• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.3
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• pp.244-249
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• 2011

This in vitro study compared the remineralization of incipient interproximal caries in the presence of three glass ionomer cements(highly-filled glass ionomer cement, resin-modified glass ionomer cement, compomer) and a resin composite(control). Thirty-two extracted premolars were selected based upon the lack of any visible demineralization. The teeth were coated in a transparent acid resistant nail varnish leaving $3{\times}3$ mm square. The teeth were subjected to the demineralizing buffer for 3 days and quantitative light-induced fluorescence(QLF) images of the subjects were taken. Proximal restoration was simulated by placing tooth specimens and the various glass ionomer cements in closed containers with artificial saliva at $37^{\circ}C$ and pH 7.0 with constant circulation. Further QLF images were subsequently taken at 30, 60, and 90 days. The changes of mineral loss(${\Delta}Q$) were evaluated by QLF and the change of ${\Delta}Q$(${\Delta}{\Delta}Q$) were compared between groups in order to evaluate the effects of remineralization. All data were analyzed using ANOVA and the post-HOC Dunnett C multiple comparison test at p<0.05. While ${\Delta}Q$(changes of mineral loss) increased for all treatments, the increases for three glass ionomer groups were significantly higher than that for the resin group at first month period. As time went on, the amount of ${\Delta}{\Delta}Q$ decreased.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.3
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• pp.506-515
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• 2004

The objective of this study was to compare the rate of in vitro demineralization of bovine permanent (BP), human deciduous (HD) and human permanent (HP) enamel. Twenty aye flattened and polished enamel samples for each group (BP, HD, HP) were immersed in a demineralizing solution (0.1 mol/L lactic acid, 0.2% Carbopol 907, and 50% saturated hydroxyapatite) for 1, 2, 4 or 8 days. All 25 samples from each group were subjected to Quantitative light induced fluorescence analysis (QLF) and 5 samples from each group were randomly selected for Transverse Microradiography analysis (TMR). Integrated mineral loss (IML) and lesion depth (LD) were determined by TMR. The fluorescence radiance (FR) of sound enamel $(FR_S)$, demineralized enamel $(FR_D)$ were determined by QLF and FR ratio $(FR_D/FR_S)$ was calculated. Bovine enamel samples showed significant correlation between FR ratio and lesion depth(p<0.05) and deciduous enamel samples does not showed significant correlation between FR ratio and lesion depth(p>0.05). Permanent enamel samples showed significant correlation between FR ratio and lesion depth(p<0.05) The constant of demineralization time between FR ratio from regression analysis were as follows: bovine enamel was -4.643(p<0.05) deciduous enamel was -5.421(p<0.05) and permanent enamel was -4.435(p<0.05).

• Annual Conference on Human and Language Technology
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• 1996.10a
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• pp.189-195
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• 1996

본 논문에서는 자연어를 통한 웹 정보검색 모델을 제시하고, 이를 위한 한국어 처리 방법을 소개한다. 자연어 질의에 대해 범주 문법에 기반한 구문 중심의 의미 파싱을 통해 QLF(quasi logical form)을 생성하며, 의미의 선택 제약 방법을 통해 모호성을 제거한다. QLF의 담화 처리를 통해 session 기반의 웹 검색을 실현할 수 있는 방법을 제안한다.

• Transactions on Electrical and Electronic Materials
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• v.13 no.6
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• pp.310-316
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• 2012

A new method for early caries diagnosis was proposed and tested through a home-made optical examination system that used quantitative light fluorescence (QLF) and digital imaging fiber optic transillumination (FOTI) (DIFOTI), with light sources across a wide spectral range, from 350 nm to 1,000 nm. The front-illuminated infrared light scattering image (FIR) showed similar diagnostic abilities to that of DIFOTI. The FIR method was invented based on the observation that caries lesions lose the high transmittance and low scattering properties of benign enamel tissue. There are various methods for the early diagnosis of caries, such as visual examination, exploration, X-ray radiography, QLF, FOTI, and infrared fluorescence (diagnodent). Among them, methods based on optical properties are regarded as having the most potential. A comparative study was performed between the FOTI, QLF, diagnodent, optical coherence tomography, and FIR scattering image methods, using 20 extracted teeth samples with early caries. A scale of lesion measurement based on optical image contrast was proposed. The statistical analysis showed a significant correlation between the DIFOTI and FIR methods (r = 0.35, p < 0.05). However, the QLF and diagnodent methods showed little association with FIR images, as they have different detection principles as compared with FIR. Tomographic images obtained by OCT, using 1,330 nm super luminescent LED as a gold standard of tooth structure, verified that the FOTI and FIR results correctly represented the lack of homogeneity in dental tissue. The newly proposed FIR method attained similar diagnostic results to those of FOTI, but with an easier approach.

