Oral Radiology最新文献

Objectives: This study aimed to evaluate the detrimental effects of single unilaterally impacted mesiodens on the root development of adjacent maxillary central incisors and to explore the key influencing factors.

Methods: A total of 552 patients aged 5-12 years with single unilaterally impacted mesiodens were included in the study. The maxillary central incisor with greater overlap with the mesiodens in the coronal view was identified as the affected tooth, while the contralateral central incisor served as the control one. Cone-beam computed tomography (CBCT) data for these patients were retrospectively analyzed to compare the root lengths and root formation stages of the maxillary central incisors on both sides. Multivariate logistic regression and generalized linear models were used to investigate the critical 3-dimensional (3D) characteristics that influence the root development of adjacent maxillary central incisors.

Results: Maxillary central incisors on the affected side exhibited significantly shorter root lengths and less-advanced root formation stages compared to those on the control side. Impacted mesiodens with tuberculate or germ morphology, normal or undefined orientation, and a position superior to dental cervix of contralateral central incisor were associated with higher risk of impairing root development of adjacent central incisors.

Conclusions: Impacted mesiodens can impair the root development of adjacent central incisors. Early removal of high-risk mesiodens is essential for safeguarding the future development of adjacent maxillary central incisors.

Objective: To assess whether the use of different types of facial sunscreen influences the quality of radiographic images and the absorbed radiation dose during radiographic acquisitions.

Methods: In this in vitro study, two types of facial sunscreens (Bioderma^®), both with a sun protection factor of 50, were tested: one organic and one inorganic. A polystyrene plate was used, containing a thermoluminescent dosimeter and a photostimulable phosphor plate for the radiographs. The sunscreen was applied to the plate, and five radiographs were taken for each group: control (without sunscreen), organic sunscreen, and inorganic sunscreen. Image quality was assessed by noise, brightness, and uniformity, and the radiation dose was measured in milligrays. The results were compared using one-way analysis of variance with Tukey post-hoc test (α = 5%).

Results: Inorganic sunscreen produced images with higher brightness and lower uniformity, with no significant differences in noise. Additionally, this group showed a lower radiation dose (0.50 mGy) compared to the control group (0.60 mGy) and the organic sunscreen (0.58 mGy) (p < 0.05).

Conclusion: The inorganic sunscreen altered image quality by increasing brightness and decreasing uniformity, while also reducing the absorbed radiation dose.

Aim: Cone-beam computed tomography (CBCT) imaging plays a crucial role in dentistry, with automatic prediction of anatomical structures on CBCT images potentially enhancing diagnostic and planning procedures. This study aims to predict anatomical structures automatically on CBCT images using a deep learning algorithm.

Materials and methods: CBCT images from 70 patients were analyzed. Anatomical structures were annotated using a regional segmentation tool within an annotation software by two dentomaxillofacial radiologists. Each volumetric dataset comprised 405 slices, with relevant anatomical structures marked in each slice. Seventy DICOM images were converted to Nifti format, with seven reserved for testing and the remaining sixty-three used for training. The training utilized nnUNetv2 with an initial learning rate of 0.01, decreasing by 0.00001 at each epoch, and was conducted for 1000 epochs. Statistical analysis included accuracy, Dice score, precision, and recall results.

Results: The segmentation model achieved an accuracy of 0.99 for nasal fossa, maxillary sinus, nasopalatine canal, mandibular canal, foramen mentale, and foramen mandible, with corresponding Dice scores of 0.85, 0.98, 0.79, 0.73, 0.78, and 0.74, respectively. Precision values ranged from 0.73 to 0.98. Maxillary sinus segmentation exhibited the highest performance, while mandibular canal segmentation showed the lowest performance.

Conclusion: The results demonstrate high accuracy and precision across most structures, with varying Dice scores indicating the consistency of segmentation. Overall, our segmentation model exhibits robust performance in delineating anatomical features in CBCT images, promising potential applications in dental diagnostics and treatment planning.

Background: Motion artifacts decrease the quality of cone-beam computed tomography (CBCT) images. Knowledge about the efficacy and accuracy of motion artifact correction software programs can be beneficial.

Objectives: This study aimed to assess the effect of motion artifacts and their correction software on quality and interpretability of CBCT images.

Materials and methods: In this ex-vivo experimental study, a dry human mandible was moved mesiodistally and anteroposteriorly by 1 and 3 mm for 1 s by a robot during CBCT scanning. The images were reconstructed by Romexis software, and three observers evaluated the quality and interpretability of images with and without the application of Planmeca CALM™ software for artifact correction. The effects of distance and direction of movement, landmark location, scanner resolution, and application of CALM software on quantitative and qualitative interpretability, measurability, and sharpness of images were analyzed.

