• Restorative Dentistry and Endodontics
• /
• v.32 no.6
• /
• pp.491-497
• /
• 2007

The purpose of this study was to compare apical sealing ability of continuous wave canal filling technique according to various heat source plugging depths. Eighty one extracted human premolars with straight root were cleaned and shaped to size 35 using .06 taper rotary NiTi file. After cleansing and shaping, the teeth were divided into 5 groups following the heat source probing depths from the apex; 3, 4, 5, 6 and 7 mm. All specimens were filled using E&Q plus with #35/.06 tapered gutta-percha cone. The positive control teeth were not filled. All teeth were coated with nail varnish except the apical 1 mm around the apical foramen. Negative control teeth were completely sealed include the apical foramen. All specimens were immersed in 1% methylene blue solution for 72 hours. Then the specimens were sectioned horizontally at 1, 2 and 3 mm from the root apex. Each sectioned surface was photographed using a digital camera attached to the stereomicroscope at $12.5{\times}2.5$ fold magnification. All points at 1, 2 and 3 mm were summed as final score of one specimen. Statistical analysis of the collected data was performed. Under the condition of this study. there was no significant difference between the heat source plugging depths of 3, 4, 5, 6 and 7 mm in apical sealing ability. All of apical heat source plugging depth from 3 to 7 mm including Buchanan's protocol -from 5 to 7 mm- seems to be acceptable in clinical application.

• Korean journal of applied entomology
• /
• v.44 no.4 s.141
• /
• pp.271-276
• /
• 2005

To investigate feeding behaviour of the greenpeach aphid (Myzus persicae) on several plants, DC electrical penetration graph (EPG) technique was used. We chose 5 plants including pepper, melon, cabbage, radish, and eggplant which were known as major host Plants of this species. This study was focused whether feeding patterns of the aphid were different and which plants would be the most preferable among 5 host plants. The time from initial proboscis contact with a each leaf until the first electrical contact, as a measure of the time taken for the stylet penetration, the time from electrical contact to the first potential drop as a time consumed until intracellular sampling, the number of potential drops per an hour during periods of regular intercellular pathway probing, and the time from electrical contact to tile first phloem specific pattern indicating the time taken to reach and attempt to feed upon the phloem were analysed. As a result, except the number of potential drop, there was no significant differency of feeding patterns among 5 plants. However, the feeding patterns related on host acceptability were observed more frequently from Pepper, radish, and e99r1an1 than melon and cabbage.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.3
• /
• pp.1000-1006
• /
• 2011

The discovery of carbohydrate-based bioactive compounds has recently received considerable interest in the drug development. This paper stresses on the application of 1-methoxy-O-glucoside as the central scaffold, whereas salicylic pharmacophores were introduced with diverse spatial orientations probing into the structural preference of an enzymatic target, i.e. protein tyrosine phosphatase 1B (PTP1B). By employing regioselective protection and deprotection strategy, 2,6-, 3,4-, 4,6- and 2,3-di-O-propynyl 1-methoxy-O-glucosides were previously synthesized and then coupled with azido salicylate via click chemistry in forming the desired bidentate salicylic glucosides with high yields. The inhibitory assay of the obtained triazolyl derivatives leads to the identification of the 2,3-disubstituted salicylic 1-methoxy-O-glucoside as the structurally privileged PTP1B inhibitor among this bidentate compound series with micromole-ranged $IC_{50}$ value and reasonable selectivity over other homologous PTPs tested. In addition, docking simulation was conducted to propose a plausible binding mode of this authorized inhibitor with PTP1B. This research might furnish new insight toward the construction of structurally different bioactive compounds based on the monosaccharide scaffold.

