Delivering an All Ceramic Crown

This past Friday, I delivered an All Ceramic Crown on #8. . . Remember that an ACC is bonded, and so there are more steps involved with delivery than with a PFM crown. I'll do my best to walk you through everything.

 What to get from Supply and Sterilization

1. Black fit checker  (white is for a PFM)
2. Variolink II Try-in paste kit
3. Variolink II cementation kit
4. Teflon tape - 1 or 2 strips
5. Articulating paper
6. a Z100 composite kit
7. an Optragate (to hold the lips away)
8. crown and bridge tray
9. gauze and cotton rolls
10. a #12 blade and handel
11. prophy cup and pumice
    
    

 

From Your Cart

1. Curing light
2. Porcelain polishing bur block
3. composite finishing bur block
4. floss
5. red/blue pencil

Procedure

1. Take the temporary off and clean off the prep using a prophy cup and a gentle cleaning with a scaler if necessary. 
2. Try the ACC on to see if it fits. Does it seat all the way? Does it feel okay to the patient? Is it too short? If the crown is on #8, does it match the shape of #9? Are the incisal edges the same length?
3. Have the patient push on the crown with a finger while you try to get floss through the interproximal surfaces. Are the contacts good?
4. Once you have inspected the outside, its time for fit checker. On a mixing pad, dispense equal amounts of base and catalyst. For a single crown, you should need much at all. Mix with a spatula for 20 seconds or so and fill the crown to the top with it. Seat the crown and hold it there for about 1.5 minutes.
5. Remove the crown. If the fit is right, then you will not be able to see any of the crown showing through. There should be a thin uniform film of fit checker on all surfaces of the inner surface. If any part of the crown is showing thru, mark it with a red pencil, remove the fit checker, and then grind those red spots with a composite finishing flame bur (or whatever works for you). Repeat this step until the fit checker covers all inner surfaces. 
6. Once the fit of the crown is right, you can put on the Optragate:
   
7. Make sure when trying in different cements, that it is the TRY-IN paste. There are several different colors. Just pick one (maybe start with transparent), fill the crown with it and then seat it. If the color looks okay, then that will be the color you will use during final cementation. If the color looks a little off, then try in a different color paste until you find the  one that makes the crown look the most natural.
8. If you know that the lab has already etched your ACC, then you don't have to do this next step. But if the lab has not, then you need to etch it. In the Variolink II kit is a small bag with a syringe or red etchant and a small bottle of silane coupling agent. 
9. Fill the crown with red etchant and let it sit for 40-60 seconds. Wash out over the sink with water from your air-water tip. 
10. Break the bottle of Silane coupling agent, dip a microbrush in it, and paint the inside of the crown with a generous amount. Air-dry for a few seconds. You are now done with the crown preparation.
11. Take the teflon tape, cut it into two pieces if necessary, and then wrap it around the tooth on either side of the prepped tooth. This is to keep the cement from bonding to the adjacent teeth and causing a real problem!
12. Take out your Z100 kit. Etch the tooth like normal. Then apply the 2-in-1 PrimeBond. Air dry a good bit and then light cure for 20 seconds on the buccal and 20 seconds on the lingual.
13. Take the Variolink II base AND catalyst of whatever color you chose with the try-in paste. There may be a choice of low viscosity or high viscosity. Vivadent recommends low viscosity for crowns and high viscosity for veneers. 
14.  Mix the base and catalyst in a 1:1 ratio and fill the crown with the cement. The working time is about 3 minutes, so move kind of quickly. 
15. Seat the crown all the way but only apply light pressure at first. Take a clean microbrush and clean the excess cement away from the margins (while still holding the crown down with finger pressure).  
16. Apply a full pressure now and remove any other excess cement that you see with a microbrush.
17. Light cure for 10 seconds each on the buccal and lingual. 
18. If there is no other cement that you see and the fit is still good, light cure for 40 seconds on the buccal and 40 seconds on the lingual. 
19. Remove the teflon tape. Take either a scaler or a #12 blade (#12 blade is better) and go around the margins to remove the remaining cement. You want the margins as clean as possible!
20. Now you can remove the Optragate and check the occlusion.  For a #8 ACC, you want it to match #9 in excursive movements. If #9 doesn't hit in protrusive movements, then your #8 crown should either.  

What if my crown is too short or needs porcelain added to it? 

•     The incisal edge of my #8 crown was 0.5mm shorter than #9. This happens sometime. It looked okay on the cast but was different in the mouth. If this happens to you, consult with your faculty. I was able to take it up to James, and he added some porcelain to it.
• You will need to write a new lab prescription though in order to give him permission to alter what another lab has done. Get the prescription signed and then take him the casts and prescription sheet. 
• It will probably take James about 20-30 minutes. You will probably need to use your porcelain polishing kit to refine the crown afterwards. 

Hope this was helpful!
- Joe