• 한국화재소방학회논문지
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• 제34권3호
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• pp.67-75
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• 2020

본 연구는 산업현장에서 사용되는 분전반 내 터미널 블록의 탄화 사고를 예방하기 위한 목적으로, 전선 접속부 볼트의 이상(Abnormal) 풀림 각도에 따라 변화하는 정상전류 및 과전류의 접속부 발열 위험성을 확인하고 열적 특성을 통해 위험성을 분석하였다. 이를 위하여 터미널 블록에 Resistance temperature detector (RTD) 센서 보드를 설치하여 실시간으로 터미널 블록의 발열 온도와 온도의 변화를 측정하는 새로운 기법을 적용하였다. 실험 결과 정격 전류가 작은 터미널 블록 모델의 발열 온도가 높게 나타남에 따라 부하전류에 따른 터미널 블록 용량 선정의 중요성을 확인하였다. 또한 정격전류가 높은 터미널 블록의 정격 전류가 높을수록, 이상 풀림 정도가 클수록 탄화점이 빨라짐을 확인하였다. 이러한 발열 온도 모니터링을 통해서 실시간 발열 온도를 측정할 수 있었고 열적 분석을 통해서 단계별 위험수위 설정이 가능함을 확인할 수 있었다. 본 연구의 탄화 위험성 측정 및 분석 결과는 탄화로 인한 화재 위험성에 대한 응용 연구의 이론적 기초를 제공할 수 있다. 또한 본 연구에서 새롭게 적용한 온도 센서 보드를 활용한 열화 측정 방법은 위험수준관리 및 전기적 접촉 불량으로 인한 화재 예방 활동에 광범위하게 적용 가능할 것으로 사료된다.

• Journal of Korean Neurosurgical Society
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• 제30권10호
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• pp.1170-1176
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• 2001

Objective : The purpose of the study was to evaluate the clinical and radiological results after discectomy and Lubboc bone graft in the surgical management of the cervical diseases with a new titanium interbody implant and integrated screw fixation(PCB) by anterior approach. Methods : The authors retrospectively analyzed 28 cases of anterior cervical fusion with PCB system and Lubboc bone(xeno graft) from september 1998 to december 2000. Twenty-eight patients with cervical diseases underwent decompression cervical lesion and followed from 5 to 27 months with a mean follow-up of 14 months. There patients were evaluated with clinically and radiologically at immediate postoperative period and at 3, 6, 9, and 12 months. Result : The authors investigated the pre- and postoperative intervertebral disc space, clinical outcomes, radiography fusion rate, and Cobb angle in the fixed segments by anterior approach. The lordotic angles and height of disc space were increased after the operation. The clinical outcome of patients follow-up was good or excellent result based on Odom's criteria with improvement of clinical symptom in about 92.9% of the cervical diseases. Two patients showed loosening of the lower and upper cervical screw of PCB instruments, and two patients showed swallowing difficulty and wound infection Conclusion : The PCB system is a new implant for anterior cervical interbody fusion in the degenerative cervical disease and disc herniations. It provides immediate stability and segment distraction. The results of this study indicate that the PCB system is safe, easy handling of hardware, less complications, high fusion rate, and has provide the keeping the intervertebral disc space height and lordotic angles.

• Clinics in Shoulder and Elbow
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• 제17권1호
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• pp.10-17
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• 2014

Background: The aim of this study was to assess the clinical outcomes after treatment of proximal humeral fractures with locking plates, and to determine which factors influence the clinical and radiological outcomes. Methods: Fifty six patients who were treated with locking plates for proximal humeral fractures and had been followed for more than 1 year were enrolled in this study. We performed functional evaluation using the Constant score and analyzed radiographic results. The following factors that may potentially influence the clinical outcomes were assessed: age, gender, type of fracture, presence of medial metaphyseal comminution, bone mineral density, anatomical reduction, restoration of medial mechanical support, and postoperative complications. Results: The mean Constant score was 70.1 points at the final follow-up. Female gender, 4-part fractures, AO type-C fractures, and fractures with medial metaphyseal comminution were associated with a poor clinical outcome. On the other hand, restoration of medial mechanical support and accurate anatomical reduction had a positive influence on clinical outcomes. Postoperative complications resulted in 3 patients (intra-articular screw perforation: 1 patient, varus deformity with screw loosening: 1 patient, nonunion: 1 patient). Conclusions: When treating proximal humeral fractures with locking plate fixation, following factors: a female gender, Neer type 4-part fracture, AO type C fracture, and medial metaphyseal comminution are important risk factors that surgeons should take into consideration. Factors that contribute to better clinical outcomes of operative treatment for humeral fractures are accurate anatomical reduction and restoration of medial mechanical support.

