• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.3
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• pp.528-537
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• 1999

The purpose of this study was to analyze and compare the bond strengths between stainless steel plate and zinc phosphate cement, polycarboxylate cement and glass ionomer cement, which are frequently used for cementation of stainless steel crowns. Three cementing materials were glued to the poles standing above stainless steel plate, bovine teeth, light cured glass ionomer restorative material and amalgam. And the tensile bond strengths between them were measured with universal testing machine and the results were statistically processed using ANOVA and Student t-test. The obtained results were as follows : 1. On stainless steel plate, glass ionomer cement and polycarboxylate cement showed higher tensile bond strengths compared to zinc phosphate cement, with no significant difference between the former two. 2. On the surface of bovine teeth and glass ionomer restorative material, glass ionomer cement showed highest bond strength, followed by polycarboxylate cement and zinc phosphate cement in order. 3. For amalgam restoration, polycarboxylate cement and glass ionomer cement showed higher tensile bond strengths than zinc phosphate cement, with no significant difference between the former two.

• Journal of Oral Medicine and Pain
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• v.20 no.2
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• pp.429-447
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• 1995

This study was designed to determine the most effective concentration of fluoride and levels of laser irradiation for the remineralization of decayed teeth. After irradiation with a pulsed Nd:YAG laser and the topical application of fluoride, phosphate and fluoride concentration in enamel were measured. And then the changes on surface enamel using an scanning electron microscope were observed. Samples by extraction healthy, permanent, mandibular bovine teeth with no caries were obtained. Among them 371 healthy samples were selected and artificial carious lesions were made. 20 samples were assigned to each experimental group. After irradiation with a pulsed Nd:YAG laser with total energy densities of 10J/$\textrm{cm}^2$, 20J/$\textrm{cm}^2$ for each group. On the teeth, 2% NaF, 1.9% NH4F, 1.6% TiF4 Elmex gel(amine fluoride) and 1.23% APF gel were applied. After pH circulatory procedures, concentrations of fluoride with and Ionalyzer (Orion Research, Model 901, USA) and phosphates with an Uv/V is spectrophotometer (Uvikon 860, Kontrom Co, Switzerland) were measured. By etching the teeth in layers and measuring fluoride concentrations, a profile of fluoride penetration according to depth could be developed. And also the changes on the surface of the enamel using an electron scanning microscope were observed. The comparative analysis yielded the following results : 1. Phosphate concentration was low in all groups compared with the control group except for teeth treated Elmex gel, irradiated with 10J/$\textrm{cm}^2$ and 30J/$\textrm{cm}^2$ energy densities. Teeth treated with APF gel and 30J/$\textrm{cm}^2$ irradiation gad the lowest phosphate concentration. 2. Among all groups, fluoride concentrations in tooth enamel were highest in APF gel and NaF groups irradiated at 30J/$\textrm{cm}^2$. The APF gel group had the highest fluoride concentrations across all energy densities. 3. In the APF gel group, and the NaF group, the greater the energy density of the laser, the higher the fluoride concentrations in the enamel. 4. In all groups, the concentration of fluoride in the enamel by depth tended to decrease with depth. 5. Under the scanning electron microscope, under the condition of irradiation with 20J/$\textrm{cm}^2$, enamel crack was detected for the first time. In the NH4F group, spherical deposits were found on the surface of the enamel, and in the TiF4 group the surface of enamel was covered with an irregular, thin membranous mass in places. In the APF gel and NaF groups irradiated with 10J/$\textrm{cm}^2$, spherical and irregular particles covered the teeth. When these groups were irradiated at 20J/cm2, they were covered with amorphous crystals. These results suggest that one could obtain more effective anticariogenic effects without damage to teeth when less than 20J/$\textrm{cm}^2$ energy densities and APF gel are used.

