Implant Crown Impression and Cementation

Check which the implant has been placed: Bicon, Tatum, submerged SM), UF or IBS and whether a provisional is cemented.  Prepare an appropriate abutment screw driver.  For SM implant, use a 1.7 Torx driver to tighten the abutment; for UF and IBS use 1.2 hex driver to tighten the abutment

Check whether PA is updated or not.  When should a new one be taken?

After removing the temporary crown if present, use the reduction rings 1 mm and 2 mm to check the occlusal clearance

If the clearance is > 2 mm, change to a longer abutment so that the crown is less likely dislodged.  Prepare spare abutments every time

Apply Cetacaine to the gingival sulcus

Insert the 000 and 00 cords with the cord packer.  If the margin is too low or too high, change the abutment

Take out a high speed hand piece if necessary

If we decide to fabricate a cemented crown, follow Step A; screw type crown, jump to Step B

Step A

Use the Cavitron to remove Cavit and cotton pellets in the center of the cemented abutment

Use a machine hex driver and a calibrated torque wrench to tighten to 30 Ncm for DIO, 25 Ncm for IBS. Rest for 10 min.  Turn to 35 Ncm for DIO and 30 Ncm for IBS.  This precaution is to reduce chance of abutment screw loosening

Insert the plumber tape into the center of the cemented or pair abutment until it is filled. If there is not enough tape, use the Cavit to close the access of the abutment.

Use a wet cotton pellet to clean up if Cavit is applied

As to Tatum unipost, use Ketac cement for short (3 mm), small diameter one; a resin cement for angled one

Step B

Try in impression tray

Remove the larger cord

Take PVS impression; check whether the impression is good or not.  If not, prepare for the second impression.

Choose shades for the crown and obtain consent from the patient.  Take photos if needed.  Place shade guide(s) as close as possible to the teeth concerned.  Camera is to be placed equal distance to the guides and the teeth just mentioned

Write down patient’s name and shades in prescription paper.  Check a proper material for the crown.  Particularly make note whether screw type crown is going to be fabricated: access hole on the cingulum or the middle of occlusal surface

Make a temporary crown or reline and apply temporary cement

Remove excess cement, including using floss

Let the patient read temporary crown precaution

Send the case to the lab

Before each cementation, check which type of crown is fabricated: cemented or screw-type on the note or lab box

For the latter, try in the crown for proximal and occlusal contact as usual.  Make adjustment if necessary

Remove Cavit and place cotton pellet loosely in the void in the abutment and crown access

Apply sufficient amount of cement, remove excess cement from the crown channel while the cement is setting and wait for complete cement setting.

Check proximal and occlusal contact again

Remove cotton pellet (prepare peeso bur), unscrew crown/abutment complex and remove excess cement

Follow step 2 of Step A

Check proximal and occlusal contact again

Plumber tape or cotton pellet loosely; occlusal composite (flowable for anterior teeth); check occlusion

Assistants

Xin Wei, DDS, PhD, MS 1st edition 08/21/2016, last revision 08/28/2016