Quantitative Light-induced Fluorescence-digital Research Articles

Development of a novel in vitro model for non-cavitated carious lesion formation reflecting carious lesion activity

BackgroundOral biofilms are a critical component in dental caries formation. However, current remineralization studies often overlook the impact of microbial factors. Therefore, a comprehensive clinically relevant assessment of caries is needed. This study aimed to develop a novel in vitro model capable of generating non-cavitated carious lesions that incorporates both mineral loss and microbial activity using quantitative light-induced fluorescence-digital (QLF-D) technology. MethodsA total of 44 artificial early carious lesions were formed using bovine incisors. The extent of fluorescence loss (ΔF) was analyzed using a QLF-D camera. Oral microcosm biofilms were then employed to construct 22 active and 22 inactive carious lesions. The red fluorescence emission rate (ΔR) and bacterial viability (RatioG/G+R) was measured using QLF-D camera and a live-dead bacterial assay, respectively. Independent t-tests were performed to compare ΔF, ΔR, and bacterial viability of artificial carious lesions according to their activity status. ResultsNo significant difference in ΔF between the lesions was found based on activity status (p = 0.361). However, the ΔR of active lesions was 1.82 times higher than that of inactive lesions, and the RatioG/G+R was 1.49 times higher in active lesions than in inactive lesions (both p < 0.001). ConclusionsThe significant differences observed in ΔR and RatioG/G+R between active and inactive lesions emphasize the importance of considering lesion activity status when evaluating the potential efficacy of remineralization agents. This study presents a novel in vitro remineralization assessment model that reflects carious lesion activity while controlling baseline mineral distributions of lesions.

Efficacy of Cold Atmospheric Plasma on Pathogenicity of Oral Microcosm Biofilms

This study aimed to compare the longitudinal efficacy between chlorhexidine gluconate (CHX; 0.12%) and cold atmospheric plasma (CAP) in reducing oral biofilm pathogenicity, utilizing a quantitative light-induced fluorescence-digital (QLF-D) camera. Oral microcosm biofilms were developed for 2 days on 57 hydroxyapatite disks. These biofilms were treated with distilled water for 1 min, CHX for 1 min, and CAP for 2 min over the course of 6 days. The red fluorescence intensities of the biofilms were measured using a QLF-D and expressed as pre- and post-treatment red/green ratios (RatioR/G). The bacterial viability (ratio of the green-stained area to the total stained area, RatioG/G+R) was calculated using live/dead bacterial staining; the total and aciduric bacterial counts were determined. A significant intergroup difference was found between RatioR/G changes according to the treatment period (p &lt; 0.001). The RatioR/G observed within the CAP-treated group was significantly lower compared with the CHX-treated group at every interval of measurement (p &lt; 0.001). The CAP-treated group also exhibited a lower RatioG/G+R and more weakened bacterial aggregation compared with the CHX-treated group (p &lt; 0.05). In the group treated with CAP, the counts of both total and aciduric bacteria were substantially reduced compared with the DW group, with a statistically significant reduction (p &lt; 0.001). Therefore, CAP may be more effective in minimizing oral microcosm biofilm pathogenicity than 0.12% CHX.

Red fluorescence intensity as a criterion for assessing remineralization efficacy in early carious lesions

ObjectivesEvaluating early carious lesion activity with an objective and clinically valid approach is crucial for developing effective treatment plans. Therefore, we here assessed the activity of non-cavitated carious lesions using a quantitative light-induced fluorescence-digital (QLF-D) camera and compared the remineralization efficiency after fluoride treatment according to the lesion's activity level. MethodsRed fluorescence emission rate (ΔR) and fluorescence loss (ΔF) were evaluated in 44 non-cavitated carious lesions by using a QLF-D camera. Based on the ΔR level, the lesions were classified into 22 active (ΔR ≥37.55) and 22 inactive carious lesions (ΔR <37.55). Each lesion was treated with 1.23 % fluoride gel for 60 s and then immersed into artificial saliva for 7 days. Subsequently, ΔR and ΔF changes in the lesions were measured. ResultsSignificant interactions between lesion activity and time were found for both ΔR and ΔF (p < 0.001). ΔR of active lesions declined faster and ΔF increased more steeply than did inactive lesions. Specifically, on day 7 post-fluoride treatment, the ΔR reduction rate was 1.40-times higher in active lesions, and the ΔF recovery rate was 2.50-times higher, indicating that active lesions respond more markedly to fluoride application. ConclusionsThis study highlighted the significance of ΔR in predicting remineralization efficiency in non-cavitated carious lesions after fluoride application. It underscored the importance of accurately assessing caries activity when formulating effective treatment plans. Lesion activity, as determined by ΔR, not only influences the outcome of remineralization treatments but also provides a more objective measure for tailoring caries management strategies.

