An Experimental Review of Optical Coherence Tomography Systems for Noninvasive Assessment of Hard Dental Tissues.

Optical coherence tomography (OCT) is a noninvasive, high-resolution, cross-sectional imaging technique. To date, OCT has been demonstrated in several areas of dentistry, primarily using wavelengths around 1,300 nm, low numerical aperture (NA) imaging lenses, and detectors insensitive to the polarization of light. The objective of this study is to compare the performance of three commercially available OCT systems operating with alternative wavelengths, imaging lenses, and detectors for OCT imaging of dental enamel. Spectral-domain (SD) OCT systems with (i) 840 nm (Lumedica, OQ LabScope 1.0), (ii) 1,300 nm (Thorlabs, Tel320) center wavelengths, and (iii) a swept-source (SS) OCT system (Thorlabs OCS1300SS) centered at 1,325 nm with optional polarization-sensitive detection were used. Low NA (0.04) and high NA (0.15) imaging lenses were used with system (iii). Healthy in vivo and in vitrohuman enamel and eroded in vitro bovine enamel specimens were imaged. The Tel320 system achieved greater imaging depth than the OQ LabScope 1.0, on average imaging 2.6 times deeper into the tooth (n = 10). The low NA lens provided a larger field of view and depth of focus, while the high NA lens provided higher lateral resolution and greater contrast. Polarization-sensitive imaging eliminated birefringent banding artifacts that can appear in conventional OCT scans. In summary, this study illustrates the performance of three commercially available OCT systems, objective lenses, and imaging modes and how these can affect imaging depth, resolution, field of view, and contrast in enamel. Users investigating OCT for dental applications should consider these factors when selecting an OCT system for clinical or basic science studies.

A yellowness index for use in dentistry.

OBJECTIVES: To develop an equation that predicts the perceptual yellowness of teeth. METHODS: A large set of new psychophysical yellowness data were generated from an experiment where 500 participants each ranked a set of 58 shade guide samples. Two existing equations (WIO and b*) and one new equation (YIO) were evaluated by comparing their values for the 58 shade guide tabs with the psychophysical data. Coefficient of determination (r2), '% wrong decisions', and STRESS were used as measures of performance. The YIO equation was optimized using these data to maximize the r2 value. A validation set of psychophysical data was prepared in an experiment where 40 participants each ranked 5 sets of 9 samples that were viewed on an emissive display. The candidate equations were evaluated using these data and the r2, %WD, and STRESS metrics. RESULTS: All three metrics YIO, WIO and b* were strongly correlated with perceptual yellowness. YIO and WIO both showed stronger correlation than b*. CONCLUSIONS: A new yellowness equation YIO has been developed to correlate with tooth yellowness. It is suggested that tooth yellowness and whiteness are highly related concepts.

Feasibility of a Real-Time Clinical Augmented Reality and Artificial Intelligence Framework for Pain Detection and Localization From the Brain.

BACKGROUND: For many years, clinicians have been seeking for objective pain assessment solutions via neuroimaging techniques, focusing on the brain to detect human pain. Unfortunately, most of those techniques are not applicable in the clinical environment or lack accuracy. OBJECTIVE: This study aimed to test the feasibility of a mobile neuroimaging-based clinical augmented reality (AR) and artificial intelligence (AI) framework, CLARAi, for objective pain detection and also localization direct from the patient's brain in real time. METHODS: Clinical dental pain was triggered in 21 patients by hypersensitive tooth stimulation with 20 consecutive descending cold stimulations (32°C-0°C). We used a portable optical neuroimaging technology, functional near-infrared spectroscopy, to gauge their cortical activity during evoked acute clinical pain. The data were decoded using a neural network (NN)-based AI algorithm to classify hemodynamic response data into pain and no-pain brain states in real time. We tested the performance of several networks (NN with 7 layers, 6 layers, 5 layers, 3 layers, recurrent NN, and long short-term memory network) upon reorganized data features on pain diction and localization in a simulated real-time environment. In addition, we also tested the feasibility of transmitting the neuroimaging data to an AR device, HoloLens, in the same simulated environment, allowing visualization of the ongoing cortical activity on a 3-dimensional brain template virtually plotted on the patients' head during clinical consult. RESULTS: The artificial neutral network (3-layer NN) achieved an optimal classification accuracy at 80.37% (126,000/156,680) for pain and no pain discrimination, with positive likelihood ratio (PLR) at 2.35. We further explored a 3-class localization task of left/right side pain and no-pain states, and convolutional NN-6 (6-layer NN) achieved highest classification accuracy at 74.23% (1040/1401) with PLR at 2.02. CONCLUSIONS: Additional studies are needed to optimize and validate our prototype CLARAi framework for other pains and neurologic disorders. However, we presented an innovative and feasible neuroimaging-based AR/AI concept that can potentially transform the human brain into an objective target to visualize and precisely measure and localize pain in real time where it is most needed: in the doctor's office. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR1-10.2196/13594.

