• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.3
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• pp.230-234
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• 2006

Purpose: This study presents radiographic and laboratory analysis and comparison of bone resorption rate of grafted endochondral bone and intramembranous bone on the aspect of height and volumetric change. Patients and Methods: 18 partially edentulous patients who needed alveolar ridge augmentation for implant placement during the years 2002 to 2004 were selected for this study. Group A consisted of 5 males & 3 females who were treated with intraoral(intramembranous) bone and Group B consisted of 8 males & 2 females who were treated with iliac(endochondral) bone. Non-standard periapical X-ray was taken at day 1, 2 month, 4 months, 8 months after the surgery. Resorption rate of grafted bone were measured on these X-rays and compared. Also we calculated volume of grafted bone with models which was fabricated at 1.5 months, 6 months. Results: There was bone resorption in both groups. Group B showed more bone resorption than Group A. In Group A, the resorption rate according to the radiographic measurements was 9.81 %, and resorption rate according to volumetric measurement was 16.5 %. In group B, the resorption rate according to the radiographic measurements was 15.9 %, and resorption rate according to volumetric measurement was 30.6 %. Significant difference is on radiographic resorption of post-op 2, 4, 8 months on two groups (P < 0.05). Also significant difference is on volume resorption on two groups (P < 0.05). Conclusion: We found that more bone resorption occurred with iliac(endochondral) bone and when we use intraoral bone, that bone can maintain their vitality for alveolar ridge augmentation.

• 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.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.24 no.2
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• pp.427-437
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• 1994

Clinical examination, photometric evaluation, & radiographic analysis have been used to evaluate the asymmetry of the face. Commonly used skull radiographs to assess skeletal asymmetry include poatero-anterior cephalometries, submentovertex view, & panoramic view. The purpose of this study is the comparison of the reliance of the postero-anterior cephalometric view, submentovertex view, & panoramic view in the asymmetry evaluation. All measurements were performed on the each radiographs of 31 control group & 30 asymmetric group. The measurements are MSL(midsagittal plane)-Co, MSL-Go, MSL-Me, MSL-Al, MSL-Bl, Mn. Ramus Height(Co-Go), Mn. Body Length(Go-Me), and Total Mn. Length(Co-Me). The results were as follows: 1. The lack of either a right-sided or left-sided asymmetric dominant was found. 2. The postero-anterior cephalometric view & submentovertex view relatively agreed with each other in the result. The postero-anterior cephalometric view & submentovertex view had the clinical reliability & effectiveness in the diagnosis of the skeletal asymmetry(p<0.05). 3. The panoramic view showed more magnification compared to the other radiographs. In the vertical measurements the panoramic view had clinical reliability relatively(p<0.05). But we cannot rely on the horizontal measurements in the panoramic view(p>0.05).

• Imaging Science in Dentistry
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• v.35 no.3
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• pp.115-119
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• 2005

Purpose : To evaluate the magnification error percentage in repeatedly taken panoramic radiographs of same patient and machine. Materials and Methods : 92 panoramic radiographs from 46 patients were traced and 30 horizontal and vertical measurements were made with digital sliding caliper. The results were compared with paired t-test. Results : There was no statistically significant difference between the two measurements. The overall difference as percentage error was $6.19\pm5.60\%$. The largest error as $14.61\pm12.44\%$ was found at condylar height 1, and smallest as $1.86\pm1.61\%$ at mandibular height. Overall vertical error excluding condylar height 1 was $3.76\pm3.97\%$, and the horizontal error $6.88\pm5.92\%$. Conclusion . Repeatedly taken panoramic radiographs of the same patient and machine was reliable since there was no significant percentage error difference but the percentage error ranged from $1.86\pm1.61\%\;to\;14.61\pm12.44\%$ indicating the error depends on the measuring site.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.206-207
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• 2002

The effective dose due to the X-Ray radiography in the patient positioning for the heavy ion radiotherapy was measured on three regions, chest, upper-abdomen and pelvis. All the radiographic systems and the conditions used in the measurements were same as the clinical trial being performed in National Institute of Radiological Sciences, Japan. The organ or tissue for measurements was selected by following ICRP60$^1$ and the effective dose was calculated from measured organ doses and the surface dose.

• Imaging Science in Dentistry
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• v.43 no.2
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• pp.77-84
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• 2013

Purpose: This study aimed to provide comparative measurements of the effective dose from direct and indirect digital panoramic units according to phantoms and exposure parameters. Materials and Methods: Dose measurements were carried out using a head phantom representing an average man (175 cm tall, 73.5 kg male) and a limbless whole body phantom representing an average woman (155 cm tall, 50 kg female). Lithium fluoride thermoluminescent dosimeter (TLD) chips were used for the dosimeter. Two direct and 2 indirect digital panoramic units were evaluated in this study. Effective doses were derived using 2007 International Commission on Radiological Protection (ICRP) recommendations. Results: The effective doses of the 4 digital panoramic units ranged between $8.9{\mu}Sv$ and $37.8{\mu}Sv$. By using the head phantom, the effective doses from the direct digital panoramic units ($37.8{\mu}Sv$, $27.6{\mu}Sv$) were higher than those from the indirect units ($8.9{\mu}Sv$, $15.9{\mu}Sv$). The same panoramic unit showed the difference in effective doses according to the gender of the phantom, numbers and locations of TLDs, and kVp. Conclusion: To reasonably assess the radiation risk from various dental radiographic units, the effective doses should be obtained with the same numbers and locations of TLDs, and with standard hospital exposure. After that, it is necessary to survey the effective doses from various dental radiographic units according to the gender with the corresponding phantom.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.17 no.1
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• pp.271-278
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• 1987

