Burs for Zirconia

[Lindsay Patterson]

What burs are recommended for grinding on Zirconia? Specifically, cutting in anatomy, bulk grinding, and polishing.

 

[user name]

The ones in the mill. Do better designs.

 

[Lindsay Patterson]

Not quite what I had in mind. You are a bundle of joy though How about not responding next time.

 

[user name]

How about learning to do proper designs. Theres no need to grind on Zr after its out of the mill; in fact it contraindicated. Thats how micro cracks start and cause failure.

The reason no one else responded to your question is because its stupid. You dont grind on Zirconia.

 

[user name]

@Lindsay Patterson

Please forgive me for my rudeness. Ive been a jerk lately, not just to you. My apologies.

Are you having to adjust crowns designed by a different tech?

 

[Car 54]

What burs are recommended for grinding on Zirconia? Specifically, cutting in anatomy, bulk grinding, and polishing.

If I don't like my anatomy or need to add other surface textures etc after I've designed and milled, then I'll tweak it in the green state. For any occlusal anatomy touch up in the green state, I use inverted cone diamonds (HP). Like user name mentioned, I try to avoid any burs/diamonds when it's sintered for the occlusion, unless it's slow speed with water.

If I need to take away some buccal lingual etc fullness in the green state I use Pacific Abrasives flat and knife edge course wheels, larger tapered diamonds etc. Wagner Rotary Instruments also make some nice products for green state zirconia adjusting and smoothing.

Anything after it has been sintered, I use Wagner's Berry series for contacts, margins etc. The Blue knife edge/square and green course are now my favorites.

 

[Lindsay Patterson]

Thank you so much for the very informative response Car 54

 

[PRO ARTS DL]

Check with Wagner Rotary. They have a zirconia finishing kit.

 

[Contraluz]

cutting in anatomy, bulk grinding,

Unfortunately, that is asking for trouble, in sintered Zr. What I would recommend you is to do a regeneration cycle, after heavy grinding on your zirconias...

 

[Lindsay Patterson]

Contraluz,

Would you mind recommending what regeneration cycle you use? I have been a designer for 7+ years but after i designed them, they went to another department and I never go the opportunity to learn how to finish them. Now I am at a new lab and Im running the whole show and this part is a big learning curve for me. I appreciate the help and suggestions....thank you

 

[Lindsay Patterson]

contraluz....would you mind giving me the firing cycle that you use for regeneration? I have been looking now for a while and all I can find are articles talking about what the regeneration cycle is and does but nothing with exact firing. 1050 C - 1922 F as the high temperature was all I can find. I would really appreciate your help....thank you

 

[sirmorty]

Yeah you should be touching your green state zirconia, If you just accept what the mill is making I don't know what to say about that.

Everyone touches it in green state and if they don't they are the best designer in the world and and have a mill that can just make perfect surface structure with it's .6mm tool..

The Wagner Green State kit is good and has a lot of tools, But you will find yourself only using a couple favorites.

Grinding sintered zirconia is a pain. I try to avoid it but sometimes it happens. That's why they sell the tools to adjust them. Wagner has a bunch of options.

Not sure about regeneration firing. If it has a micro fracture it's not like it will seal itself by going to a temp. It will always be there.

But studies have shown that it does help
https://www.ncbi.nlm.nih.gov/m/pubmed/28024816/

Looks like they are going to 1000 for 30 minutes.

 

[Car 54]

In Chicago about 4-5 years ago, Dr McLaren (used to, still does lecture for Vita?) mentioned this cycle for regeneration:
Base temp to 1040c at a temp rate of 70c a minute no vacuum. Hold for 10 minutes with a 4 mn decent.

Here is what Vita shows in one of thier manuals, see pg 17: https://www.dt-shop.com/fileadmin/media/ga/05899_ga_enu.pdf
They are both pretty close to each other.

