Bo-Ra Kim

Effect of nano-carbonate apatite to prevent re-stain after dental bleaching in vitro.

OBJECTIVES This study examined the effect of nano-carbonate apatite (n-CAP) to prevent re-staining and the change of enamel surface after dental bleaching in vitro. METHODS Twenty-four bovine specimens were bleached for 2 weeks with 10% carbamide peroxide (CP). After bleaching, the specimens were divided into the following four groups: distilled and deionized water (DDW, negative control), 10% n-CAP, NaF (positive control) and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP, positive control). Each group was subjected to pH cycling for 7 days. The specimens were treated for 4 min 3 times per day and re-staining was induced naturally by artificial saliva in the remineralization process. After pH cycling, the changes in colour were evaluated with spectrophotometry and scanning electron microscopy (SEM). The difference in colour between before and after pH cycling was evaluated using an ANOVA and Tukey test. RESULTS After pH cycling, the colour difference of n-CAP group was significantly lower than that of the DDW and CPP-ACP groups (p<0.05). SEM showed that n-CAP particles were deposited regularly on the damaged surface compared to the other groups. CONCLUSION 10% n-CAP could significantly maintain the initial colour and protect the damaged enamel structure after bleaching.

Assessing the use of Quantitative Light-induced Fluorescence-Digital as a clinical plaque assessment

BACKGROUND The aims of this study were to compare the relationship between red fluorescent plaque (RF plaque) area by Quantitative Light-induced Fluorescence-Digital (QLF-D) and disclosed plaque area by two-tone disclosure, and to assess the bacterial composition of the RF plaque by real time-PCR. METHODS Fifty healthy subjects were included and 600 facial surfaces of their anterior teeth were examined. QLF-D was taken on two separate occasions (before and after disclosing), and the RF plaque area was calculated based on Plaque Percent Index (PPI). After disclosing, the stained plaque area was analyzed to investigate the relationship with the RF plaque area. The relationship was evaluated using Pearson correlation and paired t-test. Then, the RF and non-red fluorescent (non-RF) plaque samples were obtained from the same subject for real-time PCR test. Total 10 plaque samples were compared the ratio of the 6 of bacteria using Wilcoxon signed rank test. RESULTS Regarding the paired t-test, the blue-staining plaque area (9.3±9.2) showed significantly similarity with the RF plaque area (9.1±14.9, p=0.80) at ΔR20, however, the red-staining plaque area (31.6±20.9) presented difference from the RF plaque area (p<0.0001). In addition, bacterial composition of Prevotella intermedia and Streptococcus anginosus was associated with substantially more the RF plaque than the non-RF plaque (p<0.05). CONCLUSIONS The plaque assessment method using QLF-D has potential to detect mature plaque, and the plaque area was associated with the blue-staining area using two-tone disclosure.

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.

Differences in the intensity of light-induced fluorescence emitted by resin composites

BACKGROUND The aims of this study were to compare the intensities of fluorescence emitted by different resin composites as detected using quantitative light-induced fluorescence (QLF) technology, and to compare the fluorescence intensity contrast with the color contrast between a restored composite and the adjacent region of the tooth. METHODS Six brands of light-cured resin composites (shade A2) were investigated. The composites were used to prepare composite discs, and fill holes that had been prepared in extracted human teeth. White-light and fluorescence images of all specimens were obtained using a fluorescence camera based on QLF technology (QLF-D) and converted into 8-bit grayscale images. The fluorescence intensity of the discs as well as the fluorescence intensity contrast and the color contrast between the composite restoration and adjacent tooth region were calculated as grayscale levels. RESULTS The grayscale levels for the composite discs differed significantly with the brand (p<0.001): DenFil (10.84±0.35, mean±SD), Filtek Z350 (58.28±1.37), Premisa (156.94±1.58), Grandio (177.20±0.81), Charisma (207.05±0.77), and Gradia direct posterior (211.52±1.66). The difference in grayscale levels between a resin restoration and the adjacent tooth was significantly greater in fluorescence images for each brand than in white-light images, except for the Filtek Z350 (p<0.05). However, the Filtek Z350 restoration was distinguishable from the adjacent tooth in a fluorescence image. CONCLUSIONS The intensities of fluorescence detected from the resin composites varied. The differences between the composite and adjacent tooth were greater for the fluorescence intensity contrast than for the colors observed in the white-light images.

Ecological changes in oral microcosm biofilm during maturation.

Abstract. The aim of this study was to evaluate the ecological changes in the biofilm at different stages of maturation using 16S rDNA gene amplicon sequencing and to identify correlations between red/green (R/G) fluorescence ratio and ecological changes. An oral microcosm biofilm was initiated from the saliva of a single donor and grown anaerobically for up to 10 days in basal medium mucin. Quantitative light-induced fluorescence analysis was shown that the R/G ratio of the biofilm increased consistently, but the slope rapidly decreased after six days. The bacterial compositions of 10 species also consistently changed over time. However, there was no significant correlation between each bacteria and red fluorescence. The monitoring of the maturation process of oral microcosm biofilm over 10 days revealed that the R/G ratio and the bacterial composition within biofilm consistently changed. Therefore, the R/G fluorescence ratio of biofilm may be related with its ecological change rather than specific bacteria.

