Near-IR and CP-OCT imaging of suspected occlusal caries lesions.

INTRODUCTION: Radiographic methods have poor sensitivity for occlusal lesions and by the time the lesions are radiolucent they have typically progressed deep into the dentin. New more sensitive imaging methods are needed to detect occlusal lesions. In this study, cross-polarization optical coherence tomography (CP-OCT) and near-IR imaging were used to image questionable occlusal lesions (QOC's) that were not visible on radiographs but had been scheduled for restoration on 30 test subjects. METHODS: Near-IR reflectance and transillumination probes incorporating a high definition InGaAs camera and near-IR broadband light sources were used to acquire images of the lesions before restoration. The reflectance probe utilized cross-polarization and operated at wavelengths from 1,500 to 1,700 nm where there is an increase in water absorption for higher contrast. The transillumination probe was operated at 1,300 nm where the transparency of enamel is highest. Tomographic images (6 × 6 × 7 mm3 ) of the lesions were acquired using a high-speed swept-source CP-OCT system operating at 1,300 nm before and after removal of the suspected lesion. RESULTS: Near-IR reflectance imaging at 1,500-1,700 nm yielded significantly higher contrast (P < 0.05) of the demineralization in the occlusal grooves compared with visible reflectance imaging. Stains in the occlusal grooves greatly reduced the lesion contrast in the visible range yielding negative values. Only half of the 26 lesions analyzed showed the characteristic surface demineralization and increased reflectivity below the dentinal-enamel junction (DEJ) in 3D OCT images indicative of penetration of the lesion into the dentin. CONCLUSION: This study demonstrates that near-IR imaging methods have great potential for improving the early diagnosis of occlusal lesions. Lasers Surg. Med. 49:215-224, 2017. © 2017 Wiley Periodicals, Inc.

Effectiveness of Air Drying and Magnification Methods for Detecting Initial Caries on Occlusal Surfaces Using Three Different Diagnostic Aids.

Objective-The aim of this study was to assess the effect of magnification and air-drying on detection of carious lesion. Study Design-44 human extracted premolars were selected with sound occlusal surfaces without frank cavitation. The Diagnostic techniques used were Unaided visual examination, Magnifying Loupes (4.2×) and Stereomicroscope (10×, before and after air-drying) and then the teeth were sectioned bucco-lingually and both the surfaces were examined under Stereomicroscope (50×) to assess the presence or absence of carious lesion in the pit and fissures. The scores were compared to obtain Cohen's kappa coefficient (Reproducibility) and subjected to the Friedman Test and Paired t test. Sensitivity, specificity and positive predictive value used to assess accuracy. Results-On Statistical analysis, visual examination before and after air drying had highest specificity but lowest sensitivity compared to different diagnostic techniques. Magnifying loupes after air-drying had highest sensitivity and lowest specificity compared to other diagnostic techniques. Conclusion-Air drying combined with magnifying aids are cost-effective, reliable method for detection of early carious lesion. If used in pediatric clinical practice, any undesirable pain and discomfort to the patient due to invasive procedures and helps in employing preventive measures.

Micro X-ray computed tomography of pits and fissures.

BACKGROUND: Most tooth cavities start to develop inside pits and fissures where brushing, saliva, fluoride toothpaste or mouthwashes have no access. Therefore, 3D morphology of pits and fissures is an important subject to be studied in relation to maintaining proper oral hygiene. OBJECTIVE: This study aimed to present high resolution images of pits and fissures in human teeth using a laboratory-based micro X-ray Computed Tomography (mXCT) and also to present the basic structure evaluation that could be obtained. METHODS: Three human wisdom teeth were examined. Two different set-ups were used in this study achieving resolution of 14.59 µm (Field of View of 14.9 mm) and resolution of 4.43 µm (FOV of 4.5 mm) respectively. Automated segmentation was performed for further evaluation to distinguish between empty space (pits and fissures) and the filled space (enamel). RESULTS: The 3D tomography results demonstrate detailed morphology with accurate dimensions and the locations of the pits and fissures, which is important to investigate the relationship with tooth decay that mostly starts deep inside pits and fissures. CONCLUSIONS: Segmentation from the mXCT imaging of pits and fissures provides obvious visual evidence to help in promotion of oral health and to improve personal tooth care in preventive treatment protocols.

