Conventional implant impressions can be made with an open tray (pick-up) or closed tray (transfer) technique,
1
,2
with the open tray technique recommended for complete-arch implant impression because of its greater accuracy.3
However, stabilization of the impression copings is essential to prevent micromovement when it is detached from the implant fixture or during placement of the implant laboratory analog.4
Rigid impression copings are essential for the accurate transfer of their 3D position to the definitive cast. Dental floss or orthodontic elastomeric chain stabilized with resin is typically used to splint the open tray impression copings.4
,5
However, these techniques have limitations.6
The purpose of this article was to present a straightforward procedure to splint open tray impression copings for complete-arch implant impressions by using cast metal sprues and autopolymerizing resin.Technique
- 1.Remove the transmucosal abutments (Healing abutment [AO]; Megagen) after evaluating satisfactory healing of peri-implant soft tissue. Place open tray impression copings (Pick up coping [AO]; Megagen) with a 10-Ncm torque (Fig. 1) and make periapical radiographs to verify proper seating of the impression copings.
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Figure 1Open tray impression copings placed with 10-Ncm torque. - 2.Measure the distance between the surface of impression copings with calipers (Divider; Camlin Kokuyo) (Fig. 2A). Mark these distances on sprues (Fig. 2B) with a permanent marker (Permanent marker; Camlin Kokuyo).
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Figure 2A, Distance measured between open tray impression copings with calipers. B, Measured distance marked on metal sprue with permanent marker. C, Metal sprue sectioned to desired length with disk. D, Metal sprue segment verified intraorally. - 3.Section the sprue to the desired length with a disk (Separating disc; Falcon Abrasive Co, Ltd) (Fig. 2C) and verify its fit intraorally (Fig. 2D). If required, adjust the metal sprue segment with a disk. Apply cyanoacrylate resin adhesive (Fevikwik gel; Pidilite) on both the ends of metal sprue segment (Fig. 3A) and stabilize it to the surface of open tray impression copings (Fig. 3B).
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Figure 3A, Cyanoacrylate resin adhesive applied at both ends of metal sprue segment. B, Metal sprue segment stabilized to impression coping surface by using cyanoacrylate resin adhesive. C, Metal sprue segment reinforced to impression coping surface with autopolymerizing resin. D, Impression copings stabilized by using metal sprue segment and autopolymerizing resin. - 4.Reinforce the attachment of both ends of metal sprue segment to the surface of impression copings with autopolymerizing resin (Pattern resin; GC Corp) (Fig. 3C). Apply autopolymerizing resin in small multiple increments to minimize shrinkage.7Repeat the procedure to connect and stabilize all open tray impression copings (Fig. 3D).
- 5.Intraorally, inject low-viscosity impression material (Flexceed light body; GC Corp) around the open tray impression copings and metal sprue segment. Fill the stock tray with a high-viscosity impression material (Flexceed putty type; GC Corp) and seat intraorally (Fig. 4).
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Figure 4Intaglio surface of definitive impression.
References
- Impression techniques for implant dentistry.Br Dent J. 2006; 201: 429-432
- Comparative study of dimensional accuracy in three dental implant impression techniques: open tray, closed tray with impression coping, and snap cap.J Contemp Dent Pract. 2018; 19: 974-981
- Accuracy of complete- arch implant impression made with occlusal registration material.J Prosthet Dent. 2019; 123: 143-148
- Orthodontic elastomeric chain as an alternative to dental floss for splinting implant impression copings for complete-arch implant impressions.J Prosthet Dent. 2020; 123: 188-189
- Conventional open-tray impression versus intra oral digital scan for implant-level complete-arch impression.J Prosthet Dent. 2019; 122: 543-549
- Orthodontic wire loop for engaging dental floss or orthodontic elastomeric chain in the open tray implant impression technique.J Prosthet Dent. 2020; 124: 500-501
- Accuracy of wax, autopolymerized, and light-polymerized resin pattern materials.J Prosthodont. 1996; 5: 201-205
Article info
Publication history
Published online: October 15, 2020
Identification
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© 2020 by the Editorial Council for the Journal of Prosthetic Dentistry.
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