Comparative Study on the Evaluation of Dental Bacterial Film Index Using Plaque Disclosing Agent and Quantitative Light Induced Fluorescence-Digital (QLF-D)

Comparative Study on the Evaluation of Dental Bacterial Film Index Using Plaque Disclosing Agent and Quantitative Light Induced Fluorescence-Digital (QLF-D)

QLF-D: A Contemporary Plaque Control Tool in Children.

Background and objectivesThe main causative factors for maximum periodontal diseases are dental plaque and oral biofilms. This study was done to check the impact of quantitative light-induced fluorescence-digital (QLF-D) as a motivational tool for plaque control among children from various schools situated in Dehradun district along with education using audiovisual aids.Materials and methodsA total sample of 800 school-going children including both males and females aged 6 to 12 years from various schools situated in Dehradun district of Uttarakhand were surveyed. A pro forma was prepared and the demographics of the students were noted. All the students were first examined for the Oral Hygiene Index-Simplified (OHI-S) and then the random division was done into two groups, group A (Q-scan) and group B (basic diagnostic aids) for examination of plaque index.ResultsThe results of the study revealed that good OHI-S scores increased significantly from 1st visit to 3rd visit. The plaque scores for the control group, when examined with basic diagnostic aids of all three visits, were significantly good which increased subsequently from 1st visit to 3rd visit. Good plaque index score increased significantly for the test group from 1st to 3rd visit when examined with QLF-D.ConclusionWe found in our study that QLF technology is of paramount importance in epidemiological surveys and plays a pivotal role in evaluating masses in maintaining oral health care.How to cite this articleSolanki R, Tuli A, Dhawan P, et al. QLF-D: A Contemporary Plaque Control Tool in Children. Int J Clin Pediatr Dent 2021;14(4):502–505.

Red fluorescence of plaque in the dentition-a comparison of Quantitative Light-induced Fluorescence-Digital (QLF-D) images and conventional images of disclosed plaque.

Quantitative Light-induced Fluorescence-Digital (QLF-D) detects red fluorescence of plaque, but is almost solely used on labial anterior tooth surfaces. As distribution and formation of plaque varies distinctly within the dentition, our aim was to investigate, how red fluorescing plaque is related to disclosed plaque depending on tooth type and surface. This was done with habitual plaque and after de-novo plaque formation. Thirty subjects were enrolled. QLF-Dimages of undisclosed plaque and conventional images of disclosed plaque were planimetrically analysed. Values were expressed as percentage of red fluorescing plaque (P%QLF-D) and of disclosed plaque (P%D) of the total tooth surface. Images were taken at baseline, after de-novo plaque formation (48 (T2) and 72 (T3) h without oral hygiene after professional tooth cleaning), and after 4-6 weeks of habitual oral hygiene (T4). At the tooth level, P%QLF-D was significantly lower than P%D on vestibular surfaces but reached similar levels on oral surfaces. De-novo plaque formation caused a significant increase in P%D on vestibular surfaces; this was not reflected by QLF-D. At the subject level, on vestibular surfaces and at baseline, some subjects exhibited minor but others gross differences between P%QLF-D and P%D. This was not the case at T3, but the same pattern appeared again at T4. On oral surfaces, the order of differences was more evenly scattered with no clear impact of the observation time point. Red fluorescence of dental plaque relates very differently to disclosed plaque depending on sites and maturation stages and has a significant inter-individual component.

Comparison of Quantitative light-induced fluorescence-digital (QLF-D) images and images of disclosed plaque for planimetric quantification of dental plaque in multibracket appliance patients

