• Journal of Periodontal and Implant Science
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• 제28권3호
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• pp.523-531
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• 1998

The purpose of this investigation was to examine the pattern of progression of periodontitis and the change in the extent and severity of the periodontal condition in young adults. Fourteen subjects with periodontitis, 11 males and 3 females in the age range 22-26, participated in the study. Following a baseline examination, the subjects were monitored for gingival index, probing pocket depth, gingival recession, probing attachment level and radiogrphic crestal bone height for 24 months without therapy. Re-examination were performed after 12 and 24 months. Gingival index, probing pocket depth, gingival recession and probing attachment level were assesed at 6 locations per tooth, and crestal bone height was assessed by subtraction radiography. The results from the follow-up examination revealed that the subjects underwent minor changes with respect to a series of different clinical parameters. The mean values of gingival index was improved, however, the mean values of probing pocket depth, gingival recession, probing attchment level and crestal bone height showed no significant change between baseline and the re-examination after 1 and 2 years.

• Journal of Periodontal and Implant Science
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• 제32권1호
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• pp.173-186
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• 2002

The purpose of this study was to evaluate effect of platelet rich plasma on the treatment of Grade II furcation involvement, with Demineralized Freeze-Dried Bone(Dembone(R)) and bioabsorable membrane(BioMesh(R)) in humans by digital subtraction radiography. 12 teeth(control group) were treated with Demineralized Freeze-Dried Bone(Dembone(R)) and bioabsorable membrane(BioMesh(R)), and 12 teeth(test group) were treated with Demineralized Freeze-Dried Bone(Dembone(R)), bioabsorable membrane(BioMesh(R)) and Platelet Rich Plasma. The change of bone density was assessed by digital subtraction radiography in this study. The change of mineral content by as much as 5%(vol) could be perceived in the subtracted images. The change of mineral content was assessed in the method that two radiographs are put into computer program to be overlapped and the previous image is subtracted by the later one. Both groups were statistically analyzed by Wilcoxon signed Ranks Test and Mann-whitney Test using SPSS program (5% significance level). The results were as follows: 1. In test group, the radiopacity in 3 months after surgery were significantly increased than 1 month after surgery(p<0.05). However. there were no significant difference between 1 month after surgery and 3 months after surgery in control group(p>0.05). 2. In test and control group, the radiopacity in 6 months after surgery were significantly increased than 1 month after surgery(p<0.05) 3. In test and control group, the radiopacity in 6 months after surgery were significantly increased than 3 months after surgery(p<0.05). 4. There were no significant difference between test group and control group at 1 month, 3 months after surgery, but radiopacity in test group were significantly increased than control group at 6 months after surgery(p<0.05). In conclusion, Platelet Rich Plasma can enhance bone density.

• Journal of Periodontal and Implant Science
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• 제31권2호
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• pp.465-475
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• 2001

The purpose of this study was to evaluate effect of platelet rich plasma on the treatment of Grade II furcation involvement, with and without porous resorbable calcium carbonate($Biocoral^{(R)}$)in humans by digital subtraction radiography. 15 teeth(control group) were treated with porous resorbable calcium carbonate($Biocoral^{\(R)}$), and 15 teeth(test group) were treated with porous resorbable calcium carbonate($Biocoral^{(R)}$) and Platelet Rich Plasma. The change of bone density was assessed by digital subtraction radiography in this study. The change of mineral content by as much as 5%(vol) could be perceived in the subtracted images. The change of mineral content was assessed in the method that two radiographs are put into computer program to be overlapped and the previous image is subtracted by the later one. Both groups were statistically analyzed by Wilcoxon signed Ranks Test and Mann-whitney Test using SPSS program(5% significance level). The results were as follows: 1. In test group, the radiolucency in 3 months after surgry were significantly increased than 1 month after surgery(p<0.05). 2. In test group, there were no significant difference between 1 month after surgery and 6 months after surgery(p>0.05). 3. In test group, the radiopacity in 6 months after surgery were significantly increased than 3 months after surgery(p<0.05). 4. In control group, the radiolucency in 3 months and 6 months after surgery were significantly increased than 1 month after surgery(p<0.05). 5. In control group, the radiopacity in 6 months after surgery were significantly increased than 3 months after surgery(p<0.05). 6. There were no significant difference between test group and control group at 1 month, 3 months after surgery, but radiopacity in test group were significantly increased than control group at 6 months after surgery(p<0.05). In conclusion, Platelet Rich Plasma can enhance bone density.

