• Restorative Dentistry and Endodontics
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• 제45권4호
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• pp.47.1-47.11
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• 2020

Objectives: The aim of this study was to assess the physicochemical properties, cytotoxicity and penetration into dentinal tubules of ChlorCid^TM Surf (3% sodium hypochlorite [NaOCl] with surfactant) in comparison to ChlorCid^TM (3% NaOCl without surfactant). Materials and Methods: The physicochemical properties evaluated were pH, surface tension, free available chlorine (FAC) and contact angle. Cytotoxicity was evaluated in L929 fibroblasts exposed to the solutions by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and neutral red assays. Assessment of penetration into dentinal tubules was performed by staining single-rooted permanent human teeth with crystal violet (n = 9), which were irrigated with the solutions and analyzed in cervical, middle and apical segments. Data were analyzed by one-way analysis of variance (ANOVA) and Tukey's post-test, 2-way ANOVA and Bonferroni's post-test or t-test (α = 0.05). Results: ChlorCid^TM Surf and ChlorCid^TM FAC values were close to those indicated by the manufacturer. ChlorCid^TM Surf showed lower surface tension and contact angle on dentin, and higher pH than ChlorCid^TM (p < 0.05). The penetration of ChlorCid^TM Surf was higher in cervical and middle segments, compared with ChlorCid^TM (p < 0.05). There was no difference in irrigant cytotoxicity (p > 0.05). Conclusions: ChlorCid^TM Surf showed lower surface tension, lower contact angle on root canal dentin, higher penetration into dentinal tubules and more alkaline pH, compared with ChlorCid^TM. However, both solutions showed similar cytotoxicity and FAC content.

• Restorative Dentistry and Endodontics
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• 제47권2호
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• pp.22.1-22.18
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• 2022

Objectives: This systematic review (register-osf.io/wg7ba) compared the efficacy and safety of rotary and reciprocating kinematics in the removal of filling material from curved root canals. Materials and Methods: Only in vitro studies evaluating both kinematics during retreatment were included. A systematic search (PubMed/MEDLINE, Scopus, and other databases, until January 2021), data extraction, and risk of bias analysis (Joanna Briggs Institute checklist) were performed. Efficacy in filling removal was the primary outcome. Results: The search resulted in 2,795 studies, of which 15 were included. Efficacy was measured in terms of the remaining filling material and the time required for this. Nine studies evaluated filling material removal, of which 7 found no significant differences between rotary and reciprocating kinematics. Regarding the time for filling removal, 5 studies showed no difference between both kinematics, 2 studies showed faster results with rotary systems, and other 2 showed the opposite. No significant differences were found in apical transportation, centering ability, instrument failure, dentin removed and extruded debris. A low risk of bias was observed. Conclusions: This review suggests that the choice of rotary or reciprocating kinematics does not influence the efficacy of filling removal from curved root canals. Further studies are needed to compare the kinematics safety in curved root canals.

• Restorative Dentistry and Endodontics
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• 제47권4호
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• pp.39.1-39.12
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• 2022

Objectives: This study investigated the prevalence and characteristics of external cervical resorption (ECR) regarding sex, age, tooth, stages of progression, and portal of entry, using cone-beam computed tomography (CBCT) scans. Materials and Methods: CBCT scans of 1,313 patients from a Brazilian subpopulation comprising 883 female and 430 male patients (mean age, 55.2 years), acquired using a PreXion 3D CBCT unit, were evaluated. All permanent teeth included in the scans were evaluated for the presence of ECR according to the 3-dimensional classification and the portal of entry. The association between the presence of ECR and the factors studied was assessed using the χ² test. Intra-observer agreement was analyzed with the kappa test (α = 0.05). Results: In total, 6,240 teeth were analyzed, of which 84 (1.35%) were affected by ECR. A significant association was found between the presence of ECR and sex, with a higher prevalence in male patients (p = 0.002). The most frequently affected teeth were the mandibular and maxillary central incisors. The most common height was the mid-third of the root. For the portal of entry, 44% of cases were on the proximal surfaces, 40.5% on the lingual/palatal surface and 15.5% on the buccal surface. Intra-observer agreement was excellent. Conclusions: The prevalence of ECR was 1.35%, with a higher prevalence in male patients and a wide age distribution. The mandibular and maxillary central incisors were the most commonly affected teeth, and cases of ECR most frequently showed a height into the mid-third of the root and proximal entry.

