• Imaging Science in Dentistry
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• v.38 no.1
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• pp.49-56
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• 2008

Purpose: Diagnostic estimation of destruction and formation of bone has the typical limit according to capacity of x-ray generator and image detector. So the aim of this study was to find out how much it can reproduce the shape and the density of bone in the case of using recently developed dental type of cone beam computed tomography, and which image is applied by new detector and mathematic calculation. Materials and Methods: Cone beam computed tomography (PSR 9000N, Asahi Roentgen Ind. Co., Ltd., Japan) and soft x-ray radiography were executed on dry mandible that was already decalcified during 5 hours, 10 hours, 15 hours, 20 hours, and 25 hours. Estimating and comparing of those came to the following results. Results: The change of inferior border of mandible and anterior border of ramus in the region of cortical bone was observed between first 5 and 10 hours of decalcification. The reproduction of shape and density in the region of cortical bone and cancellous bone can be hardly observed at cone beam computed tomography compared with soft x-ray radiography. The difference of decrease of bone density according to hours of decalcification increase wasn't reproduced at cone beam computed tomography compared with soft x-ray radiography. Conclusion: CBCT images revealed higher spatial resolution. However, contrast resolution in region of low contrast sensitivity is the inferiority of images' property.

• Journal of Environmental Health Sciences
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• v.24 no.3
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• pp.11-17
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• 1998

Chitin is known as biodegradable natural polymer. In spite of various application of chitin derivatives from waste marine sources, commercial use of chitin has been limited due to high resistance to chemicals and the absense of proper solvents. We chitin prepared through the decalcification, bleaching and deproteination from Protunus trituberculatus shells by change of Hackman's method. Also, Microcrystalline chitin made by hydrolysis that was reduce made of resistance solvents used by dilute hydrochloric acid, ultrasonic and hydrogen peroxide. Crosslinked chitin derivatives were preparaed from chitin with crosslink agents(epichlorohydrin, 1,3-dichloropropanol) follwed by crosslinkage at 6C position. The effects of these parameters on chitin dervatives were invastigated by IR, DSC, XRD, BET, PSA and SEM. SEM analysis showed that both chitin and crosslinked chitin had a particle shaped morphology.

• Journal of Food Hygiene and Safety
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• v.14 no.1
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• pp.22-26
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• 1999

The purpose of this experiment was to examine the antimicrobial effect of the natural flavonoid hesperidin on dental caries and alveolar bone resorption in the albinorats. Twenty five day old male rats were fed with the experimental diets for 42 days. At the end of the 42 day experimental period, the molar tooth occlusal surface was examined by a dissecting microscope. The sulcular caries lesions were recorded: the first molar caries incidence was higher than that of the second molar and the third molar. Alvelolar bone resorption was measured on the buccal and lingual aspects of each molars. Three measurements were taken on the first molar (mesialpoint, midpoint, distalpoint). The results of this experiments, showed that hesperidin is effective in reducing dental caries and alveolar bone resorption.

• Proceedings of the KSEEG Conference
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• 2003.04a
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• pp.315-315
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• 2003

Gold mineralization at Kyaukpahto occurs as stockworks/disseminations and locally as breccia zones in silicified sandstones of Lower to Middle Eocene Male Formation of Myanmar. The mineralization is spatially related with NNE -trending fracture zones_probably tensional open fractures caused by the right-lateral Sagaing fault system. Intensive silicification, sericitization, argillic alteration, sulfidation, and decalcification are recognized in the Kyaukpahto mine area. (omitted)

• Journal of Chest Surgery
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• v.55 no.2
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• pp.177-179
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• 2022

Barlow's disease with mitral annular calcification encompassing the subvalvular apparatus, including the valve leaflet and chordae, is extremely rare, and mitral valve repair in such cases is challenging. We report a case of a 60-year-old woman with mitral valve regurgitation that was successfully controlled by resecting the rough zone of P2 and calcifications on the excess leaflet regions and subvalvular apparatus, while retaining the calcification of P3 and implanting artificial chordae and an annuloplasty ring. Mitral valve repair for such cases requires an individualized and compounded surgical strategy for the technique to treat Barlow's disease and manage calcification to control mitral regurgitation.

• The korean journal of orthodontics
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• v.29 no.5 s.76
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• pp.589-597
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• 1999

The purpose of this study was to evaluate the effects of fluoride releasing orthodontic sealants, light-cured (Group L1&L2) and self-cured (Group S1&S2) $FluoroBond^{\circledR}$, on enamel microhardness under artificial carious solution in vitro.112 extracted human premolar teeth were collected for experiments and divided into seven groups. A Tukon microhardness tester equipped with a Knoop diamond indenter was employed to determine microhardness. Tukon 23 program converted the number of microhardness into KHN (Knoop hardness number). The results were as follows: 1. The microhardness of enamel depth of all groups were the least at the depth of $50{\mu}m$ and that of all groups except L2 group, the greatest at the depth of $200{\mu}m$, were the greatest at the depth of $300{\mu}m$. And as the enamel depth of all groups except L2 and S2 group increased, the microhardness value also increased. 2. There was a little preventive effect in enamel decalcification both light-and self-cured orthodontic sealant groups, but had no statistical significance between the groups(p>0.05). 3. Light-cured orthodontic sealant groups had a progressive inhibiting effect in enamel decalcification at the depth of $100{\mu}m,150{\mu}m,\;and\;200{\mu}m$ (p<0.05). 4. Self-cured orthodontic sealant groups had a progressive inhibiting effect in enamel decalcification at the depth of $150{\mu}m$ (p<0.05). 5. There was no difference of the anti-enamel demineralization effect between light- and self-cured orthodontic sealant groups (p>0.05).

