• Journal of the Korea Convergence Society
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• v.8 no.6
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• pp.139-145
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• 2017

The aim of this study was to measure the remineralization effect of APF gel and fluride varnish on artificial enamel caries using CLSM in vitro. The samples were divided into 3 groups: control, 1.23% APF gel, 5% NaF varnish. The specimen surfaces were observed by CLSM and measured average fluorescence of the lesion(AFL). The results were analyzed using one-way ANOVA and Pearson's correlation analysis at a significance level off 0.05(PSWA 18.0, SPSS Inc., USA). There were significant differences between AFL at baseline and 1 day after fluoride application(p<0.05) but there are no significant differences between ${\Delta}$ AFL of all groups (p=0.222). Result of Pearson's correlation analysis, there are no significant correlation between VHN and AFL, but there were significant correlation between AFL at baseline and 1 day after fluoride application(r=0.811, p<0.001). Although AFL decreased after fluoride application, but there was no difference between the groups. In the future, it is necessary to test the oral environment model or in situ experiment supplemented the limitations of this study.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.3
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• pp.512-521
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• 2001

Recently. the reintroduction of air-abrasion technology in dentistry has added a new potential method of pretreating teeth prior to placing sealants. The purpose of this in vitro study was to investigate microleakages of several pit and fissure sealants following various surface pre-treatment methods to the enamel, because there was a question concerning the validity of claim that this method was better than the conventional acid etching. Permanent molars were divided randomly into nine groups and treated accordingly: acid etching(group 1, 4, 7), air-abrasion(group 2, 5, 8), acid etching after air-abrasion(group 3, 6, 9). Then the authors placed and cured the three kinds of sealants(group $1\sim3$: Teethmate-F, group $4\sim6$: Ultraseal XT plus, group $7\sim9$: Denseal) according to the manufacturer's order. They were observed to determine the degree of microleakage. And these specimens were separated from the corresponding enamels and examined by Scanning Electron Microscope. The following results were obtained: 1. In comparing microleakage among tooth surface treatment methods, air-abrasion group(group 2, 5, 8) showed the greatest microleakage, while combination(air-abrasion + acid etching) group showed the least (p<0.05). However, no significant differences were found between group 7 and 9. 2. The mean microleakages were ranked as follows(p<0.05): In acid etching groups, group 7> group 4> group 1. In air-abrasive groups, group 8>groups 5> group 2. In combination groups, group 9>group 3> group 6. However, no significant differences were found between group 4 and 7 between group 2 and 5 and between group 3 and 6. 3. SEM showed that comparably longer resin tags were distributed regularly in acid etching groups and that shorter ones irregularly in air-abrasion groups. It also showed that these two kinds of tags were distributed simultaneously in combination groups.

• The korean journal of orthodontics
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• v.34 no.5 s.106
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• pp.439-447
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• 2004

The purpose of this study was to investigate the influence of water, saliva and blood contamination on the bonding strength of metal brackets with a self-etching primer/adhesive to enamel. Ninety-six extracted human teeth were divided into four groups. The brackets were bonded to enamel with a self- etching primer (3M/Unitek Dental Products. Monorovia California) according to one of four protocols. The teeth were bonded in a dry condition (group D) or in contamination with distilled water (group W), artificial saliva (group S). or fresh human blood (group B) Shear bond strengths were tested using an Instron Universal testing machine. After debonding. bracket and tooth surfaces were examined with a stereomicroscope. In each group, four samples were selected and examined with a Scanning electron microscope of the prepared enamel surface and resin-enamel interlace. The results obtained were summarized as follows: Shear bond Strength if group D $(15.22{\pm}2.86MPa)$ and W $(15.20{\pm}3.85 MPa)$ Were higher than in group B$(12.56{\pm}2.94MPa)$ (p<0.05). There were no statistical differences in the shear bond strengths between groups D. W and S (p>0.05). There was a tendency to have less residual adhesive remaining on the enamel surfaces of group B than group D. The SEW morphology of group D and W showed a more roughened etching pattern than group S and B. Water or saliva contamination on bending of orthodontic brackets with Transbond plus self etching primer had almost no influence on bond strength In this study, the blood contaminated group showed the lowest bond strength, but it was above the clinically acceptable bond strength (5.9-7.8 MPa, Reynold, 1975). The results of this study suggest that acceptable clinical bond strengths can be obtained in wet conditions when self-etching adhesives are used.

