• Journal of Oral Medicine and Pain
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• v.30 no.4
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• pp.465-473
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• 2005

The purpose of this study was to evaluate the desensitizing effects of a Nd:YAG laser (Sunlase, SUNRISE Technologies, Inc., USA) irradiation on cervically exposed hypersensitive dentine. 45 patients was irradiated with pulsed Nd:YAG laser (1.5 W, 20 Hz, 75 mJ/pulse, 4 minutes) as the experimental group, 27 patients was mock irradiated as the control group. The degree of sensitivity to the thermal and tactile stimuli were determined qualitatively with an evaporative stimulus defined as two times air blast at a distance of 3 mm from each site to be tested and with a mechanical stimulus as a slightly scratching the cervical site with a dental explorer. A qualitative registration of the degree of discomfort was determined according to a numerical pain scale(NPS) in an 11-point scale in which 0= "no pain" and 10="most excruciating pain imaginable". Recordings were assessed before treatment, immediately after, 1 and 2 weeks after treatment. Pain tolerance threshold and pulp vitality were evaluated with electric pulp tester before and immediately after treatment. 1. Desensitizing of hypersensitive dentine with Nd:YAG laser irradiation was more effective than that with mock irradiation. 2. The placebo effect of mock irradiation was recognized for severe sensitive teeth($NPS\;{\geqq}\;6$), but not for moderate sensitive teeth(NPS < 6). 3. Laser irradiation did not affect the pain tolerance threshold and pulp vitality of the hypersensitive teeth. 4. Desensitizing effect of laser irradiation for the hypersensitive teeth had been continuing at least 2 weeks. It was concluded that desensitizing of hypersensitive dentine with a Nd:YAG laser is effective and the maintenance of the positive result was more prolonged than the placebo effect.

• Restorative Dentistry and Endodontics
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• v.24 no.2
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• pp.364-371
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• 1999

본 연구는 테트라싸이클린에 의해 변색된 백서 치아에 대한 3 종 표백제의 표백효과를 비교하고 표백제의 침투 깊이 (법랑질 두께)에 따른 표백효과의 차이를 판별하기 위해 시행되었다. 30 마리의 웅성 백서에 매일 2주 동안 테트라싸이클린 용액을 복강내 주입하였다. 디스크 형태의 32개 백서 치아 표본을 16 시간 동안 자외선으로 조사하여 변색을 야기시켰다. 대조군은 생리 식염수에 보관하였으며 실험군은 3종 표백제(Opalescence, Rembrandt, NiteWhite)에 하루 5회씩 2주간 노출시켰다. 치아 색상을 표백전, 표백 1일, 3일, 5일, 7일, 9일, 11일, 및 14일에 각기 기록하여 치아내 변색부와 정상 색상간의 색상차 (${\Delta}$E)를 판독하였다; 대조군 - 9.78, 9.17, 9.36, 9.65, 9.40, 9.99, 10.57, 11.36; Opalescence - 10.08, 7.63, 6.72, 6.04, 5.10, 4.87, 4.89, 4.27; Rembrandt -9.83, 11.27, 9.55, 8.36, 7.75, 6.94, 7.11, 7.04; NiteWhite - 10.44, 9.92, 7.58, 6.80, 5.45, 5.05, 4.73, 4.01. 표백된 모든 치아들의 색상이 밝아졌다. (p<.01) 테트라싸이클린이 주입된 56개 백서 치아를 3 일간 자외선에 조사한 다음, 3가지 유형의 표백제 침투깊이를 설정하였다. 설측 상아질과 순측 법랑질을 통한 침투 (DN), 순측 법랑질만을 통한 침투 (RE), 1.0 mm 두께의 사람 법랑질로 피개된 순측 법랑질을 통한 침투 (HE). 표본들을 Opalescence로 하루 5회씩 1주일 및 4 주간 표백한 후 횡단하여 치아 색상을 측정하였다. 표백되지 않은 치아들을 대조군으로 이용하였다. 치아내 변색부와 정상 색상간의 색상차 (${\Delta}$E)는 다음과 같았다. 대조군 - 11.67; 1주 DN 군 - 13.55; 1주 RE군 - 12.80; 1 주 HE군 - 12.07; 4주 DN군 - 7.48; 4주 RE군 - 7.50; 4주 HE군 - 11.69. 4주 DN군과 4주 RE군의 색상 변화가 가장 크게 나타났다.(p<.01)