• Journal of dental hygiene science
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• v.21 no.4
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• pp.219-226
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• 2021

Background: Proper detection and management of dental plaque are essential for individual oral health. We aimed to evaluate the maturation level of dental plaque using a two-tone disclosing agent and to compare it with the fluorescence of dental plaque on the quantitative light-induced fluorescence (QLF) image to obtain primary data for the development of a new dental plaque scoring system. Methods: Twenty-eight subjects who consented to participate after understanding the purpose of the study were screened. The images of the anterior teeth were obtained using the QLF device. Subsequently, dental plaque was stained with a two-tone disclosing solution and a photograph was obtained with a digital single-lens reflex (DSLR) camera. The staining scores were assigned as follows: 0 for no staining, 1 for pink staining, and 2 for blue staining. The marked points on the DSLR images were selected for RGB color analysis. The relationship between dental plaque maturation and the red/green (R/G) ratio was evaluated using Spearman's rank correlation. Additionally, different red fluorescence values according to dental plaque accumulation were assessed using one-way analysis of variance followed by Scheffe's post-hoc test to identify statistically significant differences between the groups. Results: A comparison of the intensity of red fluorescence according to the maturation of the two-tone stained dental plaque confirmed that R/G ratio was higher in the QLF images with dental plaque maturation (p<0.001). Correlation analysis between the stained dental plaque and the red fluorescence intensity in the QLF image confirmed an excellent positive correlation (p<0.001). Conclusion: A new plaque scoring system can be developed based on the results of the present study. In addition, these study results may also help in dental plaque management in the clinical setting.

• Journal of Korean society of Dental Hygiene
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• v.16 no.4
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• pp.525-530
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• 2016

Objectives: The purpose of the study is to investigate remineralization effect according to application cycle of fluoride varnish in preschool children. Methods: The study subjects were fifty six children (92 teeth) having one or more early dental caries lesion. Fluoride varnish was applied to the primary area of maxillary and anterior mandibular teeth with the interval of one month, three months, and six months. Results: Dft index was 3.54 in male and 3.44 in female. The fluorescence loss(${\Delta}F$) value due to early caries lesions showed a significant difference in experiment groups I and II after the application of fluoride varnish, but there was no significant difference in experiment group III. After fluoride varnish application, there was a significant change in experimental group I and III. The maximum fluorescence loss(${\Delta}Fmax$) from early caries lesions showed a significant difference after application of the fluoride varnish in all three experiment groups of I, II, and III(p<0.001). Conclusions: Fluoride varnish should be recommended and applied to the children of high risk caries group in every three months.

• Clean Technology
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• v.14 no.3
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• pp.153-159
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• 2008

The solubility of triclosan, an anti-acne agent was measured in supercritical carbon dioxide ($scCO_2$) with a variable volume view cell at 313.15, 323.15, and 333.15 K and at pressures between 10 and 40 MPa. We successfully correlated triclosan solubility in $scCO_2$ using the quasi-chemical nonrandom lattice fluid (QLF) equation of state. Triclosan was micronized using the rapid expansion of supercritical solutions (RESS) process. The effects of temperature and pressure on particle size were investigated using phase behavior data and correlated results from the QLF model.

