• The Journal of Advanced Prosthodontics
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• 제1권1호
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• pp.10-18
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• 2009

STATEMENT OF PROBLEM. Despite an improved bone reactions of Mg-incorporated implants in the animals, little yet has been carried out by the experimental investigations in functional loading conditions. PURPOSE. This study investigated the clinical and histologic parameters of osseointegrated Mg-incorporated implants in early loading conditions. MATERIAL AND METHODS. A total of 36 solid screw implants(diameter 3.75 mm, length 10 mm) were placed in the mandibles of 6 beagle dogs. Test groups included 18 Mg-incorporated implants. Turned titanium implants served as control. Gold crowns were inserted 4 weeks after implant placement and the dogs were immediately put on a food diet. Implants were observed for 10 weeks after loading. Radiographic assessments and stability tests were performed at the time of fixture installation, $2^{nd}$ stage surgery, 4 weeks after loading, and 10 weeks after loading. Histological observations and morphometrical measurements were also performed. RESULTS. Of 36 implants, 33 displayed no discernible mobility, corresponding to successful clinical function. There was no statistically significant difference between test implants and controls in marginal bone levels(P=.46) and RFA values. The mean BIC % in the Mg-implants was $54.5{\pm}8.4%$. The mean BIC % in the turned implant was $45.3{\pm}12.2%$. These differences between the Mg-implant and control implant were statistically significant(P=.005). CONCLUSIONS. The anodized, Mg-incorporated implant demonstrated significantly more bone-to-implant contact(BIC) in early loading conditions. CLINICAL IMPLICATIONS. The results of this study in beagle dogs suggest the possibility of achieving predictable stability of early loaded free-standing dental implants with Mg-incorporated surface.

• 대한치과보철학회지
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• 제43권1호
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• pp.78-94
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• 2005

Purpose. The purpose of this study was to compare the effects of various surface treatments by measuring resonance frequency and histomorphometric analyses. Material and methods. In 5 adult dogs, the mandibular premolar were extracted. Six months later, 30 screw titanium implants (Dentium Co., Seoul, Korea) 6mm in length and 3.4mm in diameter, were placed in the mandibles of 5 dogs. Implants were divided into five groups following to surface treatment methods ; Group 1 is machined controls, Group 2 is sandblasted with large grit and acid-etched (SLA), Group 3 is anodized (Autoelectric Co., Korea, 660Hz, Duty10), Group 4 is hydroxyapatite(HA) coated by ion beam assisted deposition(E-beam), Group 5 is hydroxyapatite(HA) coated with Sol-gel coating process. Resonance frequency was measured implant placement immediately, and 3, 6 weeks and 10 weeks of healing perods. With the animal subject's sacrifice 10 weeks after implantation, implants were removed on bloc and histologic and computer-based histomorphometric analyses were performed. Histomorphometric analysis involved quantification of the entire bone to metal contact around the implants. Statistical analyses were performed using the SPSS for Windows (ver. 9.0 SPSS Inc.) Statistical differences were considered significant at P<0.05. Results. The results were as follows : 1) In five groups, mean value of resonance frequency analysis(RFA) were highest in group 5 (Sol-gel implant) at implantation and those of group 4 (E-beam)was highest at 10 weeks . but there was no correlation between surface treatments and RFA. 2) In all surface treatment groups, the RFA values of implants decreased until 3 weeks and increased to 10 weeks. 3) The percentage of direct bone-to-implant contact (BIC) had statistical significance between five groups in cancellous bone, (P<0.05) the percentage of bone density inside the thread had no statistical significance between five groups. (P>0.05) 4) There was a significant difference between cortical bone and cancellous bone in BIC. (P<0.05) and bone density. (P<0.05) 5) There was a correlation between the RFA value of implants at 10 weeks and BIC in cancellous bone, and between the RFA value of implants at 10 weeks and bone density in cortical bone. (P<0.05). Conclusions. These results indicate that surface treatment does not affect the implant stability in case of good bone quality.

• 대한치과보철학회지
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• 제45권3호
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• pp.362-374
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• 2007