• The korean journal of orthodontics
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• v.38 no.5
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• pp.337-346
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• 2008

Objective: The purpose of this study was to determine whether an exogenous electric current to the alveolar bone surrounding a tooth being orthodontically treated can enhance tooth movement in human and to verify the effect of electric currents on tooth movement in a clinical aspect. Methods: This study was performed on 7 female orthodontic patients. The electric appliance was set in the maxilla to provide a direct electric current of $20{\mu}A$. The maxillary canine on one side was assigned as the experimental side, and the other as control. The experimental canine was provided with orthodontic force and electric current. The control side was given orthodontic force only. Electrical current was applied to experimental canines for 5 hours a day. The amount of canine movement was measured with an electronic caliper every week. Results: The amount of orthodontic tooth movement in the experimental side during 4 weeks was greater by 30% compared to that of the control side. The amount of increase in tooth movement in the experimental side was statistically significant. The amount of tooth movement in the experimental side during the first two weeks was !Bleater than that in the following two weeks. The amount of weekly tooth movement in the control side was decreased gradually. Conclusions: These results suggested that the exogenous electric current from the miniature electric device might accelerate orthodontic tooth movement by one third and have the potential to reduce orthodontic treatment duration.

• 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.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.4
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• pp.405-417
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• 2010

Previous studies have already shown that mouthguard is effective in protecting jaw bone, teeth and oral tissue against sports trauma. However, other than severe trauma, repetitive force, such as disorders like clenching, cause teeth or oral tissue damage. These kinds of disorders usually present pathologic attrition in the posterior teeth, resorption in alveolar bone, loss of teeth and destruction of occlusion. Wearing a mouthguard is believed to be effective in preventing these disorders. But its effect is not examined thoroughly enough. The purpose of this study is to identify whether mouthguard is effective in reducing strain caused by clenching. Mandibular first molars in the normal occlusal relationship without any history of dental treatment were chosen. Biaxial type strain gauge was placed on the buccal surface of the tooth. Having maximum occlusal force, measured by load cell, as a standard, clenching intensity were divided into three stages; moment of slightly tooth contact, medium bite force (50% of maximum bite force), maximum bite force. Strain occurring in dentition in each stage with and without mouthguard was measured. Changes in strain (on dentition) between each stage and difference in strain, between with or without mouthguard were recorded by PCD-300 analyzer and PCD-30 soft ware. The data was statistically analyzed by Wilcoxon signed rank test. The following results were drawn; Without mouthguard, strain given on dentition increased as the clenching force increased. With mouthguard, strain given on dentition also increased as the clenching force increased. With mouthguard, strain decreased, in all cases of clenching force stages. Data on the moment of slightly tooth contact stage, had no statistical significance. However, with mouthguard, 50-90% of decrease in strain could be obtained in maximum occlusal force, compared to the group without mouthguard. Mouthguard decreased the strain on the dentition, caused by clenching. Therefore, mouthguard seems to be effective in preventing damage on dentition, by acting against clenching, which occurs both consciously and unconsciously during sports activities.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.1
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• pp.83-91
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• 2008

Dental caries which is one of the most common chronic disease complexly developed by the action of oral bacteria, diet, and host factor. Various prevention program enhance resistance of demineralization and reduce the acidogenecity of oral bacteria have been introduced, representative material is fluoride and chlorhexidine. The purpose of the study was to evaluate and compare effectiveness of fluoride varnish and chlorhexidine varnish in vivo. Bovine tooth specimens were implanted in the lower space maintainers and applied with fluoride varnish and chlorhexidine varnish. After seven days in oral environment, metal mesh was covered to make similar condition of plaque accumulation and induce caries. All specimens were analysed by EPMA to evaluate quantitative change of Ca, P and by polarized microscope to identify histological changes. The results were as follows : After initial artificial caries induction in the mouth, there were remarkable enamel caries lesion in the control group under polarized light microscopy. The highest amount of mineral decrease were showed in control group. No statistically significant mineral decrease were showed in fluoride varnish group, while chlorhexidine varnish group showed only significant decrease of P(P<0.05). In conclusion both fluoride varnish and chlorhexidine varnish seemed to be effective for protecting enamel surface from caries activity, although fluoride varnish has more anticariogenic effect than chlorhexidine varnish.