European Organization for Caries Research Workshop: Methodology for Determination of Potentially Available Fluoride in Toothpastes.

Toothpastes are the most universally accepted form of fluoride delivery for caries prevention. To provide anti-caries benefits, they must be able to release fluoride during the time of tooth brushing or post brushing into the oral cavity. However, there is no standard accepted procedure to measure how much fluoride in a toothpaste may be (bio) available for release. The European Organization for Caries Research proposed and supported a workshop with experts in fluoride analysis in toothpastes and representatives from industry. The objective of the workshop was to discuss issues surrounding fluoride analysis in toothpaste and reach consensus on terminology and best practices, wherever the available evidence allowed it. Participants received a background paper and heard presentations followed by structured discussion to define the problem. The group also reviewed evidence on the validity, reliability and feasibility of each technique (namely chromatography and fluoride electroanalysis) and discussed their strengths and limitations. Participants were able to reach a consensus on terminology and were also able to identify and summarize the advantages and disadvantages of each technique. However, they agreed that most currently available methods were developed for regulatory agencies several decades ago, utilizing the best available data from clinical trials then, but require to be updated. They also agreed that although significant advances to our understanding of the mechanism of action of fluoride in toothpaste have been achieved over the past 4 decades, this clearly is an extraordinarily complex subject and more work remains to be done.

Evaluation of colorimetric indices for the assessment of tooth whiteness.

OBJECTIVES: To evaluate the performance of existing equations that measure perceptual whiteness of teeth. METHODS: Three new psychophysical experiments were conducted and combined with two previously published experiments to form a large set of data to test performance of whiteness indices. Three whiteness indices (WIC, WIO, WID,) were compared with regard to their ability to measure perceived whiteness. Coefficient of determination (r2) and '% wrong decisions' were used as measures of performance. One of the new experiments involved 500 participants across five different countries to explore the effect of gender, age and culture on whiteness perception. RESULTS: Equations (WIO and WID) that have been optimized for use with tooth whiteness better correlated with visual perceptions of changes in tooth whiteness than the more general CIE whiteness index (WIC). The best performance was given by WIO (in terms of both r2 and % wrong decisions). No effect of age, gender or culture was found on whiteness perception. CONCLUSIONS: WIO is a robust method for assessing whiteness of human teeth.

Automatic detection and classification of dental fluorosis in vivo using white light and fluorescence imaging.

OBJECTIVES: To assess a novel method of automatic fluorosis detection and classification from white light and fluorescent images. METHODS: Dental images from 1,729 children living in two fluoridated and two non-fluoridated UK cities were utilised. A novel detection and classification algorithm was applied to each image and TF scores were obtained using thresholding criteria. These were compared to clinical reference standard images. Comparisons between reference and automated assessments were undertaken to record correct and incorrect classifications and the ability of the system to separate the fluoridated and non-fluoridated populations. RESULTS: The automated system performed well and was able to differentiate the two populations (P < 0.0001) to the same degree as the reference standard. When using the highest score from the clinical assessment the agreement between automated and clinical assessments was 0.56 (Kappa SE = 0.0160, p < 0.0001). CONCLUSIONS: Assessment of dental fluorosis is typically undertaken by clinical examiners in epidemiological studies. The training and calibration of such examiners is complex and time consuming and the assessments are subject to bias - frequently because of the examiner's awareness of the water fluoridation status of subjects. The use of remote scoring using photographs has been advocated but still requires trained examiners. This study has shown that image-processing methodologies applied to white light and fluorescent images could automatically score fluorosis and statistically separate fluoridated and non-fluoridated areas. The system requires further refinement to manage confounding factors such as the presence of non-fluoride opacities and tooth stain.

Digital epidemiology - Calibrating readers to score dental images remotely.

