Monday, March 5, 2012

Intra-oral Luting of Implant Verification Jig and Pick-up Impression for Mandibular Hybrid

  • Label each individual GC pattern covered direct impression transfer post with it's appropriate location.
  • Hand tighten each post onto the appropriate implant.  
    • Ensure the GC pattern resin is not touching when in place.  
  • If margins are subgingival and seating verification cannot be visualized, peri-apical radiographs may be necessary to verify complete seating of the transfer posts.

  • Isolate the area from saliva using cotton rolls and gauze.  
  • Brush bead the gaps between each direct transfer post with GC pattern resin.  
    • Ensure the GC pattern resin fills the space entirely.  
  • Allow, GC pattern resin to polymerize for 10 minutes.

  • Loosen impression screws and remove from the patient's mouth.
  • Place the verification jig on the original cast and verify passivity of fit.  
    • If the jig seats completely and passively on the preliminary cast no verification jig pick-up impression is needed.
    • If the jig does not seat passively proceed with the custom tray verification jig pick-up impression.

  • Re-attach the verification jig to the implants in the patient's mouth and hand tighten.
  • Verify fit of the custom tray over the verification jig while in the mouth
    • Make adjustments to the tray if necessary
  • Apply adhesive to the inner surface of the tray.
  • Isolate the verification jig in the mouth from saliva.
  • Apply light body polyvinylsilosane around the verification jig.
  • Apply heavy body polyvinylsiloxane to the internal aspect of the tray simultaneously.
  • Insert into the patient's mouth and wipe away excess from the screw access holes.  Have the pooch and smile to border mold
  • Leave impression material in place with patient relaxed for 5 minutes.

Sunday, March 4, 2012

Verification Jig Fabrication for Mandibular Hybrid Prosthesis

Place open tray impression transfer posts on the preliminary implant analog cast.  Tighten to light hand tightening (tighten to how you will tighten in the mouth)

Apply GC pattern resin (fast setting low shrinkage dental resin) using the brush beading technique to all impression transfer posts.  Keep the resin above the connection of the impression post and the implant/abutment.

Apply sufficient GC pattern resin to connect the direct transfer impression posts together.  Provide sufficient bulk of material to allow maximal rigidity of the resin material.  

Using a thin diamond disk, section the GC pattern resin index between each direct transfer impression post.  Allow resin to set for a full 24 hrs.

Fabricate a custom tray for a possible splinted implant verification jig over-impression.
  • Relieve mandibular cast and verification jig with one layer of softened base plate wax.
  • Add an additional layer of softened base plate wax to the implant verification jig location.
  • Ensure the impression screws are poking through the wax occlusally.
  • Apply separating medium to the wax (vasoline)
  • Adapt Triad Tru-Tray over the wax and trim to just past the wax. Cure for 1 minute in the Triad Curing unit.
  • Ensure the screws are slightly poking through the triad occlusally.
  • Remove the wax from the intaglio surface while still soft and place back into the Triad curing unit for an additional 6-8 minutes.
  • Trim and smoooth tray
  • Ensure the direct transfer impression screws are passing passively through the custom tray.

Preliminary Mandibular Hybrid Open Tray Implant Impression

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)