Simulation of three intraoral radiographic techniques in pediatric dental patients: subjective comfort assessment using the VAS and Wong-Baker FACES Pain Raiting Scale.

BACKGROUND: Perception of pain associated with intraoral radiography in pediatric patients was evaluated through statistical comparisons of data obtained using the Wong-Baker FACES Pain Raiting Scale (WBFPRS) and visual analog scale (VAS) scoring. METHODS: A total of 75 pediatric patients aged 6-12 years were included in this study. Simulations of each of three radiological methods (analog films, CCD sensor and phosphorus plates) were performed on 25 pediatric patients. Following the simulations, the meaning of each facial expression on the WBFPRS and the numbers on the VAS were explained to each child. For the comparison between groups, the homogeneity of the variances was tested with Levene's test; because the variances were not homogeneous, Welch's test was used. Tamhane's T2 test was used because the homogeneity assumption was not provided to determine the source of the difference between the groups. RESULTS: When the conventional method was compared to the PSPL (photostimulable phosphor luminescence) method, no significant differences were noted in either the WBFPRS or VAS results (p >0.05). The results obtained from both of the scales were significantly different between the conventional method and the CCD sensor method (p < 0.05). When the PSPL and CCD sensors were compared, a significant difference was observed for the WBFPRS (p < 0.05). It was found the highest level of pain scores when used the CCD sensor method than the analog film and PSPL methods (p < 0.05). CONCLUSIONS: It is expected that digital radiographic techniques will be improved in the future and that their disadvantages will be eliminated, resulting in imaging devices that are more comfortable for pediatric patients.

Digitally Scanned Radiographs versus Conventional Films for Determining Clarity of Periapical Lesions and Quality of Root Canal Treatment.

AIM: To compare digital images of conventional radiographs with the original radiographs for perceived clarity of periapical lesions and the quality of root canal treatment. MATERIALS AND METHODS: One hundred and four intraoral periapical radiographs of patients with endodontically treated teeth were randomly selected. The radiographs were digitized using an MD300 USB X-ray Reader. The digital images were transferred to an HP laptop. Three evaluators compared each conventional radiograph with the matching digital image. The images were ranked for clarity and assessed for diagnostic quality; data were analyzed using the Reliability Calculation "ReCal." Results. Both the digital images and conventional films had comparable clarity and diagnostic quality. Results indicated a moderate agreement between the evaluators. CONCLUSIONS: Conventional radiographs digitized using an MD300 USB X-ray Reader have similar clarity and diagnostic quality in comparison to the original radiographs.

The 'Sharpen' filter improves the radiographic detection of vertical root fractures.

AIM: To compare the diagnostic accuracy of digital enhancement filters in the diagnosis of vertical root fractures. METHODOLOGY: The sample consisted of 40 single-rooted teeth randomly divided into two groups: experimental and control. Vertical root fractures were induced in the experimental group using a universal testing machine. All teeth were individually radiographed with three different horizontal angles using the Digora Optime(®) digital system. Three observers separately examined the original and filtered images (3D Emboss, Negative, Sharpen and Shadow). The area under Receiver Operating Characteristic curve values (Az) for each protocol were compared by one-way anova with post hoc Bonferroni test. The significance level was set at 5%. RESULTS: The highest Az value was obtained using the Sharpen filter, with significant differences from the original and other filtered images (P < 0.05). The 3D Emboss filter had the lowest Az value, which was significantly different from the other filtered images (P < 0.05). CONCLUSION: When using the Digora Optime(®) system, the 'Sharpen' filter is recommended to improve the radiographic detection of vertical root fractures.

Guide to Digital Radiographic Imaging.

This is a resource for clinicians who are considering purchasing a digital imaging system or those already using one who want to optimize its use. It covers selected topics in digital imaging fundamentals, detector technology, image processing and quality assurance. Through a critical appraisal of the strengths and limitations of digital imaging components, the goal of this guide is to contribute to the appropriate use of these systems to maximize the health benefit for patients.

Shall I go digital?