Statement of problem. The intial stability for osseointegration of implant has been an interesting factor. Especially, in the case of poor bone quality or immediately loaded implant, various strategies have been developed focusing on the surface of materials to improve implant fixation to bone. The microscopic properties of implant surfaces play a major role in the osseous healing of dental implants. Purpose. The aims of this study are to perform a histologic and histomorphometric comparison of the healing characteristics of three different surfaces and the comparison of resonance frequency analysis (RFA) values measured by $Osstell^{TM}$ and perio-test values (PTV) measured by Periotest. Material and methods. A total of 24 screw titanium implants (Dentium Co., Seoul, Korea) with 6mm in length and 3.4mm in diameter, were placed in the mandible of 4 beagle dogs. Implants were divided into three groups following the surface treatment methods: Group I is machined(control group). Group II is anodically oxidized. Group III is coated 500nm in thickness with hydroxyapatite(HA) by ion beam assisted deposition(IBAD) on the anodized oxidization. Bone blocks from 2 dogs were caught after 3 weeks of covered healing and another blocks from 2 dogs after 6 weeks. RFA values and PTV were measured right after insertion and at 3 and 6weeks. Histomorphometric analysis was made with Kappa Image Base System to calculate bone-to-implant contact (BIC) and bone area inside the threads. Pearson's correlation analyses were performed to evaluate the correlation between RFA and PTV, BIC and bone area ratio of three different surfaces at 3 and 6 weeks. Results. 1) In all surface treatment methods, the RFA values decreased and the PTV values increased until 6 weeks in comparison to initial values. 2) At 3 weeks, no significant difference was found from bone-to-implant contact ratio and bone area ratio of three different surface treatment methods(P>0.05). However, at 6 weeks, different surface treatment methods showed significantly different bone-toimplant contact ratio and bone area ratio(P<0.05). 3) In the implants with the IBAD on the anodic oxidization, significant difference was found between the 3 weeks and the 6 weeks bone area ratio(P<0.05). 4) Correlation was found between the RFA values and the bone area ratio at 3 and 6 weeks with significant difference(P<0.05). Conclusions. These results indicate that the implants with the IBAD on the anodic oxidization may have a high influence on the initial stability of implant.

• 구강회복응용과학지
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• 제24권4호
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• pp.361-369
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• 2008

본 연구의 목적은 다공성의 티타늄 산화막에 불소를 처리한 결과를 평가하는 것이다. 디스크에 양극산화법을 통하여 다공성의 티타늄산화막표면을 얻은 후 불소를 처리하고 일정시간동안 Hank액에 침전을 시켰다. 양극산화를 통해 일정거칠기의 표면을 얻었으며 SEM과 XRD를 통하여 표면의 형상과 성분을 분석하였다. 생성된 표면은 빠른 표면 활성도를 보였으며, 적절한 거칠기와 좋은 골반응으로 골유착에 기여할 수 있을 것으로 여겨진다.

• Journal of Korean Dental Science
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• 제2권2호
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• pp.12-17
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• 2009

Purpose : To determine whether peri-implant crestal bone loss could be affected by systemic disease, primary ISQ value, implantation method (submerged vs. non-submerged), surface treatment, and bone density Materials and methods : Patients who underwent fixture installation from June 24, 2005 to October 23, 2008 at Seoul National University Bundang Hospital were evaluated. A total of 157 patients (male: 52, female: 85) had 346 fixtures installed. Among them, 49 patients had periapical radiographs taken 1 year after prostheses were first set. A total of 97 fixtures were implanted. In particular, 30 fixtures were installed in patients with systemic diseases such as diabetes mellitus, cardiovascular disease, hypertension, and liver disease. The immediate stability of implants was measured with $Osstell^{tm}$. Implant surface treatment was classified into two groups (RBM, Cellnest (Anodized)), and bone density, into four groups (D1~D4). The bone resorption on the mesial and distal areas of fixtures was measured with periapical radiographs using the paralleling technique, and the mean value was calculated. The length determination program in IMPAX (AGFA, Belgium) was used. Results : At least 332 out of 346 (96%) installed GS II implants were successfully osseointegrated 1 year after prostheses were first set. The mean value of the bone resorption of the installed GS II implants was 0.44mm. The minimum value was 0mm, and the maximum value, 2.85mm. There was a statistically significant difference between the implantation methods (submerged, non-submerged) with regard to the amount of alveolar bone loss 1 year after prostheses were first set (p<0.05). Non-submerged implants showed less crestal bone loss. Note, however, that other variables had no correlation with crestal bone loss (p>0.05). Conclusion : There was a statistically significant difference between the 1-stage method and 2-stage method with regard to the amount of alveolar bone loss 1 year after prostheses were first set. Systemic disease, primary ISQ value, surface treatment, and bone density were not associated with alveolar bone loss. Other variables were assumed to have a correlation with alveolar bone loss.

• 한국광학회지
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• 제19권6호
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• pp.400-407
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• 2008

퓨리에 변환 적외선 분광기(FT-IR)를 이용한 물질의 적외선 분광 복사율 측정 장치를 구축하고 이 장치의 성능을 평가하였다. 본 장치는 기준 흑체, 시료 가열로, 광학계, FT-IR로 구성되어 있으며, 측정 온도 및 파장 영역은 $200^{\circ}C{\sim}500^{\circ}C$와 $3.5{\mu}m{\sim}20{\mu}m$ 이다. 기준 흑체의 유효 복사율은 0.9993 이상으로 거의 1에 가까운 값을 나타내고 있었으며, 흑체의 분광 복사율에 대한 합성 상대 불확도는 0.69% 이하이다. $300^{\circ}C$에서 불투명한 알루미나, 흑연, 양극 처리된 알루미늄 시료의 수직 분광 복사율과, 금속(IMS200)의 표면 거칠기에 따른 복사율을 측정하였다. 금속(IMS200)의 표면 거칠기에 따른 복사율 변화는 거칠기가 증가할수록 증가하였다.