• 대한핵의학회지
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• 제30권3호
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• pp.361-366
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• 1996

본 연구는 $^{99}Mo-^{99m}Tc$ 발생기시스템에서 용출될 수 있는 알루미늄이 $^{99m}Tc$-MDP의 표지효율과 생체내 분포에 어떤 영향을 미치는지를 보기 위한 실험이다. 알루미늄이온 농도 ($0-62.5{\mu}g/ml$)를 증가시킬수록 $^{99m}Tc$-MDP의 표지효율은 급격히 떨어지며 상대적으로 $^{99m}Tc$ pertechnetate와 hydrolyzed reduced $^{99m}Tc$ 부위의 상대적인 양은 증가되었다. $^{99m}Tc$-MDP는 알루미늄 존재하에서도 상당히 안정하였다. 알루미늄에 의해 $^{99m}Tc$-MDP 반응물이 교질을 형성하는지를 보기 위해 $0.22{\mu}m$ syringe filter로 여과한 액은 여과하지 않은 것과 유의한 차이를 나타내지 않았다. 마우스에 대한 생체내 분포실험은 알루미늄에 의해 $^{99m}Tc$-MDP의 표지효율이 떨어지고 $^{99m}Tc$ pertechnetate의 증가로 인해 혈액과 심장의 흡수는 증가하나 간과 뼈의 흡수는 별다른 차이를 나타내지 않았다. 랫트의 골스캔에서는 $5{\mu}g/ml$의 알루미늄농도에서는 영상의 차이가 없으나 $10{\mu}g/ml$ 농도에서는 하복부의 흡수가 높게 나타났다. 이상의 결과는 알루미늄이 $^{99}Mo-^{99m}Tc$ 발생기시스템 칼럼의 용출제한량인 $10{\mu}g/ml$이하에서도 MDP의 표지효율에 상당한 영향을 미칠 수 있다는 것을 보여준다. 따라서$^{99m}Tc$-MDP 골스캔시 연조직에의 흡수가 보이는 경우에도 방사성의약품의 방사화학적 순도에 대한 정도관리가 충분히 이루어 졌다면 $^{99}Mo-^{99m}Tc$ 발생기시스템에서 용출되는 알루미늄에 의한 영향은 배제될 수 있다.

• 대한핵의학회지
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• 제34권4호
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• pp.336-343
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• 2000

목적: $[^{201}Tl]$TICI주사액의 제조과정에서 안정동위원소인 $^{201}Tl$ 및 Cu, Pb의 중금속을 함유할 가능성이 있어 이러한 이물질을 확인하기 위한 방법으로 방사성 물질의 대기오염을 일으키지 않는 폴라로그래피의 분석 조건을 설정하고자 하였다. 대상 및 방법: 원자력병원에서 생산하고 있는 $[^{201}Tl]$-TlCl 주사액에 포함될 수 있는 중금속을 대상으로 하였다. 극미량의 중금속을 측정하기 위한 방법으로 BAS-50W 폴라로그래피를 이용하였고, 여기에 사용된 3 전극계는 작업전극인 DME, 기준전극인 Ag/AgCl 그리고 보조전극인 백금선을 이용하였다. 신속하고 재현성있는 분석을 위한 조건으로 기기의 분석 모드, 각 모드에 적합한 전극, 지지전해질, 석출시간 등의 치적 조건을 설정하였다. 결과: 폴라로그래피의 모드는 OSWSV 방법이 재현성과 감도면에서 가장 우수하였고, 작업전극은 DME와 Au 전극을 비교 실험한 결과 재현성 면에서 DME가 보다 좋은 결과를 보였다. 지지전해질은 염기성인 0.50 M KOH 용액, 산성인 1.0 M $HNO_3$, 용액, 중 성인 pH 7 phosphate 완충용액을 비교 실험하여 pH 7 phosphate 완충용액이 $Tl^+$과 $Cu^{2+}$를 분석하는데 가장 적합함을 확인하였다. 이를 바탕으로 중금속을 측정한 결과 $Tl^+$은 -450 mV, $Cu^{2+}$는 -50 mV에서 각각의 피크가 나타났고, 석출시간을 45초로 하였을 때 $Tl^+$의 경우 y=2.05E-$9{\chi}$+5.66E-9이고 $Cu^{2+}$의 경우는 y=1.23E-$8{\chi}$+1.23E-6의 선형 관계식을 얻었다. 결론: 이 방법에 의한 Tl과 Cu의 검출한계는 약 0.05 ppm이다. 이 방법을 현재 원자력병원에서 생산하고 있는 $[^{201}Tl]$TICl 주사액의 정도관리에 도입하여 중금속을 측정한 결과 약전에서 규정하고 있는 2 ppm 미만임을 확인하였고, 그 결과는 재현성, 정확도, 감도 및 간편성에서 모두 만족할 수 있었다. 이 방법은 $[^{201}Tl]$TlCl 주사액 뿐만 아니라 $^{67}Ga$ 주사액 및 기타 방사성의약품과 중금속 분석에도 응용할 수 있다.

