Intraoral Radiographic System Research Articles

Improvements in image quality after optimization in digital intraoral radiographs

BackgroundDigital intraoral radiographic exposures are optimized largely on the basis of subjective assessment of diagnostic image quality. This study presents an objective approach to optimize radiographic exposure settings for digital intraoral radiographic systems. MethodsSeven size 2 digital intraoral systems were assessed for image quality and determination of optimal exposure following the protocol specified in American National Standard Institute/American Dental Association Standard No. 1094: Quality Assurance for Digital Intra-Oral Radiographic Systems. A ProX radiograph unit (Planmeca) at 63 kVp and 6 mA was used to obtain radiographs of the Dental Digital Quality Assurance phantom. ImageJ software (National Institutes of Health) was used to quantify dynamic range and spatial resolution, and contrast perceptibility was evaluated visually. Optimal exposure is the setting with the maximal contrast perceptibility and spatial resolution while displaying the full dynamic range. After image optimization, a custom phantom consisting of an endodontically prepared tooth was imaged to evaluate the file position relative to the apex for each system. Differences in distances between file position relative to the root apex at the optimal exposure as well as 1 increment above and below were measured. ResultsRadiographic images obtained at the optimal exposure yielded better visualization and more accurate measurements of the file tip relative to the apex. ConclusionsOptimizing radiographic exposures improves image quality and accuracy in clinical decisions. Practical ImplicationsImprovement in image quality and better accuracy in actual distance of the endodontic file to the radiographic apex coupled with complete cleaning, shaping, and obturation of the canal should lead to better endodontic treatment outcomes.

Effectiveness of image optimization in digital intraoral radiographic systems

<h3>Objective</h3> To evaluate the effectiveness of image optimization in digital intraoral radiographic systems. <h3>Study Design</h3> Radiographic images from seven size 2 intraoral sensors (Carestream 6200, Dexis Platinum, Gendex GXS700, LEDTuxedo, Planmeca ProSensor HD, Sirona Schick 33, and XDR Radiology) were optimized in accordance with ANSI/ADA Standard 1094 Quality Assurance for Digital Intra-Oral Radiographic Systems to investigate the benefits of image optimization. The Dental Digital Quality Assurance (DDQA) phantom provided reference objects for assessment of dynamic range, spatial resolution, and contrast perceptibility. Images were analyzed with NIH ImageJ to objectively assess dynamic range and spatial resolution. Contrast perceptibility was subjectively scored based on the visibility of individual wells in two rows of the DDQA phantom. All radiographic images were acquired with the same DC x-ray source (Planmeca ProX) using the sensor's native software on a Gigabyte Laptop Model P34 with a display calibrated using the SMPTE monitor test pattern. To simulate clinically relevant scenarios, a second phantom of an endodontically prepared molar tooth was fabricated, consisting of a #6 K endodontic file placed to the apex of the palatal root of a maxillary molar. File position was confirmed using a scanning electronic microscope and then fixed in place within the root canal. The instrumented tooth was stabilized in acrylic to simulate soft tissue and bone absorption. Three exposures of the endodontic phantom were made using each sensor: one at the optimal exposure time and two at exposure settings one increment above and below. ImageJ was used to measure the distance from the file tip to the radiographic apex. <h3>Results</h3> While optimal exposure parameters varied among sensors, in all cases, the measured distance from the endodontic file to the apex was superior on images acquired at optimum exposure rather than radiographic images acquired with exposures just one increment higher or lower than the optimal parameters. <h3>Conclusion</h3> Optimization of radiographic images using the approach specified in ANSI/ADA Standard1094 enhances clinical diagnostic accuracy. <b>Statement of Ethical Review</b> Ethical Review or exemption was not warranted for this study

