Detection of pit and fissure sealant microleakage using quantitative light-induced fluorescence technology: an in vitro study

This in vitro study aimed to evaluate the feasibility of quantitative light-induced fluorescence (QLF) technology for detecting the presence and severity of microleakage of pit and fissure sealants. The areas of interest (AOIs) were 160 pits and fissures of 40 extracted permanent teeth. Fluorescent images were acquired using a QLF device, and the maximum fluorescence loss ΔFmax of each AOI was analyzed. After staining and cross-sectioning of the teeth, histological dye penetration was scored on a scale of 0 to 3. The relationship between ΔFmax and microleakage depth was analyzed, and the areas under the curve (AUCs) were calculated. The │ΔFmax│ increased as microleakage depth increased. The ΔFmax values of microleakage areas showed a strong significant correlation with the histological scores of dye penetration (r = - 0.72, P = 0.001). AUC analysis showed a high diagnostic accuracy for microleakage depth (AUC = 0.83-0.91). The highest AUC of 0.91 was found when differentiating the outer half microleakage of the sealant (histological score 0 vs. 1-3). QLF technology is effective in assessing the presence and severity of microleakage, suggesting its potential for noninvasive detection and monitoring of sealant microleakage in clinical settings.

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

OBJECTIVES

Evaluating 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.

METHODS

Red 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.

RESULTS

Significant 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.

CONCLUSIONS

This 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.

Quantitative light-induced fluorescence-guided surgery for medication-related osteomyelitis of the jaw

BACKGROUND

Medication-related osteonecrosis of the jaw (MRONJ) is a challenging condition with increasing incidence, and the lack of clear surgical guidelines poses difficulties in its treatment.

METHODS

Quantitative light-induced fluorescence (QLF), which can distinguish between vital and necrotic bone tissue without the need for additional markers, was used to guide minimally invasive surgery in a 75-year-old patient with MRONJ.

RESULTS

This study demonstrated that QLF allows the real-time identification of infected and necrotic bone tissue during surgery, enabling precise and minimally invasive resection. We observed spontaneous bone recovery and remodeling in sclerotic bone areas that exhibited autofluorescence using a QLF device, suggesting its potential for preserving the bone tissue.

CONCLUSION

This study highlights the promising application of QLF as a valuable photodiagnostic tool in MRONJ surgery, offering a noninvasive and intraoperative device for differentiating pathological bone tissue. This approach can potentially improve the precision of surgical interventions and contribute to improved patient outcomes in MRONJ management.

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

BACKGROUND

Owing 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.

METHODS

Overall, 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.

RESULTS

Using 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.

CONCLUSION

The 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.

Quantitative light-induced fluorescence enables effective detection of orthodontic adhesive residues in diverse environments

BACKGROUND

Adhesive remnants post-orthodontic treatment might have deleterious effects on oral health, including enamel demineralization, plaque accumulation, and elevated risk of caries development. The aim of this study was to identify and characterize adhesive residues in an ex vivo environment rich in salivary microbiota using quantitative light-induced fluorescence (QLF) technology.

METHODS

Disc-shaped adhesive samples with thickness ranging from 800 to 100 µm were prepared using GC Ortho, GOTO, T Orthobond, and Transbond XT and subsequently evaluated utilizing a QLF system. Bovine teeth containing GC Ortho and GOTO adhesives and isolated human premolar teeth bonded with brackets were subjected to a 10-day incubation in an artificial saliva environment. Daily imaging was conducted using QLF during incubation. Data with ΔR > 30% and simple hygiene score (SHS) were obtained with a software for further analysis.

RESULTS

Fluorescence intensity exhibited significant differences among the four orthodontic adhesives (p < 0.05). Results of incubation in artificial saliva revealed that red fluorescence surrounding the adhesive on the tooth surface was distinctly observable from day five onwards, with ΔR > 30% and SHS levels higher than those of the control group without adhesive (p < 0.05). Observation of fluorescence images of isolated human premolar teeth with bonded brackets indicated that red fluorescence was primarily present around the brackets.