• 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.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.41-41
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• 2010

상온에 준하는 저온의 플라즈마를 발생시키는 장치들이 개발되면서, 저온 플라즈마와 생체조직간의 상호작용에 대한 연구가 큰 관심을 끌고 있다. 플라즈마에서 발생되는 다량의 이온과 활성종, 그리고 UV 등이 박테리아나 세포들과 작용함으로 해서 암세포 사멸, 치아 미백, 박테리아 살균/멸균, 지혈등의 효과들이 나타나고 있으며, 이러한 효과들을 극대화할 수 있는 장치 개발과 플라즈마와 생체조직간의 상호작용 메카니즘을 규명하는 것이 중요한 이슈가 되고 있다. 나노 금입자를 암세포의 막단백질인 FAK의 항체와 결합시킨 중합체를 만들어서, 암세포 표면에 나노 금입자붙이고, 플라즈마를 조사했을 때, 나노 금입자가 부착되지 않았을 경우에 비해서, 5배이상 사멸률이 증가하였다.[1] 변색된 치아에 미백제의 주성분인 과산화수소를 도포하고, 10분간 플라즈마를 조사하게 되면, 과산화수소만 도포했을 때에 비해, 치아 표면의 색이 3배이상 밝아지는 것을 관찰할 수 있었다. 과산화수소를 플라즈마에 노출시켰을 때, 활성종인 OH의 생성이 2배이상 증가하였고, 플라즈마에 의한 OH 생성의 촉진이 치아 미백효과가 증대되는 주된 요인인 것으로 추측된다.[2] 플라즈마에서 발생되는 O, $O_3$와 같은 활성종들은 살균력이 뛰어나기 때문에, 저온 플라즈마를 의료기구의 소독/멸균에 응용할 가능성이 아주 크다. 대장균이나 구강 세균이 플라즈마 처리로 5분이내에 멸균되는 것을 확인하였고, 핸드피스와 같은 의료기구를 오염시켜서 멸균 테스트를 수행하고 있다.

• The Journal of the Korea Contents Association
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• v.18 no.5
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• pp.376-385
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• 2018

The purpose of this study was to investigate the effect of mobile task information presentation using 3D multimedia on tooth carving knowledge, performance and class satisfaction for dentistry. To accomplish this purpose, we divided 66 dental students into the two groups: The experimental group was presented with mobile task information using 3D modeling. and the control group was presented task information using textbook. As a result for the study, First, Mobile task information presentation using 3D multimedia in class has significant effect on the tooth carving performance and class satisfaction. Second, tooth morphology knowledge in control group presenting task information using the text book showed relatively higher than in experimental group which presenting mobile task information using the 3D modeling. The conclusion of this study is that the class presenting mobile task information using 3D modeling can be enhances class satisfaction and, teaching and learning strategy to improve tooth carving performance.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.4
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• pp.652-661
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• 2008

The purpose of this study was to evaluate the skeletal and dental effects obtained by the Frankel functional regulator III in growing children with Class III malocclusions. Cephalometric changes in thirty children at the time of mixed dentition malocclusions (initial mean age, $7.9{\pm}1.1$ years; mean treatment duration, $1.5{\pm}0.8$ years) were analysed. The results were as follows : 1. The skeletal effects on the maxilla showed a significant downward displacement whereas forward displacement was not significant in comparison with the control group. 2. The skeletal effects on the mandible showed statistically significant backward and downward displacement. 3. The dental effects showed statistically significant backward movement in the mandibular incisor tip and increase of overjet The results suggested that forward displacement on the maxilla was insufficient and treatment effects were caused mainly by downward displacement of the maxilla, backward and downward rotation of the mandible, and the increase of overjet during short period.