Quantitative Light-induced Fluorescence Images Research Articles

Caries lesions diagnosis with deep convolutional neural network in intraoral QLF images by handheld device

ObjectivesThis study investigated the effectiveness of a deep convolutional neural network (CNN) in diagnosing and staging caries lesions in quantitative light-induced fluorescence (QLF) images taken by a self-manufactured handheld device.MethodsA small toothbrush-like device consisting of a 400 nm UV light-emitting lamp with a 470 nm filter was manufactured for intraoral imaging. A total of 133 cases with 9,478 QLF images of teeth were included for caries lesion evaluation using a CNN model. The database was divided into development, validation, and testing cohorts at a 7:2:1 ratio. The accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and area under the receiver operating characteristic curve (AUC) were calculated for model performance.ResultsThe overall caries prevalence was 19.59%. The CNN model achieved an AUC of 0.88, an accuracy of 0.88, a specificity of 0.94, and a sensitivity of 0.64 in the validation cohort. They achieved an overall accuracy of 0.92, a sensitivity of 0.95 and a specificity of 0.55 in the testing cohort. The model can distinguish different stages of caries well, with the best performance in detecting deep caries followed by intermediate and superficial lesions.ConclusionsCaries lesions have typical characteristics in QLF images and can be detected by CNNs. A QLF-based device with CNNs can assist in caries screening in the clinic or at home.Trial registrationThe clinical trial was registered in the Chinese Clinical Trial Registry (No. ChiCTR2300073487, Date: 12/07/2023).

Evaluation of residual dentin thickness using quantitative light-induced fluorescence technology.

This study aimed to determine whether a correlation exists between residual dentin thickness and quantitative light-induced fluorescence (QLF) values and, if so, to analyze its tendencies. Forty extracted sound human molars were assigned to filled and unfilled groups. The teeth were submerged in a mold with clear acrylic resin. Red utility wax was inserted into the pulp chamber space in the filled group to simulate vital pulp. The specimen was sectioned longitudinally to observe the inside of the pulp space. The samples were cut horizontally from the highest point of the pulp space 2mm apart. QLF images were then taken of 2mm, 1mm, and 0.5mm samples using the QLF-D Biluminator™ 2 + system. Three operators independently evaluated the QLF images, and the statistical analysis was conducted using one-way analysis of variance, Pearson correlation coefficients, and intraclass correlation coefficients. In the filled group, the mean ΔF values for residual dentin thicknesses of 2mm, 1mm, and 0.5mm were - 3.22, - 7.84, and - 11.52, respectively. In the unfilled group, the mean ΔF values were 0, - 6.90, and - 10.14, respectively. A positive correlation was found between residual dentin thickness and ΔF values (P < 0.05). The intraclass correlation coefficients for observations made by the three operators for the filled and unfilled groups were 0.831 and 0.917, respectively (P < 0.05). In conclusion, residual dentin thickness and ΔF values were significantly correlated and had a highly positive correlation regardless of the QLF device operator.

Tooth caries classification with quantitative light-induced fluorescence (QLF) images using convolutional neural network for permanent teeth in vivo

BackgroundOwing to the remarkable advancements of artificial intelligence (AI) applications, AI-based detection of dental caries is continuously improving. We evaluated the efficacy of the detection of dental caries with quantitative light-induced fluorescence (QLF) images using a convolutional neural network (CNN) model.MethodsOverall, 2814 QLF intraoral images were obtained from 606 participants at a dental clinic using Qraypen C® (QC, AIOBIO, Seoul, Republic of Korea) from October 2020 to October 2022. These images included all the types of permanent teeth of which surfaces were smooth or occlusal. Dataset were randomly assigned to the training (56.0%), validation (14.0%), and test (30.0%) subsets of the dataset for caries classification. Moreover, masked images for teeth area were manually prepared to evaluate the segmentation efficacy. To compare diagnostic performance for caries classification according to the types of teeth, the dataset was further classified into the premolar (1,143 images) and molar (1,441 images) groups. As the CNN model, Xception was applied.ResultsUsing the original QLF images, the performance of the classification algorithm was relatively good showing 83.2% of accuracy, 85.6% of precision, and 86.9% of sensitivity. After applying the segmentation process for the tooth area, all the performance indics including 85.6% of accuracy, 88.9% of precision, and 86.9% of sensitivity were improved. However, the performance indices of each type of teeth (both premolar and molar) were similar to those for all teeth.ConclusionThe application of AI to QLF images for caries classification demonstrated a good performance regardless of teeth type among posterior teeth. Additionally, tooth area segmentation through background elimination from QLF images exhibited a better performance.

