How to bond Zirconia crowns and Zirconia resin bonded bridges

As you probably realize, Zirconia, though porcelain appearing, is not a ceramic - it is a metal oxide. As such, we may need a different protocol for bonding Zirconia crowns and Zirconia Resin Bonded Bridges than we would use for materials like Emax (lithium disilicate). The question that you need to ask yourself, do you want to cement the crown, or resin-bond the crown.

If I want/need to bond the zirconia, the technique that I use is based on Markus Blatz's research and his technique that he refers to as the APC concept:

The key to long term bonding of zirconia is the use of a primer that contains 10-MDP. The two cements that I like to use currently are Panavia V (Kurrary) and SpeedCem plus (Ivoclar). With Panavia, the 10-MDP molecule is integrated in their primer. With SpeedCem Plus, the MDP is incorporated in the self-etching cement itself.

After anesthesia, provisional removal and zirconia restoration try in, this is my protocol with Panavia V:

1. Clean crown with Ivoclean (Ivoclar) to remove proteins and bad stuff from saliva/bleeding that can limit bond, rinse and dry *DO NOT USE PHOSPHORIC ACID TO CLEAN ZIRCONIA

2. Place one coat of 'crown primer' carefully in intaglio of crown. Be careful not to paint primer beyond the margins as the cement will bond to areas where the zirconia has been primed and clean up will be more difficult

3. Air thin and set to the side

1. Isolate and clean the prep with either pumice or, more ideally, 50 micron aluminum oxide with air abrasion.

2. If enamel is present and substantial, I'll etch only the enamel with phosphoric acid for 15-30 seconds, rinse and dry completely (do not etch the dentin).

3. Place multiple coats of the 'tooth adhesive', air thin for 15 -20 seconds - do NOT light cure.

4. Place a thin layer of Panavia V cement (I like the universal shade), place crown.

5. With pressure on the crown, light cure each line angle for literally 3 seconds, and only 3 seconds. I'll cure ML, DL, MB, DB for molars, but for bicuspids or anteriors I'll cure 3 seconds facial and lingual.

6. At 3 second cure, you can use an explorer to easily peel away the initial cured Panavia.

7. With the assistant using pressure to hold the crown in place, I use Glide to gently floss thru the contacts, being careful to not cause bleeding.

8. Place glycerine around margins to reduce oxygen inhibited layer (Oxygone, Cosmedent).

9. Final light cure 20 seconds per line angle.

10. Scale and remove any excess material.

With Ivoclar's SpeedCem, this is a self etching cement, so no tooth adhesive is necessary. This is more like a traditional cement, so the technique is less sensitive. Clean the intaglio of the crown with Ivoclean, isolate the tooth (this is critical - no bleeding gums), and load the cement. With the optional light cure activation, you can tack cure the cement after seating. Light cure for just a couple seconds per line angle, remove excess with an explorer and floss thru the contacts, and then allow the cement to set.

Resin bonded cements that utilize self-etch adhesive, like Panavia V, are going to give the strongest bond strength, and are especially critical for short clinical crowns (i.e. 2nd molars). So, while the technique is more complicated, it is the technique that I most often use (and follows the APC protocol). The self adhesive resin cements, like SpeedCem Plus, can be used if the preps are more profound, have gently tapered axial walls, and longer preps.

But, please understand, there are several great resin cements on the market - these two products are the ones that I consider for zirconia restorations. If you are having success with the cement that you are using, then continue on. But be sure that you are clear if you are bonding the zirconia (APC protocol) or cementing.

Alright, that was a long response for a seemingly simple question, but I hope that the information was helpful for you in your clinical practice.

Yours for better dentistry,