• Imaging Science in Dentistry
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• 제39권1호
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• pp.35-39
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• 2009

Purpose: The purpose of the experiment was to evaluating the diagnostic ability of dental caries detection using digital subtraction in the artificial caries activity model. Materials and Methods: Digital radiographies of five teeth with 8 proximal surfaces were obtained by CCD sensor (Kodak RVG 6100 using a size #2). The digital radiographic images and subtraction images from artificial proximal caries were examined and interpreted. In this study, we proposed novel caries detection method which could diagnose the dental proximal caries from single digital radiographic image. Results: In artificial caries activity model, the range of lesional depth was $572-1,374{\mu}m$ and the range of lesional area was $36.95-138.52mm^2$. The lesional depth and the area were significantly increased with demineralization time (p<0.001). Furthermore, the proximal caries detection using digital subtraction radiography showed high detection rate compared to the proximal caries examination using simple digital radiograph. Conclusion: The results demonstrated that the digital subtraction radiography from single radiographic image of artificial caries was highly efficient in the detection of dental caries compared to the data from simple digital radiograph.

• Restorative Dentistry and Endodontics
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• 제41권4호
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• pp.255-261
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• 2016

Objectives: This study aimed to analyze the mineral composition of naturally- and artificially-produced caries-affected root dentin and to determine the elemental incorporation of resin-modified glass ionomer (RMGI) into the demineralized dentin. Materials and Methods: Box-formed cavities were prepared on buccal and lingual root surfaces of sound human premolars (n = 15). One cavity was exposed to a microbial caries model using a strain of Streptococcus mutans. The other cavity was subjected to a chemical model under pH cycling. Premolars and molars with root surface caries were used as a natural caries model (n = 15). Outer caries lesion was removed using a carbide bur and a hand excavator under a dyeing technique and restored with RMGI (FujiII LC, GC Corp.). The weight percentages of calcium (Ca), phosphate (P), and strontium (Sr) and the widths of demineralized dentin were determined by electron probe microanalysis and compared among the groups using ANOVA and Tukey test (p < 0.05). Results: There was a pattern of demineralization in all models, as visualized with scanning electron microscopy. Artificial models induced greater losses of Ca and P and larger widths of demineralized dentin than did a natural caries model (p < 0.05). Sr was diffused into the demineralized dentin layer from RMGI. Conclusions: Both microbial and chemical caries models produced similar patterns of mineral composition on the caries-affected dentin. However, the artificial lesions had a relatively larger extent of demineralization than did the natural lesions. RMGI was incorporated into the superficial layer of the caries-affected dentin.

• Restorative Dentistry and Endodontics
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• 제21권2호
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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.

• Imaging Science in Dentistry
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• 제33권2호
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• pp.91-95
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• 2003

Purpose : To compare the diagnostic accuracy of proximal caries detection between Kodak Insight film and the Biomedisys CDX2000HQ digital (CCD) sensor. Materials and Methods: 156 proximal surfaces of extracted teeth, 78 of which had chemical artificial caries, were used in this study. Four observers interpreted the radiographs using a five-point confidence rating scale to record their diagnoses. The results were analyzed by receiver operating characteristic curves, ANOVA and Kappa values. Result: Analysis using receiver operating characteristic curves revealed the areas under each curve which indicated a diagnostic accuracy of 0.951 in Insight and 0.952 in CDX2000HQ digital sensor. ANOVA revealed no significant differences between the two images with respect to caries detection. Kappa values indicated that the mean intra-observer agreement was 0.85 and inter-observer agreement 0.71 in conventional radiography. In digital radiography, the mean intra-observer agreement was 0.84 and inter-observer agreement 0.72. Conclusion: The results suggest that no significant difference exists between the two modalities for artificial caries detection and that CDX2000HQ was as good as Insight film for this purpose.

• 치위생과학회지
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• 제13권4호
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• pp.461-470
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• 2013

정상법랑질과 인공우식법랑질에서 불소바니쉬 도포 후의 항우식 효과를 알아보기 위하여 건전한 소의 전치를 사용하였고, 네 군으로 분류하여 실험하였다. 법랑질 표면의 재광화 및 탈회 후 결정구조의 변화를 FE-SEM으로 관찰하였고, Ca과 P의 정량적 분석은 EDS를 사용하여 측정하였다. 그 결과 불소바니쉬 도포한 경우, 재석회화로 인하여 불규칙하고 매우 거친 표면과 다공성의 구조물이 평활하고 균일한 양상으로 나타났으며, Ca 및 P의 함량이 증가되어 정상법랑질과 인공우식법랑질의 항우식 효과를 크게 증진시키는 것으로 확인되었다.

• 치과방사선
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• 제24권2호
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• pp.439-450
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• 1994

Recently, the digital image was introduced into radiological image. The digital image has the power of contrast enhancement, histogram control, and other digitally enhancement. At the point of the resolution, periapical radiograph is superior to the digital image, but enhanced digital procedure improves the diagnostic ability of the digital image. The purpose of this study was to evaluate the diagnostic ability of artificial proximal caries in conventional radiographs, digital radiographs and enhanced digital radiographs (histogram specification). ROC (Receiver Operating Characteristic) analysis and paired t-test were used for the evaluation of detectability, and following results were acquired: 1. The mean ROC area of conventional radiographs was 0.9274. 2. The mean ROC area of unenhanced digital image was 0.9168. 3. The mean ROC area of enhanced digital image was 0.9339. 4. The diagnostic ability of three imaging methods was not significant difference(p>0.05). So, the digital images had similar diagnostic ability of artificial proximal caries to conventional radiographs. If properly enhanced digital image, it may be superior to conventional radiographs.

