• Journal of Chest Surgery
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• 제7권2호
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• pp.189-200
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• 1974

The mitral valve replacement with Beall prosthetic valve was performed on three patients, and double valve replacement. aortic and mitral valve, was performed in this department.1) The preoperative studies about the first case were compatible with mitral steno-insufficency.The diseased mitral valve was replaced with the medium sized Beall prosthetic valve under the cardiopulmonary hypass using hypothermic hemodilution technique. The total perfusion time was eighty minutes. Immediate postoperative course was smooth, but this patient was died of asphyxia due to tracheomalacia complicated after tracheostomy 3 months after operation. Autopsy on this patient revealed that no thrombus and no ball variance could be found, and endothelization on the valve cuff was satisfactory. 2) The preoperative studies on the second case were compatible with mitral insufficiency. The diseased mitral valve was replaced with the medium sized Beall prosthetic valve under the cardiopulmonary bypass using hypothermic hemodilution technigue. The total perfusion time was 123 minutes. This patient was discharged in good condition and follow-up study after 16 months revealed the patient had enjoyed healthy life. 3) The preoperative studies about the third case were compatible with aortic insufficiency and mitral stenoinsufficiency. The diseased valves were replaced with type 2 sutureless Magovern aortic valve and the medium sized Beall mitral prosthesis under cardiopulmonary bypass using hypothermic hemodilution technIque and coronary artery perfusion. The total perfusion time was 155 minutes. This patient was discharged in good condition, but thromboembolism was developed 2 months after discharge. 4) The preoperative studies about the fourth case were compatible with mitral insufficiency. The diseased mitral valve was replaced with the medium sized Beall prosthetic valve. The total perfusion time was 132 minutes. The atrioventricular block developed just after operation but converted to normal sinus rhythmn on the third postperative day. The preoperative NYHA functional classification IV was converted to Class 1 or 11 at the time of discharge and this patient enjoyed healthy life. Attendum; The fifth case, nineteen years old male with mital insufficiency underwent Beall valve replacement and his course was uneventful 2 weeks after operation.

• The Journal of Advanced Prosthodontics
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• 제10권4호
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• pp.300-307
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• 2018

PURPOSE. To investigate the fatigue and fracture resistance of computer-aided design and computer-aided manufacturing (CAD/CAM) ceramic molar crowns on dental implants and human teeth. MATERIALS AND METHODS. Molar crowns (n=48; n=8/group) were fabricated of a lithium-disilicate-strengthened lithium aluminosilicate glass ceramic (N). Surfaces were polished (P) or glazed (G). Crowns were tested on human teeth (T) and implant-abutment analogues (I) simulating a chairside (C, crown bonded to abutment) or labside (L, screw channel) procedure for implant groups. Polished/glazed lithium disilicate (E) crowns (n=16) served as reference. Combined thermal cycling and mechanical loading (TC: $3000{\times}5^{\circ}C/3000{\times}55^{\circ}C$; ML: $1.2{\time}10^6$ cycles, 50 N) with antagonistic human molars (groups T) and steatite spheres (groups I) was performed under a chewing simulator. TCML crowns were then analyzed for failures (optical microscopy, SEM) and fracture force was determined. Data were statistically analyzed (Kolmogorow-Smirnov, one-way-ANOVA, post-hoc Bonferroni, ${\alpha}=.05$). RESULTS. All crowns survived TCML and showed small traces of wear. In human teeth groups, fracture forces of N crowns varied between $1214{\pm}293N$ (NPT) and $1324{\pm}498N$ (NGT), differing significantly ($P{\leq}.003$) from the polished reference EPT ($2044{\pm}302N$). Fracture forces in implant groups varied between $934{\pm}154N$ (NGI_L) and $1782{\pm}153N$ (NPI_C), providing higher values for the respective chairside crowns. Differences between polishing and glazing were not significant ($P{\geq}.066$) between crowns of identical materials and abutment support. CONCLUSION. Fracture resistance was influenced by the ceramic material, and partly by the tooth or implant situation and the clinical procedure (chairside/labside). Type of surface finish (polishing/glazing) had no significant influence. Clinical survival of the new glass ceramic may be comparable to lithium disilicate.

