• Journal of the Korea Convergence Society
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• v.6 no.5
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• pp.165-171
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• 2015

This in vitro study compared the effect of bleaching agent modified by the addition of $TiO_2$ catalyst converged bleaching agent. Nonvital teeth samples were assigned to four group(n=6) according to the bleaching agent: 10% carbamide peroxide(CP) bleaching agen, 10% CP with 10% $TiO_2$ catalyst, 20% CP bleaching agent and 20% CP with 20% $TiO_2$ catalyst. Changes in enamel color were evaluated on minutes 30, 60, 180, 300 and 420. It was found that 20% CP with 20% $TiO_2$ catalysis increased the whiteness and overall color value and showed significantly brightened. The teeth bleaching time was reduced with $TiO_2$ catalyst converged bleaching agent. This result will contribute to development of the teeth bleaching agent.

• The Journal of the Korea Contents Association
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• v.10 no.11
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• pp.235-242
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• 2010

The purpose of this study was to evaluate tooth whitening and microhardness after treatments with tooth bleaching agents containing dicalcium phosphate dihydrate (DCPD) and 35% hydrogen peroxide (HP) which were used in-office bleaching. Thirty enamel specimens were obtained from human premolars and randomly divided into 3 groups(n=10). Tooth bleaching agents were prepared with DCPD (0 g for controls, 0.1 g and 1 g for experimental groups) and HP solution (35% HP). All groups were applied to enamel surfaces for 60 min for 1 day. The pH of each tooth bleaching agent was measured. Tooth color, microhardness of enamel surfaces were also measured. The tooth bleaching agents containing DCPD showed a significant increase in pH compared to the ones without DCPD(p<0.05). Paired t-tests showed significant difference in color values of enamel before and after bleaching in all the groups(p<0.05). As a result, changes in color, containing DCPD group does not contain a statistically significant difference between groups was observed.(p>0.05). In all groups, tooth hardness after bleaching showed a significant decrease in microhardness (p<0.05). However, the DCPD concentration increased in the bleaching, microhardness values slightly decreased. Based on the above results, tooth bleaching agents containing DCPD and 35%HP were equally effective. Due to increases in pH and effective reduction of tooth surface decalcification, the surface characteristics are exposed to a reduced degree of negative effects, resulting in fewer constituent enamel alterations. Thus, commercial availability of the constituents of tooth whitening materials can be achieved.

• Journal of dental hygiene science
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• v.6 no.3
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• pp.153-158
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• 2006

Bleaching of vital and nonvital teeth is becoming a more commonly used treatment in the dental office and at home. To improve appearance and remove discoloration, the teeth of specific patients are treated with a variety of bleaching agents. The typical bleaching agents contains carbamide or hydrogen peroxide as the active component. The purpose of the review article was to summarize and discuss the available information concerning the effect of peroxide releasing bleaching agent on dental restorative materials and restorations. Information from all original scientific full papers or reviews listed in PubMed or ISI Web Science were included in the review. Bleaching may exert a negative influence on restorations and restorative materials. Advice is provided based on the current literature to minimize the impact of bleaching treatment on restorative materials and restorations.

• Journal of dental hygiene science
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• v.12 no.4
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• pp.320-328
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• 2012

The purpose of this study was to evaluate the tooth whitening and properties of an enamel surface after treatments with tooth bleaching agents that contained dicalcium phosphate dihydrate (DCPD) and hydrogen peroxide (HP). Thirty specimens were obtained from fifteen premolar and were randomly divided into three groups (n=10): 1, 3.5% HP + 0 g DCPD; 2, 3.5% HP + 0.1 g DCPD; 3. 3.5% HP + 1 g DCPD. All groups were bleached 8 hours per day for 14 days. With increasing DCPD concentration, the pH values in the agents increased, making it less acidic. However, there was no statistically significant difference (p>.05). As the concentration of DCPD was increased, the concentration of Ca and P was also increased. In all groups, after the tooth whitening, the tooth color was found to have a value of $L^*$ (p<.05). All groups showed significantly decreased enamel microhardness compared to their baseline (p<.05). The percentage microhardness loss (PML) of the group A1 and A2 were significantly lower than that of group A3. The obvious variation of morphology was observed on enamel surfaces in group A1. Following an analysis of the constituents of enamel surface after bleaching, as DCPD content was increased, the amount of Ca and P was increased. In this study, the experimental results suggest that DCPD/HP agent less demineralization changes such as the erosion morphology and hardness loss without compromising whitening efficiency.

• Journal of dental hygiene science
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• v.10 no.4
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• pp.295-300
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• 2010

The aim of this study were to elucidate effects of fluoridated bleaching agents and post-treatment fluoride application on the color and microhardness of enamel surface. Twenty freshly extracted human adult molar were each sectioned into halves, the specimens divided and treated according to four experimental groups: 1, untreated controls: 2, treatment with 10% carbamide peroxide (CP) bleaching agent; 3, treatment with 10% CP containing 0.11% fluoride; 4, treatment with 10% CP followed by a 0.9% sodium fluoride gel application. Group 2-4 were compared with the baseline data. treated 8 h per day for 14 days then immersed in distilled water for 2 weeks. Changes in enamel color and microhardness were evaluated on Days 7 and 14. All the bleached enamel specimens revealed increased whiteness and overall color value. Groups 2 and 4 showed significantly decreased enamel microhardness compared to their baseline. The specimens treated with fluoridated bleaching agents showed relatively less reduction in enamel microhardness than those treated with nonfluoridated agents during the bleaching treatment. The addition of fluoride did not impede the tooth whitening. The fluoridated bleaching agents reduced the microhardness loss of enamel.

