1.Effect of Fracture Gap on Biomechanical Stability of Compression Bone-Plate Fixation System after Bone Fracture Augmentation.
Duk Young JUNG ; Sung Jae LEE ; Seon Chil KIM ; Jong Keon OH
Journal of the Korean Fracture Society 2010;23(2):220-226
PURPOSE: The goal of this study using the biomechanical test was to evaluate the mechanical stability of the bone-plate fixation system according to changes of the fracture gap sizes and widths. MATERIALS AND METHODS: For mechanical test, four types with different fracture models simulating the clinical situations were constructed depending on the gap size (FGS, mm) and the gap width (FGW, %) at the fracture site: 0 mm/0%, 1 mm/100%, 4 mm/100%, 4 mm/50%. For analyzing the effects of fracture gap on the biomechanical stability of the bone-plate fixation system, 4-point bending test was performed under all same conditions. RESULTS: It was found that the fracture gap sizes of 1 and 4 mm decreased mechanical stiffness by about 50~60% or more. Furthermore, even without fracture gap size, 50% or more fracture gap width considerably decreased mechanical stiffness and suggested the possibility of plate damage through strain results. CONCLUSION: Our findings suggested that at least 50% contact of the fracture faces in a fracture surgery would be maintained to increase the mechanical stability of the bone-plate fixation system.
Fractures, Bone
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Sprains and Strains
2.Strain of implants depending on occlusion types in mandibular implant-supported fixed prostheses.
Byoung Sup SOHN ; Seong Joo HEO ; Jai Young KOAK ; Seong Kyun KIM ; Su Young LEE
The Journal of Advanced Prosthodontics 2011;3(1):1-9
PURPOSE: This study investigated the strain of implants using a chewing simulator with strain gauges in mandibular implant-supported fixed prostheses under various dynamic loads. MATERIALS AND METHODS: Three implant-supported 5-unit fixed prostheses were fabricated with three different occlusion types (Group I: Canine protected occlusion, Group II: Unilaterally balanced occlusion, Group III: Bilaterally balanced occlusion). Two strain gauges were attached to each implant abutment. The programmed dynamic loads (0 - 300 N) were applied using a chewing simulator (MTS 858 Mini Bionix II systems, MTS systems corp., Minn, USA) and the strains were monitored. The statistical analyses were performed using the paired t-test and the ANOVA. RESULTS: The mean strain values (MSV) for the working sides were 151.83 microepsilon, 176.23 microepsilon, and 131.07 microepsilon for Group I, Group II, and Group III, respectively. There was a significant difference between Group II and Group III (P < .05). Also, the MSV for non-working side were 58.29 microepsilon, 72.64 microepsilon, and 98.93 microepsilon for Group I, Group II, and Group III, respectively. One was significantly different from the others with a 95% confidence interval (P < .05). CONCLUSION: The MSV for the working side of Groups I and II were significantly different from that for the non-working side (Group I: t = 7.58, Group II: t = 6.25). The MSV for the working side of Group II showed significantly larger than that of Group III (P < .01). Lastly, the MSV for the non-working side of Group III showed significantly larger than those of Group I or Group II (P < .01).
Mastication
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Prostheses and Implants
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Sprains and Strains
3.Influence of microthread design on marginal cortical bone strain developement: A finite element analysis.
Seung Geun CHUN ; Jin Hyun CHO ; Kwang Heon JO
The Journal of Korean Academy of Prosthodontics 2010;48(3):215-223
PURPOSE: The present study was aimed to evaluate the level of cortical bone strain during the placement of an implant. The primary concern was to investigate if the extent of overloading area near the marginal bone could be affected by microthread fabricated at the cervical 1/3 of an implant. MATERIALS AND METHODS: Three dimensional finite element analysis was used to simulate the insertion of 3 implants. Control model was 4.1 x 10 mm implant (Submerged model, Dentis Co,, Daegu, Korea) equipped with a main thread only. Type I was with main thread and microthread, and Type II had similar thread pattern but was of tapered body. A PC-based finite element software (DEFORM 3D ver 5, SFTC, Columbus, OH, USA) was used to calculate a total of 3,600 steps of analysis, which simulated the whole insertion. RESULTS: Results showed that the strain field in the marginal bone within 1 mm of the implant wall was higher than 4,000 micro-strain in the control model. The size of bone overloading was 1-1.5 mm in Type I, and greater than 2 mm in Type II implants. CONCLUSION: These results indicate that the marginal bone may be at the risk of resorption on receiving the implant for all 3 implant models studied. Yet, the risk was greater for Type I and Type II implants, which had microthread at the cervical 1/3.