The purpose of the present cross-sectional clinical study was to check the ability of plaque detection and quantification by QLF-D against conventional digital photographs of disclosed plaque in multibracket appliance (MB) patients. 20 patients were included according to the following criteria: (1) upper and lower jaw treated by MB appliance, (2) patients being 16 years of age or older, (3) all central and lateral incisors as well as canines in situ, (4) absence of developmental defects, carious lesions, surface fillings, prosthetic restorations or recessions greater than 1/3 of root length in central/lateral incisors and canines as well as (5) declaration of consent. QLF-D and conventional photographs were analyzed planimetrically regarding plaque coverage on buccal and oral surfaces of central/lateral incisors and canines. The conventional photographs of stained plaque served as gold standard. On average, in QLF-D pictures 20.7% ± 17.4 of the tooth surfaces were covered with plaque, while the conventional photographs of disclosed plaque presented a mean plaque-covered area of 36.2% ± 23.5. The Bland-Altman plot for both imaging modalities showed a very large inconsistent scattering with both negative and positive deviations. The method discrepancy increased with increasing plaque coverage, thus indicating a systematic method error. On average, the deviation of the methods from the optimal line of accordance was −15.5%. In patients wearing MB appliances, there was no clinical significant agreement regarding the plaque-covered tooth surface depicted by QLF-D respectively conventional images of disclosed plaque. Due to the large method discrepancy, QLF-D is currently not reliable for precise plaque quantification in MB patients.

Comparison of dental plaque reduction after use of electric toothbrushes with and without QLF-D-applied plaque visualization: a 1-week randomized controlled trial

BackgroundTo evaluate the efficacy of a newly developed electric toothbrush in reducing dental plaque via a quantitative light-induced fluorescence-digital (QLF-D)-applied visualisation system in the brush head.MethodsParticipants included 20 adults aged 19 to 28 years. Participants were randomly assigned either (i) an electric toothbrush with a monitor to visualise red-fluorescent dental plaque via a camera built into the brush head (monitor usage group, n = 10) or (ii) an electric toothbrush without a monitor (monitor-non-use group, n = 10). The amount of dental plaque was assessed by personal hygiene performance (PHP) at baseline and 1 week later.ResultsIn the monitor-usage group, PHP score was significantly lower at the 1-week follow-up than at baseline (6 vs 16; range, 0–12 vs 13–21; P = 0.029). This change was not observed in the monitor-non-use group (14 vs 13; range, 6–21 vs 2–26; P = 0.778). After 1 week, the change in PHP scores in the monitor usage group was significantly greater than that in the monitor non-use group (− 10 vs 0; range, − 21 to 9 vs − 8 to 16; P = 0.021).ConclusionsOur results clearly demonstrate that brushing teeth while looking at a monitor that depicts red-autofluorescent dental plaque via application of QLF-D improved the efficacy of dental-plaque removal relative to brushing teeth without a monitor.Trial registrationTrial registration number: UMIN000033699.Name of registry: Study on effect of new devise for oral care on dental plaque clearance.Date of registration: 8th September 2018.Status of registration: Completed.

Hand motor functions on the presence of red fluorescent dental biofilm in older community-dwelling Koreans.

The Quantitative Light-induced Fluorescence-Digital (QLF-D) system visualizes old and mature dental biofilm as red fluorescence. Risk factors for poor oral hygiene have been identified, however, few studies have evaluated the relationship between mature dental biofilm and hand motor functions. This study aimed to investigate the effects of two important manual motor functions for object manipulation -handgrip strength and manual dexterity- on the presence of red fluorescent dental biofilm in older community-dwelling Koreans using QLF-D, an optical device that reveals dental biofilm. This cross-sectional study included 70 Korean participants aged ≥65 years, all of whom completed questionnaires and were tested for handgrip strength and manual dexterity. In total, 840 dental surfaces were photographed using QLF-D, and ΔR20 values, which reflect mature dental biofilm accumulation, were calculated. The t-test was performed to analyze the differences in the ∆R20 values according to sociodemographic characteristics, health-related characteristics and hand motor functions, while multiple linear regression analysis was used to investigate the effects of hand motor functions on the ∆R20 values. Multivariate regression analysis revealed that handgrip strength (β = -0.294) was the factor most strongly affecting mature dental biofilm accumulation (ΔR20), followed by tooth-brushing time (β = -0.262) and manual dexterity (β = -0.241). Reductions in handgrip strength and manual dexterity were independent risk factors for pathogenic dental biofilm accumulation. The results of this investigation suggest that programs designed to prevent the decline, as well as improve, handgrip strength and manual dexterity might improve the oral hygiene of older adults.

Quantitative light-induced fluorescence assessment of white spots following semi-rapid maxillary expansion.

