• KSBB Journal
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• v.8 no.2
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• pp.126-132
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• 1993

The objective of this study was to develop an artificial dentin for easy handle and accurate observation of the mechanism on dental caries and to screen biologically active materials from the extracts of traditional plants and fruits for prevention of early dental cares. In order to produce disc PAHA (artificial dentin), the powdered hydroxylapatite was immobilized in a 20% polyacrylamide gel. The characteristics of disc PAHA was very similar to the surface, figure and lattice of human enamel. After decalcification in 0.1M citric acid based on observation with SEM. The critical point of decalcification of disc PAHA by acids was found to be pH 5.0-5.5, which was hi agreement with human enamel. The degree of decalcification from disc PAHA in 0.1M citric acid solution was sixfold higher than that of human enamel. This result suggested that disc PAHA would be useful as a substitute of human enamel for in vitro experiment. The extracts of garlic and Flower Apple A, B seemed to inhibit growth of S. mutans. Especially, when the 300$\mu\ell$ of its extracts added to the medium to incubate S. mutans, F. apple B showed strongly an inhibitory effect in both the growth of S. mutans and the synthesis of insoluble glucan.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2003.05a
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• pp.579-587
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• 2003

A lot of VOCs that is noxious ate exhausted at drying process of enamel coating device. This VOC gas can be incinerated perfectly through catalytic combustion, and heat that is occurred in incineration process ran be again used in drying process. By using VU catalytic combustion technology, in this study, we developed a enamel coating machine that have an excellent environment improvement and energy saying effect. As basic research for this development characteristics ana performance of catalytic combustion for VOC gas was evaluated and numerical analysis for drying oven was calculated. According to the result, VOCs combustion characteristics of metal form catalysis was excellent in high temperature, and it was seen that enamel coating machine should be designed as a precious controllable structure of recirculating supply rate and suction rate.

• Journal of the korean academy of Pediatric Dentistry
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• v.3 no.1
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• pp.33-39
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• 1976

The present in vitro study was undertaken to evaluate the initial marginal sealing ability of the sealant known as Nuva-Seal to seal cavity margins when used in conjunction with Adaptic and Nuva-Fil restorative materials. The results were as follows; 1. Where each Adaptic and Nuva-Fil restorative material was filled, showed the greatest degree of marginal leakage. 2. Where Adaptic and Nuva-Fil restorative materials were filled after acid etched surrrounding enamel surface adjoining the cavity margins, showed some degree of marginal leakage. 3. Where the Nuva-Seal was applied after acid etching a) to the cavity walls and the peripheral enamel surface adjoining the cavity margins, b) only to the surrounding enamel surface adjoining the cavity margins, and c) over the restorations and the peripheral enamel surface, showed complete absence of marginal leakage of Adaptic and Nuva-Fil restorative materials. 4. Where the Nuva-Seal was applied with the same methods as above, and restorations were placed on thermal stress also showed complete absence of marginal leakage of Adaptic and Nuva-Fil restorative materials.

• Journal of the korean academy of Pediatric Dentistry
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• v.23 no.2
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• pp.306-326
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• 1996

The purpose of this study was to compare the enamel fluoride uptake and anticariogenic effect following topical application with different physical form of fluoride and application time. The results can be summarized as follows: 1. While the 4-minute applicaton increased the enamel fluoride uptake significantly than 1-minute application regardless of physical form of applied topical fluoride agents, no siginificant difference could be found between foam and gel type when applied for the identical period of time. 2. The application time or the physical form of topical agents had no singificant influence on the reduction of caries lesion. 3. Based upon the above-mentioned results of this study, it cannot be concluded that the amount of enamel fluoride uptake has an absolute impact on the change of lesion depth. Therefore, the clinical application of 1-minute topical fluoride application which appears to have a similar anticariogenic efficacy to 4-minute fluoride application may be encouraged.

