• Imaging Science in Dentistry
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• v.34 no.3
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• pp.171-174
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• 2004

The present study reports a case of developmental salivary gland defect. On panoramic examination, large radiolucent lesion surrounded by a sclerotic wall was noted in the right posterior mandible. On CT examination, large lingual bone concavity with extra-osseous course of the inferior alveolar nerve bundle was detected. In atypical cases, it is suggested that confirmatory imaging using CT or MRI should be taken.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.24 no.2
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• pp.317-326
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• 1994

Panoramic radiographs of a dry skull were used to evaluate the accuracy of four panoramic dental X-ray systems in determining tooth angulations in the buccal segments. The four machines evaluated were the Philips Oralix Pan DC, the GE panelipse, the SS White panorex 1, and the SS White Panorex 2. Panoramic radiographs were taken at six different patient positions for each machine to evaluate the effects of patient positioning on determining tooth angulations in the buccal segments. All of the machines studied showed a significant correlation between the mean radiographic estimates and the actual measurements regardless of positioning(p<0.05). With correct placement of the skull, the results were analyzed for an error tolerance of +/-3/sup 0/ between the actual measurements and the radiographic estimates for tooth angulation. The SS White Panorex 1 was accurate 74% of the time, the GE Panelipse was accurate 67% of the time, the Philips Oralix Pan DC and the SS White Panorex 2 were accurate 64% of the time. When an error tolerance of +/-5/sup 0/ was permitted, the accuracy was 89% for the SS White Panorex 1 and the GE Panelipse, 85% for the Philips Oralix Pan DC, and 81% for the SS White Panorex 2.

• Imaging Science in Dentistry
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• v.35 no.3
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• pp.157-165
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• 2005

Purpose : To find out the proper compression ratios without degrading image quality and affecting lesion detectability on diagnostic images used in dentistry compressed with JPEG 2000 algorithm. Materials and Methods : Sixty Digora periapical images, sixty panoramic computed radiographic (CR) images, sixty computed tomographic (CT) images, and sixty magnetic resonance (MR) images were compressed into JPEG 2000 with ratios of 10 levels from 5:1 to 50:1. To evaluate the lesion detectability, the images were graded with 5 levels (1 : definitely absent; 2: probably absent; 3: equivocal; 4: probably present; 5: definitely present), and then receiver operating characteristic analysis was performed using the original image as a gold standard. Also to evaluate subjectively the image quality, the images were graded with 5 levels (1 definitely unacceptable; 2: probably unacceptable; 3: equivocal, 4: probably acceptable; 5· definitely acceptable), and then paired t-test was performed. Results : In Digora, CR panoramic and CT images, compressed images up to ratios of 15 : 1 showed nearly the same lesion detectability as original images, and in MR images, compressed images did up to ratios of 25 : 1. In Digora and CR panoramic Images, compressed images up to ratios of 5 : 1 showed little difference between the original and reconstructed images in subjective assessment of image quality In CT images, compressed images did up to ratios of 10: 1 and in MR images up to ratios of 15 : 1 Conclusion : We considered compression ratios up to 5 : 1 in Digora and CR panoramic images, up to 10 : 1 in CT images, up to 15 : 1 in MR images as clinically applicable compression ratios.

• Imaging Science in Dentistry
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• v.44 no.4
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• pp.301-305
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• 2014

Purpose: The purpose of this study was to compare the accuracy of postoperative maxillary cyst (POMC) diagnosis by panoramic radiographs versus computed tomography (CT) and by oral and maxillofacial radiologists versus non-specialists. Materials and Methods: Sixty-five maxillary sinuses with POMCs and 63 without any lesion were assessed using panoramic radiographs and CT images by five oral and maxillofacial radiologists and five non-specialists on a five-point scale. The areas under receiver operating characteristic (ROC) curves were analyzed to determine the differences in diagnostic accuracy between the two imaging modalities and between the two groups of observers. The intra-observer agreement was determined, too. Results: The diagnostic accuracy of CT images was higher than that of panoramic radiographs in both groups of observers (p<0.05). The diagnostic accuracy of oral and maxillofacial radiologists for each method was higher than that of non-specialists (p<0.05). Conclusion: The use of CT improves the diagnosis of POMC, and radiological training and experience leads to more accurate evaluation.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.1
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• pp.23-29
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• 2020