UNLABELLED: Dental radiographic imaging is slowly transferring to digital format. The decision to invest in this new technology should be based on a good understanding of the different types of digital imaging available within the dental field. This article outlines its use in general dental practice, highlighting the pros and cons of the various systems both for intra-oral and extra-oral radiography. CLINICAL RELEVANCE: An understanding of the mechanisms of digital imaging and their associated potential problems are required by any clinician moving to film-less imaging.

[Pseudo-color filter in two-dimensional imaging in dentistry].

Most digital systems that are currently used in two-dimensional imaging in dentistry provide opportunities for different image processing filters. One possible means of enhancing digital radiographic image is pseudocoloring (i.e., color conversion of gray-scale images). Recently, this method has become widely used in digital radiology. The human eye is more sensitive to differences in color than to differences in shades of gray. Theoretically, converting a gray scale intensity level of a digital image into colors could enhance the radiographic information. There have been some studies that applied pseudocoloring of digital radiographic images for the detection of caries and periodontal defects. However, thus far, this method failed to show a significantly improved ability for the detection of these lesions. Further investigations are necessary in order to develop specific algorithms that will increase the validity of pseudocoloring in two-dimensional imaging in dentistry.

Quantitative X-ray phase-contrast computed tomography at 82 keV.

Potential applications of grating-based X-ray phase-contrast imaging are investigated in various fields due to its compatibility with laboratory X-ray sources. So far the method was mainly restricted to X-ray energies below 40 keV, which is too low to examine dense or thick objects, but a routine operation at higher energies is on the brink of realisation. In this study, imaging results obtained at 82 keV are presented. These comprise a test object consisting of well-defined materials for a quantitative analysis and a tooth to translate the findings to a biomedical sample. Measured linear attenuation coefficients ? and electron densities ?e are in good agreement with theoretical values. Improved contrast-to-noise ratios were found in phase contrast compared to attenuation contrast. The combination of both contrast modalities further enables to simultaneously assess information on density and composition of materials with effective atomic numbers Z? > 8. In our biomedical example, we demonstrate the possibility to detect differences in mass density and calcium concentration within teeth.

Optimized marker for template-guided intraoral surgery.

Template-guided intraoral surgery is attracting interest due to its accuracy and convenience. Usually, fiducial markers are used for registration of the different model coordinates for patients or plaster and fabrication coordinates in template-guided dental surgery. The accuracy of markers is important because it is directly related to the accuracy of the template-guide, which ultimately affects the success of surgical results. In this paper, we present the methods of determining optimal marker parameters such as size, shape, and material. We have defined parameters that could potentially influence the accuracy of markers and tested them with various values for each parameter. Experiments were performed to measure repeatability, and we tested accuracy and minimized potential error by comparing the actual and calculated dimensions. As a result, the following optimal marker parameters were identified: 3-mm diameter, positively tapered cylindrical shape, and titanium composition.

A comparison study of image features between FFDM and film mammogram images.

PURPOSE: This work is to provide a direct, quantitative comparison of image features measured by film and full-field digital mammography (FFDM). The purpose is to investigate whether there is any systematic difference between film and FFDM in terms of quantitative image features and their influence on the performance of a computer-aided diagnosis (CAD) system. METHODS: The authors make use of a set of matched film-FFDM image pairs acquired from cadaver breast specimens with simulated microcalcifications consisting of bone and teeth fragments using both a GE digital mammography system and a screen-film system. To quantify the image features, the authors consider a set of 12 textural features of lesion regions and six image features of individual microcalcifications (MCs). The authors first conduct a direct comparison on these quantitative features extracted from film and FFDM images. The authors then study the performance of a CAD classifier for discriminating between MCs and false positives (FPs) when the classifier is trained on images of different types (film, FFDM, or both). RESULTS: For all the features considered, the quantitative results show a high degree of correlation between features extracted from film and FFDM, with the correlation coefficients ranging from 0.7326 to 0.9602 for the different features. Based on a Fisher sign rank test, there was no significant difference observed between the features extracted from film and those from FFDM. For both MC detection and discrimination of FPs from MCs, FFDM had a slight but statistically significant advantage in performance; however, when the classifiers were trained on different types of images (acquired with FFDM or SFM) for discriminating MCs from FPs, there was little difference. CONCLUSIONS: The results indicate good agreement between film and FFDM in quantitative image features. While FFDM images provide better detection performance in MCs, FFDM and film images may be interchangeable for the purposes of training CAD algorithms, and a single CAD algorithm may be applied to either type of images.

