on a case of unilateral partial duplicated vaginal ectopic ureter with ipsilateral dysplastic kidney and uterine didelphys in an 11 years old female patient who has suffered from persistent urinary incontinence since birth. The embryological aspects as well as the clinical presentation, diagnostic approach and treatment applicable for this group of patients are discussed.
Subject(s)
Child , Female , Humans , Kidney , Multicystic Dysplastic Kidney , Parturition , Ureter , Urinary Incontinence , Uterus , VaginaABSTRACT
Pneumonia is a fatal disease in immunocompromised patients including bone marrow transplantation recipients. Etiological agents include fungi, cytomegalovirus, Pneumocystis carinii, influenza virus and parainfluenza virus. We describe a community-acquired respiratory syncytial virus pneumonia in a patient who received intense chemotherapy followed by peripheral stem cell transplantation for acute leukemia. The patient was treated with intravenous immunoglobulin and ribavirin aerosol. About 1 month later, she was recovered.