In vitro evaluation of the Spectra early caries detection system.

OBJECTIVE: The goal of this study was to perform an in vitro evaluation of the Spectra, a new caries detector that uses light-induced fluorescence of healthy tooth structure and bacterial pigments to optically detect caries. The Spectra generates a storable color map image of examined tooth surfaces which shows areas of enamel and dentin caries. In this study, Spectra readings of occlusal surfaces were compared to clinical, radiographic, and histological assessments of caries. METHODS: Two examiners evaluated 41 extracted molars. The teeth were radiographed and then visually assessed. The International Caries Detection and Assessment System (ICDAS) was used to classify the extent of caries. The teeth were then sectioned and assigned a histological score based on the extension of caries into enamel or dentin. RESULTS: Teeth lacking radiographic caries had a mean Spectra reading of 1.5. Teeth having radiographic caries had a mean Spectra reading of 2.0. This difference was statistically significant. In general, higher ICDAS scores were associated with higher Spectra readings. Teeth with histologically evident deep dentin caries had significantly higher Spectra readings than intact teeth or teeth with superficial enamel demineralization. Spectra assessment of occlusal caries agrees with clinical and radiographic methods. CONCLUSION: Spectra images illustrate the full spectrum of caries severity, from enamel demineralization to dentin decay. The Spectra is a promising technology for the diagnosis and for monitoring the progression of occlusal caries.

Clinical diagnosis of fissure caries with conventional and laser-induced fluorescence techniques.

We studied the in vivo validity of dentinal fissure caries diagnosis by visual examination, bitewing radiography, and use of a laser-induced fluorescence device (DIAGNOdent). A total of 144 and second molars with macroscopically intact occlusal surfaces in 41 Chinese young adults were examined visually, by bitewing radiography, and by DIAGNOdent. Visual examination after pit and fissure opening was used as the reference standard. The sensitivity and specificity of detecting caries that had extended into the dentin were, respectively, 0.89 and 0.44 by visual detection of opacity or discoloration after air drying, 0.13 and 1.00 by bitewing radiography to detect radiolucency extending into the dentin, and 0.70 and 0.84 by DIAGNOdent testing with a cut-off score of 40. Caries detection by a combination of visual examination and DIAGNOdent had a sensitivity of 0.67 and specificity of 0.94. Receiver operating characteristic analysis showed that this combined approach was superior to the other methods.

Occlusal fissures in equine cheek teeth: µCT and histological findings.

Fissures on the occlusal surface of equine cheek teeth are commonly encountered during oral examination. Generally, their presence is considered abnormal but their aetiopathogenesis and clinical impact on pulp disease is still undetermined. The aims of this research were to study the extent of occlusal cheek teeth fissures using high-resolution X-ray computed tomography (µCT) imaging and their histological characteristics. Twenty-seven teeth (of 15 horses) were scanned using µCT imaging to analyse fissure extent. Histological examination of a subset of teeth (n=7) was performed. Forty-three type 1 fissures (35 type 1a, eight type 1b) were identified. The mean length of the fissure of type 1a and type 1b on the occlusal surface was 3.47+/-1.60mm and 13.64+/-7.40mm, respectively. Their mean depth was 13.22+/-10.76mm and 7.42+/-6.42mm, respectively. Potential risk factors associated with fissure depth were identified using a multivariable mixed model The location of the fissure and Triadan number were significantly associated with fissure depth. Fissures could be identified on histological sections with the presence of organic material inside the fissure, microorganisms in the continuation of the fissure extending into the dentinal tubules and the presence of reactionary dentine. This study suggests that fissures can provide a pathway for microorganisms to enter the dentinal tubules, potentially resulting in local pulpal inflammation. It appears that in healthy teeth, vital odontoblasts react by producing reactionary (tertiary) dentin, which lacks patent tubules and thus provides a proper seal.

Clinical performance of a new laser fluorescence device for detection of occlusal caries lesions in permanent molars.

