• Journal of dental hygiene science
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• v.14 no.4
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• pp.589-596
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• 2014

This study was designed to investigate the using status and awareness of pit and fissure sealant, and how it affects on secondary caries when performed on above of initial caries. After classifying 446 occlusal surface into four groups, performed pit and fissure sealant, induced artificial caries, used DIAGNOdent (Kavo) to measure degree of secondary caries. Also, distributed a questionnaire on dental clinic in metropolitan area to find out using status and awareness of pit and fissure sealant, the following results were obtained. 1) On inspection and percussion, Group 4 corresponding to the enamel caries showed the highest secondary caries after sealant and was statistically significant difference in the order of initial group, stained group, sound group (p<0.05). 2) Inspection showed the highest percentage on tooth fissure caries diagnostic methods before sealant. 3) 56.6% didn't know about DIAGNOdent, 91.6% didn't have it. 4) In clinically, the most cause of secondary caries after sealant was a broken sealant, making caries on the downward. Based on the results of above study, degree of caries under sealant could affect on secondary caries, needs publicity about the use and necessity of objective fluorescence device.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.3
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• pp.381-390
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• 2004

The purpose of this in vitro study was to investigate the effects of Nd:YAG laser irradiation and fluorides on acid drink demineralized enamel. The materials were 30 freshly extracted permanent premolars with intact smooth enamel surfaces. They were demineralized with Coca-cola at $37^{\circ}C$ for 12hours and then irradiated by Nd:YAG laser with 6W power, $50mJ/cm^2$ energy density, and 20Hz pulse repetition. After laser irradiation, teeth were treated by three kinds of fluorides; (1)0.05% NaF fluoride solution (2)1.23% APF gel and (3)0.1%F fluoride varnish, microhardness(VHN) and Diagnodent scores were measured and the surfaces of each treated specimens were also observed with SEM under 1500 magnification. The results were as follows: 1. In the change of microhardness(VHN), it decreased to 34.68% from the initial micrhardness, increased to 78.37% after laser irradiation and increased to 82.62% after fluoride treatment, there were significant differences except when it was irradiated and treated with fluoride(P<0.05). 2. In the change of Diagnodent scores, it was decreased to 28.08% from the initial scores after demineralization, and then increased to 59.81% after laser irradiation, and increased to 82.17% after fluoride treatment. Scores were different significantly between the scores of initial, demineralization, laser irradiation and fluoride treatment(P<0.05). All the scores were not different significantly between fluoride types. 3. SEM observation showed that the lased enamel surfaces after demineralization were thermally degenerated and showed molten lava-like appearance and crater with cracks and many microholes.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.2
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• pp.262-268
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• 2006

The purpose of this in vitro study was to evaluate the remineralizing effects of Nd : YAG laser irradiation and fluorides application on primary tooth enamel eroded by acidic drink. The materials were 30 sound primary teeth with intact smooth enamel surfaces. They were demineralized with Coca-cola at $37^{\circ}C$ for 12 hours and then irradiated by Nd: YAG laser with 6W power, $50mJ/cm^2$ energy density. and 20Hz pulse repetition. After laser irradiation, teeth were treated by three kinds of fluorides : (1) 0.05% NaF solution, (2) 1.23% APF gel and (3) 0.1% fluoride varnish. Diagnodent scores and microhardness (VHN) were measured before and after the each treatment. The results were as follows: 1. Diagnodent scores decreased to 23.51% from the initial after demineralization, and then increased to 37.37% after laser irradiation, and to 51.34% after fluoride treatment. There were significant differences between the total scores of initial, demineralization, laser irradiation and fluoride treatment (P<0.05). There was no significant difference between scores after fluoride treatment according to fluoride types. 2. Microhardness(VHN) decreased to 33.58% from the initial after demineralization and then increased to 43.99% after laser irradiation, and to 51.38% after fluoride treatment. There were significant differences between the total scores of initial, demineralization, laser irradiation and fluoride treatment (P<0.05). There was no significant difference between scores after fluoride treatment according to fluoride types.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.4
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• pp.532-536
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• 2010

