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                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               

Lab Prescription for an All Ceramic Crown

I am doing an All Ceramic Crown on tooth #8. Here is a photo of my prescription form (i had already turned in the original, so I just filled out another form and left off the names and signatures):

Lets walk thru the components:

1. Dental Lab - you don't need to put the address, only the name. My faculty recommended two labs for All Ceramic Crowns:  Gray Dental and Oral Arts. I also heard from another student that you can get Mr. Wehby to do a crown with CAD-CAM and have it back in a matter of days.
1. Dr. Mazer (my faculty for this crown) said she uses Gray for all of her veneers and many All ceramics, so I just went with Gray. It usually takes them about 2 weeks to get it back
2. Prosthetic Slip No. and Technician
1. just leave these blank
3. Shade and Mold
1. our patient had some discoloration on his teeth (white spots here and there). Because it was #8, we took a few photos, and I am going to send Gray an email with the photos included in them. When I find out the email address, I will come back and add it here. 
4. Request Section
1. Framework doesnt apply here because its an All Ceramic Crown
2. Set-up  and Process refer to dentures and RPDs, where the lab would set the teeth and/or process the prosthesis into acrylic
3. Bisque Bake is not used by students at the school anymore from what Ive been told.
5. Enclosed Items
1. Mazer told me to include my articulator. Don't forget that your casts have to be mounted when sending off lab work for a crown. 
2. An articulator is not necessary but I just did what Mazer told me. Gray Lab is on vacation next week which means I am without a Whip Mix articulator for 3 weeks, so just keep that in mind.
3. Mazer said that an incisal guide table was not necessary for this case. #6,7,9, 10, and 11 were all intact and in good condition. This patient also had previous ortho treatment. For this reason, the lab has plenty of information to go off to design the crown to work in all of the excursive movements. Some faculty will tell you to make it anyway, and in that case I wouldnt argue with them. 
6. Special Instructions
1. Mazer suggested an E.max crown. I honestly didnt know so I went with that. Talk to your faculty about what they suggest.

Dont Forget - when you turn in your lab work, you also need to include this prescription form AND that little green card (signed by your coordinator) that says the patient has paid at least half of the cost.

Hope this helped!
- Joe

Pedo Cahaba

This is a very easy rotation, and you will probably get out early for the day! I was done for the day at 11:30. Talking to a few other people, the latest I have heard anyone having to stay was 1pm. It says its an all day rotation and you are excused from both classes, but you will get out early for sure. When I was there, they only scheduled patients for the morning.

Its pretty similar to all of the other Pedo rotations. You will mainly do prophies and exams. You MIGHT see 2 patients, but most likely it will just be 1. There are 4 students (plus an additional 3 residents) that rotate there, and we only had 6 patients, so you do the math.

There may be the occasional operative or surgical procedure. After doing my exam, Dr. Cheon told me to extract the coronal remnants of a primary canine. So you may be asked to do more than just an exam, so be expecting that.

Thats about it. There is no sign-in sheet. The syllabus says the clinic starts at 8:30. But thats not true. They want you to arrive at 8:30. The first patient doesnt actually show up til 9am. So if you are a little late, its not a big deal. The residents and faculty didnt show up til like 8:55.

As always, shoot questions my way.
- Joe

Post and Core

I think a lot of people have doubts about this procedure so hope this post helps! Let me know if I got anything wrong, and I will change it. I was assisting during this procedure. NOTE: compare with Dr. Broome's write-up in the UAB SOD Standard Operating Procedures handbook. He does a good job of walking through the procedure step-by-step.

 What Do I Do First?

• First off, you are going to give anesthesia.  The tooth you are working on has had a root canal, but the gingiva around it will still be sensitive. 
• Put on a rubber dam. We did an anterior tooth, so we used an anterior clamp. When we were done putting on the dam, it looked like this:

•  Now you are ready to remove the cavit or IRM or whatever. Use a slow speed round bur. 

 Preparing the Canal

•  Get your working length! - Do this by pulling up the endo note. Pull up the patient's yellow card on Salud. Go to EDR Summary --> Endo. And then I think you find the procedure and then double click on it. You may want to consult your faculty on this step. You need the WL & the reference point. 
•   Prep the Canal - remember that there needs to be at least 4-5mm of gutta percha left in the canal. Our WL was 18mm, so we first prepped the canal to a length of 12mm. You can use either:
• Gates Glidden burs - whichever one comfortable fits into the canal
• Post sizing drill (AKA endo rotary burs). Start with the smallest (black) and move up if needed.

• We actually didn't use the GG burs. Our resident told us we just needed to use the rotary post-sizing bur. You attach these to your latch slow-speed handpiece. Turn the speed down so that you don't tear up the canal. Also, make sure you are parallel with the tooth and try to only remove GP. Minimize touching the bur to the canal walls because we don't want the prep to get wider.
• Remember to put a silicone stopper on your bur and set it to the desired preparation depth (e.g. 12mm)

• Take a radiograph - once you think you are the right depth, take a radiograph without the bur in it to make sure you have removed all the GP and are at a good length. We were not far enough so we ended up extending the prep to 15mm, retaking another radiograph, and then proceeding to the next step. 

Preparing the Post

• Post Selection - whatever post-sizing bur you ended with will correspond to the post that you should use. Remember this picture: 

•  Put the silicone stop on the post to the length that you prepped the canal. Wipe the post with alcohol and then make sure that it will seat all the way to the bottom of the prepped canal. Broome says to coat your post with adhesive for 20 seconds and then air dry it. Seat it back into the canal until you are ready to begin cementation.
• Here is your post and core set up:

•  Left to right: alcohol pad, etchant, water syringe, microbrush, L-pop adhesive, microbrush, Rely-X, curing light, and gun for the composite core build-up.

• And here is the included instruction sheet:

A few other notes

• Make sure you fill the water syringe with the water that we have connected to our chair. Don't use water from the sink.
• Ask the faculty where they want you to cut the post off at. For our patient, we left it a little longer due to the amount of missing tooth structure.
• You will need some flowable composite as well as the normal Z100. Start with the flowable and then move to Z100. The faculty may just tell you to fill the whole thing with flowable. 
• Don't forget to etch, prime, and bond for the composite like always. 

If you have anything to add or any questions, let me know!
- Joe