Finite Element Analysis
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Sprains and Strains
4.Situation of tuberculosis in Viet Nam from an IS 6110 fingerprint analysis of Mycobacterium tuberculosis strains isolated from patients
Journal of Preventive Medicine 1998;8(4):5-13
An IS 6110 fingerprint analysis of 168 Mycobacterium tuberculosis strains isolated from Vietnamese patients has been performed; 67 strains are isolated in the North (N strains), strains isolated in the South comprise 66 strains from tuberculosis patients without AIDS (S strains) and 35 strains from tuberculosis patients with AIDS (A strains). The number of IS 6110 copies per strain varies from 1 to 22 copies. The population of N strains are different from the population of the overall South strains where there was a high prevalence of strains with more than 15 IS copies. That regional difference between the Vietnamese strains was clearly shown by the fingerprint patterns of strains with more than 6 IS. The populations S strains and the A strains have similar fingerprint patterns and 80% of the South strains belong to one big family. In the contrary, a high polymorphism was seen among the N strains
Tuberculosis
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Mycobacterium
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Sprains and Strains
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epedemiology
5.Echocardiographic Measurement of Left Atrial Strain as a Tool for Assessing Left Atrial Function and Geometric Change.
Korean Circulation Journal 2012;42(5):302-303
No abstract available.
Atrial Function, Left
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Sprains and Strains
6.Lisfranc's Joint Injuries.
Sang Rim KIM ; Hyun Sung KANG ; Sung Jin SHIN
Journal of Korean Foot and Ankle Society 2012;16(4):203-209
Lisfranc joint injuries are rare and account for 0.2% of all injuries. The pattern of Lisfranc injuries varies from low-energy ligamentous sprain to high-energy fractures or crushing injuries. Early diagnosis and appropriate treatment of Lisfranc injuries are important to prevent chronic foot pain and dysfunction.
Early Diagnosis
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Foot
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Joints
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Ligaments
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Sprains and Strains
7.Comparative study on stress distribution around internal tapered connection implants according to fit of cement- and screw-retained prostheses.
Mi Young LEE ; Seong Joo HEO ; Eun Jin PARK ; Ji Man PARK
The Journal of Advanced Prosthodontics 2013;5(3):312-318
PURPOSE: The aim of this study was to compare the passivity of implant superstructures by assessing the strain development around the internal tapered connection implants with strain gauges. MATERIALS AND METHODS: A polyurethane resin block in which two implants were embedded served as a measurement model. Two groups of implant restorations utilized cement-retained design and internal surface of the first group was adjusted until premature contact between the restoration and the abutment completely disappeared. In the second group, only nodules detectable to the naked eye were removed. The third group employed screw-retained design and specimens were generated by computer-aided design/computer-aided manufacturing system (n=10). Four strain gauges were fixed on the measurement model mesially and distally to the implants. The strains developed in each strain gauge were recorded during fixation of specimens. To compare the difference among groups, repeated measures 2-factor analysis was performed at a level of significance of alpha=.05. RESULTS: The absolute strain values were measured to analyze the magnitude of strain. The mean absolute strain value ranged from 29.53 to 412.94 microm/m at the different strain gauge locations. According to the result of overall comparison, the cement-retained prosthesis groups exhibited significant difference. No significant difference was detected between milled screw-retained prostheses group and cement-retained prosthesis groups. CONCLUSION: Within the limitations of the study, it was concluded that the cement-retained designs do not always exhibit lower levels of stress than screw-retained designs. The internal adjustment of a cement-retained implant restoration is essential to achieve passive fit.
Eye
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Polyurethanes
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Prostheses and Implants
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Sprains and Strains
8.Improvement in Left Ventricular Systolic Dyssynchrony in Hypertensive Patients After Treatment of Hypertension.
