Indirect Digital Imaging Research Articles

The Effect of Gamma Value Alterations for Detecting Vertical Root Fracture in Indirect Digital Radiograph (an In-vitro Study)

Background and Objectives Most digital imaging systems offer a variety of image processing techniques. Due to the importance of the accuracy of these images and their widespread application, this study aims to evaluate the detection of vertical root fracture (VRF) in indirect digital images by changing their gamma values. Subjects and Methods In this study, 23 extracted teeth were prepared as samples from dental clinics in Ahvaz, Iran. The radiographs were obtained from the samples before and after VRF induction. After root canal preparation, a very thin disc was used to divide the teeth into two halves in the buccal-lingual direction to create a VRF. The two halves were re-attached to each other and mounted in in molds filled with a mixture of plaster and sawdust. After processing the images by adjusting their gamma values using low, medium and high settings, the images were viewed by two radiologists for the presence or absence of VRF. Results In all three modes of gamma adjustment, the sensitivity, specificity and overall accuracy of images were high and there was no significant difference between the three modes. Conclusion The high gamma for digital images can used to as a filter to detect VRF. The images with medium and low gamma values are less helpful for detecting VRF

Digital imaging and dental record

One of the most important developments in the field of radiology is that the imaging process has started to take place in the digital environment. The advantages of digital radiography increase the interest of dentists to digital radiography, and nowadays digital systems are replacing conventional systems. The most important reasons for the increase of using the digital systems are the fast access to the image, the quality of the image, and the easy storage and transmission of the image. Nowadays, the clinicians can digitize anything and recall it with the patient. This article presents a review about digital imaging and dental record. The history of digital imaging, direct and indirect digital imaging methods, digital sensors and dental record were reviewed.

The role of software in quality assurance for indirect digital intraoral imaging

The aim of this study was to evaluate inherent image quality and the effects of software changes on image quality by using photostimulable phosphor (PSP) plates. Six new DIGORA Optime PSP plates (Soredex/Orion Corp., Helsinki, Finland) were used to assess inherent image quality and the effect of software settings on image quality. Images of a radiographic phantom were exposed to evaluate dynamic range, spatial resolution, and contrast resolution. Varying sharpness filters and gamma values were adjusted to assess their effects on these parameters. Dynamic range was not affected by software settings. Spatial resolution varied among the raw (i.e., minimally processed) images and increased maximally with application of a sharpness filter of 30. Contrast resolution varied among the plates for the raw images. The gamma value of 0.8 was most consistent at increasing the detection of contrast wells. The findings of our study suggest that the sharpness filter 30 and gamma value of 0.8 may increase the spatial and contrast resolutions of DIGORA Optime PSP images when applied during the scanning process. However, this increase was small. Our results also establish that software manipulation should not be used in an attempt to compensate for data that are not present in the image.

Diagnostic efficacy of direct and indirect digital imaging for approximal caries.

Data sourcesMedline, Embase, LILACS, PubMed, The Cochrane Library and Web of Science databases. A grey literature search was conducted through Google Scholar, where abstracts from the top 100 results (as sorted by search engine relevance) were examined. Hand searching of reference lists only. No language restrictions were imposed.Study selectionStudies that evaluated the efficacy of bitewing and periapical images produced by photostimulable phosphor plate (PSP) and direct digital sensor (DDS) systems for the diagnosis of approximal dental caries in extracted human teeth. Studies were required to have used histologic analysis as the gold standard comparison. Primary outcomes were sensitivity and specificity regarding detection of dental caries.Data extraction and synthesisTwo reviewers independently evaluated the titles and abstracts of studies identified through the search, selecting articles according to established inclusion criteria. The selected articles were subsequently reviewed full-text by the same two authors. Disagreements regarding article inclusion were resolved by consensus with an additional third reviewer. One reviewer performed initial data extraction using a customised data extraction form based on the PICOS principle, with two other authors independently verifying collected information. Risk of bias was assessed independently by three reviewers using the QUADAS-2 checklist. A meta-analysis was performed on the grouped studies that presented suitably homogeneous data to evaluate diagnostic capability for approximal caries in dentine. Results were presented with 95% confidence intervals.ResultsSix studies were included, with four being used for meta-analysis. Methodologies of all studies were considered low risk of bias. Only one study reported a significant difference between PSP and DDS technologies; remaining studies determined that PSP and DDS were comparable in the clinical detection of caries. The meta-analysis sample total was 668 tooth surfaces. All studies reported poor sensitivity and high specificity. For PSP, sensitivity ranged from 15 to 54%, and specificity from 84 to 100%. For DDS, sensitivity varied from 16 to 56%, and specificity from 90 to 100%.ConclusionsDDS and PSP systems are excellent at identifying caries-free surfaces, but both lack sufficient sensitivity to reliably identify surfaces with caries. There is no significant difference between performances of DDS and PSP digital systems for caries detection.

