The optimal orthodontic force for moving an incisor is 20-50 grams because this range provides effective tooth movement while minimizing root resorption and patient discomfort. Forces below this range (<5-10 grams) are typically insufficient to stimulate cellular activity for remodeling, while forces above this range (>100 grams) can cause hyalinization of the periodontal ligament and damage to surrounding tissues. Maintaining forces within 20-50 grams ensures controlled, physiologic tooth movement, essential for predictable and safe orthodontic treatment outcomes.

Reference: Proffit Orthodontics, 6th Edition.