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Purpose This study was performed to investigate the effect of exposure parameters on image quality obtained using a cone-beam computed tomography (CBCT) scanner and the relationship between physical factors and clinical image quality depending on the diagnostic task. Materials and methods CBCT images of a SedentexCT IQ phantom and a real skull phantom were obtained under different combinations of tube voltage and tube current (Alphard 3030 CBCT scanner, 78-90 kVp and 2-8 mA). The images obtained using a SedentexCT IQ phantom were analyzed technically, and the physical factors of image noise, contrast resolution, spatial resolution, and metal artifacts were measured. The images obtained using a real skull phantom were evaluated for each diagnostic task by 6 oral and maxillofacial radiologists, and each setting was classified as acceptable or unacceptable based on those evaluations. A statistical analysis of the relationships of exposure parameters and physical factors with observer scores was conducted. Results For periapical diagnosis and implant planning, the tube current of the acceptable images was significantly higher than that of the unacceptable images. Image noise, the contrast-to-noise ratio (CNR), the line pair chart on the Z axis, and modulation transfer function (MTF) values showed statistically significant differences between the acceptable and unacceptable image groups. The cut-off values obtained using receiver operating characteristic curves for CNR and MTF 10 were useful for determining acceptability. Conclusion Tube current had a major influence on clinical image quality. CNR and MTF 10 were useful physical factors that showed significantly associations with clinical image quality.

Purpose This study investigated the relationship between pain and internal derangement in temporomandibular disorder (TMD) patients using magnetic resonance imaging (MRI). Materials and Methods This study analyzed 356 TMD patients (712 temporomandibular joints [TMJs]). The inclusion criteria were the presence of spontaneous or provoked pain on one or both TMJs and having undergone MRI. The patients with provoked pain were divided into 3 groups: pain on palpation, pain on mouth opening, and pain on mastication. MRI was performed using a 1.5-T scanner. T1- and T2-weighted parasagittal and paracoronal images were obtained. According to the findings on the T1-weighted images, another 3 groups were created based on internal derangement: normal, disc displacement with reduction, and disc displacement without reduction. The MRI findings were independently interpreted by 2 experienced oral and maxillofacial radiologists at 2 different times. Statistical analysis was performed by the chi-square test using SPSS (version 12.0; SPSS Inc., Chicago, IL, USA). Results Provoked pain on mouth opening was found to be correlated with internal derangement in TMD patients (P.05). Conclusion These results suggest that internal derangement was a significant predictor of provoked pain on mouth opening.

Purpose: This study was performed to find the relationship between pain and joint effusion using magnetic resonance imaging (MRI) in temporomandibular disorder (TMD) patients. Materials and Methods: The study subjects included 232 TMD patients. The inclusion criteria in this study were the presence of spontaneous pain or provoked pain on one or both temporomandibular joints (TMJs). The provoked pain was divided into three groups: pain on palpation (G1), pain on mouth opening (G2), and pain on mastication (G3). MRI examinations were performed using a 1.5-T MRI scanner. T1- and T2-weighted images with para-sagittal and para-coronal images were obtained. According to the T2-weighted image findings, the cases of effusions were divided into four groups: normal, mild (E1), moderate (E2), and marked effusion (E3). A statistical analysis was carried out using the χ 2 test with SPSS (version 12.0, SPSS Inc., Chicago, IL, USA). Results: Spontaneous pain, provoked pain, and both spontaneous and provoked pain were significantly related to joint effusion in TMD patients (p⁄0.05). However, among the various types of provoked pain, pain on palpation of the masticatory muscles and TMJ (G1) was not related to joint effusion in TMD patients (p¤0.05). Conclusion: Spontaneous pain was related to the MRI findings of joint effusion; however, among the various types of provoked pain, pain on palpation of the masticatory muscles and TMJ was not related to the MRI findings of joint effusion. These results suggest that joint effusion has a significant influence on the prediction of TMJ pain. (Imaging Sci Dent 2014; 44: 293-9)

Gardner syndrome is known as a variant of familial adenomatous polyposis. This syndrome is characterized by multiple intestinal polyposes, osteomas, and epidermoid cysts. In addition, dental abnormalities include an increased frequency of multiple odontomas, as well as supernumerary and impacted teeth. The authors report the case of a 7-year-old male patient with Gardner syndrome. Radiographic findings revealed multiple osteomas in both sides of the maxilla, multiple diffuse enostoses in both jaws, and a complex odontoma in the left mandibular body. Two years later, multiple epidermoid cysts on the scalp were found. Since this patient was suspected to have Gardner syndrome, the authors recommended gastrointestinal endoscopy to check for intestinal polyposis. Gastrointestinal endoscopic examination revealed multiple polyposes in the upper gastrointestinal tract and fundus of the stomach. As a result, the final diagnosis was Gardner syndrome.