Effect of Self-ligating on Bone Density and Root Surface in Maxilla and Mandiblec

Objective: This study was designed to evaluate radiographically the effect of passive self-ligating bracket on root surface and bone density in both arches.Patients, materials and methods: The present study was conducted on 20 patients which were divided into two groups; the first group includes 10 adolescent patients aged 13-16 years old and the second group includes 10 adult patients aged 18-21 years old. For each arch of the individuals participating; a quadrant was bonded with passive self-ligating brackets and the other quadrant within the same arch was bonded by conventionalbrackets. Standardized reproducible digital panoramic radiographs for each patient were evaluated preoperatively (T0), 6 months (T1) and 1 year (T2) after beginningthe orthodontic treatment. The four permanent canines were evaluated regarding the root length and bone density. An indirect digital image radiographic system was followed in this study to obtain and evaluate bone density and degree of root resorption. Results: There was no statistical significant difference in bone density and root resorptionchanges of the maxillary and the mandibular arches between both age groups. Conclusions: Passive self-ligating brackets tend to have the same effect on the bone density and root surface of both the maxilla and the mandible.

Analysis of blasted rocks fragmentation using digital image processing (case study: limestone quarry of Abyek Cement Company)

One of the inseparable parts of mining activities is blasting which one of its important outcomes is fragmentation. Fragmentation is the first result of blasting that is directly related to the mining costs. There are various methods for determining the degree of fragmentation which are divided into two groups, direct and indirect methods. Among direct methods, sieve analysis and, among indirect methods, observational, empirical and digital image processing methods may be referred. In this study, which dealt with the amount of fragmentation in Pir Ali limestone mine, the digital image processing method and Split Desktop software that is the most efficient software in this respect were used. Three blocks with different blast patterns were analyzed to study the fragmentation phenomenon and, ultimately, the F20, F50 and F80 and top size values for each block were obtained separately. Outputs of the Split Desktop software were obtained in tabular form as well as cumulative grain-size curves. The F80 values for the 2.5 × 2.5 m, 2 × 2.5 m, and 2.5 × 3 m patterns were approximately 65.8, 56, and 70 cm, respectively. Finally, outputs of Split Desktop were compared to the results of the Kuz-Ram experimental model. The F80 values obtained for the 2.5 × 2.5 m, 2 × 2.5 m, and 2.5 × 3 m patterns were 54.9, 43.5, and 62.03 cm, respectively, which were in close agreement with the outputs from the software. It can be concluded that the closer F80 of the blasted rocks to the crusher entrance (60 cm), reduced the production costs, which is an outcome practically realized for the 2.5 × 2.5 m pattern.

