In vitro investigation of fluorescence of carious dentin observed with a Soprolife® camera

A Fluorescence-based Method to Reaccess Root Canals in Endodontically Treated Teeth: A Micro-Computed Tomography Tridimensional Assessment

INTRODUCTION

The aim of this study was to evaluate the volume of dentin removal and the volume of remnants of restorative material after the removal of an esthetic restorative coronal set and cervical barrier in endodontically treated mandibular molars with the aid of different magnification methods using 3-dimensional (3D) micro-computed tomographic (micro-CT) morphometric analysis.

METHODS

A sample of 30 mandibular first molars (N = 30) was used. All teeth were endodontically treated, and the specimens were initially scanned using micro-CT imaging and reconstructed. The molars were filled by a single-cone technique, and immediately the material at the initial 2-mm cervical level was removed. Cervical barriers were confected using ionomer glass cement with fluorescein 0.1%, filling the 2 mm at the cervical level of the canals and an additional 2 mm as the base. The coronal restoration set was performed using esthetic resin composites. A simulated tooth aging process was performed with 20,000 thermocycling cycles. The sample was distributed into the following 3 groups (n = 10) for the removal of the restoration set and cervical barrier with diamond burs based on the magnification aid: no magnification aid (naked eye), operative microscope aid, and REVEAL device (Design for Vision Inc, Bohemia, NY) aid. After removal, the final 3D micro-CT scanning and reconstruction were conducted with the same parameters as the initial scanning, and superposition of the final and initial scanning was performed. Morphometric analysis was conducted using CTAn software (Bruker microCT, Kontich, Belgium) to assess the volume of remnant restorative material (mm³), the volume of dentin removal (mm³), and the direction and site of dentin removal. Data were analyzed using 1-Way analysis of variance (P < .05).

RESULTS

The REVEAL group showed better results regarding the volume of remnant material (3.17 ± 1.65) and the percentage of dentin removal (2.56 ± 1.34). The microscope group showed no statistical difference compared with the REVEAL group regarding dentin removal (3.30 ± 1.48) and was statistically similar to the naked eye group in the volume of remnant material (9.63 ± 4.33). The naked eye group showed the worst results for the volume of remnant material (7.60 ± 2.68) and the percentage of dentin removal (6.60 ± 3.70).

CONCLUSIONS

The use of fluorescence associated with magnification was the method that presented the best results, with lower percentages of dentin removal and smaller volumes of remaining restorative material. This is an innovative technology in endodontics that shows potential to overcome the challenge of reaccessing root canals in the context of endodontic retreatment.

Development of a Visualisation Approach for Analysing Incipient and Clinically Unrecorded Enamel Fissure Caries Using Laser-Induced Contrast Imaging, MicroRaman Spectroscopy and Biomimetic Composites: A Pilot Study

This pilot study presents a practical approach to detecting and visualising the initial forms of caries that are not clinically registered. The use of a laser-induced contrast visualisation (LICV) technique was shown to provide detection of the originating caries based on the separation of emissions from sound tissue, areas with destroyed tissue and regions of bacterial invasion. Adding microRaman spectroscopy to the measuring system enables reliable detection of the transformation of the organic–mineral component in the dental tissue and the spread of bacterial microflora in the affected region. Further laboratory and clinical studies of the comprehensive use of LICV and microRaman spectroscopy enable data extension on the application of this approach for accurate determination of the boundaries in the changed dental tissue as a result of initial caries. The obtained data has the potential to develop an effective preventive medical diagnostic approach and as a result, further personalised medical treatment can be specified.

The performance of SoproLIFE for early detection of coronal caries using the International Caries Classification and Management System - A preliminary laboratory-based study

The aim of this laboratory-based study is to evaluate performance of the Light-Induced Fluorescence Evaluator (SoproLIFE) for early detection of coronal caries and to validate the findings using the International Caries Classification and Management System (ICCMS). A total of 56 freshly extracted teeth with coronal carious lesions were included. 74 regions of interest were identified. Visual assessments with International Caries Detection and Assessment Systems (ICDAS), radiographic information and SoproLIFE images were used to classify each region of interest according to the ICCMS as a reference standard. SoproLIFE specificity and sensitivity were calculated at the sound-enamel and dentine lesion levels. Inter and intra reproducibility of ICDAS were analysed and showed a moderate agreement (0.52) and (0.58) respectively. At the sound-initial caries level, the sensitivity and specificity for the SoproLIFE were 90.0%, 95.8% respectively, whilst for the dentine caries level, sensitivity was 100% with specificity of 53.8%. A low proportion of teeth with dental caries were classified as caries-free using the SoproLIFE (false negative=10%). As a conclusion, the performance of SoproLIFE was promising in distinguishing between early enamel carious lesions and sound surfaces. This detection tool could be suggested to be used with ICCMS to assist in the clinical decision-making process.