CONCLUSIONS

Application of QLF is efficacious in identifying and demarcating adhesive residues within an environment rich in salivary microbiota.

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

BACKGROUND

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.

AIMS

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.

SETTINGS AND DESIGN

This was an in vivo explorative study.

MATERIALS AND METHODS

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.

STATISTICAL ANALYSIS

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.

RESULTS

A statistically significant correlation was found between the visual assessment scoring and the QLF image analysis for the evaluation of tongue coating.

CONCLUSION

The Digital QLF tongue imaging system was found to be reliable due to its correlation with the clinical score and objective nature.

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.

High-throughput field phenotyping reveals genetic variation in photosynthetic traits in durum wheat under drought

Chlorophyll fluorescence (ChlF) is a powerful non-invasive technique for probing photosynthesis. Although proposed as a method for drought tolerance screening, ChlF has not yet been fully adopted in physiological breeding, mainly due to limitations in high-throughput field phenotyping capabilities. The light-induced fluorescence transient (LIFT) sensor has recently been shown to reliably provide active ChlF data for rapid and remote characterisation of plant photosynthetic performance. We used the LIFT sensor to quantify photosynthesis traits across time in a large panel of durum wheat genotypes subjected to a progressive drought in replicated field trials over two growing seasons. The photosynthetic performance was measured at the canopy level by means of the operating efficiency of Photosystem II ( Fq'/Fm' ) and the kinetics of electron transport measured by reoxidation rates ( Fr1' and Fr2' ). Short- and long-term changes in ChlF traits were found in response to soil water availability and due to interactions with weather fluctuations. In mild drought, Fq'/Fm' and Fr2' were little affected, while Fr1' was consistently accelerated in water-limited compared to well-watered plants, increasingly so with rising vapour pressure deficit. This high-throughput approach allowed assessment of the native genetic diversity in ChlF traits while considering the diurnal dynamics of photosynthesis.

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.

Quantitative light-induced fluorescence as a potential tool for detection of enamel chemical composition

BACKGROUND

Little is known about how the chemical composition of enamel affects the optical properties of teeth, but advances in technology allow this to be studied using white-light and fluorescent images. This study aimed to identify the variation in enamel chemical composition that may affect tooth optical properties, such as tooth color and autofluorescence.

METHODS

Sixty-one specimens of extracted human molars were prepared. Raman spectrometry was used to assess chemical composition of enamel, and tooth color, and autofluorescence from enamel were evaluated by quantitative light-induced fluorescence (QLF) images. Pearson correlation and multiple linear regression analyses were used.

RESULTS

Enamel fluorescence was related to enamel composition rather than tooth color. The b* value from the fluorescence image had a moderate correlation with crystallinity (full-width at half-maximum: r = -0.433, p < 0.001) and laser-induced fluorescence intensity (r = 0.450, p < 0.001) from Raman spectroscopy. In multiple linear regression analysis, the chemical composition of the tooth had a significant effect on the b* value from the fluorescent image (R² = 0.433, p < 0.001). In contrast, tooth color values (L*, a*, and b*) were not correlated with chemical composition.

CONCLUSIONS

The present study revealed that enamel autofluorescence in QLF was related to chemical composition of the enamel, particularly the inorganic‒organic interface. While enamel chemical composition can be detected only in a laboratory environment, enamel fluorescence by QLF may enable estimation in a dental clinic, which has implications for the field of tooth bleaching or esthetic restorative materials.

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.

Methods of assessment of early dentine erosion: a review

Dentine erosion is an increasingly recognised problem, especially in aging population, and various methods have been utilised for its assessment. This narrative review was planned to summarise the methods for the assessment of the early stages of dentine erosion. Relevant original articles published in the English language from 2013 to 2017 were reviewed. Laboratory techniques and methods with in vivo potential were separately studied. It is evident that the assessment of early dentine erosion is complex and requires a combination of methods. For clinical evaluation, chemical analysis and optical methods show great potential but are in need of more validation.