A Comparative Study of Different Radiographic Methods for Detecting Occlusal Caries Lesions

Objectives: The aim of this in vitro study was to compare the diagnostic accuracy of different radiographic imaging modalities in detecting occlusal caries lesions. Materials and Methods: Under standardized conditions, 125 extracted human permanent molar teeth with sound or occlusal caries lesions were radiographed using a conventional film system (F-speed), a direct digital imaging system (complementary metal oxide semiconductor sensor), an indirect digital imaging system (photostimulable phosphor plate) and a cone beam computed tomography system (CBCT). Two observers scored the resultant images for the presence or absence of caries. Then, the teeth were histologically prepared and a definite diagnosis was determined by stereomicroscopic assessment. The area under the receiver operating characteristic curve (A_z), sensitivity, specificity and accuracy of each imaging modality were calculated, as well as the intra- and interexaminer reproducibility. Results: For both thresholds, interexaminer agreement were higher for CBCT. For intraexaminer agreement, observers had different scores for both thresholds, but the scores were generally higher for CBCT. Similar A_z values were achieved with all imaging methods at a diagnostic D1 threshold. The A_z values of the CBCT system were found to be statistically higher than those of the other imaging modalities at a diagnostic D3 threshold (p > 0.05); no significant differences were found among the other imaging modalities. All radiographic methods showed similar sensitivities, specificities and accuracy in detecting D1 threshold. The CBCT system showed higher sensitivity and accuracy in detecting dentine lesions. Conclusions: Within the limitations of this study, CBCT exhibited better performance in detecting deep occlusal caries lesions than the other radiographic systems.

Digital Imaging in Dentistry: An Overview

Digital radiography has been available in dentistry for more than 25 years, but it has not replaced conventional film-based radiography completely. This could be because of the costs involved in replacing conventional radiographic equipment with a digital imaging system, or because implementing new technology in the dental practice requires a bit of courage. As use of digital radiography becomes more common, many dentists are wondering if and how they can replace conventional film-based imaging with a digital system. This article presents an overview of the different technologies used for digital imaging in dentistry with a broad overview of the benefits and limitations of digital imaging. The principles of direct and indirect digital imaging modalities, image processing and image analysis will be discussed.

Radiopacity assessment of composite resins through digital systems and InSight intraoral film

Objective: this study aimed to assess the radiopacity of eight composite resins recommended for class II restorations. Materials and method: hence, 2 mm thick and 4 mm in diameter test specimens were made and compared to enamel, dentin, and aluminum using four digital systems: two semi-direct by storage phosphor image plates (SPIP) - Digora™, and DenOptix™, two charged couple devices (CCD) - Sens-A-Ray™ and Computerized Dental Radiograph (CDR™), and radiographic film Kodak Insight IS-21™. The radiographs were scanned to obtain the indirect digital image, and along with direct and semi-direct digital images the radiographic densities were assessed in specific software. The pixel values from the aluminum step wedge were submitted to a linear regression from where the equivalent in millimeters for enamel, dentin, and resins were determined. Results: density means of resins were equal or superior to the means obtained for enamel in all digital systems and the conventional film. SureFil™ resin presented greater numerical radiopacity in all digital systems and the radiographic film. ALERT™ resin showed the smallest radiopacity among the studied resins in all digital systems and radiographic film. ALERT™ and Definite™ were statistically equivalent to enamel in the Sens-A-Ray™ system and in radiographic film. The remaining resins (Charisma™, FillMagic™, P60™, Prodigy™, SureFil™, and Z250™) presented higher radiopacities in comparison to enamel. Only ALERT™ presented radiopacity similar to enamel in other digital systems (CDR™, DenOptix™, and Digora™). In these digital systems, Charisma™, Definite™, FillMagic™, P60™, Prodigy™, SureFil™, and Z250™ were more radiopaque than enamel. Conclusion: all resins showed equal or higher radiopacities of enamel in all assessment systems. There was a statistical correlation between systems CDR™ and Sens-A-Ray™, and between Digora™ and DenOptix™; Sens-A-Ray™ also showed correlation with radiographic film. The percentage of density means equivalent to aluminum millimeters for enamel and dentin were 119.6% and 101.6%, respectively.

