Which of the following arch wire types is least likely to maintain tooth position during final adjustments?

Round wire is least likely to maintain tooth position during final adjustments because it provides minimal friction and resistance against the brackets. Its shape allows for more movement and less control over the positioning of the teeth compared to other arch wire types. This is particularly important during the final phases of orthodontic treatment when precise positioning is critical for achieving optimal alignment.

In contrast, rectangular and square wires are designed to engage the brackets more effectively, providing greater friction and control, which aids in holding teeth in place during adjustments. Nickel titanium wire, known for its unique qualities, maintains its shape and exerts a continuous force on teeth, making it effective during tooth movement. The properties of round wire make it more suited for initial movement phases rather than fine-tuning positions during the final adjustments of orthodontic treatment.