Results: A high percentage of agreement existed among the three observers in all variables (P < 0.05). Landmark location and direction of movement had no significant correlation with qualitative interpretability, measurability, and sharpness of images (P > 0.05). Distance of movement had a significant effect on qualitative interpretability and sharpness (P < 0.05) but not measurability (P > 0.05) of images. Application of CALM had no significant correlation with qualitative interpretability, measurability, or sharpness (P > 0.05). Resolution of scanner had a significant effect on qualitative interpretability and sharpness but not measurability (P > 0.05).

Conclusions: Distance of movement ≤ 1 mm and application of CALM significantly improved the quantitative interpretability of CBCT images.

Objectives: In this bibliometric analysis, various parameters such as leading journals, universities, countries, authors and keywords related to the use of ultrasonography (USG) in dentistry were analysed with the help of bibliometric mapping, aiming to help researchers evaluate scientific results on this subject and design future research.

Methods: In this bibliometric analysis, using the Web of Science (WoS) database various factors such as publication date, number of citations, publication language, journals published, countries, and keywords of articles covering research on the use of USG in dentistry between 1981 and 2024 were examined.

Results: It has been determined that the number of articles and citations regarding the use of USG in dentistry is increasing day by day. While 6 articles were published in this field in 2000, 94 publications were made in 2023. While 25 citations were made in 2000 for articles published on the use of USG in dentistry, this number reached 2334 in 2023. The country with the most publications in this field was the USA, and the journal with the most publications was Dentomaxillofacial Radiology.

Conclusion: The findings of this current analysis may help researchers categorize scientific conclusions regarding the use of USG in dentistry and thus select issues to examine when designing future research.

Objective: To summarize the ultrasonography (US) and magnetic resonance imaging (MRI) findings of lymphoepithelial cysts (LECs) and dermoid cysts (DCs) and to discuss the hyperinternal echo in LECs based on histopathological findings.

Methods: Patients who underwent US and MRI before resection and whose lesions were pathologically diagnosed as LECs or DCs were included (January 2010 to December 2023). Internal echo, convective flow, and Doppler signals were evaluated on US, while on MRI, we measured the apparent diffusion coefficient (ADC).

Results: Surprisingly, all lesions (4 LECs and 7 DCs) had hyperinternal echoes. Convective flow and Doppler signals were observed in 2 of the 4 cases of LEC, and the ADC was high in these cases (2.4 × 10^-3 and 2.0 × 10^-3 mm²/s). In the two cases where they were not, the ADC was low (1.4 × 10^-3 and 0.81 × 10^-3 mm²/s). Various cells, such as lymphocyte cells, foam cells, erythroid cells, and keratin, have been found in the cystic cavity, which are thought to be the cause of hyperecho. Considering the ADC, the presence or absence of convection and Doppler signals is thought to reflect the ease of movement of the contents. In the DCs, neither internal convection nor obvious Doppler signals were observed. ADCs were quite low for cysts, which was a characteristic finding (1.1 ± 0.13^-3 mm²/s).

Conclusion: It is well known that DCs appear hyperechoic on US owing to the presence of keratin; however, it is necessary to recognize that some LECs are depicted as hyperechoic masses and have convective flow and Doppler signals depending on the content.

Objectives: Osteoma is a rare, benign bone-forming tumor. Clinicians may be unfamiliar with this lesion. This study aimed to evaluate the clinical and radiographic features of osteomas to aid accurate diagnosis.

Methods: Osteomas diagnosed in the oral and maxillofacial region at two dental schools between January 2012 and October 2023 were analyzed. Clinical, radiographic features, and histopathologic variants were evaluated.

Results: Twelve patients (8 females, 4 males) with a total of 13 osteomas were identified. Four were central (1 mandibular, 2 maxillary, 1 glenoid fossa) and 9 were periosteal (7 mandibular, 1 maxillary, 1 maxillary sinus floor). Mandibular lesions included 3 in the posterior region, 1 anterior involving the genial tubercle and body, 2 at the angle, 1 at the ramus, and 1 at the condyle. Two maxillary lesions were in the posterior region, and 1 extended from the canine to the molar region with impacted teeth. Central osteomas typically appeared as irregular, dense radiopaque masses with blending borders, whereas periosteal osteomas presented as round/oval or irregular radiopaque masses with well-defined borders. Central osteoma may be difficult to distinguish from fibro-osseous lesions, whereas the diagnosis of periosteal osteoma is often straightforward. Osteomas in the maxilla associated with impacted teeth, the glenoid fossa, and the genial tubercle each represent the fourth reported cases in the literature.