This study aimed to investigate if the semi-rapid maxillary expansion (SRME) can cause white spot lesion (WSL) formation using quantitative light-induced fluorescence digital (QLF-D). The SRME group comprised 15 patients (9 girls, 6 boys; 13.5 ± 1 years) who had transverse maxillary deficiency and underwent expansion with full-coverage expanders. The screw of the expanders in the SRME group was activated twice a day for the first week. After decementation at the end of the first week, the screw activation protocol was changed to 3 turns/ week. In the SRME group, the QLF-D images were captured before starting treatment and 3.18 ± 0.32 months later when the expansion treatment was completed. The control group consisted of 15 subjects (8 girls, 7 boys; mean age 14.2 ± 1.9 years) who never had orthodontic treatment. The images of the control group were obtained with 3 months interval. The images were analyzed in terms of demineralization using analysis software. The left central incisor was the only tooth that was affected by WSL formation in the SRME group after expansion. The left central incisor tooth's fluorescence levels were decreased and the lesion area increased significantly (p < 0.05). No significant mineralization changes occurred in the control group (p > 0.05). SRME resulted in WSL formation in the left central incisor, while other teeth were not affected by demineralization. Although providing adequate oral hygiene is easier during SRME due to the removable appliance, the orthodontist should still be aware that it may cause demineralization.

The effects of 8DSS peptide on remineralization in a rat model of enamel caries evaluated by two nondestructive techniques.

Nowadays, dental caries is one of the most common oral health problems, affecting most individuals. It has been found that, by remineralizing enamel at an early stage in the formation of enamel caries, teeth can be effectively protected from dental caries. In this work, a peptide with eight repetitive sequences of aspartate-serine-serine (8DSS) is applied as the bio-mineralizer in an in-vivo rat enamel caries model. Nondestructive quantitative light-induced fluorescence-digital (QLF-D) imaging and micro-computed tomography (micro-CT) are used to evaluate the remineralization of enamel carious lesions by measuring the total fluorescence radiance loss of the molar area (Δ QTotal), acquired using QLF-D imaging, and the mineral density and residual molar enamel volume, acquired using micro-CT. Correlations are explored between Δ QTotal and mineral density (strong correlation, r = 0.8000, p < 0.001) and Δ QTotal and residual molar enamel volume (moderate correlation, r = 0.6375, p < 0.001). Our results demonstrate that 8DSS is a promising in-vivo remineralization agent that exhibits comparable effects to NaF ( p < 0.05), which has been verified using the classical Keyes method. Moreover, the nondestructive QLF-D and micro-CT methods can be combined to quantify the remineralization of enamel carious lesions three-dimensionally in vivo, making them broadly applicable in quantifying hard tissues.

The reproducibility of assessment of white spot lesions adjacent to orthodontic brackets, with a quantitative light induced fluorescence digital camera at different rotations of teeth \u2013 an in vitro study

BackgroundA quantitative light-induced fluorescence digital (QLF-D) camera is able to assess demineralizations adjacent to orthodontic brackets. Rotations of teeth during and the presence of the orthodontic appliances may influence the longitudinal follow-up of such lesions over time.MethodsBrackets were bonded on extracted teeth: 54 incisors and 31 canines. Demineralizations were formed in vitro directly cervical of the bracket. Images were captured using a QLF-D camera mounted on an optical bench, equipped with a goniometer on a turntable. The teeth were placed in the goniometer simulating buccolingual rotation (0°, 10°, 20°), the turn-table was used for mesiodistal rotations (0°, 10°, 20°). Standardized QLF-D images were made before (with and without a wire) and after debonding at combinations of aforementioned angles of rotation. The image after debonding at 0° buccolingual and 0° mesiodistal rotation served as a control.ResultsThe presence of a bracket resulted in a significantly higher fluorescence loss, yet a smaller lesion area (p < 0.05) in comparison to the control. A significant higher fluorescence loss was seen for rotations towards lingual relative to the 0° buccolingual and 0° mesiodistal rotation, while the effect was less explicit towards buccal.ConclusionsFluorescence loss and lesion size are influenced by the angle of rotation under which the demineralization is photographed. The full extent of demineralizations is only apparent after debonding when photographed at rotations of 0° mesiodistal and up to 20° buccal. Precaution must be taken into account assessing demineralizations of patients undergoing treatment with fixed appliances when using a QLF-D camera.