• 한국전기전자재료학회논문지
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• 제23권8호
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• pp.655-659
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• 2010

Nanoporous titanium dioxide ($TiO_2$) is very attractive material for various applications due to the high surface to volume ratio. In this study, we have fabricated nanoporous $TiO_2$ thin films on Si by anodic oxidation. 500-nm-thick titanium (Ti) films were deposited on Si by using electron beam evaporation. Nanoporous structures in the Ti films were obtained by anodic oxidization using ethylene glycol electrolytes containing 0.3 wt% $NH_4F$ and 2 vol% $H_2O$ under an applied bias of 5 V. The diameter of nanopores in the Ti films linearly increased with anodization time and the whole Ti layer could become nanoporous after anodizing for 3 hours, resulting in vertically aligned nanotubes with the length of 200~300 nm and the diameter of 50~80 nm. Upon annealing at $600^{\circ}C$ in air, the anodized Ti films were fully crystallized to $TiO_2$ of rutile and anatase phases. We believe that our method to fabricate nanoporous $TiO_2$ films on Si is promising for applications to thin-film gas sensors and thin-film photovoltaics.

• 한국재료학회지
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• 제20권4호
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• pp.204-209
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• 2010

Recent high efficiency electronic devices have been found to have heat emission problems. As for LEDs, an excessive increase in the device temperature causes a drop of the luminous efficiency and circuit lifetime. Therefore, heat release in the limited space of such electronic parts is very important. This is a study of the possibility of using a coating of carbon materials as a solution for the thermal emission problem of electronic devices. Powdered carbon materials, cokes, carbon blacks, amorphous graphite, and natural flakes were coated with an organic binder on an aluminum sheet and the subsequent thermal emissivity was measured with an FT-IR spectrometer and was found to be in the range of $5{\sim}20\;{\mu}m$ at $50^{\circ}C$. The emissivity of the carbon materials coated on the aluminum sheet was shown to be over 0.8 and varied according to carbon type. The maximum thermal emissivity on the carbon black coated-aluminum surface was shown to be 0.877. The emissivity of the anodized aluminum sheets that were used as heat releasing materials of the electronic parts was reported to be in the range of 0.7~0.8. Therefore, the use of a coating of carbon material can be a potential solution that facillitates heat dissipation for electronic parts.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.241.1-241.1
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• 2011

Numerous possible applications for $ZrO_2$ nanotubes exist such as for catalyst support structures, for sensing or for applications as a solid state electrolyte. Especially, because of a large specific surface area, high efficiency for solid oxide fuel cell (SOFC) application at low temperature can be expected for nanotublar structures in even small size. A zirconium precursor, Tetrakis (ethylmethylamino) zirconium, TEMAZr and $H_2O$ oxidant were used to deposit$ZrO_2$ thin films on an anodized aluminum oxide (AAO) templates having sub-100nm cylindrical pores by atomic layer deposition (ALD) in the temperature range of 150~250$^{\circ}C$. The crystalline structures of as-prepared and post-annealed $ZrO_2$ nanotubes were characterized by x-ray diffraction and high-resolution transmission electron microscopy. The as-prepared samples at $150^{\circ}C$ and $200^{\circ}C$ were showed amorphous, whereas a mixed phase of tetragonal, monoclinic and amorphous polymorph was observed at $250^{\circ}C$. In the bulk, zirconia remains monoclinic phase up to $1,175^{\circ}C$, however, $ZrO_2$ nanotubes were showed tetragonal phase upon post thermal treatments merely at $400^{\circ}C$. This trend may be indicative of high-curvature surfaces of nanotubes and thereby the presence of intrinsic compressive strain. The amount of amorphous structures in the mixed phase as well as as-grown $ZrO_2$ nanotubes were also gradually decreased by subsequent heat treatment.

• 상하수도학회지
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• 제29권1호
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• pp.33-38
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• 2015

In this study, flat-type photocatalytic reaction system is applied to reduce toxic hexavalent chromium (Cr(VI)) to trivalent chromium (Cr(III)) in aqueous solution under UV irradiation. To overcome the limitation of conventional photocatalysis, a novel approach toward photocatalytic system for reduction of hexavalent chromium including nanotubular $TiO_2$ (NTT) on two kinds of titanium substrates (foil and mesh) were established. In addition, modified Ti substrates were prepared by bending treatment to increase reaction efficiency of Cr(VI) in the flat-type photocatalytic reactor. For the fabrication of NTT on Ti substrates, Ti foil and mesh was anodized with mixed electrolytes ($NH_4F-H_2O-C_2H_6O_2$) and then annealed in ambient oxygen. The prepared NTT arrays were uniformly grown on two Ti substrates and surface property measurements were performed through SEM and XRD. Hydraulic retention time(HRT) and substrate type were significantly affected the Cr(VI) reduction. Hence, the photocatalytic Cr(VI) reduction was observed to be highest up to 95% at bended(modified) Ti mesh and lowest HRT. Especially, Ti mesh was more effective as NTT substrate in this research.