Conclusions: Osteomas in the oral and maxillofacial region are rare and may present in uncommon locations. These findings contribute to a broader understanding of osteomas and may assist healthcare professionals in making accurate diagnoses.

Objectives: This study aimed to identify the most effective diagnostic assistance system for assessing the relationship between mandibular third molars (M3M) and mandibular canals (MC) using panoramic radiographs.

Methods: In total, 2,103 M3M were included from patients in whom the M3M and MC overlapped on panoramic radiographs. All M3M were classified into high-risk and low-risk groups based on the degree of contact with the MC observed on computed tomography. The contact classification was evaluated using four machine learning models (Prediction One software, AdaBoost, XGBoost, and random forest), three convolutional neural networks (CNNs) (EfficientNet-B0, ResNet18, and Inception v3), and three human observers (two radiologists and one oral surgery resident). Receiver operating characteristic curves were plotted; the area under the curve (AUC), accuracy, sensitivity, and specificity were calculated. Factors contributing to prediction of high-risk cases by machine learning models were identified.

Results: Machine learning models demonstrated AUC values ranging from 0.84 to 0.88, with accuracy ranging from 0.81 to 0.88 and sensitivity of 0.80, indicating consistently strong performance. Among the CNNs, ResNet18 achieved the best performance, with an AUC of 0.83. The human observers exhibited AUC values between 0.67 and 0.80. Three factors were identified as contributing to prediction of high-risk cases by machine learning models: increased root radiolucency, diversion of the MC, and narrowing of the MC.

Conclusion: Machine learning models demonstrated strong performance in predicting the three-dimensional relationship between the M3M and MC.

Objectives: The aim of this study was to compare the use of panoramic radiography (PAN) and panoramic reconstructions obtained from cone beam computed tomography (CBCT) for the evaluation of trabecular bone structure using fractal dimension (FD).

Methods: This cross-sectional study evaluated PAN and CBCT images of 20 patients. In each tomographic volume, panoramic reconstructions were obtained with the following thicknesses: 160 µm; 480 µm; 800 µm; 1.1 mm; 2.1 mm; 3.0 mm; 4.0 mm; 5.0 mm; 10.1 mm; 14.9 mm; 20.0 mm; 29.9 mm; 40.2 mm, and 50.1 mm. For each image acquired, the FD value of the regions of interest (ROI) was calculated by the White and Rudolph technique. Six ROIs of 40 × 40 pixels were manually selected 2 mm superior, 2 mm anterior and 2 mm inferior to the mental foramen.

Results: The results were statistically significant for the FD values obtained from the different exams evaluated (p < 0.001) and for the ROIs analyzed (p = 0.021). However, when the type of imaging exam and the ROIs were compared, no significant difference was observed between the groups (p = 0.993). Regarding the different panoramic reconstruction thicknesses, a difference was observed between the thinner reconstructions (160 µm and 480 µm) and the thicker reconstructions (29.9 mm; 40.2 mm and 50.1 mm) (p < 0.001).

Conclusions: There are differences between the FD values obtained from PAN and panoramic reconstructions from CBCT, and differences between ROIs within the same imaging exam.

Objectives: Sjögren's syndrome causes dryness of the eyes and mouth due to destruction of glandular tissue. Single-photon emission computed tomography/computed tomography (SPECT/CT) is used to evaluate salivary gland function. This study aimed to quantitatively evaluate the stage of Sjögren's syndrome using SPECT/CT maximum standardized uptake value (SUVmax) by comparing the SUVmax with the Saxon test, magnetic resonance (MR) sialography stage, and histopathological grade.

Methods: This study was conducted in 29 patients with Sjögren's syndrome who underwent the Saxon test, MR sialography, SPECT/CT, and histopathological examination. We compared the SPECT/CT SUVmax with the Saxon test, MR sialography stage, and histopathological grade to determine the stage of Sjögren's syndrome. We then calculated the cutoff value of SUVmax at pre-stimulation for the parotid glands in the early and late stages of Sjögren's syndrome.

Results: The SUVmax for > 2 g per 2 min by the Saxon test was higher than that for ≤ 2 g per 2 min. The SUVmax for MR sialography stages 0-1 was higher than that for stages 2-4. The SUVmax for histopathological grades 0-2 was higher than that for grades 3-4. The cutoff value for early and late Sjögren's syndrome was 20.55 (sensitivity, 0.85; specificity, 0.67).

Conclusions: SPECT/CT is a highly suitable modality for quantitatively evaluating the stage of Sjögren's syndrome. Especially, the pre-stimulation SUVmax of the parotid glands serves as a valuable indicator for assessing Sjögren's syndrome stage and predicting prognosis.