• The Journal of Advanced Prosthodontics
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• 제8권6호
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• pp.494-503
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• 2016

PURPOSE. The aim of this study was to compare the efficacies of two-implant splinting (2-IS) and single-implant restoration (1-IR) in the first and second molar regions over a mean functional loading period (FLP) of 40 months, and to propose the appropriate clinical considerations for the splinting technique. MATERIALS AND METHODS. The following clinical factors were examined in the 1-IR and 2-IS groups based on the total hospital records of the patients: sex, mean age, implant location, FLP, bone grafting, clinical crown-implant ratio, crown height space, and horizontal distance. The mechanical complications [i.e., screw loosening (SL), screw fracture, crown fracture, and repeated SL] and biological complications [i.e., peri-implant mucositis (PM) and peri-implantitis (PI)] were also evaluated for each patient. In analysis of two groups, the chi-square test and Student's t-test were used to identify the relationship between clinical factors and complication rates. The optimal cutoff value for the FLP based on complications was evaluated using receiver operating characteristics analysis. RESULTS. In total, 234 patients with 408 implants that had been placed during 2005 - 2014 were investigated. The incident rates of SL (P<.001), PM (P=.002), and PI (P=.046) differed significantly between the 1-IR and 2-IS groups. The FLP was the only meaningful clinical factor for mechanical and biological complication rates in 2-IS. CONCLUSION. The mechanical complication rates were lower for 2-IS than for 1-IR, while the biological complication rates were higher for 2-IS. FLP of 39.80 and 46.57 months were the reference follow-up periods for preventing biological and mechanical complications, respectively.

• The Journal of Advanced Prosthodontics
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• 제8권6호
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• pp.465-471
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• 2016

PURPOSE. The purpose of this study is to evaluate the stability of interface between Co-Cr-Mo (CCM) UCLA abutment and external hex implant. MATERIALS AND METHODS. Sixteen external hex implant fixtures were assigned to two groups (CCM and Gold group) and were embedded in molds using clear acrylic resin. Screw-retained prostheses were constructed using CCM UCLA abutment and Gold UCLA abutment. The external implant fixture and screw-retained prostheses were connected using abutment screws. After the abutments were tightened to 30 Ncm torque, 5 kg thermocyclic functional loading was applied by chewing simulator. A target of $1.0{\times}10^6$cycles was applied. After cyclic loading, removal torque values were recorded using a driving torque tester, and the interface between implant fixture and abutment was evaluated by scanning electronic microscope (SEM). The means and standard deviations (SD) between the CCM and Gold groups were analyzed with independent t-test at the significance level of 0.05. RESULTS. Fractures of crowns, abutments, abutment screws, and fixtures and loosening of abutment screws were not observed after thermocyclic loading. There were no statistically significant differences at the recorded removal torque values between CCM and Gold groups (P>.05). SEM analysis revealed that remarkable wear patterns were observed at the abutment interface only for Gold UCLA abutments. Those patterns were not observed for other specimens. CONCLUSION. Within the limit of this study, CCM UCLA abutment has no statistically significant difference in the stability of interface with external hex implant, compared with Gold UCLA abutment.

• 대한족부족관절학회지
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• 제16권3호
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• pp.175-180
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• 2012

Purpose: To evaluate the radiological and clinical results after open reduction and internal fixation with calcaneal F plate and locking calcaneal plate using lateral extensile approach in the treatment of intra-articular calcaneal fracture Materials and Methods: This study included 34 cases of 33 patients followed up for at least 6 months postoperatively. F plate was applied in 18 cases (Group 1), locking plate was used in 16 cases (Group 2) and compared radiological and clinical results between two groups. Results: Radiollogically, the mean Bohler angle was improved from $5.5^{\circ}$ preoperatively to $20.1^{\circ}$ postoperatively and $18.8^{\circ}$ at the last follow up in group 1 and $8.6^{\circ}$ preoperatively, $21.4^{\circ}$ postoperatively and $20.3^{\circ}$ at last follow up in group 2. Bone union was observed in all cases and 4 cases of screw loosening were noted in Group 1 with extended fracture to anterior process. At the last follow up, both groups showed clinical results in American orthopedic foot and ankle society ankle hindfoot score, 76(77 in Sanders type II and 75 in type III) in group 1 and 72(73 in type II and 70 in type III) in group 2. Conclusion: F plate and locking plate showed firm fixation and satisfactory clinical results in the treatment of intra-articular calcaneal fracture. We suggest applying locking plate in cases with extended fracture to anterior process, considering screw loosenings in those who were treated with F plate fixation.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 가을학술발표대회논문집
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• pp.155-156
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• 2023

In the case of steel door frames commonly found in general buildings, there are various assembly methods such as rivets, bolts, and welding, but the welding method is generally used. However, this welding joint method has many problems, such as distortion due to heat and damage due to external shock. In particular, when used as a fire door, problems may occur in the event of a fire due to distortion caused by heat from welding and the weak welded joint area. In the case of rivet or welded joints, when moved after assembly, joint loosening due to external shock may occur. Problems may arise where the bonding strength becomes weak. In addition, with the recent increase in high-rise buildings and larger buildings, when assembly is completed and brought to the site, a place is needed to store it, and in addition, there is a problem in that it has to be transported several times in small quantities to the installation site, which is another problem of time and cost loss. This is coming to the fore. In order to fundamentally solve this problem, we have researched and developed a non-welding door frame that can be assembled on site. We have researched and developed three assembly methods: screw-type, insert-type, and protrusion-type. Non-welded door frames are small in size and easy to package, making them advantageous for domestic and overseas exports.

