1.A photoelastic stress analysis of fixed partial dentures with endopore implants according to splinting, contact tightness, and crown length.
Hoe Yeol JEONG ; Min Ho CHOI ; Yu Lee KIM ; Hye Won CHO
The Journal of Korean Academy of Prosthodontics 2004;42(4):425-442
STATEMENT OF PROBLEM: A difficulty in achieving a passive-fitting prosthesis can be overcome by individual crown restoation of multiple implants. But individualized crown has another difficulty in control of contact tightness and stress distribution. PURPOSE: This in vitro study is to evaluate the stress distribution and the magnitude in the supporting tissues around Endopore implants with different crown lengths, interproximal contact tightness, and the splinting effects. MATERIAL & METHODS: Three Endopore implants(4.1*9 mm) were placed in the mandibular posterior edentulous area distal to the canine and photoelastic model was made with PL-2 resin(Measurements Group, Raleigh, USA). Restorations were fabricated in two crown lengths: 9, 13 mm. For non-splinted restorations, individual crowns were fabricated on three custom-milled titanium abutments. After the units were cemented, 4 levels of interproximal contact tightness were evaluated: open, ideal(8 micrometershim stock drags without tearing), medium(40 micrometer), and heavy(80 micrometer). For splinted restorations, 3-unit fixed partial dentures were fabricated. This study was examined under simulated non-loaded and loaded conditions(6.8 kg). Photoelastic stress analysis was carried out to measure the fringe order around the implant supporting structure. RESULTS: 1. When restorations were not splinted, the more interproximal contact tightness was increased among the three implants, the more stress was shown in the cervical region of each implant. When crown length was increased, stresses tended to increase in the apex of implants but there were little differences in stress fringes. 2. When nonsplinted restorations were loaded on the first or third implant, stresses were increased in the apex and cervical region of loaded implant. Regardless of interproximal contact tightness level, stresses were not distributed among the three implants. But with tighter interproximal contact, stresses were increased in the cervical region of loaded first or third implant. 3. When the nonsplinted restorations were not loaded, there were little stresses on the supporting structure of implants, but low level stresses were shown in the splinted restorations even after sectioning and soldering. 4. With splinted restorations, there were little differences in stresses between different crown lengths. When splinted restorations were loaded, stresses were increased slightly on the loaded implant, but relatively even stress distribution occurred among the three implants. CONCLUSIONS: Splinting the crowns of adjacent implants is recommended for Endopore implants under the overloading situation.
Crowns*
;
Denture, Partial, Fixed*
;
Prostheses and Implants
;
Splints*
;
Titanium
2.The effect of denture cleansers on the bond strength and the surface hardness of reline resin to denture base resin.
Kyea Soon KIM ; Hoe Yeol JEONG ; Yu Lee KIM ; Hye Won CHO
The Journal of Korean Academy of Prosthodontics 2003;41(4):493-502
STATEMENT OF PROBLEM: Removable partial denture and complete denture often require denture base relines to improve the fittness against tissue-bearing mucosa because of the gradual change in edentulous ridge contour and resorption of underlyng bony structure. Self-curing hard reline resins offers the immediate and relatively inexpensive means to be recondition the surface of denture base directly. However weak bond between denture base resin and reline material can harbor bacteria, promote staining, or result in complete separation of the two materials. PURPOSE: The purpose of this study was to evaluate the effect of denture cleansers on bond strength and surface hardness of reline resin to denture base resin Denture base resin beams(60.0x15.0x3.0 mm) were made with Lucitone 199. MATERIAL AND METHODS: 10mm section was removed from the center of each specimen. The samples were replaced in the molds and the space of 10mm sections were packed with Tokuso Rebase reline material. The specimens were immersed in denture cleansers(Polident, Cleadent) and were evaluated after 1week, 2weeks, and 4weeks. The bond strength and surface hardness of self-curing hard reline materials to heat-curing denture base resin were measured using an UTM(universal testing machine). RESULTS AND CONCLUSION: 1) There was no significant difference of usage, kind, and denture cleaner by application time on the bonding strength of self-curing hard reline resin to denture base resin. 2) There was no significant difference of usage, kind, and denture cleaner by application time on the surface hardness, but the surface hardness showed decreasing tendency, as the time of immersion was extended 3) The failure modes of the specimens was initially adhesive failure and finally cohesive failure of self-curing hard reline resin.
3.The effects of fabrication of gold cylinder and abutment on the fitness and preload of the prosthesis.
