• Journal of Korean society of Dental Hygiene
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• v.11 no.5
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• pp.783-790
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• 2011

Objectives : The purpose of this study was to examine students' difficulties in the process of oral radiography practice, to raise awareness of the importance and necessity of oral radiography and decipher, and to provide some information on effective ways of oral radiography practice. Methods : The subjects in this study were 285 dental hygiene students at K college, who included 153 sophomores and 132 graduates-to-be from June to November, 2010. Results : 1. The parts of the anatomy structure that they found it most difficult to decipher were maxillary molar(25.3%) and lower molar(22.1%). 2. They made during oral radiography was an improper film positioning(35.1%). 3. The part of bisecting technique was adjusting vertical and horizontal angles(53.0%). 4. The part of paralleling technique was positioning XCP in the oral cavity(44.2%). 5. The part of bite-wing technique was adjusting vertical and horizontal angles(38.2%). 6. The part of occlusion technique was positioning film and tube head(36.5%). 7. The part of panorama technique was finding out program setting(42.5%). Conclusions : The findings of the study indicated that in terms of anatomy structure decipher, it's especially difficult to decipher maxillary molar and lower molar, and that film positioning was difficult to do in the process of oral radiography. What difficulties they faced in applying each kind of oral radiography techniques and which part of the oral cavity they found it hard to radiograph were analyzed as well in this study. Given the findings of the study, more intensive practice is required to help students to acquire accurate oral radiography techniques to ensure their successful job performance in the future.

• Imaging Science in Dentistry
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• v.31 no.3
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• pp.129-133
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• 2001

Purpose: To compare the copper equivalent values measured at premolar and molar areas in the copper equivalent images of panoramic and intraoral radiographs and to evaluate the possibility of the copper equivalent images of panorama for the assessment the bone density. Materials and Methods : Intraoral radiograms at mandibular premolar and molar area and panoramas of 6 human dry skulls were taken with copper-step wedge by Heliodent MD (Siemens Co., Germany) and by Planmeca (PM 2002 CC, Planmeca, Helsinki, Finland) were used for experiment. The copper equivalent values measured at premolar and molar areas in the copper equivalent im ages of panorama and intraoral film were compared. Results: The copper equivalent values were ranged 0.20 mmCu-0.44 mmCu at the molar areas, 0.05 mmCu-0.31 mmCu at the premolar areas on panoramic images. There were no significant differences (p>0.5) between the copper equivalent values on intraoral images and those on panoramic images measured at premolar areas and molar areas respectively. The correlation coefficient between the copper equivalent values on intraoral images and those on panoramic images was respectively 0.8495 at molar areas and 0.6184 at premolar areas. Conclusions : The copper equivalent images of panorama for the assessment the bone density appeared to be significant at molar area compared with the one of intraoral radiograph.

• Korean Journal of Digital Imaging in Medicine
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• v.14 no.2
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• pp.15-22
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• 2012

The purpose of this study was to measure the absorbed dose and calculate the effective dose for cone beam computed tomography (CBCT) and panorama units and to estimate usefulness of x-ray protective. Rando phantom and glass dosimeters were used for dosimetry. The absorbed doses were measured at 15 organs and 14 remainder from correspond to ICRP 2007 recommendations. The absorbed dose was highest in salivary glands as measured CBCT 2.420mGy, panorama 0.307mGy. Absorbed dose in another organs were high in order of thyroid, brain, skin, esophagus. The effective dose was CBCT 0.100mSv, panorama 0.011mSv and effective dose of panorama was higher than that of CBCT by 10 times. In case of wearing x-ray protective, reducing effective dose of CBCT by 0.066mSv (66%) and panorama by 0.008mSv (72%). Effective dose were reduced by radiological shielding but it needs further optimization studies, where dosimetric data are analyzed in combination with image quality with keep the patients' exposure as low as possible.

