Predicting occlusal caries using the Electronic Caries Monitor

Electrical conductance for the detection of dental caries

BACKGROUND

Caries is one of the most prevalent, preventable conditions worldwide. A wide variety of management options are available at different thresholds of disease, ranging from non-operative preventive strategies such as improved oral hygiene, reduced sugar diet, and application of topical fluoride, to minimally invasive treatments for early lesions which are limited to enamel, through to selective removal and restoration for extensive lesions. The cornerstone of caries detection is a visual and tactile dental examination, however, an increasing array of methods of caries lesion detection have been proposed that could potentially support traditional methods of detection and diagnosis. Earlier identification of disease could afford patients the opportunity of less invasive treatment with less destruction of tooth tissue, reduce the need for treatment with aerosol-generating procedures, and potentially result in a reduced cost of care to the patient and to healthcare services.

OBJECTIVES

Our primary objective was to determine the diagnostic accuracy of different electrical conductance devices for the detection and diagnosis of non-cavitated coronal dental caries in different populations (children, adolescents, and adults) and when tested against different reference standards.

SEARCH METHODS

Cochrane Oral Health's Information Specialist undertook a search of the following databases: MEDLINE Ovid (1946 to 26 April 2019); Embase Ovid (1980 to 26 April 2019); US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov, to 26 April 2019); and the World Health Organization International Clinical Trials Registry Platform (to 26 April 2019). We studied reference lists as well as published systematic review articles.

SELECTION CRITERIA

We included diagnostic accuracy studies that compared electrical conductance devices with a reference standard of histology or an enhanced visual examination. This included prospective studies that evaluated the diagnostic accuracy of single index tests and studies that directly compared two or more index tests. We included studies using previously extracted teeth or those that recruited participants with teeth believed to be sound or with early lesions limited to enamel. Studies that explicitly recruited participants with more advanced lesions that were obviously into dentine or frankly cavitated were excluded.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data independently using a piloted study data extraction form based on the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2). Sensitivity and specificity with 95% confidence intervals (CIs) were reported for each study. This information was displayed as coupled forest plots, and plotted as summary receiver operating characteristic (SROC) plots, displaying the sensitivity-specificity points for each study. Due to variability in thresholds we estimated diagnostic accuracy using hierarchical summary receiver operating characteristic (HSROC) methods.

MAIN RESULTS

We included seven studies reporting a total of 719 tooth sites or surfaces, with an overall prevalence of the target condition of 73% (528 tooth sites or surfaces). The included studies evaluated two index tests: the electronic caries monitor (ECM) (four studies, 475 tooth surfaces) and CarieScan Pro (three studies, 244 tooth surfaces). Six studies used histology as the reference standard, one used an enhanced visual examination. No study was considered to be at low risk of bias across all four domains or low concern for applicability or both. All studies were at high (five studies) or unclear (two studies) risk of bias for the patient selection domain. We judged two studies to be at unclear risk of bias for the index test domain, and one study to be at high risk of bias for the reference standard and flow and timing domains. We judged three studies to be at low concern for applicability for patient selection, and all seven studies to be of low concern for reference standard and flow and timing domains. Studies were synthesised using a hierarchical method for meta-analysis. There was variability in the results of the individual studies, with sensitivities which ranged from 0.55 to 0.98 and specificities from 0 to 1.00. These extreme values of specificity may be explained by a low number of healthy tooth surfaces in the included samples. The diagnostic odds ratio (DOR) was 15.65 (95% CI 1.43 to 171.15), and indicative of the variability in the included studies. Through meta-regression we observed no meaningful difference in accuracy according to device type or dentition. Due to the small number of studies we were unable to formally investigate other potential sources of heterogeneity. We judged the certainty of the evidence as very low, and downgraded for risk of bias due to limitations in the design and conduct of the included studies, imprecision arising from the relatively small number of surfaces studied, and inconsistency due to the variability of results.

AUTHORS' CONCLUSIONS

The design and conduct of studies to determine the diagnostic accuracy of methods to detect and diagnose caries in situ is particularly challenging. The evidence base to support the detection and diagnosis of caries with electrical conductance devices is sparse. Newer electrical conductance devices show promise and further research at the enamel caries threshold using a robust study design to minimise bias is warranted. In terms of applicability, any future studies should be carried out in a clinical setting to provide a realistic assessment within the oral cavity where plaque, staining, and restorations can be problematic.

Electrical Measurements for Use in Caries Clinical Trials

This paper reviews the use of electrical measurements of caries, particularly in relation to caries clinical trials. Electrical measurements change as tooth tissue porosity alters in the caries process, but several other variables also have a significant effect on these electrical measurements and hence upon their diagnostic validity. Available electrical-method data, in the context of clinical trials, relate to the use of the Electronic Caries Monitor (ECM), which measures “bulk” resistance. The device is presently limited in scope to occlusal surfaces, and only limited ECM data from clinical trials are available. In the context of clinical trials, more work is needed to determine the potential role of electrical measurements. Such research will need to focus both on an understanding of those electrical parameters which are most valuable in identifying changes and stages in the caries process in individual teeth and also on identifying the extent of the effects of the variables affecting these measurements.