• 한국융합학회논문지
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• 제7권6호
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• pp.133-139
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• 2016

본 연구는 최근 새롭게 개발된 fTCP와 현재 치과임상에서 재광화 크림으로 널리 사용되고 있는 CPP-ACP의 재광화 효과를 비교하기 위하여 QLF-D를 이용하여 인공우식병소에서 fTCP와 CPP-ACP의 무기질소실 변화를 평가하고자 하였다. 실험에 사용된 우치시편은 탈회용액에 10일간 보관하여 인공우식병소를 형성하였고, 무작위로 두 군으로 분류하였다. 1군은 10% CPP-ACP가 포함된 Tooth Mousse 군이고, 2군은 fTCP가 포함된 Clinpro Tooth Creme군이다. 두 종류의 치아크림을 각각 탈회병소에 바르고 1주일간 인공타액에 침전 후 QLF-D를 이용하여 병소의 형광소실량(${\Delta}F$)을 평가하였다. QLF-D 분석결과 Tooth Mousse군은 처치 후에 ${\Delta}F$값과 ${\Delta}Fmax$값이 각각2.65, 6.63 증가하여 무기질 소실이 통계적으로 유의하게 감소(p<0.05)한 반면, Clinpro Tooth Creme군은 통계적으로 유의한 차이가 없었다. 또한 ${\Delta}Fmax$값에서는 처치 후 Tooth Mousse군이 Clinpro Tooth Creme군에 비해 통계적으로 유의하게 감소하였다(p<0.05). 그러므로 10% CPP-ACP가 포함된 Tooth Mousse는 fTCP가 포함된 Clinpro Tooth Creme보다 초기우식병소의 재광화 치료에 더욱 효과적이다.

• Restorative Dentistry and Endodontics
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• 제24권3호
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• pp.495-502
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• 1999

Recently root caries is reported as an increasing oral disease Many researchers studied in vivo and in vitro enamel lesions but due to its peculiar structure and different chemical composition compared to the enamel, little effort has been made to root caries study. The purpose of this study is to compare and to evaluate the effect of pH on the progression of artificial root caries lesion. Under the constant degree of saturation, the specimens were divided into 4 groups(pH 4.3, 5.0, 5.5, 6.0). Each group was immersed in acid buffer solution for 1, 3, 5, 7 days and examined using the polarizing microscope. The results were as follows: 1. The body of the lesion in the dentin showed higher degree of positive birefringence compared to sound dentin. 2. The rate of progression of the lesion slowed as the pH increased. 3. In all groups, the lesion progressed rapidly at the initiation or the experiment but increased gradually as time elapsed. In conclusion, the study shows that the pH in the acid buffer solution influenced the rate of progression of the lesion in artificial root caries. Compared to the previous enamel study, the initial pattern of the lesion progressed rapidly and as time elapsed increased gradually.

• 대한치과교정학회지
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• 제49권4호
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• pp.246-253
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• 2019

Objective: To evaluate the effectiveness of three different caries-preventing agents on artificial caries in a Streptococcus mutans-based caries model. Methods: Sixty-five caries-free human molar enamel blocks were treated with a demineralization solution and a remineralization solution. The specimens were assigned to the following groups according to the caries-protective product applied: group A, chlorhexidine varnish; group B, fluoride-releasing chemically cured sealant; group C, fluoride-releasing lightcured sealant; group D, positive control (specimens that were subjected to de- and remineralization cycles without treatment with any caries-protective agents); and group E, negative control (specimens that were not subjected to de- and remineralization cycles). Samples in groups A-D were stored in demineralization solution with S. mutans and thereafter in artificial saliva. This procedure was performed for 30 days. Average fluorescence loss (${\Delta}F$) and surface size of the lesions were measured using quantitative light-induced fluorescence at baseline and on the 7th, 14th, and 30th days. Results: After 30 days, group A demonstrated a significant increase in ΔF and the surface size of the lesions, no significant difference in comparison with the positive control group, and a significant difference in comparison with the negative control group. Group B showed no significant changes in both parameters at any of the measurement points. While group C showed increased ${\Delta}F$ after 14 days, no significant fluorescence change was observed after 30 days. Conclusions: Both fluoride-releasing sealants (chemically or light-cured) show anti-cariogenic effects, but the use of chlorhexidine varnish for the purpose of caries protection needs to be reconsidered.

• Restorative Dentistry and Endodontics
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• 제22권2호
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• pp.637-647
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• 1997

The purpose of this study was to evaluate the effect of concentration and pH of lactic acid on the formation of artificial root caries lesions formation in bovine teeth. The characterictics of artificially produced early root lesions were observed with polarized light microscope and the depth of lesions were mearsured with measuring microscope The results were as follows: 1. In the group of low pH and high concentration of lactic acid, the progress of lesion formation was faster than that of high pH and low concentration lactic acid group. 2. In the same group, initial lesion progress faster, but progression rate was reduced as time goes by. 3. In the development of initial root caries, cementum was act as a barrier to protect dentin from lesion progression.