• Imaging Science in Dentistry
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• v.48 no.4
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• pp.255-259
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• 2018

Purpose: This study proposes a new ball-type phantom for evaluation of the image layer of panoramic radiography. Materials and Methods: The arch shape of an acrylic resin phantom was derived from average data on the lower dental arch in Korean adult males. Metal balls with a 2-mm diameter were placed along the center line of the phantom at a 4-mm mesiodistal interval. Additional metal balls were placed along the 22 arch-shaped lines that ran parallel to the center line at 2-mm buccolingual intervals. The height of each ball in the horizontal plane was spaced by 2.5 mm, and consequently, the balls appeared oblique when viewed from the side. The resulting phantom was named the Panorama phantom. The distortion rate of the balls in the acquired image was measured by automatically calculating the difference between the vertical and horizontal length using $MATLAB^{(R)}$. Image layer boundaries were obtained by applying various distortion rate thresholds. Results: Most areas containing metal balls (91.5%) were included in the image layer with a 50% distortion rate threshold. When a 5% distortion rate threshold was applied, the image layer was formed with a small buccolingual width along the arch-shaped center line. However, it was medially located in the temporomandibular joint region. Conclusion: The Panorama phantom could be used to evaluate the image layer of panoramic radiography, including all mesiodistal areas with large buccolingual width.

• Imaging Science in Dentistry
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• v.33 no.3
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• pp.137-141
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• 2003

Purpose: To evaluate the precision of measurements taken of dental implants in bucco-lingually sectioned views of the maxilla by linear tomograms of the panorama and to assess the visibility of the inferior wall of the maxillary sinus. Materials and Methods : Eighty sites prepared with implants of gutta percha cone in the sockets of the upper premolars and molars of 10 dry skulls were radiographically examined using linear tomograms of panorama, and scanned coronally and axially by computed tomography. The differences in mm between the measurements in bucco-lingually sectioned images of maxillary alveolar bone and the true length and width of the implanted gutta percha cones were compared as mean values (mean) and standard deviations (SD) for each radiographic technique. Linear tomography of panorama was compared with computed tomography for visualization of the relationship between the inferior wall of maxillary sinus and the end of each implant. Results: The deviations between the actual implant length and the measured values taken from the linear tomograms (0.44±0.39 mm) was significantly less than the measured values from the multiplanar reconstructed images of the axially scanned computed tomogram (1.21 ± 0.90 mm). There was statistically significant difference (p < 0.05) between two techniques in the differences between the measurements and true implant length. The relationship of the inferior border of maxillary sinus with end of implant was worse identified with the linear tomogram of panorama (68%) than the multiplanar reconstructed image of axially scanned computed tomogram (99%). Conclusion: We could not find any differences in the accuracy of length measurement between the linear tomogram of panorama and computed tomogram, but computed tomogram allowed for a better visualization of the inferior wall of the maxillary sinus than the linear tomogram.

• Journal of the Korean Society of Radiology
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• v.9 no.7
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• pp.433-438
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• 2015

To evaluate the radiation exposure level based on radiation workers' locations in dental radiography, the radiation dose rate in the radiographic room, lead glass, and operation system was measured. To that end, various devices were used, such as a Standard(Max-GLS, Shinhung), a panorama (PCH-2500, Vatech), a cephalometric radiography (PCH-2500), and a cone beam CT (PHT-30LFO, Vatech), as well as a PM1405 equipment as a radiation meter. Radiography conditions were set the same as the factors used in the clinical setting. As the result, the cone beam CT turned out the highest with 98 uSv and the standard showed the lowest level with 0.4 uSv/h. The panorama was measured to be higher than the Cephalo due to its different focus mode. On the lead glass surface and in the operation stand, the oral radiography device, panoramic, and Cephalo all were measured below the recording level. However, the cone beam CT was measured to have the leakage dose. Thus, radiation involved workers should be equipped with appropriate protection tools and reduce radiography time as much as possible. In addition, the structure of the radiation chamber should be also designed efficiently. Dental radiography has continued to grow in recent years, so it is necessary take appropriate protection measures for patients and radiation workers.

• Imaging Science in Dentistry
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• v.33 no.3
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• pp.131-135
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• 2003

Purpose: To determine whether the mandibular radiomorphometric indices in panoramic radiography are correlated with the bone mineral density of Cu-equivalent images in intraoral film. Materials and Methods: The bone mineral density (BMD) of the mandibular premolar area was measured in the Cu-equivalent image of intraoral film. The Panoramic Mandibular Index (PMI) and Mandibular Cortical Width (MCW) were measured in panoramic radiographs of six dry mandibles, and the Pearson correlation between PMI, MCW, and BMD were tested. Results: There were no significant correlations between PMI and BMD (r = 0.280), nor between MCW and BMD (r =0.237). Conclusion: The results show that PMI and MCW were poor diagnostic indicators of mandibular BMD in the six dry mandibles used in this study. The correlationship between the mandibular radiomorphometric indices (PMI and MCW) and mandibular BMD needs to be researched further using large in vivo patient samples.

