• 치과방사선
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• 제24권1호
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• pp.85-94
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• 1994

The purposes of this study were clinical comparison and evaluation between digital radiography and conventional radiography for the detection of artificial interproximal caries. Four freshly extracted, unrestored posterior teeth were obtained and caries was simulated by drilling semicircled defects with variable size at the interproximal surface of each tooth. The experiments were performed with IBM-PC/32 bit-DX compatible, video camera(VM-S8200, Hitachi Co., Japan), and color monitor(Multisync 3D, NEC, Japan). Sylvia Image Capture Board for the ADC(analog to digital converter) was used, and spatial resolution was 512 × 480 with 256 gray levels. The obtained results were as follows: 1. At the condition of under exposure, the radiographs were superior to the digital images in readability. Also, as the size of the artificial lesion was increased, readability of the radiographs was elevated. 2. The digital images were superior to the radiographs in readability especially under over exsposure. 3. As the exposure time and size of lesion was increased, the gray level of region of interest of the digital image was decreased proportionally. 4. As the F-value of average gray level of region of interest at individual exposure time and size of lesion, gray level of the all lesion sizes was decreased in comparison with that of the normal enamel.

• 치위생과학회지
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• 제20권4호
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• pp.252-260
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• 2020

Background: In this study, the bleaching effect and surface damage of two types of over-the-counter home tooth bleaching agents were explored using an in vitro study of bleaching agents applied to bovine teeth specimens for 14 days. Methods: Domestic over-the-counter home tooth bleaching agents of gel and patch form that shared common active ingredients and manufacturers were selected and tested. The experiment specimens were made using composite resin with bovine tooth samples and then measured the initial microhardness. Specimens were then divided into a Gel group and a Patch group and underwent bleaching treatment once a day for two weeks for 30 to 60 minutes (recommended) or 7 hours. All specimens were coffee-stained prior to bleaching. The bleaching effect was measured using a spectrophotometer and surface damage was measured using a microhardness meter. Results: The difference in color following the bleaching procedure was positive in both the Gel and Patch group, although there were no statistically significant differences in bleaching effect between groups. There was no significant difference in bleaching effect based on duration. The microhardness test revealed that both the Gel group and the Patch group had surface damage after bleaching. The greatest surface damage was found in the Patch group that had undergone a 7-hour bleaching treatment, although the differences were not statistically significant. Conclusion: The bleaching effect of the home tooth bleaching agent was visible to the naked eye. However, longer applications than recommended did not result in greater bleaching, unlike consumers' expectations, and instead increased the chance of enamel damage. As such, there is a need for consumers to be alert and adhere to recommendations provided by each company.

• 대한소아치과학회지
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• 제44권3호
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• pp.378-383
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• 2017

치아 변색을 일으키는 다양한 원인들이 있다. 혈중 빌리루빈의 증가도 치아변색을 일으킬 수 있는데 이는 드문 경우이나, 대부분 초록색 변색이 보고 되었다. 본 증례는 신생아 고빌리루빈혈증 병력이 있는 환아의 유치의 초록색 변색에 대한 것이다. 16개월, 22개월 두 남아가 맹출한 치아의 비정상적인 색을 주소로 내원하였다. 두 환아의 유치는 법랑질저형성증을 수반한 초록색 변색을 보였다. 두 환아 모두 저체중, 조산아였으며, 신생아 고빌리루빈혈증을 진단받았다. 전신적인 질환은 치아의 형성시기에 경조직에 영향을 줄 수 있으며, 변색도 일으킬 수 있다. 정상적인 치아 발육과 환아의 심미적 요구를 충족시키기 위해 정기적인 관찰이 필요하다. 소아치과의사는 유치열기의 변색을 먼저 관찰 할 수 있다. 이와 같은 증례들을 통해 치과의사는 치아변색에 대해 전신적 질환을 추론할 수 있다.

• 한국융합학회논문지
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• 제8권9호
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• pp.127-133
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• 2017

본 연구의 목적은 현대사회에서 치아미백에 대한 관심도가 높아짐에 따라 실생활에서 쉽게 접할 수 있는 과일들을 이용한 천연 치아미백술 효과를 확인하기 위함이다. 20개의 소구치를 4개씩 5 그룹으로 딸기(A), 레몬(B), 바나나 껍질(C), 베이킹소다(D), 미백치약(E)을 법랑질 표면에 칫솔을 이용하여 처리하였다. 치아의 표면에 아침, 점심, 저녁 3분씩 동일한 시간에 칫솔을 이용하여 처리 후 멸균증류수로 세척하고 생리식염수에 담가 보관하였다. 이러한 과정을 총 4주 동안 반복하였으며, 1주 간격으로 치아의 색변화를 관찰하였다. 4주간 치아에 적용한 결과, 3주후부터 치아의 색 변화에 유의한 차이를 보였다(p<0.05). 그 중에서도 딸기와 레몬은 미백치약보다 높은 색의 변화를 보였으며, 이는 딸기와 레몬은 미백치약보다 높은 미백효과를 가져다주며 미백치약에 함유된 인체에 유해할 수 있는 화학성분을 대신하여 딸기와 레몬을 사용해 보다 안전한 천연미백술로 미백 효과를 거둘 수 있을 것으로 사료된다.