Byung Seok BAE ; Ki Ju KIM ; Jung Gil PARK ; Yeoun Su JUNG ; Han Jun RYU ; Hyun Jae KANG ; Bong Ryeol LEE ; Byung Chun JUNG
Korean Circulation Journal 2011;41(1):16-22
BACKGROUND AND OBJECTIVES: Left ventricular (LV) dyssynchrony has been commonly detected among hypertensive patients with normal LV systolic function and no evidence of congestive heart failure. The purpose of our study was to assess the changes in LV systolic dyssynchrony (SDSLV) among hypertensive patients after antihypertensive treatment, and to determine the relationship between SDSLV and other conventional echocardiographic parameters. SUBJECTS AND METHODS: Forty one hypertensive patients with normal LV ejection fraction were enrolled. By performing a conventional echocardiographic study, the SDSLV was measured as the time difference between the shortest and longest time of the peak myocardial systolic velocities among 12 segments of the basal and mid-levels of the 3 apical views, and radial dyssynchrony of the basal (RDSbase) and mid-levels (RDSmid) measured as the time difference between the earliest and latest peak values on the radial strain curves of each level of the parasternal short-axis views. RESULTS: Compared to baseline after six months of antihypertensive treatment, the SDSLV improved significantly (48.7+/-37.9 ms vs. 29.5+/-34.1 ms, p=0.020). Also the RDSbase and RDSmid improved significantly in respect to the baseline values (129.9+/-136.3 ms vs. 38.8+/-45.4 ms, p=0.002 and 75.2+/-63.8 ms vs. 28.2+/-37.7 ms, respectively, p<0.001). CONCLUSION: The severity of SDSLV improved with antihypertensive treatment, and was associated with the regression of LV mass. Furthermore, it might precede improvement in the mitral inflow pattern, as assessed by conventional echocardiography, so that early detection of the benefit of antihypertensive treatment may be possible.
Echocardiography
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Heart Failure
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Humans
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Hypertension
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Sprains and Strains
9.Molecular Identification of Two Strains of Phellinus sp. by Internal Transcribed Spacer Sequence Analysis.
Mycobiology 2011;39(4):299-300
Two species of cultivated Phellinus sp. were identified as P. baumii by internal transcribed spacer (ITS) sequence analysis. The fruit bodies of the examined strains were similar to those of naturally occurring strains, having a bracket-like form, yellow-to-orange color, and poroid hymenial surfaces. The DNA sequences of ITS region of both strains showed a homology of 99% with ITS1 to ITS2 sequences of P. (Inonotus) baumii strain PB0806.
Base Sequence
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Fruit
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Sequence Analysis
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Sprains and Strains
10.Optimization of orthodontic microimplant thread design.
Kwang Duk KIM ; Won Jae YU ; Hyo Sang PARK ; Hee Moon KYUNG ; Oh Won KWON
Korean Journal of Orthodontics 2011;41(1):25-35
OBJECTIVE: The purpose of this study was to optimize the thread pattern of orthodontic microimplants. METHODS: In search of an optimal thread for orthodontic microimplants, an objective function stability quotient (SQ) was built and solved which will help increase the stability and torsional strength of microimplants while reducing the bone damage during insertion. Selecting the AbsoAnchor SH1312-7 microimplant (Dentos Inc., Daegu, Korea) as a control, and using the thread height (h) and pitch (p) as design parameters, new thread designs with optimal combination of h and p combination were developed. Design soundness of the new threads were examined through insertion strain analyses using 3D finite element simulation, torque test, and clinical test. RESULTS: Solving the function SQ, four new models with optimized thread designs were developed (h200p6, h225p7, h250p8, and h275p8). Finite element analysis has shown that these new designs may cause less bone damage during insertion. The torsional strength of two models h200p6 and h225p7 were significantly higher than the control. On the other hand, clinical test of models h200p6 and h250p8 had similar success rates when compared to the control. CONCLUSIONS: Overall, the new thread designs exhibited better performance than the control which indicated that the optimization methodology may be a useful tool when designing orthodontic microimplant threads.
Finite Element Analysis
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Hand
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Sprains and Strains
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Torque