• Journal of dental hygiene science
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• v.19 no.3
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• pp.154-161
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• 2019

Background: The market for vitamin drinks is expanding both in Korea and worldwide. However, it was difficult to find studies regarding the possibility of tooth erosion induction due to vitamin drinks. The purpose of the present in vitro study was to evaluate the effect of tooth erosion caused by a few commercial vitamin beverages on bovine teeth enamel in terms of erosion depth and fluorescence loss. Methods: Three experimental groups (vitamin drinks), a positive control group (Coca-Cola), and a negative control group (mineral water) were established. Each group consisted of 5 specimens obtained from sound bovine teeth. The pH and titratable acidity of beverages were measured. Specimens were immersed in the beverages and artificial saliva for 6 and 18 hours, respectively. This cycle was repeated for 5 days. The depth of the tooth loss caused by tooth erosion (erosion depth) and maximum loss of fluorescence (Max ${\Delta}F$) were measured using the microscope and quantified light-induced fluorescence-digital, respectively. For the statistical analysis, the Kruskal-Wallis test and ANOVA were used to compare the erosion depth and Max ${\Delta}F$ of the enamel surfaces. In addition, Spearman correlations were estimated. Results: The pH of the three vitamin beverages ranged from 2.65 to 3.01, which is similar to that of the positive control group. All beverages, except mineral water, had sugar and acidic ingredients. Vitamin drinks and the positive control, Coca-Cola, caused tooth erosion lesions, and showed significant differences in erosion depth compared to mineral water (p<0.05). The vitamin beverages with low pH were associated with high erosion depth and Max ${\Delta}F$. Conclusion: Vitamin drinks have the potential to cause tooth erosion.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.1
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• pp.112-124
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• 1997

According to extensive use of composite resin which have superior esthetic property, every effort on improving bonding strength between a tooth and composite resin has been continued. Acid etching technique is a method that micro-etches the tooth surface which provides bonding with composite resin possible. Recently, there were several reports that mechanical treatment obtained from air-abrasion can provide similar bonding strength with acid etching technique. So, this experimental study was designed to compare the shear bonding strength between using air-abrasion technique and using acid etching technique. Initially, bovine teeth were divided into enamel and dentin experimental groups. Respectively each group was categorized into three subgroups. One subgroup was acid etched with 35% phosphoric acid, then bonded with composite resin. The other subgroup was air-abraded with $50{\mu}m$ $Al_2O_3$ particles sprayed with 160psi air pressure using air abrasion unit(KCP-1000, A.D.T., U.SA), and composite resin was bonded. In another subgroup, composite resin was bonded after acid etching following air-abrasion. So, enamel experimental groups were made of E1 (acid etched only), E2(air-abraded only), E3(acid etched following air-abraded), and dentin experimental groups were made of D1(acid etched only), D2(air-abraded only), D3(acid etched following air-abraded). Each subgroup had 10 specimens. Dentin bonding system(Scotchbond Multi-purpose, 3M Co., U.S.A.) and composite resin(Z-100, 3M Co., U.S.A.) were applied on treated surface using 5mm diameter gelatin capsule as manufacturer's direction. After 1200 times thermocycling between $5^{\circ}C$ and $55^{\circ}C$, shear bond strength was measured in 5mm/min crosshead speed with Instron(Instron Co., U.S.A.), and also treated enamel and dentin were observed with SEM(JEOL Co., Japan). The following results were obtained: 1. In the enamel experimental groups, acid etched following air-abraded group had highest shear bond strength, but there was no significant difference compared to acid etched group. Air-abraded only group had lowest shear bond strength, and there was significant difference compared to the rest of groups. 2. In the dentin experimental groups, acid etched following air-abraded group had highest shear bond strength, but there was no significant difference compared to acid etched group. Air-abraded only group had lowest shear bond strength, and there was significant difference compared to the rest of groups. 3. In the SEM study, air-abraded enamel and dentin had irregular and rough surfaces.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.3
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• pp.266-276
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• 2020

