돼지 하악골의 micro-CT 영상에서 추출한 3차원 골미세구조와 골강도 사이의 상관관계

허경회,박무순,이원진,허민석,이삼선,최순철 대한구강악안면방사선학회 2005 Imaging Science in Dentistry Vol.35 No.3

Purpose : To investigate the relationship between three-dimensional (3D) bone imaging parameters and trabecular strength in the mandible. Materials and Methods : Bone specimens were obtained from the mandibles of five male pigs weighing around 110 kg each. Of those, 43 samples were selected for 3D analysis and measured by micro-computed tomography. The five morphometric parameters were trabecular thickness (Tb.Th), bone specific surface (BS/BV), percent bone volume (BV/TV), structure model index (SMI) and degree of anisotropy (DA). Through destructive mechanical testing, strength parameters were obtained. Results : BV/TV, SMI, BS/BV, and Tb.Th showed significant correlations with strength parameters. DA did not show any correlation with the other parameters. In multiple linear regression analysis, BV/TV alone explained 43% of the variance in Young’s modulus. By stepwise inclusion of SMI, the variance in the Young’s modulus was better explained up to 52%. Conclusions : Predicting trabecular strength in the mandible through architectural analysis would be possible. Further study is needed to establish the tendency and variety of trabecular architecture and strength according to the locations within the mandible.

의원성 사고로 발생한 타액선염 : 증례보고

김현우,허경회,이원진,허민석,이삼선,최순철 대한구강악안면방사선학회 2004 Imaging Science in Dentistry Vol.34 No.2

A case of sialadenitis is presented in a patient with painful swelling of the right mouth floor. The condition was caused by trauma on the right mouth floor during dental treatment, which had happened 15 days before admission. On aspiration, mucous secretion was found and ultrasonography showed obstruction of duct. Histopathological studies and surgical investigation established a definite diagnosis of obstructive sialadenitis caused by ductal laceration. As surgical treatment sialodochoplasty was selected. The case and relevant considerations are discussed.

결합조직형성 법랑모세포종의 방사선학적 소견 : 증례보고 3례

최다혜,허경회,문제운,이원진,허민석,이삼선,최순철,박관수 대한구강악안면방사선학회 2006 Imaging Science in Dentistry Vol.37 No.1

Desmoplastic ameloblastoma is a rare histologic variant of ameloblastoma. It shows important differences in anatomic distribution, histologic appearance, and radiographic findings compared with the general type of ameloblastoma. It is histologically characterized by an abundance of densely collagenous stroma and radiographically a mixed radiolucent-radiopaque lesion. We present three cases of desmoplastic ameloblastoma. All the patients complained on buccal swelling with or without pain and the sites of occurrence were the anterior and the premolar region. Plain radiographs showed mixed radiopaque-radiolucent lesion with ill-defined or diffuse sclerotic margin and no external root resorption. Additionally, CT scans revealed buccal expansion and relatively well-defined margin of the lesions. The clinical and radiographic features of the presented cases were compared with those of the desmoplastic ameloblastoma in the previous literatures. (Korean J Oral Maxillofac Radiol 2006; 36 : 63-8)

방사선사진에서의 골질과 임상적으로 평가한 골질 분류의 상관관계

김현우,허경회,박관수,김정화,이원진,허민석,이삼선,최순철 대한구강악안면방사선학회 2006 Imaging Science in Dentistry Vol.37 No.1

Purpose : To investigate the validity of digital image processing on panoramic radiographs in estimating bone quality before endosseous dental implant installation by correlating bone quality in radiographic images with clinical bone quality classification. Materials and Methods : An experienced surgeon assessed and classified bone quality for implant sites with tactile sensation at the time of implant placement. Including fractal dimension eighteen morphologic features of trabecular pattern were examined in each anatomical sites on panoramic radiographs. Finally bone quality of 67 implant sites were evaluated in 42 patients. Results : Pearson correlation analysis showed that three morphologic parameters had weak linear negative correlation with clinical bone quality classification showing correlation coefficients of -0.276, -0.280, and -0.289, respectively (p<0.05). And other three morphologic parameters had obvious linear negative correlation with clinical bone quality classification showing correlation coefficients of -0.346, -0.488, and -0.343 respectively (p<0.05). Fractal dimension also had a linear correlation with clinical bone quality classification with correlation coefficients -0.506 significantly (p<0.05). Conclusion : This study suggests that fractal and morphometric analysis using digital panoramic radiographs can be used to evaluate bone quality for implant recipient sites. (Korean J Oral Maxillofac Radiol 2006; 36 : 25-32)

