• 치과방사선
• /
• 제21권2호
• /
• pp.157-163
• /
• 1991

The author has evaluated the panoramic image of the maxillary sinus according to the skull position. The lead foils were attached to the five walls of the maxillary sinus and the inferior turbinate individually. The skull was located in three positions; standard position, 20㎜ forward position and chin-down position. The obtained results were as follows: 1. In standard position, the medial wall was superimposed upon most of the panoramic antral image. The anterior wall and the posterolateral wall were superimposed upon the medial half and the lateral third respectively. 2. In forward position, the width of the panoramic antral image was diminished generally. The anterior wall was superimposed upon most of the panoramic antral image and the posterolateral wall appeared narrowly at the most lateral portion of the panoramic antral image. 3. In chin-down position, there was no significant difference in comparison to the standard position. 4. Inferior turbinate was not superimposed upon the panoramic antral image.

• Imaging Science in Dentistry
• /
• 제33권4호
• /
• pp.199-205
• /
• 2003

Purpose: To compare the visibility of the mandibular canal at the different radiographic methods such as conventional panoramic radiographs, Vimplant multi planar reformatting (MPR)-CT panoramic images, Vimplant MPR-CT paraxial images and film-based DentaScan MPR-CT images. Materials and Methods: Data of 11 mandibular dental implant patients, who had been planned treatment utilizing both panoramic and MPR-CT examination with DentaScan software (GE Medical systems, Milwaukee, USA), were used in this study. The archived axial CT data stored on CD-R discs were transferred to a personal computer with 17' LCD monitor. Paraxial and panoramic images were reconstructed using Vimplant software (CyberMed Inc., Seoul, Korea). Conventional panoramic radiographs, monitor-based Vimplant MPR-CT panoramic images, monitor-based Vimplant MPR-CT paraxial images, and film-based DentaScan MPR-CT images were evaluated for visibility of the mandibular canal at the mental foramen, 1 cm, 2 cm, and 3 cm posterior to mental foramen using the 4-point grading score. Results: Vimplant MPR-CT panoramic, paraxial, and DentaScan MPR-CT images revealed significantly clearer images than conventional panoramic radiographs. Particularly at the region 1 em posterior to mental foramen, conventional panoramic radiographs showed a markedly lower percentage of 'excellent' mandibular canal images than images produced by other modalites. Vimplant MPR-CT and DentaScan MPR-CT images did not show significant difference in visibility of the mandibular canal. Conclusion: The study results show that Vimplant and DentaScan MPR-CT imaging systems offer significantly better images of the mandibular canal than conventional panoramic radiograph.

• 치과방사선
• /
• 제23권2호
• /
• pp.207-211
• /
• 1993

The auther has evaluated the panoramic image of the mandibular condyle according to its horizontal codylar angle(0°, 10°, 20°, 30°, 40°) and intercondylar distance( 9.5, 11.0, 12.5, 14.0㎝). The Results were as follows: 1. In all horizontal condylar angle, the farther the intercondylar distance was, the smaller the horizontal length in radiogram was. 2. The increased the horizontal condylar angle was, the longer in horizontal direction and the shorter in vertical direction the image of superior condylar surface was. 3. In case of large horizontal condylar angle, the real mesial surface of condyle was projected to the posterior surface on radiograph.

• 치과방사선
• /
• 제12권1호
• /
• pp.115-121
• /
• 1982

In the study of the focal trough of panoramic radiograph, using the Moritta compony Panex-EC a series of 48 exposures were: taken with the 6-18 brass pins placed in the holes of the plastic model plate, then eveluated by 4 observers. The author analyzed the focal trough defined by the sharpness criteria and calcuated the vertical and horizontal magnification range in the corrected focal trough. The results were as follows; 1. Continuous focal trough was not defined in the anterior region using a very high degree of sharpness. 2. As degree of sharpness used in the analysis became less, focal trough was continuous in the anterior and posterior regions, symmetrized bilaterally, and the widths of the focal trough increased more in the posterior region. e. As sharpness criteria were reduced, the percentage range of image magnification increased on both vertical and horizontal magnification, and especially the percentage range of horizontal magnification was greater than that of vertical magnification.

• 치과방사선
• /
• 제16권1호
• /
• pp.59-68
• /
• 1986

The purpose of this investigation was to locate the central plane of the image layer on the panoramic machine relative to a specific point on the machine. In the study of the central plane of the image layer of panoramic radiograph, using the Morrita Company PANEX-EC a series of 33 exposures were taken with the 4-5 experimental pins placed in the holes of the plastic model plate, then evaluated by human eye. The author analyzed the central plane of the image layer by Mitutoyo-A-221 and calculated horizontal and vertical magnification ratio in the central plane of the image layer determined experimentally. The results were as follows: 1. The location of the central plane of the image layer determined experimentally was to lateral, compared with manufactural central plane. 2. Horizontal magnification ratio in the central plane of the image layer determined experimentally was 9.25%. 3. Vertical magnification ratio in the central plane of the image layer determined experimentally was 9.17%.