Jum Im HA ; Hoe Yeol JEONG ; Yu Lee KIM ; Hye Won CHO
The Journal of Korean Academy of Prosthodontics 2003;41(4):451-465
STATEMENT OF PROBLEM: Recently various implant components such as premachined gold cylinder, plastic cylinder, gold UCLA abutment and plastic abutment were developed and used clinically without clinical investigation. PURPOSE: The purpose of this study was to evaluate the effects of fabrication of gold cylinder on the fitness and preload of the standard abutment and also the effects of fabrication of UCLA gold abutment on the fitness and stress transfer around the implant fixture. MATERIAL AND METHOD: Three kinds of gold cylinders such as, as-received gold cylinder((Nobel Biocare, Sweden), gold cylinder after casting, and plastic cylinder after casting with type IV gold alloy were tested over the top of the standard abutment. At the same time, three types of abutments such as, gold UCLA abutment before and after casting, and plastic abutment after casting were tested. The cylinder and abutment was secured over the fixture with conventional preload values using an electronic torque controller (Nobel Biocare Sweden). The fitness of the abutment on the fixture and gold cylinder over the standard abutment were measured using the microhardness tester (MXT 70, Matsuzawa, Japan). Preload and the strain values were recorded using the strain balance unit (SB-10, Measurement group, Raleigh, USA) and strain indicator (P-3500, Measurement group, Raleigh, USA) systems. RESULTS AND CONCLUSION: 1. Significant differences were found in the fit between the gold cylinder and plastic cylinder. 2. There were significant differences between the preload of the gold cylinder and that of the plastic cylinder. 3. Significant differences were found in the fit between the gold UCLA abutment and plastic UCLA abutment. 4. There were no significant differences in the stress generated on the supporting structure of the fixture among different cylinder and abutment groups.
4.The effect of combined treatment with cisplatin and histone deacetylase inhibitors on HeLa cells.
Ke Long JIN ; Jeong Yeol PARK ; Eun Joo NOH ; Kwang Lae HOE ; Joo Hak LEE ; Jong Hyeok KIM ; Joo Hyun NAM
Journal of Gynecologic Oncology 2010;21(4):262-268
OBJECTIVE: To investigate the combined effects of cisplatin and the histone deacetylase (HDAC) inhibitors suberoylanilide hydroxamic acid (SAHA) or sirtinol on HeLa cells and assess the mechanism underlying HDAC inhibitor-cisplatin synergy. METHODS: The antineoplastic actions of cisplatin, SAHA and sirtinol, alone and in combination, were evaluated using the tetrazolium dye-based MTT cell proliferation assay, DAPI nuclear staining and cytotoxicity analysis. RESULTS: Exposure to cisplatin, SAHA or sirtinol alone induced a dose-dependent reduction in HeLa cell viability. Combined treatment with cisplatin and SAHA or sirtinol was significantly more cytotoxic than cisplatin alone. Individually, cisplatin, SAHA and sirtinol activated caspase-3 and induced apoptosis, but the effects of combined treatment were greater. Importantly, both HDAC inhibitors dose-dependently inhibited the expression of the antiapoptotic proteins Bcl-2 and x-linked inhibitor of apoptosis protein (XIAP). CONCLUSION: The combination of cisplatin and SAHA or sirtinol had synergistic effect on the HeLa cell viability. This potentiation of cisplatin activity was associated with HDAC inhibitor-mediated down-regulation of Bcl-2 and XIAP. These may result from the relaxation of chromatin by these HDAC inhibitors that increase cisplatin sensitivity by enhancing the accessibility of DNA to cisplatin and transcriptional regulators.
Apoptosis
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Benzamides
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Caspase 3
;
Cell Proliferation
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Chromatin
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Cisplatin
;
DNA
;
Down-Regulation
;
HeLa Cells
;
Histone Deacetylase Inhibitors
;
Histone Deacetylases
;
Histones
;
Humans
;
Hydroxamic Acids
;
Indoles
;
Naphthols
;
Proteins
;
Relaxation
;
Uterine Cervical Neoplasms
;
X-Linked Inhibitor of Apoptosis Protein
5.Scientific Statement for Screening of Coronary Artery Disease in Patients with Ischemic Stroke.
Dongbeom SONG ; Young Dae KIM ; Keun Sik HONG ; Byung Woo YOON ; Byung Chul LEE ; Joung Ho RHA ; Sun Uck KWON ; Hee Joon BAE ; Kyung Ho YU ; Jong Moo PARK ; Kwang Yeol PARK ; Sang Bae KO ; Chang Wan OH ; Jeong Eun KIM ; Ji Hoe HEO
Journal of the Korean Neurological Association 2016;34(2):91-98
Ischemic stroke and myocardial infarction share common risk factors and pathophysiologic mechanisms. Unrecognized coronary artery disease typically occurs in 20-30% of patients with ischemic stroke, and its presence helps to predict the outcome. Coronary artery disease is also an important cause of morbidity and mortality in patients with ischemic stroke. Therefore, applying a screening test for asymptomatic coronary artery disease may be considered in ischemic stroke patients who have a high cardiovascular risk profile. Coronary computed tomography (CT) angiography, myocardial perfusion imaging, or stress echocardiography can be used as a screening test. Coronary CT angiography is recommended in the absence of allergy to contrast media and renal insufficiency.
Angiography
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Contrast Media
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Coronary Artery Disease*
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Coronary Vessels*
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Echocardiography, Stress
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Humans
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Hypersensitivity
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Mass Screening*
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Mortality
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Myocardial Infarction
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Myocardial Perfusion Imaging
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Renal Insufficiency
;
Risk Factors
;
Stroke*