구강외과 수술용 스텐트 기반 영상유도 수술 시스템의 개발

이우진,김대승,이원진,이삼선,최순철,허민석,허경회,김명진,이지호 대한구강악안면방사선학회 2009 Imaging Science in Dentistry Vol.39 No.3

Purpose : The purpose of this study was to develop a stent-based image guided surgery system and to apply it to oral and maxillofacial surgeries for anatomically complex sites. Materials and Methods : We devised a patient-specific stent for patient-to-image registration and navigation. Threedimensional positions of the reference probe and the tool probe were tracked by an optical camera system and the relative position of the handpiece drill tip to the reference probe was monitored continuously on the monitor of a PC. Using 8 landmarks for measuring accuracy, the spatial discrepancy between CT image coordinate and physical coordinate was calculated for testing the normality. Results : The accuracy over 8 anatomical landmarks showed an overall mean of 0.56±0.16 mm. The developed system was applied to a surgery for a vertical alveolar bone augmentation in right mandibular posterior area and possible interior alveolar nerve injury case of an impacted third molar. The developed system provided continuous monitoring of invisible anatomical structures during operation and 3D information for operation sites. The clinical challenge showed sufficient accuracy and availability of anatomically complex operation sites. Conclusion : The developed system showed sufficient accuracy and availability in oral and maxillofacial surgeries for anatomically complex sites. (Korean J Oral Maxillofac Radiol 2009; 39 : 149-56)

단면 CT 영상을 이용한 무치악 하악 대구치부 잔존골의 형태 분석

이설미,허경회,이원진,허민석,이삼선,강태인,최순철 대한구강악안면방사선학회 2007 Imaging Science in Dentistry Vol.37 No.3

Purpose : The purpose of this study was to evaluate the morphologic features of posterior edentulous mandible for Korean patients using cross-sectional CT images. Materials and Methods : Computed tomographic cross-sectional views taken in 2004 and 2005 at Seoul National University Dental Hospital were analyzed by an oral and maxillofacial radiologist. Four indices were measured to meet the purpose of this study: 1) the horizontal distance between the alveolar crest and mandibular canal (Type), 2) the angle of the mandibular long axis (Angle), 3) the bucco-lingual location of mandibular canal, and 4) the depth of the submandibular fossa. The averages and standard deviations of the measurements were compared according to the location (the first and second molar area) and sex of the patients. Results : Statistically significant difference was found in Type, Angle, and submandibular fossa depth between the first and second molar area (P<0.05). However, there was no significant difference between men and women in any of the measured indices. Most of the mandibular canals were located in lingual side of posterior mandible. Conclusion : More care should be taken when an implant is installed on the mandibular second molar area.

CT사진을 이용한 한국인의 C형 치근관의 분포에 대한 연구

전록원,허경회,이원진,허민석,이삼선,최순철 대한구강악안면방사선학회 2009 Imaging Science in Dentistry Vol.39 No.2

Purpose : To investigate the incidence and prevalence of C-shaped root canal using computed tomographic images of head and neck in Korean population. Materials and Methods : Regardless of each examination purpose, randomly selected 268 examples which have serial axial computed tomographic images with 8 normal molars in maxilla and mandible were selected and investigated. Defined C-shaped root canal and we could get 82 proper image examples in view of this definition. These were detected and investigated of incidence and prevalence of C-shaped root canal. Results : C-shaped root canals were found in 82 examples among 268 (30.6%) and 147 teeth. They were only found on molar area, and the highest incidence was 37.41% of left mandibular second molars, and the lowest was 2.04%of right maxillary second molars. On prevalence of tooth position, mandibular second molar was the highest, 65% of C-shaped root canal teeth and maxillary second molar was 6% the lowest. Conclusion : 31% of randomly selected CT images no considering check-up reason have C-shaped root canals. The C-shaped root canals of mandibular second molar are found most frequently and they are also detectable on maxilla. On Korean population, C-shaped root canals are one of conditions that have to concern with dental treatment for it appears at a high prevalence relatively.