The desmoplastic variant of ameloblastoma is a rare form of ameloblastoma characterized by unique radiographic and histologic features. A 46-year-old female was referred to our hospital, complaining of swelling in the left upper lip area. Radiographic findings revealed an ill-defined multilocular lesion with a large cystic lesion and thick sclerotic trabeculae on the left anterior maxilla. After the patient underwent partial osteotomy, histologic analysis revealed a desmoplastic ameloblastoma with no evidence of a hybrid lesion or cyst formation. The radiographic findings in the present case were different from those described in previous case reports. These findings are of special importance due to the unfamiliar radiographic and histologic features of this lesion.

Purpose: This study was performed to evaluate the relationship between anterior disc displacement and effusion in temporomandibular disorder (TMD) patients using magnetic resonance imaging (MRI). Materials and Methods: The study subjects included 253 TMD patients. MRI examinations were performed using a 1.5 T MRI scanner. T1- and T2-weighted images with para-sagittal and para-coronal images were obtained. According to the MRI findings, temporomandibular joint (TMJ) disc positions were divided into 3 subgroups: normal, anterior disc displacement with reduction (DWR), and anterior disc displacement without reduction (DWOR). The cases of effusion were divided into 4 groups: normal, mild (E1), moderate (E2), and marked effusion (E3). Statistical analysis was made by the Fisher’s exact test using SPSS (version 12.0, SPSS Inc., Chicago, IL, USA). Results: The subjects consisted of 62 males and 191 females with a mean age of 28.5 years. Of the 253 patients, T1and T2-weighted images revealed 34 (13.4%) normal, DWR in 103 (40.7%), and DWOR in 116 (45.9%) on the right side and 37 (14.6%) normal, DWR in 94 (37.2%), and DWOR in 122 (48.2%) joints on the left side. Also, T2-images revealed 82 (32.4%) normal, 78 (30.8%) E1, 51 (20.2%) E2, and 42 (16.6%) E3 joints on the right side and 79 (31.2%) normal, 85 (33.6%) E1, 57 (22.5%) E2, and 32 (12.7%) E3 on the left side. There was no difference between the right and left side. Conclusion: Anterior disc displacement was not related to the MRI findings of effusion in TMD patients (P¤0.05). (Imaging Sci Dent 2013; 43 : 245-51)

Purpose: This study was performed to evaluate the trabecular pattern on panoramic radiographs to predict agerelated osteoporosis in postmenopausal women. Materials and Methods: Thirty-one postmenopausal osteoporotic women and 25 postmenopausal healthy women between the ages of 50 and 88 were enrolled in this study. The bone mineral density (BMD) of the lumbar vertebrae and femur were calculated using dual-energy X-ray absorptiometry (DXA), and panoramic radiographs were obtained. Fractal dimension (FD) was measured using the box counting method from 560 regions of interest (51×51 pixels) in 6 sites on the panoramic radiographs. The relationships between age and BMD and between FD and BMD were assessed, and the intraobserver agreement was determined. Results: There was a significant difference in the FD values between the osteoporotic and normal groups (p⁄0.05). There was a significant difference in the FD values at three sites in the jaws (p⁄0.05). Age was significantly correlated with the BMD measurements, with an odds ratio of 1.25. However, the FD values were not significantly correlated with the BMD measurements, with an odds ratio of 0.000. The intraobserver agreement showed relatively higher correlation coefficients at the upper premolar, lower premolar, and lower anterior regions than the other sites. Conclusion: Age was an important risk factor for predicting the presence of osteoporosis in postmenopausal women. The lower premolar region was the most appropriate site for evaluating the FD value on panoramic radiographs. However, further investigation might be needed to predict osteoporosis using an FD value on panoramic radiographs. (Imaging Sci Dent 2012; 42 : 231-5)