치약 내 불소의 생리적 가용능 평가

Objectives : The aims of this study were to determine the total fluoride concentration and bioavailable fluoride concentration in different toothpastes, based on a newly suggested method by the International Organization for Standardization (ISO), and to compare the measured concentrations with the concentrations written on the packaging. Methods : The concentrations of total fluoride (TF) and bioavailable fluoride (BF) were measured in six toothpastes. For the TF measurement, 1 g of each toothpaste was mixed with dipotassium hydrogen phosphate (K2HPO4), and hydrogen chloride (HCl) was placed. After 24 hours, the samples were centrifuged and total ionic strength adjustment buffer (TISAB) solution was added. For the BF measurement, the toothpaste was mixed with K2HPO4 for only 1 minute. The samples were centrifuged, and then HCl was placed and allowed to stand for 24 hours. The TISAB solution was added subsequently. The concentration of fluoride ions was measured using a fluoride ion-selective electrode and calculated against a standard curve. Results : The six toothpastes were composed of different fluoride compounds and abrasives. The measured TF concentration ranged from 624.99 ppm to 1,353.00 ppm, and the similarity to the declared fluoride concentration ranged from 53.48% to 93.31%. The measured BF concentration ranged from 587.61 ppm to 1,360.05 ppm, and the similarity to the expected fluoride concentration ranged from 41.97% to 93.80%. Two samples were clearly separated when the samples were centrifuged, whereas the remaining four samples had unclear supernatants. The clearly separated toothpastes (i.e., toothpastes 5 and 6) had BF concentrations that were similar to or lower than the declared fluoride concentrations and the measured TF concentrations. However, the unclearly separated toothpastes showed inconsistent relationships between the measured TF and BF concentrations. Conclusions : The measured TF and BF concentrations of the six toothpastes did not reach the expected fluoride concentration. This finding resulted from the different compositions and forms of the toothpastes. Therefore, the properties of toothpastes need to be considered when measuring their fluoride concentrations.ope

Validation of quantitative light-induced fluorescence-digital (QLF-D) for the detection of approximal caries in vitro

OBJECTIVES: Detection of approximal caries lesions can be difficult due to their anatomical position. This study aimed to assess the ability of the quantitative light-induced fluorescence-digital (QLF-D) in detecting approximal caries, and to compare the performance with those of the International Caries Detection and Assessment System II (ICDAS II) and digital radiography (DR). METHODS: Extracted permanent teeth (n=100) were selected and mounted in pairs. The simulation pairs were assessed by one calibrated dentist using each detection method. After all the examinations, the teeth (n=95) were sectioned and examined histologically as gold standard. The modalities were compared in terms of sensitivity, specificity, areas under receiver operating characteristic curves (AUROC) for enamel (D1) and dentine (D3) levels. The intra-examiner reliability was assessed for all modalities. RESULTS: At D1 threshold, the ICDAS II presented the highest sensitivity (0.80) while the DR showed the highest specificity (0.89); however, the methods with the greatest AUC values at D1 threshold were DR and QLF-D (0.80 and 0.80 respectively). At D3 threshold, the methods with the highest sensitivity were ICDAS II and QLF-D (0.64 and 0.64 respectively) while the method with the lowest sensitivity was DR (0.50). However, with regard to the AUC values at D3 threshold, the QLF-D presented the highest value (0.76). All modalities showed to have excellent intra-examiner reliability. CONCLUSIONS: The newly developed QLF-D was not only able to detect proximal caries, but also showed to have comparable performance to the visual inspection and radiography in detecting proximal caries.ope

Association between the cariogenicity of a dental microcosm biofilm and its red fluorescence detected by Quantitative Light-induced Fluorescence-Digital (QLF-D)

OBJECTIVE: This study evaluated whether Quantitative Light-induced Fluorescence-Digital (QLF-D) can detect the levels of cariogenicity of dental microcosm biofilms by assessing the red fluorescence intensity. METHODS: Dental microcosm biofilms were initiated from human saliva on bovine enamel discs. Biofilms with various levels of cariogenicity were then grown in artificial saliva supplemented with sucrose at different concentrations (0.05%, 0.1%, 0.2%, and 0.5%) in 24-well microplates. After 10 days, fluorescence images of the biofilms were captured by the QLF-D to analyse the red fluorescence intensity, which was quantified as the red/green ratio (R/G value). The supernatant pH was also measured, as well as the total and aciduric bacteria counts of the collected biofilms. Mineral loss in enamel was also evaluated by calculating the percentage of surface microhardness changes (%SHC). RESULTS: The R/G values of the biofilms differed significantly with the sucrose concentration (p<0.0001), increasing consistently as the sucrose concentration increased from 0.05% (=0.91) to 0.5% (=2.56). Strong correlation was identified between the R/G value and the number of aciduric bacteria (r=0.83, p<0.0001), supernatant pH (r=-0.95, p<0.0001), and %SHC (r=0.90, p<0.0001). CONCLUSIONS: The red fluorescence as observed by the QLF-D was correlated with the cariogenic properties of dental microcosm biofilms in vitro, which indicates that this device can be used to detect the levels of cariogenicity of a dental biofilm. CLINICAL SIGNIFICANCE: The QLF-D is able to assess the cariogenic levels of dental plaque based on the intensity of red fluorescence.ope

Validity and reliability of autofluorescence-based quantification method of dental plaque

BACKGROUND: The aim of this study was to evaluate validity and reliability of autofluorescence-based plaque quantification (APQ) method. METHODS: The facial surfaces of 600 sound anterior teeth of 50 subjects were examined. The subjects received dental plaque examination using Turesky modified Quigley Hein plaque index (QHI) and Silness & Löe plaque index (SLI). The autofluorescence images were taken before the plaque examination with Quantitative Light-induced Fluorescence-Digital, and plaque percent index (PPI) was calculated. Correlation between two existing plaque indices and the PPI of the APQ method was evaluated to find which level of plaque redness on tooth (ΔR) by the APQ method shows the highest correlation. The area under the ROC curve (AUC) analysis and intra- and inter-examiner reliability tests were performed. RESULTS: The PPIΔR20 of the APQ method showed a moderate correlation with two existing plaque indices (rho of QHI=0.48, SLI=0.51). This methodology fell in the fair category and it had an excellent reliability. The APQ method also showed possibility to detect heavy plaque with fair validity. CONCLUSIONS: The APQ method demonstrated excellent reliability, and fair validity, compared with 2 conventional indices. The plaque quantification described has the potential to be used in clinical evaluation of oral hygiene procedures.restrictio

Early diagenesis of organic matter in Masan Bay, Korea

한국해양연구