OBJECTIVES: To determine the clinical performance of a laser fluorescence device (DIAGNOdent pen, KaVo) to discriminate between different occlusal caries depths (D(0)-D(1-4); D(0-2)-D(3,4)) in permanent molars. METHODS: In this prospective, randomized two-centre-study 120 sound/uncavitated carious sites in 120 patients were measured after visual and radiographic caries assessment. In cases of operative intervention (n=86), the lesion depths after caries removal were recorded (reference). In cases of preventive intervention (n=34), the sites were reassessed visually/radiographically after 12 months to verify the status assessed before (reference). The discrimination performance was determined statistically (Mann-Whitney test, Spearman's rho coefficient, and areas under the receiver operating characteristic curves (AUCs)). Sensitivities (SE) and specificities (SP) were plotted as a function of the measured values and cut-off values for the mentioned thresholds suggested. RESULTS: Sound sites (n=13) had significantly minor fluorescence values than carious sites (n=107) (P<0.0001) as had sites with no/enamel caries (n=63) compared to dentinal caries (n=57). The AUCs for the same discriminations were 0.92 and 0.78 (P<0.001). For the D(0)-D(1-4) threshold, a cut-off at a value of 12 (SE: 0.88, SP: 0.85) and for the D(0-2)-D(3,4) threshold at 25 (SE: 0.67, SP: 0.79) can be suggested. A moderate positive correlation between the measurements and the caries depths was calculated (rho=+0.57, P=0.01). CONCLUSION: Within this study, the device's discrimination performance for different caries depths was moderate to very good and it may be recommended as adjunct tool in the diagnosis of occlusal caries.

Caries detection and quantification around stained pits and fissures in occlusal tooth surfaces with fluorescence.

Occlusal discoloration due to staining frequently occurs on the pits and fissures of teeth. Noncariogenic discoloration (non-CD) refers to the attachment of staining chromogens to sound surfaces, whereas cariogenic discoloration (CD) represents the discoloration of porous structures due to bacterial metabolites and mineral loss from the enamel surface. This study evaluated whether it is possible to distinguish between non-CD and CD on stained occlusal surfaces with fluorescence assessed by the quantitative light-induced fluorescence (QLF) technology. Sixty-two extracted human permanent teeth with suspected discolorations on the pit and fissure were examined. The maximum values of fluorescence loss (ΔFmax) and red fluorescence gain (ΔRmax) were calculated using QLF images. Using histology as the gold standard, it was found that 12 teeth were sound (non-CD), while 50 teeth had enamel and dentine caries (CD). The validity tests at the enamel histological caries level, ΔRmax (ρ = 0.80) were strongly correlated with the histology (P < 0.001). At the optimum threshold (105.0) of ΔRmax, it showed high levels of sensitivity and specificity (0.96 and 0.83, respectively). Therefore, QLF can be used to distinguish non-CD from CD on occlusal surfaces using red fluorescence values with high validity.

Diagnosis of Pit-and-fissure Caries Using Three-dimensional Scanned Images.

Diagnosis of the extent of pit-and-fissure caries has been subjective and thus difficult to teach and categorize for treatment planning. This in vitro study compares occlusal caries diagnosis of extracted posterior teeth (n=49) using three-dimensional (3D) scanned images vs visual examination, according to the International Caries Detection and Assessment System (ICDAS). The surfaces chosen for study represent all ICDAS classifications. Five experienced restorative faculty members examined scanned images for 60 seconds from a standardized series of views of each surface and scored them independently. One month later, the same teeth were examined visually by the same five raters with magnification and LED headlamps, with compressed air available. Intrarater and interrater agreement and validity were assessed using intraclass correlation coefficients (ICCs). The ICCs, ranging from 0.90 to 0.93, indicated excellent agreement between and within raters and between the raters and the gold standard ICDAS determination. This suggests that both photographs and 3D scans of pits and fissures are equally effective in diagnosing caries.

Clinical analysis of molar fissures by Cone-beam tomography.

This study aimed to validate clinical analysis of 20 pediatric dentists on occlusal groove-fossa-system of molar depth comparing to Cone-beam tomography. The 48 sound third molars were visually classified from the shallowest to the deepest. Images were taken from the Accuitomo 3DX. There was a fair correlation between clinical analysis and the tomographic scorings (rs = 0.238; P = 0.103). It was concluded that pediatric dentists were not able to classify the fissures depth by visual analysis correctly.

