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WDM-PON용 Bi-Di Ferrule 연마기 및 연마기술 개발에 관한 연구
김재열,허상휴,고명석,송경석,유신 한국공작기계학회 2007 한국공작기계학회 추계학술대회논문집 Vol.2007 No.-
WDM-PON(Wavelength Division Multiplexer) was known as solution of ultimate FTTH(Fiber-To-The-Home) in big city and internet network. Optical module part among whole system is the most difficult technologically, it is getting into bottle-neck of development. Quality, all prices are many up to now assignments to be satisfied, it can be said that is early phase. In this treatise I wish to develop WDM-PON Bi-Di Ferrule polishing machine and a polishing technology that use ferule polishing horn in Bi-Di that is an existing technology.
3차원 전산화단층촬영 영상을 이용한 안면 연조직 두께 계측의 임상적 유용성
정호걸,김기덕,한승호,허경석,이제범,박혁,최성호,김종관,박창서 대한구강악안면방사선학회 2006 Imaging Science in Dentistry Vol.36 No.2
Purpose : To evaluate clinical usefulness of facial soft tissue thickness measurement using 3D computed tomographic images. Materials and Methods : One cadaver that had sound facial soft tissues was chosen for the study. The cadaver was scanned with a Helical CT under following scanning protocols about slice thickness and table speed; 3 mm and 3 mm/sec, 5 mm and 5 mm/sec, 7 mm and 7 mm/sec. The acquired data were reconstructed 1.5, 2.5, 3.5 mm reconstruction interval respectively and the images were transferred to a personal computer. Using a program developed to measure facial soft tissue thickness in 3D image, the facial soft tissue thickness was measured. After the ten-time repeation of the measurement for ten times, repeated measure analysis of variance (ANOVA) was adopted to compare and analyze the measurements using the three scanning protocols. Comparison according to the areas was analyzed by Mann-Whitney test. Results : There were no statistically significant intraobserver differences in the measurements of the facial soft tissue thickness using the three scanning protocols (p>0.05). There were no statistically significant differences between measurements in the 3 mm slice thickness and those in the 5 mm, 7 mm slice thickness (p>0.05). There were statistical differences in the 14 of the total 30 measured points in the 5 mm slice thickness and 22 in the 7mm slice thickness. Conclusion : The facial soft tissue thickness measurement using 3D images of 7 mm slice thickness is acceptable clinically, but those of 5 mm slice thickness is recommended for the more accurate measurement.
3차원 전산화단층촬영 영상을 이용한 얼굴 연조직 두께 계측
정호걸,김기덕,한승호,신동원,허경석,이제범,박혁,박창서 대한구강악안면방사선학회 2006 Imaging Science in Dentistry Vol.37 No.1
Purpose : To evaluate accuracy and reliability of program to measure facial soft tissue thickness using 3D computed tomographic images by comparing with direct measurement. Materials and Methods : One cadaver was scanned with a Helical CT with 3 mm slice thickness and 3 mm/sec table speed. The acquired data was reconstructed with 1.5 mm reconstruction interval and the images were transferred to a personal computer. The facial soft tissue thickness were measured using a program developed newly in 3D image. For direct measurement, the cadaver was cut with a bone cutter and then a ruler was placed above the cut side, The procedure was followed by taking pictures of the facial soft tissues with a high-resolution digital camera. Then the measurements were done in the photographic images and repeated for ten times. A repeated measure analysis of variance was adopted to compare and analyze the measurements resulting from the two different methods. Comparison according to the areas was analyzed by Mann-Whitney test. Results : There were no statistically significant differences between the direct measurements and those using the 3D images (p>0.05). There were statistical differences in the measurements on 17 points but all the points except 2 points showed a mean difference of 0.5 mm or less. Conclusion : The developed software program to measure the facial soft tissue thickness using 3D images was so accurate that it allows to measure facial soft tissues thickness more easily in forensic science and anthropology. (Korean J Oral Maxillofac Radiol 2006; 36 : 49-54)
Hu, Kyung-Seok,Choi, Da-Yae,Lee, Won-Jae,Kim, Hee-Jin,Jung, Ui-Won,Kim, Sung-Tae Korean Academy of Periodontology 2012 Journal of Periodontal & Implant Science Vol.42 No.2
Purpose: Special care is necessary to avoid invading important anatomic structures during surgery when presurgical planning is made based on radiographs. However, none of these types of radiography represents a perfect modality. The purpose of this study was to determine the reliability of presurgical planning based on the use of two types of radiographic image (digital panoramic radiography [DPR] and cone-beam computed tomography [CBCT]) by beginner dentists to place implants, and to quantify differences in measurements between radiographic images and real specimens. Methods: Ten fresh cadavers without posterior teeth were used, and twelve practitioners who had no experience of implant surgery performed implant surgery after 10 hours of basic instruction using conventional surgical guide based on CBCT or DPR. Two types of measurement error were evaluated: 1) the presurgical measurement error, defined as that between the presurgical and postsurgical measurements in each modality of radiographic analysis, and 2) the measurement error between postsurgical radiography and the real specimen. Results: The mean presurgical measurement error was significantly smaller for CBCT than for DPR in the maxillary region, whereas it did not differ significantly between the two imaging modalities in the mandibular region. The mean measurement error between radiography and real specimens was significantly smaller for CBCT than for DPR in the maxillary region, but did not differ significantly in the mandibular region. Conclusions: Presurgical planning can be performed safely using DPR in the mandible; however, presurgical planning using CBCT is recommended in the maxilla when a structure in a buccolingual location needs to be evaluated because this imaging modality supplies buccolingual information that cannot be obtained from DPR.
Relationships between Dental Roots and Surrounding Tissues for Orthodontic Miniscrew Installation
Hu, Kyung-Seok,Kang, Min-Kyu,Kim, Tae-Won,Kim, Kyung-Ho,Kim, Hee-Jin The Angle Orthodontist 2009 The Angle orthodontist Vol.79 No.1
<B>Abstract</B><P>Objective: To elucidate relationships between the dental roots and surrounding tissues in order to prevent complications after placement of a miniscrew.</P><P>Materials and Methods: Twenty human mandibles and maxillas were used for this study. In the 200 sections of each mandible and maxilla, nine items were measured to investigate the relationships between the dental roots.</P><P>Results: The interroot distance increased from anterior to posterior teeth and from the cervical line to the root apex in both the maxilla and the mandible. In the maxilla, the greatest interroot distance was between the second premolar and the first molar. In the mandible, the greatest interroot distance was between the first and second molars. The maxillary buccolingual bone width exceeded 10 mm from 7 mm (between canine and first premolar), 5 mm (between second premolar and first molar), and 4 mm (between first and second molars) above the cervical line. The mandibular buccolingual bone width exceeded 10 mm from 7 mm (between second premolar and first molar) and 4 mm (between first and second molars) below the cervical line.</P><P>Conclusions: The safest zone for placement of a miniscrew in the maxilla was between the second premolar and the first molar, from 6 to 8 mm from the cervical line. The safest zone for placement of a miniscrew in the mandible was between the first and second molars, less than 5 mm from the cervical line.</P>