• Weed & Turfgrass Science
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• 제4권4호
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• pp.376-382
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• 2015

동전마름병은 Sclerotinia homoeocarpa가 원인균으로 주로 한지형 잔디에 발생하는 주요 병이다. 본 연구는 이쑤시개를 이용하여 동전마름병 전염원 검출과 처리물량을 달리하여 약제 살포하였을 때 병원균 검출 특성을 조사하기 위하여 수행하였다. 동전마름병 병원균을 검출한 결과 병반 중심의 잎 부위에서는 100% 검출되었으며, 대취 부분에서는 83.3%가 검출되었으나 토양에서는 전혀 검출되지 않았다(대취층 아래 1, 2와 3 cm). 병반 중심부와 가장자리에서는 100% 검출되었으며 병반으로부터 1.5 cm 떨어진 부분에서는 13% 검출되었으며 병반으로부터 3와 4.5 cm 떨어진 부분에서 병원균의 분리빈도는 각각 3와 0%로 나타났다. 동전마름병 병원균은 병반으로부터 1.5 cm 떨어진 지점의 잎과 대취에서는 73.3%와 20%가 검출되었으며 3 cm 떨어진 부분과 4.5 cm 떨어진 부분에서 각각 46.6%와 13.3% 병원균이 검출되었다. 토양부분에서는 병원균이 검출되지 않았으며 전염원 검출 빈도는 병반으로부터 멀어질수록 낮아지는 경향이었다. 두 가지 약제를 같은 약량으로 2.26와 6.78 L의 물에 희석하여 처리한 결과 병원균 검출빈도는 Chlorothalonil (CH) 처리구보다 Propiconazole (PP) 처리구에서 높게 나타났다. 병반중심부에서 CH의 경우 검출 빈도는 15.5%로 PP의 경우 20.5%로 나타났다. 잎에서는 CH약제 처리구는 각각 15.5%와 2.2%가 검출되었으며 PP 처리구에서 이보다 높은 20.5%와 4.4%가 검출되었다. 대취층에서 전염원은 CH 처리구에서 물 2.26 L와 12.7%로 물 6.78 L가 2.2%로 검출되었다. 가장자리에서는 잎 부분을 검출한 결과 CH의 경우 물 2.26 L 처리구에서는 2.7%로 물 6.78L에서는 검출되지 않았으며 PP의 경우 물 2.26 L에서 9.4%로 물 6.78L에서는 CH 처리구와 같이 검출되지 않은 것으로 나타났다. 이쑤시개 방법은 빠르고 쉽게 동전마름병을 검출하여 전염원의 분포 조사 및 전염원 형성 예측을 할 수 있는 방법으로 제안한다.

• 대한치과보철학회지
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• 제43권4호
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• pp.528-543
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• 2005

Statement of problem: Repeated delivery and removal of abutment cause some changes such as wear, scratch or defect of hexagonal structure. It may increase the value of rotational freedom(RF) between hexagonal structures. Purpose: The purpose of this study was to evaluate surface changes and rotational freedom between the external hexagon of the implant fixture and internal hexagon of abutment after repeated delivery and removal under SEM and toolmaker's microscope. Materials and methods: Implant systems used for this study were 3i and Avana. Seven pail's of implant fixture, abutment and abutment screws for each system were selected and all fixtures were perpendicularly mounted in liquid unsaturated polyesther with dental surveyor. Each one was embedded beneath the platform of fixture. Surfaces of hexagonal structure before repeated closing and opening of abutment were observed using SEM and rotational freedom was measured by using toolmaker's microscope. Each abutment was secured to the implant future by each abutment screw with recommended torque value using a digital torque controller and was repeatedly delivered and removed by 20 times respectively. After experiment, evaluation for the change of hexagonal structures and measurement of rotational freedom were performed. Result : The results were as follows; 1. Wear of contact area between implant fixture and abutment was considerable in both 3i and Avana system. Scratches and defects were frequently observed at the line-angle of hexagonal structures of implant fixture and abutment. 2. In the SEM view of the external hexagon of implant fixture, the point-angle areas at the corner edge of hexagon were severely worn out in both systems. It was more notable in the case of 3i systems than in that of Avana systems. 3. In the SEM view of the internal hexagon of abutment, Gingi-Hue abutment of 3i systems showed severe wear in micro-stop contacts that were machined into the corners to prevent rotation and cemented abutment of Avana systems showed wear in both surface area adjacent to the corner mating with external hexagon of implant fixture. 4 The mean values of rotational freedom between the external hexagon of the implant fixture and internal hexagon of abutment were 0.48$\pm$0.04$^{\circ}$ in pre-tested 3i systems and 1.18$\pm$0.25$^{\circ}$ after test, and 1.80$\pm$0.04$^{\circ}$ in pre-tested Avana systems and 2.61$\pm$0.16$^{\circ}$ after test. 5. Changes of rotational freedom after test shouted statistical)y a significant increase in both 3i and Avana systems(P<0.05, paired t-test). 6. Statistically, there was no significant difference between amount of increase in the rotational freedom of 3i systems and amount of increase in that of Avana ones(P>0.05, unpaired t-test). Conclusion: Conclusively, it was considered that repeated delivery and remove of abutment by 20 times would not have influence on screw joint stability. However, it caused statistically the significant change of rotational freedom in tested systems. Therefore, it is suggested that repeated delivery and remove of abutment should be minimal as possible as it could be and be done carefully Additionally, it is suggested that the means or treatment to prevent the wear of mating components should be devised.