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.3
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• pp.513-524
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• 1998

The purpose of this study was to compare the staining ratio on the enamel surface following the use of chlorhexidine mouthwash and the chlorhexidine varnish application. Labial and lingual surfaces of maxillary and mandibular incisors of adults were selected to evaluate the staining ratio. The control group was consisted of 8 individuals, the experimental group 1 and 2 were consisted of 50 each. Prophylaxis with pumice was performed to remove the stain already established on the enamel surface of all groups. The group 1 was asked to use chlorhexidine mouthwash(Hexadent, chlorhexidine gluconate 1ml/100ml) for a minute twice a day. The chlorhexidine $varnish^{(R)}$($Chlorzoin^{(R)}$, consisted of solution 1(10% chlorhexidine acetate) and solution 2(polyurethane sealant)) was applied on the enamel surfaces of the group 2. After 4 weeks of experiment, intraoral photogragh of tooth surfaces were taken in order to record the stained area on the enamel of the control and the experimental groups. Outline of teeth and the stained area in the photographs was traced on the OHP film. Scanner and computer processor were used to calculate stained surface ratio.

• The korean journal of orthodontics
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• v.43 no.1
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• pp.29-34
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• 2013

Objective: To examine the prophylactic potential of 3 orthodontic bonding adhesives: Fuji Ortho SC, Illuminate, and Resilience. Methods: Thirty-six Wistar Wag rats were randomly divided into 4 groups consisting of 9 rats each. One of the groups received no treatment and was used as a control. In the other groups, individual bands coated with one of the 3 adhesives were cemented to the lower incisors. Enamel samples were obtained after 6 and 12 weeks and analyzed using scanning electron microscopy in combination with energy dispersive spectrometry. Results: Six weeks after band cementation, no fluoride was found in the enamel of the lower incisors. After 12 weeks, there was no fluoride in the enamel of teeth coated with the Resilience composite. However, in the case of the Illuminate composite and the resin-modified glass ionomer Fuji Ortho SC cement, the depth of fluoride penetration reached $2{\mu}m$ and $4.8-5.7{\mu}m$, respectively. Conclusions: Fluoride ions from orthodontic adhesives can be incorporated into the surface layer of the enamel. Orthodontists may apply orthodontic adhesives, such as the Fuji Ortho SC, to reduce the occurrence of caries during orthodontic treatment with fixed appliances.

• Bulletin of the Korean Chemical Society
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• v.30 no.4
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• pp.887-890
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• 2009

Hydroxyapatite (HAp)-based materials have attracted considerable attention on account of their excellent stability and recrystallization. Nanoscale HAp powders with a mean particle size of 200 nm were used to regenerate the enamel layers of damaged teeth. An artificially scratched tooth was immersed in a nanoscale HAp powder suspension in d.i. water (HAp of 70 wt%) at 37 ${^{\circ}C}$ for a period of 1~3 months. SEM and AFM showed that the scratched surface was ultimately inlaid with HAp after three months and the roughness increased from 2.80 to 5.51. Moreover, the hardness of the neo-generated HAp layer on the crown was similar to that of the innate layer. $Ca^{2+}$ and ${PO_4}^{3-}$ ions from the HAp powders dissolved in d.i. water were precipitated on the tooth to produce cemented pasteson the enamel surface due to its high recrystallizing characteristics, resulting in a hard neo-regenerated HAp layer on the enamel layer. This nanoscale HAp powder solution might be used to heal decayed teeth as well as to develop tooth whitening appliances.