Shielding effect of thyroid collar for digital panoramic radiography

To evaluate the shielding effect of thyroid collar for digital panoramic radiography. 4 machines [Orthopantomograph(®) OP200 (Instrumentarium Dental, Tuusula, Finland), Orthophos CD (Sirona Dental Systems GmbH, Bensheim, Germany), Orthophos XG Plus (Sirona Dental Systems GmbH) and ProMax(®) (Planmeca Oy, Helsinki, Finland)] were used in this study. Average tissue-absorbed doses were measured using thermoluminescent dosemeter chips in an anthropomorphic phantom. Effective organ and total effective doses were derived according to the International Commission of Radiological Protection 2007 recommendations. The shielding effect of one collar in front and two collars both in front and at the back of the neck was measured. The effective organ doses of the thyroid gland obtained from the 4 panoramic machines were 1.12 μSv for OP200, 2.71 μSv for Orthophos CD, 2.18 μSv for Orthophos XG plus and 2.20 μSv for ProMax, when no thyroid collar was used. When 1 collar was used in front of the neck, the effective organ doses of the thyroid gland were 1.01 μSv (9.8% reduction), 2.45 μSv (9.6% reduction), 1.76 μSv (19.3% reduction) and 1.70 μSv (22.7% reduction), respectively. Significant differences in dose reduction were found for Orthophos XG Plus and ProMax. When two collars were used, the effective organ doses of the thyroid gland were also significantly reduced for the two machines Orthophos XG Plus and ProMax. The same trend was observed in the total effective doses for the four machines. Wearing a thyroid collar was helpful when the direct digital panoramic imaging systems were in use, whereas for the indirect digital panoramic imaging systems, the thyroid collar did not have an extra protective effect on the thyroid gland and whole body.

A Subjective Assessment of Perceived Clarity of Indirect Digital Images and Processed Digital Images with Conventional Intra-oral Periapical Radiographs

To compare and analyze the perceived clarity and diagnostic value of Conventional periapical Radiographs (CRs) with those of their Digitized Periapical Images (DIs) and Processed Digitized Periapical Images (PDIs) counterparts. Forty two intraoral periapical radiographs of patients with clinically suspected periapical pathosis were made to constitute the group of CRs. These were photographed by using a Canon Power Shot SD500 (7.1 Megapixel) digital camera and the unaltered images were transferred to a computer laptop, to form the group of DIs. Subsequently, the contrast and brightness of these images were modified to represent the group of PDIs. Two experienced oral radiologists independently evaluated 5 specific apical and periapical region parameters of all the 42 CRs, DIs and PDIs for perceived image quality and diagnostic value and graded them on a three point grading scale. Conventional radiographs served as the control. Data were analyzed by using paired t-test and Kappa analysis. The clarity and diagnostic quality of the PDIs were statistically significant as compared to those of their conventional counterparts. In comparison, the DIs group fared badly, with deterioration of the image quality. The interobserver agreement was good and all the results were statistically significant. Indirectly digitizing the radiographs by employing a digital camera and further digitally processing the images resulted in an improvement in their perceived clarity and they enhanced their diagnostic properties.

High-resolution X-ray Imaging Based on Pixel-structured CsI:Tl Scintillating Screens for Indirect X-ray Image Sensors

We introduce the development of pixel-structured screens with a thallium-doped CsI (CsI:Tl) scintillator for indirect digital X-ray imaging sensors. The indirect-conversion detection method based on the pixel-structured CsI:Tl scintillator provides high spatial resolution X-ray imaging without sacrificing the light spread in thick scintillation layers. The scintillation screens were fabricated by using a vacuum deposition process and filling the CsI:Tl scintillating powders into a two-dimensional pixel-structured silicon array. Pixel structures with 100 μm and 50 μm pixel sizes with wall widths of 20 μm and 200 μm thickness were prepared and the fabricated CsI:Tl scintillating powders were filled into the trench of the pixel structure through a vacuum process. The final scintillation screens with 2.5 cm × 2.5 cm size were prepared and directly coupled to a CCD image sensor with an optical lens for performance evaluation of X-ray imaging. The imaging performance of the samples was investigated in terms of the relative light intensity, the X-ray linearity and the spatial resolution under practical X-ray exposure conditions. These preliminary results imply that pixel-structured CsI:Tl scintillating screens show high spatial resolution by less lateral spread of the emitted visible photons within pixel-structured silicon arrays. However, these X-ray detectors still require improved X-ray sensitivity by coating the reflective layer onto an inner silicon wall surface and filling the scintillating power into pixel structures completely.