Long cone versus short cone for digital intraoral radiographic imaging

<h3>Background</h3> Intraoral radiographs are acquired by one of two methods: the long cone paralleling technique that uses a 30 cm distance from the focal spot to the end of the beam indicating device (BID) versus the short cone technique of 20 cm. The long cone paralleling technique (LCPT) reduces x-ray beam divergence, scatter radiation, penumbra, and magnification as well as entrance skin exposure. LCPT has been recommended for use with digital intraoral radiographic imaging. However, most intraoral generators are supplied with only a short cone BID. <h3>Objective</h3> This research project evaluated image quality of digital radiographs acquired with both long cone and short cone techniques. <h3>Study Design</h3> A series of incrementally increasing exposures of a digital intraoral quality assurance phantom was acquired with both long and short cone methods over a range of exposures from 10 ms to 800 ms to encompass all exposures in the clinical range. Image quality was evaluated using a scientifically validated method that has been published in other research studies on digital intraoral image quality. The image quality parameters assessed were dynamic range, contrast perceptibility, and spatial resolution as specified in ANSI /ADA Standard No. 1094 Quality Assurance for Digital Intra-oral Radiographic Systems. Images were visually evaluated and then objectively evaluated using the NIH ImageJ software for validation. <h3>Results</h3> The results support the use of the LCPT for the acquisition of digital intraoral radiographic images. <h3>Conclusion</h3> The additional purchase of the BID extension is substantiated by the results. <b>Statement of Ethical Review</b> Ethical Review or exemption was not warranted for this study

The importance of the ANSI ADA Standard for digital intraoral radiographic systems—a pragmatic approach to quality assurance

The need for quality assurance (QA) for digital dental radiography has existed since the introduction of digital imaging; however, the methods and phantoms required to achieve it were not available. This resulted in a chaotic approach to address QA based largely upon subjective analysis of image quality. The American National Standards Institute (ANSI)/American Dental Association (ADA) Quality Assurance Standard 1094 for Digital Intraoral Radiographic Systems (DIRS) presents a paradigm shift to a scientific and objective method of QA rather than one based on subjective assessments. This standard takes into account the contributions of all components of the digital imaging chain that affect final image quality rather than assessing the various components in isolation. The optimal image is determined for each DIRS through objective analysis of the image quality properties of dynamic range, spatial resolution, and contrast perceptibility. Image optimization, a critical component of a quality assurance program, is the proper balance between diagnostic image quality and radiation dose to the patient. This publication counters disseminated myths and misconceptions with scientific evidence and will help dental practitioners appreciate and understand the benefits of the new ANSI/ADA Standard on QA for DIRS.

The impact of digital filters on the diagnosis of simulated root resorptions in digital radiographic systems.

To evaluate the influence of digital filters of intraoral radiographic systems on the diagnosis of simulated internal and external root resorptions and image quality. Internal root resorption (IRR) and external root resorption (ERR) were simulated in 34 teeth. For image acquisition, two radiographic systems were used: Digora Toto and VistaScan. All filters available in these systems were applied. Three observers scored the detection of root resorptions in a 5-point scale. The noise and the contrast-to-noise ratio (CNR) were calculated. The area under ROC curve, sensitivity, specificity, and accuracy were obtained. One-way ANOVA with Tukey's post hoc tests compared the diagnostic values, noise, and CNR between the filters (α = 0.05). For ERR, there were no significant differences in diagnostic values between the filters tested for both systems. For IRR, Original and Noise Reduction filters presented higher sensitivity than the Sharpen2 filter for images from Digora Toto, with no differences between the other groups. For VistaScan, there were no significant differences of diagnostic values between the groups studied. Noise values differed among the filters of both systems. The CNR of the filters differed only for the bone region for Digora Toto, while for VistaScan, both tooth and bone regions differed. Despite promoting changes in pixel intensities and affecting the noise level of the radiographic images, the digital filters of Digora Toto and VistaScan systems do not affect the diagnosis of internal or external root resorptions. Digital filters are common tools in digital radiographic systems and may be used by the professional without impairment in root resorptions diagnosis.