The purpose of this study was to compare the remineralization effect of 38% silver diamine fluoride (SDF) and 5% sodium fluoride (NaF) varnish on artificially induced enamel caries. The present study standardized the physiochemical characteristics of the tooth structure using bovine teeth, realized the wash-off action of agents using a saliva, reproduced an environment similar to mouth through pH-cycling, and comparatively assessed the remineralization effect of 38% SDF and 5% NaF varnish in a non-destructive method using micro-CT. And the remineralized enamel surface structure was analyzed by scanning electron microscopy (SEM) and energy dispersive X-Ray spectroscopy (EDS). In both SDF and NaF varnish, mineral density (△Hounsfield unit value) and the volume of enamel restored to normal mineral density through remineralization gradually increased with time. And the SDF showed a much higher level of increase in mineral density at all depths and remineralized volume than NaF varnish. According to SEM analysis, the surface roughness decreased in the order of artificial saliva, NaF varnish and SDF. In addition, EDS analysis showed that silver ion was precipitated on the enamel surface in SDF group. In conclusion, SDF had a greater remineralization effect than NaF varnish on demineralized enamel.

• Journal of dental hygiene science
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• v.15 no.4
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• pp.419-423
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• 2015

Recently, energy drink consumption is rising. The purpose of this study was to examine the effect of energy drink on enamel erosion by measuring pH and titratable acidity in energy drink on the market. pH and titrable acidity in drink were measured by selecting 3 kinds of energy drinks with high sales volume among energy drinks on the domestic market. To evaluate the erosion level of normal enamel, the erosion level was measured by using a surface micro-hardness after soaking it in drink for 1 minute, for 3 minutes, for 5 minutes, for 10 minutes, and for 30 minutes while using 10 pieces of bovine specimens per each group. All the energy drinks were containing citric acid. As for pH in drinks, pH of Burn intense was the lowest with $2.51{\pm}0.01$. Hotsix stood at $3.16{\pm}0.01$. Redbull stood at $3.37{\pm}0.00$. In pH 5.5, the titrable acidity of Burn intense was 3.59 ml. Redbull was 3.43 ml. Hotsix was 1.92 ml. All the energy drinks were reduced the surface micro-hardness according to a rise in time of immersion. Following the 30-minute treatment in drinks, the surface micro-hardness value was indicated to be the lowest in Redbull with $119.72{\pm}15.16$ VHN. It was shown to be in order of Hotsix $208.75{\pm}10.99$ and Burn intense $210.47{\pm}8.01$. Hotsix and Burn intense had no statistically significant difference (p>0.05). Accordingly, all the energy drinks, which were used in the experiment, caused the tooth enamel erosion. Among them, Redbull led to the largest enamel erosion. Thus, energy drink containing citric acid and low pH can cause the enamel erosion. However, it is thought to be necessarily progressed by considering factors of influencing etching a little more diversely by additionally analyzing intraoral factors, acid kinds, and even the content in calcium, phosphate and fluoride.

• Journal of dental hygiene science
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• v.9 no.5
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• pp.525-530
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• 2009

The purpose of this study was to evaluate color change and enamel surface changes using the plasma arc light source during tooth bleaching treatments. Twenty-four extracted bovine incisors were selected and embedded in the resin blocks. All the specimens were highly polished and discolored with commercial $COCK^{(R)}$. High concentration carbamide peroxide with and without plasma arc were used for bleaching. Specimens were bleached for 1 hour per week during 3 weeks. Color and enamel surface changes were determined with colorimeter (TC-8600A), microhardness tester(MXT-a7), scanning electron microscope(S-4200). All the collected data analyzed with paired t-test, t-test and one-way ANOVA. After the bleaching, both groups showed the color changes(${\Delta}E^*$). Microhardness of two group decreased after tooth bleaching. The SEM evaluation of enamel surface of both group showed a similar morphology of decalcification after tooth bleaching. Office bleaching using the plasma arc application with 35% carbamide peroxide can increase the color change. Office bleaching using the high concentration of carbamide peroxide and plasma arc also detract the outer surface of enamel. It is recommended that careful procedures are needed during office bleaching with high concentration of carbamide peroxide and light source.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.2
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• pp.148-156
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• 2008

