• Restorative Dentistry and Endodontics
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• v.29 no.1
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• pp.36-43
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• 2004

The purpose of this study was to compare the microhardness and the fluoride content of enamel and dentin around fluoride- or non fluoride-containing restorations. Forty extracted human teeth were used and prepared cervical cavities on proximal surface. Experimental teeth were divided into five groups . Group 1 : Prime & Bond NT and Z100, Group 2 Prime & Bond NT and F2000, Group 3 : Scotchbond Multi-purpose and Z100, Group 4 : Scothcbond Multi-purpose and F2000, Group 5 : Fuji II LC. The cavities were filled with dentin adhesives and restorative materials. After each tooth was bisected, one half was tested microharaness and the other half was analyzed the fluoride at the enamel and dentin by an EPMA-WDX device. The results were as follows; 1. There was no statistical difference among the microhardness of enamel surface in all group. 2. The microhardness at dentin of $100{\;}\mu\textrm{m}$ point in Group 2 and $20{\;}\mu\textrm{m}$ point in Grocup 4 was lower than that of normal dentin (p>0.05). 3. There was no statistical difference among the fluoride content of enamel surface in all group. 4. The fluoride content at the dentin of $30{\;}\mu\textrm{m}$ point in Group 2 and 5 were higher than those at $100{\;}\mu\textrm{m}{\;}and{\;}200{\;}\mu\textrm{m}$ point in Group 2 and normal dentin (p<0.05). 5. At the dentin of $30{\;}\mu\textrm{m}$ point, Group 2 showed higher fluoride content than Group 1 and 3, and Group 5 showed higher fluoride content than other groups.

• Journal of the korean academy of Pediatric Dentistry
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• v.10 no.1
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• pp.85-93
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• 1983

In one group that tested for the effects of grinding and etching on the deciduous teeth, S.E.M. examination on the ground or unground labial surface of deciduous maxillary central incisors were made after etching procedure with 40% phosphoric acid for 60 secs., 120 secs., 180 sees. each. In another group that tested for the degree of resin penetration to the ground and etched deciduous teeth, composite resin application was done to the ground deciduous maxillary central incisors that had been acid-etched for 30 secs., 60 secs., 90 sees., 120 sees., 180 secs. each. The tooth-resin specimens were cut at the middle 1/3 of the crown by 2mm thickness, and the adjacent tooth materials were demineralized by 10% hydrochloric acid, the author observed the tags of the resin replica with S.E.M.. Following results were obtained. 1. After 40% phosphoric acid etching, the unground deciduous enamel surface showed various types of etching pattern. 2. For the formation of regular micropores on deciduous enamel surface by acid etching with 40% phosphoric acid, the time over 120 secs. should be requested. 3. After 40% phosphoric acid etching, the ground deciduous enamel surface showed the same etching pattern that has been a preferential removal of prism peripheries despite different etching time. 4. On the ground group that etched over 60 secs. to 180 secs., the length of tags was $5{\mu}m$ to $8{\mu}m$, with a mean of $7{\mu}m$.

• 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.

• Journal of Oral Medicine and Pain
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• v.20 no.1
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• pp.7-18
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• 1995

The Purpose of this article is to describe the biochemical properties and biological functions of several salivary proteins that possess the unusual properties of inhibiting spontaneous and secondary precipitation of calcium phosphate. This function is very important since human salivary secretion is supersaturated with respect to calcium phosphate. Biological function of statherin, proline rich protein (PRP) and histidine rich protein (HRP) is to inhibit precipitation of calcium phosphate in salivary glands, in the oral fluids, and onto tooth surfaces. The resulting supersaturated state of the salivary secretions contributes a protective and reparative environment which is important for the integrity of the tooth. Beneficial consequences of salivary supersaturation with respect to calcium phosphate are selectively expressed in the oral cavity- that is, protection is provided for the dental enamel-while undesirable consequences, for example, precipitation of calcium phosphates in the salivary glands and onto the teeth do not occur. Purification and structural characteristics of these proteins as well as clinical significance of functions of each protein will be discussed.

