Insertion and removal torques according to orthodontic mini-screw design

교정용 미니스크류의 디자인에 따른 식립 및 제거 토오크

  • Cha, Jung-Yul (Department of Orthodontics, College of Dentistry, Yonsei University) ;
  • Yoon, Tae-Min (Department of Orthodontics, College of Dentistry, Yonsei University) ;
  • Hwang, Chung-Ju (Department of Orthodontics, College of Dentistry, Dental Science Research Institute, Yonsei University)
  • 차정열 (연세대학교 치과대학 교정학교실) ;
  • 윤태민 (연세대학교 치과대학 교정학교실) ;
  • 황충주 (연세대학교 치과대학 교정학교실, 두개안면기형 연구소, 구강과학 연구소)
  • Published : 2008.02.28

Abstract

Objective: This study was designed to analyze the primary and secondary stability characteristics of orthodontic mini-screws of tapered design when compared with the cylinder mini-screw. Methods: A total of 48 mini-screws were placed into the buccal alveolar bone of the mandible in 6 male beagle dogs. Comparison was made between tapered and cylinder type mini-screws (Biomaterials Korea, Seoul, Korea). Maximum insertion torque (MIT) was measured using a torque sensor (Mark-10, MGT 50, USA) during installation, and maximum removal torque (MRT) was recorded after 3 and 12 weeks of loading. Results: Taper mini-screws showed a higher MIT value of 22.3 Ncm compared with cylinder mini-screw showing 13.6 Ncm (p < 0.001). The MRT of the taper mini-screw showed a significantly higher value of 9.1 Ncm than those of cylinder mini-screw of 5.7 Ncm at 3-weeks after installation (p < 0.05). However, there was no difference in the MRT value between the taper and cylinder mini-screws at 12 weeks of loading. Conclusions: These results showed that the high insertion torque of the taper mini-screw design increases initial stability until 3 weeks of loading, but does not have any effect on the secondary stability at 12 weeks of loading.

교정용 미니스크류의 원추 형태가 식립 후 시기별 안정성에 미치는 영향을 알아보기 위해, 시기별 제거 토오크 및 동요도와 조직시편분석을 시행하였다. 성견 6마리의 하악 협측골에 원통형과 원추형 교정용 미니스크류 (Biomaterials Korea, Seoul, Korea) 48개를 식립하고, 식립 시 식립 토오크와 동요도를 측정하고 3주, 12주 동안 교정력을 부여한 후, 제거 시 제거 토오크와 동요도를 측정하였다. 식립 토오크는 원통형 미니스크류에서 13.6 Ncm, 원추형 미니스크류에서 22.3 Ncm 로 원추형 미니스크류에서 높은 식립 토오크가 측정되었다 (p < 0.001). 식립 3주째 제거 토오크는 원통형 미니스크류에서 5.7 Ncm, 원추형 미니스크류에서 9.1 Ncm 로 유의한 차이가 관찰되었다 (p < 0.05). 식립 12주째 원추형 미니스크류의 제거 토오크는 3.6 Ncm 로 유의하게 감소하여 (p < 0.05) 원통형 미니 스크류의 4.2 Ncm 와 유의한 차이를 보이지 않았다. 이상의 결과로 미니스크류의 원추 구조는 식립 토오크를 유의하게 증가시켜 식립 후 3주간 안정성에 도움이 되었으나, 12주 후 안정성에 있어서는 원통형 미니스크류와 유사하였음을 시사한다.

Keywords

References

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