• The Journal of Advanced Prosthodontics
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• 제2권2호
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• pp.54-57
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• 2010

PURPOSE. The aim of this study was to evaluate the periodontal and prosthodontic complications of multiple freestanding implants in the posterior jaws for up to 1 year of function. MATERIALS AND METHODS. Eight patients received 20 implants posterior to canines. Two or more implants were consecutively inserted to each patient. Single crowns were delivered onto the implants. Marginal bone loss, implant mobility, probing depth, and screw loosening were examined to evaluate the clinical success of such restorations for maximum 1 year of functional loading. RESULTS. All the implants performed well during the observation period. Neither periodontal nor prosthodontic complications were found except a slight porcelain chipping. While the marginal bone level was on average 0.09 mm lower around the implant after 6 months of loading, it was 0.15 mm higher after 1 year. CONCLUSION. Within the limits of this investigation, separate single-tooth implant restorations to replace consecutive missing teeth may clinically function well in the posterior jaw.

• 한국전기전자재료학회논문지
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• 제37권3호
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• pp.304-308
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• 2024

In this paper, in order to analyze the PMU data of the accident section, we collected the raw data of a total of 35 PMU installed at the Yeonggwang substation and tried to find a way to analyze the data, and analyzed the data using Excel format and formula. As a result, the three-phase voltage and current data of the PMU were calculated using formulas in Excel and interpreted as effective and reactive power, and it was possible to check the effective and reactive power of the accident section through the graph to see why it was different from before the accident. As a result, it was confirmed that each power was greatly reduced in the graph of the effective and reactive power of the accident section, and it was confirmed that the loss occurred as the power of the accident section was greatly reduced.

• 조명전기설비학회논문지
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• 제26권6호
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• pp.47-52
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• 2012

DAS(Distribution Automation System) is equipped with several software applications such as service restoration, loss minimization, and protective relay coordination. The software applications of DAS are very sensitive to the amount of section load being carried by a particular section of distribution lines. Moreover, each software application requires a different parameter of the section load according to its purpose. Therefore, This paper proposes a new section load management method using real-time measurement data of the distribution lines. In order to provide accurate data to DAS applications, this method considers section loads in terms of the relationship of power versus time. In order to establish that the proposed method is feasible, a performance-testing simulator was developed, and case studies were conducted for a modified real distribution network.

• 농약과학회지
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• 제14권2호
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• pp.133-137
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• 2010

콩탄저병의 수량에 미치는 영향을 조사하고, 요방제 수준을 설정하기 위하여 2년간 포장에서 시험하였다. 탄저병의 발병협율과 수량, 완전립수, 불완전립수, 협수와는 상관계수가 각각 -0.85, -0.78, 0.80, -0.64로 5% 수준에서 유의성이 있는 협수를 제외하고는 모두 1% 수준에서 고도의 상관이 있었다. 탄저병 발병협율(X)을 독립변수로 콩수량(Y)을 예측했을 때의 단순직선회기 모델은 Y=-1.7781X+164.22로 결정계수($R^2$)는 0.8092였다. 상기 회귀식에서 경제성을 고려하지 않고 수량에 영향을 주기 시작하는 요방제 수준은 발병협율 6.9%로 산출되었으며, 방제비용을 보상할 수 있는 경제적 피해수준 및 경제적 방제수준은 각각 발병협율 11.9%와 9.5% 로 산정되었다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제38권
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• pp.30.1-30.6
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• 2016

Background: The prognosis of wide implants tends to be controversial. While wider implants were initially expected to result in a larger osseointegration area and have higher levels of primary stability, they were reported to have a relatively high rate of failure. The clinical outcome of ultrawide implants of more than 6 mm in diameter was evaluated through a retrospective study. Methods: The investigation was conducted on patients who had received ultrawide implant (${\geq}6mm$ diameter) placements in Seoul National University Bundang Hospital from January 2008 to December 2013. Complications were investigated during the maintenance period, and marginal bone loss was measured using periapical radiography. Primary stability immediately after the implant placement and second stability after second surgery or during impression were measured using $Osstell^{(R)}$ Mentor (Osstell, Sweden) as an implant stability quotient (ISQ). Results: Fifty-eight implants were placed in 53 patients (30 male, 23 female), and they were observed for an average of $50.06{\pm}23.49$ months. The average ISQ value increased from $71.22{\pm}10.26$ to $77.48{\pm}8.98$ (P < 0.005). The primary and secondary stability shows significantly higher at the mandible than at the maxilla (P < 0.001). However, mean survival rate shows 98.28 %. Average marginal bone loss of 0.018 and 0.045 mm were measured at 12 and 24 months after the loading and 0.14 mm at final follow-up date (mean 46.25 months), respectively. Also in this study, the bone loss amount was noticeably small compared to regular implants reported in previous studies. Conclusions: The excellent clinical outcome of ultrawide implants was confirmed. It was determined that an ultrawide implant can be used as an alternative when the bone quality in the posterior teeth is relatively low or when a previous implant has failed.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제42권3호
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• pp.139-143
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• 2016