• Imaging Science in Dentistry
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• v.30 no.4
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• pp.259-263
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• 2000

Purpose: Upper cervical vertebrae are commonly imaged together with the jaw bones in panoramic radiography. There have been many studies investigating the possible role of mandible as an indicator of osteoporosis. But the result doesn't show unanimity. This study measured bone densities of mandible and second and third cervical vertebrae to find out any relationship between these two areas. These results may contribute in panorama being used as a screening method in detecting possible osteoporotic patient. Materials and Methods: Randomly selected 226 digitized panoramic images with cervical vertebrae shadows from 156 dental patients between 5 to 80 years of age were used. And the bone densities of second and third cervical vertebrae, apical areas of first and second mandibular molars and interdental areas were measured. The bone density measurements were restricted to the cancellous bone and the average and standard deviations and paired t-tests were done to each measurements. Results: All the measurements were statistically significantly related. The best relationship was found between the third cervical vertebrae and first and second mandibular apical areas. The average and standard deviations of the measured bone density ratios of these areas were 1.20±0.45 and 1.34±0.48 each. Conclusion: Patients whose panoramic bone density of the third cervical vertebrae are much below those of mandibular first or second molar apical areas may have osteoporosis.

• Imaging Science in Dentistry
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• v.31 no.4
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• pp.209-214
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• 2001

Purpose: To investigate the ability of double TMJ view by multifunctional panorama to view the bony components and the space of the temporomandibular joint. Materials and Methods: Ten dry skulls fitted with resin shims over the articular surface of the condyle were used to reproduce the temporomandibular joint space. Fine metal wires were attached to the three portions of contours of the condylar head and the articular eminence. With 10 dry skulls and 20 cases having TMJ dysfunction, double TMJ views by multifunctional panorama (Planmeca 2002 Proline CC) and transcranial views were taken, analyzed from the anatomical view point, and compared statistically in view of the widths of the posterior joint space and the condylar head. Results: In double TMJ view, the supero-anterior part of the condyle represented the lateral 1/3, the most superior part represented center portion, and the posterior part medial l/3 of the condyle. In maximum mouth opening, no other structures were superimposed with the condyle in double TMJ view. In double TMJ view, petrous bone was moderately superimposed with the superior part of the condyle and the posterior increment of angle exposure made wider the images of the articular eminence and the condyle. The tendency of reduction in the posterior joint space appeared in the side of TMJ dysfunction compared with the normal side. The posterior joint spaces in double TMJ view were statistically wider (p<0.05) than those in transcranial view. The correlation coefficient was 0.5179 between the widths of the posterior joint spaces in two radiographic views. Conclusions: Double TMJ view can be substituted for transcranial view in evaluating the TMJ dysfunction.

• Imaging Science in Dentistry
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• v.34 no.2
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• pp.69-74
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• 2004

Purpose : This study was conducted to compare the radiomorphometric indices of the mandible on panoramic radiographs among three groups of normal, osteopenia and osteoporosis and to determine whether panoramic indices have validity in predicting osteoporotic risk. Materials and Methods: Ninty-four postmenupausal women aged 42-72 years (mean 62±7.5) were examined using dual energy X-ray absorptionmetry (DEXA) of the lumbar and classified into three groups by WHO classification. Panoramic mandibular index (PMI), mandibular cortical thickness (Mental index (MI), Antegonial index (AI), Gonial index (G!)) and the mandibular cortical index (MCI) were measured bilaterally on panoramic radiographs and analyzed. Results: There were signigicant differences among normal, osteopenic and osteoporoti groups in PMI (I), PMI (S), MI, AI, GI and MCI. The sensitivities of the MCI (93%) and the combination index of MCI and MI (90%) in diagnosing osteopenic/osteoporotic cases were high. Conclusion: The widths and shapes of the mandibular cortical bone on panoramic radiography may highly reflect the systemic osteopenic/osteoporotic conditions of the patients.