• The korean journal of orthodontics
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• v.23 no.1 s.40
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• pp.75-88
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• 1993

Recent reports indicate that shorter etching times than 60 seconds can be adopted without affecting the bond strength and clinical disadvantages. The purpose of this in vitro study was to compare the shear bone strength and to measure depth of etch at different etching time length. One hundred and eight extracted bovine lower central incisors were embedded each in a tooth cup with cold-cure acrylic resin. The facial surfaces of the teeth were ground wet with 600-, 800-, 1000-, and 1200-grit Sic papers, and finally polished with a water slurry of extrafine silicon carbide powder, washed with tap water, and dried with hot air. Nine groups of nine prepared teeth were etched with a commercial($38\%$ phosphoric acid solution) for 0, 5, 10, 15, 20, 30, 60, 90, and 120 seconds, respectively, rinsed with tap water, and dried with hot air. One conditioned teeth from every group was selected randomly for the scanning electron microscopic examination, and the remaining eight teeth of the groups were used for measuring the push shear bond strength after bonding brackets and immensing them in the $36.5^{\circ}C$ water for 24 hours. Another nine groups of three teeth were used for measuring the depth of etch and surface roughness with a surface profilometer. after pieces of adhesive tape of 3mm inner diameter positioned on the ground enamel surfaces, and etched with the above mentioned. The data obtained form the above expeiments were analysed statistically with one way ANOVA and Dunkan's multiple range test with the $95\%$ confidence level. The results and conclusion of the study were as follows; 1. The results of shear bond strength for the given experimental etching times were not statistically different, but showed the tendency of decreasing shear bone strength after over 60 seconds etching times. 2. On the scanning election microscopic examination, it was observed that the morphological patterns of etched enamel surface for 5 to 20 seconds were similar and consitent, and those for 30 to 120 seconds showed increasing over-etched patterns depending on the length of etching times. 3. The depth of etch was increased almost proportionally by the length of etching times, but it was not associated with the shear bond strength. 4. The surface roughness increased depending on the length of etching times, but it was not associated with the shear bond strength. 5. This experiment indicated that proper etching time with $38\%$ phosphoric acid solution is in the range of 5 to 30 seconds.

• Journal of dental hygiene science
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• v.23 no.3
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• pp.236-244
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• 2023

Background: The size of the tooth whitening market and toothpaste market is increasing worldwide. The purpose of this in vitro study is to confirm and compare the coffee stain removal effects of commercial whitening toothpaste in sound and demineralized teeth, respectively. Methods: A total of 112 flat permanent bovine teeth specimens were manufactured. Half of the surface of the specimen was coated with an acid-resistant varnish and deposited in an artificial demineralizing solution for 65 hours. The varnish applied to half of the specimen was removed and deposited in a coffee solution for 96 hours to induce coloring. Two control and five experimental group toothpastes for teeth whitening were selected and the main components were investigated. Toothbrushing was performed 50, 100, and 150 times for each toothpaste group. A total of four images were obtained: before the start and after 50, 100, and 150 times of brushing to obtain the lightness (L^*) values of the sound and the demineralized tooth surfaces. The difference in the average value between toothpaste groups at each treatment period was analyzed by one-way ANOVA. The difference in the L^* average value according to the number of the brushing was analyzed by repeated measure ANOVA. Results: All toothpastes in the seven groups contained abrasive agents and had different ingredients for each product. Compared to before brushing, the L^* value changed significantly in all toothpaste groups after brushing 50 times (p<0.05). This was common in both the sound and demineralized teeth surfaces. Demineralized teeth had significantly lower L^* values at all brushing times than that in sound teeth (p<0.05). Conclusion: The effect of whitening teeth was different for each toothpaste. Demineralized teeth were more likely to cause coloration than sound teeth, and the coloration was not removed well.

