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1.
Journal of Korean Dental Science ; : 10-21, 2017.
Article in English | WPRIM | ID: wpr-25855

ABSTRACT

PURPOSE: The purpose of this study was to investigate the electrochemical characteristics of nanotubular Ti-25Nb-xZr ternary alloys for dental implant materials. MATERIALS AND METHODS: Ti-25Nb-xZr alloys with different Zr contents (0, 3, 7, and 15 wt.%) were manufactured using commercially pure titanium (CP-Ti), niobium (Nb), and zirconium (Zr) (99.95 wt.% purity). The alloys were prepared by arc melting in argon (Ar) atmosphere. The Ti-25Nb-xZr alloys were homogenized in Ar atmosphere at 1,000℃ for 12 hours followed by quenching into ice water. The microstructure of the Ti-25Nb-xZr alloys was examined by a field emission scanning electron microscope. The phases in the alloys were identified by an X-ray diffractometer. The chemical composition of the nanotube-formed surfaces was determined by energy-dispersive X-ray spectroscopy. Selforganized TiO₂ was prepared by electrochemical oxidation of the samples in a 1.0 M H₃PO₄+0.8 wt.% NaF electrolyte. The anodization potential was 30 V and time was 1 hour by DC supplier. Surface wettability was evaluated for both the metallographically polished and nanotube-formed surfaces using a contact-angle goniometer. The corrosion properties of the specimens were investigated using a 0.9 wt.% aqueous solution of NaCl at 36℃±5℃ using a potentiodynamic polarization test. RESULT: Needle-like structure of Ti-25Nb-xZr alloys was transform to equiaxed structure as Zr content increased. Nanotube formed on Ti-25Nb-xZr alloys show two sizes of nanotube structure. The diameters of the large tubes decreased and small tubes increased as Zr content increased. The lower contact angles for nanotube formed Ti-25NbxZr alloys surfaces showed compare to non-nanotube formed surface. The corrosion resistance of alloy increased as Zr content increased, and nanotube formed surface showed longer the passive regions compared to non-treatment surface. CONCLUSION: It is confirmed that corrosion resistance of alloy increased as Zr content increased, and nanotube formed surface has longer passive region compared to without treatment surface.


Subject(s)
Alloys , Argon , Atmosphere , Corrosion , Dental Implants , Freezing , Ice , Nanotubes , Niobium , Spectrum Analysis , Titanium , Water , Wettability , Zirconium
2.
Journal of the Korean Ophthalmological Society ; : 1877-1880, 2009.
Article in Korean | WPRIM | ID: wpr-96503

ABSTRACT

PURPOSE: To report a case of keratoconjunctivitis induced by Dieffenbachia plant sap. CASE SUMMARY: A 44-year-old woman presented with severe ocular pain and decreased visual acuity which developed after she accidentally got Dieffenbachia plant sap in her left eye. During her initial evaluation, visual acuity was 0.4 in her left eye. On slit lamp examination, we found that she had moderate injection of the conjunctiva, an epithelial defect, and fine needle-like blue crystals in the stromal layer of the cornea. The patient was treated with topical steroids and antibiotics. We checked the treatment response using a regular slit lamp examination. Six days after the injury, all of the findings which were observed on the first day had resolved except the needle-like blue crystals in the stromal layer of the cornea. These gradually disappeared from the cornea 11 days after the accident. After six weeks, the crystals in the stromal layer had completely resolved. She maintained good visual acuity during this time. There was no opacity noted in her cornea. CONCLUSIONS: We experienced a case of keratoconjunctivitis induced by Dieffenbachia plant sap. This sap caused severe ocular pain and a reversible decrease in visual acuity when in contact with the eye.


Subject(s)
Adult , Female , Humans , Anti-Bacterial Agents , Conjunctiva , Cornea , Eye , Keratoconjunctivitis , Plants , Steroids , Visual Acuity
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