The comparison of torque values in two types of miniscrews placed in rabbits: tapered and cylindrical shapes - Preliminary study
김형호, 정주령, 유현미, 박동성, 장인성, 경승현,
소속 상세정보
김형호 ( Kim Hyung-Ho ) - Gangnam Severance Dental Hospital Department of Orthodontics
정주령 ( Chung Choo-Ryung ) - Gangnam Severance Dental Hospital Department of Orthodontics
유현미 ( Yoo Hyun-Mi ) - Sungkyunkwan University School of Medicine Samsung Medical Center The Institute of Oral Health & Science Department of Conservative Dentistry
박동성 ( Park Dong-Sung ) - Sungkyunkwan University School of Medicine Samsung Medical Center The Institute of Oral Health & Science Department of Conservative Dentistry
장인성 ( Jang In-Sung ) - Laboratory Animal Research Center Samsung Biomedical Research Institue
경승현 ( Kyung Seung-Hyun ) - Sungkyunkwan University School of Medicine Samsung Medical Center The Institute of Oral Health & Science Department of Orthodontics
KMID : 0361920110410040280
Abstract
Objective:This study compared the stability of cylindrical miniscrews (Cy, 7 mm in length) with that of tapered miniscrews (Ta, 5 mm in length), using torque values to determine if the healing time before loading affects the stability of the miniscrew and if the insertion torque is associated with the removal torque measured after a few weeks of healing.
Methods:Ta and Cy with different thread lengths were placed in the tibias of 12 female New Zealand white rabbits (body weight: 3.0 - 3.5 kg), and the maximum insertion torque values (ITV) were measured. No orthodontic forces were applied so as to allow us to determine the pure effects of the different shapes. After 3 different healing periods (2, 4, and 6 weeks), maximum removal torque values (RTV) were measured immediately before the rabbits were sacrificed.
Results:No miniscrews were loosened. There were no significant differences in ITV or RTV between the Ta and Cy nor were there any significant differences in the ITV and RTV between the 3 groups, which had different healing periods. There was a correlation between the ITV and RTV.
Conclusions:Shorter Ta showed similar stability as Cy, as determined by torque values. This result strongly suggests that the tapered shape is more advantageous than the cylindrical shape. The RTV did not increase significantly over time. It is recommended that a miniscrew be loaded immediately; waiting a few weeks before loading should be avoided. The correlation between the ITV and RTV suggests that the ITV can be used to estimate a screw’s future stability.
키워드
Tapered shape; Torque; Miniscrew; Stability
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