BACKGROUND: There is growing interest to use digital photographs in dental epidemiology. However, the reporting of procedures and metric-based performance outcomes from training to promote data quality prior to actual scoring of digital images has not been optimal. METHODS: A training study was undertaken to assess training methodology and to select a group of scorers to assess images for dental fluorosis captured during the 2013-2014 National Health and Nutrition Examination Survey (NHANES). Ten examiners and 2 reference examiners assessed dental fluorosis using the Deans Index (DI) and the Thylstrup-Fejerskov (TF) Index. Trainees were evaluated using 128 digital images of upper anterior central incisors at three different periods and with approximately 40 participants during two other periods. Scoring of all digital images was done using a secured, web-based system. RESULTS: When assessing for nominal fluorosis (apparent vs. non-apparent), the unweighted Kappa for DI ranged from 0.68 to 0.77 and when using an ordinal scale, the linear-weighted kappa for DI ranged from 0.43 to 0.69 during the final evaluation. When assessing for nominal fluorosis using TF, the unweighted Kappa ranged from 0.67 to 0.89 and when using an ordinal scale, the linear-weighted kappa for TF ranged from 0.61 to 0.77 during the final evaluation. No examiner improvement was observed when a clinical assessment feature was added during training to assess dental fluorosis using TF, results using DI was less clear. CONCLUSION: Providing examiners theoretical material and scoring criteria prior to training may be minimally sufficient to calibrate examiners to score digital photographs. There may be some benefit in providing an in-person training to discuss criteria and review previously scored images. Previous experience as a clinical examiner seems to provide a slight advantage at scoring photographs for DI, but minimizing the number of scorers does improve inter-examiner concordance for both DI and TF.

Red fluorescence imaging for dental plaque detection and quantification: pilot study.

The red fluorescence of dental plaque originating from porphyrins in oral bacteria may allow visualization, detection, and scoring of plaque without disclosing agents. Two studies were conducted. The first included 24 healthy participants who abstained from oral hygiene for 24 h. Dental plaque was collected from tooth surfaces, and a 10% solution was prepared. These were scanned by a molecular spectrometer to identify the optimum excitation and emission wavelengths of plaque for developing a red fluorescence imaging system. Fourteen healthy subjects completed the second study. After a washout period (1 week), participants had a prophylaxis at baseline and abstained from oral hygiene during the study. They were monitored using the fluorescence imaging system at baseline, 24 h, and 48 h. A dentist clinically assessed plaque after disclosing and on red fluorescence images. Three descriptors were extracted from images and a RUSBoost classifier derived computer fluorescence scores through cross-validation. Red fluorescence plaque levels increased during the 48-h accumulation. Plaque progression was identified by dentist assessment and computer analysis, presenting significant differences between visits at tooth and subject levels (p<0.05). Moderate correlations showed between clinical plaque and red fluorescence plaque (r=0.62 dentist, r=0.55 computer). The best agreement was observed when disclosing plaque threshold at level 2, for both dentist evaluation (sensitivity 71.1%, specificity 67.7%, accuracy 70.2%) and computer classification (sensitivity 68.4%, specificity 62.9%, accuracy 67.1%). Given the correlation with clinical diagnosis, red fluorescence imaging shows its potential for providing an objective and promising method for proper oral hygiene assessment.

Role of microbial biofilms in the maintenance of oral health and in the development of dental caries and periodontal diseases. Consensus report of group 1 of the Joint EFP/ORCA workshop on the boundaries between caries and periodontal disease.

BACKGROUND AND AIMS: The scope of this working group was to review (1) ecological interactions at the dental biofilm in health and disease, (2) the role of microbial communities in the pathogenesis of periodontitis and caries, and (3) the innate host response in caries and periodontal diseases. RESULTS AND CONCLUSIONS: A health-associated biofilm includes genera such as Neisseria, Streptococcus, Actinomyces, Veillonella and Granulicatella. Microorganisms associated with both caries and periodontal diseases are metabolically highly specialized and organized as multispecies microbial biofilms. Progression of these diseases involves multiple microbial interactions driven by different stressors. In caries, the exposure of dental biofilms to dietary sugars and their fermentation to organic acids results in increasing proportions of acidogenic and aciduric species. In gingivitis, plaque accumulation at the gingival margin leads to inflammation and increasing proportions of proteolytic and often obligately anaerobic species. The natural mucosal barriers and saliva are the main innate defence mechanisms against soft tissue bacterial invasion. Similarly, enamel and dentin are important hard tissue barriers to the caries process. Given that the present state of knowledge suggests that the aetiologies of caries and periodontal diseases are mutually independent, the elements of innate immunity that appear to contribute to resistance to both are somewhat coincidental.

