• The Journal of Korean Academy of Prosthodontics
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• v.29 no.1
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• pp.13-22
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• 1991

This study investigated the effects of surface treatment on the tensile bond strength of resinbonded prosthesis. The Rexillium III specimens were treated with $50{\mu}m\;Al_2O_3$ blasting. Type IV gold alloy specimens were treated with $400^{\circ}C$ heating and tin plating method. All specimens were bonded with MBAS composite resin cement and followed by immersion test into the $37^{\circ}C$ water bath for 7 days. The specimens were debonded in tension with an Instron machine and observed with SEM. The modes of failure were recorded also. The following conclusions were obtained : 1. The tensile bond strength decreased in following order. $50{\mu}m\;Al_2O_3$ basted Resillium III group, Type IV gold alloy group treated with $400^{\circ}C$ heat and tin plating type IV gold alloy group, and statistical significant differences were observed(p<0.05). 2. The tensile bond strength decreased in all groups after 7 days immersion test, but statistical significant differences were observed in Rexillium III specimens only. 3. The sharp and irregular surface were observed in Rexillium III, but $400^{\circ}C$ heat treated and tin plated groups had round and broad surface in SEM. 4. The models of bond failure were cohesive-adhesive failure mainly.

• Journal of Periodontal and Implant Science
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• v.49 no.5
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• pp.287-298
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• 2019

Purpose: The aim of this retrospective study was to determine the prevalence of early implant failure using a single implant system and to identify the factors contributing to early implant failure. Methods: Patients who received implant treatment with a single implant system ($Luna^{(R)}$, Shinhung, Seoul, Korea) at Dankook University Dental Hospital from 2015 to 2017 were enrolled. The following data were collected for analysis: sex and age of the patient, seniority of the surgeon, diameter and length of the implant, position in the dental arch, access approach for sinus-floor elevation, and type of guided bone regeneration (GBR) procedure. The effect of each predictor was evaluated using the crude hazard ratio and the adjusted hazard ratio (aHR) in univariate and multivariate Cox regression analyses, respectively. Results: This study analyzed 1,031 implants in 409 patients, who comprised 169 females and 240 males with a median age of 54 years (interquartile range [IQR], 47-61 years) and were followed up for a median of 7.2 months (IQR, 5.6-9.9 months) after implant placement. Thirty-five implants were removed prior to final prosthesis delivery, and the cumulative survival rate in the early phase at the implant level was 95.6%. Multivariate regression analysis revealed that seniority of the surgeon (residents: aHR=2.86; 95% confidence interval [CI], 1.37-5.94) and the jaw in which the implant was placed (mandible: aHR=2.31; 95% CI, 1.12-4.76) exerted statistically significant effects on early implant failure after adjusting for sex, age, dimensions of the implant, and type of GBR procedure (preoperative and/or simultaneous) (P<0.05). Conclusions: Prospective studies are warranted to further elucidate the factors contributing to early implant failure. In the meantime, surgeons should receive appropriate training and carefully select the bone bed in order to minimize the risk of early implant failure.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.2
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• pp.161-168
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• 2020

Failure of fixed implant supported prosthesis is caused by biomechanical factors such as excessive occlusal stress and biological factors such as bacterial infections and inflammation. Implants with severe bone resorption that have worsened without being resolved due to implant complications should be removed and then new treatments should be planned, taking into account remaining teeth, remaining implants, and residual alveolar. The patient of this case removed some of fixed implant prosthesis of mandible. The condition of the remaining alveolar bone was reassessed for further implant replacement and a few implants were placed. Then implant assisted removable partial denture (IAPRD) treatment is performed using implant surveyed bridge as abutment. Through this treatment, the clinical results were satisfactory on aspect of masticatory function recovery and oral hygiene management.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.1
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• pp.1-13
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• 2012

Short implants are used in parts which have anatomical structures like maxillary sinus, inferior alveolar nerve and limited alveolar height due to severe alveolar bone resorption. In these case, there are no need of additional bone augmentation so there are advantages like reduced entire treatment time, reduced patient's discomfort and protection of important anatomical structures. The aim of this study is, in implants whose length is less than 10mm, to analyze the impact of implant length, diameter, location of implant placement, presence of bone graft, presence of prosthesis splinting on survival rates and marginal bone resorption. The samples used in this study were 227 implants, less than 10mm, placed in 137 patients in Wonkwang university dental hospital implant center. From dental charts the information about implant length, diameter, location of implant placement, presence of bone graft, presence of prosthesis splinting were obtained. Emago advanced v5.6(Oral diagnostic systems, Amsterdam, The Netherlands)program was used to measure the amount of marginal bone resorption. Out of total 227 implants, resulting in 96.5 % of survival rate. There was a tendency toward higher failure rates for the maxilla and bone graft site. No significant difference in marginal bone resorption was found associated with length of implants(p>0.05) and neither with the diameter of implants. Among the risk factors examined, more failure rates of short implants can be attributed to poor bone quality in the maxilla and presence of bone graft. At implants under 10mm, length, diameter, location of implant placement, bone graft and splinting of prosthesis didn't affect marginal bone loss.