• Journal of the korean academy of Pediatric Dentistry
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• v.51 no.2
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• pp.165-175
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• 2024

This study aimed to investigate the effects of blood contamination on the Vickers hardness and the surface morphology of premixed MTA and compare them with the effects on conventional MTA. The Vickers microhardness of Endocem MTA Premixed Regular (EP) and ProRoot MTA (PM) was assessed after immersion in fetal bovine serum (FBS) and saline. Stem cells from human exfoliated deciduous teeth (SHED) were seeded on MTA after immersion in FBS, saline, and deionized water (DW). Cell adhesion patterns and surface morphology were visualized via scanning electron microscopy (SEM). The surface microhardness of EP and PM in FBS was lower than in saline. However, short-term exposure of PM to FBS did not reduce the microhardness compared to saline. Angular crystals formed in water, while rounded crystals with more air voids appeared in FBS. Favorable SHED attachment occurred in all groups. Overall, the surface hardness of EP and PM decreased after FBS exposure, although PM was less influenced. We suggest minimizing the amount of bleeding when using MTA clinically; nevertheless, PM remains an option with more expected blood contamination than EP. In summary, exposure to FBS decreased mechanical performance but allowed cell adhesion for both MTAs, with PM being more resistant to these changes.

• Journal of the korean academy of Pediatric Dentistry
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• v.41 no.3
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• pp.233-240
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• 2014

An in vitro study on cariogenic potential of four over-the-counter nutritional supplements for children was performed. The experimental groups were four over-the-counter nutritional supplements. The positive control group was 10% sucrose solution (S), and the negative control group was artificial saliva (T). The pH of each group, the buffering capacities, acid production, the microhardness changes of the bovine teeth specimens were measured. The pH of all experimental groups were lower than critical pH 5.5 where enamel demineralization starts. The buffering capacity of the Hama Vitamin Pharm (Hamsoa Pharm Co., Korea) was highest, and the Smart Chewable Vitamin A (JW Pharm Co., Korea) had the lowest buffering capacity. The reduction rates of the pH of the experimental groups were significantly higher than that of the negative control group (p < 0.05). The microhardness of enamel of all experimental groups and the positive control group significantly decreased. In contrast, the microhardness of enamel of the negative control group significantly increased after experiment (p < 0.05). The reduction rate of the microhardness of enamel of the Hama Vitamin Pharm (Hamsoa Pharm Co., Korea) was significantly higher and Hikid Plus (Sanga Pharm Co., Korea) was significantly lower than the other experimental groups.

• Journal of dental hygiene science
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• v.21 no.2
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• pp.96-103
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• 2021

Background: We aimed to investigate the effect of Citrous limon extract (CLE) on oxidative stress-induced cytotoxicity and nitric oxide (NO) generation and the tooth bleaching effect of CLE as a substitute for hydrogen peroxide (H₂O₂) and determine the feasibility and application of CLE as a safe and effective natural tooth bleaching agent. Methods: The protective effect of CLE on H₂O₂-induced cytotoxicity in Raw264.7 macrophages was investigated by the MTT assay. The inhibitory effect of CLE on the generation of H₂O₂-induced NO was confirmed by the NO assay, and the changes in inducible nitric oxide synthase (iNOS) protein expression were confirmed by western blotting. Stained bovine teeth were treated with/without 15% and/or 35% CLE and H₂O₂, 15% sodium bicarbonate (NaHCO₃) for 3 hours, and were irradiated with/without bleaching light (BL) for 15 minutes. The color change of the treated bovine tooth surface was measured using a colorimeter. Results: The viability of Raw264.7 cells treated with each concentration of CLE and 500 μM H₂O₂ significantly increased as CLE increased, and NO generation and iNOS protein expression were significantly reduced in cells treated with 300 ㎍ CLE+/500 μM H₂O₂+ and 300 ㎍ CLE+/500 μM H₂O₂+/150 ㎍ NaHCO₃+. The bleaching effect of 35% CLE+ was higher than that of 15% CLE+ and 15% NaHCO₃+, and the effect was similar to that of 15% H₂O₂+. The 35% CLE+/15% NaHCO₃+ showed the greatest bleaching effect and was higher than that of the groups irradiated with the BL. The greatest bleaching effect was observed with 35% CLE+/15% NaHCO₃+, followed by 35% H₂O₂+/BL+. Conclusion: CLE inhibited oxidative stress-induced cytotoxicity and NO generation in Raw264.7 cells and, could replace H₂O₂, which causes side effects and risks in teeth breaching treatment. It showed greatest teeth bleaching effect when combined with NaHCO₃. CLE is an effective and safe natural tooth bleaching substitute.

