Which component of a fixed orthodontic appliance is used to hold the archwire in place on molar teeth?

The component of a fixed orthodontic appliance used to hold the archwire in place on molar teeth is the tube. Tubes are typically bonded or welded to the surface of the molar teeth and feature a slot that accommodates the archwire. This secure placement is crucial as it helps to facilitate the proper movement of the teeth during orthodontic treatment.

In contrast, brackets, while essential components of fixed orthodontic appliances, are primarily associated with the anterior and premolar teeth, allowing for the attachment of the archwire but not specifically for the molars. Alastik (modules) refer to the elastic ligatures that attach the archwire to the brackets but do not serve the same function as tubes in securing the wire at the back of the mouth. Elastic may refer to the latter but is also typically related to the movement of teeth and does not directly hold the archwire in place on the molars. Thus, the tube serves a specific and critical role in the overall assembly of orthodontic appliances, especially concerning the molars.