• The Journal of Advanced Prosthodontics
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• 제10권4호
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• pp.308-314
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• 2018

PURPOSE. Plasma activation of hydrophobic zirconia surfaces might be suitable to improve the bond strength of luting materials. The aim of this study was to analyze the influence of nonthermal argon-plasma on the shear bond strength (SBS) between zirconia and different combinations of 10-MDP adhesive systems and luting composites after artificial aging. MATERIALS AND METHODS. Two hundred forty Y-TZP specimens were ground automatically with $165{\mu}m$ grit and water cooling. Half of the specimens received surface activation with nonthermal argon-plasma. The specimens were evenly distributed into three groups according to the adhesive systems ([Futurabond U, Futurabond M, Futurabond M + DCA], VOCO GmbH, Germany, Cuxhaven) and into further two subgroups according to the luting materials ([Bifix SE, Bifix QM], VOCO GmbH). Each specimen underwent artificial aging by thermocycling and water storage. SBS was measured in a universal testing machine. Statistical analysis was performed using ANOVA and $Scheff{\grave{e}}$ procedure with the level of significance set to 0.05. RESULTS. Surface activation with nonthermal plasma did not improve the bond strength between zirconia and the tested combinations of adhesive systems and luting materials. The plasma-activation trended to reveal higher bond strength if the self-etch luting material (Bifix SE) was used, irrespective of the adhesive system. CONCLUSION. Plasma-activation seems to be suitable to improve bond strength between zirconia and self-etch resin materials. However, further research is necessary to identify the influence of varying plasma-parameters.

• The Journal of Advanced Prosthodontics
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• 제10권4호
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• pp.315-320
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• 2018

PURPOSE. Fractures, occlusal adjustments, or marginal corrections after removing excess composite cements result in rough surfaces of all-ceramic FPDs. These have to be polished to prevent damage of the surrounding tissues. The aim of this study was to evaluate the roughness of zirconia, silicate-ceramic, and composite after polish with different systems for intraoral use. MATERIALS AND METHODS. Each set of 50 plates was made of zirconia, silicate-ceramic, and composite. All plates were ground automatically and were divided into 15 groups according to the treatment. Groups Zgrit, Sgrit, and Cgrit received no further treatment. Groups Zlab and Slab received glaze-baking, and group Clab was polished with a polishing device. In the experimental groups Zv, Sv, Cv, Zk, Sk, Ck, Zb, Sb, and Cb, the specimens were polished with ceramic-polishing systems "v", "k", and "b" for intraoral use. Roughness was measured using profilometry. Statistical analysis was performed with ANOVA and $Scheff{\acute{e}}$-procedure with the level of significance set at P=.05. RESULTS. All systems reduced the roughness of zirconia, but the differences from the controls Zgrit and Zlab were not statistically significant (P>.907). Roughness of silicate ceramic was reduced only in group Sv, but it did not differ significantly from both controls (P>.580). Groups Cv, Ck, and Cb had a significantly rougher surface than that of group Clab (P<.003). CONCLUSION. Ceramic materials can be polished with the tested systems. Polishing of interface areas between ceramic and composite material should be performed with polishing systems for zirconia first, followed by systems for veneering materials and for composite materials.

• 대한치과의사협회지
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• 제47권9호
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• pp.585-595
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• 2009

Purpose : The aim of this study was to compare surgical complications between simple implant placement and implant placement combined with complicated surgical procedures. We also evaluated prosthetic complications according to the specific types of prosthesis. Material and Method : A retrospective analysis of dental chart of patients who was performed implant therapy during the period from June 2003 to December 2005 was carried out. This study was performed on 408 patients (208 male, 200 female). In addition, 1671 implants were performed. Based on their medical record and radiographs, the authors evaluated surgical and prosthetic complications, surgical procedures accompanied at the time of implant, risk factors of implant failure etc. Result : Surgical complications were developed on 358 implants(21.4% on total placed implants) and wound dehiscence was most prevalent complication. On maxillary posterior area, surgical complications developed more frequently on implants with major surgery and showed a significant difference. And complication rate of implants accompanied with GBR was higher than that of simple implants placement and also showed significant difference. The implant supported prosthesis showed no statistical difference in the occurrence of complications according to the types of prosthesis, and food retention was the most common post-prosthetic complication. Also we speculated that length and width of implant showed significant correlation to the failure of implant primary osseointegration. Conclusion : Based on the result, clinician should provide more careful maintenance for patients with implant placement accompanied by complicated surgical procedure. And periodic maintenance for the patient is requested for long-term survival of implant therapy.