Contemporary Diagnostic Approach of Natal Teeth in Identical Twins Utilizing Advanced Imaging Techniques: QLF and CBCT Imaging

Eruption of teeth at birth or immediately after is a rare phenomenon. The presence of teeth at birth is called natal teeth. However, the etiology of natal teeth is not deterministic. The natal teeth can lead to various medical associated problems and is also associated with various folklores and misconceptions. The diagnosis of natal teeth with its medical management along with counseling of the parents and family members is very important. The present case report provides an insight to the management of natal teeth in identical twins with a brief review of literature. Quantitative light-induced fluorescence imaging and cone beam computed tomography analysis of the teeth have also been done and compared with that of the primary dentition indicating hypo-mineralized tooth structure with decrease in radiodensity of the natal teeth. The present paper is a value addition in alternative diagnostic methods as an adjunct in the diagnosis of natal teeth and differentiating between the natal teeth and primary teeth.

Quantitative light-induced fluorescence (QLF) for diagnosis of enamel condition during various dental procedures

Relevance. Quantitative light-induced fluorescence (QLF) is widely used to diagnose the enamel condition during various dental interventions and allows for quick, objective and noninvasive assessment of the patient's oral hygiene status and follow-up of enamel de- and remineralization level.Materials and methods. The QLF technique used by the study increases the visual contrast between sound and diseased oral tissues when various (organic) substances in the mouth absorb light of a certain wavelength (different colours) and then re-emit the absorbed energy at a different wavelength. Filtration of illuminating light gives a fluorescent image or a QLF image. In a clinical setting, we used a QLF equipment set, namely, the Q-ray clinical software; Qraycam pro camera for full-arch imaging; Qraypen C intraoral camera; Qscan plus.Results. QLF was an additional tool for a practising dentist or dental hygienist, which allowed for the detection of the pathological process at the earliest stage, assisting in the diagnosis of the dental enamel condition, the detection of plaque without disclosing agents and assessment of its exact amount, contributing to the identification of hidden foci of enamel demineralization and carious lesions, cracks, tartar and oral hygiene evaluation.The analyzed data show the very high efficiency of the performed therapy with the 'R.O.C.S. medical 0+' remineralizing gel. The objective QLF data fully confirm the external elimination of white spots, and their almost complete disappearance is noted.Conclusion. Quantitative light-induced fluorescence and its parameters are essential not only for understanding the effectiveness of the applied techniques for bleaching, microabrasion, remineralization and other manipulations but also for their safety for dental enamel.

Evaluation of the clinical efficacy of quantitative light-induced fluorescence technology in diagnosing cracked teeth.

This retrospective study evaluated the clinical efficacy of quantitative light-induced fluorescence (QLF) technology for crack detection and the diagnosis of cracked teeth and assessed the possibility of a quantitative evaluation of cracks using QLF technology. Patients who were clinically diagnosed with cracked teeth over a 1-year period were included. The QLF images of the corresponding symptomatic cracked teeth and asymptomatic contralateral teeth with crack lines were taken with Qraypen C (AIOBIO, Seoul, Korea). Fluorescence loss (ΔF), maximum fluorescence loss (ΔFmax), red fluorescence (ΔR), and maximum red fluorescence (ΔRmax) of the crack line were analyzed. The correlation between these parameters and sex, age, tooth position (1st premolar, 2nd premolar, 1st molar, 2nd molar), spontaneous pain (+/-), percussion test (+/-), cold test (++/+/-), and bite test (+/-) were statistically analyzed. A total of 66 patients were included. Twenty-four patients had asymptomatic contralateral teeth with apparent crack lines; thus, 90 teeth were analyzed. The crack lines in 84 teeth observed as red fluorescent lines on the QLF images showed ΔR values higher than the cut-off value set by the analysis program used. The patient's age and the ∣ΔF∣ and ΔR values were positively correlated. However, there was no statistically significant difference in the QLF parameters between the same patient's symptomatic tooth and the contralateral tooth. QLF technology is a useful assistive diagnostic device for diagnosing cracked teeth.

