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Stress Analysis of the Occlusal Force on the Mandibular First Premolar
Yoo, Oui-Sik,Chun, Keyoung-Jin,Yoo, Seung-Hyun The Korean Society for Nondestructive Testing 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.
Stress Analysis of the Occlusal Force on the Mandibular First Premolar
Oui-Sik Yoo,Keyoung-Jin Chun,Seung-Hyun Yoo 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.
김중성,임도형,김용화,고영학,이미희,한인호,이성재,Oui Sik Yoo,김한성,박종철 한국정밀공학회 2011 International Journal of Precision Engineering and Vol. No.
A novel porous scaffold designed for application as a bone substitute, with a structure containing three-dimensional (3D)pore channels in a hydroxyapatite (HA) scaffold, was fabricated using a combination of a solid freeform fabrication (SFF)and cast in a mold using freezing casting method. This study was performed to evaluate the physical and biomechanical properties of the HA scaffolds fabricated by SFF and using polymer replication method (PRM), one of the conventional methods. Although the phase composition and porosity of these two scaffolds are similar, their external shape and mechanical property were different. All of the fabricated scaffolds showed similar patterns through X-ray diffraction. The difference between porosities of two HA scaffolds were not statistically significant (P>0.05). However, the average compressive strength of the scaffold fabricated by SFF was 14.6 MPa, and that of the scaffold fabricated using polymer replication was 3.56MPa (P<0.05). It was confirmed that SFF fabrication could have a relatively higher mechanical property than PRM fabrication at the same porosity.
Kang, KwanSu,Jang, Young Woong,Yoo, Oui Sik,Jung, Dukyoung,Lee, Sung-Jae,Lee, Myung Chul,Lim, Dohyung Hindawi 2018 BioMed research international Vol.2018 No.-
<P><B>Introduction</B></P><P> Several ongoing studies aim to improve the survival rate following total knee arthroplasty (TKA), which is an effective orthopedic surgical approach for patients with severely painful knee joint diseases. Among the studied strategies, baseplate rotational arrangement techniques for TKA components have been suggested but have been the subject of only simple reliability evaluations. Therefore, this study sought to evaluate comparatively three different baseplate rotational arrangement techniques that are commonly used in a clinical context.</P><P><B> Materials and Methods</B></P><P> Three-dimensional (3D) finite element (FE) models of the proximal tibia with TKA were developed and analyzed considering three baseplate rotational arrangement techniques (anterior cortex line, tibial tuberosity one-third line, and tibial tuberosity end line) for six activities of daily life (ADLs) among patients undergoing TKA. Mechanical tests based on the ASTM F1800 standard to validate the FE models were then performed using a universal testing machine. To evaluate differences in biomechanical characteristics according to baseplate rotational arrangement technique, the strain and peak von Mises stresses (PVMSs) were assessed.</P><P><B> Results</B></P><P> The accuracy of the FE models used in this study was high (94.7 ± 5.6%). For the tibial tuberosity one-third line rotational arrangement technique, strains ≤ 50 <I>µ</I>strain (the critical bone damage strain, which may affect bone remodeling) accounted for approximately 2.2%–11.3% and PVMSs within the bone cement ranged from 19.4 to 29.2 MPa, in ADLs with high loading conditions. For the tibial tuberosity end line rotational arrangement, strains ≤ 50 <I>µ</I>strain accounted for approximately 2.3%–13.3% and PVMSs within the bone cement ranged from 13.5 to 26.7 MPa. For anterior cortex line rotational arrangement techniques, strains ≤50 <I>µ</I>strain accounted for approximately 10.6%–16.6% and PVMSs within the bone cement ranged from 11.6 to 21.7 MPa.</P><P><B> Conclusion</B></P><P> The results show that the most recently developed frontal cortex line rotational alignment technique is the same or better than the other two rotational alignment techniques in terms of biomechanics. This finding can be, however, dependent on the contact characteristics between the baseplate and the proximal tibia. That is, it is indicated that the optimum baseplate rotational arrangement technique in terms of reducing the incidence of TKA mechanical failure can be achieved by adjusting the characteristics of contact between the baseplate and the proximal tibia.</P>
Jang, Young Woong,Kwon, Soon-Young,Kim, Jung Sung,Yoo, Oui Sik,Lee, Myung Chul,Lim, Dohyung Korean Society for Precision Engineering 2015 International Journal of Precision Engineering and Vol.16 No.10
Artificial composite tibiae have been widely used for mechanical evaluations of total knee arthoplasty (TKA) because of their low variability and wide availability. However, little information is available about whether artificial defects created during production significantly change the distribution of stress and micromotion within composite tibiae during a mechanical evaluation for TKA. The purpose of this study was to determine the effects of artificial defects on alterations in stress distribution and micromotion in composite tibiae during a mechanical evaluation for TKA using finite element (FE) analysis. The results showed that von Mises stresses near the artificial defect were approximately 1.6-fold higher than those on the same regions of composite tibiae without artificial defects. However, the difference in von Mises stresses decreased gradually beginning 3 mm from the center of the artificial defect. Micromotion in composite tibiae with artificial defects was similar to that of tibiae without artificial defects. These findings suggest that stress/strain on the cortical bone surface should be measured at least 3 mm from artificial defect centers but that micromotion is not affected by the artificial defects during a mechanical evaluation for TKA using composite tibiae.
모사경골 홀의 유무에 따른 경골내 응력 분포 패턴 및 기저판과의 Micromotion 차이 분석
장영웅(YoungWoong Jang),이재영(Jae Yeong Lee),염정현(Jung Hyun Yum),유의식(Oui Sik Yoo),김정성(Jung Sung Kim),임도형(Dohyung Lim) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12
The use of artificial bones in implant testing has become popular due to their low variability and ready availability. But the hole, which is created during the production process in located proximal tibia, is apprehended to change stress distribution pattern and make stress concentration. The purpose of this study was to analysis of stress distribution pattern & micromotion deviation between cancellous bone and baseplate according to hole using finite element analysis (FEA). von Mises Stress around the hole at medial, lateral on the cortical surface was measured 63.1%, 66.6% higher than the filled hole model, respectively. But Micromotion between tibia and baseplate was similarly measured in the safe region(0~45μm). These results indicate that mechanical test with artificial bone should be considered the effect of poximal tibia hole.