Which component of a fixed orthodontic system is placed on the tooth at a concrete distance from the cutting edge?

Which component of a fixed orthodontic system is placed on the tooth at a concrete distance from the cutting edge?

• A. Ligatures
• B. Spiral spring
• C. Brackets
• D. Button

Answer: (C)

In fixed orthodontics, brackets are bonded to each tooth at a specific height from the cutting edge (the incisal or occlusal edge) of the tooth. This precise vertical placement is essential because it sets the height of the bracket slot relative to the tooth’s center of resistance, so the archwire delivers forces in the intended directions for tipping, torque, and vertical movements. If the bracket is placed too high or too low, the lever arms change and the tooth’s movement becomes unpredictable, potentially causing improper occlusion or unwanted excursions. Other components don’t require a standardized distance from the cutting edge. Ligatures simply tie the archwire to the bracket and don’t define where on the tooth to sit relative to the edge. A spiral spring is an auxiliary between teeth to create or close space and isn’t bonded to the tooth at a fixed incisal distance. A button can be bonded to a tooth to serve as an attachment for elastics or other mechanics, but its position is function-driven rather than defined by a universal distance from the edge.

In fixed orthodontics, brackets are bonded to each tooth at a specific height from the cutting edge (the incisal or occlusal edge) of the tooth. This precise vertical placement is essential because it sets the height of the bracket slot relative to the tooth’s center of resistance, so the archwire delivers forces in the intended directions for tipping, torque, and vertical movements. If the bracket is placed too high or too low, the lever arms change and the tooth’s movement becomes unpredictable, potentially causing improper occlusion or unwanted excursions.

Other components don’t require a standardized distance from the cutting edge. Ligatures simply tie the archwire to the bracket and don’t define where on the tooth to sit relative to the edge. A spiral spring is an auxiliary between teeth to create or close space and isn’t bonded to the tooth at a fixed incisal distance. A button can be bonded to a tooth to serve as an attachment for elastics or other mechanics, but its position is function-driven rather than defined by a universal distance from the edge.