Xie-Qi Shi

Occlusal Caries Detection with KaVo DIAGNOdent and Radiography: An in vitro Comparison

A new laser fluorescence method, KaVo DIAGNOdent, was tested with respect to reproducibility and validity and compared with radiography regarding accuracy in the detection of occlusal caries. Seventy–six extracted premolar and molar teeth were measured twice with DIAGNOdent under both wet and dry conditions, at an interval of 2 weeks. Conventional film radiographs were exposed. Microradiographic analysis of sections of the teeth served as the gold standard. Intra–class correlation coefficient and Pearson’s correlation coefficient were used to assess the reproducibility and the validity of the method, respectively. The influence of time and varying humidities on DIAGNOdent readings were analysed by two–way repeated measure ANOVA. ROC curves were plotted for DIAGNOdent readings and radiographic registration of caries by 6 observers, and the areas under the curves were compared using Student’s t test. Under both wet and dry conditions, the reproducibility of the DIAGNOdent method was excellent: R = 0.97 and 0.96, respectively. The diagnostic accuracy of DIAGNOdent was significantly better than that of radiography (p≤0.001). In this in vitro study of detection of occlusal caries, the diagnostic performance of the DIAGNOdent method was superior to that of radiography.

Validation of DIAGNOdent for quantification of smooth-surface caries: an in vitro study

The aims were 1) to validate a laser-based device, KaVo DIAGNOdent, for quantification of caries lesions on smooth surfaces, using histopathologic and microradiographic analyses as the gold standard, and 2) to test inter- and intra-observer agreements. We also investigated the influence on DIAGNOdent readings of the storage medium used for extracted teeth. Two observers measured independently the tooth surfaces of 40 extracted premolars that had been stored in thymol-saturated saline. After subsequent storage in neutral-buffered formalin for 14 days they were re-measured. The teeth were then sectioned for histopathologic and microradiographic analysis. The Spearman rank correlation coefficients between lesion depth and DIAGNOdent readings were 0.78–0.83 and 0.85 for teeth stored in thymol-saturated saline and formalin, respectively. Inter- and intra-observer agreements were 0.94 and 0.95 when the teeth were stored in thymol-saturated saline. The DIAGNOdent reading was almost 1.5 times higher for teeth stored in formalin than for those stored in thymol saline. The Spearman rank correlation coefficient between mineral loss in enamel (ΔZ) and DIAGNOdent readings ranged from 0.64 to 0.68. It was concluded that DIAGNOdent may be helpful for assessing smooth-surface caries, but the cut-off points need to be assessed under clinical conditions. The increase in fluorescence associated with storage of teeth in formalin warrants further investigation.

In vivo Repeatability and Reproducibility of the Quantitative Light-Induced Fluorescence Method

In vivo repeatability and reproducibility of the quantitative light-induced fluorescence (QLF) method were tested with respect to three variables: lesion area, and average and maximum changes in lesion fluorescence. To test the image-capturing stages, three analysts each captured images of 15 incipient smooth surface lesions in vivo, and the images were analysed by one of the analysts. To test the analytical stage of the method, three analysts analysed the images of 15 in vivo incipient smooth surface lesions. For the image-capturing stage, inter-examiner reliability showed an intra-class correlation coefficient (r) between 0.95 and 0.98. For the analytical stage, intra-examiner reliability for all three analysts showed a value of r between 0.93 and 0.99. Inter-examiner reliability showed a value of r between 0.95 and 0.99. It was concluded that the in vivo repeatability and reproducibility of the QLF method are excellent.

Occlusal caries detection and quantification by DIAGNOdent and Electronic Caries Monitor: in vitro comparison

