Traumatic bone cyst (TBC) occurs preferentially on the mandibular symphysis and body, but rarely on the mandibular condyle. When TBC occurs in the condylar area, it can usually be related with or misdiagnosed as a temporomandibular joint disorder. A 15-year-old female patient visited the Temporomandibular Joint Clinic with a 5-year history of pain and noise localized in the left temporomandibular joint. On imaging, a well demarked oval-shaped radiolucent lesion was observed on the left condyle head. The patient underwent cyst enucleation and repositioning of the bony window on the lateral cortex of the affected condyle head under the impression of subchondral cyst or TBC; however, no cystic membrane was found. The bone defect resolved and showed no recurrence on the serial radiographic postoperative follow-up for 43 months after surgery.
Adolescent ; Bone Cysts* ; Female ; Follow-Up Studies* ; Head ; Humans ; Mandibular Condyle* ; Membranes ; Noise ; Recurrence ; Temporomandibular Joint ; Temporomandibular Joint Disorders

We report a case of large radicular cyst progression related to endodontic origin to emphasize proper intervention and follow-up for endodontic pathosis. A 25 yr old man presented with an endodontically treated molar with radiolucency. He denied any intervention because of a lack of discomfort. Five years later, the patient returned. The previous periapical lesion had drastically enlarged and involved two adjacent teeth. Cystic lesion removal and apicoectomy were performed on the tooth. Histopathological analysis revealed that the lesion was an inflammatory radicular cyst. The patient did not report any discomfort except for moderate swelling 3 days after the surgical procedure. Although the patient had been asymptomatic, close follow-ups are critical to determine if any periapical lesions persist after root canal treatment.
Apicoectomy ; Dental Pulp Cavity ; Follow-Up Studies ; Humans ; Molar ; Radicular Cyst* ; Tooth

No abstract available.
Humans ; Infarction* ; Ischemic Attack, Transient* ; Lateral Medullary Syndrome ; Trigeminal Neuralgia*

PURPOSE: To evaluate CT findings of tuberculous pneumonia mainly presenting as parenchymal consolidation. MATERIALS & METHODS: CT scans of twenty patients with tuberculous pneumonia were retrospectively reviewed. Analyses included the location, extent, and homogeneity of consolidation, presence of volume loss of involved lung and air-bronchogram, associated lesions suggesting previous tuberculous infection and evidence of bronchogenic spread. RESULTS: The location of consolidation revealed relatively even distribution without any specific predilection site. The areas of consolidation were irregular in margin (95%), inhomogeneous in attenuation (75%) including focal areas of low attenuation and multiple cavities within it. Volume loss (70%) of the involved lobe was associated. There were lesions suggesting previous tuberculous infection (95%) in the surrounding area and evidences of bronchogenic spread (100%) such as poorly-defined nodules and Iobular consolidations in the remote site from main consolidation. CONCLUSION: In tuberculous pneumonia, the areas of consolidation are irregular in margin and inhomogeneous in attenuation on CT scan. The evidences of bronchogenic spread and lesions suggesting previous tuberculous infection are almost always associated in the surrounding or remote site from main consolidation.
Humans ; Lung ; Pneumonia* ; Retrospective Studies ; Tomography, X-Ray Computed

