The quantification of fluorescence in dental plaque is currently being developed as a diagnostic tool to help inform and improve oral health. The oral anaerobe Prevotella intermedia exhibits red ...fluorescence due to the accumulation of porphyrins. pH affects the fluorescence of abiotic preparations of porphyrins caused by changes in speciation between monomers, higher aggregates and dimers, but this phenomenon has not been demonstrated in bacteria. Fluorescence spectra were obtained from suspensions of P. intermedia that were adjusted to pHs commensurate with the range found within dental plaque. Two fluorescent motifs were identified; 410 nm excitation / 634 nm emission (peak A) and 398 nm excitation / 622 nm emission (peak B). A transition in the fluorescence spectra was observed from peak A to peak B with increasing pH which was also evident as culture age increased from 24 hours to 96 hours. In addition to these 'blue-shifts', the intensity of peak A increased with pH whilst decreasing with culture age from 24 to 96 hours. A bacterium's relationship with the local physiochemical environment at the time of image capture may therefore affect the quantification of dental plaque fluorescence.
Quantitative light‐induced fluorescence (QLF) technology can detect some dental plaque as red fluorescence. This in vivo study aimed to identify the microbial characteristics of red fluorescent (RF) ...dental plaque using 16S rRNA gene sequencing and evaluate the correlations between RF plaque and the clinical symptoms of dental diseases. Paired supragingival plaque samples collected from each 10 subjects and consisted of RF and non‐RF dental plaques as observed by QLF technology using a 405 nm blue light source for excitation. The characteristics of the bacterial communities in the RF and non‐RF plaque samples were compared by sequencing analysis. An increase in microbial diversity was observed in RF plaque compared with the non‐RF plaque. There were significant differences in the community compositions between the 2 types of dental plaque. Periodontopathic bacteria were significantly more abundant in the RF plaque than non‐RF plaque. The fluorescence intensity of RF plaque was significantly related to the proportion of the periodontopathic bacterial community and the presence of gingival inflammation. In conclusion, the plaque red fluorescence is associated with changes in the microbial composition and enrichment of periodontopathic pathogens, which suggests that RF plaque detected by QLF technology could be used as a risk indicator for gingival inflammation.
Detection of pathogenic dental plaque is essential for the primary prevention of dental diseases. Quantitative light‐induced fluorescence (QLF) technology can visualize some dental plaque as red fluorescence. This study confirmed that the red fluorescent plaque was associated with enrichment of periodontopathic microbiota and clinical symptoms of gingival inflammation, which suggests that QLF technology could be a clinically significant method to detect high‐risk dental plaque potentially causing gingivitis.
Abstract
We aimed to determine whether dye-enhanced quantitative light-induced fluorescence (DEQLF), wherein porous structure of caries lesions is stained with a fluorescent dye, could quantitatively ...distinguish between active and inactive caries. A total of 126 bovine specimens were prepared to artificially simulate caries activity. Active caries were demineralized with 1% carbopol solution for 3 (A
3
), 5 (A
5
), and 10 days (A
10
). For inactive caries, half specimens in each group were remineralized with 2% NaF and reallocated into three groups (I
3
, I
5
, and I
10
, respectively). Wet specimens were dried with compressed air for 10 s and then dyed with 100-µM sodium fluorescein for 10 s. Fluorescence images of speicmens were captured with a QLF-digital 2 + Biluminator. Fluorescence intensity (ΔG) was measured in fluorescence images of dyed specimens. ΔG between active and inactive groups was compared using independent
t
-test, and ΔG among active groups (or inactive groups) were compared using ANOVA (α = 0.05). ΔG in the active groups was 33.7–59.0 higher than that in the inactive groups (
P
< 0.001). Except between I3 and I5, there was significant differences in ΔG according to the demineralization period (
P
< 0.001). DEQLF might be used to evaluate early caries activity, and longitudinally monitor changes in lesion activity.
Fluorescence fingerprints of oral bacteria Kang, Si‐Mook; Josselin de Jong, Elbert; Higham, Susan M. ...