다발성 연조직 종괴를 동반한 급성 림프구성 백혈병의 증례 보고

장정용,허경회,이원진,허민석,이삼선,최순철 대한구강악안면방사선학회 2005 Imaging Science in Dentistry Vol.35 No.2

A 15-year-old patient, who had been diagnosed and treated as Burkitt cell type acute lymphoblastic leukemia (ALLL3) already, visited our department. He complained of gingival enlargement and loosening teeth 1 month ago. The clinical examination revealed anterior open bite, gingival enlargement, and nontender swelling particularly in molar regions of both jaws. Deep periodontal pockets and severe mobility was shown on most of the teeth. The panoramic radiographs showed severe bone destruction and extrusion of the molars. The contrast enhanced CT showed multiple enhanced mass and bone marrow obliteration in both jaws. Chemotherapy was done and the swelling was subsided at 1 month later. In conclusion, radiologic findings of leukemia with soft tissue mass, known as chloroma or granulocytic sarcoma, mimic those of lymphoma, so blood test may be needed for the final diagnosis.

디지털 및 일반 측방두부규격방사선사진에서 측정 방법에 따른 계측치의 비교

김미자,허경회,이원진,허민석,이삼선,이진구,안병근,최순철 대한구강악안면방사선학회 2005 Imaging Science in Dentistry Vol.35 No.1

Purpose : To compare cephalometric measurement between measuring methods in digital and conventional lateral cephalometric radiograph. Materials and Methods : Twenty digital and conventional lateral cephalometric radiographs were selected. In digital group, cephalometric measurements were performed manually using hardcopies and automatically using VCeph^(TM) program on the monitor. In conventional group, the same measurements were performed manually on conventional films, and for automatic measurement conventional films were digitized by scanner. All measurements were performed twice by 4 observers, and 24 cephalometric variables were calculated and the time spent for each measurement was recorded. The differences in measurements data and the time spent for each measurement were compared within each group. Intra-observer and inter-observer comparisons were performed. Results : In both groups, no statistically significant difference between manual and automatic measurements was observed and most of the variables didn’t show statistically significant differences between methods. The observer with less experience tended to show statistically significant differences of measurements between methods, and differences from other observers. The differences of measurements between methods in digital group were lesser than those of conventional group with statistical significance in 8 variables out of 24. With automatic method and in digital group, the spent time was shorter. Conclusion : With direct digital radiograph, automatic method using manually idenitified landmarks can be preferable in cephalometric analysis.

돼지 하악 과두의 해면골에서 유한요소분석법으로 예측한 방향에 따른 탄성율과 3차원 골 미세지표 간의 상관관계

박관수,이삼선,허경회,이원진,허민석,최순철 대한구강악안면방사선학회 2008 Imaging Science in Dentistry Vol.38 No.2

Purpose : To investigate the relationship between 3D bone architectural parameters and direction-related elastic moduli of cancellous bone of mandibular condyle. Materials and Methods : Two micro-pigs (Micro-pig^(R), PWG Genetics Korea) were used. Each pig was about 12 months old and weighing around 44 kg. 31 cylindrical bone specimen were obtained from cancellous bone of condyles for 3D analysis and measured by micro-computed tomography. Six parameters were trabecular thickness (Tb.Th), bone specific surface (BS/BV), percent bone volume (BV/TV), structure model index (SMI), degree of anisotropy (DA) and 3-dimensional fractal dimension (3DFD). Elastic moduli of three orthogonal directions (superiorinferior (SI), medial-lateral (ML), andterior-posterior (AP) direction) were calculated through finite element analysis. Results : Elastic modulus of superior-inferior direction was higher than those of other directions. Elastic moduli of 3 orthogonal directions showed different correlation with 3D architectural parameters. Elastic moduli of SI and ML directions showed significant strong to moderate correlation with BV/TV, SMI and 3DFD. Conclusion : Elastic modulus of cancellous bone of pig mandibular condyle was highest in the SI direction and it was supposed that the change into plate-like structure of trabeculae was mainly affected by increase of trabeculae of SI and ML directions.