PURPOSE: The purpose of this study was to report the reproducibility of intra-observer and inter-observer consistency of cephalometric measurements using three-dimensional (3D) computed tomography (CT), and the degree of difference of the cephalometric measurements. MATERIALS AND METHODS: CT images of 16 adult patients with normal class I occlusion were sent to personal computer and reconstructed into 3D images using V-Works 3.5 TM (Cybermed Inc., Seoul, Korea). With the internal program of V-Works 3.5 TM, 12 landmarks on regular cephalograms were transformed into 21 analytic categories and measured by 2 observers and in addition, one of the observers repeated their measurements. Intra-observer difference was calculated using paired t-test, and inter-observer by two sample test. RESULTS: There were significant differences in the intra-observer measurements (p< 0.05) in four of the categories which included ANS-Me, ANS-PNS, Cdl-Go (Lt), GoL-GoR, but with the exception of Cdl-Go (Lt), ZmL-ZmR, Zyo-Zyo, the average differences were within 2 mm of each other. The inter-observer observations also showed significant differences in the measurements of the ZmL-ZmR and Zyo-Zyo categories (p< 0.05). With the exception of the Cdl-Me (Rt), ZmL-ZmR, Zyo-Zyo categories, the average differences between the two observers were within 2 mm, but the ZmL-ZmR and Zyo-Zyo values differed greatly with values of 8.10 and 19.8 mm respectively. CONCLUSION: In general, 3D CT images showed greater accuracy and reproducibility, with the exception of suture areas such as Zm and Zyo, than regular cephalograms in orthodontic measurements, showing differences of less than 2 mm, therefore 3D CT images can be useful in cephalometric measurements and treatment planning.
Adult ; Cephalometry ; Humans ; Microcomputers* ; Reproducibility of Results ; Seoul ; Sutures ; Tomography, X-Ray Computed

Purpose: This study aimed to compare the therapeutic effects of corticosteroid irrigations and normal saline irrigations in the early inflammatory state of the salivary gland. Materials and Methods: Adult male Wistar rats were divided into experimental (n=6) and control (n=3) groups. Inflammation was induced in the experimental subjects on both sides of the submandibular gland with ligation. After 14 days, both sides of the glands were de-ligated and retroductal irrigation using saline (n=3) and a corticosteroid (n=3) was performed on the left sides only. The controls (n=3) were used to normalize the gland state for the effects of diet and aging. Magnetic resonance imaging was performed to confirm inflammation and post-irrigation gland recovery by measuring relative signal intensity (SI). The glands were excised for histological examination. Results: All experimental animals showed inflamed glands with increased SI and subsequent recovery of the gland with decreased SI to varying degrees. The SI of the controls showed no significant changes during the overall period. The mean SI change of the irrigated gland was higher than that of the non-irrigated side, without a significant difference. The corticosteroid-irrigated glands showed a greater change in SI than that of the saline-irrigated glands. Histology revealed that inflammation was not observed in most of the irrigated glands, while mild to moderate quantities inflammatory cells were found in non-irrigated glands. Conclusion Corticosteroid irrigation mitigated the early stages of salivary gland inflammation more effectively than normal saline.

Purpose: This study aimed to evaluate the performance of transfer learning in a deep convolutional neural network for classifying implant fixtures. Materials and Methods: Periapical radiographs of implant fixtures obtained using the Superline (Dentium Co. Ltd., Seoul, Korea), TS III (Osstem Implant Co. Ltd., Seoul, Korea), and Bone Level Implant (Institut Straumann AG, Basel, Switzerland) systems were selected from patients who underwent dental implant treatment. All 355 implant fixtures comprised the total dataset and were annotated with the name of the system. The total dataset was split into a training dataset and a test dataset at a ratio of 8 to 2, respectively. YOLOv3 (You Only Look Once version 3, available at https://pjreddie.com/darknet/yolo/), a deep convolutional neural network that has been pretrained with a large image dataset of objects, was used to train the model to classify fixtures in periapical images, in a process called transfer learning. This network was trained with the training dataset for 100, 200, and 300 epochs. Using the test dataset, the performance of the network was evaluated in terms of sensitivity, specificity, and accuracy. Results: When YOLOv3 was trained for 200 epochs, the sensitivity, specificity, accuracy, and confidence score were the highest for all systems, with overall results of 94.4%, 97.9%, 96.7%, and 0.75, respectively. The network showed the best performance in classifying Bone Level Implant fixtures, with 100.0% sensitivity, specificity, and accuracy. Conclusion Through transfer learning, high performance could be achieved with YOLOv3, even using a small amount of data.

