Finger springs for removable appliances are best made from stainless steel wire because it offers high stiffness, excellent formability, and good springback properties. Stainless steel provides the necessary strength and corrosion resistance for repeated activation without permanent deformation. It also maintains consistent force delivery, which is critical for effective tooth movement in removable appliances. Other materials like gold or nitinol lack the ideal balance of mechanical properties and cost-effectiveness required for finger springs. Therefore, stainless steel remains the material of choice in clinical orthodontics.

Reference: Graber’s Orthodontics, 7th Edition.