• The Journal of Advanced Prosthodontics
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• 제9권4호
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• pp.294-301
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• 2017

PURPOSE. Temperature increase of $5.5^{\circ}C$ can cause damage or necrosis of the pulp. Increasing temperature can be caused not only by mechanical factors, e.g. grinding, but also by exothermic polymerization reactions of resin materials. The aim of this study was to evaluate influences of the form material on the intrapulpal temperature during the polymerization of different self-curing resin materials for temporary restorations. MATERIALS AND METHODS. 30 provisonal bridges were made of 5 resin materials: Prevision Temp (Pre), Protemp 4 (Pro), Luxatemp Star (Lux), Structure 3 (Str) and an experimental material (Exp). Moulds made of alginate (A) and of silicone (S) and vacuum formed moulds (V) were used to build 10 bridges each on a special experimental setup. The intrapulpal temperatures of three abutment teeth (a canine, a premolar, and a molar,) were measured during the polymerization every second under isothermal conditions. Comparisons of the maximum temperature ($T_{Max}$) and the time until the maximum temperature ($t_{TMax}$) were performed using ANOVA and Tukey Test. RESULTS. Using alginate as the mould material resulted in a cooling effect for every resin material. Using the vacuum formed mould, $T_{Max}$ increased significantly compared to alginate (P<.001) and silicone (P<.001). In groups Lux, Pro, and Pre, $t_{TMax}$ increased when the vacuum formed moulds were used. In groups Exp and Str, there was no influence of the mould material on $t_{TMax}$. CONCLUSION. All of the mould materials are suitable for clinical use if the intraoral application time does not exceed the manufacturer's instructions for the resin materials.

• The Journal of Advanced Prosthodontics
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• 제12권1호
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• pp.1-8
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• 2020

PURPOSE. To investigate the influence of crown material (lithium-disilicate, 3Y-TZP zirconia) and abutment type (rigid implant, resin tooth with artificial periodontium) on wear performance of their antagonist teeth and adjacent teeth. MATERIALS AND METHODS. A mandibular left first molar (#36) with adjacent human teeth (mandibular left second premolar: #35, mandibular left second molar: #37) and antagonistic human teeth (maxillary left second premolar: #25, maxillary left first molar: #26, maxillary left second molar: #27) was prepared simulating a section of the jaw. Samples were made with extracted human molars (Reference), crowned implants (Implant), or crowned resin tooth analogues (Tooth). Crowns (tooth #36; n = 16/material) were milled from lithium-disilicate (Li, IPS e.max CAD) or 3Y-TZP zirconia (Zr, IPS e.max ZirCAD, both Ivoclar Vivadent). Thermal cycling and mechanical loading (TCML) in the chewing simulator were applied simulating 15 years of clinical service. Wear traces were analyzed (frequency [n], depth [㎛]) and evaluated using scanning electron pictures. Wear results were compared by one-way-ANOVA and post-hoc-Bonferroni (α = 0.05). RESULTS. After TCML, no visible wear traces were found on Zr. Li showed more wear traces (n = 30-31) than the reference (n = 21). Antagonistic teeth #26 showed more wear traces in contact to both ceramics (n = 27-29) than to the reference (n = 21). Strong wear traces (> 350 ㎛) on antagonists and their adjacent teeth were found only in crowned groups. Abutment type influenced number and depth of wear facets on the antagonistic and adjacent teeth. CONCLUSION. The clinically relevant model with human antagonistic and adjacent teeth allowed for a limited comparison of the wear situation. The total number of wear traces and strong wear on crowns, antagonistic and adjacent teeth were influenced by crown material.

• Journal of Chest Surgery
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• 제16권4호
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• pp.498-505
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• 1983

It has been over 20 years since successful operations of Cardiac valves at the Department of Thoracic and Cardiovascular surgery, college of medicine, Yonsei University. About six hundreds of patients with severely symptomatic valvular heart disease have had valve operations with complete loss or sharp decrease in their cardiac symptoms since 1956. As the number of cardiac patient increases, reoperation on valves assumes greater importance. To define the group of patients undergoing reoperations on valves and the factors influencing their survival, we have reviewed our experiences of the reoperation on valves at the Yonsei University, Severance Hospital. This is a report of 29 cases which was undergone secondary or more surgery for valvular heart disease from 1966 to 1983. The primary operations includes 159 cases of open heart surgery from 1966 to 1975 and 476 cases from 1976 to march, 1983. The secondary operations are classified into groups of secondary valvuloplasty or valvotomy [8 cases], prosthetic valve replacement following valvuloplasty or valvotomy [14 cases] and prosthetic valve rereplacement [2 case] for such as calcification, degeneration and perforation of the cusps and paravalvular leakage, of the bioprosthetic valves. The leading indication for reoperation of mitral valve was restenosis or stenoinsufficiency, The indications of aortic valve replacement was active bacterial endocarditis, medically uncontrollable prosthetic endocarditis or paravalvular leakage. Overall death rate of the reoperation was 17.4% [5 death among the 29 patients] and the leading causes of death were myocardial failure, arrhythmia, cerebral embolism, acute renal failure due to low output syndrome. And it was followed by sepsis associated with active prosthetic endocarditis. The death rate of reoperation was 4.3% in the elective cases except urgent cases and the death rate of overall cardiac valve except reoperation cases was 4.1% in the last two years. Although the general mortality of reoperation was high, both mortality rates were comparable except emergency cases due to urgent preoperative patient’s condition.

