Zerstörungsfreie präklinische Evaluation der Wurzelkanalanatomie menschlicher Zähne mittels Flächendetektor-Volumen-CT (FD-VCT)

Sensitivity of conventional radiographs and cone-beam computed tomography in detecting the remaining root-canal filling material

This study aimed to compare the sensitivity of radiographs and flat-panel volume-computed tomography (fpVCT) in detecting the remaining root-canal filling material. Thirty-two root canals in extracted human mandibular molars were prepared and obturated with gutta-percha and sealer. The filling material was removed, and the teeth were split longitudinally. Radiographs and fpVCT scans were obtained and digitized. Virtual images were developed using reconstruction software and then superimposed, and the remaining filling material was outlined. Direct observation of the split root halves using flatbed scans served as a control. The presence and extension of the remaining filling material were evaluated. Statistical analysis was conducted using chi-squared test (P < 0.05). A total of 116 remnants were detected in the flatbed scans, 81 in the fpVCT scans, and 90 in the radiographs, with no significant difference between the radiograph (78%) and fpVCT (70%) results (P = 0.18). In the fpVCT scans, 42% of the remnants exhibited the same dimensions as the control, whereas 27% appeared larger and 30% appeared smaller. In the radiographs, the dimensions of the remnants were identical to the control in 64% of cases, smaller in 29%, and larger in 7%. FpVCT did not exhibit better performance than dental radiographs in detecting the remaining root-canal-filling material: the extension of remnants was indicated correctly in the fpVCT in fewer than 50% of the samples.

Detection and size differentiation of simulated tooth root defects using flat-panel volume computerized tomography (fpVCT)

OBJECTIVE

Our aim was to evaluate the capacity of flat-panel volume computerized tomography (fpVCT) to enable the observer to detect and differentiate 3 different sizes of simulated tooth root defects in radiographs.

STUDY DESIGN

Three simulated tooth root defects of different sizes and a defect-free area (160 sites in total) were randomly distributed on the buccal and lingual surface of 20 mandibular premolar roots of Sus scrofa domestica with round burs. For the imaging of the specimens, an fpVCT prototype was used. Findings were evaluated by 3 observers.

RESULTS

Cavity 0 (no lesion) was correctly identified in 53%, cavity 1 in 69%, cavity 2 in 96%, and cavity 3 in 89%. Altogether, the simulated cavities were classified in a correct manner in 77%. The values were compared using receiver operating characteristic curves. The area under the curve (AUC) for cavity 0 versus the pooled results for cavities 1-3 was found to be 0.72. The AUC for the pooled results for 0-2 (no pathologic impact) versus cavity 3 (potential pathologic impact) was 0.94. There was no significant dependence of the results on the observer (P = .37). Results with P < .05 were considered to be significant.

CONCLUSIONS

Flat-panel volume computerized tomography, which is currently used only as a research tool, has a high potential in detection and differentiation at an early stage of external root resorption cavities with pathologic relevance..

Digital and Advanced Imaging in Endodontics: A Review

This review provides an overview of digital radiography as it exists, including advanced imaging such as computed tomography (CT), cone beam volumetric imaging, and micro-CT as relevant to the practice of endodontics. An evidence-based approach to adoption of different imaging technologies is included to assist the practitioner with the selection process of imaging modalities. Commonly used imaging terminology is introduced, as well as the advantages and disadvantages of image processing. New image reconstruction techniques have been introduced that provide information three-dimensionally to the clinician for routine endodontic and surgical treatment planning. The age of three-dimensional imaging and image processing is here. Limitations and advantages of newly introduced imaging modalities are discussed briefly.

Erste Erfahrungen mit einem Flächendetektor-Volumen-CT (fpVCT) in der experimentellen Osteoporosediagnostik am Kleintiermodell

BACKGROUND

Flat-panel volumetric computed tomography (fpVCT) is a new, noninvasive CT imaging modality with increased isotropic resolution. Technical details, potential applications, and our initial experience with a fpVCT prototype scanner in the imaging of osteoporosis in a rat model are presented.

METHODS

To date, 21 rats have been investigated in vivo with fpVCT. Pharmacologic effects on bone mineral density (BMD) and structure were of special interest. Image evaluation focussed on the second lumbar vertebra and the left femoral bone. To validate measurement results, BMD values calculated with fpVCT were correlated with results of BMD measurements from ashing of the second lumbar vertebra and femoral bones.

RESULTS

Our initial results show that fpVCT is capable of detecting differences in BMD between ovariectomized rats treated with estradiol and a control group with high statistical significance (p<0.05), corresponding to ashing as the gold standard.

CONCLUSIONS

In a rat model, fpVCT imaging is especially useful in longitudinal in vivo investigations of BMD measures. Spatial resolution of up to 150 microm allows imaging of the trabecular structure only in human cadaveric bones.

Volumetry of human molars with flat panel-based volume CT in vitro

The flat panel-based volume computed tomography (fpVCT) is a new CT device applicable for experimental, three-dimensional evaluation of teeth at a resolution of about 150 microm in the high contrast region. The aim of this study was to investigate whether fpVCT was suitable for quantification of the volumes of dental hard tissues and the root canal system to establish a new method for morphological studies. Fifty-two extracted third molars (maxillary: 31, mandibular: 21) were examined with a prototype of an fpVCT using a volumetry algorithm at different levels according to the radiographic density of enamel and dentine. Volumetry of the root canal system was performed after "region growing segmentation": starting from a voxel in the centre of the root canal, this algorithm searches voxels of same density in the surrounding. The volumetry of the root canal system was stopped by the investigator at the apical constriction. Results showed that dentine, enamel and root canal system could be well distinguished in three-dimensional images. Volumetry yielded the following data (cm(3), mean+/-SD): dentine 0.438+/-0.111, enamel 0.227+/-0.051, root canal system 0.052+/-0.017 and total volume 0.753+/-0.159. In conclusion, the fpVCT is appropriate for non-destructive volumetry of large numbers of teeth in experimental laboratory studies.