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

Distinguishing discolored caries lesions using biofluorescence and dental bleaching: An in vitro simulation model study

BACKGROUND

Distinguishing between discoloration caused by caries and organic stains is challenging for dentists in clinical settings. Biofluorescence (BF)-bleaching assesses caries lesions by evaluating BF changes after removing organic stains through dental bleaching, leaving cariogenic discoloration. This study aimed to apply BF-bleaching to a simulation model mimicking cariogenic discoloration and compare the BF color changes between organic staining and cariogenic discoloration.

METHODS

Thirty artificial caries lesions in bovine incisors were equally divided into three groups: non-stained (NS), organic-stained (OS), and cariogenic-stained (CS) groups. The specimens were treated with bleaching agent, then BF color of each specimen was evaluated using red BF intensity (ΔR), BF hue angle (h°), and hyperspectral BF spectrum.

RESULTS

The ΔR of CS was approximately 2.74 and 1.73 times higher than that of OS, at baseline and after bleaching for 20 min, respectively. After 20 min of bleaching, the h° of CS increased by approximately 8.1° compared to the baseline, while maintaining the red BF hue range (345‒15°). In contrast, the BF hue of OS shifted from orange (15‒45°) to yellow (45‒75°) simultaneously, and the h° change was approximately 21.9°. Both CS and OS exhibited first emission peaks near 515 nm, and CS showed second peaks in the red range (620‒780 nm). After bleaching, the first peaks were restored to the sound enamel direction (peak at 486 nm), whereas the second peaks of red BF in CS were maintained.

CONCLUSION

Applying BF-bleaching to discolored caries lesions allowed differentiation between cariogenic discoloration and organic staining based on BF color changes.

Telehealth in oral medicine: A cross-sectional evaluation based on a mobile application

BACKGROUND

Teledentistry is considered a good tool in the diagnostic process. In oral medicine, there is a low number of trained professionals and dentists have difficulty in diagnosing and treating oral lesions.

OBJECTIVE

We aimed to perform a cross-sectional evaluation based on the mobile application for oral diagnosis using a mobile application in a Brazilian State.

METHODS

This is a retrospective, cross-sectional, observational study of the data of the "Telehealth in Stomatology in Paraíba" carried out between May 2021 and November 2022.

RESULTS

The app has a team of 16 consultants (Ph.D. professors, postgraduate students, residents, and dentists). In addition, there are 289 registered professionals, with a mean age of 33.7 years, predominantly female (70.2%), working in primary care (79.2%), and general practitioners (42.6%). Regarding the cases, the app has 194 cases, and reactive lesions are the most suggested hypotheses reported by dentists (24.5%) and consultants (22.3%). We had an overall concordance rate of 64.1%.

CONCLUSION

The application is easily accessible and has an assistance network that helps with early diagnosis. In addition, it has good coverage with users in more than 50% of the cities in the state. Thus, applications that provide specialized care to distant areas are important for better public health.

Detection, Diagnosis, and Monitoring of Early Caries: The Future of Individualized Dental Care

Dental caries remains a significant global health issue. It was highlighted by the World Health Organization's 2022 reports that despite the efforts and scientific advancements in caries detection and management, the situation has only marginally improved over the past three decades. The persistence of this problem may be linked to outdated concepts developed almost a century ago but are still guiding dentists' approach to caries management today. There is a need to reconsider professional strategies for preventing and managing the disease. Contemporary dentistry could benefit from embracing new concepts and technologies for caries detection and management. Dentists should explore, among others, alternative methods for caries detection such as optical-based caries detection. These tools have been established for over a decade and they align with current disease understanding and international recommendations, emphasizing early detection and minimally invasive management. This narrative review presents the current state of knowledge and recent trends in caries detection, diagnosis, monitoring, and management, offering insights into future perspectives for clinical applications and research topics.

Photoacoustic imaging of hidden dental caries using visible-light diode laser

BACKGROUND

Hidden caries is a type of tooth decay that is difficult to identify through visual diagnosis because teeth with hidden caries appear normal on the tooth surface but are damaged underneath.