• Journal of dental hygiene science
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• v.23 no.1
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• pp.20-28
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• 2023

Background: This study aimed to determine the effect of ramen sauce on tooth tone changes over time, after selecting three different ramen colors from the ramens sold in the market, and applying the sauce to bovine teeth. Methods: Healthy bovine teeth were selected, and cutting discs were used to produce 60 specimens (5× 5× 3 mm), with 15 specimens distributed per county. Three types of ramen (buldak, chacharoni black bean sauce, and ottogi curry noodle) were used as the experimental group, and water was used as the negative control group. Tooth tone measurement was performed using a spectrophotometer (CM-700d) to measure the color before and after 1 (3 h 44 min), 2 (7 h 28 min), 3 (11 h 12 min), and 4 weeks (14 h 56 min). Analysis of the color tone change was performed using Statistical Package for the Social Sciences version 28. Results: In the experimental group, there was a significant color tone change before and after immersion. L^* indicated the largest change in black bean sauce ramen, a^* indicated buldak ramen, and b^* indicated the largest change in curry ramen. The amount of color change (∆E^*) was the largest in curry ramen, followed by buldak and black bean sauce ramens. The results of the post-hoc analysis showed significant differences between all groups except buldak and black bean sauce ramens. Conclusion: All three types of ramen revealed significant color change before and after immersion, and curry ramen showed the largest amount of color change among them.

• Journal of Periodontal and Implant Science
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• v.39 no.1
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• pp.95-102
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• 2009

Purpose: The aim of this report is to investigate the efficacy of anorganic bovine bone xenograft(Bio-$Oss^{(R)}$) at maxillary sinus floor augmentation. Materials and methods: Two male patients who missed maxillary posterior teeth were included. They were performed maxillary sinus floor augmentation using anorganic bovine bone xenograft(Bio-$Oss^{(R)}$). After 10 or 13 months, the regenerated tissues were harvested using trephine drills with 2 or 4mm diameter and non-decalcified specimens were made. The specimens were examined histologically and histomorphometrically to investigate graft resorption and new bone formation. Results: Newly formed bone was in contact with Bio-$Oss^{(R)}$ particles directly without any gap between the bone and the particles. The proportions of newly formed bone were $23.4{\sim}25.3%$ in patient 1(Pt.1) and 28.8% in patient 2(Pt.2). And the proportions of remained Bio-$Oss^{(R)}$ were $29.7{\sim}30.2%$ in Pt.1 and 29.2% in Pt.2. The fixtures installed at augmented area showed good stability and the augmented bone height was maintained well. Conclusion: Anorganic bovine bone xenograft(Bio-$Oss^{(R)}$) has high osteoconductivity and helps new bone formation, so that it can be used in maxillary sinus floor augmentation.

• The Journal of the Korean dental association
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• v.56 no.4
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• pp.208-216
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• 2018

Patients with malocclusion may present with preexisting mucogingival problems susceptible to attachment loss during or after orthodontic treatment. Lower anterior teeth especially show a high prevalence of gingival recession following orthodontic treatment. This case report demonstrates hard tissue augmentation of labially thin or deficient alveolar bone (dehiscences and fenestrations) to prevent attachment loss during or after orthodontic treatment. Three patients presented clinically prominent root surfaces and dehiscences and fenestrations on cone-beam computed tomography (CBCT) in lower anterior teeth. Labial hard tissue augmentation of lower anterior teeth was performed with deproteinized bovine bone mineral and collagen membrane. Six months later, hard tissue augmentation reduced root prominence and created a greater volume of hard tissue on lower anterior area in clinical and radiographic findings. Hard tissue augmentation using xenograft could prevent attachment loss associated with orthodontic treatment and maintain stability of healthy periodontium.