Journal of biophotonics,
January 2020, 2020-Jan, 2020-01-00, 20200101, Letnik:
13, Številka:
1
Journal Article
Recenzirano
The rapid detection and identification of microorganisms is one of the most important factors in many cases of ill health. The purpose of this study was to determine the fluorescence characteristics ...of seven oral bacteria using emission spectra with the aim of distinguishing between the bacteria, and to compare fluorescence imaging methods for the direct assessment of oral bacteria. Fluorescence images of each bacterium were obtained under a 405‐nm light source using a two‐filter system. The emissions of all samples were measured with a fluorescence spectrometer. The complete fluorescence data set collected for each sample employed a three‐dimensional data cube. The differences in the autofluorescence characteristics of the seven oral bacteria were determined by principal components analysis (PCA). The fluorescence images of the oral bacteria varied with the genus and the filter system. The three‐dimensional excitation‐emission matrix fluorescence spectra exhibited distinctive fluorescence features associated with intracellular fluorophores. The seven bacteria could be clearly differentiated on the PCA score plot. The findings of this study indicate that oral bacteria can be identified based on their autofluorescence characteristics. Fluorescence spectroscopy coupled with PCA can be used to detect and classify oral bacteria.
We visualized seven oral bacteria based on their auto‐fluorescence and distinguished by combining excitation emission matrix fluorescence spectroscopy data and PCA analysis. It offers a fundamental proof of reasoning to develop the auto‐fluorescence imaging for rapidly detection and identifying of bacteria. These methods can be expanded and implemented in clinical applications.
For successful root canal treatment (RCT), it is essential to objectively assess the presence and activity of bacteria in the root canal system. However, current methods rely on subjective ...observations of root canal exudates. This study aimed to confirm whether real-time optical detection using bacterial autofluorescence can evaluate endodontic infection status by assessing the red fluorescence (RF) detected from root canal exudates.
During RCT, endodontic paper points were used to collect root canal exudates scored using conventional organoleptic tests to assess the severity of root canal infections. RF on the paper points was assessed using quantitative light-induced fluorescence (QLF) technology. RF intensity and area from the paper points were quantified, and their correlations with infection severity were assessed using their organoleptic scores. The oral microbiome composition of RF samples was compared with non-red fluorescent (non-RF) samples.
The RF detection rate was nil and >98% in the non-infectious and severe groups. The RF intensity and area significantly increased with infection severity (p<0.001) and showed strong correlations with organoleptic scores (r=0.72, 0.82, respectively). The diagnostic accuracy for detecting root canal infection using RF intensity was good to excellent (AUC = 0.81−0.95) and increased with infection severity. The microbial diversity of the RF samples was significantly lower than that of the non-RF samples. Gram-negative anaerobic bacteria such as Prevotella and Porphyromonas were more predominant in RF samples.
Optical detection using bacterial autofluorescence can objectively evaluate endodontic infection status in real-time by assessing the RF of endodontic root canal exudates.
This real-time optical technology can be utilised to detect endodontic bacterial infection without conventional incubation, allowing clinicians to determine the endpoint of chemomechanical debridement and increase the positive outcomes of RCTs.
The study aimed to determine whether the red fluorescence (RF) of a dental microcosm biofilm as measured with quantitative light-induced fluorescence (QLF) technology is useful for assessing the ...efficacy of antimicrobials. Dental microcosm biofilms were formed on bovine enamel discs and grown under 0.3% sucrose challenge and treated with chlorhexidine (CHX) solutions at different concentrations (0.05%, 0.1%, and 0.5%) plus a negative control sterile distilled water (DW) twice daily for 7 days. The biofilms were photographed using a QLF-digital system to evaluate the RF by calculating the red/green ratio, and pH values of the medium were measured daily. After 7 days, the bacterial viability of the biofilm was assessed by measuring the counts of viable total bacteria and aciduric bacteria, and the percentage surface microhardness changes (%SHC) was evaluated. The RF and cariogenic properties were compared for the different concentrations of CHX, and their correlations were examined. The RF and its increase rate were much lower for CHX-treated biofilms than for DW-treated biofilms. The RF after 7 days of maturation decreased significantly with increasing CHX concentrations (p<0.001) and was from 31% (for 0.05% CHX) to 46% (for 0.5% CHX) lower than that of the DW group. Strong correlations were reported between the RF of the 7-day-maturation biofilms and cariogenic properties, such as the number of total bacteria (r=0.93), number of aciduric bacteria (r=0.97), supernatant pH (r=0.43), and %SHC (r=0.98). In conclusion, the RF of dental biofilms as measured with QLF technology can be used to nondestructively assess and monitor the effect of antimicrobials against biofilm.