METHODS

A photoacoustic imaging system based on visible light using a diode laser with a wavelength of 532 nm was developed to detect hidden caries in teeth.

RESULTS

The results indicate that the average of acoustic intensity level for healthy teeth is -74.2 ± 0.1 dB, and the average of acoustic intensity range for teeth with hidden caries is -81.2 ± 0.5 dB. The intensity level for the caries area varies depending on the severity of caries.

CONCLUSION

Based on the acoustic intensity level measured by the interaction of teeth with laser light, the photoacoustic imaging system in the study can accurately detect the presence of hidden caries and recognize the difference between caries teeth and healthy teeth. This research can be developed into a prototype of a simple device that makes it easy to operate in dental practice.

Lesion activity assessment of early caries using dye-enhanced quantitative light-induced fluorescence

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 (A3), 5 (A5), and 10 days (A10). For inactive caries, half specimens in each group were remineralized with 2% NaF and reallocated into three groups (I3, I5, and I10, 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.

Surgical Selection of T1 Stage Renal Tumor Resection Based on Imaging MAP Score under Smart Medical Care

Smart medical uses the medical information platform and the current technological means to enable the process of sharing information between medical staff and medical equipment. The combination of current technology and the medical field has become the norm. In the future, more artificial intelligence technologies will be integrated into the medical field to promote the development of medical care. At present, the information on the Internet is very large and complex, and general search engines often do not have knowledge in certain professional fields and can only perform shallow keyword searches. Therefore, it is difficult to meet people's medical diagnosis needs, and smart medical care can solve these needs. Medical imaging refers to the technology or process of obtaining internal tissue images of a certain part of the human body for medical research, including medical imaging systems and medical image processing. Medical image processing refers to the further processing of the obtained images, the purpose of which is either to restore the original image that was not clear enough or to highlight some characteristic information in the image. The purpose of this paper is to study the research on the selection of T1 stage renal tumor resection based on the imaging MAP score under smart medical care. It is hoped that through smart medicine and medical imaging technology, it can help renal tumor resection, reduce the sequelae of renal tumor resection, and promote the development of medical services. This paper proposes applying natural language processing technology to the medical field, creating an intelligent diagnosis assistance system, and using the existing medical record data to realize the corresponding medical assistance functions. It studies the class imbalance problem prevalent in medical datasets and provides better solutions through ensemble learning techniques to improve classifier performance when the number of positive and negative samples is unbalanced. The experimental results in this paper show that the creatinine of patients undergoing renal tumor resection combined with smart medicine and imaging technology is stable at 75 mol/L, while the creatinine is stable at 71 mol/L in other methods. It shows that the postoperative effect of smart medical treatment and imaging technology is better.

Evaluation of dental caries detection with quantitative light-induced fluorescence in comparison to different field of view devices

This study evaluated dental caries detection ability between the Qraycam and Qraypen on the same dental caries lesions. A total of 178teeth from 61patients were imaged using Qraypen C®(QC) and Qraycam Pro®(QP) devices and evaluated using analysis software (QA2). Occlusal, secondary, and proximal dental caries were evaluated and scored according to International Caries Detection and Assessment System(ICDAS II) and X-ray criteria. Bland–Altman plots were used to compare quantitative light-induced fluorescence(QLF) parameters obtained from the different QLF devices. Sensitivity, specificity, and area under the receiver operating characteristic curve(AUROC) were calculated. The ΔF_aver. of the QLF-parameters showed that the mean difference between the two different QLF devices was close to zero and that the ± 5 error value was included in the mean ± 1.96SD range for the detection of dental caries. The accuracies for diagnosing occlusal dental caries were 0.83–0.96 and 0.81–0.82 and the accuracies for diagnosing proximal dental caries were 0.52–0.62 and 0.52–0.71 for the QC and QP devices, respectively. In conclusion, the ΔF_aver. obtained from the QP showed diagnostic value mainly for screening of demineralized teeth. For teeth selected through screening, the depth of the lesion must be precisely evaluated using additional QP and radiographic imaging.

