B. Güniz Baksı

Differences in aluminum equivalent values of endodontic sealers: conventional versus digital radiography.

The aims of this study were to compare film and digital radiography in assessing the radiopacities of root canal sealers and to establish the relation in aluminum equivalent values of different methods. Standard disks of 5 different sealers were exposed together with an aluminum step wedge by using occlusal films and storage phosphor plates. Optical density of the sealers was evaluated by transmission densitometry, and mean gray values were determined by digital analysis. The data were analyzed by using two-way analysis of variance (P = .05). Pairwise comparisons were made by using Tukey post hoc and paired t tests (P = .05). The order from the most radiopaque to the most radiolucent sealer was the same for both methods; however, aluminum equivalent values determined by transmission densitometry were significantly higher (P < .01). Aluminum equivalent values of the 2 radiographic methods were 7%-20% different. The International Standards Organization standard for the radiopacity of dental root canal sealing materials needs modifications for digital systems.

Idiopathic root resorption of the entire permanent dentition: systematic review and report of a case

A rare case of idiopathic root resorption affecting the entire dentition was described. Root resorptions of all of the maxillary and mandibular teeth were coincidentally diagnosed on patients radiographic examination. The patients medical and dental findings were non-contributory, other than the increased mobility of upper incisors. No significant familial findings could be identified. Detailed radiographic examination revealed resorption affecting the apical part of the roots, resulting in vertical shortening of the teeth. The character of the resorption was as if a tapering occurred throughout the lateral root surfaces. Involved teeth were endodontically treated and the patient was subsequently followed-up for 18 months. Following endodontic therapy, all periapical lesions demonstrated clinical and radiographic evidence of healing. Endodontic therapy resulted in a high degree of success to stop resorption process and maintain the dentition.

Measurement accuracy and perceived quality of imaging systems for the evaluation of periodontal structures.

The aim of this study was to compare the subjective diagnostic quality of F-speed film images and original and enhanced storage phosphor plate (SPP) digital images for the visualization of periodontal ligament space (PLS) and periapical (PB) and alveolar crestal bone (CB) and to assess the accuracy of these image modalities for the measurement of alveolar bone levels. Standardized images of six dried mandibles were obtained with film and Digora SPPs. Six evaluators rated the visibility of anatomical structures using a three-point scale. Alveolar bone levels were measured from the coronal-most tip of the marginal bone to a reference point. Results were compared by using Friedman and Wilcoxon signed-ranks tests. The kappa (κ) statistic was used to measure agreement among observers. The measurements were compared using repeated measures analysis of variance and Bonferroni tests (P = 0.05). A paired t test was used for comparison with true bone levels (P = 0.05). Enhanced SPP images were rated superior, followed by film and then the original SPP images, for the evaluation of anatomical structures. The value of κ rose from fair to substantial after the enhancement of the SPP images. Film and enhanced SPP images provided alveolar bone lengths close to the true bone lengths. Enhancement of digital images provided better visibility and resulted in comparable accuracy to film images for the evaluation of periodontal structures.

Effect of tube potential and image receptor on the detection of natural proximal caries in primary teeth

The aim of this study was to assess the detection of proximal caries in primary teeth at three different tube potentials using Ektaspeed films, storage phosphor plates (SPPs), and a charge-coupled device (CCD). Fifty-three extracted human primary molars with natural proximal caries were radiographed with three different imaging modalities—Digora Optime SPP system, RVGui CCD system, and Ektaspeed films—at 50-, 65-, and 70-kV tube potentials. Three observers scored the resultant images for the presence or absence of caries. The definitive diagnosis was determined by stereomicroscopic assessment. The diagnostic accuracy for each imaging modality was expressed as the area under the receiver operating characteristic curves (Az). Differences among the Az values were assessed using two-way ANOVA and t tests. Kappa was used to measure inter- and intra-observer agreement. Higher accuracy was found for SPPs compared to film and CCD images at all tube potentials. Accuracy was significantly different only at 50-kV tube setting in favor of SPPs (p < 0.05). Inter- and intra-observer agreement was high for all systems. A SPP system can be recommended for dental peadodontic clinics particularly with 50-kV tube potential for the diagnosis of proximal caries since further advantages include the elimination of chemical processing, image enhancement, and a better low-contrast detectability performance.