Quantitative characterization and micro-CT mineral mapping of natural fissural enamel lesions.

OBJECTIVES: The aim of this study was to characterize the mineral distribution pattern of natural fissural enamel lesions and to quantify structural parameters and mineral density of these lesions in comparison to proximal white spot enamel lesions. METHODS: Imaging was undertaken using a high-resolution desktop micro-computed tomography system. A calibration equation was used to transform the grey level values of images into true mineral density values. The value of lesion parameters including the mineral density and the thickness of the surface layer of the enamel lesion were extracted from mineral density profiles. RESULTS: The thickness of the surface layer showed variation among different lesions and it ranged from 0-90 µm in proximal lesions and 0-137 µm in fissural lesions. The average thickness of surface layer in fissural lesions was significantly higher than smooth surface proximal lesions. Sound fissural enamel showed lower mineral density compared to proximal enamel. CONCLUSION: Micro-CT and the suggested de-noising and visualization method provide an efficient high-resolution approach for non-destructive evaluation of fissural lesions. Using these methods, the current study revealed the exclusive pattern and structure of fissural enamel lesions which may provide a basis for future studies on prevention and remineralization of these lesions. CLINICAL SIGNIFICANCE: The common demineralization pattern of fissural lesions, which indicates the extension of the lesion in two directions towards the pulp horns, may explain the early inflammation and symptoms of the pulp in fissural lesions even when the lesion base appears far from the pulp roof in normal radiographs. In addition, the presence of the surface layer, indicates that vigorous probing of the occlusal fissures may lead to breakage and cavitation of the enamel lesions.

A longitudinal study of occlusal caries among schoolchildren in Dar es Salaam, Tanzania.

OBJECTIVES: To describe the clinical caries status and the radiographic progression of occlusal caries lesions in permanent first and second molars among primary schoolchildren in Dar es Salaam over a 3-year period. METHODS: Clinical and radiographic diagnosis of caries in first and second permanent molars in 223 children aged 8-16 years were carried out annually from 1994 to 1997. The drop-out rates from the baseline in 1994 to the follow-up examinations in 1995, 1996 and 1997 were 16.6%, 22.0% and 35.4%, respectively. Twenty-one percent of the dropouts were picked up during the study. RESULTS: Less that 5% of all occlusal surfaces that were sound at the beginning of the study developed new clinical caries lesions over the 3-year study period. The highest rate of new lesions was found in second molars. The mandibular second molars were most frequently affected by new caries lesions followed by the mandibular first molars. Progression of lesions was generally slow. After 1, 2 and 3 years, 30.0%, 47.9% and 52.8% of lesions in occlusal surfaces of first molars had progressed, compared to 47.9%, 71.3% and 100.0% of lesions in second molars. CONCLUSIONS: Dental caries prevalence was low. New occlusal lesions were more likely to appear in mandibular second molars. Carious lesions were progressing slowly, especially in the first molars. Fissure abrasion may play a role in minimizing the risk of developing new occlusal lesions as well as progression of existing lesions.

A clinical evaluation of air-abrasion treatment of questionable carious lesions. A 12-month report.

BACKGROUND: The efficacy of treating questionable incipient lesions early with air abrasion, a modality used by many practitioners, has not been adequately demonstrated. METHODS: The authors enrolled 223 teeth, each with a questionable incipient pit-and-fissure carious lesion, from 93 dental patients in a projected five-year randomized clinical trial. Caries was defined as softness, decalcification or cavitation at the base of a pit or fissure or radiographic evidence of caries. Each tooth was randomly assigned to either a treatment group (n = 113 teeth) or a control group (n = 110 teeth) (which was observed but left untreated until the definition of caries was met). Each tooth in the treatment group was air-abraded and restored with a flowable resin-based composite. The authors re-examined teeth in both groups every six months; they evaluated the restorations using a modified set of Ryge criteria and inspected teeth for caries using radiographs, mirrors and standardized explorers. RESULTS: Of the 113 teeth with questionable incipient carious lesions air-abraded in the treatment group, 50 had caries extending into dentin. After 12 months of clinical service, there were three sealants that exhibited a partial loss of sealant which did not require any re-treatment. Two restorations with penetrating staining were re-treated. In the control group at the end of 12 months, only nine of the 86 recalled teeth were diagnosed with pit-and-fissure caries and were treated with air abrasion and restored with flowable resin-based composite. There was no statistically significant difference between the volume of the treatment and control preparations. CONCLUSION: After 12 months of clinical service, two preventive resin-based composite restorations in the treatment group required re-treatment. Fewer teeth than expected in the control group were diagnosed as having caries and were treated. CLINICAL IMPLICATIONS: The merit of treating questionable incipient pit-and-fissure carious lesions early with air abrasion has not been demonstrated after 12 months in this clinical study.