Prevention in practice--a summary.

BACKGROUND: This paper is a summary document of the Prevention in Practice Conference and Special Supplement of BMC Oral Health. It represents the consensus view of the presenters and captures the questions, comments and suggestions of the assembled audience. METHODS: Using the prepared manuscripts for the conference, collected materials from scribes during the conference and additional resources collated in advance of the meeting, authors agreed on the summary document. RESULTS: The Prevention in Practice conference aimed to collate information about which diseases could be prevented in practice, how diseases could be identified early enough to facilitate prevention, what evidence based therapies and treatments were available and how, given the collective evidence, could these be introduced in general dental practice within different reimbursement models. CONCLUSIONS: While examples of best practice were provided from both social care and insurance models it was clear that further work was required on both provider and payer side to ensure that evidence based prevention was both implemented properly but also reimbursed sufficiently. It is clear that savings can be made but these must not be overstated and that the use of effective skill mix would be key to realizing efficiencies. The evidence base for prevention of caries and periodontal disease has been available for many years, as have the tools and techniques to detect, diagnose and stage the diseases appropriately. Dentistry finds itself in a enviable position with respect to its ability to prevent, arrest and reverse much of the burden of disease, however, it is clear that the infrastructure within primary care must be changed, and practitioners and their teams appropriately supported to deliver this paradigm shift from a surgical to a medical model.

Toothpaste prevents debonded brackets on erosive enamel.

UNLABELLED: This study evaluated the effect of high fluoride dentifrice on the bond strength of brackets after erosive challenge. Eighty-four enamel specimens were divided into seven groups (n = 12): WN (distilled water/no acid challenge), W3C (distilled water/3 cycles of acid challenge), and W6C (distilled water/6 cycles of acid challenge) were not submitted to dentifrice treatment. Groups RF3C (regular fluoride dentifrice/3 cycles of acid challenge) and RF6C (regular fluoride dentifrice/6 cycles of acid challenge) were treated with dentifrices containing 1450 µg F(-)/g and HF3C (high fluoride dentifrice/3 cycles of acid challenge) and HF6C (high fluoride dentifrice/6 cycles of acid challenge) were with 5000 µg F(-)/g. Acid challenges were performed for seven days. After bond strength test, there was no significant difference among groups submitted to 3 cycles of acid challenge (P > 0.05). Statistically significant difference was found between the regular and high fluoride dentifrices after 6 cycles of acid challenge (<0.05). Similar areas of adhesive remaining were found among control groups and among groups W6C, RF3C, RF6C, HF3C, and HF6C. The high fluoride dentifrice was able to prevent the reduction of bond strength values of brackets submitted to acid challenge. CLINICAL RELEVANCE: the high fluoride toothpaste prevents debonded brackets on erosive enamel.

The elderly as a market--challenges to evidence.

OBJECTIVE: To review the role of the oral care industry in the oral health of elders and opportunities for partnership with other key stakeholders. BACKGROUND: The elder population is growing at a faster rate than any other segment of the population. This is coupled with a greater probability of maintaining the dentition into later life and an increase in complex restorative work. If an elder's situation changes, they are highly vulnerable to a rapid onset of oral disease that can be devastating and extremely difficult to address. MATERIALS AND METHODS: This manuscript reviews the role of the oral care industry in understanding this population as a market and the different approaches that might be used in promoting health. RESULTS: Two key market segments were identified, the vulnerable elders with high levels of chronic oral disease, systemic complications, medications and often inability to maintain good standards of oral hygiene and a wealthier, health and beauty conscious group with a keen interest in maintaining a healthy, aesthetically pleasing and functional dentition throughout their lives. CONCLUSIONS: It is likely that within current healthcare models, the oral care of elders will be unsustainable, with a smaller working population funding ever-increasing health care needs. 'Home care' combined with effective professional preventive and effective therapeutic options are essential. Partnerships between the oral care industry and oral care providers, to deliver education and engagement of care workers, medical practitioners, pharmacists and social services, are essential over the next few decades.

The Seattle Care Pathway for securing oral health in older patients.

