• The Journal of the Korean dental association
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• v.12 no.5
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• pp.327-332
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• 1974

The effects of enamel solubility by the varying concentration of fluoride and phosphate as well as pH of the acid fluoride-phosphate solutions were tested and compared with th 7% stannous fluoride solution. The smooth surface of the sound permanent 1st premolars were demineralized by the Buttner's method. And the phosphorus extracted from the 1st premolars were analyzed by the Fiske and Subbarow's method. Enamel smooth surfaces treated with the acid fluoride-phosphate solution and the 8% stannous fluoride solution were obserbed electron-microscopically by the Filmy Replica method. The results of this study were summarized as follows: !. The least enamel dissolution rate was observed at the acid fluoride-phosphate solution contained 1.25% fluorine, 0.5% phosphate, and pH 4. 2. The anti-cariogenic effects comparison between the acid fluoride-phosphate solution and 8% stannous fluoride, the former was higher.

• Proceedings of the KACD Conference
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• 2001.11a
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• pp.567.2-567
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• 2001

The purpose of this study was to evaluate the shape, the composition of Calcium Hydroxide Points (CH Point) and to determine the pH level in water. The shape of CH Point was measured by using a profile projector. The composition of the CH Point was analyzed by the X-ray diffraction and the EPMA. ＃60 CH Point was stored in 10ml of demineralized water that was replaced every day or not replaced for 7 days period. The pH levels of the water were measured by using an ion electrode with an ion meter every day.(omitted)

• Journal of the korean academy of Pediatric Dentistry
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• v.23 no.4
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• pp.931-936
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• 1996

Many kinds of soluble calcium salts such as calcium lactate are known to reduce the enamel demineralization. In this study, calcium lactate was tested for its effect on the demineralization process of hydroxyapatite. Synthetic hydroxyapatites were used as a standardized material instead of human enamel which is rarely heterogenous. And, for the purpose of hydroxyapatite demineralization, lactic acid was used. By comparing the weight of hydroxyapatite pre-demineralization and post-demineralization, it was possible to examine the effect of calcium lactate on demineralization. The weight of demineralized hydroxyapatite was reduced by about 46% and 59% with 20mM and 40mM calcium lactate, respectively. In conclusion, low concentrations of calcium lactate showed an inhibitory effect on the demineralization of synthetic hydroxyapatite.

• Applied Microscopy
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• v.28 no.4
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• pp.551-561
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• 1998

The autometallographic method was used to demonstrate the localization of mercury deposits in spleen of mouse. The mercury deposits were identified with the light and electron mocroscope. Mice were treated with methylmercuric chloride in the drinking water (demineralized water) for 40 days. Control and mercury treated groups showed no significant differences in mean body weight and spleen weight per one mouse. Mercury grains were appeared in the germinal center of white pulp consist of a preponderancing lymphocytes, not in red pulp and capsule. At the ultrastructural level, mercury deposits were restricted to lysosomes of macrophage and lymphocyte. Specially, volume in lysosomes of the macrophage was increased. These results suggest that mercury localization in lysosomes is associated with the change of immune activity.

• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.1
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• pp.44-50
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• 2016

The purpose of this study was to compare and evaluate the remineralization effect of three types of fluoride varnishes on demineralized enamel of primary teeth. 40 primary teeth were decalcified by soaking them in artificial acidic solution and stored at $37^{\circ}C$ for 7 days. Then 3 varnishes - Cavity shield$^{TM}$, V varnish$^{TM}$ and MI varnish$^{TM}$ were applied respectively one time a week, for 3 weeks on the demineralized enamel surface. For the first week, MI varnish$^{TM}$ showed the highest microhardness value, V varnish$^{TM}$ was in second position, and Cavity shield$^{TM}$ showed the lowest microhardness value. However, there was no significant difference among the three groups(p > 0.05). For the second week, V varnish$^{TM}$ showed the highest microhardness value, and MI varnish$^{TM}$ came next in second position noting no significant difference (p > 0.05). Cavity shield$^{TM}$ was significantly lower than the other groups (p < 0.05). For the third week, V varnish$^{TM}$ showed the highest microhardness value, noting a significant difference from the other groups (p < 0.05). MI varnish$^{TM}$ came next, while Cavity shield$^{TM}$ showed the lowest microhardness value. However, there was no significant difference between MI varnish$^{TM}$ and Cavity shield$^{TM}$ (p > 0.05). The increase in the microhardness of groups V varnish$^{TM}$ and MI varnish$^{TM}$ were higher than that of group Cavity shield$^{TM}$ (p < 0.05), while no significant difference was noted between groups V varnish$^{TM}$ and MI varnish$^{TM}$ (p > 0.05).