The Efficacy of Soprolife® in Detecting in Vitro Remineralization of Early Caries Lesions

Objectives

This randomized controlled in vitro 4-arm trial study aimed to evaluate the efficacy of SoproLife^® in detecting and quantifying in vitro remineralization with early caries lesions.

Material and Methods

Sixty human teeth were randomly assigned into four equal groups. Groups 1 and 2 were prophylactically cleaned; groups 3 and 4 were not. Group 1 received treatment with MI Varnish^® and Recaldent™ for 30 days. Group 2 was treated similarly, but without MI Varnish^®. Group 3 was treated as 1 and Group 4 as 2. Mineral composition was obtained using scanning electron microscopy with energy dispersive X-ray analysis SoproLife^® camera images on the occlusal surfaces were analysed for grey value distribution and difference in mean intensity values (DI). Paired t-test and Mann-Whitney-U test were used for intragroup comparison between baseline and T1. Kruskal-Wallis followed by Mann-Whitney-U tests were used for inter-group comparisons at T1.

Results

All groups exhibited a significant increase in calcium content and calcium-to-phosphorus ratio (P < 0.05), except Group 4 (Group 1 showed the greatest increase, then Groups 3 and 2). Grey intensity values decreased in all groups (P < 0.05). Group 1 showed the greatest change in DI (16.82 [SD 12.07]), followed by Group 3 (12.46 [SD 9.41]), 2 (10.45 [SD 7.76]), and 4 (6.46 [SD 6.21]). The difference in DI was different between the compared groups (P = 0.038); Groups 1 and 3 exhibited a greater DI compared with 4 (P < 0.01).

Conclusions

Within the limitations of this study, SoproLife^® is effective for early detection and for longitudinally monitoring the remineralization after Recaldent™ therapy.

Relationship between Changes in Chemical Composition of Enamel Subsurface Lesions and the Emitted Nonlinear Optical Signals: An in vitro Study

The development of new diagnostic technologies based on the light scattering and autofluorescence properties of dental tissues is required to improve the diagnostic ability of initial caries lesions earlier than previously done and promoting the potential of treatment without surgical intervention. The aim of this study is to correlate fluorescence-based results provided by multiphoton microscopy (MPM) with confocal Raman microscopy records using phosphate level at 960 cm-1 and the organic matrix at ∼2,931 cm-1 in healthy and demineralized human enamel. Measurements on 14 teeth were made using two incident lights of different wavelengths, released by confocal Raman microscopy and MPM. Raman phosphate peak intensity at 960 cm-1 along with organic to mineral ratio at (2,931/430 cm-1) and nonlinear optical signals (second harmonic generation [SHG] and intrinsic two-photon excited fluorescence [I2PEF]) were recorded from the demineralized and healthy enamel sites. Raman spectral maps showed that the higher the organic/mineral ratio in the demineralized enamel, the lower the intensity of mineral component in the same zone. MPM revealed new optical indicators of carious lesion as shown by the presence of a red-shifted fluorescence peak in the 650- to 750-nm area of the fluorescence spectrum of demineralized enamel. Moreover, on sample regions with insignificant autofluorescence, the emergence of the SHG signal could be noted. By comparing I2PEF images with the structural motifs observed by the confocal Raman imaging system, the morphological similarity of the acquired images was quite evident. Any change in the I2PEF spectra reflects alterations in the chemical composition of enamel. These findings may provide an important basis for potentially valuable applications of photonic tools in the clinical diagnosis of tooth pathological conditions, besides exposing the fundamental role of organic matrix in enamel integrity and reparation.

Diagnostic Performance of Different Methods in Detecting Incipient Non-Cavitated Occlusal Caries Lesions in Permanent Teeth

Aim: This in vitro study was aimed to investigate the performance of the new caries detection tools on the incipient occlusal caries. Study design: In our study, 100 permanent molar teeth, which were considered to have incipient, enamel caries (D1 and D2 threshold values) according to ICDAS II score. After the visual examination, caries measurements have been applied to all teeth by using DIAGNOdent pen (DP), CarieScan PRO (CP) and SoproLife camera (SC). In addition, in vitro examinations were repeated 2 weeks later. After sectioning and evaluation in stereomicroscope, the lesion depth was determined with histological criteria that are accepted for the gold standard for this research. Sensitivity, specificity, accuracy and area under the ROC curve were calculated at D1 and D2 thresholds. The intra-examiners' reproducibility were analysed using Cohen's kappa statistics and intraclass correlation coefficient (ICC). Results: Intra-examiner repeatability values varied from 0.94 to 0.99 and kappa values ranged from 0.90 to 0.99. While the highest sensitivity and specificity value showed for SC at D1 and D2 thresholds, CP presented the lowest values. The area under ROC curves (Az) varied from 0.70 to 0.99. ICDAS II showed the highest area under ROC curves (Az). Conclusions: ICDAS II, visual diagnostic method by itself is considered to sufficient in order to diagnose incipient occlusal caries. SC may be used as an alternative method for the ICDAS II, since its advantages by displaying caries lesion on the computer monitor, follow-up and motivation of the patients provided.