Automatic exposure compensation in intraoral digital radiography: effect on the gray values of dental tissues

BackgroundThis study aimed to investigate the effect of automatic exposure compensation (AEC) of intraoral radiographic systems on the gray values of dental tissues in images acquired with or without high-density material in the exposed region using different exposure times and kilovoltages. The influence of the distance of the high-density material was also investigated.MethodsRadiographs from the molar region of two mandibles were obtained using the RVG 6100 and the Express systems, operating at 60 and 70 kV and 0.06, 0.10, and 0.16 s. Subsequently, a titanium implant was inserted in the premolar’s socket and other images were acquired. Using the ImageJ software, two regions of interest were determined on the enamel, coronary dentine, root dentine, and pulp of the first and second molars to obtain their gray values.ResultsIn the RVG 6100, the implant did not affect the gray values (p > 0.05); the increase in kV decreased it in all tissues (p < 0.05), and the exposure time affected only the root dentine and pulp. In the Express, only enamel and coronary dentine values changed (p < 0.05), decreasing with the implant presence and/or with the increase in exposure factors. The distance of the implant did not affect the results (p > 0.05).ConclusionsAEC’s performance varies between the radiographic systems. Its effect on the gray values depends not only on the presence or absence of high-density material but also on the kV and exposure time used.

Applying the New ADA Quality Assurance Standard to Digital Intraoral Radiographic Systems

This article is intended to describe the appropriate quality assurance (QA) methods for digital intraoral radiographic systems in accordance with ANSI/ADA Standard 1094. This article goes step by step through the digital imaging chain (the intraoral X-ray generator, the image receptor and acquisition software and the image display device), so the reader can achieve a complete understanding of what is required to successfully implement a comprehensive QA protocol within their own practice.

Comparación de la precisión diagnóstica de la tomografía computarizada de haz cónico y tres sistemas radiográficos intraorales en la detección de lesiones de caries in vitro.

Objective: The objective of the study was to compare the diagnostic accuracy of cone beam computed tomography and three intraoral radiographic systems in the detection of in vitro caries lesions. Material and Methods: One hundred teeth (46 molars and 54 premolars) were evaluated, including 176 proximal surfaces and 90 occlusal surfaces, with or without dental caries lesions. Digital images of all teeth were obtained using specific intraoral radiographs, VistaScan DürrDental®phosphor-plate radiography, XIOS XG Sirona® digital sensor radiography, and CBCT I-CATTM. Observers evaluated the images for the detection of caries lesions. The teeth were clinically sectioned and stereomicroscopy served as a validation tool. The relationship of sensitivity and specificity between all systems was determined through the ROC curve using Az values. Results: The values of the area under the curve (Az) selected for the CBCT I-CATTM system were 0.89 (0.84-0.93), for conventional radiography 0.71 (0.66-0.76), digital sensor radiography 0.74 (0.70-0.78) and digital radiography with phosphor-plates 0.73 (0.69-0.77). Statistically significant differences were found between the CBCT I-CATTM system and intraoral radiographic systems (p&lt;0.01). The sensitivity and specificity values for the CBCT I-CATTM were 0.84 and 0.93 respectively. Conclusion: CBCT has a high sensitivity and specificity compared to intraoral radiographic systems for the diagnosis of dental caries lesions in vitro.

Effect of differences in pixel size on image characteristics of digital intraoral radiographic systems: a physical and visual evaluation.

To quantify and validate the effect of pixel size on a digital intraoral radiographic system according to International Electrotechnical Commission standards through physical and visual evaluations. The digital intraoral radiographic system used was the photostimulable phosphor imaging plate and scanner system. The system had three image capture modes: high-speed (HS), high-resolution (HR), and super high-resolution (SHR) with different pixels. The physical characteristics of the system were evaluated using presampled modulation transfer function (MTF) and the normalized noise power spectrum (NNPS). An aluminum (Al) step phantom with different depths of holes was used to acquire images under various exposure conditions. The average number of perceptible holes from all steps was plotted against each exposure dose. The results were compared to analyze the effects of pixel size on image quality of intraoral radiographs. The MTF was slightly higher with SHR than with HR and HS. The NNPS with SHR showed about a 40% decrease in magnitude compared to HS. The total number of perceptible holes in the Al step phantom was higher with SHR than with HS and HR in all exposure conditions. The MTF and NNPS obtained with different pixel size could be quantified by physical evaluation, and the differences were visually validated with Al step phantom. The SHR mode has the potential to decrease the radiation dose without compromising the image quality.