Detection of nosocomial pneumonia pathogens using a fluorescence-based device

BACKGROUND

Early detection of nosocomial pneumonia pathogens is a significant factor in hospital-acquired pneumonia care. This study aimed to determine the autofluorescence properties of five nosocomial pneumonia pathogens using a fluorescence-based device and to establish evidence for clinical guidelines.

METHODS

The following bacterial strains were assessed: Acinetobacter baumannii (AB), Escherichia coli (EC), Enterococcus faecalis (EF), Klebsiella pneumoniae (KP), and Staphylococcus aureus (SA). The bacteria were cultured separately on tryptic soy agar at 37°C under aerobic conditions for 168 h. Fluorescence photographs of each species were captured every 24 h using a fluorescence-based device with fixed camera settings. The images were analyzed by measuring the red and green values (R/G ratio) at a central point in each colony, and the R/G ratios were analyzed using the Kruskal-Wallis non-parametric test.

RESULTS

KP and SA showed red fluorescence with their R/G values, which were significantly higher than those of the other strains (p < 0.001). In particular, the R/G ratio of KP increased steadily until 72 h of incubation, peaking at 3.65. In addition, AB and EC showed orange fluorescence with higher red ratios than green ratios. EF and SA showed green fluorescence all through 168 h of incubation, with R/G values less than 1.0.

CONCLUSIONS

Nosocomial pneumonia pathogens can be identified and classified via bacterial autofluorescence emission. It is possible to develop a rapid and easy-to-use identification technology based on bacterial autofluorescence for clinical applications.

The diagnostic efficacy of quantitative light-induced fluorescence in detection of dental caries of primary teeth

OBJECTIVES

To evaluate a quantitative light-induced fluorescence (QLF) caries detection method using a portable device under clinical conditions and present a QLF scoring index (QS-index) for primary teeth.

METHODS

A total of 878 tooth surfaces (proximal and occlusal) of 44 children were studied. After visual inspection and radiographic examination, images of dental caries captured with the QLF device were classified according to caries progression stages and analyzed with a specialized software. Cut-off values, sensitivity, specificity, and area under the receiver operating characteristic curve (AUROC) were calculated for the QLF parameters: fluorescence loss (ΔF) and bacterial activity (ΔR). The reliability of logistic regression model to combine ΔF and ΔR was evaluated by the AUROC.

RESULTS

QLF parameters showed a good sensitivity (0.72-0.91), specificity (0.74-0.96), and AUROC (0.861-0.940). The AUROC of logistic regression model (0.90-0.957) was higher than ΔF or ΔR average alone in all types of carious lesions. Every level of the QS-index was properly defined to represent the progression of dental caries with corresponding statistical significance.

CONCLUSIONS

The reliability of QLF for dental caries detection in primary teeth was similar to or slightly higher than that of the traditional diagnostic methods of visual inspection or radiographic examination in clinical conditions.

CLINICAL SIGNIFICANCE

The results of QLF were reliable in detecting all types of dental caries in primary teeth. The QLF method can provide visual images as well as quantitatively analyze the carious lesion.

Diagnosis and Management Approaches for Non-cavitated Carious Dental Lesions- A Narrative Review

Background:

Dental caries is one of the most prevalent diseases. Its detection and management should start with a comprehensive treatment plan, with the goals of the elimination of cariogenic bacteria, the reduction of plaque acidogenicity, the encouragement of tooth remineralization, and the repair of damaged teeth.

Objectives:

The aim of this paper was to review the literature regarding the latest updates on the diagnosis and management approaches of non-cavitated carious dental lesions.

Methods:

Studies regarding the diagnosis and management of non-cavitated carious dental lesions were included.

Results:

The subclinical non-cavitated carious lesion might progress to an early enamel lesion, develop into an established dentin lesion, or sometimes end up with a lesion reaching the pulp. The detection and management of caries should be patient-centered, risk-based, and evidence-supported, and should consider the dentists’ expertise and the patients’ needs and preferences. The visual-tactile and radiographic detection of non-cavitated carious lesions are greatly helped by the advances of non-invasive detection tools such as DIAGNOdent, fiber-optic transillumination, quantitative light-induced fluorescence, and DIAGNOcam.

