Overview
Open tray, or pick-up, dental impression technique is the only acceptable method for multi-implant dental full arch cases. Unlike closed tray technique where copings return to the mouth after impression removal, open tray copings remain embedded in the impression material, maintaining their precise spatial relationships during analog attachment.
What You'll Need
- Open tray impression copings for your dental implant system
- Custom impression tray with access holes for each coping
- Rigorous splinting system (resin with section-relute or metal jig)
- Polyvinyl siloxane or polyether impression material
- Tray adhesive compatible with your impression material
- Hex drivers and calibrated torque wrench
Step-by-Step
Understand Why Open Tray Is Essential
Closed tray technique requires copings to retract through set impression material, then reseat into their impressions. With four or more implants, these errors compound to produce dental frameworks that cannot seat passively.
Design the Custom Tray
Fabricate an acrylic custom tray from a preliminary impression. Create access holes over each dental implant position (typically 8-10mm diameter). Verify adequate material thickness for rigidity.
Try-In and Adjust
Seat the custom tray over connected impression copings before splinting. Verify that each hole aligns with its coping and provides adequate clearance.
Seat and Torque Impression Copings
Thread impression copings onto each implant, ensuring anti-rotational feature engagement. Hand-tighten, then apply specified torque.
Establish Rigid Splinting
Connect all copings with rigid splinting material. For resin technique, apply pattern resin over floss scaffold, cure completely, section between each coping pair, and relute. For metal technique, assemble prefabricated links.
Apply Tray Adhesive
Paint tray adhesive on all internal surfaces and allow to dry per manufacturer instructions.
Inject Light-Body Material
Syringe light-body impression material around each coping, ensuring complete coverage of the coping-implant interface.
Load and Seat the Tray
Fill the custom tray with heavy-body impression material. Seat with firm, even pressure. Verify each coping screw head is accessible.
Unscrew Through Access Holes
Once material is fully set, unscrew each impression coping through the tray access holes. Break torque smoothly.
Remove and Verify
Lift the tray straight up. All copings should remain embedded and rigidly connected. Inspect for tears, voids, or pulls.
Tips & Best Practices
- Create a tray with excess height to ensure access hole positioning doesn't compromise material thickness
- Use guide pins during tray fabrication to precisely locate access holes
- Allow 30 seconds beyond manufacturer setting time before unscrewing
- Photograph the completed impression for dental laboratory reference
Common Mistakes to Avoid
Inadequate access hole size
Holes must accommodate both coping and hex driver. Restrictive holes force angled driver engagement, creating rotational force.
Flexible or thin custom trays
The tray must resist removal forces without distorting. Inadequate rigidity allows tray deformation.
Premature screw removal
Beginning unscrewing before impression material is fully set allows coping movement within still-plastic material.