Diagnostic Validity of Cone Beam Computed Tomography Radiography in Detection of Dental Caries

Introduction: Comparison between tomography and one or more digital intra-oral systems have been conducted with histological sectioning of the offending teeth as gold standard for comparison. The findings in the literature are contradicting, since some studies showed superiority of tomography. This systematic review aimed at evaluating the evidence in relation to the diagnostic accuracy of cone beam computed tomography compared to the digital and film-based intra-oral radiography. Methods: An electronic search was conducted on Medline Plus, PubMed, Science Direct, and Wiley databases. All articles published in English language up to October 2017 were eligible to be included in this review. Search on different search engines and different database websites including hand search revealed 496 articles. After reading titles and abstracts, irrelevant and duplicated articles 459 were excluded. The resulting articles were read carefully for comparison of accuracy between CBCT and other intra-oral radiographic systems and the references lists of the resulting articles were screened for additional studies. Results: A total of 22 articles, available according to the inclusion criteria, were included in this systematic review. Most of the studies (13 articles) were conducted on premolars and molars while, 5 studies were conducted on molars, one study was conducted on premolars, one study was on incisors, and two studies did not report the type of teeth used. The majority of the studies (21articles) were laboratory experiments (in-vitro) while, only one study was in-vivo. The sample size for the studies (number of teeth) ranged from 30 to 257 teeth. Conclusions: CBCT has similar diagnostic accuracy as other intra-oral systems for diagnosing dental caries. CBCT is not recommended for caries diagnosis unless the CBCT was undertaken for any other procedures where the dental caries should be included in the final report.

&lt;b&gt;Evaluation of the optical density of composite resins with the use of nanotechnology by means of intraoral radiographic system (CMOS)

The aim of this study was investigate the optical density of four different brands of composite resins of nanotechnology. The composite resins Estelite Sigma Quick ® (Tokuyama), Esthet –X HD ® (Dentsply), 4 Seasons ® (Ivoclar Vivadent) and Filtek Z350XT TM (3M-ESPE) were inserted into cavities in transparent acrylic sheets, separated by thickness into 1, 2 and 3 mm. The images were imported into the software ImageTool ® 3.0 (UTHSCSA, EUA). Data were submitted to ANOVA and Tukey. The mean values of the composite resins 4 Seasons ® (2.71±0.20) and Filtek Z350XT TM (2.64±0.26) did not differ statistically for samples with thickness of 1 and 2 mm. However, for both thickness Estelite Sigma Quick ® (1.92±0.11) and Esthet-X HD ® (3.57±0.29) showed significant differences compared to the other composite resins (p = .012). All 3 mm-thick samples showed significant differences among themselves (Estelite Sigma Quick ® p < .001, Esthet-X HD ® p < .001, 4 Seasons ® p=.001 and Filtek Z350XT TM p = .003). Conclusion: Among the three thicknesses evaluated, Estelite Sigma Quick ® showed the lowest optical density, whereas the highest values were observed for Esthet X HD ® . The resins are studied according to the rules of optical density value thus being favorable clinical use.

Evaluation of image quality parameters of representative intraoral digital radiographic systems

The aim of this study was to compare imaging properties of 20 intraoral digital systems objectively. Using a direct current x-ray source and a radiographic phantom, a series of radiographs was made from the lowest exposure time until the sensor saturated. Images were captured and stored. Incident exposures were measured using a radiation meter. Gray scale, spatial resolution, and contrast/detail detectability were evaluated. Presence of 7 distinct steps spanning the gray levels from 0 to 255 was used to define the exposure latitude. An "optimal" exposure, the lowest exposure where maximum spatial resolution and contrast/detail detectability were achieved, was determined. The systems varied greatly in latitude, "optimal" exposure, and image quality. This may not be readily apparent to the naked eye or when clinical images are compared. Objective assessment of image quality with a quality assurance tool makes it possible to evaluate and compare the various intraoral digital systems.