The Electronic Caries Monitor (ECM) and the recently introduced laser-based KaVo DIAGNOdent have been developed as clinical diagnostic aids in the detection and quantification of occlusal carious lesions. The aim of this in vitro study was to compare their reproducibility and validity. The ability of DIAGNOdent to retrieve sites of occlusal carious lesions without reference to photographs or drawings from previous assessments was also tested. The material comprised 87 premolar teeth: the occlusal surfaces were sound or exhibited non-cavity carious lesions of varying severity. All were photographed and measured by DIAGNOdent and ECM on 2 occasions, 2 weeks apart. The teeth were then sectioned into 300 µm thick slices. Two observers independently classified the sections according to the histopathology, into 5 categories, ranging from sound to dentinal caries in the inner part of the dentin. Statistical analysis comprised intra-class correlation coefficients (ICC) to test reproducibility and regression analysis of validity. Sensitivity and specificity were also calculated for detection of D3 lesions for both devices. DIAGNOdent recorded maximum readings at identical sites on both occasions in 89% of the teeth. The ICC for readings on 2 separate occasions was 0.97 for DIAGNOdent and 0.71 for ECM. The correlations with histology were r = 0.93 and 0.83, for DIAGNOdent and ECM, respectively. For detection of D3 lesions, the sensitivity and specificity were 0.8 and 1 for DIAGNOdent and 0.75 and 0.88 for ECM. In this in vitro study, DIAGNOdent was superior to ECM for occlusal caries detection.

In vitro quantification of white spot enamel lesions adjacent to fixed orthodontic appliances using quantitative light‐induced fluorescence and DIAGNOdent

The aims of this in vitro study were 2‐fold: 1) to evaluate two fluorescence methods (DIAGNOdent and QLF (quantitative light‐induced fluorescence)) for quantification of white spot lesions adjacent to fixed orthodontic appliances; and 2) to determine the inter‐observer agreement of the DIAGNOdent and QLF methods for quantification of incipient enamel lesions adjacent to fixed orthodontic appliances. Forty‐one premolar teeth with visually sound smooth surfaces or visually white spot enamel lesions were included in the study. Orthodontic brackets were fixed adjacent to the lesions, thus simulating the position of fixed appliances during orthodontic treatment. All teeth were measured using both the DIAGNOdent and QLF methods. Of the 41 teeth, 20 smooth surfaces were randomly selected and analyzed by 4 operators using both DIAGNOdent and QLF. The teeth were sectioned into 300‐μm‐thick slices using a water‐cooled diamond saw and the slices manually ground to 80–100 μm thickness. Histopathology and transverse microradiography were performed to provide the gold standards for verification of lesion depth and mineral loss, respectively. The Spearman rank correlation coefficients between lesion depth determined by histopathology and the DIAGNOdent and QLF were 0.76 and 0.82, respectively, whereas the Pearson correlation coefficients between mineral loss and the two methods were 0.64 and 0.84, respectively. Inter‐observer agreement was found to be 0.80 and 0.93 for DIAGNOdent and QLF, respectively. In conclusion, QLF may be a suitable method for quantifying incipient carious lesions adjacent to fixed orthodontic appliances.

Secondary caries detection by DIAGNOdent and radiography: a comparative in vitro study

DIAGNOdent is now well documented for detection of primary occlusal caries, but not as yet for secondary caries. The aim of this study was to investigate the application of DIAGNOdent for in vitro detection of secondary caries. The material comprised 66 extracted teeth: 48 with amalgam restorations and 18 with tooth‐colored restorations. Digital images of occlusal surfaces were captured for each specimen. The teeth were mounted in groups of 3 or 4 in plaster blocks simulating their anatomical positions. Bitewing radiographs of each block were assessed for secondary caries by 5 observers. The margins of each restoration were carefully scanned with DIAGNOdent; the site of the highest reading was localized in digital images; and the corresponding values were registered. Marginal integrity and staining were also documented. The restorations were then removed and the teeth were hemi‐sectioned. For verification, two observers working together examined all the cavities under a stereomicroscope at 16 x magnification followed by probing. Sensitivity and specificity for DIAGNOdent and conventional radiography were 0.77/0.81 and 0.65/0.81, respectively. Regarding ROC analyses, the A z values were 0.89 and 0.72 for DIAGNOdent and radiography. For DIAGNOdent, the false‐positive fraction included only stained teeth. Cohens kappa statistics disclosed moderate agreement between the 2 methods, with an agreement of 56%. DIAGNOdent tended to give more positive diagnoses than bitewing radiography. The results indicate that DIAGNOdent may be a helpful tool for detecting secondary caries.

In vitro quantification of smooth surface caries with DIAGNOdent and the DIAGNOdent pen.