Comparison of the delay in processing time and protective plastic cases in two phosphor plate systems.

OBJECTIVE: The purpose of this study was to analyze two phosphor plate systems (PSPs) (Dürr Dental, Digora Optime) according to their scanning delay and protective plastic case performances. METHODS: Two PSPs using an aluminum step wedge were exposed. These plates were placed in three different protective plastic cases (manufacturers' original cases, black case, and white case) before obtaining the radiographs and were then processed immediately and 1, 5, 10, 30, 60, 120, 240, and 480 min after exposure. Mean gray values (MGVs) of the 3rd, 5th, 7th, and 9th steps of the wedges were compared using ANOVA. RESULTS: Statistically significant differences were found between the two PSPs (P < 0.001). ANOVA revealed that the MGVs of four steps of the wedges were significantly different from each other for all scan delays (P < 0.001). MGVs increased with increasing scanning delay, except the group with Dürr plates in their original cases. Reduction in image quality began 5 min after exposure in the other Dürr plate groups. CONCLUSIONS: Within the limitations of the current study, it can be concluded that scanning delay causes a reduction in image quality, and using the manufacturer's original protective case will result in better performance of PSPs.

Evaluating craniofacial asymmetry with digital cephalometric images and cone-beam computed tomography.

INTRODUCTION: The aim of this study was to evaluate craniofacial asymmetry by using 2-dimensional (2D) posteroanterior cephalometric images, 3-dimensional cone-beam computed tomography (CBCT), and physical measurements (gold standard). METHODS: Ten dry human skulls were assessed, and radiopaque markers were placed on 17 skeletal landmarks. Twenty linear measurements were taken on each side to compare the right and left sides and to compare these measurements with the physical measurements made with a digital caliper. To acquire the 2D posteroanterior radiographs, an Extraoral Phosphor Storage Plate (Air Techniques, Chicago, Ill) was used as the image receptor with a Eureka x-ray-Duocon Machlett unit (Machlett Laboratores, Chicago, Ill). Three-dimensional imaging data were acquired from a CB MercuRay (Hitachi Medical, Tokyo, Japan). RESULTS: On average, the right side was larger than the left for most of the 20 distances evaluated in the digital 2D and the CBCT images, and there was poor agreement between the digital 2D images and the physical measurements (kappa = 0.0609) and almost perfect agreement (kappa = 0.92) between the CBCT and physical measurements when individual measurements were considered. CONCLUSIONS: Human skulls, with no apparent asymmetry, had some differences between the right and left sides, with dominance for the right side but with no clinical significance. CBCT can better evaluate craniofacial morphology when compared with digital 2D images.

The use of high-resolution digital imaging technology for small diameter K-file length determination in endodontics.

To assess the reliability of high resolution intra-oral photostimulable storage phosphor (PSP) and complementary metal-oxide semiconductor (CMOS) imaging systems for working length (WL) assessment of small K-files in narrow and curved root canals. Eleven narrow and curved canals from extracted molars were used as pre-test for sample-size calculation. Nineteen canals from four cadavers were used for endodontic length assessment in the final study. Small K-files (ISO size 6, 8, and 10) were introduced into the canals at prepared length. Digital intra-oral radiographs were obtained using high-resolution Vistascan PSP plates and Sigma M CMOS active pixel sensor with a DC X-ray tube at 70 kV, 7 mA, and 0.16 s. Both image series were assessed with and without use of a dedicated endodontic filter. Three observers measured WLs for comparison to the gold standards of a digital millimeter ruler. Multiple regression analysis of the dependent measurements revealed no significant influence of imaging sensor (PSP or CMOS, p = 0.34) and image processing (p = 0.97). For ISO file size, however, there was a significant difference (p = 0.08) at a level of 10%. Observers mostly underestimated lengths using PSP but overestimated them on CMOS. Almost all radiographic measurements (96-98%) were within 2-mm deviation, while 71% to 82% deviated within 1 mm. Dedicated filtering and sensor type did not influence the outcome of WL determination of small file sizes when using high-resolution imaging sensors. WL determination with ISO file 6 did show a significant difference compared to ISO 8 and 10 but mostly for deviations <1.5 mm.