Objectives: If teeth are missing, super-eruption of teeth in the opposing arch can occur in the area and can change the occlusal plane. When missing teeth are replaced with implants, the oral surgeon must determine whether or not the super-erupted teeth need to be treated in order to normalize the occlusal plane. In this study, we evaluated the clinical prognosis of dentition after implant placement and prosthetic treatment were completed in an occlusal plane altered by super-erupted teeth in the opposing arch without additional treatment of the super-erupted teeth. Materials and Methods: Twenty-two patients (9 males, 13 females) were treated with implants and prosthetics without addressing the super-erupted opposing dentition from April 2004 to August 2012 at Seoul National University Bundang Hospital. A total of 33 implants were placed. Values of crestal bone loss, survival rates, and surgical and prosthetic complications for an average of 29.6 months after prosthetic loading were recorded. Results: In one case, the cover screw was exposed after implant surgery. The mean crestal bone loss was $0.09{\pm}0.30mm$. Of the 33 implants, 31 survived, a survival rate of 93.94%. A prosthetic complication occurred in one case but functioned well after correction. Conclusion: Favorable clinical results from prosthetic complications, crestal bone loss, and implant survival rates were exhibited in implants next to a super-erupted opposing tooth.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제49권6호
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• pp.324-331
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• 2023

Objectives: The purpose of this study was to evaluate the outcomes of implants placed in horizontally augmented alveolar ridges using porcine bone grafts and to investigate the long-term stability of the porcine bone grafts. Materials and Methods: A retrospective analysis was conducted on 49 sites that underwent horizontal ridge augmentation using porcine bone grafts and implant placement with a follow-up period longer than 5 years. Furthermore, additional analysis was conducted on 24 sites where porcine bone grafts were used exclusively for horizontal ridge augmentation and implant placement. Results: The mean follow-up period after prosthesis loading was 67.5 months, with a mean marginal bone loss of 0.23 mm at 1 year and a cumulative mean marginal bone loss of 0.40 mm over the entire follow-up period. Of the 49 implants, 2 were lost and 3 did not meet the success criteria, resulting in a survival rate of 95.9% and a success rate of 89.8%. In 24 sites, the mean marginal bone loss was 0.23 mm at 1 year and 0.41 mm at 65.8 months, with 100% survival and success rates. Conclusion: Porcine bone grafts can be successfully used in horizontal ridge augmentation for implant placement in cases of ridges with insufficient horizontal width.

• Journal of Periodontal and Implant Science
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• 제49권2호
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• pp.60-75
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• 2019

The primary aim of this systematic review was to assess the evidence on periodontal disease progression after treatment in patients receiving supportive periodontal therapy (SPT) and to identify predictors of clinical attachment level (CAL) loss. A protocol was developed to answer the following focused question: In adult patients treated for periodontitis, what is the disease progression in terms of CAL loss after surgical or non-surgical treatment? Randomized controlled clinical trials, prospective cohort studies, and longitudinal observational human studies with a minimum of 5 years of follow-up after surgical or non-surgical treatment that reported CAL and probing depth changes were selected. Seventeen publications reporting data from 14 investigations were included. Data from 964 patients with a follow-up range of 5-15 years was evaluated. When the CAL at the latest follow-up was compared to the CAL after active periodontal therapy, 10 of the included studies reported an overall mean CAL loss of ${\leq}0.5mm$, 3 studies reported a mean CAL loss of 0.5-1 mm, and 4 studies reported a mean CAL loss of >1 mm. Based on 7 publications, the percentage of sites showing a CAL loss of ${\geq}2mm$ varied from 3% to 20%, and a high percentage of sites with CAL loss was associated with poor oral hygiene, smoking, and poor compliance with SPT. The outcomes after periodontal therapy remained stable over time. Disease progression occurred in a reduced number of sites and patients, mostly associated with poor oral hygiene, poor compliance with SPT, and smoking.

• 전기전자학회논문지
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• 제26권1호
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• pp.89-94
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• 2022

W-대역(75-110GHz)은 기존 5G 대역에 비해 최소 10배 이상의 대역폭 활용이 가능한 대역이다. 따라서 가상 및 증강 현실과 같이 빠른 속도와 저지연이 요구되는 미래 이동통신에 적합한 대역 중 하나이다. 그러나 파장이 짧아 높은 경로손실을 가지며, 대기환경에도 매우 민감한 특성을 가진다. 따라서 향후 W-대역 통신 시스템 개발을 위해서는, 채널 환경에 따른 경로손실의 특성을 분석할 필요가 있다. 본 논문에서는 W-대역 경로손실의 특성을 분석하기 위해 랜덤 포레스트 기법을 이용, 다양한 채널 환경 파라미터에 따른 경로손실 데이터를 통해 거리 구간에 따른 채널 파라미터의 영향성을 분석하였다. 시뮬레이션 결과, 근거리에서의 경로손실은 거리가 가장 높은 영향성을 가지며, 채널 환경 요소는 거의 무시된다. 그러나 거리 구간이 길어질수록 거리의 영향성이 감소하는 동시에 클러터와 강우량의 영향성이 증가하였다.

• 한국전자통신학회논문지
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• 제7권4호
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• pp.867-871
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• 2012

본 논문에서는 폴리머 테이퍼링 도파로 영역을 포함하는 $1{\times}4$ 형태의 플라스틱 광섬유 커플러를 제안하고 구현하였다. 플라스틱 광섬유와 폴리머 사각 도파로의 접속면에서 광 누설 손실을 줄이기 위해 단면이 원형에서 구형으로 천천히 바뀐 플라스틱 광섬유를 도입하였다. 실리콘 고무로 만들어진 주형을 이용하여 소자를 제작하였다. 제작된 소자는 1.33 dB의 삽입손실과 2.2 dB의 평탄도를 보였다.