Correlation between spatial resolution and ball distortion rate of panoramic radiography

Comparative analysis of clinical image evaluation charts for panoramic radiography

OBJECTIVE

To compare and analyze professional (P chart) and simple (S chart) clinical image evaluation charts for evaluating panoramic radiograph image quality.

METHODS

Ten evaluators assessed 285 clinical panoramic radiograph images. The evaluators were divided into oral and maxillofacial radiologists (OMFR, n = 5) and general dentist (dentists not specializing in oral and maxillofacial radiology, G, n = 5) groups. For image evaluation, P and S charts provided by the Korean Academy of Oral and Maxillofacial Radiology were used. Scores of items for each evaluation chart were used to compare the reliability, correlation, evaluation scores, evaluation time, and preference, and statistical analyses were performed using IBM SPSS Statistics.

RESULTS

The S chart showed similar levels of evaluation scores at shorter evaluation time, as compared to the P chart. In the results for each evaluation chart, all analyzed correlations were statistically significant. Total score, image density/contrast/sharpness, and overall image quality items showed a very high positive correlation in the P chart. While the overall range of correlation coefficients was relatively lower in the S chart than the P chart, the same items showed high correlation coefficients. In the preference evaluation, both the professional and generalist groups preferred the S chart.

CONCLUSIONS

A comparative analysis with the P chart, revisions, and upgrades are needed for the S chart items that showed low correlations in this study, such as artifacts, coverage area, and patient movement.

Three-dimensional evaluation of a virtual setup considering the roots and alveolar bone in molar distalization cases

We aimed to evaluate root parallelism and the dehiscence or fenestrations of virtual teeth setup using roots isolated from cone beam computed tomography (CBCT) images. Sixteen patients undergoing non-extraction orthodontic treatment with molar distalization were selected. Composite teeth were created by merging CBCT-isolated roots with intraoral scan-derived crowns. Three setups were performed sequentially: crown setup considering only the crowns, root setup-1 considering root alignment, and root setup-2 considering the roots and surrounding alveolar bone. We evaluated the parallelism and exposure of the roots and compared the American Board of Orthodontics Objective Grading System (ABO-OGS) scores using three-dimensionally printed models among the setups. The mean angulation differences between adjacent teeth in root setups-1 and -2 were significantly smaller than in the crown setup, except for some posterior teeth (p < 0.05). The amount of root exposure was significantly smaller in root setup-2 compared to crown setup and root setup-1 except when the mean exposure was less than 0.6 mm (p < 0.05). There was no significant difference in ABO-OGS scores among the setups. Thus, virtual setup considering the roots and alveolar bone can improve root parallelism and reduce the risk of root exposure without compromising occlusion quality.

Nasal cavity perforation by implant fixtures: case series with emphasis on panoramic imaging of nasal cavity extending posteriorly

The nasal cavity is an important landmark when considering implant insertion into the anterior region of the maxillary arch. The perforation of implants into the nasal cavity may cause complications, such as implant migration, inflammation, or changes in nasal airflow; thus, precise assessment of the nasal cavity is mandatory.Three cases of nasal cavity perforation by dental implants are presented, including one case of implant fixture migration into the nasal cavity. On panoramic radiographs of the patients, the following common features were observed: the horizontal radiopaque line of the hard palate was observed to be inferior to or similar to that of the antral floor and the bone between the lateral wall of the nasal cavity and the medial wall of the maxillary sinus was emphasized in a triangular shape.When the maxillary sinus is small and alveolar bone resorption is severe, panoramic evaluation may cause overestimation of the available residual bone, particularly in the maxillary canine/premolar region. Therefore, the residual bone should be reevaluated three-dimensionally to measure the exact bony shape and volume.

Automated measurement for image distortion analysis in 2D panoramic imaging of dental CBCT system: A phantom study

INTRODUCTION

The daily image quality assessment involves large datasets that consume a lot of time and effort. This study aims to evaluate a proposed automated calculator for image distortion analysis in 2-dimensional (2D) panoramic imaging mode for a dental cone beam computed tomography (CBCT) system in comparison with present manual calculations.