The purpose of the present study was to investigate associations between periapical and bitewing techniques by assessing the crestal alveolar bone. This article also reports the ability of these two techniques to correctly detect evidence of interproximal dental caries, and comparison between the interproximal overlapping of teeth. Bitewing and periapical radiographs were used from posterior quardants of 243 dental students in Seoul National University. The distance from cemento-enamel junction to the alveolar crest (CEJ-AC) was measured for each proximal surface from the distal of cuspid to the distal of second molar. Data were arranged according to the proximal surface examined, and bitewing and periapical measurements were compared using paired tests. The obtained results were as follows: 1. In maxilla, a significant t ratio with a P value of 0.05 or less reached for 100% and in mandible, reached for 94%. 2. The anatomic limitations imposed on periapical radiographic technique, most often result in somewhat foreshortened radiographic images. This situation would tend to be accentuated by the anatomical restrictions of the hard palate. 3. Consequently, since the significant differences frequently exist between measurements obtained from bitewing and periapical techniques, it is important to define which technique is used. 4. The number of the interproximal overlapping was the largest medial side of the maxillary second molar, while the smallest at the distal side of the mandibular second premolar. And the overall number of the interproximal overlapping was more (538) in the periapical technique than in the bitewing technique (372). 5. The interproximal dental carious lesions were detected more (74) on the bitewing films than on the periapical ones (23). The fact was resulted from the small number of interproximal overlapping and relative easi- ness of obtaining horizontal angulation in taking the bitewing radiographs.

• Imaging Science in Dentistry
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• v.43 no.3
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• pp.185-190
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• 2013

Purpose: The aim of the present study was to evaluate the measurement accuracy of endodontic file length on periapical digital radiography after application of noise reduction digital enhancement. Materials and Methods: Thirty-five human single-rooted permanent teeth with canals measuring 20-24 mm in length were selected. ISO #08 endodontic files were placed in the root canals of the teeth. The file lengths were measured with a digital caliper as the standard value. Standard periapical digital images were obtained using the Digora digital radiographic system and a dental X-ray unit. In order to produce the enhanced images, the noise reduction option was applied. Two blinded radiologists measured the file lengths on the original and enhanced images. The measurements were compared by repeated measures ANOVA and the Bonferroni test (${\alpha}=0.05$). Results: Both the original and enhanced digital images provided significantly longer measurements compared with the standard value (P<0.05). There were no significant differences between the measurement accuracy of the original and enhanced images (P>0.05). Conclusion: Noise reduction digital enhancement did not influence the measurement accuracy of the length of the thin endodontic files on the digital periapical radiographs despite the fact that noise reduction could result in the elimination of fine details of the images.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.28 no.1
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• pp.7-16
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• 1998

The Scanora/sup (R)/ X-ray unit uses the principles of narrow beam radiography and spiral tomography. Starting with a panoramic overview as a scout image. multiple tomographic projections could be selected. This study evaluated the accuracy of spiral tomography in comparison to routine panoramic radiography for dental implant treatment planning. An experimental study was performed on a cadaver mandible to assess the accuracy of panoramic radiography and spiral tomography film images for measurement of metallic spheres. After radiographic images of the metallic spheres on the surgical stent were measured and corrected for a fixed magnification of radiographic images. following results were obtained. 1. In the optimal position of the mandible. the minimal horizontal and vertical distortion was evident in the panoramic radiography images. The mean horizontal and vertical magnification error in anterior sites was 5.25％ and 0.75％. respectively. The mean horizontal and vertical magnification error in posterior sites was 0.50％ and 1.50％. respectively. 2. In the displaced forward or in an eccentric position of the mandible. the magnification error of the panoramic radiography images increased significantly over the optimal position. Overall, the mean horizontal magnification error of the anterior site in the different positions changed dramatically within a range of -17.25％ to 39.00％, compared to the posterior range of -5.25％ to 8.50％. However, the mean vertical magnification error stayed with the range of 0.5％ to 3.75％ for all the mandibular positions. 3. The magnification effects in the tomographic scans were nearly identical for the anterior and posterior with a range of 2.00％ to 5.75％ in the horizontal and 4.50％ to 5.50％ in the vertical dimension, respectively. 4. A statistically significant difference between the anterior and posterior measurements was found in the horizontal measurements of the panoramic radiography images of the displaced forward and backward position of the mandible(P<0.05). Also a significant difference between the optimal panoramic and tomographic projections was found only in the vertical measurement(P<0.05).

• Journal of the Korean Society of Physical Medicine
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• v.4 no.4
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• pp.231-240
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• 2009

Purpose：The aim of this study was to determine the effect of active sling exercise on shoulder subluxation in hemiplegic patients. Methods：Twenty persons with shoulder subluxation were randomly divided into two groups; the experimental group(10 persons) and the control group(10 persons). Usual physical therapy and occupational therapy were applied in all groups in a day for 4 weeks. Additionally the experimental group was received 30 minutes sling active exercise (flexion, extention, adduction, abduction, intenal rotation, external rotation, horizontal adduction, horizontal abduction) for shoulder joint in a day for 4 weeks. I investigated the therapeutic effect of sling exercise through the Wolf motor function test (WMFT), Quantitative radiographic measurements and range of motion test at pre and post intervention period. Results：The passive range of motion was significantly increased in the experimental group compare with the control group. However, the active range of motion was no statistically significantly difference in both of the experimental and the control group. The level of WMFT was significantly decreased in the experimental group compared with control group. Although, there was no significantly difference the degree of the shoulder subluxation was more decreased in experimental group than control group. Conclusion：Taken together, these results suggest that sling exercise could be beneficial therapeutic method for hemiplegic shoulder. But to generalize it, more study and exercise program might be needed to confirm its availability.