Friction, Binding And Notching Flashcards
Static Friction
Force Required to initiate movement
Kinetic Force
Force that resists motion
What is the main obstacle?
To overcome resistance to sliding
What is friction proportional to…
The force acting in contact and the area of contact
What is force the force also effected by?
•the surface of interference:
•rough/smoothness
•chemically reactive/inert
•modified by lubricants
What causes the resistance to sliding?
•Friction
•Binding
•Notching
What is the contact angle?
Where the corner of the bracket meets the archwire
What happens at the critical angle?
• Tooth moves along the wire
•tips until corner of the bracket contact the wire
• then a moment is generated and prevents further tipping
What effects the size of the critical angle?
The size of the bracket
- wider brackets= smaller angles
What happens when the resistance to sliding increases?
Binding overwhelms friction
What does Binding eventually lead to..
Notching and sliding stops
What is Notching?
Interaction of the wire and bracket material
Different wires show different effects
Stainless Steel wires and notching…
•more obvious due to sharper edges
Niti wires and notching
•less obvious due to blurred lines
How do you minimise resistance to sliding
•avoid notching
•eliminate binding
•minimise friction