Influence of scanning and reconstruction parameters on quality of three-dimensional surface models of the dental arches from cone beam computed tomography.

The study aim is to investigate the influence of scan field, mouth opening, voxel size, and segmentation threshold selections on the quality of the three-dimensional (3D) surface models of the dental arches from cone beam computed tomography (CBCT). 3D models of 25 patients scanned with one image intensifier CBCT system (NewTom 3G, QR SLR, Verona, Italy) using three field sizes in open- and closed-mouth positions were created at different voxel size resolutions. Two observers assessed the quality of the models independently on a five-point scale using specified criteria. The results indicate that large-field selection reduced the visibility of the teeth and the interproximal space. Also, large voxel size reduced the visibility of the occlusal surfaces and bone in the anterior region in both maxilla and mandible. Segmentation threshold was more variable in the maxilla than in the mandible. Closed-mouth scan complicated separating the jaws and reduced teeth surfaces visibility. The preliminary results from this image-intensifier system indicate that the use of medium or small scan fields in an open-mouth position with a small voxel is recommended to optimize quality of the 3D surface model reconstructions of the dental arches from CBCT. More research is needed to validate the results with other flat-panel detector-based CBCT systems.

[Digital volume tomography in ENT medicine]. / Die digitale Volumentomographie in der HNO-Heilkunde.

Digital volume tomography (DVT) is an advancement of panoramic tomography used in dentistry. DVT enables precise display of fine osseous structures without any disturbing artefacts. This makes its application interesting in the field of the lateral, anterior skull base and paranasal sinuses, as well as for the diagnosis of nasal bone fractures. The tomograms can be completed according to need by volume rendering or panoramic slices within a short time. Assuming they have the appropriate technical qualifications in radiation protection, ENT specialists are even able to perform tomography independently using DVT.

Phosphor plate radiography: an integral component of the filmless practice.

The federal government has mandated that all dental and medical patient records be electronic in 3 years. Practices using film radiography will be unable to comply with this mandate. PSP radiography is not only a surprisingly convenient way to transition from film to digital imaging, it can also greatly enhance the practice's productivity, profitability, and patient satisfaction. Modern, forward-thinking practices will want to take full advantage of PSP's superiority by making this transition now rather than waiting until they are forced to.

Compression and smart coding of offset and gain maps for intraoral digital x-ray sensors.

The response of indirect x-ray digital imaging sensors is often not homogenous on the entire surface area. In this case, calibration is needed to build offset and gain maps, which are used to correct the sensor output. The sensors of new generation are equipped with an on-board memory, which serves to store these maps. However, because of its limited dimension, the maps have to be compressed before saving them. This step is critical because of the extremely high compression rate required. The authors propose here a novel method to achieve such a high compression rate, without degrading the quality of the sensor output. It is based on quad tree decomposition, which performs an adaptive sampling of the offset and gain maps, matched with a RBF-based interpolation strategy. The method was tested on a typical intraoral radiographic sensor and compared with traditional compression techniques. Qualitative and quantitative results show that the method achieves a higher compression rate and produces images of superior quality. The method can be adopted also in different fields where a high compression rate is required.

An exposure indicator for digital radiography: AAPM Task Group 116 (executive summary).

Digital radiographic imaging systems, such as those using photostimulable storage phosphor, amorphous selenium, amorphous silicon, CCD, and MOSFET technology, can produce adequate image quality over a much broader range of exposure levels than that of screen/film imaging systems. In screen/film imaging, the final image brightness and contrast are indicative of over- and underexposure. In digital imaging, brightness and contrast are often determined entirely by digital postprocessing of the acquired image data. Overexposure and underexposures are not readily recognizable. As a result, patient dose has a tendency to gradually increase over time after a department converts from screen/film-based imaging to digital radiographic imaging. The purpose of this report is to recommend a standard indicator which reflects the radiation exposure that is incident on a detector after every exposure event and that reflects the noise levels present in the image data. The intent is to facilitate the production of consistent, high quality digital radiographic images at acceptable patient doses. This should be based not on image optical density or brightness but on feedback regarding the detector exposure provided and actively monitored by the imaging system. A standard beam calibration condition is recommended that is based on RQA5 but uses filtration materials that are commonly available and simple to use. Recommendations on clinical implementation of the indices to control image quality and patient dose are derived from historical tolerance limits and presented as guidelines.

