Thinking of doing a cement implant crown?
Cement implant crown is one of the two major ways we deliver the crown. To see comparisons of cement vs screw retained check our post with the research.
Cement implant crown steps and tips
I will just list the most important key points and then later go into them in more detail.
- Do NOT use a methacrylate cement.
- Use a custom abutment or modify a stock abutment so that your margins are above the gingiva in all non esthetic areas.
- Make the area right below the margin on the abutment convex so cement gets pushed out and away. Sancho-Puchades 2017 shows this and it is my thought that this makes easier to clean up as well.
- Wait at least 4 weeks for peri-implant tissue to heal.
- Allow for a venting area either in the lingual as Zaugg shows or at least leave a gap in your abutment access above your PTFE tape.
- Do not overfill the crown with cement and use an abutment analog to extrude extra cement before seating.
Design issues to help cement implant crowns.
Get a custom abutment (or stock for the rare case that the margins are above the tissue) and have the lab leave all margins but the esthetically critical areas ABOVE the gum line. In esthetic areas have them place the margin just barley below the gum line. Rather than burying the lingual and IP margins, simply leave them supragingival. To aid in seating your abutment you can use a seating jig. Furthermore, your lab can make the margin of the abutment slightly bulbous or convex right below the margin. This will help guide the excess cement out away from areas that cement may get trapped.
Technique issues to help cement implant crowns.
Pack your plumbers tape in the hole but leave room for excess cement to flow into access hole. The tape is only there to protect the screw head from damage, therefore you do not need much. There is no need to fill the whole implant chamber with anything, because that leaves nowhere for excess cement to go but down the side of the abutment. Furthermore, research shows leaving 2mm space deceases the amount of excess cement.
Use a small amount of cement. Most techniques involve placing one layer of plumbers tape inside the crown and seating it on the abutment, then making a mold of the interior of the crown with acrylic or impression material. The next step you remove the tape, place cement, and seat the crown on your duplicate mold to remove excess cement before seating on the torqued abutment.
Finally, if you really want to be anal, you can pack a small cord around the abutment and remove after cementing OR if tissue very tight can try floss like this
|Lane photo from this thread|
Picking the right cement to cement implant crown
Use the right cement! A radio-opaque cement is preferable. Most “implant cements” sold today are radio-lucent resin, which are the worst choice you could pick. I personally use ceramir, which is a bioactive cement that should be more kind to the tissue. Do NOT use a resin (methacrylate) cement!!! Korsch has shown they are more likely to result in excess cement, are more likely to cause inflammation, and even cause inflammation if there is NO excess. Later Korsch found that changing the cement from resin to ZOE reduces BOP by 65%.
Cement implant crown without cement sepsis
One of the biggest problems we see emerging with dental implants is cement sepsis. I feel the primary causes are
- Lack of use of a custom abutment causing the margin to be sub-gingival (Usually done so the doc can save the cost of having a custom abutment with proper dimensions made)
- Implant companies selling resin cement as “implant cement”. Of all the cements available to a dentist, I think resin is the worst choice for implants. Not sure why the industry went down this path. Resin cement is radio-lucent so can’t see excess on xray AND it sticks to Ti extremely well so hard to remove excess AND it flows too well (low viscosity). Bone is porous and the resin will literally flow right down the side of an implant.
- Inexperience of the dentist placing the crown. (I think the vast majority of cases of implant sepsis are caused by young and/or inexperienced implant dentists or careless dentists that haven’t been paying attention to the dental industry research or lecturers)
So let’s fix this problem!
Here are my favorite three solutions to cement implant crown in no particular order