Torque
Pronunciation: TORK
In orthodontics, the rotational force applied to a tooth root in the labiolingual or buccolingual plane, controlling the axial inclination of the tooth.
Full Definition
Torque in orthodontics specifically describes the third-order movement of a tooth — tipping the root labially or lingually while the crown may remain relatively stationary. It is expressed in degrees and is built into bracket prescriptions (e.g., the MBT, Roth, or Andrews prescriptions). Editors must appreciate that this is a highly specific clinical usage distinct from the everyday mechanical meaning (a rotational force). In orthodontic manuscripts and case reports, torque values and directions (positive/negative, lingual/labial) must be accurately reproduced.
Usage
Usage note: In orthodontic documents, 'torque' always refers to the labiolingual inclination of the tooth root, not a general rotational force. Distinguish from 'rotation' (movement of the tooth around its long axis) and 'angulation' (mesiodistal tip of the crown).
In Context
- "Positive torque was prescribed for the upper central incisors to achieve correct labial root inclination." — Bracket prescription specification
- "Loss of upper incisor torque was identified as the cause of an inadequate overjet reduction." — Orthodontic case debrief report