The purpose of this study was to investigate the effect of cytokine-induced osteoclastogenesis on tooth movement related to orthodontic force. We evaluated the cytotoxicity as well as the expression of OPG and RANKL, which influence the homeostasis of bone metabolism. Titanium particles were applied to human periodontal ligament cells and subcultured fourth generation cells. The ALP assay and the MTT assay were used to assess changes in cytotoxicity. After 48 hours, cytotoxicity increased proportionally with the concentration of titanium. With 20 mg, the cytotoxicity was the lowest. R T-PCR was u sed for assessing m R NA l evels of O PG a nd R ANKL; after 96 hours, t he m R NAs of O PG a nd R ANKL increased steeply. A western blot analysis showed that with 20 mg of titanium, the protein expression of OPG increased linearly with time, especially a fter 96 hours, while t he p rotein e xpression o f RANKL d id n ot s how significant changes with titanium processing. Given the increase in OPG expression after the initial cytotoxicity, changes in cytotoxicity with titanium may be attributable to the antagonistic effect of OPG on cytotoxicity

I. 서론
 II. 재료 및 방법
  1. 연구방법
  2. 통계처리
 III. 결과
  1. 치주인대세포주의 생존력 분석
  2. Reverse Transcriptase-Polymerase ChainReaction(RT-PCR)분석법에 의한 RANKL, OPG발현
  3. Western blot analysis를 이용한 OPG, RANKLProtein의 발현
 IV. 고찰
 V. 결론
 VI. 참고문헌

• 조형준(닥터스마일치과) | Hyung Jun Cho
• 나유진(경희대학교 자연과학대학 생물학과) | Yu Jin Na
• 정용석(경희대학교 자연과학대학 생물학과) | Yong Suk Jeong
• 홍지숙(한림대학교의료원 강동성심병원 치과교정과) | Ji Suk Hong
• 김윤지(한림대학교의료원 강동성심병원 치과교정과) | Yoon Ji Kim
• 이종헌(단국대학교 치과대학 구강병리학교실) | Chong Heon Lee
• 천재식(구강생리학교실) | Gae Sik Cheon
• 박양호(한림대학교의료원 강동성심병원 치과교정과) | Yang Ho Park correspondence