Objective. A new generation of the laser fluorescence device, DIAGNOdent, for caries detection and quantification has been introduced recently. It is the DIAGNOdent pen. The aim of this study was to compare the validity and reliability of both laser-based devices, DIAGNOdent and the DIAGNOdent pen, in quantifying smooth surface caries. Material and Methods. The material comprised a sample of 52 premolar teeth extracted on orthodontic indication. The teeth were visually sound or had various stages of non-cavitated carious lesions on smooth surfaces. All teeth were photographed and measured with both DIAGNOdent and the DIAGNOdent pen by two examiners independently. The teeth were then sectioned into 300-µm slices and analysed under a microscope for verification of lesion depth. Histopathological analyses were performed by two observers to assess lesion depth, which was classified into five categories ranging from sound to dentinal caries. Reliability and validity of the two devices were evaluated in terms of intra-class coefficients and Spearman rank correlation coefficient, respectively. The relation between measurements performed by DIAGNOdent and the DIAGNOdent pen was analyzed using Pearsons correlation coefficient. Results. Both DIAGNOdent and the DIAGNOdent pen had excellent intra-observer agreement and acceptable inter-observer agreement. The correlation with histology for DIAGNOdent and the DIAGNOdent pen ranged between 0.47 and 0.57, although the correlation between DIAGNOdent and the DIAGNOdent pen was high. Conclusions. In this in vitro study, the new laser fluorescence device, the DIAGNOdent pen, showed similar reliability and validity at quantification of smooth surface caries compared to the conventional DIAGNOdent device. Agreement between DIAGNOdent and the DIAGNOdent pen was excellent.

Comparative analysis of upper airway volume with lateral cephalograms and cone-beam computed tomography.

INTRODUCTION In this study, we aimed to evaluate the adenoidal nasopharyngeal ratio (ANR) on lateral cephalograms by assessing upper airway volumes using cone-beam computed tomography (CBCT) images as the validation method. METHODS Fifty-five patients were included in the study, and it was essential that the lateral cephalograms and CBCT images taken at their examinations were not more than 1 week apart. There were 32 subjects in group A (age ≤15 years) and 23 subjects in group B (age >15 years). The ANR was measured on the lateral cephalograms. The area and volumetric measurements of the nasopharynx and the total upper airway were obtained from CBCT images. Repeated measurements of the ANR and airway volume were performed on 10 subjects by 2 observers. RESULTS Group A had a higher correlation (r = -0.78) between the ANR and the nasopharynx volume than did group B (r = -0.57). The ANR had a weak correlation with the total upper airway volume (group A, r = -0.48; group B, r = -0.32). Both measurements made on lateral cephalograms and CBCT were highly reproducible in terms of intraobserver and interobserver agreement. CONCLUSIONS Based on our results, the measurement of the ANR on lateral cephalograms can be used as an initial screening method to estimate the nasopharynx volumes of younger patients (age ≤15 years).

Exposure parameters in sens-a-ray direct digital radiography and their effects on diagnostic accuracy of carious lesions

We studied the effects of tube potentials and exposures on the accuracy of carious diagnosis using Sens-A-Ray direct digital radiography with two types of CCD detectors, one without and one with a scintillator layer. Our second objective was to determine the optimum exposure factors.Radiographs of 75 extracted premolars with and without clinically observed discolorations or cavities were obtained at exposure settings of 70 kVp and 90 kVp. The observers diagnosed dental caries in radiographs exposed with the two types of detectors. The results were analyzed with Receiver Operating Curve (ROC) technique. The averaged areas under the ROC curves were plotted as functions of exposure to obtain Diagnostic Accuracy (DA) curves.No statistically significant difference was found in diagnostic accuracy for the two tube potentials. However, there was a statistically significant difference in diagnostic accuracy for the two lesion types, discolorations and cavities. There was also a significant effect on diagnostic accuracy related to exposure: the exposure providing the optimum diagnostic accuracy corresponds to a gray level of about 31 when SVGA graphics are employed, i.e., in the middle of the available range.To acquire optimum radiographs for diagnosing carious lesions with the Sens-A-Ray system, the operator must select the appropriate exposure parameters.

A color coding method for radiographic images

Abstract A color scale was designed with an approach that combined both human visual response to color and physical properties of color. The design was initiated with a subjective evaluation of a 16 step color scale running from dark blue via magenta, orange to light yellow. The CIELUV chromaticity diagram was employed to verify the subjectively generated scale and to ensure that the differences in hue between the 16 steps was as equal as possible. The brightness of each step was adjusted to fit the function of the so-called L ∗ , which represents the response of the human visual system to luminance. Preliminary results using a computer generated radiograph indicate improved perception in color-coded than in black-and-white radiographs.