Final answer:
Separators or spacers are placed about a week before orthodontic bands to create space between teeth for the bands to fit properly. They are vital for the realignment process depicted in braces, applying necessary tension.
Step-by-step explanation:
The orthodontic device that is placed approximately 1 week before the placement of orthodontic bands is called a separator or spacers. These devices are intended to create a small gap between the teeth so that the orthodontic bands can fit around the teeth properly when they are subsequently placed. Separators are typically made of rubber or metal and are inserted between the molars to push the teeth apart gently. This preparation is an essential step in the process of applying forces to teeth to realign them, as seen in Figure 4.37, where braces apply tension to correct the positioning of a protruding tooth.