• Restorative Dentistry and Endodontics
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• v.43 no.2
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• pp.20.1-20.9
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• 2018

Objectives: The aim of this in vitro study was to evaluate the bond strength of 2 universal adhesives used in different application modes to bleached enamel. Materials and Methods: Extracted 160 sound human incisors were used for the study. Teeth were divided into 4 treatment groups: No treatment, 35% hydrogen peroxide, 16% carbamid peroxide, 7.5% carbamid peroxide. After bleaching treatments, groups were divided into subgroups according to the adhesive systems used and application modes (n = 10): 1) Single Bond Universal, etch and rinse mode; 2) Single Bond Universal, self-etch mode; 3) Gluma Universal, etch and rinse mode; 4) Gluma Universal, self-etch mode. After adhesive procedures nanohybrid composite resin cylinders were bonded to the enamel surfaces. All specimens were subjected to shear bond strength (SBS) test after thermocycling. Data were analyzed using a 3-way analysis of variance (ANOVA) and Tukey post hoc test. Results: No significant difference were found among bleaching groups (35% hydrogen peroxide, 16% carbamid peroxide, 7.5% carbamid peroxide, and no treatment groups) in the mean SBS values. There was also no difference in SBS values between Single Bond Universal and Gluma Universal at same application modes, whereas self-etch mode showed significantly lower SBS values than etch and rinse mode (p < 0.05). Conclusions: The bonding performance of the universal adhesives was enhanced with the etch and rinse mode application to bleached enamel and non-bleached enamel.

• Restorative Dentistry and Endodontics
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• v.17 no.1
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• pp.206-213
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• 1992

The aim of this study was to compare the accuracy of radiographic diagnosis of secondary carious lesions adjacent to composite filling materials with different radiopacity. The level of radiopacity that is most compatible with the radiographic diagnosis of secondary caries was studied in a two part experiment. In the first part, the radiopacity of 6 posterior composites CBP, CF, HM, LF, PQ, P50), enamel and dentin were measured by desitometer and 6 posterior composites divided into 3 groups based on their level of radiopacity compared with enamel and dentin. In the seocnd part, class II composite fillings with or without secondary caries were made in extracted premolar and radiographs of the teeth were examined by 10 dentists to diagnose simulated carious lesion. The following results were obtained: 1. The radiopacity of 6 posterior composites varied between 1.76(PQ) and 6.78(P50)mm Al equivalent. 2. For 4 composites the radiopacity exeeded that of an equal thickness of enamel, and for two the radiopacity was lower than that of dentin. 3. The detection of secondary caries was facillitated when the radiopacity of a composite resin was similar to or slightly greater than that of enamel.

• The korean journal of orthodontics
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• v.22 no.2 s.37
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• pp.449-474
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• 1992

The purpose of this study was to evaluate the in vitro shear bond strengths to enamel and the failure sites of three ceramic brackets and one metal bracket in combination with light cured orthodontic adhesive. The brackets were divided into four groups. Each ceramic bracket group had different bonding mechanisms with adhesive. Group A; metal bracket with foil-mesh base (control group) Group B; ceramic bracket with micromechanical retention Group C; ceramic bracket with chemical bonding Group D; ceramic bracket with mechanical retention and chemical bonding. Forty extracted human lower first premolars were prepared for bonding and 10 brackets for each group were bonded to prepared enamel surfaces with $Transbond^{\circledR}$ light cured ortho dontic adhesive. Twenty four hours after bonding, the Instron universal testing machine was used to test the shear bond strength of brackets to enamel. After debonding, brackets and enamel surfaces were examined under stereoscopic microscope to determine the failure sites, Statistical analysis of the data was carried out with ANOVA test and $Scheff\acute{e}$ test using SPSS PC+. The results were as follows. 1 . There were statistically significant differences in mean shear bond strengths of three ceramic bracket groups (p < 0.05). Shear bond strengths of group C and D were significantly higher than that of group B and shear bond strength of group C was significantly higher than that of group D. 2. Group C and D both had significantly higher shear bond strengths than metal bracket (group A), but there were no significant differences in shear bond strengths between group A and B (p < 0.05). 3. The failure sites of four bracket groups were also different. Group C and D failed primarily at enamel-adhesive interface, but group A and B failed primarily at bracket base-adhesive interface. 4. Among all ceramic bracket groups, group B was very similar to metal bracket in the aspect of shear bond strength and failure site.