Analysis of Quantitative Light-Induced Fluorescence Images for the Assessment of Bacterial Activity and Distribution of Tongue Coating.

This study aimed to verify and to validate the correlation between, and validate the assessment of, bacterial activity and the distribution of tongue coating, by analyzing quantitative light-induced fluorescence (QLF) images for the diagnosis of oral malodor. Oral malodor was measured using the Twin Breasor II, and bacterial activity and the distribution of tongue coating were investigated using QLF images. Bacterial activity and the distribution of tongue coating were quantitatively analyzed by dividing the tongue into six areas using the TB01 1.05 software. ROC curves were generated using MedCalc® software to validate the diagnosis of oral malodor, the testing of bacterial activity, and the distribution of tongue coating. Bacterial activity and the distribution of tongue coating showed a very strong association with each other (r = 0.937, p < 0.01), and were significantly higher in the oral malodor group (p < 0.05). The distribution of tongue coating was highly correlated with H2S (r = 0.223, p < 0.01) but not associated with CH3SH. Sensitivity, specificity, and the area under the curve confirmed the high accuracy of this method in assessing bacterial activity and the distribution of tongue coating in the diagnosis of oral malodor. Since QLF images provide significant accuracy during quantitative analysis in the identification of bacterial activity and the distribution of tongue coating, systematic management of tongue coating and reduced oral malodor can be achieved by actively using QLF images and oral malodor measurement.

Quantification of tongue coating using quantitative light-induced fluorescence-digital image analysis and its correlation with visual evaluation.

The tongue coating is a grayish-white deposit that quickly reflects the state of health or disease of the human body. Quantitative light-induced fluorescence (QLF) is a novel digital imaging system that objectively quantifies tongue coating. The present study aims to evaluate the correlation between the visual assessment of tongue coating and tongue coating by analysis of QLF-digital (QLF-D) images. This was an in vivo explorative study. Fifty children aged 11-13 years with clinically visible tongue coating were selected for the study. Tongue coating was assessed clinically by the Tongue Coating Index (Shimizu et al., 2007) and digitally by QLF-D Biluminator™ 2, C3 software. Data obtained were subjected to statistical analysis using SPSS 23.0 software. Spearman's rho correlation test was done, and P < 0.05 was considered statistically significant. A statistically significant correlation was found between the visual assessment scoring and the QLF image analysis for the evaluation of tongue coating. The Digital QLF tongue imaging system was found to be reliable due to its correlation with the clinical score and objective nature.

Comparative evaluation of remineralizing effect of fluoride and nonfluoride agents on artificially induced caries using different advanced imaging techniques.