Cutoff fluorescence loss for the recovery of incipient carious lesions after fluoride application in primary teeth: A clinical study

PURPOSE Early detection and diagnosis of incipient caries are the keys to achieving a favorable prognosis. Monitoring of pathological changes based on clinical evidence leads to an accurate prognosis. Therefore, this clinical study investigated changes in minerals of incipient carious lesions using quantitative light-induced fluorescence-digital (QLF-D) after applying professional fluoride treatment to children, with improvement of the lesion severity assessed based on the fluorescence loss (ΔF) value obtained using QLF-D. METHODS This study examined 90 incipient enamel lesions on the primary teeth of 27 children aged between 4 and 10 years. QLF-D images were obtained before and after the application of 1.23% acidulated phosphate fluoride gel for 1 min, and the ΔF values at 0 and 4 weeks (ΔF(0) and ΔF(4), respectively) and the recovery rates (RΔF) of the lesions were evaluated. Receiver operating characteristic curve analysis was used to calculate the cutoff ΔF(0) value at which recovery of the lesion with fluoride treatment remained feasible. RESULTS AND CONCLUSION The recovery patterns of ΔF 4 weeks after fluoride application differed depending on the ΔF(0) values. The incipient lesions with ΔF(0) values of less than -13.00 recovered 4 weeks after fluoride application (P <  0.001) and had an average RΔF value of 19.27%. The results indicate that a ΔF(0) cutoff value can be determined for predicting the effects of remineralization after fluoride application and quantitative prognostic data can be provided to patients.

1053 TREATMENT WITH CLEVUDINE FOR 24 WEEKS RESULTS IN SUSTAINED ANTIVIRAL RESPONSE ASSOCIATED WITH CONTINUED HBsAg DECREASE 24 WEEKS POST-TREATMENT IN HBeAg-POSITIVE PATIENTS

viral replication, with mean maximum reductions in HCVRNA ranging from −0.97 to −2.13 (log10 IU/mL). In this study, the safety and efficacy of FBV in combination with pegylated interferon alfa-2a (pegIFN) and ribavirin (RBV) was evaluated. Methods: Eligible patients (treatment naive, HCV genotype 1) were randomized 1:1:1:1 to receive FBV (200, 300 or 500mg BID) or placebo in combination with pegIFN (180 ug/wk) and RBV (1000/1200mg/day) for 4 weeks. Patients are continuing on open label pegIFN/RBV for an additional 44 weeks. Results from the Week 4 analysis are described here. HCVRNA was measured using the Roche COBAS Taqman (LLD= 25 IU/mL). Results: A total of 35 patients were enrolled and 34 completed Week 4. The majority were Caucasian (69%), genotype 1a (80%) and male (51%). The most frequently reported AEs were headache, fatigue, insomnia and nausea. There were no trends towards increased frequency or severity of AEs with increasing dose of FBV. The incidence and severity of laboratory test abnormalities was similar across treatment groups. There was one treatment-related SAE (elevated creatinine) in the FBV 300mg group, which resolved following IV hydration. No other renal AEs were reported. The mean reduction (log10 IU/mL) in HCVRNA at Day 4 for placebo (n = 8), 200 (n = 10), 300 (n = 9) and 500 (n = 8) mg BID was −0.58, −2.29, −2.72 and −2.83, respectively, and −2.10, −4.46, −4.67 and −3.62 at Day 28. The percent of patients achieving RVR (undetectable HCVRNA by Week 4) for placebo, 200, 300 and 500mg BID was 0%, 60%, 75% and 63%, respectively. Of those patients treated with 200, 300 and 500mg BID who achieved a RVR, 33%, 33% and 80% achieved undetectable HCVRNA within two weeks of treatment, respectively. Conclusions: The addition of FBV to pegIFN/RBV was well tolerated and markedly increased the percentage of patients achieving RVR. Assessment of response to pegIFN/RBV therapy subsequent to Week 4 is ongoing.

Detection of residual resin-based orthodontic adhesive based on light-induced fluorescence

INTRODUCTION This study evaluated the fluorescence of orthodontic adhesives using quantitative light-induced fluorescence-digital (QLF-D) images, and compared differences in the color characteristics of the fluorescence between adhesive and the adjacent tooth with that under white-light illumination in specimens containing residual adhesive of various thicknesses. METHODS Disc-shaped adhesive samples and samples comprising adhesive attached to extracted human teeth were prepared using Transbond XT, Blugloo, and Enlight, and they were ground to thicknesses ranging from 800 to 20 μm. Fluorescence and white-light images of the two types of specimens were taken with a QLF-D system. The color parameters for the fluorescence from the discs and the color difference (ΔE) between residual adhesive and the adjacent tooth were quantified in images using the CIE L*a*b* system. RESULTS The fluorescence color values of the discs differed significantly among the three adhesive products (P <  0.05). The ΔE values in fluorescence (ΔEF) and white-light (ΔEW) images for all three adhesives were lower for thinner residual adhesive specimens. The thickness of the adhesive could be perceived over a range of 50-100 μm for fluorescence images and 400-800 μm for white-light images (ΔE > 3.3). ΔEF was significantly larger than ΔEW for all of the residual adhesives, Blugloo specimens thicker than 100 μm, and Transbond XT and Enlight specimens thicker than 50 μm (P <  0.05). CONCLUSIONS Detecting and analyzing fluorescence signals can improve the ability to detect residual adhesive on a tooth and also provide thickness information.