• The Journal of Korean Academy of Prosthodontics
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• v.24 no.1
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• pp.33-43
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• 1986

The purpose of this study was to compare the wear resistance of heat pressure-cured microcomposite(SR-Isosit-N), photo-cured microcomposite(Dentalcolor), unfilled heat-cured resin(Thermojel) and that of human enmel. Specimens were made with specially designed die and finally polished with #3,000 diamond paste. After 100,000 strokes of tooth brushing at electric tooth-brushing machine, mean thickness loss of each specimen was measured by using surface profile and integration. The results were as follows 1. Mean thickness loss were $84.3{\pm}27.3{\mu}m$ in unfiled heat-cured resin, $9.4{\pm}2.5{\mu}m$ in photocured microcomposite, $7.6{\pm}2.1{\mu}m$ in heat.pressure-cured microcomposite and $0.97{\pm}0.42{\mu}m$ in enamel. 2. Heat.pressure-cured microcomposite and photo-cured microcomposite had no difference in mean thickness loss(p>0.05). 3. Unfilled resin and microcomposite had much differences in mean thickness loss (p<0.005). 4. ha resins used in this experiment had too much mean thickness loss as compared with enamel (p<0.005).

• Restorative Dentistry and Endodontics
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• v.5 no.1
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• pp.13-18
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• 1979

The purpose of this study was to measure the roughness on the acid -etching surface. The etching agents of three-kinds composite resins were used to etch the tooth surface. Newly extracted I5-anterior teeth were invested with self-curing acrylic resin, and the labial surface was exposed. The exposed labial side was polished with abrasive papers and finally polished on polishing machine with zinc oxide powder. After the teeth were polished, the specimens were washed by water and dried by air. Surface roughness tester, Taylor-Habson's Taly Surf-10, (Fig-1) was used to measure roughness of this unetched tooth surface. And that, the specimens were divided into three groups. The first group was etched with Restodent etchant, the second group was etched with Nuva-system etchant, and Hi-pol etching agent was used in the third group. And the surface roughness tester was used to measure roughness of the etching teeth surface. The results obtained were as follows. 1. The roughness of acid-etched enamel were increased $2{\mu}m$ to $6{\mu}m$. 2. Hi-pol etchant produced the smoothest surface($2.3{\mu}m$). 3. Restodent etchant($3.8{\mu}m$) and Nuva-system etchant($3.7{\mu}m$) produced rougher surface than Hi-pol.

• Restorative Dentistry and Endodontics
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• v.21 no.2
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• pp.470-488
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• 1996

The end products of the metabolism of the oral microorganism, organic acids, are an element that produces dental caries. Four organic acids in plaque fluid, lactic acid, acetic acid, succinic acid, propionic acid which take the important role in producing dental caries, were chosen to evaluate the effect of acid type and concentration. The subject, $100{\mu}m$ in thickness, were immersed in acid-buffer solution which has the different acid concentration of 10mM, 25mM, 50mM, 100mM and pH 4.3 and degree of saturation was $0.153{\pm}0.003$ kept in constant and were operated to produce artificial caries under different demineralization time (1, 2, 3 day) at x25. The results were obtained by observing under polarizing microscope at x25. 1. The subsurface lesion, specific finding of incipient enamel caries, showed positive birefringence. but surface zone and sound enamel showed negative birefringence. 2. The demineralization rate of enamel was increased as the acid concentration increased. 3. The subsurface lesion showed increasing depth in the order of lactic, acetic, propionic acid, succinic acid. 4. The concentration of organic acid in artificial caries system had an independent effect on demineralization rate in enamel under the constant pH and degree of saturation. The result of this study showed that not only pH and the acid strength but the concentration of organic acid had an independent effect on demineralization rate in early enamel caries. And through the further research on the factors influencing enamel demineralization, it will be necessary to develop an effective caries preventive therapy.

• The Journal of Korean Academy of Prosthodontics
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• v.40 no.5
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• pp.451-469
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• 2002

