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백서에서 치아이동 후 보정기간 동안 교합이 치주조직섬유의 재형성에 미치는 영향
정권희,박영준,이기헌,황현식 대한치과교정학회 2003 대한치과교정학회지 Vol.33 No.2
본 연구는 실험적 치아이동 후 보정기간 동안 교합이 치주조직섬유의 물리적 강도에 미치는 영향을 알아보고자 시행되었다. 체중 200g 내외의 Sprague-Dawley계 백서 수컷에서 상악 양측 제1대구치와 2대구치 사이에 교정용 고무줄을 삽입하여 4일 동안 치아를 이동시킨 다음, 각 실험동물의 하악 좌측 베1, 2, 3대구치를 발치하여 우측은 대합치가 있는 교합측으로, 좌측은 비교합측으로 구분하였다. 상악 제1대구치와 2대구치 사이의 인접면에 유지구를 형성하고 광중합형 레진으로 채워 보정을 시행한 후 시작 0일, 4일, 8일, 12일, 16일 또는 20일 경과한 후 백서를 희생시킨 다음, 만능물성 시험기를 이용하여 상악 제1대구치를 발치할 때 필요한 최대인장강도를 측정 좌우간 비교 분석하여 다음과 같은 결과를 얻었다. 1. 교합측은 비보정군에서 보정 4일, 8일, 12일, 16일, 20일군으로 갈수록 최대인장강도사 증가하였고, 보정 12일군 이후부터 통계적으로 유의한 차이를 보였다(p<0.05). 2. 비교합측은 비보정군에서 4일, 8일, 12일, 16일, 20일군으로 갈수록 최대인장강도가 증가하는 경향을 보였으나 통계적으로 유의한 차이를 보이지 않았다(p<0.05) 3. 교합측과 비교합측의 최대인장강도를 비교한 결과 보정 8일군까지 통계적으로 유의한 차이를 보이지 않았으나 (p>0.05), 보정 12일군 이후 보정 20일군까지 통계적으로 유의한 차이를 보였다(p<0.05). 이상의 결과는 실험적 치아이동 후 보정기간 동안 교합이 치주조직 섬유의 재형성에 영향을 미침으로 보정장치의 선택, 기간설정 등 보정계획서 교합에 대한 고려가 필요함을 시사하였다. The purpose of this study was to valuate the effect of occlusion on the mechanical strength of periodontal fibers during retention periods after experimental tooth movement. In the Sprague-Dawley male rats weighing 200g or more, the intraoral elastics were inserted into the both right and left interproximal space between upper first and second molars for tooth movement. After 4 days later, the left lower first, second, and third molars were extracted for differentiating the non-occlusal side from the occlusal side in the same mouth. At the same time the elastics were removes and than light cured resin was placed in the space between upper first and second molard following undercut was made for retention bilaterally. From the beginning of retention, 7 rats were sacrificed at 0, 4, 8, 12, 16, 20 days respectively. For evaluating of magnitude on the mechanical strength of periodontal tissue, the maximal shear load of the upper first molars were measured bilaterally during extraction using Instron Universal Testing Machine. The results of this study were obtained as follows : 1. In the occlusal side, the maximal shear load was increased from no retention to retention 20 days group as time was going and statistically difference was shown from retention 12 days group (p<0.05). 2. In the non-occlusal side, the maximal shear load was increased slightly from no retention 20 days group as time was going but there was no statistically difference (p>0.05) 3. The result compared with the maximal shear load between occlusal and nonocclusal side showed no statistically difference until retention 8 day group (p>0.05), but showed statistically difference from retention 12 day to 20 day group (p<0.05). These results show that occlusion had an effect on mechanical strength of the periodontal fibers during retention periods after experimental tooth movement; therefore, it is suggested that occlusion should be considered while the retainer types and retention period are planned.
백서에서 치아이동 후 보정기간 동안 교합이 치주조직 섬유의 재형성에 미치는 영향
정권희,이기헌,황현식,이석형 전남대학교 치의학연구소 2002 구강과학 Vol.14 No.2
The purpose of this study was to evaluate the effect of occlusion on the mechanical strength of periodontal fibers during retention periods after experimental tooth movement. In the Sprague-Dawley male rats weighing 200 g or more. The intraoral elastics was inserted into the interproximal space of upper the first and second molars. After 4th day of teeth movement, the left mandibular first, second, and third molars were extracted for differentiating the occlusal side from the non-occlusal side in the experimental groups. The intraoral elastics was removed and then light cured resin was placed in the interproximal space between the bilateral upper first and second molars following undercut was made for retention. From the day beginning retention, 7 rats were sacrified at 0, 4, 8, 12, 16, 20 days respectively. For evaluating of degree on the mechanical strength of periodontal tissue, maximal shear load of the bilateral upper first molars were measured by use of Instron Universal Testing Machine. The results of this study were obtained as follows: 1. In the occlusal side from no retention group to 4-day, 8-day, 12-day, 16-day, and retention 20-day group as time was going maximal shear load was increased and there was statistically difference from retention 12-day group(p<0.05). 2. In the non-occlusal side from no retention group to 4-day, 8-day, 12-day, 16-day, and retention 20-day group as time was going maximal shear load was increased slightly but there was no statistically difference(p>0.05). 3. The result compared with maximal shear load between occlusal and non-occlusal side showed no statistically difference until retention 8-daygroup(p>0.05), and showed statistically difference from retention 12-day to 20-day group(p<0.05). These results show that the occlusion had an effect on mechanical strength of the periodontal fibers during retention periods after experimental tooth movement; therefore, it is suggested that consideration of occlusion is required for the type and length of retention at the time of retention planning.
Silane 처리에 의한 MCM-41 과 KIT-1 메조포러스 물질의 수열 및 기계적 안정성 증진
정권희(Kweon Hee Jung),김종호(Jong Ho Kim),서곤(Gon Seo) 한국화학공학회 1997 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.35 No.6
The improvements in hydrothermal and mechanical stabilities of MCM-41 and KIT-1 mesoporous materials were examined from X-ray diffraction patterns and N₂ adsorption isotherms after hydrothermal and compression treatments. KIT-1 mesoporous material shows better hydrothermal stability than MCM-41 mesoporous material, while mechanical stability is better for MCM-41 mesoporous material. The hydrothermal and mechanical stabilities of mesoporous materials are remarkably improved by silane modification. Silane reacts with surface hydroxyl group, resulted in the improvement of the stabilities due to inhibition from water attack and crack initiation.
극저탄소강 정련에 미치는 감압하 산소 초음속 분사의 영향
반봉찬,김준식,정권희,안상복 대한금속재료학회(대한금속학회) 1999 대한금속·재료학회지 Vol.37 No.5
The effect of oxygen blowing under reduced pressure on decarburization and temperature changes were studied using an RH vacuum degasser. The decarburization rate was increased from 0.17 to 0.19min^(-1) by oxygen blowing during decarburization. It was caused by the increase of effective reaction area such as cavity and splash formed by oxygen blowing on melt surface. The carbon content below 20ppm was obtained by oxygen blowing. An average TDR (temperature drop-rate) during decarburization was decreased to -0.6℃/min by oxygen blowing. It was caused by post combustion of the carbon monoxide gas generated from melt decarburization in RH vacuum vessel.