Hidden caries is a subtype of the occlusal pit and fissure caries type and is defined as a dentinal caries lesion near the occlusal surface of the tooth seen on a radiograph. In visual examination, the occlusal enamel is seen intact or is minimally perforated. Covert caries, Occlult caries or Fluoride syndrome are used as synonym. The percentage of occlusal dentin lesions that are clinically undetected ranges from 1.4-50%. Little is known about the mechanisms involved in the development of hidden caries. But it is thought that extensive use of topical fluoride or the special bacteriological profile has been a major factor. This case report is about detection and treatment of hidden caries of two children who visited the department of pediatric dentistry, Yonsei University Dental Hospital. The color of caries dentin found in hidden caries lesion is lighter than cavity forming caries, which makes it more difficult to detect caries by visual examination. Therefore diagnosis of hidden caries is often accomplished after clinical sign is recognized by patients. The use of advanced caries detection aids such as Diagnodent.. with periodic radiographic examination is seemed to be helpful for early detection of hidden caries.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.1
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• pp.153-160
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• 2003

The purpose of study was to evaluate the effects of the $CO_2$ laser irradiation on demineralization inhibition and rehardening of human primary tooth enamel by laser fluoresecence measurement. Enamel specimens were made from the human primary teeth. The center spots of the specimens about 2 mm diameter were irradiated by $CO_2$ laser at the conditions of focused continuous or defocused pulsed, 3 or 6 W, for 4 seconds, before or after the demineralization by Coca-Cola for 24 hours at $37^{\circ}C$. The Diagnodent was used to measure the degree of demineralization and rehardening. There was no significant difference between focused continuous and defocused pulsed irradiation. 6W irradiation inhibited the demineralization but 3W did not. 6W irradiation rehardened the demineralized enamel but 3W did partially. The color of enamel was changed to brown to black after 6W irradiation but 3W caused no color change. $CO_2$ laser irradiation showed the effects on demineralization inhibition and rehardening of human priamary tooth enamel, and the laser fluoresecence measurement technique seemed to be a valid evaluation method.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.3
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• pp.345-351
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• 2010

The purpose of this study is to compare microleakage and penetration depths of sealants applied in carious and sound fissures. Extracted premolars(n=80) were divided into 4 groups according to caries status. 1; sound, 2; stained, 3; initial caries, 4; enamel caries. Sealants were applied to the occlusal groove as per manufacturers' instructions, and specimens were thermocycled, stained, sectioned, and examined for microleakage and penetration ability. The results of the present study are as follow: 1. It showed significantly higher microleakage scores in group I than group Two, Three, Four(p<0.05), but no significant difference was found between group Two, Three, and IV(p>0.05). 2. It showed significantly higher penetration scores in group Four (p<0.05), followed by group One, Two, Three, but no significant difference was found between group One, Two, and Three(p>0.05). Based on the results of present study, when the borders of the fissure sealant are on carious enamel, a significantly higher microleakage must be expected. It is considered that depth of enamel caries in the fissure should be taken into account when applying a fissure sealant.

• Journal of dental hygiene science
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• v.9 no.5
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• pp.557-561
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• 2009

The purpose of this study was to observe the demineralization effects of commercial drinks on bovine enamel. 12 bovine teeth without dental caries were divided into 3 experimental groups (n = 9) and control groups (n = 3). All the samples immersed in beverages maintained by $37^{\circ}C$ in incubator respectively. The differences of surface microhardness values(${\Delta}VHN$) between before and after 45 hours treatment were $166.97{\pm}51.69$(in Coca-cola), $116.26{\pm}20.81$(in Gatorade), $77.89{\pm}55.88$(in Hite), and $23.44{\pm}29.97$(in Jeju SamDaSoo). Morphological changes by scanning electron microscope were indicated that a sports drink cause significant enamel demineralization effects on the bovine enamel surface among four beverages.