Validity assessment of quantitative light-induced fluorescence-digital (QLF-D) for the dental plaque scoring system: a cross-sectional study

BackgroundThe aim of this study was to analyze the correlation between the dental plaque indices measured using quantitative light-induced fluorescence-digital (QLF-D) and conventional clinical indices that assess gingival status.MethodsFrom among the patients who visited Ewha Womans University Mokdong Hospital, 33 adults in their 20s who had relatively even teeth were selected for full-mouth QLF-D imaging. The images were used to analyze the QLF-D score and the QLF-D ΔR score. As clinical indices, the gingival index (GI), bleeding on probing (BOP), probing pocket depth (PPD), and patient hygiene performance (PHP) index were measured. The correlations between the QLF-D score and QLF-D ΔR score and each clinical index were analyzed. Analyses were performed comparing the indices of maxillary and mandibular teeth, the teeth on right and left sides of the mouth, anterior and posterior teeth, and buccal and lingual surfaces of each tooth. Pearson’s correlation analysis was conducted (p < 0.05).ResultsThe mean full-mouth QLF-D score was highly correlated with the GI, BOP, PPD, PHP index (p < 0.01). The mean full-mouth QLF-D score showed the highest correlation with GI (r = 0.749) and the lowest correlation with PPD (r = 0.683). The correlations between the QLF-D score were higher in the mandible than in the maxilla and in the anterior teeth than in the posterior teeth, while no significant differences were seen between the buccal and lingual surfaces of tooth.ConclusionsThis study concluded that the correlations between the plaque indices measured for each tooth surface area using QLF-D and the clinical indices assessed were significantly high, and it allowed objective determination of the gingival status. Therefore, the plaque index measured using QLF-D may be used as an alternative to supplement the shortcomings of conventional clinical indices for educating patients about plaque control and continued patient oral care.

Manual dexterity and dental biofilm accumulation in independent older adults without hand disabilities: A cross-sectional study.

This study investigated the relationship between manual dexterity and dental biofilm accumulation in independent older Koreans using Quantitative Light-Induced Fluorescence-Digital (QLF-D). This cross-sectional study included 44 participants recruited from senior welfare facilities in South Korea and aged ≥65 years. Participants were surveyed using face-to-face structured interviews; manual dexterity was assessed using the Box and Blocks Test. To evaluate dental biofilm accumulation, the 528 surfaces of six index teeth were imaged using QLF-D and then quantified into Simple Plaque Scores (SPS) and ΔR20 values. The t-test and one-way analysis of variance were used to analyze differences in SPS and ΔR20 according to general characteristics and manual dexterity. Those who brushed their teeth ≤2 times per day had higher SPS and ΔR20 values on the lingual surface of tooth #24 than those who brushed ≥3 times per day (p < 0.05). The low manual dexterity group had higher SPS on lingual surfaces of teeth #12, #24, and #32, as well as higher ΔR20 values on the lingual surfaces of teeth #12, #24, #32, and #44 (p < 0.05) than the normal group. The low manual dexterity group had more dental biofilm-particularly on the lingual surfaces of teeth-and more mature biofilm than the normal group. These findings indicate that reduced manual dexterity could be a predictor of poor oral hygiene in independent older adults without hand disabilities. Therefore, we suggest manual dexterity be assessed in advance of dental biofilm assessment and tooth brushing instruction.

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

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. 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. 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). Detecting and analyzing fluorescence signals can improve the ability to detect residual adhesive on a tooth and also provide thickness information.

Fluorescence change of Fusobacterium nucleatum due to Porphyromonas gingivalis.

The aim of this study was to measure changes in the fluorescence of Fusobacterium nucleatum interacting with Porphyromonas gingivalis for excitation with blue light at 405-nm. P. gingivalis was mono- and co-cultivated in close proximity with F. nucleatum. The fluorescence of the bacterial colonies was photographed using a QLF-D (Quantitative Light-induced Fluorescence-Digital) Biluminator camera system with a 405 nm light source and a specific filter. The red, green and blue intensities of fluorescence images were analyzed using the image analysis software. A fluorescence spectrometer was used to detect porphyrin synthesized by each bacterium. F. nucleatum, which emitted green fluorescence in single cultures, showed intense red fluorescence when it was grown in close proximity with P. gingivalis. F. nucleatum co-cultivated with P. gingivalis showed the same pattern of fluorescence peaks as for protoporphyrin IX in the red part of the spectrum. We conclude that the green fluorescence of F. nucleatum can change to red fluorescence in the presence of adjacent co-cultured with P. gingivalis, indicating that the fluorescence character of each bacterium might depend on the presence of other bacteria.