• Polymer(Korea)
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• v.36 no.6
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• pp.768-775
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• 2012

Alginate, obtained from the seaweeds, is a widely used biomaterial for cell transplantation, since its positive effect on viability of capsulized cells and its easier encapsulation capability of living cells. Demineralized bone powder (DBP), derived from the natural bone tissue, is widely applied for clinical trials for its low rate of reaction and antigenicity. A chondrocyte was seeded into an alginate with DBP of different contents, and a microcapsule was produced. The adhesion and proliferation of cells was observed through the MTT analysis, and the PCR was applied to estimate the content of the glycosaminoglycan (sGAG) and collagen, and confirm the specific genetic pattern of the chondrocytes. Also, the alginate microcapsule where the chondrocyte is seeded was extracted after transplantation under the skin of a nude mouse, and was immunochemically stained. The experimental result confirmed that the alginate microcapsule containing 1% of DBP not only showed the highest proliferation of cell but had a positive effect of chondrocytes by the interaction between the alginates and the growth factor in DBP. It can be expected that the microcapsule with application of the alginates and DBP might be an appropriate scaffold for tissue engineering.

• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.141-161
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• 1998

The depth and patterns of demineralization according to the difference in concentration and application time of phosphoric acid were observed through the transmission electron microscope, and shear bond strengths to the acid -conditioned dentin were then measured and compared with the TEM results. To investigate the influence of polymer addition into the phosphoric acid and the effect of difference in concentration and application time of the acid, the specimens were randomly divided into 9 groups. Among the specimens, the exposed dentin surfaces were acid-conditioned with 10% polymer-thickened phosphoric acid(All Bond 2, Bisco, U.S.A.) and aqueous 10%, 20%, 30%, 40% phosphoric acid for 20 seconds, The rest of the specimens were acid-conditioned with 10% phosphoric acid for 15s, 30s, 60s, 120s respectively. The specimens were immersed in 4% glutaraldehyde in 0.1M sodium cacodylate buffer and postfixed with 1 % osmium tetroxide without decalcification and then observed under a JEOL Transmission Electron Microscope(JEM 1200 EX II, Japan). After the specimens were acid-conditioned as the above, primer and adhesive resin were applied to blot-dried dentin and shear bond strengths were then measured and analysed. The results were as follows : 1. The intertubular demineralization depth of 4.0-$5.0{\mu}m$ in 10% polymer-thickened phosphoric acid gels was similar or slightly deeper than that of 4.0-$4.5{\mu}m$ in aqueous 10% phosphoric acid solution. 2. The intertubular demineralization depth of aqueous 20%, 30% and 40% phosphoric acid solution was 6.5-$7.0{\mu}m$, 6.5-$7.5{\mu}m$ and 9.0-$15.0{\mu}m$ respectively. It showed that the depth of dentin demineralization is partly related to the concentration of phosphoric acid solution. 3. The intertubular demineralization depth of aqueous 10% phosphoric acid solution in application time for 15s, 30s, 60s and 120s was 2.5-$3.0{\mu}m$, 4.0-$6.0{\mu}m$, 6.5-$7.0{\mu}m$ and 8.5-$14.0{\mu}m$ respectively. It showed that the depth of dentin demineralization is directly related to the application time of phosphoric acid solution. 4. The partially demineralized dentin layer between demineralized collagen layer and unaffected dentin was showed to a width of 0.5-$1.0{\mu}m$ in lower concentration groups treated with aqueous 10% phosphoric acid for 20s, 60s, 120s and 20% phosphoric acid for 20s. 5. The demineralization effect at the border of intertubular-peritubular junction was less evident than that in the peritubular and intertubular dentin. The collagen fibers in the intertubular dentin had a random orientation, whereas those that lined the tubules were circumferentially aligned. The cross-linkage of dentinal collagen in demineralized collagen layer was clearly seen. 6. A statistically significant difference of bond strengths according to the difference in phosphoric acid concentration did not exist among the groups treated with 10%, 20%, 30% and 40% acid solution (P>0.05). However, bond strengths to the treated dentin with 10% phosphoric acid solution for 30s were significantly higher than that for 120s (P<0.05).

• Applied Microscopy
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• v.16 no.2
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• pp.1-13
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• 1986