Preliminary study assessing remineralisation of early caries on posterior teeth using SoproLife®

PURPOSE

The aim of this study was to assess the effectiveness of minimal intervention via fluoride therapy in management of early caries lesion with the aid of SoproLife®.

MATERIALS AND METHODS

A total of 40 patients were recruited, (mean age = 23 years) and were assigned to low and moderate caries risk groups (n = 20). Eighty occlusal surfaces of posterior teeth were examined for early caries lesion visually and using SoproLife® at baseline and at a recall visit six months later. At baseline visit, patients were given oral hygiene education, fluoridated toothpaste for homecare and topical fluoride application. SoproLife® images acquired were analysed using Image J software version 1.50. Difference in the mean value of intensity of the red wavelength spectrum between baseline and recall visits, (ΔI), were analysed for both risk groups. ΔI for upper and lower first molar teeth were also analysed.

RESULTS

Results show no statistical difference for ΔI between low and moderate risk groups (p = 0.13). There is no statistical difference in ΔI within the low caries risk group (p = 0.42) but there is significant difference in the moderate risk group (p = 0.02). No statistically significant difference in ΔI value between upper first molars (UFM) (p = 0.80) and lower first molars (LFM) (p = 0.07) were detected. There was also no statistically significant difference in ΔI value within the upper and lower first molars (UFM: p = 0.31, LFM: p = 0.27).

CONCLUSION

SoproLife® generated images did not show significant differences in remineralisation of early caries between low and moderate caries risk patients and between the upper first and lower first permanent molars in these patients.

Fossilization transforms vertebrate hard tissue proteins into N-heterocyclic polymers

Vertebrate hard tissues consist of mineral crystallites within a proteinaceous scaffold that normally degrades post-mortem. Here we show, however, that decalcification of Mesozoic hard tissues preserved in oxidative settings releases brownish stained extracellular matrix, cells, blood vessels, and nerve projections. Raman Microspectroscopy shows that these fossil soft tissues are a product of diagenetic transformation to Advanced Glycoxidation and Lipoxidation End Products, a class of N-heterocyclic polymers generated via oxidative crosslinking of proteinaceous scaffolds. Hard tissues in reducing environments, in contrast, lack soft tissue preservation. Comparison of fossil soft tissues with modern and experimentally matured samples reveals how proteinaceous tissues undergo diagenesis and explains biases in their preservation in the rock record. This provides a target, focused on oxidative depositional environments, for finding cellular-to-subcellular soft tissue morphology in fossils and validates its use in phylogenetic and other evolutionary studies.

Multiphoton Microscopy for Caries Detection with ICDAS Classification

Dentin carious lesion is a dynamic process that involves demineralization and collagen denaturation. Collagen type I is the major protein in dentin and it has been investigated based on its optical properties. Multiphoton microscopy (MPM) is a nonlinear imaging technique that reveals the caries process using the collagen two-photon excitation fluorescence (2PEF) and its second-harmonic generation (SHG). Combining the histological and the International Caries Detection and Assessment System (ICDAS) classifications with nonlinear optical spectroscopy (NLOS), 2PEF and SHG intensities of enamel and dentin were highly altered during the caries process. It has been proven that the ratio SHG/2PEF is a relevant indicator of the organic matrix denaturation [Terrer et al.: J Dent Res 2016; 96: 574-579]. In the present study, a series of measurable signals is made to detect early stages of carious lesion according to the ICDAS classification and to explore the relationship between these measures and the ICDAS scale. Comparison of the efficiency of nonlinear optical signals for caries detection with the ICDAS classification is essential to evaluate their potential for clinical application. In our study, the use of the NLOS measured by MPM allowed us to monitor a quantitative parameter (SHG/2PEF ratio) according to the dentin carious lesion state (ICDAS and histological examination). Three coherent new groups were defined (ICDAS 0/1; ICDAS 2/3; ICDAS 4/5/6), where the carious process can be clearly described with a statistically significant decrease of the SHG/2PEF ratio.