Advantage of Introducing Quantitative Light-Induced Fluorescence in School Dental Checkups

Background: Caries detection in school oral examinations insufficient accuracy. Objective: To evaluate advantages of introducing quantitative light-induced fluorescence-digital (QLF-D) in school oral examinations. Methods: Experiment No. 1. Early demineralized lesions in the upper and lower incisors and canines were visually inspected by three dentists and by QLF-D. The numbers of tooth planes with early demineralized lesions were compared between the methods. Experiment No. 2. Approximal demineralized lesions in molars were assessed by visual inspection, x-ray imaging, and QLF-D. The numbers of tooth planes with demineralized lesions were compared among the methods. Experiment No. 3. Plaque distribution was evaluated by QLF-D and a traditional staining method. The ratio of the diameter of plaque to tooth crown in the tooth axis direction in each method was calculated. The results were evaluated by Pearson’s correlation coefficient analysis and Bland-Altman plot. Results: Experiment No. 1. The three dentists found 0.67 tooth planes on average. QLF-D found 22 tooth planes with early demineralized lesions in the same samples. Experiment No. 2. Fourteen approximal tooth planes of molars were found to have demineralized lesions by x-ray imaging. QLF-D detected 71.4% of the tooth planes out of the 14, whereas visual inspection found 7.1%. Experiment No. 3. The Pearson’s correlation coefficient for the evaluations of plaque distribution between the QLF-D and traditional staining methods was 0.77 (P < 0.001). No statistically significant systematic error was found through the Bland-Altman Plot analysis. Conclusion: The results support introduction of QLF-D for use in school dental examinations.

Development of a fluorescence-image scoring system for assessing noncavitated occlusal 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.

Validation of quantitative light-induced fluorescence-digital in the quantification of demarcated hypomineralized lesions of enamel.

The aim of the present study was to determine the validity of quantitative light-induced fluorescence-digital (QLF-D) in regard to the detection and quantification of developmental demarcated hypomineralized lesions of enamel in vitro when compared to micro-computed tomography (CT) determination of lesion characteristics. A secondary aim was to develop a protocol for 3-D analysis using micro-CT. Twenty-four hypomineralized defects were classified as cream/white (CW), yellow/brown (YB), and post-eruptive breakdown. Teeth were scanned using micro-CT. Grayscale and chromatic vertical sections were constructed. Mineral density and porosity percentage were calculated. Fluorescence loss and red fluorescence were determined from images. Linear mixed models were computed. Mineral density and porosity mean values by lesion type were statistically different (P<.001). CW lesions had lower fluorescence loss than YB and broken lesions. Red fluorescence was emitted by the majority of the defects, and the means between lesion types were statistically different (P<.001). The mixed model indicated that mineral density was not correlated with fluorescence loss and lesion type. The present findings support QLF-D as a method to detect hypomineralized lesions of different clinical presentation, with red fluorescence putatively related to the severity of the defects. The micro-CT 3-D approach is a reliable method to analyze structural changes in hypomineralized enamel.

Photodiagnosis of White Spot Lesions after Orthodontic Treatment with a Quantitative Light-induced Fluorescence-Digital System: A Pilot Study.

To confirm that the quantitative light-induced fluorescence-digital (QLF-D) system is an adequate tool for monitoring changes in the mineral contents of white spot lesions. Twenty-three anterior teeth from five orthodontic patients were selected for the samples. Initial fluorescent images were taken with the QLF-D system immediately after removing the fixed orthodontic appliances, and the white spot lesions were visualised in the fluorescent images that were selected. Subsequently, a fluoride varnish containing 0.1% fluoride was applied to all white spot lesions, and the final QLF-D images were taken two weeks after fluoride treatment. Finally, the following four parameters were compared between the images taken at baseline and two weeks after the treatment with paired t-tests: the mean fluorescence loss (∆F), maximum fluorescence loss (∆Fmax), lesion area (area), and lesion volume (∆Q). All the parameters obtained by QLF-D after two weeks had improved significantly when compared with baseline (p < 0.01). The recovery rates of the ∆F, ∆Fmax, area, and ∆Q were 11.4%, 17.1%, -37.5%, and 42.1%, respectively. Shallow lesions (∆Fi ≥ -15%) were better remineralized than deep lesions (∆Fi < -15%). The ratios of the ∆F, ∆Fmax, area, and ∆Q parameters between the shallow and deep lesions were 2.86, 3.30, 2.20, and 1.88, respectively. The QLF-D system is a sensitive tool for the assessment of small levels of mineral changes in carious lesions after the removal of orthodontic appliances.