Conclusion:

Accordingly, non-cavitated carious lesions can be arrested by several non-invasive techniques, which are preferred over the invasive options. The clinicians can use sealants plus fluoride varnish on occlusal surfaces, fluoride varnish or resin infiltration on proximal surfaces, and resin infiltration,fluoride gel, or varnish alone on facial or lingual surfaces to manage non-cavitated carious lesions.

Oral health status of inpatients with varying physical activity limitations in rehabilitation wards: A cross-sectional study

Poor oral hygiene can be potentially life-threatening in inpatients. However, no basic protocol on oral hygiene customized for inpatients exists, and lack of oral care related knowledge, attitude, and skills among caregivers could be detrimental to the general health of patients. This study sought to identify the oral care practices and oral health status of inpatients with varying physical activity limitations in a rehabilitation ward.Sixty-one inpatients in a rehabilitation ward were evaluated for their medical and physical conditions and oral health status. These were assessed using the bedside oral exam, decayed, missing, filled teeth index, plaque index, gingival index, and caries activity test.In total, 40 men and 21 women (mean age, 56.6 years) were included in this study. Among them, 50.8% of the patients could brush their teeth unassisted, whereas 49.2% required assistance from an assistant for oral care. The proportion of patients receiving nasogastric tube feeding was higher in the group that could not provide oral self-care; 36.7% and 33.3% of these patients showed moderate and severe dysfunction, respectively, based on bedside oral exam. Scores for the swallowing, tongue, and total domains of bedside oral exam were poorer for patients who could not provide oral self-care (P < .01). The caries activity test indicated a moderate risk for both groups.Our findings suggest that an oral care protocol that considers the physical activity limitations in inpatients in rehabilitation wards is necessary to minimize negative influences on the systemic health of these patients.

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.

Photoacoustic imaging of occlusal incipient caries in the visible and near-infrared range

Purpose

This study aimed to demonstrate the presence of dental caries through a photoacoustic imaging system with visible and near-infrared wavelengths, highlighting the differences between the 2 spectral regions. The depth at which carious tissue could be detected was also verified.

Materials and Methods

Fifteen permanent molars were selected and classified as being sound or having incipient or advanced caries by visual inspection, radiography, and optical coherence tomography analysis prior to photoacoustic scanning. A photoacoustic imaging system operating with a nanosecond pulsed laser as the light excitation source at either 532 nm or 1064 nm and an acoustic transducer at 5 MHz was developed, characterized, and used. En-face and lateral (depth) photoacoustic signals were detected.

Results

The results confirmed the potential of the photoacoustic method to detect caries. At both wavelengths, photoacoustic imaging effectively detected incipient and advanced caries. The reconstructed photoacoustic images confirmed that a higher intensity of the photoacoustic signal could be observed in regions with lesions, while sound surfaces showed much less photoacoustic signal. Photoacoustic signals at depths up to 4 mm at both 532 nm and 1064 nm were measured.

Conclusion

The results presented here are promising and corroborate that photoacoustic imaging can be applied as a diagnostic tool in caries research. New studies should focus on developing a clinical model of photoacoustic imaging applications in dentistry, including soft tissues. The use of inexpensive light-emitting diodes together with a miniaturized detector will make photoacoustic imaging systems more flexible, user-friendly, and technologically viable.

Fluorescence devices for the detection of dental caries

BACKGROUND

Caries is one of the most prevalent and preventable conditions worldwide. If identified early enough then non-invasive techniques can be applied, and therefore this review focusses on early caries involving the enamel surface of the tooth. The cornerstone of caries detection is a visual and tactile dental examination, however alternative methods of detection are available, and these include fluorescence-based devices. There are three categories of fluorescence-based device each primarily defined by the different wavelengths they exploit; we have labelled these groups as red, blue, and green fluorescence. These devices could support the visual examination for the detection and diagnosis of caries at an early stage of decay.

OBJECTIVES

Our primary objectives were to estimate the diagnostic test accuracy of fluorescence-based devices for the detection and diagnosis of enamel caries in children or adults. We planned to investigate the following potential sources of heterogeneity: tooth surface (occlusal, proximal, smooth surface or adjacent to a restoration); single point measurement devices versus imaging or surface assessment devices; and the prevalence of more severe disease in each study sample, at the level of caries into dentine.