•All fluorescence parameter from three generations of QLF devices showed good to excellent validity in detecting enamel caries and in differentiating caries severity.•ΔF (which indicates the mineral ...contents) did not differ between the first-, second-, and third-generation QLF devices.•ΔR (indicating not only the microbial activity but also the mineral contents) had a higher validity for the third-generation device than for the first- and second-generation devices.
This study compared two fluorescence parameters (fluorescence loss ΔF and red fluorescence gain ΔR) among three generations of quantitative light-induced fluorescence (QLF) systems with the aim of determining the validities of these parameters in the three devices for differentiating the severity of enamel caries.
Forty-one extracted human premolars and molars with suspected enamel caries were selected. Fluorescence images of all teeth were obtained using first-, second-, and third-generation QLF systems (Inspektor Pro, QLF-D, and Qraycam, respectively). Fluorescence parameters were then calculated using proprietary software. All of the specimens were also categorized histologically using polarized-light microscopy (PLM) based on histological levels related to the lesion depth into sound enamel (S), caries limited to the outer half of the enamel (E1), and caries involving the inner half of the enamel (E2). The Mann-Whitney test with Bonferroni correction was used to compare fluorescence parameters among the three generations of systems. The sensitivity, specificity, and area under the receiver operating characteristics curve (AUC) at two thresholds (S/E1 for detecting enamel caries lesions and E1/E2 for differentiating the caries severity) were calculated for evaluating the validities of the fluorescence parameters obtained using all three generations of QLF devices.
ΔF did not differ significantly between the devices at any histological level. In addition, ΔF showed large AUCs at the thresholds of S/E1 and E1/E2 (0.97–0.98 and 0.89–0.90, respectively). On the other hand, ΔR was significantly higher for the third-generation device than for the first- and second-generation devices for E2 lesions (P < 0.001). At the S/E1 threshold, ΔR values of the first- and third-generation devices showed larger AUCs (0.96–0.97) compared with that of the second-generation device (0.91), whereas at the E1/E2 threshold the AUC was the largest for the third-generation device (0.87).
The ΔF fluorescence parameter did not differ between the three generations of QLF devices, and showed high validity values. In terms of ΔR, the devices of all generations also showed good diagnostic performance for quantifying and detecting enamel caries lesions, but the third-generation QLF system produced superior results.
Occlusal discoloration due to staining frequently occurs on the pits and fissures of teeth. Noncariogenic discoloration (non-CD) refers to the attachment of staining chromogens to sound surfaces, ...whereas cariogenic discoloration (CD) represents the discoloration of porous structures due to bacterial metabolites and mineral loss from the enamel surface. This study evaluated whether it is possible to distinguish between non-CD and CD on stained occlusal surfaces with fluorescence assessed by the quantitative light-induced fluorescence (QLF) technology. Sixty-two extracted human permanent teeth with suspected discolorations on the pit and fissure were examined. The maximum values of fluorescence loss (ΔFmax) and red fluorescence gain (ΔRmax) were calculated using QLF images. Using histology as the gold standard, it was found that 12 teeth were sound (non-CD), while 50 teeth had enamel and dentine caries (CD). The validity tests at the enamel histological caries level, ΔRmax (ρ = 0.80) were strongly correlated with the histology (P < 0.001). At the optimum threshold (105.0) of ΔRmax, it showed high levels of sensitivity and specificity (0.96 and 0.83, respectively). Therefore, QLF can be used to distinguish non-CD from CD on occlusal surfaces using red fluorescence values with high validity.