LCD and CRT display of storage phosphor plate and limited cone beam computed tomography images for the evaluation of root canal fillings.

The aim was to compare quality of liquid crystal display (LCD) and high resolution cathode ray tube (CRT) screens for the evaluation of length and homogeneity of root canal fillings in storage phosphor plate (SPP) and limited cone beam computed tomography (LCBCT) images. Endodontic treatment was performed to 17 extracted permanent lower incisor teeth. Images of each tooth positioned in a dried mandible were obtained with Digora® SPP and Accu-I-Tomo LCBCT systems. Six observers scored the quality of all images on CRT and LCD screens. Results were compared using McNemar’s and Cochran’s Q tests (p < 0.05). The differences among the LCBCT and SPP images were determined by binomial test. No significant difference was found between ratings of CRT and LCD displays (p > 0.05). Agreement among observers’ scores was higher with CRT display. Within the limits of this ex vivo study, differences between LCD and CRT monitors for the evaluation of root canal fillings are clinically insignificant independent on whether conventional radiographs, captured by means of image plates, or cone beam images are being displayed.

Fractal Analysis of Periapical Bone from Lossy Compressed Radiographs: A Comparison of Two Lossy Compression Methods

The aim of the study was to evaluate the effect of two lossy image compression methods on fractal dimension (FD) calculation. Ten periapical images of the posterior teeth with no restorations or previous root canal therapy were obtained using storage phosphor plates and were saved in TIF format. Then, all images were compressed with lossy JPEG and JPEG2000 compression methods at five compression levels, i.e., 90, 70, 50, 30, and 10. Compressed file sizes from all images and compression ratios were calculated. On each image, two regions of interest (ROIs) containing healthy trabecular bone in the posterior periapical area were selected. The FD of each ROI on the original and compressed images was calculated using differential box counting method. Both image compression and analysis were performed by a public domain software. Altogether, the FD of 220 ROIs was calculated. FDs were compared using ANOVA and Dunnett tests. The FD decreased gradually with compression level. A statistically significant decrease of the FD values was found for JPEG 10, JPEG2000 10, and JPEG2000 30 compression levels (p < 0.05). At comparable file sizes, the JPEG induced a smaller FD difference. In conclusion, lossy compressed images with appropriate compression level may be used for FD calculation.

Use of Fractal Analysis for the Discrimination of Trabecular Changes Between Individuals With Healthy Gingiva or Moderate Periodontitis

BACKGROUND The aim of this study is to evaluate the capability of fractal analysis to discriminate the changes in the trabecular structure of interdental bone between individuals with healthy gingiva or moderate periodontitis using digital images. METHODS Two groups of patients were included according to the probing depth, bleeding on probing, and clinical attachment level. The first group (n = 50) consisted of individuals with healthy gingiva, whereas the other group consisted of patients with moderate periodontitis (n = 50). Periapical images obtained with a storage phosphor plate system during clinical examination were used for the fractal dimension (FD) calculations. Two rectangular regions of interest (ROIs) were placed at mandibular posterior interdental bone areas. The mean of the two ROIs was used to calculate mean FD by using the box-counting method. Student t test was used for the comparison of the FDs of the two groups (P = 0.05). RESULTS The mean FD of patients with periodontitis was 0.83, whereas it was 1.02 for the patients with healthy gingiva. A significant difference was obtained in the mean FD values of healthy individuals and patients with moderate periodontitis (P <0.05). CONCLUSION Fractal analysis can quantitatively discriminate the trabecular integrity alterations induced by periodontitis and therefore can be recommended for the diagnosis and monitoring of changes in trabecular architecture associated with periodontitis.