• Imaging Science in Dentistry
• /
• 제43권3호
• /
• pp.197-200
• /
• 2013

Florid osseous dysplasia (FOD) is an uncommon, benign, cemento-osseous lesion of the jaws. The etiology of FOD is still unknown. It is often asymptomatic and may be identified on routine dental radiographs. The classic radiographic appearance of FOD is amorphous, lobulated, mixed radiolucent/radiopaque masses of cotton-wool appearance with a sclerotic border in the jaws. In our case the lesion was found incidentally on routine periapical radiographs taken for restored teeth and edentulous areas. For further and detailed examination, a panoramic radiograph and cone-beam computed tomograph (CBCT) were taken. The panoramic radiograph and CBCT revealed maxillary bilateral and symmetrical, non-expansile, well-defined, round, radiopaque masses in contact with the root of the maxillary right second molar and left first molar teeth. Our aim in presenting this case report was to highlight the importance of imaging in diagnosis of FOD.

• 치과방사선
• /
• 제20권2호
• /
• pp.163-167
• /
• 1990

The author has evaluated the panoramic image of the mandibular condyle according to its horizontal condylar angle (0˚, 10˚, 20°, 30°, 40°) and mandibular position (standard, 25㎜ forward and reverse position). The results were as follows: 1. The larger the horizontal condylar angle was, the larger the horizontal magnification was in all positions. 2. In case of small horizontal condylar angle, profile view could be obtained in 25㎜ forward and reverse position. 3. In case of large horizontal condylar angle, profile view could not be obtained in any positions.

• Imaging Science in Dentistry
• /
• 제39권2호
• /
• pp.69-73
• /
• 2009

Purpose: This study compared panoramic radiography and cone beam computed tomography (CBCT) for evaluating the relationship between the maxillary sinus floor and the roots of maxillary molars. Materials and Methods: Paired panoramic radiographs and CBCT images from 97 subjects were analysed. This analysis classified 388 maxillary molars according to their relationship to the maxillary sinus floor on panoramic radiograph and CBCT. Correlations between these two radiographic techniques were examined. Results: Maxillary molar roots that were separate from the sinus floor showed the same classification in 100% of the cases when using these two imaging techniques. The corresponding percentage for such roots that were in contact with the sinus floor was 75%. When roots overlapped the maxillary sinus floor on panoramic radiographs, only 26.4% of maxillary first molars and 60.0% of second molars showed protrusion of roots into the sinus with CBCT. Conclusion : The results of the study suggest that roots projecting into the sinus on panoramic radiographs require a three-dimensional image in order to analyze the proximity of their apex to the sinus floor. (Korean J Oral Maxillofac Radiol2009; 39 : 69-73)

• Imaging Science in Dentistry
• /
• 제52권3호
• /
• pp.275-281
• /
• 2022

Purpose: The aim of this study was to assess the performance of a deep learning system for permanent tooth germ detection on pediatric panoramic radiographs. Materials and Methods: In total, 4518 anonymized panoramic radiographs of children between 5 and 13 years of age were collected. YOLOv4, a convolutional neural network (CNN)-based object detection model, was used to automatically detect permanent tooth germs. Panoramic images of children processed in LabelImg were trained and tested in the YOLOv4 algorithm. True-positive, false-positive, and false-negative rates were calculated. A confusion matrix was used to evaluate the performance of the model. Results: The YOLOv4 model, which detected permanent tooth germs on pediatric panoramic radiographs, provided an average precision value of 94.16% and an F1 value of 0.90, indicating a high level of significance. The average YOLOv4 inference time was 90 ms. Conclusion: The detection of permanent tooth germs on pediatric panoramic X-rays using a deep learning-based approach may facilitate the early diagnosis of tooth deficiency or supernumerary teeth and help dental practitioners find more accurate treatment options while saving time and effort

• Imaging Science in Dentistry
• /
• 제31권4호
• /
• pp.205-207
• /
• 2001

Purpose : The aim of present study is to estimate the relationship among reference lines used for taking the extraoral radiography and panoramic radiography. Materials and Methods: Lateral cephalographs of 40 adults, aged 22 to 30 years were taken. Angles between reference lines (Frankfort line, canthomeatal line, infraorbitomeatal line, and occlusal plane) were measured. Results: Angles between Frankfort line and canthomeatal line, Frankfort line and infraorbitomeatal line, Frankfort line and occlusal plane, canthomeatal line and infraorbitomeatal line, canthomeatal line and occlusal plane, and infraorbitomeatal line and occlusal plane were 16.1° (±2.2), 5.8° (±2.4), 8.7° (±3.5), 10.3° (±1.3), 24.8° (±4.0), and 14.5° (±4.4),respectively. Conclusion: Angle between frankfort and canthomeatal line is very different with commonly known angle. Frankfort horizontal reference lines used for panoramic radiography need an exact definition and more accurate standard is needed for the taking of panoramic radiograph.