SEARCH METHODS

Cochrane Oral Health's Information Specialist undertook a search of the following databases: MEDLINE Ovid (1946 to 30 May 2019); Embase Ovid (1980 to 30 May 2019); US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov, to 30 May 2019); and the World Health Organization International Clinical Trials Registry Platform (to 30 May 2019). We studied reference lists as well as published systematic review articles.

SELECTION CRITERIA

We included diagnostic accuracy study designs that compared a fluorescence-based device with a reference standard. This included prospective studies that evaluated the diagnostic accuracy of single index tests and studies that directly compared two or more index tests. Studies that explicitly recruited participants with caries into dentine or frank cavitation were excluded.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data independently using a piloted study data extraction form based on the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2). Sensitivity and specificity with 95% confidence intervals (CIs) were reported for each study. This information has been displayed as coupled forest plots and summary receiver operating characteristic (SROC) plots, displaying the sensitivity-specificity points for each study. We estimated diagnostic accuracy using hierarchical summary receiver operating characteristic (HSROC) methods. We reported sensitivities at fixed values of specificity (median 0.78, upper quartile 0.90).

MAIN RESULTS

We included a total of 133 studies, 55 did not report data in the 2 x 2 format and could not be included in the meta-analysis. 79 studies which provided 114 datasets and evaluated 21,283 tooth surfaces were included in the meta-analysis. There was a high risk of bias for the participant selection domain. The index test, reference standard, and flow and timing domains all showed a high proportion of studies to be at low risk of bias. Concerns regarding the applicability of the evidence were high or unclear for all domains, the highest proportion being seen in participant selection. Selective participant recruitment, poorly defined diagnostic thresholds, and in vitro studies being non-generalisable to the clinical scenario of a routine dental examination were the main reasons for these findings. The dominance of in vitro studies also means that the information on how the results of these devices are used to support diagnosis, as opposed to pure detection, was extremely limited. There was substantial variability in the results which could not be explained by the different devices or dentition or other sources of heterogeneity that we investigated. The diagnostic odds ratio (DOR) was 14.12 (95% CI 11.17 to 17.84). The estimated sensitivity, at a fixed median specificity of 0.78, was 0.70 (95% CI 0.64 to 0.75). In a hypothetical cohort of 1000 tooth sites or surfaces, with a prevalence of enamel caries of 57%, obtained from the included studies, the estimated sensitivity of 0.70 and specificity of 0.78 would result in 171 missed tooth sites or surfaces with enamel caries (false negatives) and 95 incorrectly classed as having early caries (false positives). We used meta-regression to compare the accuracy of the different devices for red fluorescence (84 datasets, 14,514 tooth sites), blue fluorescence (21 datasets, 3429 tooth sites), and green fluorescence (9 datasets, 3340 tooth sites) devices. Initially, we allowed threshold, shape, and accuracy to vary according to device type by including covariates in the model. Allowing consistency of shape, removal of the covariates for accuracy had only a negligible effect (Chi2 = 3.91, degrees of freedom (df) = 2, P = 0.14). Despite the relatively large volume of evidence we rated the certainty of the evidence as low, downgraded two levels in total, for risk of bias due to limitations in the design and conduct of the included studies, indirectness arising from the high number of in vitro studies, and inconsistency due to the substantial variability of results.

AUTHORS' CONCLUSIONS

There is considerable variation in the performance of these fluorescence-based devices that could not be explained by the different wavelengths of the devices assessed, participant, or study characteristics. Blue and green fluorescence-based devices appeared to outperform red fluorescence-based devices but this difference was not supported by the results of a formal statistical comparison. The evidence base was considerable, but we were only able to include 79 studies out of 133 in the meta-analysis as estimates of sensitivity or specificity values or both could not be extracted or derived. In terms of applicability, any future studies should be carried out in a clinical setting, where difficulties of caries assessment within the oral cavity include plaque, staining, and restorations. Other considerations include the potential of fluorescence devices to be used in combination with other technologies and comparative diagnostic accuracy studies.