• Imaging Science in Dentistry
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• 제32권2호
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• pp.107-111
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• 2002

Purpose : To compare the accuracy of digital subtraction images acquired by two different methods different in positioning four reference points for geometrical standardization. Materials and Methods : A total of 36 digital radiographic images of 6 volunteers were taken at the areas of the incisor, premolar, and molar of both the maxilla and mandible using the Digora system. Each image was moved 4 mm vertically and horizontally. Four oral and maxillofacial radiologists performed digital subtraction radiography between the paired images before and after movement using Emago (Oral Diagnostic Systems, Amsterdam, The Netherlands) and Sunny (Biomedisys Co., Seoul, Korea). The standard deviation of the internal gray value in Region of Interest (ROI) was statistically analyzed between the two programs using the paired t-test. Results : The standard deviation of pixel gray values from the digital subtraction images using the Sunny program were lower than that of the Emago program (p<0.05). All observers showed significant differences between each other when the Sunny program was used (p<0.05), but one observer showed a significantly higher score than other observers when they used Emago (p<0.05). The standard deviations of premolar area from both Sunny and Emago programs were significantly higher than those of anterior and molar regions (p<0.05). Conclusion: The subtracted images using the Sunny program were more accurate and sensitive than those taken using the Emago program.

• 전자공학회논문지
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• 제53권10호
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• pp.138-142
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• 2016

듀얼 에너지 디지털 촬영법 (dual-energy digital radiography, DEDR)은 에너지 감산법을 이용하여 신체 내 병변을 감지하는 데 사용 되어 왔다. 본 연구에서는 DEDR을 이용하여 관전압과 부가필터와 같은 물리적 인자를 변화시킴으로써 최적의 뼈와 조직 영상을 획득하고, SRS-78 프로그램으로 예측한 값과 비교하고자 한다. 에너지 감산법을 이용하여 뼈와 조직의 분리된 영상을 획득하기 위하여 다양한 물질의 물리적 인자의 변화에 따른 영상을 구하였다. 연구에 사용된 팬텀은 알루미늄과 polymethyl methacrylate (PMMA)로 구성되었으며, 영상의 최적화는 대조도 대 잡음비 (contrast-to-noise ratio, CNR)로 측정하였다. 실험 결과 50 kVp와 120 kVp 두 영상의 감산 영상이 최적의 뼈와 조직의 분리 영상임을 확인 할 수 있었다. 또한 고 에너지에 10 mm 알루미늄 부가필터를 추가하였을 때, 최적의 뼈와 조직의 분리 효과를 기대 할 수 있었다. 이러한 결과는 실험 전에 SRS-78 프로그램으로 예측한 최적화 조건과 일치함을 알 수 있었다. 본 연구를 통해 관전압이나 부가필터 두께와 같은 물리적 인자를 적절하게 조절한다면 최적의 영상을 얻을 수 있음을 확인하였고, DEDR을 이용하여 원하는 부분만을 표현함으로써 의료영상분야에 기여하고 응용분야를 확장 할 수 있을 것으로 기대한다.

• Imaging Science in Dentistry
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• 제32권3호
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• pp.147-151
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• 2002

Purpose: To compare the standard deviation of gray levels on digital subtracted images obtained by different dental subtraction programs. Materials and Methods: Paired periapical films were taken at the lower premolar and molar areas of the phantoms involving human mandible. The bite registration group used Rinn XCP equipment and bite registration material, based on polyvinyl siloxane, for standardization. The no bite registration group used only Rinn XCP equipment. The periapical film images were digitized at 1200 dpi resolution and 256 gray levels by a flat bed scanner with transparency unit. Dental digital subtraction programs used for this study were Subtractor (Biomedisys Co., Korea) and Emago (Oral Diagnostic Systems, The Netherlands). To measure the similarities between the subtracted images, the standard deviations of the gray levels were obtained using a histogram of subtracted images, which were then analyzed statistically. Results: Subtracted images obtained by using the Emago program without manual selection of corresponding points showed the lowest standard deviation of gray levels (p<0.01). And the standard deviation of gray levels was lower in subtracted images in the group of a bite registration than in the group of no use of bite registration (p < 0.01). Conclusion: Digital radiographic subtraction without manual selection of reference points was found to be a convenient and superior method.

• 대한치주과학회:학술대회논문집
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• 대한치주과학회 2004년도 제44회 종합학술대회 연제초록
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• pp.119-120
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• 2004

• 대한치주과학회:학술대회논문집
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• 대한치주과학회 2001년도 제41회 종합학술대회 연제초록
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• pp.87-88
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• 2001

• Journal of Periodontal and Implant Science
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• 제21권2호
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• pp.188.1-188.1
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• 1991

• Journal of Periodontal and Implant Science
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• 제20권2호
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• pp.158-158
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• 1990