One-step partial or complete caries removal and bonding with antibacterial or traditional self-etch adhesives: study protocol for a randomized controlled trial

BACKGROUND

Current concepts in conservative dentistry advocate minimally invasive dentistry and pulp vitality preservation. Moreover, complete removal of carious dentin in deep carious lesions often leads to pulp exposure and root canal treatment, despite the absence of irreversible pulp inflammation. For years, partial caries removal has been performed on primary teeth, but little evidence supports its effectiveness for permanent teeth. Furthermore, the recent development of new antibacterial adhesive systems could be interesting in the treatment of such lesions. The objectives of this study are to compare the effectiveness of partial versus complete carious dentin removal in deep lesions (primary objective) and the use of an antibacterial versus a traditional two-step self-etch adhesive system (main secondary objective).

METHODS/DESIGN

The DEep CAries Treatment (DECAT) study protocol is a multicenter, randomized, controlled superiority trial comparing partial versus complete caries removal followed by adhesive restoration. The minimum sample size required is 464 patients. Two successive randomizations will be performed (allocation ratio 1:1): the first for the type of excavation (partial versus complete) and the second (if no root canal treatment is required) for the type of adhesive (antibacterial versus traditional). For the two objectives, the outcome is the success of the treatment after 1 year, measured according to a composite outcome of five FDI criteria: material fracture and retention, marginal adaptation, radiographic examination (including apical pathologies), postoperative sensitivity and tooth vitality, and carious lesion recurrence.

DISCUSSION

The study will investigate the interest of a conservative approach for the management of deep carious lesions in terms of dentin excavation and bioactive adhesive systems. The results may help practitioners achieve the most efficient restorative procedure to maintain pulp vitality and increase the restoration longevity.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT02286388 . Registered in November 2014.

Porphyrin and Pentosidine Involvement in the Red Fluorescence of Enamel and Dentin Caries

Proper treatment of dental caries demands detection of carious lesions at an early stage and a minimal invasive cavity preparation to preserve the maximum tooth structure. Various devices use fluorescence for caries detection via recording the red fluorescence generated by dentin caries under illumination.

The aim of this study was to evaluate the porphyrin and pentosidine involvement in the red fluorescence observed in enamel and dentin caries when illuminated with the Soprolife® camera (Sopro, Acteon Group, La Ciotat, France) and Vistacam® camera (Dürr Dental AG, Bietigheim-Bissingen, Germany). Three techniques were used: single photon fluorescence spectroscopy, micro-Raman spectroscopy, and color analysis with ImajeJ software. Cross-sections of human teeth, scored from 0–6 with the International Caries Detection and Assessment System (ICDAS), were examined by fluorescence microscopy. Teeth spectra of each ICDAS score were compared with those of protoporphyrin IX (PpIX), porphyrin I, and pentosidine solutions. A specific confocal Raman microscopy analysis was realized and a Red–Green–Blue model analysis of Soprolife® images was performed using ImageJ software to compare the color variations on ICDAS score 1 and 2. Fluorescence spectroscopy and micro-Raman spectroscopy revealed the presence of PpIX in carious enamel and dentin. The clinical relevance of this experimentation was that the increased knowledge of the fluorescence aids for caries detection could improve the preventive approach, thus reducing the operative one.

How to cite this article

Slimani A, Nouioua F, Panayotov I, Giraudeau N, Chiaki K, Shinji Y, Cloitre T, Levallois B, Gergely C, Cuisinier F, Tassery H. Porphyrin and Pentosidine Involvements in the Red Fluorescence of Enamel and Dentin Caries. Int J Experiment Dent Sci 2016;5(1):1-10.

Detecting Short-Term Changes in the Activity of Caries Lesions with the Aid of New Technologies

This paper discusses the use of new technologies for the assessment of caries and more in particular changes in caries activity. Over the past decades, we have seen a shift from restorative treatment caries to a prevention-driven approach. Also there is a need for shorter and less expensive caries clinical trials. These demand earlier detection of lesions and the monitoring of lesion changes longitudinally in time, which has led to the development of new technologies to aid clinical visual examination. Also clinical visual inspection indices have been refined to fit this purpose. There is a constant flow of technologies emerging and disappearing. This review discusses the merits of recent developments regarding their respective uses for research purposes in testing new caries prevention strategies as well as in clinical caries management in dental private practice. Which technique to choose highly depends on the needed resolution of information.

Decrease in fluorescence lifetime by glycation of collagen and its application in determining advanced glycation end-products in human dentin

Advanced Glycation End-products (AGEs) are produced by the Maillard reaction, which causes cross-linking of collagen and results in changes in the mechanical properties of collagen tissues. Several types of AGE fluoresce, and measurement of this fluorescence is effective for determining the presence of AGEs. Because fluorescence intensity by steady-state fluorometry is affected by sample surface condition and light source, we focused on fluorescence lifetime measurement (FLM). We found that fluorescence lifetime of collagen gel decreased with glycation progress. In vivo application of FLM for determination of AGEs was confirmed in human dentin.