Detection of dentin-exposed occlusal/incisal tooth wear using quantitative light-induced fluorescence technology

OBJECTIVES

To prolong tooth life expectancy, tooth wear resulting in dentin exposure should be detected early. However, the most objective methods are clinically limited. We validated fluorescence parameters for distinguishing enamel from dentin-exposed wear in clinical images.

METHODS

Quantitative light-induced fluorescence (QLF) images of 73 adults (age range: 22-48 years, mean: 33.81 ± 7.71 years), including 1949 teeth with varying tooth wear degrees, without restorations, caries, or cusp area fractures, were used to calculate the ΔF_wear values. Areas-of-interest (AOIs) were selected from QLF images; the ΔF_wear values and the tooth wear index (TWI) were calculated for each tooth. The ΔF_wear values were compared according to the TWI scores. The optimum ΔF_wear values for distinguishing enamel and dentin-exposed wear were determined using the receiver operating characteristic (ROC) curve analysis.

RESULTS

Overall, 1949 AOIs were evaluated. The median ΔF_wear values for teeth with TWI scores 0, 1, and 2 (5.7 %, 10.3 %, and 17.0 %) differed significantly (P < 0.001). The optimum cutoff ΔF_wear values were 12.1 and 14.7 in the anterior and posterior teeth, respectively; the corresponding areas under the ROC values (AUROCs) were 0.86 and 0.93 (sensitivity: 0.79 and 0.85; specificity: 0.79 and 0.85, respectively). The ΔF_wear cutoff values for different age groups were within a range (12.7-13.7) and showed high validity (sensitivity, specificity, and AUROC: 0.78, 0.77-0.78, and 0.87-0.88, respectively).

CONCLUSIONS

At the optimum threshold, the ΔF_wear values showed high validity for distinguishing dentin exposure in worn teeth (AUROC: 0.87‒0.93) and could determine pathological tooth wear, particularly in posterior teeth.

CLINICAL SIGNIFICANCE

We demonstrated the feasibility of using QLF to detect dentin-exposed tooth wear and present optimal thresholds according to age. In addition, we confirmed the possibility using such image data for objective and cost-effective epidemiological investigation and application in tele-dentistry.

Development of a Fluorescence-Based Caries Scoring System for an Intraoral Scanner: An in vitro Study

OBJECTIVES

To develop an automated fluorescence-based caries scoring system for an intraoral scanner and totest the performance of the system compared to state-of-the-art methods.

METHODS

Seventy-three permanent posterior teeth were scanned with a three-dimensional (3D) intraoral scanner prototype which emitted light at 415 nm. An overlay representing the fluorescence signal from the tissue was mapped onto 3D models of the teeth. Multiple examination sites (n = 139) on the occlusal surfaces were chosen, and their red and green fluorescence signal components were extracted. These components were used to calculate 4 mathematical functions upon which a caries scoring system for the scanner prototype could be based. Visual-tactile (International Caries Detection and Assessment System, ICDAS), radiographic (ICDAS), and histological assessments were conducted on the same examination sites.

RESULTS

Most index tests showed significant correlation with histology. The strongest correlation was observed for the visual-tactile examination (rs = 0.80) followed by the scanner supported by the caries classification function that quantifies the overall fluorescence compared to sound surfaces (rs = 0.78). Additionally, this function resulted in the highest intra-examiner reliability (κ = 0.964), and the highest sum of sensitivity (SE) and specificity (SP) (sum SE-SP: 1.60-1.84) at the 2 histological levels where the comparison with visual-tactile assessment was possible (κ = 0.886, sum SE-SP = 1.57-1.81) and at the 3 out of 4 histological levels where the comparison with radiographic assessment was possible (κ = 0.911, sum SE-SP = 1.37-1.78); the only exception was for the lesions in the outer third of dentin, where the radiographic assessment showed the highest sum SE-SP (1.78).

CONCLUSION

A fluorescence-based caries scoring system was developed for the intraoral scanner showing promising performance compared to state-of-the-art caries detection methods. The intraoral scanner accompanied by an automated caries scoring system may improve objective caries detection and increase the efficiency and effectiveness of oral examinations. Furthermore, this device has the potential to support reliable monitoring of early caries lesions.