Comparison between intraoral indirect and conventional film-based imaging for the detection of dental root fractures: anex vivostudy

Digital intraoral radiographic systems have been rapidly replacing conventional dental X-ray films for diagnosis of dental diseases. Current scientific literature supports the use of these digital systems for the detection of dental caries, periodontal bone loss, and periapical pathologies. However, relatively few studies have been published addressing the detection of dental root fractures. The purpose of this study was to compare the intraoral F-speed film (Insight) with two photostimulable phosphor (PSP) indirect digital systems (ScanX and Digora Optime) for the detection of simulated dental root fractures. Ten raters evaluated images acquired from 10 dry human cadaver mandibles under optimal viewing conditions. These data were analyzed by a 5-point receiver operating characteristic curve analysis for statistical differences. Sensitivity and specificity of these systems were also assessed. Since statistically significant difference between the systems was not observed, the results of this study agreeably support indirect digital PSP plates as an alternative to the evaluated conventional film for the detection of dental root fractures.

Alternative X-ray filters for an intra-oral digital radiographic system

The aim of this study was to evaluate the effect of the modulation of the radiation spectrum with the use of alternative X-ray filters in the quality of intra-oral digital images from storage phosphor plates. The radiographic exposures were performed in a GE 1000 X-ray machine (General Electric Co., Milwaukee, WI), operating at 65 kVp, 10 mA, 40 cm focus receptor distance using three different exposure times: 0.05 s, 0.16 s and 0.35 s. The control filter (GC) was 100% aluminium (Al) with a thickness of 1.5 mm. The tested filters were: G1, 97% Al and 3% copper (Cu) with 1.47 mm thickness; G2, 96% Al and 4% Cu with 1.53 mm thickness; G3, 95% Al and 5% zinc (Zn) with 1.56 mm thickness; G4, 98% Al and 2% Zn with 1.5 mm thickness; and G5, 95% Cu and 5% Zn with 1.6 mm thickness. For formation of the image, a 12-step Al wedge (each step with increments of 1 mm in thickness) was radiographed 10 times. Pixel values measured in digital images were converted into optical density (OD). All replicates showed OD with high reproducibility (r > 0.95) for all exposure times and tested filters. In comparison between filters, statistically significant differences in density (p < 0.05) were observed. The OD curve of the G5 filter in all exposure times and G3 filter in an exposure time of 0.05 s showed changes in shape (p < 0.05). Excluding the G5 filter, all others tested filters can be used as a substitute for GC without losses in image quality.

A new method for evaluating perceptible contrast information in digital intraoral radiographic systems

Objectives To evaluate four digital intraoral radiographic systems using perceptibility curves (PCs) in a grayscale domain and to clarify the usefulness of this new method.

Marginal bone levels measured in film and digital radiographs corrected for attenuation and visual response: anin vivostudy

To compare the accuracy and precision of measurements on marginal bone levels in differently processed digital radiographs and in film-based radiographs. Twenty-one patients with a diagnosis of chronic periodontitis were included in this study. Periapical radiographs were exposed with the Dixi digital intraoral radiographic system (Planmeca Oy, Helsinki, Finland) and the F-speed Film (Insight, Eastman-Kodak Co., Rochester, NY), respectively. Digital radiographs were subsequently processed into two sets: (a) correction for attenuation and visual response and (b) the same correction but with an additional shift in grey levels. Patients had periodontal surgery immediately after the radiographs were exposed. The vertical distance from cementoenamel junction to the most apical part of the marginal bone was assessed. The measurements were then employed as reference standard and subtracted by the vertical distance from radiographs accordingly. Altogether, 47 sites were evaluated. Seven observers were employed for evaluation under the same viewing conditions. ANOVA was employed for statistical analysis. No significant differences were found between the absolute differences of the vertical distance obtained from radiographs to their corresponding reference standards when comparing differently processed digital radiographs, but the absolute differences were significantly smaller in digital radiographs than in films. Interobserver variances were not significant. Digital radiographs have a favourable measurement accuracy compared with film radiographs when assessing marginal bone levels.