Purpose: The purpose of this retrospective study was to evaluate the method using the S-reamer and gel-type graft material by the success rate and survival rate. Materials and methods: Implantation period was from 2008 to 2014, Follow check up year is 2019. There were 59 patients and 117 implants. All implants were placed in the posterior maxilla with the sinus lift. The patients population consisted of 34 men and 25 women, ranging from 19 to 75 years. The residual bone heights were from 1 mm to 6 mm. Sinus was perforated with S-reamer without membrane tearing and gel type bone graft material was used for membrane lifting and filling the space. all implants were placed simultaneously. Panoramic X-ray was taken. After 5 - 6 months healing period, final prostheses were restored. After more 5-years implant surgery, Panoramic X-ray was obtained and X-ray analysis and clinical examination were performed. Success criteria was referred to a Buser's success critera. All implants were classified to success implant, survival implant, failed implant. A success implant was satisfying success criteria, a survival implant was a implant that was acute infection with suppuration and bone loss, a failed implant was a implant that was mobile, removed. Results: Five implants were removed, and 4 implants had infected with bone loss. Survival rate was 95.7% and success rate was 92.3%. Conclusion: This retrospective study presented that this method with S-reamer and gel-type graft material was a successful treatment without membrane tear in the condition of 1-6 mm residual bone height.

• Imaging Science in Dentistry
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• v.32 no.2
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• pp.119-122
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• 2002

Two cases of Eagle's syndrome are reported. The first case involved a 31-year-old man who complained of pain in his throat and pain at preauricular area on turning his head. Panoramic and computed tomography (CT) views showed bilateral stylohyoid ligament ossification. The symptoms were relieved after surgical removal. The second case involved a 56-year-old female whose chief complaints were a continuous dull pain and occasional 'shooting' pain on lower left molar area. During the physical examination, an ossified stylohyoid ligament was palpated at the left submandibular area. Panoramic and CT images showed prominent bilateral stylohyoid ligament ossification. CT scans also showed hypertrophy of left medial and lateral pterygoid muscles. The symptoms were relieved after medication. CT is a useful tool for the examination of ossified stylohyoid ligaments and studying the relationship between Eagle's syndrome and adjacent soft tissue.

• Imaging Science in Dentistry
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• v.34 no.3
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• pp.159-164
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• 2004

Purpose: To compare alveolar bony height of pantomograph with bony height of thin slice, multiplanar reformatted (MPR) Computed Tomograph. Materials and Methods : Panoramic radiograms of 12 young adult patients had been taken by one radologic technitian and the measurements were corrected by magnification ratio (1.20). The slice thickness of Multi-detector Computed Tomography (CT) was at least 1mm for the accuracy. The raw CT datas were imported into the V-works 4.0 (CyberMed Corp., Seoul, Korea) and transformed to MPR images. Pantomographic measurements of alveolar bone were compared to CT values by average mean bony height measurements for the accuracy. Inter-, and Intra-observer variability was evaluated. Results : There was no significant differences between height measurement of pantomography and that of CT (P>0.05). There were no significant differences in either inter-or intra-observer measurements (P>0.05). Conclusion : Pantomography showed relatively high accuracy and precision in measuring alveolar bony height.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.5
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• pp.519-526
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• 2000

Osteoporosis has recently been recognized as a major health problem in the elderly population. The disorder is manifested as a loss of bone mass accompanied by structural alteration of bone and increased incidence of fracture. Mandible also may be affected. So, I evaluated panoramic views of 66 postmenopausal women for finding the possibility of useful diagnostic mandibular parmeters of osteoporosis. To know the correlationship between skeleton and mandible, the average of the bone mineral density of lumbar from 2nd to 4th by the dual energy X-ray absorptiometry(DEXA, LUNAR DPZ. USA), and age and mandibular parameters, that is, the number of residual teeth, alveolar ridge resorption ratio, panoramic mandibular index (PMI), mandibular cortical width (MCW), angular cortical thickness (ACT), ramus cortical thickness (RCT), morphology of mandibular inferior cortical (MIC) were compared. And I divided the all tested women to the osteoporotic group and non-osteoporotic group by the use of T-score -2.0, which was derived from skeletal bone mineral density (BMD). To find the correlationship of the each group with mandibular parameters, t-test and discriminant analysis were done. The results of the t-test were that all parameters were highly related with 2 groups (p<0.05). Especially ACT, MIC, age have had even higher correlationship than others (p<0.001). The results of the discriminant analysis by the use of these ACT, MIC and age were that the discriminant function was Z = -2.973+(-1.447)$\times$(ACT)+1.131$\times$(MIC score)+(0.052)$\times$(age), the cutting score was 0.257 and the classification accuracy was 84.8%. Therefore I suggest that the consideration of the angular cortical thickness (ACT), the age of patient and the morphology of mandibular inferior cortical(MIC) may help find the osteoporosis.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.14 no.1
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• pp.81-87
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• 1984