• Journal of dental hygiene science
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• v.14 no.4
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• pp.597-609
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• 2014

To find out the effect of commercially available energy drinks on tooth enamel erosion, analyzed pH, buffering capacity, and the content of some of the inorganic components selecting 4 energy drinks that has high affinity of the products currently being sold. In addition, by observing the degree of erosion before and after immersion in energy drink by surface microhardness and scanning electron microscope (SEM) the results were as follows: Acidity of energy drink 'Burn Intense' was the lowest as $2.78{\pm}0.01$ highest on distilled water as $6.475{\pm}0.01$. 'Burn Intense' buffering capacity was $3.48{\pm}0.155$ at pH 5.5, $1.88{\pm}0.15$ at pH 7.0 which is the highest, and 'Hot6' was $1.71{\pm}0.37$, $1.23{\pm}0.35$ on each of it showing the lowest points. Ca content on energy drink was the highest at 'Volt Energy' as ($77.21{\pm}2.70mg/kg$), the lowest at 'Hot6' as ($0.98{\pm}0.05mg/kg$). P content was the highest on 'Hot6'($1.34{\pm}0.05mg/kg$) and detected at 'Red Bull'. Enamel surface hardness variation of the energy drinks before and after immersion showed rapid decrease at 'Red Bull' ($66.65{\pm}35.60$), and 'Volt Energy' ($61.96{\pm}31.42$), 'Burn Intense' ($58.53{\pm}24.84$), 'Hot6' ($53.99{\pm}60.26$) was in order. Distilled water, the control group, showed significant difference with the experimental group (p<0.05). But there was no significant difference between energy drinks. At SEM observation and analysis, 'Burn Intense' was the most severe demineralization, 'Volt Energy', 'Hot6', 'Red Bull', distilled water was in order. In the above results, taken together there were no statistically differences between energy drinks but significant difference in comparison with distilled water. In addition, at SEM observation and analysis all energy drink caused dental erosion, especially 'Burn Intense', has the lowest acidity, was serious. Thus, it is believed to provide a variety of oral health education and information about energy drinks that can affect the erosion of the teeth so public have the right to be recognized and reasonable dental care.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.4
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• pp.348-354
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• 2011

Composite resin has been widely used for eroded enamel. But, as there have been many reports about the differences in physicochemical characteristics of eroded enamel compared with sound enamel, an additional effort was thought necessary to obtain the optimal bond strength. As a possible answer, we came to think about the application of infiltrant resin which is known to have an excellent penetration capacity into enamel. This study was performed for the purpose of comparing the bond strength of composite restoration with or without infiltrant resin under adhesives on the artificially eroded enamel. 60 extracted sound maxillary primary incisors were selected and divided into group 1, 2, 3 according to the number of artificial erosion cycling for 5 minute duration in 1% citric acid of pH 3.2 at $37^{\circ}C$. And the labial surfaces were divided into 3 areas; group A, only resin adhesive was used, group I, only infiltrant resin, group IA, infiltrant resin followed by resin adhesive. Afterwards, every specimen was restored with composite resin. Microtensile bond strength was measured and failure modes were observed. The obtained results were as follows: 1. In comparing the bond strength by the degree of enamel erosion, it was revealed the highest bond strength in group 1, followed by group 2 and 3, showing the lowest bond strength in most eroded group(p<0.05). 2. In comparing the bond strength by surface treatment methods, group IA and I showed higher value than group A(p<0.05), with unsignificant difference between group I and IA(p>0.05). 3. In observation of failure mode, it was shown higher frequency of cohesive failure in order of 1-2-3 and IA-I-A. Conclusively, it was shown decreasing tendency of bond strength as the enamel is more eroded, and infiltrant resin was thought helpful to replace or add to the resin adhesive for optimal bonding with eroded enamel.

• 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 Rehabilitation and Applied Science
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• v.32 no.3
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• pp.149-157
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• 2016

Tooth preparation design is essential for successful laminate veneer treatment. Preservative tooth preparation limited on enamel, supra-margin advantageous for plaque control, and maintaining contact points known as a standard concept. However, the tooth preparation design has been the controversial issue. In biomechanical considerations, the incisal coverage should be decided on esthetic needs and necessity for the anterior guidance reconstruction. In occasion for sufficient enamel thickness, preparation can prolong to the palatal side but not recommended at palatal concavity. Elongation to contact point is selective option according to the cases. If an old resin restoration located at contact area, laminate veneer should cover over half area of that after surface treatment. The laminate veneer can be also selected at a partially discolored tooth root canal therapy (RCT) and at this occasion, the fiber-reinforced composite (FRC) posts are recommended.