• Journal of Periodontal and Implant Science
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• v.26 no.4
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• pp.779-797
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• 1996

The present study investigated the effects of variations in decalcification time of demineralized freeze-dried bone on the osteogenic potential of DFDB. Sixteen 3-wall intrabony defects with 4mm depth were surgically created in the mesial aspect of upper and lower anterior teeth of 4 dogs. Following the flap procedure, three test groups with 4 defects each received either freeze-dried bone graft (Group I), demineralized freeze-dried bone graft decalcified for 12hours (Group II), or demineralized freeze-dried bone graft decalcified for 24hours(Group III). The rest of the four defects received the flap procedure-only as the control group. The healing was histologically analyzed after 14 weeks on the length of connective tissue adhesion, new bone formation and new cementum formation. The results were as follows: 1. The length of connective tissue adhesion showed no statistically significant difference in all groups with $0.62{\pm}0.14mm$ for Control, $0.42{\pm}0.11mm$ for Group I, $0.63{\pm}0.43mm$ for Group II and $0.52{\pm}0.11mm$ for Group III. 2. The new bone formation showed no statistically significant difference in all groups with $3.17{\pm}0.24mm$ for Control. $3.15{\pm}0.56mm$ for Group I. $3.22{\pm}0.36mm$ for Group II, and $3.28{\pm}0.74mm$ for Group III. 3. The new cementum formation showed no statistically significant difference in all groups with $4.19{\pm}0.46mm$ for Control, $3.23{\pm}0.64mm$ for Group I, $4.13{\pm}1.82mm$ for Group II. and $3.13{\pm}0.62mm$ for Group III.

• The korean journal of orthodontics
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• v.33 no.5 s.100
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• pp.381-389
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• 2003

Mutans streptococci is the major causative factor in dental caries. Especially, orthodontic patients with fixed appliance are a risk group for dental caries. Because fixed appliances attached on teeth may change the environment of dental plaque, the enamel decalcification or dental caries around the bracket and band is a major side effect of orthodontic treatmet. The aim of this study was to search plant extracts that have antimicrobial effect on mutans streptococci. Seed-extract of Casia torn were prepared with ethanol and CHMC-2032, the leaf-extracts from Camellia sinensis extract, was obtained extract, 2 type strains and 20 clinical isolates of mutans streptococci isolated from the interface between orthodontic brackets and tooth surfaces in the orthodontic patients were used in this study. The minimal inhibitory concentration of CHMC-2032 was 5mg/ml on the S. mutans KCTC 3065, S. sobrinus KCTC 3088, and 8 clinical isolates of S. sobrinus. However, there was no antibacterial effect of seed-extract of C. tora on mutans streptococci. These data suggest that green tea nay be more effective than the tea Prepared from C tora In the prevention of enamel decalcification or dental caries around brackets.

• The Journal of the Korean dental association
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• v.50 no.7
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• pp.394-406
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• 2012

Objective: The adhesion capabilities of different types of self-ligating brackets were measured with respect to Streptococcus mutans and Streptococcus sobrinus. Methods: Five types of self-ligating brackets (Clippy-C; Mini Clippy; Clarity-SL; Speed; Damon 3) were used for the experiment group and composite resin brackets (Spirit-MB), metal brackets (Victory) and polycrystalline alumina brackets (Clarity) were used for the control group. In order to assess adhesion of bacteria to the brackets, the brackets were cultured for 3, 6 and 24 hours in media containing bacteria and 20% sucrose. Results: There was no statistic difference in adhesion amount of Streptococcus mutans and Streptococcus sobrinus according to the types of brackets. A total adhesion amount according to bracket type was different. An extended incubation time increased adhesion amount. Observation under scanning electron microscope showed that Streptococcus sobrinus adhered more to Clippy-C and Victory rather than to Clarity-SL. Conclusions: Clarity-SL, a self-ligating esthetic bracket was confirmed to show lower bacterial adhesion to cariogenic bacteria, Streptococcus mutans and Streptococcus sobrinus group than other self-ligating brackets or conventional brackets, which suggests that proper use of self-ligating esthetic brackets might even be better in preventing tooth surface decalcification.

• The Journal of the Korean dental association
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• v.54 no.5
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• pp.348-355
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• 2016

Ideal autogenous or allogenic bone graft materials should provide 1) stabilization of blood clot, 2) scaffolds for cellular proliferation and differentiation, 3) release of osteogenic growth factors, 4) appropriate resorption profile for remodeling of new bone. Teeth, especially dentin, mostly contain hydroxyapatite and type I collagen which are similar to bone, and could be valuable graft material. Clinically teeth are used as calcined or demineralized forms. Demineralized form of dentin can be more effective as a graft material. But a conventional decalcification method takes time and long treatment time may give negative effects to various osteogenic proteins in dentin. Author used a new clinical method to prepare autogenous teeth, which could be grafted into the removal defects immediately after extraction using vacuum ultrasonic system. The process could be finished within two hours regardless of the form (powder, chip or block). Teeth were processed to graft materials in block, chip, or powder types immediately after extraction. It took 120 minutes to prepare block types and 40 minutes to prepare powder. Clinical cases did not show any adverse response and the healing was favorable. Rapid preparation of autogenous teeth with the vacuum ultrasonic system could make the immediate one-day extraction and graft possible.