Pain and stress assessment after retinopathy of prematurity screening examination: A comparison study between indirect ophthalmoscopy and digital fundus imaging

UENPS.30 Neonatal pain — What are we afraid of? Paulina Kobiela⁎, Iwona Domzalska-Popadiuk, Anna Kawinska-Kilianczyk, Iwona Janczewska Medical University, Gdansk, Poland

Comparison of radiographic measurements obtained with conventional an indirect digital imaging during endontic treatment

The aims of this study were to evaluate the quality of indirect digitized radiographic images taken during endodontic procedures and to compare the measurements recorded with this technique to those obtained from conventional radiographs. Two-hundred conventional periapical radiographs taken at the undergraduate Endodontics Clinic of the Dental School of Bauru were digitized. The conventional and indirect digitized images were compared by three examiners as to the quality and accuracy of the measurements recorded during endodontic treatment, in canal length determination, gutta-percha adaptation, lateral condensation and final obturation. The conventional radiographs were observed on a film viewer, surrounded by a dark card, and measured with magnifying glass and a millimeter ruler; the indirect digitized images were evaluated on the Digora® for Windows software, with free utilization of the bright/contrast tool. Unlike the conventional radiographic images, all indirect digitized images were considered as having a high quality. The distance between the filling material and the root apex was 0.117 mm larger, on average, for the Digora® system (p<0.01). The measurements achieved by the investigated radiographic methods were clinically similar and they are thus equivalent. Changes in brightness and contrast of the images using Digora® software improved the diagnosis.

Digitizing radiographic films: a simple way to evaluate indirect digital images

Objectives:This study applied a simple method to evaluate the performance of three digital devices (two scanners and one digital camera) using the reproducibility of pixel values attributed to the same radiographic image.Methods:Using the same capture parameters, a radiographic image was repeatedly digitized in order to determine the variability of pixel values given to the image throughout the digitization process. One coefficient value was obtained and was called pixel value reproducibility.Results:A significant difference in pixel values was observed among the three devices for the digitized images (ANOVA, p<0.00001). There was significant pixel value variability at the same digitization conditions for one scanner and the digital camera.Conclusions:Digital devices may assign pixel values differently in consecutive digitization depending on the optical density of the radiographic image and the equipment. The pixel value reproducibility was not satisfactory as tested for two devices. It is maybe advisable knowing the digitization variations regarding pixel values whenever using digital radiography images in longitudinal clinical examinations.

Evaluation of the linear measurements by conventional radiographs and indirect digital images in the endodontic treatment

A successful endodontic therapy depends on the linear measurements obtained by means of radiographs taken during odontometry and also on the application of the established working length up to the final obturation. The aim of this study was to compare the precision of the linear measurement obtained by means of conventional radiographs and indirect digital images evaluated by the Digora 1.5 software during the different stages of endodontic treatment, as well as to evaluate the tools available on this software. A total of 160 radiographs of single-rooted teeth were obtained from files, which were analysed and divided in 4 groups comprising odontometry, cone fit, condensation and the final obturation. Analyses of the conventional radiographs and digitized images were performed by five previuosly calibrated examiners. A high level of inter and intra-examiner agreement was observed through application of the Kendall coefficient and the correlation index, respectively. In relation to the results of linear measurement, the two-way variance analyses and the Tukey test revealed that, concerning the method, a statistically significant decrease was observed on the measurement obtained through the digital method when compared to the conventional radiograph (p<0,05). Moreover, the measurement presented a statistically significant difference among the different stages of endodontic treatment. Regarding interpretation of the digitized image, there was a statistically significant preference towards the Brightness and Contrast tool of the Digora 1.5 software, as evaluated through the Friedman test. The present study demonstrated that image processing by the digital method aids the radiographic interpretation and consequently the determination of reference points for the achievement of the small linear measurements of endodontic treatment. The digital image provided statistically significant smaller linear measurements than those obtained by the conventional method.