• The Journal of Advanced Prosthodontics
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• 제4권3호
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• pp.127-133
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• 2012

PURPOSE. Many dentists use desensitizing agents to prevent hypersensitivity. This study compared and evaluated the effect of two desensitizing agents on the retention of cast crowns when cemented with various luting agents. MATERIALS AND METHODS. Ninety freshly extracted human molars were prepared with flat occlusal surface, 6 degree taper and approximately 4 mm axial length. The prepared specimens were divided into 3 groups and each group is further divided into 3 subgroups. Desensitizing agents used were GC Tooth Mousse and $GLUMA^{(R)}$ desensitizer. Cementing agents used were zinc phosphate, glass ionomer and resin modified glass ionomer cement. Individual crowns with loop were made from base metal alloy. Desensitizing agents were applied before cementation of crowns except for control group. Under tensional force the crowns were removed using an automated universal testing machine. Statistical analysis included one-way ANOVA followed by Turkey-Kramer post hoc test at a preset alpha of 0.05. RESULTS. Resin modified glass ionomer cement exhibited the highest retentive strength and all dentin treatments resulted in significantly different retentive values (In Kg.): GLUMA ($49.02{\pm}3.32$) > Control ($48.61{\pm}3.54$) > Tooth mousse ($48.34{\pm}2.94$). Retentive strength for glass ionomer cement were GLUMA ($41.14{\pm}2.42$) > Tooth mousse ($40.32{\pm}3.89$) > Control ($39.09{\pm}2.80$). For zinc phosphate cement the retentive strength were lowest GLUMA ($27.92{\pm}3.20$) > Control ($27.69{\pm}3.39$) > Tooth mousse ($25.27{\pm}4.60$). CONCLUSION. The use of $GLUMA^{(R)}$ desensitizer has no effect on crown retention. GC Tooth Mousse does not affect the retentive ability of glass ionomer and resin modified glass ionomer cement, but it decreases the retentive ability of zinc phosphate cement.

• The Journal of Advanced Prosthodontics
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• 제6권6호
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• pp.474-482
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• 2014

PURPOSE. To assess removable prosthetic restoration tolerance according to the patient section of the short form of the Gagging Problem Assessment Questionnaire (GPA-pa SF) and the influence of gender, education level and prosthesis type and denture-related mucosal irritation on the GPA-pa SF scores before treatment and over a period of two months after prosthesis insertion. MATERIALS AND METHODS. 130 participants who required removable prosthesis were surveyed with a standard form that included questions regarding age, gender, education level, dental attendance, and prosthetic restoration type. Participants answered the GPA-pa SF before restoration (T0) and 1 day (T1), 2 days (T2), 15 days (T3), 1 month (T4), and 2 months (T5) after prosthesis insertion. RESULTS. Of the 130 participants, 110 participants completed the prosthetic restoration procedure, but only 93 of these were able to use the prosthesis over the two-month period. The mean GPA-pa SF score obtained at T0 was higher than the scores obtained at the other periods in the total of the sample. Significant difference was present between mean scores obtained at T0-T1 and T2-T3 than scores obtained at other periods (P<.05). Female participants and participants with denture-related mucosal irritation had higher GPA-pa SF scores at all time points analysed. Significant difference was present between mean GPA-pa SF scores obtained at T2-T3 than scores obtained at other periods for females and participants with denture-related mucosal irritation (P<.05). Education level and prosthesis type did not significantly influence the GPA-pa SF score at any time point analysed (P>.05). CONCLUSION. GPA-pa SF scores were higher before the restoration procedure began, and decreased over time with the use of prosthesis. Gender and denture-related mucosal irritation affected the GPA-pa SF scores.