METHODS

A ball phantom was scanned using panoramic mode of the Planmeca ProMax 3D Mid CBCT unit (Planmeca, Helsinki, Finland) with standard exposure settings used in clinical practice (60 kV, 2 mA, and maximum FOV). An automated calculator algorithm was developed in MATLAB platform. Two parameters associated with panoramic image distortion such as balls diameter and distance between middle and tenth balls were measured. These automated measurements were compared with manual measurement using the Planmeca Romexis and ImageJ software.

RESULTS

The findings showed smaller deviation in distance difference measurements by proposed automated calculator (ranged 3.83 mm) as compared to manual measurements (ranged 5.00 for Romexis and 5.12 mm for ImageJ software). There was a significant difference (p < 0.05) on the mean measured ball diameter between automated and manual measurement. For ball diameter measurement, there is a moderate positive correlation between automated measurement with the manual measurements (r = 0.6024 and r = 0.6358 for Romexis and ImageJ, respectively). However, there is a negative correlation between automated measurement for the distance difference with manual methods (r = -0.3484 and r = -0.3494 for Romexis and ImageJ, respectively). There was a good approximation between automated and ImageJ measurement of ball diameter in comparison to reference value.

CONCLUSION

In conclusion, the proposed automated calculator provides faster method with an accurate and acceptable results for daily-basis image quality test in dental panoramic mode of a Dental CBCT imaging system in comparison to current manual method.

IMPLICATIONS FOR PRACTICE

An automated calculator is recommended for image distortion analysis on phantom images in routine image quality assessment for dental panoramic mode of Dental CBCT imaging system that may involve analysis of large image datasets. It offers improvement in routine image quality practice in term of time and accuracy.

Super-Resolution of Dental Panoramic Radiographs Using Deep Learning: A Pilot Study

Using super-resolution (SR) algorithms, an image with a low resolution can be converted into a high-quality image. Our objective was to compare deep learning-based SR models to a conventional approach for improving the resolution of dental panoramic radiographs. A total of 888 dental panoramic radiographs were obtained. Our study involved five state-of-the-art deep learning-based SR approaches, including SR convolutional neural networks (SRCNN), SR generative adversarial network (SRGAN), U-Net, Swin for image restoration (SwinIr), and local texture estimator (LTE). Their results were compared with one another and with conventional bicubic interpolation. The performance of each model was evaluated using the metrics of mean squared error (MSE), peak signal-to-noise ratio (PNSR), structural similarity index (SSIM), and mean opinion score by four experts (MOS). Among all the models evaluated, the LTE model presented the highest performance, with MSE, SSIM, PSNR, and MOS results of 7.42 ± 0.44, 39.74 ± 0.17, 0.919 ± 0.003, and 3.59 ± 0.54, respectively. Additionally, compared with low-resolution images, the output of all the used approaches showed significant improvements in MOS evaluation. A significant enhancement in the quality of panoramic radiographs can be achieved by SR. The LTE model outperformed the other models.

Extraoral bite-wing radiographs: A universally accepted paradox

BACKGROUND

The development of specialized panoramic radiograph machine software has spawned the introduction of an innovative and promising dental radiographic examination type: extraoral bite-wings. But does this unconventional type of imaging belong in the bite-wing family? Is there any relationship at all to the conventional bite-wing radiograph?

OBJECTIVES

The purpose of this article is not to make a case for the diagnostic effectiveness of one system over the other; this is best left to further clinical evaluation. Instead, the authors intend to provide an outline of a few key and distinguishing elements of the intraoral bite-wing radiographic examination followed by those of the extraoral panoramic substitute and draw attention to the importance of reimagining the increasingly universal naming convention of this novel radiographic examination, the paradoxical "extraoral bite-wing radiograph", based on the fundamental principles of each of these imaging systems.

PRACTICAL IMPLICATIONS

The accuracy of clinical and technical terminology in oral radiography is of paramount importance to both the profession and patients, especially when considering emerging technologies.