• 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.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.541-541
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• 2013

현재 병원에서 사용하는 치아미백은 고농도의 과산화수소와 carbamide peroxide가 함유된 미백제를 이용하여 전문성을 가진 의사가 직접 시술을 하고 있다 [1]. 과산화수소의 농도가 높을수록 미백효과가 높지만 [2] 과산화수소의 농도가 지나치게 높으면 인체에 유해하다 [3,4]. 따라서, 고농도의 과산화수소가 함유된 미백제의 사용은 전문가만 시술할 수 있도록 이를 제한하고 있다. 이로 인해, 일반 가정용으로 판매되는 다양한 미백제품들은 저농도(최대6%)의 과산화수소가 함유되어 있으며 장기간 지속적으로 사용해야만 치아미백효과를 볼 수 있다. 우리는 가정에서도 보다 안전하고 단기간에 효율적으로 치아의 미백효과를 보기 위하여, 식품의약품안정청에서 규제하고 있는, carbamide peroxide (15%)와 저온 대기압 플라즈마 제트를 사용하여 미백효과를 관찰하였다. 플라즈마 제트의 유량은 200 sccm이며, 공기를 사용하였다. 미백효과를 보기 위한 대상으로는 우치(牛齒)를 사용하였으며, 플라즈마를 처리하여 미백효과를 관찰하였다. 실험 대조시료군으로는 carbamide peroxide (15%)를 처리하지 않은 우치와 처리한 우치, 그리고 carbamide peroxide (15%)를 처리한 우치에 수증기(0.2~1%)를 첨가한 다음, 이들 세가지 시료에 각각 공기 플라즈마를 조사하여 비교해보았다. 모든 실험의 플라즈마 처리시간은 최대 20분까지로 하였다. 수증기를 첨가한 이유는 활성산소의 농도를 높이기 위함이며, 이로써 탁월한 미백효과를 얻을 수 있다. 이는 활성산소와 치아의 유기질이 반응하여, 색이 진한 탄소고리 화합물을 밝은 색의 사슬구조로 바꿔주기 때문이다. 실험을 통하여 우치에 carbamide peroxide (15%)와 수증기(0.2~1%)를 처리한 경우 플라즈마의 미백효과가 탁월함을 보였다. 이때 CIE색좌표 ($L^*a^*b^*$)에서 명도도가 최대 2배 이상 높아짐을 보았다. 미백효과에 대한 측정은 측색분광기(CM-3500d)를 이용하였다.

• Journal of dental hygiene science
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• v.10 no.2
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• pp.95-100
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• 2010

The purposes of this study were to examine the effect of different fluoridated bleaching solution on the changes in physical and chemical characteristics of tooth. Forty-eight bovine incisors were divided into four groups to receive bleaching treatments, over a 14days period, as follows: no treatment; 10% carbamide peroxide (CP) bleaching; 10% CP containing 0.05% fluoride; and 10% CP containing 0.1% fluoride. All the specimens were highly polished and discolored with commercial COCK.Color and enamel changes were determined with colorimeter, microhardness tester, scanning electron microscope, atomic force microscopy. All the collected data were analyzed with one-way ANOVA. After the bleaching, bleached groups showed the color change(E*). Microhardness of 10% CP group decreased after tooth bleaching. But microhardness of containing fluoride bleached groups increased after tooth bleaching. Enamel surface of 10% CP bleached group showed any apparent morphology and roughness changes compared to the enamel which was stored in distilled water only. These results demonstrated that Fluoridated 10% Carbamide Peroxide have appreciable bleaching effect on bovine teeth and were not adversely affects enamel. Supporting influence of fluoride-containing bleaching solution on remineralization could be observed and further research must be carried out in various active environments to confirm these results clinically.

• Journal of dental hygiene science
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• v.13 no.1
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• pp.13-19
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• 2013

This study evaluated the change of color and the microhardness according to time-out using the office bleaching with in vitro test after bleaching one time 1 day per week, total three times, for the control group and three times per 1day for the experimental group. $L^*$ was increased in both groups. Group 1 showed a significant increase statistically between before and after tooth whitening (p<0.05). Group 2 showed a significant increase statistically between before and after tooth whitening (p<0.05). ${\Delta}E^*$ was huge in both groups. In group 1, it was great in terms of statistical significance between 1 day and 7 days after tooth whitening (p<0.05). In group 2, it was the greatest between before and 1 day after tooth whitening and was significant statistically as well (p<0.05). Vickers hardness number (VHN) decreased in both groups. In group 1, VHN decreased over time and the difference was significant statistically (p<0.05). In group 2, VHN decreased over time and the difference was significant statistically (p<0.05). Percentage microhardness loss was great in both groups. In group 1, it was the greatest between 1 day and 7 days after the treatment, and it was significant statistically (p<0.05). In group 2, it was the greatest between before and 1 day after the treatment, and it was significant statistically (p<0.05). Put together, the more frequent tooth whitening a day is, the longer the period of tooth whitening when applying the same frequency, the greater color change was, however the microhardness decreased, in regard to the results over time using 15% hydrogen peroxide tooth whitening product for professionals.

• 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.