Statement of problems: Self-etch adhesives exhibit some clinical benefits such as ease of manipulation and reduced technique-sensitivity. Nevertheless, some concern remains regarding the bonding effectiveness of self-etch adhesives to enamel, in particular when so-called 'mild' self-etch adhesives are employed. This study compared the microtensile bond strengths to ground enamel of the two-step self-etch adhesive Clearfil SE Bond (Kuraray) to the three-step etch-and- rinse adhesive Scotchbond Multi-Purpose (3M ESPE) and the one-step self-etch adhesive iBond (Heraeus Kulzer). Purpose: The purpose of this study was to determine the effect of a preceding phosphoric acid conditioning step on the bonding effectiveness of a two-step self-etch adhesive to ground enamel. Material and methods: The two-step self-etch adhesive Clearfil SE Bond non-etch group, Clearfil SE Bond etch group with prior 35% phosphoric acid etching, and the one-step self-etch adhesive iBond group were used as experimental groups. The three-step etch-and-rinse adhesive Scotchbond Multi-Purpose was used as a control group. The facial surfaces of bovine incisors were divided in four equal parts cruciformly, and randomly distributed into each group. The facial surface of each incisor was ground with 800-grit silicon carbide paper. Each adhesive group was applied according to the manufacturer's instructions to ground enamel, after which the surface was built up using Light-Core (Bisco). After storage in distilled water at $37^{\circ}C$ for 1 week, the restored teeth were sectioned into enamel beams approximately 0.8*0.8mm in cross section using a low speed precision diamond saw (TOPMET Metsaw-LS). After storage in distilled water at $37^{\circ}C$ for 1 month, 3 months, microtensile bond strength evaluations were performed using microspecimens. The microtensile bond strength (MPa) was derived by dividing the imposed force (N) at time of fracture by the bond area ($mm^2$). The mode of failure at the interface was determined with a microscope (Microscope-B nocular, Nikon). The data of microtensile bond strength were statistically analyzed using a one-way ANOVA, followed by Least Significant Difference Post Hoc Test at a significance level of 5%. Results: The mean microtensile bond strength after 1 month of storage showed no statistically significant difference between all adhesive groups (P>0.05). After 3 months of storage, adhesion to ground enamel of iBond was not significantly different from Clearfil SE Bond etch (P>>0.05), while Clearfil SE Bond non-etch and Scotchbond Multi-Purpose demonstrated significantly lower bond strengths (P<0.05), with no significant differences between the two adhesives. Conclusion: In this study the microtensile bond strength to ground enamel of two-step self-etch adhesive Clearfil SE Bond was not significantly different from three-step etch-and-rinse adhesive Scotchbond Multi-Purpose, and prior etching with 35% phosphoric acid significantly increased the bonding effectiveness of Clearfil SE Bond to enamel at 3 months.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.2
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• pp.377-398
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• 1999

Calcium fluoride, created by topical fluoride application, is the reservoir for fluoride ion regulated by pH in the oral environment. Therefore, the amount and the maintenance of calcium fluoride have an important role in preventing dental caries. The aim of this study is to evaluate the effect of Nd:YAG laser irradiation on the generation of calcium fluoride and the acid resistance of tooth enamel. The bovine anterior permanent teeth were prepared (n=276), and divided into following groups : no treatment (control) fluoride application alone, laser irradiation alone, laser irradiation after fluoride application, and fluoride application after laser irradiation. And each group was subdivided based on the application time of 1.23% acidulated phosphate fluoride (APF) (5 min and 30 min) and the irradiation energy of Nd:YAG laser ($20J/cm^2\;and\;40J/cm^2$). In case of fluoride application, each group was divided according to KOH treatment. Twenty three treatment conditions were made for this experiment and twelve specimens were assigned to each treatment condition. In each treatment condition, ten specimens were used for chemical analysis and two specimens were observed under SEM. In groups without treating KOH, fluoride content and the depth of enamel dissolved were measured using enamel biopsy technique. In groups with treating KOH, the amount of calcium fluoride was measured by the treatment with 1 M KOH for 24 hours and enamel biopsy was performed after KOH treatment. The results were analyzed by the fluoride content and the depth of enamel dissolved by enamel biopsy, amount and thickness of calcium fluoride, and the surface structures of enamel. The results are as follows: 1. In groups without treating KOH, the fluoride content of removed enamel showed a positive relationship with the energy density of laser when the laser irradiated before fluoride application 2. In groups without treating KOH, the depth of enamel dissolved decreased more with the combined laser and fluoride treatment than with laser or fluoride treatment, except for the case of $20J/cm^2$ laser irradiation after 5 minute fluoride application (p<0.05). 3. The amount of calcium fluoride did not increased by laser treatment with no statistical significance(p>0.05). 4. The particle size of calcium fluoride increased in case of fluoride treatment after laser irradiation, compared with fluoride application alone. In case of laser treatment after fluoride application, the particle size of calcium fluoride increased and some of the particles fused as well. 5. There were no significant differences in the fluoride content of dissolved enamel between groups without treating KOH and control group, except for the case of laser irradiation after treatment of APF for 30 minutes (p>0.05). 6. In groups with treating KOH, depth of removed enamel in the groups of combined treatment with laser and fluoride was shallower than that in fluoride application groups (p<0.05). 7. In groups without treating KOH, the relationship between fluoride content and the depth of enamel dissolved showed more negative (Spearman correlation coefficient: -0.6281) than in groups with treating KOH (Spearman correlation coefficient: -0.3792). The greater amount of calcium fluoride could be found in case where there was a significant differences of the depth of enamel dissolved between groups with and without treating KOH. From these results, it can be concluded that laser seems to be a little effects on the amount of calcium fluoride formation, but has some effect on the lowering the solubility of calcium fluoride. As the combined treatment of laser and fluoride application showed more effective acid-resistant property, more extended recall period for fluoride application can be achieved with this combined treatment in the clinic.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.2
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• pp.183-191
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• 2007