In vivo study of different methods for diagnosing pit and fissure caries

Background

In recent years the early detection of such caries has gained importance, since it may avoid unnecessary dental tissue damage and allow minimally invasive dental treatment. A study is made of 5 systems for diagnosing caries: traditional visual and tactile methods, DIAGNOdent, VistaProof and CarieScan.

Material and Methods

A prospective study was made in the Department of Stomatology, Dental Pathology and Therapeutics Teaching unit of the University of Valencia (Valencia, Spain), involving the analysis of 32 teeth (molars or premolars of both arches scheduled for filling or for use as posts in dental bridges) in 28 patients. The following caries diagnostic methods were applied: visual, tactile, DIAGNOdent (KAvo, Biberach, Germany), VistaProof (Dürr Dental AG, Bietigheim-Bissingen, Germany) and CarieScan (IDMoS Dental Systems, Dundee, Scotland, United Kingdom). Fissurotomy was subsequently performed for histological validation.

Results

Visual inspection showed an area under the receiver operating characteristic curve (AUC-ROC) of 0.75, with a sensitivity and specificity of 0.75. Tactile diagnosis in turn showed AUC = 0.714, with maximum sensitivity (100%) and a specificity of 42.9%. DIAGNOdent (cutoff point 22.5) and VistaProof (cutoff point 1.1) showed AUC = 0.969, while CarieScan (cutoff point 21.5) presented AUC = 0.973. These latter three methods all had a sensitivity of over 92%. The specificity of DIAGNOdent was maximum, while that of CarieScan and VistaProof was 75%.

Conclusions

The emergent methods in the diagnosis of caries (DIAGNOdent, VistaProof and CarieScan) yielded similar results, and in all cases proved superior to the traditional visual and tactile methods. DIAGNOdent was seen to be the most effective technique, followed by CarieScan and VistaProof.

Key words:Caries diagnosis, emergent diagnostic methods, fluorescence, electrical impedance, minimally invasive dentistry.

An in vitro comparison of different diagnostic methods in detection of residual dentinal caries

The aim of this study was to investigate the efficiency of different diagnostic methods in detection of residual dentinal caries in excavated cavities. Fifty extracted molar with deep dentinal carious lesions were excavated using a slow-speed handpiece. All cavities were assessed by laser fluorescence(LF) device, electronic caries monitor(ECM), and caries detector dye(CDD) by three independent observers blindly. The measurements were repeated after two weeks. Specimens containing dentin slices 150 μm in thickness were prepared for histological analyses. The existence and absence of carious dentin was determined using a lightmicroscope. The average intraobserver accuracy was 1.00 (perfect agreement) for CDD, 0.86 (excellent agreement) for ECM, and 0.50 (good agreement) for LF. The average interobserver accuracy values were 0.92 (excellent agreement), (0.36 marginal agreement) and 0.48 (good agreement), for CDD, ECM, and LF, respectively. The average specificity was 0.60 for CDD, 73% for ECM, and 0.50 for LF. The average sensitivity was 0.55 for CDD, 0.85 for LF, and 0.47 for ECM. The average accuracy values were 0.53, 0.51, and 0.81 for CDD, ECM, and LF, respectively. LF had the greatest sensitivity and accuracy values of any of the methods tested. As a conclusion, LF device is appeared to most reliable method in detection of remain caries in cavity. However, because of its technical sensitivity it may susceptible to variations in measurements. To pay attention to the rule of usage and repeated measurements can minimize such variations in clinical practice. It was concluded that LF is an improvement on the currently available aids for residual caries detection.

Comparison of paired visual assessment and software analyses of changes in caries status over 6 months from fluorescence images

Images captured using light-induced fluorescence systems are generally analysed using proprietary software. The purpose of this study was to determine if such images could be scored visually and to compare these data with those metrics produced by the software. A total of 171 lesions were selected from a pool of images to provide a range of lesions which were reported as having remained static, increased or decreased in fluorescence using the QLF analysis software. The baseline and 6-month images were then assessed side by side on a computer screen by 10 examiners who were asked to rate the lesions to determine if the lesion had become better or worse, or had stayed the same. There was generally poor correlation between clinical visual image assessments and all QLF analysis outcomes for all examiners. The agreement amongst the visual image assessments for the 10 examiners compared to the average score ranged from kappa 0.22 to 0.59 and the rank correlations from -0.01 to 0.73. This study suggests that the visual assessment of lesion images by the examiners in this study was based upon different characteristics of lesion change than those utilised by the QLF analysis software. A clearer understanding of lesion characteristics that are indicative of positive and negative changes may be required before this technology can be exploited to its full potential.