Hidden caries: what is it? Does it exist? Does it matter?

Hidden caries is a term used to describe occlusal dentine caries that is missed on a visual examination, but is large enough and demineralised enough to be detected radiographically. The detection rate of such lesions will depend upon the prevalence of caries in the population and the frequency with which bitewing radiographic examinations are performed. Whether 'hidden caries' is a distinct clinical entity, reflecting a particular anatomical fissure topography or a different bacterial aetiology, is unknown. It is possible that an improved visual examination, with careful cleaning and drying of teeth, may improve occlusal caries detection to the point where 'hidden caries' no longer exists. However, this possibility has yet to be tested clinically and until it is, practising dentists would be wise to examine bitewing radiographs carefully for occlusal demineralisation. The authors would treat such hidden lesions by removing soft caries and placing sealant restorations.

Visual-tactile examination compared with conventional radiography, digital radiography, and Diagnodent in the diagnosis of occlusal occult caries in extracted premolars.

PURPOSE: This laboratory study compared visual-tactile examination with conventional radiographs, digital radiographs, and laser fluorescence in the detection of occlusal occult caries on extracted premolar teeth. METHODS: Extracted premolars without obvious caries or restorations were collected from school dental clinics. Occlusal surfaces of 320 extracted premolars were examined visually with an explorer, then examined using the KaVo Diagnodent unit and scored using specific criteria. The teeth were exposed using conventional and digital radiography, respectively. The radiographs were assessed for dentin radiolucencies beneath the occlusal surface. RESULTS: Of the 320 teeth used in this study, 302 were scored as sound by visual-tactile examination. Of these, 57 (19%) demonstrated dentin radiolucency on conventional bite-wings, and 245 (81%) were scored as radiographically sound. Thus, the sensitivity and specificity values of the visual-tactile examination compared with conventional radiography were 81% and 44%, respectively. In contrast, Diagnodent produced results of 82% sensitivity and 36% specificity when compared with conventional radiography. When compared to digital radiography, the sensitivity and specificity values of the visual-tactile examination were 90% and 44%, respectively. In contrast, when compared to digital radiography, Diagnodent showed a very low specificity of only 32%, although sensitivity was still high at 91%. Differences in specificity among the techniques were statistically significant (P < .03), whereas differences in sensitivity were not (P > .01). CONCLUSIONS: Although the diagnosis of occult dentinal caries may be further enhanced by the Diagnodent, a combination of visual-tactile examination and either conventional or digital radiography should identify over 80% of lesions.

Is caries prevalence underestimated in today's caries examination? A study on 16-year-old children in the county of Bohuslän, Sweden.

When caries prevalence was higher than today incipient lesions constituted 70% of carious lesions. Incipient lesions were often neglected in caries recordings and hence the true caries prevalence was underestimated. Moreover, it has been shown that there were evident differences in caries status between different areas in the same county though the preventive measures were supposed to be the same (Moberg Sköld et al 1984). To find out if the conditions were the same when caries prevalence has decreased a total number of 240 16-year-old children were examined concerning caries in 1987 and 1990. The results showed that the caries prevalence was still underestimated. Incipient lesions constituted 80% of the total number of carious lesions which was approximately the same as when caries prevalence was higher. The difference in caries status within the country had decreased compared with the study in 1984 (Moberg Sköld et al 1984).

Fissure caries diagnosis and resulting treatment decisions by clinical community dental officers and general dental practitioners.