Aim:The aim of the study is to evaluate and compare the in-vitro remineralization efficacy of remineralizing agents, i.e., fluoride-free toothpaste, fluoride toothpaste, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), CPP-amorphous calcium fluoride phosphate (CPP ACFP), and silver diamine fluoride (SDF) paste on dentine over time.Methodology:Seventy-five extracted human permanent molars were selected. The buccal section of these samples was shaped into a slab. Artificial caries was induced by dipping the samples into the demineralizing solution (pH 4.5) for 21 days. They were then divided into five groups (n = 15). Each experimental group underwent one of the following treatments: Group 1 – Fluoride-free toothpaste (negative control), Group 2 – Fluoride toothpaste (positive control), Group 3 – CPP-ACP, Group 4 – CPP-Amorphous Calcium fluoride Phosphate and Group 5 – SDF. Postremineralizing treatment, Scanning electron microscope, Energy dispersive X-ray and Quantitative light induced fluorescence imaging were carried out to analyze the remineralizing efficacy. The data obtained was then subjected to statistical analysis using ANOVA and Paired t-tests.Results:It was seen that SDF showed highest remineralization efficacy followed by CPP-amorphous calcium fluoride phosphate, CPP-ACP, fluoride toothpaste and fluoride-free toothpaste. The difference in mean value among the groups was statistically significant (P < 0.001).Conclusion:SDF showed the highest remineralizing potential in scanning electron microscopy and energy dispersive X-ray, followed by CPP-ACFP, CPP-ACP, Fluoride toothpaste, and Fluoride-free toothpaste. Quantitative light fluorescence analysis showed more fluorescence changes in the CPP-ACFP followed by CPP-ACP, Fluoride toothpaste, and Fluoride-free toothpaste.

Comparison of Clinical Characteristics of Fluorescence in Quantitative Light-Induced Fluorescence Images according to the Maturation Level of Dental Plaque

Other SectionsAbstractIntroductionMaterials and MethodsResultsDiscussionConflict of InterestEthical ApprovalAuthor contributionsReference

Detecting of Proximal Caries in Primary Molars using Pen-type QLF Device

The purpose of this &lt;i&gt;in vivo&lt;/i&gt; study was to assess the clinical screening performance of a quantitative light-induced fluorescence (QLF) device in detecting proximal caries in primary molars. Fluorescence loss, red autofluorescence and a simplified QLF score for proximal caries (QS-proximal) were evaluated for their validity in detecting proximal caries in primary molars compared to bitewing radiography. Three hundred and forty-four primary molar surfaces were included in the study. Carious lesions were scored according to lesion severity assessed by visual-tactile and radiographic examinations. The QLF images were analyzed for two quantitative parameters, fluorescence loss and red autofluorescence, as well as for QS-proximal. For both quantitative parameters and QS-proximal, the sensitivity, specificity and area under receiver operating curve (AUROC) were calculated as a function of the radiographic scoring index at enamel and dentin caries levels. Both quantitative parameters showed fair AUROC values for detecting dentine level caries (△F = 0.794, △R = 0.750). QS-proximal showed higher AUROC values (0.757 - 0.769) than that of visual-tactile scores (0.653) in detecting dentine level caries. The QLF device showed fair screening performance in detecting proximal caries in primary molars compared to bitewing radiography.

A novel model to predict tooth bleaching efficacy using autofluorescence of the tooth

ObjectivesWe aimed to confirm whether autofluorescence emitted from teeth can predict tooth bleaching efficacy and establish a novel model combining natural color parameters and tooth autofluorescence data to improve the predictability of tooth bleaching. MethodsA total of 61 tooth specimens were prepared from extracted human molars/premolars and immersed in 35% hydrogen peroxide for 1 h for tooth bleaching. The changes in laser-induced fluorescence (∆LIF) were assessed using Raman spectrometry. Tooth color and autofluorescence data were obtained using quantitative light-induced fluorescence (QLF) technology. Pearson correlation analyses were used to confirm the relationship between ∆LIF and autofluorescence. Intraclass correlation coefficients (ICC) were calculated to compare the conventional and new prediction models. Decision tree analysis was performed to evaluate clinical applicability. ResultsThe yellowness-to-blueness value from fluorescence imaging showed a moderate correlation with ∆LIF (r= –0.409, p = 0.001). The degree of agreement between the actual efficacy and that predicted by our novel model was high (ICC=0.933, p = 0.002). Decision tree analysis suggested that tooth autofluorescence could be a key factor in prediction of tooth bleaching outcomes. ConclusionsOur findings showed that autofluorescence detected from QLF images may be used to predict tooth bleaching efficacy. Our proposed model appeared to improve the predictability of tooth bleaching.