A comparative study of image quality and radiation exposure for dental radiographs produced using a charge-coupled device and a phosphor plate system.

AIM: To investigate the quality of periapical radiographic images produced by two digital dental radiography systems, a charge-coupled device (CCD) and a photostimulable phosphor (PSP) image plate system, and to examine the overall radiation exposure when using these systems in a clinical setting. METHODOLOGY: Patients were randomly allocated to both systems and the resultant radiographs rated for quality. The expected radiation exposure for an investigation was calculated. RESULTS: Overall, 98 images were acquired using the CCD system and 108 with the PSP system. The PSP system produced significantly higher quality (P < 0.001) periapical images compared with the CCD system. The CCD system required significantly more (P < 0.001) repeat exposures to obtain a diagnostic image than the PSP system but at a lower expected radiation exposure. CONCLUSIONS: The image quality was superior using the phosphor plate system. Although more repeat radiographs were required using the CCD system, the images were produced with a lower expected radiation exposure.

Comparing the performance of storage phosphor plate and Insight film images for the detection of proximal caries depth.

OBJECTIVES: To compare proximal caries depth between conventional film images, unenhanced and enhanced storage phosphor plate images. METHOD: Bitewing radiographs were taken on 100 patients presenting for Conservative and Periodontal treatment. Only one bitewing was taken on a patient either the right or left hand side of the patient A DenOptics storage phosphor plate and size 3 Kodak Insight film were simultaneously placed into a Rinn bitewing holder. The Insight film was placed behind the phosphor plate. Both were simultaneously exposed to radiation. The unenhanced phosphor plate images were copied four times. Contrast and brightness were either increased or decreased on the copied images. A five point scale was chosen for proximal caries depth: 0--sound, 1--caries in enamel, 2--caries reaching dentino-enamel junction, 3--caries into dentine, 4--caries in a restored area. The bitewing images were evaluated by 4 clinicians. Images with technical errors were excluded from the study. RESULTS: Altogether 1848 tooth surfaces were evaluated of which 136 surfaces were excluded due to technical errors. The results show that for the detection of proximal caries there is no significant difference in accuracy between unenhanced storage phosphor plate and Kodak Insight film images (p > 0.001). When decreasing both contrast and brightness there was no significant difference in diagnostic accuracy (p > 0.001) between unenhanced and enhanced storage phosphor plate images. More surfaces were analyzed for caries into the dentine on the enhanced images when both contrast and brightness were increased. CONCLUSION: Although contrast-enhanced and brightness-enhanced images retween conventional film, unenhanced and enhanced images.

Comparison of Efficiency and Image Quality of Photostimulable Phosphor Plate and Charge-Coupled Device Receptors in Dental Radiography.

The photostimulable phosphor (PSP) plate and charge-coupled device (CCD) are receptors commonly used for intraoral radiography in U.S. dental schools. However, it is unclear which receptor is more beneficial for radiology education and patient care in an academic setting. The aim of this study was to compare the time efficiency, image quality, and operator performance for student-operated PSP plate and CCD receptors. At one U.S. dental school in 2018, 20 dental hygiene and dental students (n=10 each) were recruited as operators. They each exposed anterior and posterior periapical and bitewing radiographs on dental radiograph teaching and training replica using the PSP plate and CCD as receptors. The time taken to expose the radiographs was recorded. Image sharpness/definition, brightness/contrast, and technical errors, including placement, angulation, and cone cut errors, were evaluated on a three-point scale with 0=non-diagnostic, 1=diagnostic acceptable with minor errors, and 2=perfect diagnostic quality. The results showed that it was generally faster for the students to expose intraoral radiographs with CCDs than with PSP plates, although the difference was not significant (p>0.05). Image quality and technical accuracy, especially angulation, were significantly superior for PSP relative to CCD (p<0.05). This study found that PSP imaging was of higher quality and accuracy than CCD, whereas CCD was more efficient. Dental and dental hygiene students would benefit from being trained on both receptors to be able to adapt to a diversified workplace.