This study was done to evaluate the changes of torque value according to bracket height. 6.1 mandibular first molar samples were selected and estimated the torque value with computer system under the condition that bracket or tube was attached to the buccal surface of the tooth at the vertical heights of ;3.0, 3. 5, 4. C, 4.5㎜ from cusp tip which has been used as the reference heights, clinically.
The following results were obtained;
1. The torque values at the bracket height of 3.0, 3.5, 4.0, 4.5㎜ were -31.0876, -26.7557, -22.6041, -17.8878 degree, respectively.
2. The changes of mean torque value according to bracket height of 0. 5㎜ decrease or increase were 4~5 degree, approximately.
3. The preadjusted torque values of bracket or tube in mandibular first molar as -27, -22 degree were found to fit those of 3.5, 4.0㎜ bracket height, respecitively.
4. The torque values need individual adjustment due to high variance as attached bracket height and tooth morphology.
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