Red fluorescence threshold for assessing the lesion activity of early caries

PURPOSE

The aim of this study was to determine a red fluorescence threshold for differentiating active from inactive non-cavitated carious lesions.

METHODS

Using the Nyvad criteria, 30 human teeth with non-cavitated carious lesions were divided into active lesions (15 teeth) and inactive lesions (15 teeth). Using the blue light of a quantitative light-induced fluorescence-digital camera, the red fluorescence of the lesions was measured as the ΔR value. By live/dead bacterial staining, bacterial viability was calculated as the Ratio_G/G+R. The ΔR and Ratio_G/G+R of active and inactive lesions were compared. The relationship between ΔR and Ratio_G/G+R was also analyzed. The ΔR threshold was determined for the classification of lesion activity, and its validity was tested.

RESULTS

The mean ΔR of active lesions was 1.85 fold higher than that of inactive lesions (p < 0.001), and the Ratio_G/G+R of active lesions was 1.97 fold higher than that of inactive lesions (p < 0.001). There was a significant positive correlation between the ΔR and the Ratio_G/G+R in non-cavitated carious lesions (p < 0.05). The ΔR threshold for the differentiating non-cavitated carious lesions by activity status was 37.55, and the sensitivity and specificity were both 83.33 %.

CONCLUSIONS

A red fluorescence threshold for categorizing non-cavitated carious lesion activity based on microbial metabolic activity was determined. Accurate evaluation of the activity status of non-cavitated carious lesions will assist in diagnosis and treatment planning for patients with dental caries.

Photodynamic inactivation using a chlorin-based photosensitizer with blue or red-light irradiation against single-species biofilms related to periodontitis

Chlorin-e6 (Ce6), as a photosensitizer (PS), has demonstrated significant reduction of microorganisms' viability when irradiated by red light. However, the main absorption peak of this PS is located at blue light spectrum, which is less investigated. This study aimed to evaluate the effect of pure-chlorin-e6-mediated photodynamic inactivation (PDI) using different light sources (450 or 660 nm) against biofilms related to periodontitis. Streptococcus oralis, Fusobacterium nucleatum, Porphyromonas gingivalis, and Aggregatibacter actinomycetemcomitans single-species biofilms were developed under proper conditions for five days. PDI was performed using different concentrations of Ce6 (100 and 200 mM), wavelengths (450 and 660 nm) and comparisons were made after colony forming unit and confocal laser scanning microscopy (CLSM) analysis. The use of light and PS were also individually tested. The greatest bacterial elimination was observed in the group where PDI was employed with blue light and concentration of 200 mM for all bacterial strains tested (4.01 log₁₀ for A. actinomycetemcomitans, and total elimination for P. gingivalis and S. oralis), except for F. nucleatum, where 3.46 log₁₀ reduction was observed when red light and 200 mM Ce6 were applied (p < 0.05). The antimicrobial effects of PDI mediated by Ce6 for all single pathogenic biofilms were confirmed by live/dead staining under CLSM analysis. For all single-species biofilms, the use of PDI mediated by chlorin-e6 photosensitizer under blue or red-light irradiation (450 and 660 nm) demonstrated a significant reduction in bacterial viability, but blue light showed a promising higher photobiological effect, encouraging its adjuvant use to basic periodontitis treatment.

Monitoring enamel caries on resin-treated occlusal surfaces using quantitative light-induced fluorescence: an in vitro study