Evaluation of Periodontal Risk Factors with Quantitative Light-Induced Fluorescence Based Fluorescent Plaque Index, in Comparison to Radiographic and Oral Health Habit Scoring: A Retrospective Case Study.

The aim of this study was to evaluate periodontal risk factors with oral health habits and fluorescent plaque index (FPI) using quantitative light-induced fluorescence (QLF) images, and to evaluate their effect on the degree of radiographic bone loss (RBL). Selected were 276 patients over 19 years of age to complete the questionnaire for oral health habit and take QLF images, periapical and panoramic radiographs. Oral health habit score, age, and sex showed a statistically significant correlation with FPI. FPI showed a lower value as the oral health habit score increased and the age decreased. Moreover, females showed lower FPI values than did males. RBL showed a statistically significant positive correlation with age but did not show any correlation with oral health habit scores and sex. There was no correlation between FPI and RBL. The results of this study suggest that the clinical use of QLF allows plaque detection by non-invasive procedures and can aid in a more objective estimation for oral hygiene status.

Assessment of White Spots with Quantitative Light-Induced Fluorescence in Patients Undergoing Fixed Orthodontics.

Background:The present study determined white spots with the help of quantitative light-induced fluorescence (QLF) in patients undergoing fixed orthodontics.Materials and Methods:Sixty-four patients undergoing fixed orthodontics above 12 years underwent debonding, and the presence of carious lesion was assessed at baseline and after 6 weeks, 6 months, and 2 years. QLF images were taken with intraoral fluorescence camera. QLF images were examined visually for signs of demineralization, and scoring system was used.Results:It is found that there was fluorescence loss over a period of time. The median sum of fluorescence loss per patient was 55.6% and 29.2% and 101.4% at quartiles at baseline which changed to 51.2% and 26.5% at the first quartile and 101.4% at the second quartile. At 2 years, it was 43.7% and at the first quartile was 22.1% and at the second quartile was 99.1%. There was significant improvement at T2 (P < 0.05), however, between baseline and F1 and between F1 and F2, there was nonsignificant improvement (P > 0.05). The median value for total lesion area per patient was 3.6 mm2 with quartiles 1.2 mm2 and 8.2 mm2 at baseline, 2.6 mm2 with quartiles 0.7 mm2 and 6.3 mm2 at 6 weeks, 2.3 mm2 with quartiles 0.7 mm2 and 6.3 mm2 at 6 months, and 1.8 mm2 with quartiles 0.5 mm2 and 5.8 mm2 at 2 years which was statistically significant (P < 0.05).Conclusion:The authors found that white spots during fixed orthodontic treatment and after debonding is a common phenomenon. Although there was improvement in disappearance of these lesions, complete removal cannot be ensured.

Detection of Dental Caries and Cracks with Quantitative Light-Induced Fluorescence in Comparison to Radiographic and Visual Examination: A Retrospective Case Study.

The aim of this study was to present an optimal diagnostic protocol by comparing and analyzing a conventional examination and the quantitative light-induced fluorescence (QLF) technique. Selected were 297 teeth of 153 patients to take QLF images and bitewing radiographs. Occlusal dental caries, proximal dental caries and cracks were evaluated and scored using QLF, X-ray and/or visual criteria. The sensitivity, specificity, and area under the curve (AUC) of a receiver operating characteristic analysis were calculated. Two fluorescence parameters (|ΔFmax| and ΔRmax) were utilized to evaluate the fluorescence pattern according to the severity of lesions based on QLF or X-ray criteria. QLF showed higher scores for detecting occlusal dental caries and cracks than the conventional method. ΔRmax increased more clearly than ΔFmax did with occlusal dental caries. The |ΔFmax| values of occlusal dental caries, proximal dental caries and cracks showed good AUC levels (0.84, 0.81 and 0.83, respectively). The ΔRmax of occlusal dental caries showed the highest AUC (0.91) and the ΔRmax of proximal dental caries showed a fail level (0.59) compared to bitewing radiographs. The QLF image could visualize and estimate the degree of occlusal dental caries or cracks. Consequently, the QLF technique may be an adjunct tool to conventional methods for the detection of occlusal caries and peripheral cracks.