• Journal of dental hygiene science
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• v.17 no.2
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• pp.116-122
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• 2017

The purpose of this study was to evaluate the detection ability of secondary caries using qunatitative light-induce fluorescence-digital (QLF-D) device. Twenty bovine teeth with cavity on surface were demineralized during 21 days for secondary caries lesion of cavity wall. After 21 days, cavity was filled using composite resin and cut the specimen in half with disc. Fluorescence loss of lesion on surface by time flow, cross sectional lesion, and lesion of filled or unfilled surface were analyzed using analysis software. ${\Delta}F$ (value of fluorescence loss) of the lesion on surface assessed by the QLF-D increased significantly over time up to 21 days. And ${\Delta}F$ value of lesion of filled surface is significantly lower than that of unfilled surface (p<0.001). ${\Delta}F$ of filled surface is 1.31 times of cross section lesion. The correlation of between ${\Delta}F$ of filled surface lesion and ${\Delta}F$ of cross section lesion was showed low agreement (0.026) and correlation of between ${\Delta}F$ of unfilled surface lesion and ${\Delta}F$ of cross section lesion was showed high agreement (0.613). In conclusion, secondary caries can be detected on surface using QLF-D. However, interference of fluorescence of filling material is the points to be especially considered for exact analysis of secondary caries lesion.

• The Journal of the Korean dental association
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• v.57 no.4
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• pp.213-220
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• 2019

Purpose: The aim of this study was to evaluate the red fluorescence characteristics of bacterial dental deposits assessed by quantitative light-induced fluorescence (QLF) technology and confirm whether the red fluorescence can distinguish and evaluate quantitatively accumulation of bacterial dental deposits. Methods: This retrospective cross-sectional study used QLF images captured at a dental clinic from January to December 2016. In each QLF image, a skilled examiner selected one region where the presence of deposits was suspected. Then, the regions were classified into three groups of not detectable deposits(ND), half detectable deposits (HD), and full detectable deposits (FD) by two examiners according to classification criteria. Only those images where the regions of bacterial dental deposits were classified identically by all examiners were used for analysis. The mean red fluorescence intensity (RFI) was defined as the mean value of R/G for all pixels in the regions. The RFI was compared between groups using Welch's ANOVA test, and the Spearman correlation was calculated to assess the association between RFI and accumulation of deposits. Results: In this study, 351 images among the collected images of 605 subjects were finally selected. The mean age of subjects was about 44 years. The R/G values of the ND, HD and FD were 0.73, 1.26 and 1.83 respectively. There were significant differences between all groups (p<0.001), and strong positive correlation was identified between the R/G value and the accumulation of deposits (r = 0.90, p<0.001). Conclusion: The intensity of red fluorescence as observed in the QLF images correlated well with the accumulation maturation of the deposits, which indicates that the QLF technology can be used to evaluate the status of oral hygiene.

• Journal of dental hygiene science
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• v.22 no.4
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• pp.199-205
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• 2022

Background: The use of dental floss is associated with a reduction in dental caries and periodontal disease. According to personal preference, not only thread type but also C type and Y type floss are used. Although the effectiveness of dental floss for removing dental plaque has been proven, plaque removal effect of C type and Y type floss has not been well reported. In this study, the plaque removal effect of C type and Y type floss compared to thread type floss was experimentally verified. Methods: Thread type, C type and Y type floss were used to remove dental plaque. Ten people in each flossing group participated, and by applying dental floss to the 6 incisors of the maxilla and mandible, the degree of dental plaque was analyzed by QLF-D. To evaluate the removal degree of dental plaque before and after flossing, Simple Plaque Score (SPS), Area R30, Area R70, and Area R120 score were measured. Results: In the analysis using the Area R30 fluorescence score of the QLF-D system, the degree of plaque removal according to the application of dental floss was effective in all the thread type (p=0.018), C-type (p=0.012), and Y-type (p=0.012) floss groups compared to before the application of the floss. Among them, C type floss was more effective in removing plaque than thread type and Y type floss. However, the plaque removal effect between the three floss types was not significantly different in ∆SPS (p=0.674), ∆Area R30 (p=0.726), ∆Area R70 (p=0.504), and ∆Area R120 scores (p=0.423). Conclusion: Thread type, C type, and Y type floss were all effective in removing dental plaque, but there was no significant difference in dental plaque removal effect according to the type of floss.