• Restorative Dentistry and Endodontics
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• v.31 no.6
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• pp.452-459
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• 2006

Competition will usually develop between the opposing walls as the restorative resin shrinks during polymerization. Magnitude of this phenomenon may be depended upon cavity configuration and volume. The purpose of this sturdy was to evaluate the effect of cavity configuration and volume on microleakage of composite resin restoration that has margins on the enamel site only. The labial enamel of forty bovine teeth was ground using a model trimmer to expose a flat enamel surface. Four groups with cylindrical cavities were defined, according to volume and configuration factor(Depth x Diameter / C-factor) - Group I : 1.5 mm ${\times}$ 2.0 mm / 4.0, Group II : 1.5 mm ${\times}$ 6.0 mm / 2.0, Group III : 2.Omm ${\times}$ 1.72 mm / 5.62, Group IV : 2.0 mm ${\times}$ 5.23 mm / 2.54. After treating with fifth-generation one-bottle adhesive - BC Plus$^{TM}$ (Vericom, AnYang, Korea), cavities were bulk flted with microhybrid composite resin - Denfill$^{TM}$ (Vericom). Teeth were stored in distilled water for one day at room temperature and were finished and polished with Sof-Lex system. Specimens were thermocycled 500 times between 5$^{\circ}$C and 55$^{\circ}$C for 30 second at each temperature. Teeth were isolated with two layers of nail varnish except the restoration surface and 1 mm surrounding margins. Electrical conductivity (${\mu}$A) was recorded in distilled water by electrochemical method. Microleakage scores were compared and analyzed using two-way ANOVA at 95% level. The results were as follows: 1. Small cavity volume showed lower microleakage score than large one, however, there was no statistically significant difference. 2. There was no relationship between cavity configuration and microleakage. Factors of cavity configuration and volume did not affect on microleakage of resin restorations with enamel margins only.

• Journal of the korean academy of Pediatric Dentistry
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• v.46 no.2
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• pp.190-199
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• 2019

$Carbopol^{(R)}$ 907 used as surface protecting agent in White's method is the one of the artificial caries lesion producing solution was discontinuing of production. New surface protecting material to substitute of $Carbopol^{(R)}$ 907 was required. The author prepared an artificial caries lesion producing solution as follows White's method with $Carbopol^{(R)}$ 907 and also another artificial caries lesion producing solution with $Carbopol^{(R)}$ $2050^{(R)}$. 96 flattened and polished enamel samples were immersed in a demineralizing solution of 0.1 mol/L lactic acid, 0.2% carboxyvinylpolymer and 50% saturated hydroxyapatite for 1, 2, 3, 4, 5, 6, 7, 9, 11, 15, 18 and 20 days. All samples from each group were subjected to polarized microscopy observed and image analysis for measuring the lesion depth. From the review of polarized images, the artificial caries lesion producing solution using $Carbopol^{(R)}$ 907 and $Carbopol^{(R)}$ 2050 can produced an artificial caries that was very similar to natural caries characters. From the regression analysis of the lesion depth produced by the artificial caries lesion producing solution using $Carbopol^{(R)}$ 907 and $Carbopol^{(R)}$ 2050, $Carbopol^{(R)}$ 2050 estimate as Y = 9.8X + 8.0 and $Carbopol^{(R)}$ 907 was Y = 8.4X - 0.4. R square value of $Carbopol^{(R)}$ 2050 and $Carbopol^{(R)}$ 907 was 0.965 and 0.945 respectively. The rate of demineralization by the artificial caries lesion producing solution using $Carbopol^{(R)}$ 2050 was faster than that of $Carbopol^{(R)}$ 907. And R square value of $Carbopol^{(R)}$ 2050 and $Carbopol^{(R)}$ 907 were very high and it means that the lesion depth was very high coefficient to demineralization period.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.3
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• pp.423-430
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• 2003

The teeth bleaching with bleaching agent is widely used at recent times. Until yet the exact mechanism of the bleaching agent isn't known but it is thought that is by the complex reduction-oxidation reaction of the decomposed free radical from bleaching agent through various ways. In other words, it is supposed that the teeth are whitened by agent's changing chemical structures of stain-causing materials. The purpose of this study is to exam the change of the dentinal character by bleaching agent and to evaluate the safety of this agent. For this study, after applying 10% carbamide peroxide to enamel of human premolar for 6 hours a day for 2 weeks we examined changes of surface morphology, microhardness, composition and contents of minirals in human dentin using SEM, microhardness tester, FT-Raman spectrometer and EPMA and got following results. There was no significant difference in surface morphologic change when we examined the effect of 10% carbamide peroxide which penetrated into dentin after applied on enamel surface comparing with result from specimen in distilled water No change was shown on the surface of peritubular and intertubular dentin within the nanometeric range. The microhardness between bleached teeth and teeth stored in distilled water showed no statistically significant difference FT-Raman spectra of dentin exhibited no change of the component in human dentin. Only the least change in peaks of organic and inorganic materials were detected in Raman intencity. The total content of mineral elements in dentin with no treatment, stored only in distilled water and stored in distilled water after bleaching were $98.73{\pm}1.89,\;98.56{\pm}2.11\;and\;97.47{\pm}2.51$ respectively. Also they showed no statistically significant difference. From above results, the effect of 10% carbamide peroxide bleaching on structure of dentin is very low and the results may confirm the safety of this bleaching agent.