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Stress Analysis of the Occlusal Force on the Mandibular First Premolar
유의식,전경진,유승현 한국비파괴검사학회 2009 한국비파괴검사학회지 Vol.29 No.3
The occlusal force of the tooth leads to loss of tooth tissue owing to attrition and abrasion, and may cause abfraction and pathological change of the dentin. Thus, we developed finite element models, examined them by applying ordinary occlusal force, and analyzed the stress distribution. Specimens used were mandibular first premolars from 15 Korean males and 13 females and were made into finite element models from medical images that were obtained using a Micro-CT. We have found that the irregular feature of the tooth is not only useful to masticating and pronouncing as well known, but it is also suitable for protecting inner tissue by dispersing stress and delivering proper pressure to periodontal tissue to continue a physiological action. Also, image analysis could let us know the factor that is the cause of a disorder due to stress concentration in the cervical line. These results are expected to support the field of dental treatment planning, operating procedure and clinical trial, and the advance of technical expertise to develop implants and dentures.
Morphological Study and Stress Analysis of Korean Mandibular Second Premolar
전경진,유의식,원예연,이종엽 한국정밀공학회 2009 International Journal of Precision Engineering and Vol. No.
Tooth morphology has an important role in esthetical characteristics, functional performance and physiological action. Mandibular second premolars among teeth were taken for a close investigation with a micro-CT for a nondestructive measurement. Thus, the shape of the tooth was classified into a few partitions and measured by setting the reference axis to express internal and external morphology numerically. About a thousand tomographic images were obtained for each specimen and were reconstructed to a three-dimensional form. The lengths and widths of each dental tissue were measured from the three-dimensional form. In this tooth type, the width of dentine is comparatively larger than that of enamel, and buccal tissue of the crown is thicker than lingual tissue. Hence, buccal tissue could afford to withstand against exterior impact or stimulus. Finite element models were drawn up, applied with an ordinary occlusal force and analyzed to get the stress distribution. Thus it was shown that the irregular feature of the tooth is not useful only to masticating and pronouncing as well known, but that it is also suitable for protecting inner tissue by dispersing stress and delivering proper pressure to periodontal tissue to continue a physiological action. These results could be used for development of dental implants and clinical trials.
반치환 슬관절의 설계 평가를 위한 굴곡각도에 따른 곡률반경과 접촉응력의 상관도 분석
이용경,유의식,김재원,임도형,정태곤,김정성,Lee, YongKyung,Yoo, OuiSik,Kim, JaeWon,Lim, Dohyung,Jung, TaeGon,Kim, JungSung 대한의용생체공학회 2016 의공학회지 Vol.37 No.6
Conformity between the femoral component and tibial insert within the knee replacement may be measured in frontal or sagittal view, and shows differences in the curvature radius of the femoral component depending on the flexion angle, i.e., curvature radius has a complex effect on contact stress. Therefore, it is essential to confirm how the curvature radius effects contact stress, and provide an important variable to reduce contact stress. This study correlated contact stress with curvature radius measured in frontal and the sagittal views and confirmed the effect of curvature radius for assessment of the Newly Designed Unicompartment Knee Replacement (NDUKR). Finite element models were constructed for NDUKR and $Zimmer^{(R)}$ Unicompartment High Flex Knee Replacement system (ZUKR), incorporating the curvature radius as measured in either frontal or sagittal view. The femoral component had 1200N of compressive load applied approximately 1.65xbody weight. Contact stress was predicted at flexion angles $0^{\circ}C$, $30^{\circ}C$, $60^{\circ}C$, $90^{\circ}C$ and $120^{\circ}C$, for NDUKR: 42, 47.7, 47.7, 51.2, and 54.1 MPa, and ZUKR: 41.2, 49.5, 53.2, 54.3, and 57.4 MPa, respectively. Correlation analysis showed the influence of curvature radius measured from the sagittal view was larger than for frontal view.