• Restorative Dentistry and Endodontics
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• 제28권5호
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• pp.402-408
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• 2003

This study was done to present a criterion in selection of the most proper light sources and materials by measuring metamerism index(MI) of the light curing composite resins with spectrocolorimeter. Metamerism is defined when two objects appear to be the same color in one illuminant but different in another. This is due to the fact that they have different spectral curves that fail to match under the second illuminant. In this study, A1 & A3 shade of five light curing composite resins (Esthet-X, Filteck Z250, Filteck A110. Charisma. Vitalescence) were chosen based on Vita shade. Five samples were made for shade of each product with Teflon mold (diameter: 15mm, thickness: 2mm). Metamerism index of each samples on a Barium sulfate plate($L^{*}=96.54,{\;}a^{*}=0.19,{\;}b^{*}=0.01$) prepared for sample fixation were measured with spectrocolorimeter(Miniscan XE plus. Model 4000s. Hunter Lab. USA) by applying standard light source D^{65}, C. Fcw, TL84 and A. Standardization was done with reference standard(X=80.8, Y=85.7, Z=90.8) and light trap. The results were as follows. 1. Different resins with same Vita shade showed recognizable color difference (${\delta}E^{*}>2$). 2. All composites had MI below accepted value 0.5 between standard illuminant(D$_{65}$, C, & A) and below 1.5 under fluorescent condition (Fcw & TL84). 3. MI value between $D^{65}$ and A showed higher value than MI value between other source of light(p<0.01). 4. All resins except Z250 showed MI value that A3 is higher than A1 between $D^{65}$ and A(p<0.05).except Z250 showed MI value that A3 is higher than A1 between $D^{65}$ and A(p<0.05).

• 대한소아치과학회지
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• 제37권4호
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• pp.532-536
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• 2010

Hidden caries는 임상 검사상 교합면이 매우 건전하거나 소량의 탈회만이 관찰되지만 방사선 사진 상에서 상당 수준 진행된 상아질 우식이 발견되는 경우를 일컬으며 Covert caries, Occult caries, Fluoride syndrome 등이 동의어로 사용되고 있다. 발생 원인으로는 불소의 영향, 세균의 종류 및 세균 영양분 공급 경로의 차이, 열구 기저면으로부터 시작된 우식증, 맹출 전우식증 등의 주장들이 제기되고 있지만 현재 정확한 원인은 밝혀지고 있지 않다. 본 증례는 임상 및 방사선 사진 검사에서 Hidden caries를 발견한 두 환아들의 치험례로 두 증례 모두에서 깊은 상아질 우식을 보여 각각 치근단 형성술과 간접치수복조술을 시행하였다. 교합면이 비교적 건전해 보이는 특징 뿐만 아니라 Hidden caries의 우식 상아질은 임상적으로 관찰 가능한 우식에서 채취한 우식 상아질에 비해 밝은 색을 띄는 특징이 있어 시진으로 관찰하기 더욱 어려운 것으로 생각된다. 따라서 본 증례와 같이 진행된 우식병소로 인해 임상증상이 발현된 후에야 이를 발견하게 되는 경우가 많으므로 정기적인 방사선 검사와 함께 Diagnodent.. 등과 같은 최신의 우식 진단도구들의 사용으로 우식병소의 조기진단을 위해 노력해야 할 것으로 생각된다.

• Restorative Dentistry and Endodontics
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• 제25권2호
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• pp.243-253
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• 2000

The purpose of this in vitro study was to evaluate dentin bonding by two different dentin bonding systems(DBS) using acetone based primer or adhesive [All Bond 2(AB2), One Step(OS)] when they were applied by wet or dry bonding technique. Morphology of resin-dentin interface and hybrid layer thickness(HLT) were investigated using Confocal Laser Scanning Microscope(CLSM) and compared to shear bond strength(SBS). 72 extracted sound human molars were randomly divided into 4 groups of 18 teeth each - Group 1.(AW); AB2 by wet bonding. Group 2(AD); AB2 by dry bonding. Group 3.(OW); OS by wet bonding, Group 4.(OD); OS by dry bonding. In 6 teeth of each group, notch-shaped class V cavities(depth 2mm) were prepared on buccal and lingual surface at the cementoenamel juction(12 cavities per group). To obtain color contrast in CLSM observation, bonding resins of each DBS were mixed with rhodamine B and primer of AB2 was mixed with sodium fluorescein. Prepared teeth of each group were treated with AB2, OS, respectively according to the manufacturer's instructions except for dentin surface moisture treatment after acid etching. In group 1 and 3, after acid etching, excess water was removed with wet tissue(Kimwipes), leaving consistently shiny, visibly hydrated dentin surface. In group 2 and 4, dentin surface was dried for 10 seconds at 1 inch distance. The treated teeth were then packed with composite resin(${\AE}$litefil) and light-cured. 12 microscopic samples($60{\sim}80{\mu}m$ thickness) of each group were obtained after longitudinal section and grinding(Exakt cutting and grinding system). Morphological investigation of resin-dentin interface and HLT measurement using CLSM were done. For measurement of SBS, remaining 12 teeth of each group were flattened occlusally to remove all enamel and grinded to 500 grit SiC(Pedemet Specimen Preparation Equipment). After applying DBS on the exposed dentin surface, composite resin was applied in the shape of cylinder, which has 5mm diameter, 1.5mm thickness, and light cured. SBS was measured using Instron with a crosshead speed of 0.5mm/min. It was concluded as follows, 1. HLT of AW(mean: $2.59{\mu}m$) was thicker than any other group, and followed by AD, OW, OD in descending order(mean; 2.37, 2.28, $1.92{\mu}m$). Only OD had statistically significant differences(p<0.05) to AW and AD. 2. There were intimate contact of resin and dentin at the interface in wet bonding groups, but gaps or irregular interfaces were observed in dry bonding groups. 3. The length, diameter, density of resin tags were various even in the same group without significant differences between groups and lots of adhesive lateral branches were observed. 4. There were no statistically significant difference of SBS between AB2 and OS, but SBS of wet bonding groups were significantly higher(p<0.05) than dry bonding groups. 5. There were no consistent relationships between HLT and SBS.