• 대한핵의학회지
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• 제25권2호
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• pp.286-293
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• 1991

$^{123}I$, which is applied for the thyroid and other in vivo kinetic study, has a special role in life sciences. The 159 KeV $\gamma-ray$ from $^{123}I$ is almost ideally appropriate for the current imaging instrumentation. Its decay mode (electron capture) and short half-life (13.3 hr) reduced the burden of radiation dose to the patients, and its chemical property makes it easy to synthesize the labelling compounds. In this experiment, the production of $^{123}I$ via the nuclear reaction $^{124}Te(p,2n)^{123}I$ with 28 MeV protons was sutdied. $TeO_2$ is used as a target material, because it has good physical properties. The target was prepared with $TeO_2$ powder and was molten into a ellipsoidal cavity (a=14 mm, b=10 mm, $270.8mg/cm^2$ thick) of pure platinum. The irradiation was carried out in the external proton beam with incident energies range from 28 MeV to 22 MeV, and current was $30{\mu}A$. The loss of $TeO_2$ target was significantly reduced by using $4\pi-cooling$ system in irradiation. The dry distillation method was adopted for the separation of $^{123}I$ from irradiated target, and when it was kept 5 minutes at $780^{\circ}C$, its result was quantitative. The loss of the target material $(TeO_2)$ was below 0.2% for each production run and $^{123}I$ from the dry distillation apparatus was captured with 0.01 N NaOH in $Na^{123}I$ form, then the pH of the solution was adjusted to $7.5\sim9.0$ with HC1/NaOH. The $Na^{123}I$ solution was passed through $0.2{\mu}m$ membrane filter, and sterilized under high pressure and temperature for 30 minutes. The production of $^{123}I$ is acceptable for clinical application based on the quality of USP XXI.

• BMB Reports
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• 제39권2호
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• pp.216-222
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• 2006

In the present study, we compared six different solubilization buffers and optimized two-dimensional electrophoresis (2-DE) conditions for human lymph node proteins. In addition, we developed a simple protocol for 2-D gel storage. Efficient solubilization was obtained with lysis buffers containing (a) 8M urea, 4% CHAPS (3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate), 40 mM Tris base, 65 mM DTT(dithiothreitol) and 0.2% carrier ampholytes; (b) 5M urea, 2M thiourea, 2% CHAPS, 2% SB 3-10 (N-decyl-N, N-dimethyl-3-ammonio-1-propanesulfonate), 40mM Tris base, 65 mM DTT and 0.2% carrier ampholytes or (c) 7M urea, 2M thiourea, 4% CHAPS, 65 mM DTT and 0.2% carrier ampholytes. The optimal protocol for isoelectric focusing (IEF) was accumulated voltage of 16,500 Vh and 0.6% DTT in the rehydration solution. In the experiments conducted for the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), best results were obtained with a doubled concentration (50 mM Tris, 384 mM glycine, 0.2% SDS) of the SDS electrophoresis buffer in the cathodic reservoir as compared to the concentration in the anodic reservoir (25 mM Tris, 192 mM glycine, 0.1% SDS). Among the five protocols tested for gel storing, success was attained when the gels were stored in plastic bags with 50% glycerol. This is the first report describing the successful solubilization and 2D-electrophoresis of proteins from human lymph node tissue and a 2-D gel storage protocol for easy gel handling before mass spectrometry (MS) analysis.

• Journal of Pharmaceutical Investigation
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• 제27권4호
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• pp.303-311
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• 1997

Proliposomal patch of clenbuterol, ${\beta}_2-agonist$ bronchodilator, was prepared and its feasibility as a novel transdermal drug delivery system was examined. Proliposomal granules containing clenbuterol was prepared by a standard method using sorbitol and lecithin with (Rx 2) or without cholesterol (Rx 1). The porous structure of sorbitol in the proliposomes was maintained allowing tree flowability of the granules. Following contact with water, the granules were converted probably to liposomes almost completely within several minutes. It indicates that proliposomes may be hydrated, when they are applied on the skin under occlusive condition in vivo, by the sweat to form liposomes. Clenbuterol release from Rx 1 and Rx 2 proliposomes to pH 7.4 isotonic phospate buffer (PBS) across cellulose membrane (mol. wt. cut-off of 12000-14000) was retarded significantly compared with that from the mixture of clenbuterol powder and blank proliposomes. Interestingly, proliposomes prepared with lecithin and cholesterol (i.e., Rx 2 proliposomes) showed much more retarded release of clenbuterol than proliposomes prepared only with lecithin (i.e.. Rx 1 proliposomes), indicating that clenbuterol release from proliposomes can be controlled by the addition of cholesterol to the proliposomes. Proliposomal patches were prepared using PVC film as an occlusive backing sheet, two sides adhesive tape (urethane, 1.45 mm thickness) as a reservoir for proliposome granules and Millipore MF-membrane (0.45 mm pore size) as a drug release-controlling membrane. Rx 1 or Rx 2 proliposomes containing 4.6 mg of clenbuterol were loaded into the reservoir of the patch. Clenbuterol release from the patches to pH 7.4 PBS was determined using USP paddle (50 rpm)-over-disc release method. Clenbuterol release from the proliposomal patches was much more retarded even than from a matrix type clenbuterol patch (Boehringer Ingelheim ltd). Being consistent with clenbuterol release from the proliposomal granules, the release from the patches was highly dependent on the presence of cholesterol in the proliposomes : Patches containing Rx 2 proliposomes showed several fold slower drug release than patches containing Rx 1 proliposomes. When the patch containing Rx 1 proliposomes was applied on to the back of a hair-removed rat, clenbuterol concentration in the rat blood was maintained during 6-72 hrs. Transdermal absorption of clenbuterol from the patch was accelerated when the patch was prehydrated with 50 ml of pH 7.4 PBS before topical application. Above results indicate that sustained transdermal delivery of clenbuterol is feasible using proliposomal patches if the cholesterol content and pore size of the release rate-controlling membrane of patches, for example, are appropriately controlled.

