Once the implants are in place, healed, and healing abutment inserted...
- Make an Alginate impression with a stock tray mandible and the implants with their healing abutments in place.
- Ideally an over-extended impression should be obtained.
- Pour impression with dental stone (minimally type III).
- This cast will be used to fabricate a custom tray for an initial open tray implant impression.
- To ease in the tray fabrication process identify and mark with a pencil the location at which the of the vestibule begins to fold and mark about 1 mm superior the location of the wax relief
- Place 1 sheet of softened baseplate wax over the entire mandibular arch.
- Provides about 1.5 mm uniform relief for the impression material
- Trim the wax to about 1 mm from the fold the patient's vestibule or to the red line scribed on the cast.
- This allows room to border mold the impression tray in the patients mouth.
- Cut 3mm X 3mm relief holes in the baseplate wax over the posterior ridge area
- Soften and roll another sheet of baseplate wax and place in the area over the implant sites.
- Must be correct size to allow about 1.5 mm of impression material to encase the implant impression analogs to be captured intra-orally
- Know the size of the implant direct transfer impression posts(anterior posterior length, buccal lingual width, and gingival to screw height)
- NOTE: pay close attention to the angle of the implants and prepare accordingly
- Place separating (vasoline) medium over the entire surface of wax.
- Adapt Custom Tray Acrlyic (Triad: True-Tray) over the wax relief.
- Trim the Custom Tray Acrylic back to the fold of the vestibule or the pencil line scribed earlier
- Cure for 1 minute in the triad curing unit then remove the wax relieve
- Turn the Tray over and cure for 6-8 minutes in the triad curing unit then remove and trim and smooth extensions of the tray to the fold of the vestibule
There are 2 Ways to Access Screws of Impression post during the open tray impression technique.
1. Remove the tray material above the implants prior to the tray going into the patient's mouth
- Hand tighten implant impression transfer copings onto implants or implant tissue level abutments
- Try tray in the patient's mouth and identify any areas of over extension, adjust if needed
- Ensure tray fits passively over the implant impression transfer posts
- Place a thin layer of wax over the access site in the tray
2. Identify Screw location while in the mouth and place holes in the tray to allow access to the screws during the impression
- Hand tighten implant impression transfer copings onto implants or implant tissue level abutments
- Try tray in the patient's mouth and identify any areas of over extension, adjust if needed
- Place a thin layer of bite registration material in the tray over the implants and seat the tray in the patient's mouth
- Drill holes through the tray where ever the screws made imprints into the registration material
- Try the tray in the mouth and adjust screw access holes until screws pass through the tray passively
Polyvinyl Siloxane Impression
- Ensure tray is clean of contaminants
- Apply tray adhesive and let sit for 5-10 minutes
- Dry the patients mouth
- Apply light body PVS around the implant impression transfer posts and heavy body PVS to the tray simultaneously
- Insert filled tray into the patient's mouth and have patient pooch and smile to border mold the impression
- Allow to sit for five minutes
- Unscrew impression screws and remove impression from the patient's mouth
Attach implant lab analogs and carefully hand tighten them to the impression posts while still in the impression.
Add polyether impression material around the implants to provide a soft tissue cast on the final cast.
Box and pour impression with the lowest expansion dental stone possible (Resin Rock or Silky Rock)