• The Bulletin of The Korean Astronomical Society
• /
• v.38 no.1
• /
• pp.36.2-36.2
• /
• 2013

The SPICA (SPace Infrared Telescope for Cosmology & Astrophysics) project is a next-generation infrared space telescope optimized for mid- and far-infrared observation with a cryogenically cooled 3m-class telescope. The focal plane instruments onboard SPICA will enable us to resolve many astronomical key issues from the formation and evolution of galaxies to the planetary formation. The FPC-S (Focal Plane Camera - Sciecne) is a near-infrared instrument proposed by Korea as an international collaboration. Owing to the capability of both low-resolution imaging spectroscopy and wide-band imaging with a field of view of $5^{\prime}{\times}5^{\prime}$, it has large throughput as well as high sensitivity for diffuse light compared with JWST. In order to strengthen advantages of the FPC-S, we propose the studies of probing population III stars by the measurement of cosmic near-infrared background radiation and the star formation history at high redshift by the discoveries of active star-forming galaxies. In addition to the major scientific targets, to survey large area opens a new parameter space to investigate the deep Universe. The good survey capability in the parallel imaging mode allows us to study the rare, bright objects such as quasars, bright star-forming galaxies in the early Universe as a way to understand the formation of the first objects in the Universe, and ultra-cool brown dwarfs. Observations in the warm mission will give us a unique chance to detect high-z supernovae, ices in young stellar objects (YSOs) even with low mass, the $3.3{\mu}$ feature of shocked circumstance in supernova remnants. Here, we report the current status of SPICA/FPC project and its extragalactic sciences.

• Journal of Periodontal and Implant Science
• /
• v.32 no.1
• /
• pp.41-49
• /
• 2002

The aim of this study was to compare periodontal conditions around mesially tipped molars by a tipping degree. Patients who had been consecutively treated at the Department of Periodontology, Chonbuk National University Hospital from October 1999 to August 2001 were assessed with radiographs taken at their molar regions. Of all molars investigated, 142 molars of 116 patients tipped mesially more than 10 degrees to the line perpendicular to an occlusal plane were selected for the study. The tipped molars were divided into 2 groups with a reference to a tipping degree, i.e., 66 slightly tipped(group 1 : <$30^{\circ}$) and 76 severely tipped molars (group 2 : ${\geq}30^{\circ}$). Probing depth(PD), plaque retention index(PRI) at mesial surfaces of tipped molars and tooth mobility(TM) were recorded at the clinical examination. Tipping degree(TD) and alveolar bony defect(ABD) at the mesial surface of the molars were measured in a radiograph. The results showed that no statistical differences were found between groups in all measured variables. In Pearson correlation analysis performed in the same group, a positive relationship was shown between PRI and PD in the group 1 and, in the group 2, between PRI and PD as well as PRI and ABD(p < 0.01). However, no statistically significant relationship was found between TD and all other variables in both groups. Within limitations of this study, it may be concluded that tipping degree did not seem to influence periodontal conditions, i.e., PD, ABD and TM of mesially tipped molars per se, but plaque presence/absence seemed to mainly affect the periodontal conditions of the tipped molars.

• Journal of Periodontal and Implant Science
• /
• v.26 no.2
• /
• pp.511-521
• /
• 1996

Periodontal pocket is one of the most frequently developed clinical feature on the teeth with periodontal disease. In order to determine the gingival curettage effect of intrapocket irradiation of a pulsed Nd : YAG laser on periodontally involved teeth, bilateral 60 teeth with $4{\sim}6mm$ in probing pocket depth 1 week after supragingival scaling were selected. On half of them the intrapocket irradiation($300{\mu}m$ fiber optic, 1.5W power, for 2min.) of a pulsed-Nd : YAG laser(EL.EN.EN06O, Italy) was applied as the lased group. On the contralateral 30 teeth the subgingival curettage was accomplished by Gracey curettes as the curattage group. The periodontal pocket tissues were surgically excised by the modified Widman flap technique immediately after the intrapocket irradiation or subgingival curettage, subsequently fixed with 10% neutral formalin, sectioned in $4{\sim}6{\mu}m$ thickness, and stained with hematoxylin-eosin. Surface characteristics and incomplete removal of the pocket epithelium were evaluated under light microscope. And the difference between the lased group and the curettage group was statistically analyzed by Chi-square test in Microstat program. The results were as follows ; 1. The plane surface was observed more frequently in the curettage group(73.3%) than in the lased group(23.3%), and the rough surface was observed more frequently in the lased grOoup(63.3%) than in the curettage group(6.7%)(p<0.05). 2. The rate of incomplete removal of the pocket epithelium was relatively high in both the lased group(76.6%) and the curettage group(86.6%), and there was no significant difference between the lased group and the curettage group(p>0.l). The results suggest that the further studies including various power control of laser should be succeeded in order to obtain more favorable results by the intrapocket irradiation of a pulsed Nd:YAG laser than the subgingival curettage with Gracey curettes.

