Final answer:
Orthodontic separators are used before placing braces to create space for the orthodontic bands that are part of the braces. They are not typically used for retainers, headgear, or dentures. The force applied by braces aligns the teeth properly.
Step-by-step explanation:
The use of orthodontic separators is often necessary before placing braces on teeth. Orthodontic separators, or spacers, are small devices used to create space between teeth. This space is required for the proper fitting and alignment of an orthodontic band that is part of the braces system. Braces apply forces to teeth to realign them through a wire that tensions the teeth. For example, as shown in Figure 4.37, the force applied to a protruding tooth by the wire (Fapp) is oriented straight towards the back of the mouth to correct alignment.