Water content and apparent stiffness of non-caries versus caries-affected human dentin

Caries-affected dentin contains less mineral and more water than surrounding normal dentin. Such dentin should be less stiff and should shrink more than normal dentin when dried. The purpose of this study was to test the relationships between the stiffness, shrinkage, and water content of caries-affected versus normal dentin. Extracted human carious third molars were stained with caries-detector dye and the occlusal surfaces ground down until only caries-affected dentin remained, surrounded by normal dentin. Dentin disks were prepared from these crowns placed in a aluminum well positioned under a modified thermal mechanical analyzer. Changes in specimen height and stiffness were measured following drying or static loading in both caries-affected and surrounding normal dentin. Core samples of these two types of dentin were used to gravimetrically measure water content. Two-way ANOVA and regression analysis was used to test the relationship between shrinkage versus water content, stiffness versus water content, and stiffness versus shrinkage. Caries-affected dentin was found to be less stiff and contained more water than normal dentin (p < 0.05). Regression analysis revealed highly significant inverse relationships between stiffness and water content, and stiffness and shrinkage (p < 0.0005).

In vitro Assessment of Methods of Applying the Electrical Caries Monitor for the Detection of Occlusal Caries

The aim of this in vitro study was to assess the diagnostic performance of five methods of using the Electrical Caries Monitor (ECM) to detect caries lesions at enamel and dentine thresholds in occlusal molar surfaces with and without stain. Histological validation was performed in 152 occlusal sites in permanent molar teeth. For the sites without stain the areas under the ROC curve (AUC) for the five methods ranged from 0.69 to 0.93 (enamel) and 0.74 to 0.92 (dentine). For stained sites the AUC ranged from 0.59 to 0.65 (enamel) and 0.66 to 0.77 (dentine). The performance of the ECM was reduced in the presence of stain. The measurements using toothpaste as a conducting medium were generally worse than when direct measurements were taken. The profiles of the resistance curves generated as the tooth was dried for 5 s were used to derive additional summary variables. The AUC for all sites using an outcome variable generated from these data were 0.89 (enamel) and 0.91 (dentine), respectively, for all teeth. It is concluded that the performance of the ECM might be improved by either considering a combination of variables or using different resistance cut-offs in the presence or absence of stain.

The assessment of an intra-oral video camera as an aid to occlusal caries detection

AIMS

To investigate the use of intra-oral video cameras (IOVCs) for occlusal caries detection.

DESIGN

Eighty premolars and molars set-up to simulate clinical conditions were examined by six examiners using three techniques: visual examination (EX), an IOVC (CAM) and by watching a video that was recorded using an intra-oral video camera (VID). The teeth were then sectioned for histological validation.

RESULTS

30 surfaces had lesions limited to enamel and 39 had lesions extending into dentine. Sensitivity scores at the D1 threshold (enamel and dentine lesions) were 43% (EX), 68% (CAM) and 77% (VID) whilst the specificity scores were 92% (EX), 64% (CAM) and 60% (VID). Corresponding results at the D3 threshold (caries extending into dentine) were 27%, 42%, 60%, 97%, 99% and 77%.

CONCLUSIONS

Compared to unaided vision, the use of an IOVC significantly increases the number of occlusal lesions detected, however, there is a rise in false positive scores at the D1 threshold. The use of the video technique also significantly increases the number of occlusal lesions detected but with a concurrent rise in false positive scores at both thresholds.

An in vitro comparison of a combined FOTI/visual examination of occlusal caries with other caries diagnostic methods and the effect of stain on their diagnostic performance

The aims of this in vitro study were to compare the combination of FOTI and visual inspection to other diagnostic methods for the detection and evaluation of the depth of occlusal caries and assess the effect of stain on diagnostic performance. Five diagnostic methods (combined FOTI/Visual (CFV), Visual, FOTI, DIAGNOdent and Electrical Caries Monitor) were considered. Histological validation was performed in the 152 occlusal molar sites (111 teeth) using 350-microm sections and a stereomicroscope. The rank correlation coefficients with histology ranged from 0.42 (DIAGNOdent) to 0.66 (CFV). The area under the ROC curves (AUC) for enamel lesions ranged from 0.82 (ECM) to 0.88 (CFV) and from 0.81 (DIAGNOdent) to 0.91 (CFV) for dentine lesions. The AUC at the dentine level for CFV and FOTI were similar (p > 0.05), but the AUC for CFV was significantly greater than for visual (p < 0.001), DIAGNOdent (p = 0.005) and the ECM (p = 0.04). FOTI was found to be particularly useful for the detection of dentine lesions. The exclusion of stain and brown spot lesions improved performance for all methods. It is concluded that CFV is useful for the determination of occlusal lesion depth and that in the presence of stain and brown spot lesions different cut-off points may be required for the ECM and DIAGNOdent to identify dentine lesions.