Preparation and characterization of pixelated phosphor screens for high-resolution linear imaging in the vacuum ultraviolet and x-ray ranges

Indirect digital imaging sensors employ tailored phosphors screens to convert incident x-ray or vacuum-ultraviolet (VUV) photons to visible light quanta A convenient method to prepare pixelated phosphor screens that can be easily tailored in thickness, type, and spatial resolution is presented. The characterization and evaluation of these screens in the laboratory is addressed and their application to high-resolution VUV and x-ray cameras is discussed.

X-ray Sensitivity of Hybrid-type Sensor based on CaWO4-Selenium for Digital X-ray Imager

The development of digital x-ray detector has been extensively progressed for the application of various medical modalities. In this study, we introduce a new hybrid-type x-ray detector to improve problems of a conventional direct or indirect digital x-ray image technology, which composed of multi-layer structure using a CaWO phosphor and amorphous selenium (a-Se) photoconductor. The leakage current of our detector was found to be ∼180 pA/cm at 10 V/m, which was significantly reduced than that of a single a-Se detector. The x-ray sensitivity was measured as the value of 4230 pC/cm/mR at 10 V/m. We found that the parylene thin film between a CaWO phosphor and an a-Se layer acts as an insulator to prevent charge injection from indium thin oxide (ITO) electrode into an a-Se layer under applied bias.ጊ缀Ѐ㘰〻Ԁ䭃䑎䷙᜕౔6㔱⸸㬅K䍄乍

Radiation doses of digital cephalometric radiography

Aim The aim of this study was to measure organ doses and calculate the effective dose for indirect and direct digital cephalometric exposures. Material and methods Indirect digital cephalometric exposures were made of a Rando® phantom head using a Cranex Tome® multipurpose unit with storage phosphor plates from Agfa and the direct digital (Charge Coupled Device, CCD) exposures were made with a Proline Ceph CM® unit. Exposure settings were 70 kV and 4 mAs for indirect digital exposures. Direct digital exposures were made with 70 kV, 10 mA and a total scanning time of 23 s. TLD700® dosemeters were used to measure organ doses, and the effective doses were calculated with (effective dosesal) and without inclusion of the salivary glands. A pilot study was carried out to compare diagnostic image quality of both imaging modalities. Results Effective doses were 1.7 μSv for direct digital and 1.6 μSv for indirect digital cephalometric imaging. When salivary glands were included in the calculation, effective dosessal were 3.4 μSv and 2.2 μSv respectively. Organ doses were higher for direct digital imaging, except for the thyroid gland, where the organ doses were comparable. Diagnostic image quality of indirect and direct digital cephalometric images seemed comparable. Conclusion Effective dose and effective dosesal were higher for direct digital cephalometric exposure compared with indirect digital exposure. Organ doses were higher for direct digital cephalography. From preliminary data, it may be presumed that diagnostic image quality of indirect and direct digital cephalometric images are comparable.

Subjective image quality of digital panoramic radiographs displayed on monitor and printed on various hardcopy media

The subjective image quality of panoramic radiographs shown on a diagnostic computer monitor were compared with professional direct thermal prints and with common inkjet prints on different paper qualities. Indirect digital panoramic radiographs were obtained from 15 patients. The images were printed with a direct thermal printer in their original format. Afterwards, these were loaded in an imaging software programme (Microsoft Photo Editor) and assessed both on computer monitor and inkjet prints on transparency, glossy, satin and regular paper. Five observers assessed subjective image quality for different regions and anatomical landmarks on a 5-point rating scale. Data were statistically analysed and inter- and intra-observer performances were calculated. Best image quality was obtained with direct thermal prints, followed in descending order by panoramic images viewed on the monitor, inkjet prints on transparencies, glossy paper, satin paper and finally regular paper. The differences were significant except for monitor images versus direct thermal prints, inkjet-transparencies and inkjet-glossy images and inkjet-satin versus inkjet-glossy images. The subjective image quality of indirect digital panoramic images is different for images shown on the computer monitor and for printed images depending on both the printer and paper type used.