There is a need for a structured, evidence based approach to care for older dental patients. The following article describes the development of the Seattle Care Pathway based upon a workshop held in 2013. An overview is provided on the key issues of older persons dental care including the demography shift, the concept of frailty, the need for effective prevention and treatment to be linked to levels of dependency and the need for a varied and well educated work force. The pathway is presented in tabular form and further illustrated by the examples in the form of clinical scenarios. The pathway is an evidence based, pragmatic approach to care designed to be globally applicable but flexible enough to be adapted for local needs and circumstances. Research will be required to evaluate the pathways application to this important group of patients.

High-fluoride toothpaste: a multicenter randomized controlled trial in adults.

OBJECTIVE: The aim of this single - blind, multicenter, parallel, randomized controlled trial was to evaluate the effectiveness of the application of a high-fluoride toothpaste on root caries in adults. METHODS: Adult patients (n = 130, ♂ = 74, ♀ = 56; mean age ± SD: 56.9 ± 12.9) from three participating centers, diagnosed with root caries, were randomly allocated into two groups: Test (n = 64, ♂ = 37, ♀ = 27; lesions = 144; mean age: 59.0 ± 12.1; intervention: high-fluoride toothpaste with 5000 ppm F), and Control (n = 66, ♂ = 37, ♀ = 29; lesions = 160; mean age: 54.8 ± 13.5; intervention: regular-fluoride toothpaste with 1350 ppm F) groups. Clinical examinations and surface hardness scoring of the carious lesions were performed for each subject at specified time intervals (T0 - at baseline before intervention, T1 - at 3 months and T2 - at 6 months after intervention). Mean surface hardness scores (HS) were calculated for each patient. Statistical analyses comprised of two-way analysis of variance and post hoc comparisons using the Bonferroni-Dunn correction. RESULTS: At T0 , there was no statistical difference between the two groups with regard to gender (P = 0.0682, unpaired t-test), or age (P = 0.9786, chi-squared test), and for the overall HS (Test group: HS = 3.4 ± 0.61; CONTROL GROUP: HS = 3.4 ± 0.66; P = 0.8757, unpaired t-test). The anova revealed significantly better HS for the test group than for the control groups (T1 : Test group: HS = 2.9 ± 0.67; CONTROL GROUP: HS = 3.1 ± 0.75; T2 : Test group: HS = 2.4 ± 0.81; CONTROL GROUP: HS = 2.8 ± 0.79; P < 0.0001). However, the interaction term time-point*group was not significant. CONCLUSIONS: The application of a high-fluoride containing dentifrice (5000 ppm F) in adults, twice daily, significantly improves the surface hardness of otherwise untreated root caries lesions when compared with the use of regular fluoride containing (1350 ppm F) toothpastes.

Non-surgical management methods of noncavitated carious lesions.

OBJECTIVE: To critically appraise all evidence related to the efficacy of nonsurgical caries preventive methods to arrest or reverse the progression of noncavitated carious lesions (NCCls). METHODS: A detailed search of Medline (via OVID), Cochrane Collaboration, Scielo, and EMBASE identified 625 publications. After title and abstract review, 103 publications were selected for further review, and 29 were finally included. The final publications evaluated the following therapies: fluorides (F) in varying vehicles (toothpaste, gel, varnish, mouthrinse, and combination), chlorhexidine (CHX) alone or in combination with F, resin infiltration (I), sealants (S), xylitol (X) in varying vehicles (lozenges, gum, or in combination with F and/or xylitol), casein phosphopeptide amorphous calcium phosphate (CPP-ACP) or in combination with calcium fluoride phosphate. All included studies were randomized clinical trials, were conducted with human subjects and natural NCCls, and reported findings that can yield outcomes measures such as caries incidence/increments, percentage of progression and/or arrest, odds ratio progression test to control, fluorescence loss/mean values, changes in lesion area/volume and lesion depth. Data were extracted from the selected studies and checked for errors. The quality of the studies was evaluated by three different methods (ADA, Cochrane, author's consensus). RESULTS: Sample size for these trials ranged between 15 and 3903 subjects, with a duration between 2 weeks and 4.02 years. More than half of the trials assessed had moderate to high risk of bias or may be categorized as 'poor'. The great majority (65.5%) did not use intention to treat analysis, 21% did not use any blinding techniques, and 41% reported concealment allocation procedures. Slightly more than half of the trials (55%) factored in background exposure to other fluoride sources, and only 41% properly adjusted for potential confounders. CONCLUSIONS: Fluoride interventions (varnishes, gels, and toothpaste) seem to have the most consistent benefit in decreasing the progression and incidence of NCCls. Studies using xylitol, CHX, and CPP-ACP vehicles alone or in combination with fluoride therapy are very limited in number and in the majority of the cases did not show a statistically significant reduction. Sealants and resin infiltration studies point to a potential consistent benefit in slowing the progression or reversing NCCls.