 

[Lindsay Patterson]

All I meant by grinding on the sintered zirconia was making adjustments on contacts and making anatomy nicer in certain areas that I missed in my design. Other than removing anything left over from the sprues, I dont touch the green state crown. I purchased 2 different kits from 2 different companies and was not satisfied with either. This part of the process is foreign to me because I never finished my crowns before now. As a brand new laboratory trying to get doctors and work, I need to send out beautiful restorations and until i get more experience with the whole process then grinding is a necessity. When you know better you do better. Thank you all for your help, this is the most useful tool for information and Im glad I joined the network

 

[sidesh0wb0b]

What burs are recommended for grinding on Zirconia? Specifically, cutting in anatomy, bulk grinding, and polishing.

as much as @user name had an odd approach, he is correct. you shouldnt be grinding that much on sintered zirconia. if you are, you should address it in the pre-sinter state. and thats where the real question is, why? if youre doing that much grinding on sintered zirconia, you are causing microfractures that could lead to significant fractures down the road.
with that said, we all have to spot something here and there....low speeds, and under water are key. @sirmorty and @PRO ARTS DL are spot on with the wagner setup. me, well i just use a small stone, slowly, under water. smooth with a silicone wheel. and this is of course when i have to touch these things. i really try to avoid it if at all possible. all my grinding is usually spotting contacts until fully seated on a solid cast. 1-3min per crown TOPS for finishing. i do all my work in the design phase and minimize everything afterward. less headaches with remakes and adjustments this way....working smarter not harder. its like when you paint a room in your house....take your time, do the trim painting first. if done right, the rest is a breeze. time consuming up front (sort of, computers make it easier lol) but makes the rest of the process super easy.

 

[sidesh0wb0b]

All I meant by grinding on the sintered zirconia was making adjustments on contacts and making anatomy nicer in certain areas that I missed in my design. Other than removing anything left over from the sprues, I dont touch the green state crown. I purchased 2 different kits from 2 different companies and was not satisfied with either. This part of the process is foreign to me because I never finished my crowns before now. As a brand new laboratory trying to get doctors and work, I need to send out beautiful restorations and until i get more experience with the whole process then grinding is a necessity. When you know better you do better. Thank you all for your help, this is the most useful tool for information and Im glad I joined the network

we are happy to have you here! even when we are grumpy LOL
i cut milling supports with a small flame diamond and smooth with amann girrbach zirconia smoothing cones. simple and fast and leaves a smoother surface so i dont have to touch it post-sinter.

 

[Lindsay Patterson]

Thank you side show Bob for your response. To clear up my original post.... bulk grinding was for adjusting a bridge that was not done at my lab. Patient was very unhappy and did not want to take another impression so I did the best I could. In the end, the patient was more than satisfied with her new bridge. I had pre-warned the dentist about grinding and I took extra precaution to try and avoid any micro cracks and things of that nature by using water. However, it took way too much time to do, so I thought maybe I cheaped out on my kit. I will add more information to my next question so everyone knows exactly why I am asking...I realize now that would have helped you guys respond.

thanks a million

Lindsay

 

[PRO ARTS DL]

I didn't realize this was for adjusting once sintered. The kit from Wagner is for green state, not really sure if they have for post sintered zirconia.

I do have to agree with others here. At most you should only be adjusting contacts and sometimes occlussion after sintering. Not really any bulk grinding or detailing. Most of your anatomy should be done at the design step, some extra detailing on the green state if needed and very little adjustments after sintering.

For adjusting after sintering you can just use green diamond stones.

 

[Lindsay Patterson]

I thought I explained why I was asking about post sintering grinding in my last post. I appreciate the concern of why I would possibly touch the sintered crown....but other than this network I havent met any technician that doesnt touch their crown after its sintered. I am not re contouring every crown but as I am getting this lab started I must send esthetic and functional crowns (maybe being over critical and questioning more than I should). The lab I came from I designed about 40+ crowns a day and ran 4 milling machines by myself for 6 years and I can count on one hand the amount of crowns that came back to redesign. I am extremely new to this part of the process but not new to dental lab technology and been a part of the digital world since 2004.

Thank you to those who gave good and helpful suggestions....greatly appreciated

 

[Contraluz]

contraluz....would you mind giving me the firing cycle that you use for regeneration? I have been looking now for a while and all I can find are articles talking about what the regeneration cycle is and does but nothing with exact firing. 1050 C - 1922 F as the high temperature was all I can find. I would really appreciate your help....thank you

I am sorry, I only saw you referring to my post, right now. If you have a newer Programat, it is preprogrammed as P151 and/or P152. There is even a program in the sintering furnace (S1 1600).

Regardless, I attached a pdf with the necessary info...

(Edit for better understanding)