Through out the world dental caries seems to be decreased as it is difficult to make an accurate diagnosis for dental caries. The traditional diagnostic method which is probing and x-ray taking has many limitations to diagnose the early caries, so there were recommendations for the needs of new equipments such as laser fluorescence(LF), digital imaging fiber-optic trans-illumination(DIFOTI), and quantitative light fluorescence (QLF) which were developed from various study results. Also confocal laser scanning microscopy(CLSM) and ultrasonics are used for research progression. This study is to evaluate whether it is possible to monitor accurately for remineralization amount of enamel surface early caries using DIFOTI or LF After inducing artificial caries to bovine teeth to 10 participants remineralization was enhanced by 0 ppm and 500 ppm fluoride mouth rinse solution for 3 weeks. Then they were cross sectioned and analyzed using gold standard of the lesion depth measured by CLSM. The following results were obtained: 1. The measured percentage of light intensity(luminosity ratio) by DIFOTI increased with remineralization period, and showed significant reverse correlation with lesion depth measured by CLSM (p<0.01). 2. The measurement of laser fluorescence increased with remineralization period, and showed significant correlation with lesion depth measured by CLSM (p<0.01). 3. To the result for CLSM, 500 ppm fluoride mouth rinse group showed rapid rate for decreased tendency of lesion depth than 0 ppm fluoride mouth rinse group. In conclusion DIFOTI system was used to measure accurately for the remineralization amount of early surface caries, it is a very useful equipment to detect precisely the changes for early enamel caries remineralization during treatments.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.1
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• pp.109-118
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• 1999

The aim of this study was to evaluate the optical density of laser fluorescence for detection of incipient caries. Prepared and polished bovine enamel specimens were demineralized in a STPP solution for varying periods of time between 3 hrs. and 60 hrs. with an area of sound enamel retained on each specimen. The randomized specimens were analyzed for optical density of enamel demineralization using laser fluorescence. The specimens were sectioned and examined lesion depth by polarizing light microscope. Results were analyzed statistically with SAS program. The results from this study can be summarized as follows: 1. Optical density measured by laser fluorescence and lesion depth measured by polarizing light microscope was increased as demineralization time was increased(p<0.001). 2. Between optical density measured by laser fluorescence and lesion depth measured by polarizing light microscope was correlated highly(${\gamma}{\geq}0.74956$, p<0.001). 3. Regressive equation was obtained in this study as follows. Y=[X-0.260851]/0.000271(R-square:0.5618, p<0.001) (X:DENSITY, Y:DEPTH) In summary, optical density measured by laser fluorescence would be within the range of possibility to quantitatively presume demineralization amount of incipient caries lesion

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.1
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• pp.1-9
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• 2003

To evaluate the quantitative nature of laser fluorescence(LF) and dye-enhanced laser fluorescence(DELF) on early enamel caries, artificial caries were induced on the bovine enamels and argon laser was irradiated on the surfaces of lesions. Fluorescence radiance from enamel specimen was recorded with CCD camera which was connected to PC image analyzing system. The difference of fluorescence of radiance(DFR) between the carious and the sound enamel in each sample of the LF and the DELF groups were measured by image analyzing program. The DFR of lesion surfaces measured with laser fluorescence and lesion depths were evaluated and the results are as follows: The caries lesions were discriminated from sound enamels by the darkness with LF and by the brightness with DELF. The DELF was more sensitive than the LF at the earlier stage of demineralization.