Patient dose in charge-coupled device-based full-mouth intraoral radiography

Objectives This study investigated the effect of the size of the sensitive area of the charge-coupled devices (CCD) used in digital intraoral radiographic systems on the patient effective dose in full-mouth radiographic examinations.

Performance evaluation and testing of digital intra-oral radiographic systems

Four digital intra-oral radiographic systems were tested and evaluated; three charge-coupled device (CCD) based systems from RVG, Visualix and Sidexis and a photostimulable phosphor (PSP) system from DenOptix. Image quality was assessed using three purpose-built phantoms to measure uniformity, low contrast detail detectability and signal-to-noise ratio (SNR). Limiting resolution was measured using a 20 lp mm(-1) bar pattern. Radiation output inaccuracies caused difficulties in achieving optimum doses for CCD systems. However, the accuracy was improved by using K-edge filters. SNR measurements proved to be a useful tool in assessing system performance. Each system has specific attributes: resolution was highest for the RVG system, the Visualix system measured the highest SNR and the lowest exposure settings were on the Sidexis system. Test methods and phantoms developed are suitable for acceptance testing and commissioning digital dental X-ray systems and for programming each system to produce an optimum level of image quality.

Effects of scintillator on the detective quantum efficiency (DQE) of a digital imaging system

To compare the effects of scintillator on the detective quantum efficiency (DQE) of a charge-coupled device (CCD) digital intraoral radiographic system. Three screens composed of 3 different scintillator materials, namely europium-doped lutetium oxide (Lu2(O3):Eu3+), transparent optical ceramic (TOC), thallium-doped cesium iodide (CsI:Tl; CsI), and terbium-doped gadolinium oxysulfide (Gd2(O2)S:Tb; GOS) were compared, in turn, in combination with a CCD detector having square pixels with height and width dimensions of 19.5 microm. DQE was investigated using the slanted-slit-derived MTF and surrogate signal-to-noise ratio (SNR) measurements derived from calculations of the mean and standard deviations from the mean pixel values of multiple random patches from various uniform exposures. An Irix x-ray generator operated at 70 kVp and 8 mA, with a nominal focal spot size of 0.7 mm and 2.5 mm Al equivalent filtration, was used in making all exposures. Using TOC, the peak DQE was 62% at 5 cycles/mm. For CsI, the peak DQE was 22% at 2 cycles/mm. With GOS, the peak DQE was 10% at 1 cycle/mm. Under identical experimental settings, TOC consistently resulted in higher DQE than CsI and commercially available GOS scintillators combined with the same high-resolution solid-state detector.

Development and evaluation of a CMOS sensor-based digital intra-oral radiographic system

As part of an ongoing investigation into the development of a dental digital radiographic (DDR) system using a complementary metal-oxide semiconductor (CMOS) sensor, this study developed hardware and software with a graphical user interface to acquire and display intra-oral images from a prototype DDR system. The aim of this study was to develop a DDR system using a CMOS sensor and evaluate its characteristics. Electrical signals that were generated by the CMOS sensor were transformed into digital images by a control computer equipped using a USB board. The distance between the X-ray tube and the CMOS sensor was adjusted within the range of 10-40 cm to provide the optimal image quality. In order to evaluate the image quality according to variations in the dose, phantom images (60 kVp, 7 mA) were obtained at exposure times of 0.03, 0.05, 0.08, 0.10, and 0.12 s, and the signal-to-noise ratio (SNR) was calculated from the phantom image data. The modulation transfer function (MTF) was obtained from a Fourier transform of the line spread function, which was itself derived from the edge spread function of a sharp edge image acquired using the exposure conditions of 60 kVp, 7 mA, and 0.08 s exposure time. The best contrast and focus were obtained at 20 cm. The SNR level was found to increase with increasing exposure time ranging from 0.03 to 0.08 s. The results obtained at 10% of the MTF showed that the resolution of the DDR system was approximately 6.2 line pairs per millimeter. The characteristics of the prototype DDR system have potential applications in intra-oral dental radiographic imaging. The fully developed DDR system can be used for making a clinical diagnosis with further improvements in the acquisition time and spatial resolution.