• Journal of Yeungnam Medical Science
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• v.31 no.2
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• pp.144-147
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• 2014

Despite the necessity of surgical aortic valve replacement, many patients with symptomatic severe aortic stenosis (AS) cannot undergo surgery because of their severe comorbidities. In these high-risk patients, percutaneous transcatheter aortic valve implantation (TAVI) can be safely accomplished. However, no study has shown that TAVI can be performed for patients with severe AS accompanied by acute decompensated heart failure. In this case report, 1 patient presented a case of severe pulmonary hypertension with decompensated heart failure after diagnosis with severe AS, and was successfully treated via emergency TAVI. Without any invasive treatment, acute decompensated heart failure with severe pulmonary hypertension is common in patients with severe AS, and it can increase mortality rates. In conclusion, TAVI can be considered one of the treatment options for severe as presented as acute decompensated heart failure patients with pulmonary hypertension.

• Journal of Dental Rehabilitation and Applied Science
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• v.36 no.3
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• pp.176-182
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• 2020

Purpose: To evaluate the effects of load direction, number of implants, and alignment of implant position on stress distribution in implant, prosthesis, and bone tissue. Materials and Methods: Four 3D models were made to simulate posterior mandible bone block: two implants and 3-unit fixed dental prosthesis (FDP) with a pontic in the center (model M1), two implants and 3-unit FDP with a cantilever pontic at one end (model M2), FDP supported by three implants with straight line placement (model M3) and FDP supported by three implants with staggered implant configuration (model M4). The applied force was 120 N axially or 120 N obliquely. Results: Peak von Mises stresses caused by oblique occlusal force were 3.4 to 5.1 times higher in the implant and 3.5 to 8.3 times higher in the alveolar bone than those stresses caused by axial occlusal force. In model M2, the connector area of the distal cantilever in the prosthesis generated the highest von Mises stresses among all models. With the design of a large number of implants, low stresses were generated. When three implants were placed, there were no significant differences in the magnitude of stress between staggered arrangement and straight arrangement. Conclusion: The effect of staggering alignment on implant stress was negligible. However, the number of implants had a significant effect on stress magnitude.

• Journal of Chest Surgery
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• v.34 no.9
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• pp.686-691
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• 2001

Background: The Duromedics valve has been used in Korea since 1982, however, but there were no long term clinical results that have been reported. This paper presents the long term clinical results of Duromedics valve implanted in Seoul National University Hospital. Material and method: Between 1987, 23 patients underwnet cardiac valve replacement with Duromedics mechanical valve. There were 8 mitral valve replacements, 5 aortic valve replacements, one tricuspid valve replacement, 6 aortic and mitral valve replacements, and one mitral and tricuspid valve replacement. There were 12 men and 11 women. The mean age was 35$\pm$10(15~52) years. We evaluated the clinical performance of Duromedics cardiac prosthesis. Result: The early operative mortality was 4.3%(1/23) and the late morlatity was 4.3%(1/23). Causes of death were low cardiac output syndrome and structural valvular failure. The mean follow-up duration was 133$\pm$43(8~157) months. There were 3 reoperations. The causes of reoperations were thrombosis and structural failure and nonstructural valvular failure. The actuarial survival rate at 10 years was 90.9%. Conclusion: Although the number of patients was not sufficient for effective clinical study, the long term clinical results of Duromedics valve was relatively good and there was no structural defect in this mechanical valve. However, more research is needed in the future.

• Journal of Chest Surgery
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• v.29 no.6
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• pp.651-654
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• 1996

Recently, we report a surgical experience of one case of acute prosthetic valve failure due to throe- bosis. The patient was 39-year old male who complained of dyspnea and orthopnea for 3 days before admission. The patient had not taken anticoagulant therapy for recent 4 months against medical ad- vice. The limitation of valve motion was revealed on echocardiography. We performed emergency reoperation with thrombectomy and prosthetic valve replacement. The patient had anuncomplicated postoperative course and have been followed up.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.10 no.1
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• pp.56-70
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• 2001

The use of resin-bonded fixed partial dentures described in the early 1980s caused an conservative way to preserve tooth structure in the restorative dental community. The treatment of patients with requires long term analysis of clinical application and basic research. Failure rates of these prosthesis ranged from 3% to 55%. These varieties were orginated by different techniques, materials, tooth preparation methods and diverse clinical situations. This article review was focused on the standard long term results and in vitro studies on bond strength between metal and teeth. From this, many useful clinical guidelines to RBFPD could be adopted to clinical dentistry. For successful results, careful case selection and good clinical skills are needed. And appropriate techniques for each situations should be adopted. Also, RBFPD using new materials like all-ceramics, FRC/Ceromer was introduced.

• Journal of Dental Rehabilitation and Applied Science
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• v.19 no.2
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• pp.105-108
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• 2003

After stage-two surgery, the highest incidence of failure has been attributed to implant overload. However, the biomechanical factors cited inthe literature that contribute to implant overload, such as bone type, cuspal inclination, horizontal offset, maxillary compared to mandibular arch, the inclusion of natural teeth within the prosthesis, and occlusal harmony are superimposed on physiologic variations. Following two cases, including reduction of cuspal inclination and usage of modified incisal pin, showed a method of contouring occlusal surface for reduction of unpreditable implant overload.