In this in vitro study, 12 General Dental Practitioners and 13 Clinical Community Dental Officers examined the occlusal, buccal and palatal pits and fissures of 35 extracted molar teeth. They were asked to make a management/treatment decision, on the basis of their diagnosis of caries, whether each tooth should be left untreated, fissure sealed or investigated. After all the management/treatment decisions had been made, the teeth were serially sectioned perpendicular to the occlusal surface and examined for the presence of caries in dentine. It was impossible to demonstrate differences in the management/treatment decisions and the diagnosis of caries made by the two groups. No significant difference in sensitivity or specificity could be detected between operators diagnosing by visual inspection alone and those using visual inspection in combination with a tactile method. The use of radiographs did not significantly improve the validity of the diagnosis or management of fissure caries.

[The caries incidence in schoolchildren in the Canton of Glarus 13 years after the introduction of highly fluoridated salt]. / Kariesbefall bei Schulkindern des Kantons Glarus, 13 Jahre nach der Einführung des höher fluoridierten Salzes.

Addition of 250 ppm fluoride to domestic salt and salt used by bakeries was begun in 1974-1976 in the Canton of Glarus. The caries examinations revealed a rapid decline of DMFT averages in the four age groups (8, 10, 12, 14 years) by 71 to 78 percent from 1974 to 1987. DMF counts in fissures and pits also decreased by 61 to 80%. In the primary dentition, the number of sound teeth and of sound approximal molar surfaces increased. The average fluoride levels in urinary spot specimens were 0.36 ppm in 1974 and varied between 0.74 and 0.80 ppm from 1979 to 1987. In autumn 1982 toothbrushing exercises with fluoride preparations were introduced. They should have been carried out two to six times a year but were discontinued in 1983 and 1984 in part of the communities. This educational program therefore had little effect on the total reduction, the main decline having occurred from 1974 to 1983. The reduction from 1974 to 1987 was too high and too rapid to be exclusively due to the fluoride in salt but other factors changed little. The percentage of fluoride dentifrice rose only slightly and Swiss averages of sugar and sweet consumption remained almost stable from 1976 to 1987.

Will modern caries management reduce restorations in dental practice?

Dentists have difficulty diagnosing caries presence and activity. Modern caries management suggests that lesions in low risk patients should not be restored until the radiolucency extends into the outer third of interproximal dentin. Even stained fissures need not be restored in the absence of occlusal dentin radiolucency. If this standard were adopted, what affect would it have on the amount of operative treatment delivered? This report created a model to forecast the change in work volume caused by new caries management strategies. The model considered two identical groups of 1,000 adult teeth with a normal distribution of 1,000 radiographic lesions in each group. Group I would have all lesions restored at baseline, but Group II would have only lesions in the dentin restored. Each year for ten years the model forecasts the number of replacement restorations for both groups, plus initial restorations for Group II. A sensitivity analysis was conducted using slow progression rates (Group IIa) and fast progression rates (Group IIb). After ten years, Group IIa has 49% and Group IIb had 32% fewer restorations than Group I. It is concluded that the model is robust and modern caries management may significantly reduce operative workload.

Irregularities below the enamel-dentin junction may predispose for fissure caries.

This study investigated the structure of the fissure fundus on occlusal surfaces with respect to the detection of possible irregularities below the enamel-dentin junction (EDJ). Occlusal surfaces were examined by micro-computed tomography (µCT). In total, 203 third molars with clinically sound occlusal fissures or non-cavitated lesions were selected. All specimens were scanned with µCT. Subsequently, each tooth was sectioned, and each slice was investigated by stereomicroscopy. In 7 of 203 molars (3.4%), demarcated radiolucencies below the EDJ were detected by µCT. These defects were obviously of non-carious origin, because the µCT images revealed no gradient of demineralization in the dentin. In all cases, a direct pathway between the oral cavity and the dentin was evident. The comparison of the µCT sites with conventional histological images also revealed defects in the dentin. These results demonstrate that demarcated radiolucencies below the EDJ may not necessarily be caries lesions according to µCT images and may be classified as possible developmental irregularities. To avoid misinterpreting µCT data, dental researchers should carefully consider this condition when analyzing µCT images. The clinical significance of this finding is that these defects may predispose molar teeth to early-onset caries in occlusal pits and fissures.