The purpose of this study was to investigate the morphology and intercellular junctions of the odontoblast of dental pulp in the rat incisor by means of the freeze fracture electron microscopy. Twenty male Sprague-Dawley rats weighing $150{\sim}200g$ were used. After being anesthetized by an intraperitoneal injection of 0.5 ml sodium pentobarbital per kg in body weight(60 mg/ml) the animals were perfused with 2.5% glutaraldehyde-2% paraformaldehyde fixative in 0.1 M cacodylate buffer, pH 7.2 through the ascending aorta for one hour. The incisors were carefully extracted from the jaws and demineralized by suspending them in 0.1 M EDTA in 3% glutaraldehyde (pH 7.2) for two weeks. After demineralization, the specimens were obtained from the portion divided into five equal parts. For freeze-fracture replication, demineralized tissues were infiltrated for several hours with 10%, 25% glycerol in 0.1M cacodylate buffer as a cryoprotectant and then frozen in liquid Freon 22 and stored in liquid nitrogen. Fracturing and replication were done in Balzers BAF 400D high-vacuum freeze-fracture apparatus at $-120^{\circ}C$ under routine $5X10^{-7}$ Torr vacuum. The tissue was immediately replicated with platinum unidirectionally at $45^{\circ}$ angle and reinforced with carbon at $90^{\circ}$ angle unidirectionally or by using a rotary stage. The replication process was monitored by a quartz-crystal device. The replicas were immersed in 100% methanol overnight. The tissue was then digested from the replica by clorox (laundry bleach), placed into 5% EDTA, and washed repeatedly with distilled water. The replicas were picked up on 0.3% formvar-coated 75 mesh grids and examined in the JEOL 100B electron microscope. The results were as follows; 1. Both in thin sections and freeze-fracture replicas, three types of intercellular junctions were recognizable in the plasma membrane of odontoblast: gap junction, tight junction and desmosome-like junction. 2. The nuclear pores were evenly distributed over the nuclear envelope. The pore complex formed a ring about 70 nm in diameter. 3. Gap junctions were found between odontoblasts as well as odontoblasts and neighbouring pulp cells (fibroblast, subodontoblastic cell process, nerve-like fibre). Gap junctions, which were round, ellipsoid and pear-shaped and 600 nm in diameter, were observed in the odontoblast. 4. Numerous round and ellipsoid gap junctions could be frequently seen on the plasma membranes in cell body and apical part of the odontoblasts. On the P face, the junctions were recognized as a cluster of closely packed particles, measuring about 9 nm in diameter, and on the E face, the junctions were recognized as a shallow grooves.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.3
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• pp.198-206
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• 2009

Purpose: The aims of this study were to assess the in vitro co-culturing pattern of isolated skin-derived precursor cells (SKPs) with a mixed demineralized bone (DMB) and fibrin glue scaffold and to evaluate in vivo osteogenesis after transplantation of autogenous SKPs with a these mixed scaffold in the animal's mandibular defects. Materials and Methods: We isolated SKPs from the ears of adult 4 miniature pigs. The isolated SKPs were co-cultured with a mixed DMB and fibrin glue scaffold in a non-osteogenic medium for 1, 2, and 4 weeks. Histological characteristics of in vitro co-cultured cells and scaffold were evaluated. $1{\times}10^7\;cells/100\;{\mu}l$ of autogenous porcine SKPs were grafted into the mandibular defects with a DMB and fibrin glue scaffold. In the control sites, only a scaffold was grafted, without SKPs. After two animals each were euthanized at 2 and 4 weeks after grafting, the in vivo osteogenesis was evaluated with histolomorphometric and osteocalcin immunohistochemical studies. Results: Homogeneously shaped skin-derived cells were isolated from porcine ear skin after 3 or 4 weeks of primary culture. In vitro osteogenic differentiation of SKPs was observed after co-culturing with a DMB and fibrin glue scaffold in a non-osteogenic medium. Von Kossa-positive bone minerals were also noted in the co-cultured medium at 4 weeks. As the culture time progressed, the number of observable cells increased. Trabecular new bone formation and osteocalcin expression were more pronounced in the SKP-grafted group compared to the control group. Conclusion: These findings suggest that autogenous SKP grafting with a DMB and fibrin glue scaffold can serve as a useful alternative to bone grafting technique.

• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.4
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• pp.443-451
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• 2016

Subjects of this study were : $FluoroDose^{(R)}$ (FD, Centrix Inc., USA), $Enamelast^{TM}$ (EL, Ultradent Product Inc., USA), $Clinpro^{TM}$ white varnish (CW, 3M ESPE, USA), $CavityShield^{TM}$ (CS, 3M ESPE, USA), V $varnish^{TM}$ (VV, Vericom, Korea), MI $varnish^{TM}$ (MI, GC, Japan). The amount of fluoride ion release was measured eight times during 168 hours to see change in accumulation with the course of time using a measuring instrument. And the remineralization rate was measured with Quantitative Light-induced Fluorescence (QLF). V $varnish^{TM}$ group and MI $varnish^{TM}$ group showed high remineralization rates with statistically significance while $CavityShield^{TM}$ group was the lowest rate of remineralization (p < 0.05). After that, several chosen samples were scanned through electron microscope (SEM). Demineralized enamel was observed as the number of enamel crystal was very small; enamel rods and crystals were highly protruding. Remineralized groups with fluoride varnishes show the decreasing tendency of the surface roughness compared to the demineralized enamel.