• 구강회복응용과학지
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• 제19권4호
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• pp.257-268
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• 2003

The purpose of this study was to assess the loading distributing characteristics of implant prosthesis according to position and direction of load, under vertical and inclined loading using FEA analysis. The finite element model was designed according to standard fixture (4.1mm restorative component x 11.5mm length). The crown for mandibular first molar was made using UCLA abutment. Each three-dimensional finite element model was created with the physical properties of the implant and surrounding bone. This study simulated loads of 200N at the central fossa in a vertical direction (loading condition A), 200N at the outside point of the central fossa with resin filling into screw hole in a vertical direction (loading condition B), 200N at the centric usp in a $15^{\circ}$ inward oblique direction (loading condition C), 200N at the in a $30^{\circ}$ inward oblique direction (loading condition D) or 200N at the centric cusp in a $30^{\circ}$ outward oblique direction (loading condition E) individually. Von Mises stresses were recorded and compared in the supporting bone, fixture, and abutment screw. The following results have been made based on this study: 1. Stresses were concentrated mainly at the ridge crest around implant in both vertical and oblique loading but stresses in the cancellous bone were low in both vertical and oblique loading. 2. Bending moments resulting from non-axial loading of dental implants caused stress concentrations on cortical bone. The magnitude of the stress was greater with the oblique loading than with the vertical loading. 3. An offset of the vertical occlusal force in the buccolingual direction relative to the implant axis gave rise to increased bending of the implant. 4. The relative positions of the resultant line of force from occlusal contact and the center of rotation seems to be more important. 5. The magnitude of the stress in the supporting bone, fixture and abutment screw was greater with the outward oblique loading than with the inward oblique loading and was the greatest under loading at the centric cusp in a $30^{\circ}$ outward oblique direction. Conclusively, this study provides evidence that bending moments resulting from non-axial loading of dental implants caused stress concentrations on cortical bone. But it seems to be more important that how long is the distance from center of rotation of the implant itself to the resultant line of force from occlusal contact(leverage). The goal of improving implants should be to avoid bending of the implant.

• Spatial Information Research
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• 제17권1호
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• pp.131-144
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• 2009

최근 국내의 많은 지방자치단체에서는 정보통신 기술과 도시개발 기술을 융합하여 유비쿼터스 도시(U-City)를 건설하려고 하며, 세계적으로도 많은 도시들이 도시의 경쟁력 강화와 도시민의 삶의 질 향상을 위해 U-City를 개발하기 위해 노력하고 있다. 이러한 시대적 흐름에 따라 각 지방자치단체와 사업 시행자는 최적의 U-City를 구축하기 위하여 많은 방법론을 개발하고 있으며, 기존의 도시개발 방식과 정보화 구축 방식을 연계시키는 등 다양한 개발 절차를 모색하고 있다. 가장 많이 사용되고 있는 방안으로는 도시개발 계획 당시에 개발 될 도시의 정보화 전략계획(ISP)을 수립하는 것이다. 다양한 도시의 환경과 구축기간, 예산, 정보화 기술 등 여러 변수들이 있어 동일한 방법으로 모든 경우에 대한 구축 방안을 수립하기는 어렵다. 따라서 도시 비전과 전략, 서비스와 요소기술의 선정 등에 대한 방안이 필요하게 되었다. 본 논문에서는 U-City를 위한 비전, 전략 수립모형을 만들고 이를 구축할 수 있는 방안으로 하향식 그리고 상향식 접근방법을 제시한다. 또한 U-City를 건설하기 위한 일반적인 추진방법론에 대해서 분석하고 이러한 방법론 안에서 도시 비전 수립을 위하여 두 개의 접근방법을 구성하는 방안에 대하여 논한다.