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What is the proper protocol for tightening, removing, and reusing Passivity Plus™ screws?

Proper screw handling is essential to activating the Passivity Plus™ self-adjusting mechanism and preserving its passive fit. The protocol covers three phases: tightening sequence during seating, removal after torquing, and guidance on screw reuse.

Recommended Screw Tightening Sequence

The self-adjusting mechanism only works if all screws are partially engaged before any are fully torqued. Locking one screw early traps the cap before it can compensate.

Step Action Purpose
1. Initial engagement Hand-start each screw with 2-3 turns Engage threads without restricting movement
2. Hold off on full torque Leave all screws partially engaged Allow free movement of all caps
3. Allow self-adjustment Give the pivotable caps time to find their compensated positions Let the system passively settle
4. Progressive tightening Use a cross-pattern to gradually tighten all screws Distribute force evenly
5. Final torque Torque each screw to 25 N·cm in an alternating pattern Activate the cold weld and lock the adjusted position

Critical: Do not torque individual screws to 25 N·cm before all screws are partially engaged. The self-adjusting mechanism needs freedom to compensate before it is locked.

Screw Removal After Torquing

Despite the cold weld, removal is straightforward and predictable:

  • Use a standard screwdriver to loosen
  • Initial resistance is approximately 15-20% higher than a conventional screw (this is the cold weld releasing)
  • Once past the cold weld zone, the screw backs out easily
  • The screw may remain attached to the screwdriver tip, which is normal

The "cold weld" is a mechanical friction lock, not a permanent metallurgical bond. It releases predictably when loosened.

Is the Screw Single-Use?

Perspective Guidance
Official regulatory The screw is indicated for single-use per standard regulatory requirements
Practical durability The screw design can withstand 5-10 uses without structural damage. The cold weld distributes stress to the screw body rather than the threads, and resets each time the screw is loosened
Clinical recommendation Use professional judgment, inspect before any reuse, and replace when in doubt

Before reusing, inspect for:

  • Bending or visible deformation
  • Scratches or surface damage
  • Thread damage
  • Any visible wear

When in doubt, use a new screw.

Additional Resources

For more information concerning Passivity Plus:

 

Contact Information

For help implementing Passivity Plus to your next case, contact ROE Dental Laboratory: