What helps to bring about movement between maxillary and mandibular arches?

The movement between the maxillary (upper) and mandibular (lower) arches is primarily facilitated by arch wires. Arch wires are used in orthodontic treatments to connect the brackets placed on the teeth. These wires provide the necessary force to shift the teeth into their desired positions, enabling proper alignment and occlusion between the upper and lower jaws. They are designed to hold the brackets in place while allowing for movement, which is critical for correcting dental misalignments.

In comparison, retainers are used primarily after orthodontic treatment to maintain the position of teeth rather than facilitating movement. Orthodontic springs, while they can provide movement to specific teeth, often serve localized purposes and do not affect the entire arch motion in the same way arch wires do. Headgear is an orthodontic appliance that helps in guiding the growth of the jaw or positioning the teeth but is not responsible for direct movement between both arches in the same manner as arch wires.