• Journal of Periodontal and Implant Science
• /
• v.26 no.2
• /
• pp.531-541
• /
• 1996

Periodontal disease is characterized by destruction of supporting tissues caused by invasion of plaque bacteria and defense mechanism of host. Many dentists are very interested in laser therapy on various intraoral soft tissue lesions including inflammatory periodontal pocket. In order to determine the therapeutic effect of intrapocket irradiation of a pulsed- Nd : YAG laser on the inflammatory periodontal pockets, bilateral 60 teeth with 4-6mm in probing pocket depth and gingival inflammation were selected and evaluated by sulcus bleeding index(SBI), and plaque index(pI) for baseline record. Intrapocket irradiation($300{\mu}m$ fiber optic, I.5W power, for 2 min.) of a pulsed-Nd : YAG laser(EL.EN.EN060, Italy) was applied on half of them. As the control group, the same procedure except power-off was repeated on the contralateral 30 teeth. At 1-, 2-, 3-, and 4-week after intrapocket manipulation, every tooth was reevaluated by the same clinical indices. And the difference between the lased group and control group was statistically analyzed by paired t-test and Chi-square test in Microstat program. Following results were obtained: 1. Until I-week and 2-week after intrapocket manipulation, SBI was lowered in both lased group and control group, compared to baseline SBI, but from 3-week after, the recovering tendency toward baseline was noted, and at only 2-week after, the number of teeth showing lowered SBI was significantly more in lased group than in control group(p<0.05). 2. PI of both lased group and control group was lowered through whole experimental period from I-week to 4-week after, compared to baseline PI(p<0.05), but there was no significant difference between lased group and control group(p>0.1). The results suggest that intrapocket irradiation of a pulsed-Nd:YAG laser may lead somewhat remission of gingival inflammation, but for more favorable therapeutic result the thorough root planing should be necessarily accompanied with gingival curettage.

• Journal of Periodontal and Implant Science
• /
• v.44 no.3
• /
• pp.126-133
• /
• 2014

Purpose: Smokeless tobacco-based oral-use products like gutka are popular in India. Gutka usage leads to increased periodontal destruction and inflammation; however, the relevant mechanism remains unknown. This study aimed to elucidate the role of gutka in periodontitis by examining its effect on the levels of interleukin (IL) $1{\beta}$ and IL-8 from the gingival crevicular fluid (GCF). Methods: A total of 45 patients were enrolled in this study. Thirty patients with periodontitis (15 gutka chewers [GCP] and 15 nongutka chewers [NGC]) and 15 periodontally healthy controls (HC) were selected. The full-mouth plaque index (PI), gingival index (GI), probing depth (PD), clinical attachment level (CAL), and recession (RC) were recorded. The IL-$1{\beta}$ and IL-8 levels in the GCF of all subjects were assessed through an enzyme-linked immunosorbent assay (Quantikine). Results: The IL-$1{\beta}$ and IL-8 levels were not significantly higher in the GCP group (IL-$1{\beta}$, $369.01{\pm}273.44{\mu}L$; IL-8, $205.97{\pm}196.78{\mu}L$) as compared to those in the NGC group (IL-$1{\beta}$, $195.57{\pm}96.85{\mu}L$; IL-8, $178.61{\pm}149.35{\mu}L$). More gingival RC and loss of attachment was seen among the GCP group (RC: $2.02{\pm}0.31$, P=0.013; CAL: $4.60{\pm}0.56$, P<0.001) than among the NGC group (RC, $1.21{\pm}1.15$; CAL, $3.70{\pm}0.32$); however, PD was deeper among the NGC subjects (P=0.002). PI and GI were significantly higher for the periodontitis group (P<0.001) when compared to the HC, but there was no difference among gutka chewers and non-chewers (P=0.22 and P=0.89). A positive correlation was found between the IL-8 levels and the duration of gutka chewing (r=-0.64, P<0.01). Conclusions: Gutka chewing leads to increased gingival RC and clinical loss of attachment. There was no effect seen in the proinflammatory cytokine levels in the GCF of gutka users.

