Which characteristic describes fixed orthodontic appliances?

Which characteristic describes fixed orthodontic appliances?

• A. Functional action
• B. Combined action
• C. Mechanical action
• D. Apparatus with the occlusal overlap

Answer: (C)

The main idea is that fixed orthodontic appliances move teeth through mechanical action. Brackets are bonded to each tooth, an archwire runs through those brackets, and ligatures or clips hold the wire in place. The wire’s shape and tension apply controlled, continuous forces that tip, rotate, push, or pull teeth over time, driving tooth movement through physical forces and the resulting bone remodeling. This distinguishes fixed appliances from functional options, where changes in bite or muscle function contribute to movement, and from descriptions that don’t refer to the force mechanism. The notion of an appliance defined by occlusal overlap isn’t the defining feature of fixed systems, since fixed appliances operate via the bracket–wire force system regardless of how the teeth meet at the bite.

The main idea is that fixed orthodontic appliances move teeth through mechanical action. Brackets are bonded to each tooth, an archwire runs through those brackets, and ligatures or clips hold the wire in place. The wire’s shape and tension apply controlled, continuous forces that tip, rotate, push, or pull teeth over time, driving tooth movement through physical forces and the resulting bone remodeling.

This distinguishes fixed appliances from functional options, where changes in bite or muscle function contribute to movement, and from descriptions that don’t refer to the force mechanism. The notion of an appliance defined by occlusal overlap isn’t the defining feature of fixed systems, since fixed appliances operate via the bracket–wire force system regardless of how the teeth meet at the bite.