Effect of post-brushing mouthwash solutions on salivary fluoride retention--study 1.

OBJECTIVE: The aim of the present study was to evaluate the effects on post-brushing salivary F retention of rinsing with mouthwashes containing either 500 or 225 ppm F compared to not rinsing. METHODS: The study was a randomized, investigator-blind, cross-over trial with three treatment arms. Thirty volunteers brushed with 0.5 g of 1450 ppm F paste for 40 seconds and then spat out the waste slurry. They then rinsed for one minute with 10 mL of their allocated mouthwash or they did not rinse after the brushing. Saliva samples were collected before brushing (0 minutes) and at one, three, five, 10, 20, 30, 45, and 60 minutes after brushing. The subjects were not allowed to speak, eat, or drink during these 60-minute test periods. The F levels in saliva were then calculated for each time point and the integrated area under the curve calculated (AUC0-60). RESULTS: The mean AUCs were 626, 380, and 237 for the 500 ppm F, 225 ppm F, and no rinse treatments, respectively, and all pair-wise comparisons were statistically significant (p < 0.01). CONCLUSION: It is concluded that rinsing with either 500 or 225 ppm F mouthwash significantly increases the level of F in saliva compared to not rinsing after brushing with 1450 ppm F toothpaste. The 500 ppm F mouthwash provided a significant increase in F retention compared to the 225 ppm F rinse (p = 0.001).

Evaluating the use of fluorescent imaging for the quantification of dental fluorosis.

BACKGROUND: The quantification of fluorosis using fluorescence imaging (QLF) hardware and stain analysis software has been demonstrated in selected populations with good correlation between fluorescent image metrics and TF Index scores from photographs. The aim of this study was to evaluate the ability of QLF to quantify fluorosis in a population of subjects (aged 11-13) participating in an epidemiological caries and fluorosis survey in fluoridated and non-fluoridated communities in Northern England. METHODS: Fluorescent images of the maxillary incisors were captured together with standardized photographs were scored blind for fluorosis using the TF Index. Subjects were excluded from the analysis if there were restorations or caries on the maxillary central incisors. RESULTS: Data were available for 1774 subjects (n=905 Newcastle, n=869 Manchester). The data from the fluorescence method demonstrated a significant correlation with TF Index scores from photographs (Kendall's tau = 0.332 p<0.0001). However, a number of additional confounding factors such as the presence of extrinsic stain or increased enamel translucency on some subjects without fluorosis or at low levels of fluorosis severity had an adverse impact on tooth fluorescence and hence the outcome variable. This in conjunction with an uneven distribution of subjects across the range of fluorosis presentations may have resulted in the lower than anticipated correlations between the fluorescent imaging metrics and the photographic fluorosis scores. Nevertheless, the fluorescence imaging technique was able to discriminate between a fluoridated and non-fluoridated population (p<0.001). CONCLUSIONS: Despite confounding factors the fluorescence imaging system may provide a useful objective, blinded system for the assessment of enamel fluorosis when used adjunctively with photographic scoring.

Histological validation of near-infrared reflectance multispectral imaging technique for caries detection and quantification.

Near infrared (NIR) multispectral imaging is a novel noninvasive technique that maps and quantifies dental caries. The technique has the ability to reduce the confounding effect of stain present on teeth. The aim of this study was to develop and validate a quantitative NIR multispectral imaging system for caries detection and assessment against a histological reference standard. The proposed technique is based on spectral imaging at specific wavelengths in the range from 1000 to 1700 nm. A total of 112 extracted teeth (molars and premolars) were used and images of occlusal surfaces at different wavelengths were acquired. Three spectral reflectance images were combined to generate a quantitative lesion map of the tooth. The maximum value of the map at the corresponding histological section was used as the NIR caries score. The NIR caries score significantly correlated with the histological reference standard (Spearman's Coefficient=0.774, p<0.01). Caries detection sensitivities and specificities of 72% and 91% for sound areas, 36% and 79% for lesions on the enamel, and 82% and 69% for lesions in dentin were found. These results suggest that NIR spectral imaging is a novel and promising method for the detection, quantification, and mapping of dental caries.