Two (15 by 3,75 mm) MkII NobelBiocare implants were placed. Following soft tissue and papilla enhancement, the implants were uncovered. Patient is ready for impression. Tools needed are: 1 hex screwdriver, 1 slotted screwdriver and 2 impression copings (furnished by our office).
A sterile kit is provided by our office to the the general dentist office (from left to right) it includes a hex screwdriver, the impression copings and a slotted screwdriver. Impression copings are available in NP (narrow platform), RP (regular platform) and WP (wide platform). Some general dentists prefer to see their patients at step 12. In this case, we will be glad to perform Step 3 to 6 in our office.
Following the removal of the healing abutments (with the hex screwdriver), the impression copings are inserted by hand on the the implant. The screw is tightened by hand.
An intraoral radiograph must be taken to verify that the copings were properly inserted. Watch for gaps between the implant platform and the impression coping.
A perforated custom tray is tried. We recommend that you prepare a larger perforation than appears necessary.
We recommend that you block the undercuts (pontics...) before the impression. We also recommend that you place extra handles (small) on the sides of the tray.
The impression is taken as follows: 1) use a hard material such as Impregum. 2) do not place retracting cord. 3) eject the impression material with a syringe around the coping. 4) place the tray in place and immediately remove the excess of material to expose the screw heads. 5) after setting, untighten the screws and lift them until they stop. 6) remove the tray . 7) send the tray to the lab. Do not pour the impression.
The Lab will process a Titanium Procera abutment. The abutments are waxed up, then scanned. The scan is transmitted to NobelBiocare in Sweden where the abutments are machined automatically. The abutment are then delivered to the lab, where the provisional crowns are made. THE ABUTMENTS AND TEMPORARY CROWNS ARE DELIVERED IN OUR OFFICE.
Sterile abutments and gold screws are placed using a "star" shaped screwdriver. this step does not require usually local anesthesia.
An intraoral radiograph is taken to verify the seating of the abutments.
The gold screws are tightened using a torquing device. Notice the usage of an antitorque device. The torque can therefore be applied on the screw and not the implant. We use a torque value of 20 Ncm for Narrow Platform (NP), 32 Ncm for Regular Platform (RP) and 45 Ncm for Wide Platform (WP) implants.
The chimney of the abutments are filled with cotton mixed with antibiotic ointment and closed with Cavit. The temporary crowns (as shown in picture) are then temporarily cemented with TempBond.
The patient is referred back to the general dentist for ceramic/metal crowns one month later.
Guideline for margins: We recommend the lab places the margins of the crowns: supra-gingivally in non visible areas and slightly sub-gingivally in visible areas. If a metal margin is visible in a esthetic area, we will remove the abutment for you and have the lab drop the margin.
The Impression technique for this type of implant abutments is identical as the impression technique for teeth. Supra-gingival margin don't require the placement of a retraction cord. Sub-gingival margins require the placement of a retraction cord. We recommend that you leave the cord during the impression to prevent the impression material to migrate sub-gingivally. Remove the cord following the impression.
Cementation: Single crowns should be temporary or permanently cemented (NobelBiocare recommends Zinc Phosphate cement for permanent cement). If you are splinting crowns, we are recommending temporary cement. We recommend also that you leave a cord during the cementation to prevent the cement to migrate sub-gingivally. Remove the cord following the cementation.
General Dentist: Dr James Bright,
Newport Beach.
Laboratory technician: Jim Wehrman,
Nordent Lab, Long Beach.
Surgeon: Dr Bernard Gantes
All this material is copyrighted and cannot be reproduced nor used for any purpose without the authorization of Drs Gantes and Yamada