(The) changes of the properties of dental excavating burs according to various sterilization methods

치의학과/박사[한글] 치아 절삭용 bur의 물성과 몇 가지 소독처리 후의 변화를 알아보기 위하여 세 종류의 치아 절삭용 bur를 선택하여 성분분석과 경도를 실험한 후, 소독처리 하지 않은 대조군롸 고압증기멸균법, sodium nitrite를 포함하는 고압증기멸균법, 화학중기멸균법 및 glutar aldehyde를 이용한 냉각멸균법의 네 가지 소독방법을 각각 10회, 20회, 30회, 40회 및 50회 시행한 실험군을 입체현미경을 이용하여 부식 양상을 관찰하고, 절삭효율, 경부의 강도를 실험하여 다음과 같은 결과를 얻었다. 1. Bur의 head 부위는 tungsten과 cobalt가 주성분이었고, shank 부위는 i개n이 주성분이었으며, shank 부위에서 Komet는 chromium을 약 13% 함유하고 있었다. 2. 경도는 bur head 부위가 세 제품 모두 shank에 비해 높았고(p<0.01), head 부위의 경도는 Komet가 가장 낮았고(p<0.05), shank 부위는 S.S.White가 월등히 높았다(P<0.01). 3. 소독처리 후 입체현미경 관찰결과 소독방법간의 비교에서 화학증기멸균한 군의부식이 가장 적었으며, 부식저항성은 Komet, S.S.White, Jet 순으로 감소하였다. 4. 고압증기멸균시의 Jet 와 Komet Glutarex를 이용한 냉각멸균시의 모든 bur의 절삭효율은 소독회수에 관계없이 대조군에 비해서 감소하였다(p<0.05). 5. Sodium nitrite를 포함한 고압중기멸균법에서의 S.S.White만 결부강도의 감소가 있었고(p<0.05), 이를 제외한 모든 bur의 경부강도는 소독방법과 소독회수에 영향을 받지 않았다. 이상의 연구결과로 고압중기멸균법, Sodium nitrite를 포함한 고압증기멸균법, 화학중기멸균법 및 glutaraldehyde를 이용한 냉각멸균법의 네 가지 방법 중에서 부식저항성, 절삭효율 및 경부강도를 고려할 때 화학증기멸균법이 임상적으로 바람직하다고 사료되었다. The changes of the properties of dental excavating burs according to various sterilization methods Kwang-Mahn Kim, 0.D.S., M.S.D. Department of Dental Science, The Graduate School, Yonsei University (Directed by Associated Professor Kroung-Nam Kim, D.D.S., M.S.D., Ph.D.) The purpose of this study was to assess the physical and mechanical properties of dental excavating burs. Three different kinds of #558 friction grip type dental excavating burs(S.S.White, Jet and Knmet burs manufactured by S.S.White, Sybron and Brasseler) were selected. Specimens were classified by non-sterilized control group and 4 testing groups with autoclaving, autoclaving using sodium nitrite, chemiclaving, and cold sterilization using Glutarex performed 10, 20, 30, 40 and 50 times. Components were analyzed by EPMA, surface hardness measured by Vickers hardness tester, degrees of corrosion, cutting efficiency, and neck strength tested before arts after sterilization. The results of tests were compared with normal control group. The results were as follows ; 1. Main components of heads of the burs were tungsten and cobalt. Iron was the main component of shanks of the burs, The shank of Komet contained 13% of chromium. 2. Surface hardness of heads were higher than shanks(P<0.01). Komet showed the lowest head hardness(p<0.05). S.S.White showed the highest shank hardness(p<0.01). 3. Chemiclaving showed the lowest corrosion. Komet showed the highest corrosion resistance and Jet the lowest. 4. Jet and Komet showed decrease in cutting efficiency after autoclaving irrespective of autoclaving times(p<0.05). All kinds of burs showed decrease in cutting efficiency after cold sterilization using Glutarex irrespective of cold sterilization times(p<0.05). 5. Neck strength of S.S.White sterilized auloclaving using sodium nitrite were decreased(p<0.05), but neck strength of other testing groups showed no changes irrespective of sterilization methods and times. In summary, chemiclaving appears to be the comparatively desirable clinical sterilization method considering resistance of corrosion, cutting efficiency and neck strength. [영문] The purpose of this study was to assess the physical and mechanical properties of dental excavating burs. Three different kinds of #558 friction grip type dental excavating burs(S.S.White, Jet and Knmet burs manufactured by S.S.White, Sybron and Brasseler) were selected. Specimens were classified by non-sterilized control group and 4 testing groups with autoclaving, autoclaving using sodium nitrite, chemiclaving, and cold sterilization using Glutarex performed 10, 20, 30, 40 and 50 times. Components were analyzed by EPMA, surface hardness measured by Vickers hardness tester, degrees of corrosion, cutting efficiency, and neck strength tested before arts after sterilization. The results of tests were compared with normal control group. The results were as follows ; 1. Main components of heads of the burs were tungsten and cobalt. Iron was the main component of shanks of the burs, The shank of Komet contained 13% of chromium. 2. Surface hardness of heads were higher than shanks(P<0.01). Komet showed the lowest head hardness(p<0.05). S.S.White showed the highest shank hardness(p<0.01). 3. Chemiclaving showed the lowest corrosion. Komet showed the highest corrosion resistance and Jet the lowest. 4. Jet and Komet showed decrease in cutting efficiency after autoclaving irrespective of autoclaving times(p<0.05). All kinds of burs showed decrease in cutting efficiency after cold sterilization using Glutarex irrespective of cold sterilization times(p<0.05). 5. Neck strength of S.S.White sterilized auloclaving using sodium nitrite were decreased(p