•QLF technology can be a useful screening tool for noncavitated occlusal lesion.•QLF score can be used to evaluate the severity and status of occlusal caries lesion nondestructively.•QLF score may be ...able to replace existing clincal examination in the future with excellent diagnostic ability for detecting noncavitated caries.
This study aimed (1) to develop a scoring system based on a quantitative light-induced fluorescence (QLF) score for the occlusal caries (QS-Occlusal) that standardizes the fluorescence properties of noncavitated lesions from QLF images, (2) to confirm the validity and reliability of QS-Occlusal, and (3) to determine whether it is possible to replace existing clinical examinations by image evaluations based on the developed QS-Occlusal for assessing occlusal caries lesions.
This clinical study investigated 791 teeth of 94 subjects. The teeth were assessed by visual and tactile examinations using ICDAS criteria and quantitative light-induced fluorescence-digital (QLF-D) image examinations. QS-Occlusal was divided into four stages (from 0 to 3) based on the progression level of the lesion and the fluorescence loss and red fluorescence on captured QLF-D images. Two trained examiners who were not involved in the visual examination evaluated occlusal fluorescence images using QS-Occlusal. The maximum loss of fluorescence (|ΔFmax|) and the maximum change in the ratio of red and green fluorescence (ΔRmax) were quantitatively analyzed by the QA2 software to detect differences between the QS-Occlusal groups. The modalities were compared in terms of sensitivity, specificity, and area under the receiver operating characteristics (AUROC) curve for three different thresholds of the ICDAS codes: 0 vs 1–4 (D1), 0–2 vs 3/4 (D2), and 0–3 vs 4 (D3).
|ΔFmax| increased significantly by about 4.7-fold (from 15.94 to 75.63) when QS-Occlusal increased from 0 to 3. ΔRmax was about 6.2-fold higher for QS-Occlusal=1 (49.74) than for QS-Occlusal=0 (8.04), and 21.6-fold higher for QS-Occlusal=3 (P<0.05). The new QS-Occlusal showed an excellent AUROC (ranging from 0.807 to 0.976) in detecting occlusal caries when optimum cutoff values were applied. The intra- and interexaminer agreements indicated excellent reliability, with ICC values of 0.94 and 0.86, respectively.
The QS-Occlusal proposed in this study can be used in the clinical detection of noncavitated lesions with an excellent diagnostic ability. This makes it possible to replace clinical examinations and intuitively evaluate the lesion severity and status relatively easily and objectively by applying this scoring system to fluorescence images.
Little is known about how the chemical composition of enamel affects the optical properties of teeth, but advances in technology allow this to be studied using white-light and fluorescent images. ...This study aimed to identify the variation in enamel chemical composition that may affect tooth optical properties, such as tooth color and autofluorescence.
Sixty-one specimens of extracted human molars were prepared. Raman spectrometry was used to assess chemical composition of enamel, and tooth color, and autofluorescence from enamel were evaluated by quantitative light-induced fluorescence (QLF) images. Pearson correlation and multiple linear regression analyses were used.
Enamel fluorescence was related to enamel composition rather than tooth color. The b* value from the fluorescence image had a moderate correlation with crystallinity (full-width at half-maximum: r = −0.433, p < 0.001) and laser-induced fluorescence intensity (r = 0.450, p < 0.001) from Raman spectroscopy. In multiple linear regression analysis, the chemical composition of the tooth had a significant effect on the b* value from the fluorescent image (R2 = 0.433, p < 0.001). In contrast, tooth color values (L*, a*, and b*) were not correlated with chemical composition.
The present study revealed that enamel autofluorescence in QLF was related to chemical composition of the enamel, particularly the inorganic‒organic interface. While enamel chemical composition can be detected only in a laboratory environment, enamel fluorescence by QLF may enable estimation in a dental clinic, which has implications for the field of tooth bleaching or esthetic restorative materials.
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