This study was performed to observe the secondary images and to analyse the relationships between the primary and secondary images in panoramic radiograph. Using the Moritta's Panex-EC panoramic x-ray machine and the human dry skull, the author analysed 17 radiographs which were selected from 65 radiographs of the dry skull that attached the radiopaque materials, and the attached regions of the radiopaque materials were the normal anatomical structures which were important and selected as a regions for the evaluation of the secondary images effectively. The results were as follows; 1. The cervical vertebrae showed three images. The midline image was the most distorted and less clear, and bilateral images were slightly superimposed over the posterior border of the mandibular ramus. 2. In mandible, the secondary image of the posterior border of the ramus was superimposed on the opposite ramus region, and this image was elongated from the anterior border of the ramus to the lateral side of the posterior border of the ramus. The secondary image of the condyle was observed on the upper area of the coronoid process, the sigmoid notch and the condyle in opposite side. 3. In maxilla, the posterior region of the hard palate showed the secondary image on the lower part of the nasal cavity and the medial wall of the maxillary sinus. 4. The primary images of the occipital condyle and the mastoid process appeared on the same region, and only the secondary image of the occipital condyle was observed symmetrically on the opposite side with similar shape to the primary one. 5. In the cranial base, the anatomical structures of the midsagittal portions like a inferior border of the frontal sinus, sella turcica, inferior borderr of the sphenoid sinus and inferior border of the posterior part of the occipital bone showed the simillar shape between the primary and secondary images symmetrically. 6. The petrous portion of the temporal bone showed the secondary image on the lateral side of the sella-turcica, and the secondary images of the posterior border of lesser wing, superior border of greater wing of the sphenoid bone and posterior border were observed on the anterior-superior and inferior region of the sella-turcica.

• Archives of Craniofacial Surgery
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• v.24 no.4
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• pp.167-173
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• 2023

Background: Mandibular split fractures, in which the fracture occurs exclusively in the posterior wall, are uncommon. This study aimed to enhance clinicians' understanding of mandibular split fractures and offer insights for future research. Methods: This study included six patients who visited our hospital between January 2020 and June 2023 and were diagnosed with mandibular split fractures. We retrospectively collected data from patients' medical records on their age, sex, symptoms, mechanism, impact site, associated injuries, and treatment method, as well as the location, pattern, and number of fractures observed on computed tomography (CT) and panoramic images. The frequency of split fractures among all mandibular fractures was calculated. Results: The six patients included three men (50%) and three women (50%), ranging in age from 20 to 71 years (mean age, 49.8 years). The split fractures were located in the symphysis in one patient (16.7%), symphysis to parasymphysis in two patients (33.3%), parasymphysis in one patient (16.7%), and parasymphysis to the body in two patients (33.3%). Four patients (66.7%) had condylar head fractures, while two patients (33.3%) had single split fractures. The mechanism of trauma was a slip-down incident in four cases (66.7%), while two cases (33.3%) were caused by motorcycle traffic accidents. Four patients (67%) underwent intermaxillary fixation, while two patients (33%) improved with conservative treatment. Split fractures were diagnosed in all six patients on CT, whereas the fracture line was not clearly visible on panoramic images. Mandibular split fractures accounted for 5.6% of all mandibular fractures. Conclusion: This study provides insights into the clinical characteristics of rare mandibular split fractures and the diagnostic imaging findings. Furthermore, CT scans and three-dimensional image synthesis-instead of panoramic images-may be essential for accurately diagnosing mandibular fractures, including mandibular split fractures, in the future.