Insertion and removal torques according to orthodontic mini-screw design.
- Author:
Jung Yul CHA
1
;
Tae Min YOON
;
Chung Ju HWANG
Author Information
- Publication Type:Original Article
- Keywords: Orthodontic mini-screw; Insertion torque; Removal torque
- MeSH: Animals; Dogs; Humans; Korea; Male; Mandible; Torque
- From:Korean Journal of Orthodontics 2008;38(1):5-12
- CountryRepublic of Korea
- Language:Korean
- 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.