The purpose of this study was to estimate the effect of a bleaching agent on tooth surfaces and to evaluate the resin bond strength according to different surface treatments on bleached teeth. To prepare for the experimental samples, first, extracted human third molars were used and the body portions of the crowns were cut into four equal-sized specimens. Next, each specimen was mounted in an plastic bottle with self-cured resin and highly polished to have them reveal the enamel or dentin surfaces. Then, the enamel(E) and dentin(D) specimens were divided into four ; 1) non-bleached, laser-treated(NBLA) group 2) bleached, laser-treated(BLLA) group 3) non-bleached, acid-treated(NBAC) group and 4) bleached, acid-treated(BLAC) group. Here, $opalescence^{(R)}$ (10% carbamide peroxide) was used for bleaching agent. The treated specimens were observed by confocal laser scanning microscopy and bonded with composite resin for shear bond test. The following results were obtained from this experiment : 1. Compared with the ENB group, the EBL group was shown be dyed about $20{\mu}m$ deeper with rhodamine B. The DBL group appeared to be caved in at the entry part of the dentinal tubules, was dyed about $20{\mu}m$ deeper and $5{\mu}m$ wider in diameter, compared with the DNB group. 2. In comparison with the EBLAC group, the ENBAC group looked evenly bonded with the resin, while the DNBAC group, compared to DBLAC group, was observed to have its resin tags penetrated about $50{\mu}m$ deeper. Other than those, however, no observable differences between ENBLA and EBLLA group or between DNBLA and DBLLA group were found. 3, At the shear bond test, the ENBAC group was shown to have statistically significant higher shear bond strength than the EBLAC group(p<0.05). No statistically significant differences between the ENBLA and the EBLLA groups were observed(p>0.05). 4. At the shear bond test, the DNBAC group was shown to have statistically significant higher shear bond strength than the DBLAC group(p<0.05). No statistically significant differences between the DNBLA and the DBLLA groups were observed(p>0.05). The in vitro observations above suggest that tooth-bleaching procedure brings a certain change on enamel and dentin surfaces and it weakens the shear bond strength with composite resin when the bleached tooth was acid-treated.

• Restorative Dentistry and Endodontics
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• v.39 no.3
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• pp.172-179
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• 2014

Objectives: This study aimed to assess the effect of 38% carbamide peroxide on the microleakage of class V cavities restored with either a silorane-based composite or two methacrylate-based composites. Materials and Methods: A total of 96 class V cavities were prepared on the buccal surface of extracted human teeth with both enamel and dentin margins and were randomly assigned into three groups of Filtek P90 (3M-ESPE) + P90 system adhesive (3M-ESPE)(group A), Filtek Z250 (3M-ESPE) + Adper Prompt L-Pop (3M-ESPE)(group B) and Filtek Z350XT (3M-ESPE) + Adper Prompt L-Pop (group C). Half of the teeth were randomly underwent bleaching (38% carbamide peroxide, Day White, Discus Dental, applying for 15 min, twice a day for 14 day) while the remaining half (control) were not bleached. Dye penetration was measured following immersion in basic fuchsine. Data were statistically analyzed using Kruskal-Wallis and Mann-Whitney U tests at a level of 0.05. Results: No significant differences were found between composites in the control groups in enamel (p = 0.171) or dentin (p = 0.094) margins. After bleaching, microleakage of Z250 (in enamel [p = 0.867] or dentin [p = 0.590] margins) and Z350 (in enamel [p = 0.445] or dentin [p = 0.591]margins) did not change significantly, but the microleakage of P90 significantly increased in both enamel (p = 0.042) and dentin (p = 0.002) margins. Conclusions: No significant differences were noted between the bleached and control subgroups of two methacrylate-based composites in enamel or dentin margins. Microleakage of silorane-based composite significantly increased after bleaching.

• The Journal of the Korea Contents Association
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• v.12 no.1
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• pp.353-360
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• 2012

The purpose of this study was to evaluate tooth color and microhardness after 15% carbamide peroxide(CP) bleaching treatments with/without potassium nitrate and fluoride(PF), which were used home bleaching. Thirty tooth specimens were obtained from thirty premolar and were randomly divided into three groups: 1, untreated controls(Distilled water): 2, treatment with 15% CP bleaching agent; 3, treatment with 15% CP bleaching agent (contained 3% potassium nitrate and 0.11% fluoride). All groups were treated 6h per day for 14 days then immersed in distilled water. Changes in enamel color were evaluated on Baseline and Day 14. Microhardness were evaluated on Baseline, Days 7 and 14. All the bleached enamel specimens revealed increased whiteness without control group. Groups 2 and 3 showed significantly decreased enamel microhardness compared to control group. On Day 7, Groups 2-3 showed significantly decreased enamel microhardness compared to control group and respective baseline data. The percentage microhardness loss(PML) look at Day 7 and 14 for Group 1, respectively, there was little difference between 1.7 and 0.8. However, Group 2 was 21.9 and 3.5, Group 3 was 16.7 and 1.4 as a baseline and Day 7 were significantly different (p<0.05). The PML of group 2 was significantly highest than that of group 3 on Day 7. As a result, the data indicate that the addition of PF did not influence the whitening efficacy of the bleaching agent negatively. PF-containing bleaching agent reduce the percentage microhardness loss. PF-containing tooth bleaching your teeth with a whitening effect can be reduced by decreasing the hardness of enamel.