Purpose: This study was to investigate the types of imaging modalities, analytical methods for age estimation, and the age of the subjects in research on age estimation using dental radiography through a scoping review, and to investigate the overall trends in age estimation studies. Materials and Methods: A scoping review was designed according to the Arksey and O’Malley guidelines and the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement. Three electronic databases were used as search sources (Medline, Embase, and Cochrane Library). Studies were classified according to the three main components of the research question. “What are the imaging modalities, analytical methods, and target age in dental imaging-based age estimation studies?”Result: The final 198 studies were selected by two reviewers. The most common imaging modality used in studies was panoramic radiography (69.7%), and studies using cone-beam computed tomography have increased over time. Analytical methods for age estimation were 62.6% in studies based on tooth development and 26.3% in studies using pulp/tooth ratio. The subject age was 27.8% for children and 27.3% for adults. Studies conducted in all age groups comprised the smallest category (5.2%). Conclusion Panoramic radiography has been the most used types of imaging modalities for age estimation, and the most common analytical method was analysis of tooth development. Most studies targeted specific ages, and very few involved all age groups. Dental age estimation studies should be carried out with appropriate consideration of the imaging modality that is analyzed, the methods that are used, and the age that is targeted.

Purpose: This study proposed a generative adversarial network (GAN) model for T2-weighted image (WI) synthesis from proton density (PD)-WI in a temporomandibular joint (TMJ) magnetic resonance imaging (MRI) protocol. Materials and Methods: From January to November 2019, MRI scans for TMJ were reviewed and 308 imaging sets were collected. For training, 277 pairs of PD- and T2-WI sagittal TMJ images were used. Transfer learning of the pix2pix GAN model was utilized to generate T2-WI from PD-WI. Model performance was evaluated with the structural similarity index map (SSIM) and peak signal-to-noise ratio (PSNR) indices for 31 predicted T2-WI (pT2). The disc position was clinically diagnosed as anterior disc displacement with or without reduction, and joint effusion as present or absent. The true T2-WI-based diagnosis was regarded as the gold standard, to which pT2-based diagnoses were compared using Cohen’s ĸ coefficient. Results: The mean SSIM and PSNR values were 0.4781(±0.0522) and 21.30(±1.51) dB, respectively. The pT2 protocol showed almost perfect agreement (ĸ=0.81) with the gold standard for disc position. The number of discordant cases was higher for normal disc position (17%) than for anterior displacement with reduction (2%) or without reduction (10%). The effusion diagnosis also showed almost perfect agreement (ĸ=0.88), with higher concordance for the presence (85%) than for the absence (77%) of effusion. Conclusion The application of pT2 images for a TMJ MRI protocol useful for diagnosis, although the image quality of pT2 was not fully satisfactory. Further research is expected to enhance pT2 quality.

Purpose: This study aimed to investigate the computed tomography and magnetic resonance imaging features of giant cell tumors in the temporomandibular joint region to facilitate accurate diagnoses. Materials and Methods: From October 2007 to June 2020, 6 patients (2 men and 4 women) at Yonsei University Dental Hospital had histopathologically proven giant cell tumors in the temporomandibular joint. Their computed tomography and magnetic resonance imaging findings were reviewed retrospectively, and the cases were classified into 3 types based on the tumor center and growth pattern observed on the radiologic findings. Results: The age of the 6 patients ranged from 25 to 53 years. Trismus was found in 5 of the 6 cases. One case recurred. The mean size of the tumors, defined based on their greatest diameter, was 32 mm (range, 15–41 mm). The characteristic features of all cases were a heterogeneously-enhancing tumorous mass with a lobulated margin on computed tomographic images and internal multiplicity of signal intensity on T2-weighted magnetic resonance images. According to the site of origin, 3 tumors were bone-centered, 2 were soft tissue-centered, and 1 was peri-articular. Conclusion Computed tomography and magnetic resonance imaging yielded a tripartite classification of giant cell tumors of the temporomandibular joint according to their location on imaging. This study could help clinicians in the differential diagnosis of giant cell tumors and assist in proper treatment planning for tumorous diseases of the temporomandibular joint.