• 대한심미치과학회지
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• 제23권1호
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• pp.34-40
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• 2014

부분 무치악을 수복하는 데 있어서 선택할 수 있는 치료의 옵션으로는 전통적인 국소의치와 임플란트 지지-고정성 보철물 등이 있다. 하지만, 환자의 전신적 또는 구강의 상태(수술적인 술식이 제한되는 전신병력, 지지조직의 부족 그리고 골유착에 실패한 임플란트)와 치료비용에 대한 허용 정도에 따라 모든 옵션이 항상 가능한 것은 아니다. 가철성 국소의치는 임플란트 고정성 보철물에 비해 구강위생 관리 및 상,하악 악간관계의 부조화를 수정하기에 편리한 장점이 있다. 최근에는 전략적 위치에 임플란트를 식립하여 기존 악궁 형태에서는 제한되는 국소의치 디자인의 한계를 개선할 수 있는 임플란트지지형 RPD(Implant Supported Removable Partial Denture)가 새로운 방안으로 대두되고 있다. ISRPD는 전략적 위치에 임플란트를 식립하여 역학적인 한계를 극복할 수 있을 뿐 만 아니라 전악의 임플란트지지형 고정성 보철이 제한되는 환자에서 보다 경제적이고 현실적인 보철적 해결책이 될 수 있다. 따라서, RPD를 이용한 보철계획 수립시 전략적 위치에서의 임플란트의 사용은 고전적인 가철성 국소 의치에서보다 유지력과 안정성을 증진시키고 구강위생관리 또한 용이하여 환자의 적응도를 높이는 방안으로 고려될 수 있다. 본 증례는 상악 양측 구치부의 임플란트 고정성 보철,하악의 bar-type overdenture를 사용중이던 59세 남성환자에서 상악 #15i임플란트의 abutment screw fracture와 임플란트의 골유착 실패로 인한 다수 임플란트를 발거 후 남은 #15i,24i,25,26,i의 잔존 임플란트와 #23 자연치를 활용해 상악에 ISRPD를 적용한 경우이다. #23 surveyed crown, #24i=25i=26i surveyed bridge 및 #15i에 gold coping을 제작하여 국소의치의 지지와 유지,안정을 도모하였다.최종 보철물을 장착하고 2년간 주기적인 follow up 통해 예후를 관찰중이며 지대치로 사용한 임플란트에서 screw loosening이나 파절, 골흡수 등의 증상은 현재까지 관찰되지 않았다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제38권6호
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• pp.371-378
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• 2012

Many longitudinal studies have reported the successful osseointegration of dental implants, with survival rates approaching 90-95%. However, implants regarded as a "success" may have also failed to undergo osseointegration. A variety of complications and failures have been observed, including implant fracture - a rare and delayed biomechanical complication with serious clinical outcomes. Given the increasing popularity of dental implants, an increase in the number of failures due to late fractures is expected. This study sought to determine the rate of implant fractures and factors associated with its development. This retrospective evaluation analyzed implants placed at Wonkwang Dental Hospital (from 1996 to the present). In our study we found that the frequency of dental implant fractures was very low (0.23%, 8 implant fractures out of 3,500 implants placed). All observed fractures were associated with hybrid-surface threaded implants (with diameter of 4.0 or 3.75 mm). Prosthetic or abutment screw loosening preceded implant fracture in a majority of these cases.

• 대한치과보철학회지
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• 제39권1호
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• pp.25-36
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• 2001

Among the numerous factors contributing to implant failure, the most common are infection, failure of proper healing and overload. These factors may occur combined. Implant fractures are one of the complications resulting from overload. Implant fracture is not a common feature, but once it occurs it causes very unpleasant circumstances for the patient as well as for the practitioner. Only few studies have been reported regarding this subject. Thus, little is known about its solutions. It is important that analyzing reasons for implant fracture and finding appropriate solutions. Factors leading to implant fracture are design, material defects, nonpassive fit of prosthetic framework and biomechanical overload. Previous studies have reported that implant fractures ares associated with marginal bone loss and occur mostly in the posterior regions and that most patients showing parafunctional habits also have implant fracture. Abutment and gold screw loosening or fracture were also observed in some of the cases previous to implant fracture. Similar observations were seen in our hospital as well. The following cases will present implant fracture cases which have been successfully treated regarding function and biomechanics. This was achieved by means of using increased number of futures, increasing fixture diameter and establishing proper occlusion.