Histologic analysis of osteonecrosis of the jaw according to the different aspects on quantitative light-induced fluorescence images.

Recurrence of osteonecrosis of the jaw has been reported after surgery. It is therefore necessary to develop a real-time diagnostic method, which can clearly distinguish the surgical margin from unaffected bone. We analyzed a sequestrum from a patient with medication-related osteonecrosis of the jaw (MRONJ). Quantitative light induced fluorescence (QLF) was applied to the sequestrum. In this study, QLF demonstrated three types of fluorescence phenomena (Non-red-fluorescence, hyper-red-fluorescence, and hypo-red-fluorescence) on the sequestrum. Histology revealed geographical, microbiological, and immunological differences based on the fluorescence types on QLF. Non-red-fluorescence showed sclerotic and lamellar bone tissue, hyper-red-fluorescence showed an infectious state due to bacterial invasion and osteolysis, and hypo-red-fluorescence indicated predominantly granular tissue with inflammation, and the absence of bone matrix and bacterial colonies. Based on histologic analysis, we speculated that QLF may be a useful real-time diagnostic tool during surgery for MRONJ. In conclusion, QLF can be useful in distinguishing between lamellar and infected bone, which are visually similar; QLF-guided ONJ surgery, preserving the Non-red-fluorescent areas and removing the hyper- and hypo-red-fluorescent areas of bone may be useful.

Low-Viscosity Resin Infiltration Efficacy on Postorthodontic White Spot Lesions: A Quantitative Light-Induced Fluorescence Evaluation

The aim of this in vivo study was to evaluate the efficacy of low-viscosity light-cured resin infiltration on postorthodontic white spot lesions (WSLs) on incipient and advanced lesions using quantitative light-induced fluorescence (QLF). The study subjects were patients with clinically diagnosed postorthodontic WSLs (n=57). QLF images of the lesions were obtained using a QLF device (Inspektor-Pro, Amsterdam, The Netherlands) before any treatment. Images were processed using the built-in software (QLF patient v2.0.0.48), which produced fluorescence loss (ΔF1), lesion area (Area1), and impact (ΔF1 x Area1, ΔQ1) values. Lesions were categorized as incipient (-5<ΔF1<-12, n=14) or advanced (-12<ΔF1<-25, n=43). They were then infiltrated with low-viscosity resin (Icon-DMG, Hamburg, Germany) according to the manufacturer's instructions. QLF imaging was repeated (ΔF2, Area2, and ΔQ2) from the same aspects assured by the relative software. Kolmogorov-Smirnov, Wilcoxon, and Mann-Whitney tests were used for data evaluation. ΔF1 (-8.40±0.73) and Area1 (3.44±5.19) decreased to -6.58±0.88 and 0.18±0.33 for incipient lesions (p<0.001 and p=0.002, respectively). ΔF1 (-13.20±5.32) and Area1 (4.71±5.56) decreased to -7.51±2.7 and 0.29±1.86 for advanced lesions (p<0.001). When ΔF, lesion area, and ΔQ changes between the groups were compared, the decrease in ΔF was greater for advanced lesions (p<0.001), whereas the decrease in the lesion area and ΔQ was similar (p=0.690, p=0.291). Infiltration treatment provides improvement of WSLs in terms of fluorescence loss, lesion area, and impact for both incipient and advanced lesions, with the latter group presenting higher fluorescence loss reduction.

