Friction significantly impacts space closure efficiency in orthodontics. Bracket material, archwire selection, slot clearance, and mechanical factors like binding and notching all influence sliding mechanics.
Factors Affecting Space Closure
1. Surface Roughness and Bracket Material
Ceramic brackets have greater surface roughness than stainless steel brackets.
2. Clearance Between the Archwire and Slot
Slot clearance impacts friction levels, as tighter tolerances lead to increased friction.
LightForce brackets are designed for accuracy and with less clearance than stock brackets for a given archwire-bracket combination.
3. Archwire Binding and Notching
Binding and notching occur due to tooth tipping and archwire deflections during space closure.
These interactions cause deformations in the wire that significantly impede sliding
Selecting the Right Archwire for Sliding Mechanics
Choosing the right archwire is essential for minimizing friction and ensuring efficient space closure. The following recommendations help optimize movement based on clinical needs.
Benchtop testing of different archwire sizes and materials in LightForce brackets and tubes is as follows:
NiTi wires exhibit the least amount of friction due to their resistance to notching.
TMA wires have slightly higher friction than NiTi.
SS wires have the highest friction due to increased notching.
Benchtop Breakthroughs: Archwire Selection for Sliding Mechanics
Additional Clinical Considerations for Reducing Friction
Bracket Size
Select a bi-dimensional slot size in the LightForce Prescription form.
Larger slot sizes in the posterior allow for less friction and binding during sliding. Ex: If extracting first premolars, select a .020 slot from 3-3, and .022 slot from 5-7
Bracket Slot and Tube Maintenance
Assess brackets and tubes for calculus before space closure.
Carefully apply acid etch to slots and tubes for 30 seconds, then rinse with suction to remove plaque buildup.
Difficulty removing archwires may indicate calculus presence and should be addressed before proceeding.
Ensuring a Leveled Arch Before Space Closure
Tipped teeth and archwire deflections increase binding and notching, reducing sliding efficiency.
Ensure that leveling is complete before initiating space closure to prevent unnecessary resistance.
Archwire Adjustments for Minimizing Friction
Trim the wire distal to the first molar tube (avoid engaging the second molar tube) to minimize binding.
All tubes are wire-fit prior to shipment, so confirm the archwire has the proper clearance before placement.
Bi-dimensional wires can create more slot clearance in the posterior to reduce friction.
Techniques for Efficient Space Closure
Use of NiTi Coil Springs
Attach from the molar to a crimpable hook on the archwire anterior to the space.
This helps reduce binding caused by the tipping of canines and premolars.
Posterior Teeth Stabilization
Steel or lace-tie posterior teeth to reduce sliding friction during space closure.
Frictionless Mechanics Options
Preformed closing-loop archwires offer a convenient alternative to sliding mechanics.
Resource & Ordering
Disclaimer
The content provided in this presentation is for informational purposes only and should not be relied upon as a substitute for professional advice or guidance. Data is from internal bench testing with results on file. These statements have not been evaluated by the FDA and are not intended as diagnostic or medical advice. All treatment decisions, including archwire selection, are the responsibility of the treating provider. The content herein may be subject to copyright or intellectual property rights, and any unauthorized use or distribution is strictly prohibited.