The aim of this study is to evaluate the ability of quantitative light-induced fluorescence (QLF) to monitor enamel caries lesions of different severity stages located on the occlusal surfaces of permanent teeth before and after treatment with resin infiltrant. Sixty extracted permanent teeth had one occlusal site selected and were categorized according to the International Caries Detection and Assessment System (ICDAS) criteria. The teeth were divided into three groups (n = 20): ICDAS 1, ICDAS 2, and ICDAS 3. The teeth were assessed by a trained examiner using QLF in two phases: (A) before and (B) after treatment with resin infiltrant. The caries lesions were evaluated using the following QLF parameters: area (mm²); ΔF, fluorescence loss (%); and ΔQ, fluorescence loss integrated over the lesion area (%*mm²). The resin infiltrant (Icon™) was applied on the occlusal surface following the manufacturer's recommendations. The teeth were then sectioned and prepared for polarized light microscopy analysis. The penetration of resin infiltrant was measured with ImageJ. The groups showed a statistically significant difference in all QLF parameters before and after caries infiltration, with the reduction of fluorescence values posttreatment (p < 0.05). Infiltrant penetration was observed in all groups, with a statistical difference between all groups (p < 0.05). The reduction in QLF parameters after resin infiltration suggests that QLF is able to monitor enamel caries lesions of different severity stages located on the occlusal surfaces of permanent teeth before and after treatment with resin infiltrant.

Susceptibility of oral bacteria to antibacterial photodynamic therapy

Effective methods for managing the oral microbiome are necessary to ensure not only the oral but also the systemic health of a human body. The purpose of this study was to determine the sensitivity of four photosensitizers (PSs) to blue light in six representative oral bacterial species that cause intraoral diseases. The following six strains were investigated: Actinomyces israelii, Enterococcus faecium, Fusobacterium nucleatum, Lactobacillus gasseri, Streptococcus mutans, Veillonella parvula. PS stock solutions (1 mg/ml) were prepared by dissolving curcumin and protoporphyrin-IX in dimethyl sulfoxide, and resazurin and riboflavin in distilled water. The inoculation of 20 ml of a bacterial suspension cultured for 24 hours was mixed with 1,980 ml of each test solution, and then a light source was placed in front of the mixture. The irradiation wavelength was 405 nm and its applied energy was 25.3 J. The independent-samples t-test and one-way analysis of variance within groups were performed to compare the antibacterial effects in the four PSs. The antibacterial susceptibility when using different PSs and visible blue-light irradiation differed between the bacterial strains. Antibacterial photodynamic therapy that includes light exposure and PSs can be used to control the oral bacteria strains related to oral disease.

Application of quantitative light-induced fluorescence technology for tooth bleaching treatment and its assessment: An in vitro study

OBJECTIVES

This study aimed to determine the efficacy of a combination of photocatalysts-hydrogen peroxide at a low concentration (3.5%) and titanium dioxide (TiO₂)-activated at a wavelength of 405 nm using quantitative light-induced fluorescence (QLF) technology, and to quantify their tooth-bleaching efficacy using fluorescence images obtained from QLF technology.

MATERIALS AND METHODS

Forty bovine incisors were extrinsically stained according to Stookey's method, and were randomly divided into four groups (n = 10 per group). Two bleaching solutions were prepared by mixing 3.5% H₂O₂ with 0.05% of anatase and rutile TiO₂ powders. These solutions were applied to the stained teeth using a microbrush and then irradiated for 15 min at either 306 or 405 nm to activate the bleaching agent. The color difference (ΔE^*) was assessed before and after every 5 min of treatment. The ΔE^* and the changes in the fluorescence loss (ΔΔF) were obtained from white-light and fluorescence images, respectively.

RESULTS

All of the low-H₂O₂/TiO₂ treatments caused significant tooth-bleaching efficacy after irradiation at 306 and 405 nm (p < 0.05). The results did not differ significantly between the two wavelengths (p > 0.05), but the bleaching efficacy was greater with anatase TiO₂ at 306 nm and rutile TiO₂ at 405 nm. Analysis of the fluorescence images revealed that the ΔF values increased significantly in all groups with the treatment time (p < 0.05). There was a statistically significant correlation between ΔE^* and the change in ΔΔF (r = 0.822, p < 0.001).

CONCLUSIONS

Combining low-H₂O₂/TiO₂ with QLF technology at 405 nm has an efficacy of tooth-bleaching as a less harmful and biofriendly method, while the fluorescence images obtained by QLF technology could be used to assess tooth-bleaching.

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 (ΔE_F) and white-light (ΔE_W) 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). ΔE_F was significantly larger than ΔE_W 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.