Enamel demineralization during clear aligner orthodontic treatment compared with fixed appliance therapy, evaluated with quantitative light-induced fluorescence: A randomized clinical trial

The objective of this prospective randomized clinical trial was to investigate the relationship between clear aligner (CA) therapy and the development of white spot lesions and compare it with orthodontic fixed appliance (FA) therapy. This was a prospective randomized clinical trial. The setting was the postgraduate orthodontic clinic at Jordan University of Science and Technology. A total of 49 patients (39 female, 10 male; mean age±standard deviation, 21.25±3years) who required orthodontic treatment with either FAs or CAs were randomly allocated into 1 of 2 study groups. Eligibility criteria included healthy patients of both sexes (age range 17-24years), Class I malocclusion with mild-to-moderate crowding (≤5mm), nonextraction treatment plan, and optimum oral hygiene before treatment as determined by clinical examination. The participants were randomly assigned to a study group according to a simple randomization method using a coin toss by the patient; the text or tail side of the coin indicated treatment with CA (group 1), and the head side of the coin indicated orthodontic treatment with FA (group 2). Blinding was applicable for outcome assessment only. CA therapy was performed for group 1 and FA for group 2. Quantitative light-induced fluorescence (QLF) images were taken before treatment (T0) and 3months later (T1). The QLF images were then analyzed to assess the research outcomes. The main outcome was the mean amount of fluorescence loss (ΔF). Number of newly developed lesions, deepest point in the lesion (ΔFMax), lesion area (pixels), and plaque surface area (ΔR30) were measured as secondary outcomes. Descriptive statistics and comparison within and between groups were calculated. In total, 42 of the 49 participants recruited completed the study (19 in the CA group and 23 in the FA group). The mean amount of fluorescence loss was 0.4% for the CA group (P=0.283) and 1.2% for the FA group (P=0.013). The difference between the 2 groups was significant (confidence interval [CI], -1.8 to -0.4; P=0.002). The mean increase in lesion area was 82.2 pixels for the CA group (P <0.001) and 9.3 pixels for the FA group (P=0.225). The difference between the 2 groups was significant (CI, -117 to -75.0; P<0.001). ΔR30 was 1.2% for the CA group and 10.9% for the FA group (CI, 6.847-12.479; P<0.001). The number of newly developed lesions in the CA group was 6 lesions/patient and 8.25 in the FA group (P=0.039). No serious harm on the oral health of the participants in the 2 study groups was observed other than mild gingivitis associated with plaque accumulation. No serious harm was reported by any of the participants. Orthodontic treatment with CAs and FAs caused enamel demineralization. The CA group developed larger but shallower white spot lesions, whereas the FA group developed more new lesions with greater severity, but they were smaller in area. More plaque accumulation was found in the FA group compared with the CA group. NCT04107012. The protocol was published after trial commencement.

Classification of maturation of bacterial dental deposits using differences in fluorescence intensity

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&lt;0.001), and strong positive correlation was identified between the R/G value and the accumulation of deposits (r = 0.90, p&lt;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.

Assessment of tooth wear based on autofluorescence properties measured using the QLF technology in vitro.

The difference in autofluorescence between enamel and dentine layer has prompted recommendations to use the quantitative light-induced fluorescence (QLF) method for quantifying tooth wear (TW). This study investigated the potential of QLF for distinguishing the severity of occlusal TW based on differences in the autofluorescence intensity. In total, 106 extracted permanent molars and premolars having suspected wear without pulp exposure were used. The severity of wear was determined by visually examining all teeth using the tooth wear index (TWI) of Smith and Knight. QLF images were captured and converted into 8-bit grayscale images. The difference in the fluorescence intensity (ΔG) was calculated by comparing mean grayscale levels between sound and worn areas. Finally, histological examination was conducted by stereomicroscope to confirm the presence of dentine exposure. 100 teeth were included in the final analysis without six teeth having enamel cracks around worn area. The ΔG values increased with the severity of TW as quantified using conventional TWI codes, and differed significantly between the sound and enamel- and dentine-wear teeth (P < 0.001). The histology indicated that enamel remained on 57 teeth, while 43 teeth had dentine-exposed wear and showed significant differences in ΔG compared with enamel-remained teeth. The fluorescence intensity differed significantly depending on the presence of dentine exposure. ΔG could be used to distinguish between sound and enamel- and dentine-wear teeth with a significant correlation. These findings indicate that QLF could be useful for determining the severity of TW of occlusal surfaces noninvasively.