Diagnostic accuracy of Digora Optime storage phosphor plates for proximal subsurface demineralization: effect of different exposure times

OBJECTIVE The aim of this study was to compare the diagnostic accuracy of F-speed film and storage phosphor plate (SPP) exposed with different exposure times for the detection of artificial enamel subsurface demineralization. STUDY DESIGN Standard enamel windows of extracted premolars were exposed to a demineralizing solution. All teeth were radiographed before and after acid application with F-speed films and SPPs. Films were exposed for 0.25 seconds and SPPs were exposed using 4 exposure times. Receiver operating characteristic analysis was used for diagnostic accuracy (A(z)). RESULTS Significant differences were obtained among A(z)s of 0.08- versus 0.12-seconds and 0.10- versus 0.12-second exposed SPPs (P < .05). A(z)s of films were higher than the SPPs exposed with 0.08, 0.10, and 0.12 seconds (P < .05). No difference was found between the A(z)s of the 2 systems when SPPs were exposed for 0.16 seconds (P > .05). CONCLUSIONS Diagnostic accuracy of films and SPPs was not impaired when exposure time was 36% reduced for the latter; however, diagnosis was impaired when reduced 52%.

Fractal Dimension And Mandibular Cortical Bone Index Evaluations In Normal And Osteoporotic Patients

Introduction: To evaluate the radiographic changes of mandibular bone texture in patients receiving bisphosphonate therapy and to compare with healthy controls. Methods: Direct digital panoramic images of twenty healthy individuals and twenty patients under bisphosphonate therapy were used for measurements of mandibular cortical width (CW), panoramic mandibular indices (PMI) and fractal dimension (FD). FD was calculated on three regions of interest on each side of the panoramic images (angulus, corpus and inter-dental bone). Three-way ANOVA, TukeyKramer tests and Pearson’s correlation coefficient were used for comparisons. Results: Significant difference was found in FDs of two groups (p=0.0004) and different locations (p=0.0001). The difference in FDs of inter-dental bone areas and corpus mandible was significant (p=0.008), while no difference was found for pair-wise comparisons of other two locations (p>0.05). No difference could be obtained in CW and PMI of two groups (p>0.05). Weak insignificant correlation was found between CW-FD ( p=0.26) and CW-PMI ( p=0.86) while there was an insignificant negative correlation between FD and PMI (p=0.96). Conclusion: FD is a good discriminator of altered mandibular bone texture of patients under bisphosphonate therapy. FD of inter-dental and corpus mandibular bone areas as calculated on direct digital panoramic images could be reliable in screening patients using bisphosphonates.

Detection of artificial demineralization bordering different types of laminate veneers using visual inspection and storage phosphor radiography.

ObjectiveThe objective of this study is to compare the diagnostic accuracy of visual inspection (VI) and storage phosphor plate (SPP) radiography for the detection of artificial demineralization bordering different laminate veneers.Materials and methodsTwenty human maxillary canine teeth were prepared. All-ceramic (A) and hybrid ceramic (H) laminate veneers were fabricated and luted. Veneered teeth were covered except for a circular window on the proximal surface bordering restorations. Teeth were kept in acetic acid buffer to create demineralization and imaged with a SPP system. Ten observers evaluated all teeth first visually then with SPP images for the presence/absence of demineralization. Teeth were examined using scanning electron microscopy (SEM) as well. The accuracy was expressed as the area under the ROC curves (Az). Pair-wise comparisons were performed using two-way ANOVA and post hoc t test (p = 0.05). Fleiss kappa (κ) was used for agreement.ResultsSPP radiography was better than the VI for both veneers (p = 0.004). The Azs of two veneers were different for both VI (p < 0.005) and SPP (p < 0.005). SEM evaluation revealed lesions confined to enamel. κ was fair for H, and fair to moderate for A. Agreement was higher for the radiographic evaluation for both veneers.ConclusionEnamel demineralizations bordering hybrid and ceramic laminate veneers can be detected better with SPP radiography than VI and detectability was better for all-ceramic veneers than the hybrid ceramic ones.Clinical relevanceEarly detection of enamel demineralizations bordering laminate veneers would result in time-saving and less-invasive treatment methods; therefore, SPP radiography may be recommended in clinically suspicious cases since it provides better diagnostic accuracy.