The moment to force ratio (M/F) for bodily movement of a tooth is ideally 8:10. This ratio ensures that the force applied moves the tooth bodily without tipping. A lower M/F ratio results in uncontrolled tipping, whereas a higher ratio causes root movement or torque. For bodily movement, the moment generated by the force must counteract the rotational tendency, requiring a higher moment relative to the force, hence the ratio close to 0.8 (8:10). This balance allows uniform displacement of both the crown and root simultaneously. Proper control of this ratio is critical during orthodontic treatment for effective and safe tooth movement.

Reference: Proffit, Contemporary Orthodontics, 6th Edition.