• Journal of Periodontal and Implant Science
• /
• v.38 no.1
• /
• pp.97-102
• /
• 2008

Purpose: Periodontal intrabony defects have great deal of importance since they contribute to the development of periodontal disease. Current treatment regimens for intrabony defects involve grafting of numerous bony materials, GTR using biocompatible barriers, and biomodification of root surface that will encourage the attachment of connective tissue. Xenograft using deproteinized bovine bone particles seems to be very convenient to adjust because it doesn't require any donor sites or imply the danger of cross infections. These particles are similar to human cancellous bone in structure and turned out to be effective in bone regeneration in vivo. We here represent the effectiveness of grafting deproteinized bovine bone particles in intrabony defect and furcation involvements that have various numbers of bony walls. Materials and methods: Open flap debridement was done to remove all root accretions and granulation tissue from the defects within persisting intrabony lesions demonstrating attachment loss of over 6mm even 3 months after nonsurgical periodontal therapy have been completed. Deproteinized bovine bone particles($BBP^{(R)}$, Oscotec, Seoul) was grafted in intrabony defects to encourage bone regeneration. Patients were instructed of mouthrinses with chlorohexidine-digluconate twice a day and to take antibiotics 2-3 times a day for 2 weeks. They were check-up regularly for oral hygiene performance and further development of disease. Probing depth, level of attachment and mobility were measured at baseline and 6 months after the surgery. The radiographic evidence of bone regenerations were also monitored at least for 6 months. Conclusion: In most cases, radio-opacities increased after 6 months. 2- and 3-wall defects showed greater improvements in pocket depth reduction when compared to 1-wall defects. Class I & II furcation involvements in mandibular molars demonstrated the similar results with acceptable pocket depth both horizontally and vertically comparable to other intrabony defects. Exact amount of bone gain could not be measured as the re-entry procedure has not been available. With in the limited data based on our clinical parameter to measure pocket depth reduction following $BBP^{(R)}$ grafts, it was comparable to the results observed following other regeneration techniques such as GTR.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.29 no.4
• /
• pp.418-425
• /
• 2013

This case report describes about recurrent herpetic stomatitis mimicking post-root resection complication. A 49 year-old male patient was diagnosed vertical root fracture of the mesiobuccal root of his left maxillary first molar (#26). The mesiobuccal root was resected following root canal treatment of the same tooth. 19 months later, the patient presented with pain on left hard palate after a barbecue party. Intra oral examination revealed a gum boil-like blister at the hard palate corresponding to the apex of the palatal root of #26. On clinical examination, there was bleeding on probing and the periodontal pocket depth was measured less than 5 mm with no tooth mobility. On a periapical radiograph, periodontal ligament space widening was observed. Tracing the sinus tract with gutta percha cone was attempted, however, it was impossible. Extending the field of vision, small multiple round ulcerations were observed at the palate front which caused pain to the patient. Therefore, the pain was considered a non odontogenic and the patient was referred to the department of oral medicine. The patient was diagnosed recurrent herpetic stomatitis and after 3 days of antiviral medication, the pain and ulceration were subsided.