noritake group

[martintay]

There`s something seriously wrong

 

[Tayebdental]

What alloy are you using with Noritake porcelain?, it might be either a metal substructure support issue or compatablity of alloy to ceramic. I could be wrong.

Bubbels come from suface contamination of the alloy, or entrapment of bubbles during build ups, or the build up liquid is contaminated, many variables are involved.

Once in a while i experince a crack in a crown on the first bake, but it will heal on the second bake once tension in release.

 

[Principefly]

Have you used some new separating liquid on contact points?
Could it be that it was absorbed by the ceramic and created bubbles during baking

 

[martintay]

Have you used some new separating liquid on contact points?
Could it be that it was absorbed by the ceramic and created bubbles during baking

Agreed but I don`t think that is causing the "Cracks"

 

[adamb4321]

It's a weird one, very occasionally I'll get a bubble that's blown up from the surface of the metal but this isn't like that.

The metal frames were cast in Argenco Argipal, I'll scrap the crucibles on Monday and use completely fresh metal but I'm not convinced its a metal issue.

I don't use any separating liquids on contact areas but I do use baby oil on porcelain margins which hasn't caused any issues before.

I do use a wet tray and sometimes find the porcelain is wetter than I'd like. My junior colleague built units cast in the same batch yesterday also with butt fits and had no issues at all, so it's probably something I'm doing.

 

[martintay]

Umm Butt fits = 2 extra firings maybe ?

 

[adamb4321]

Yeah, the two extra firings probably don't help but it still shouldn't happen.

The crowns my colleague fired were done in a different furnace, albeit the same manufacture and same firing parameters so I'll also try using the other furnace and see if it makes a difference

 

[Marcusthegladiator CDT]

I've had the strangest thing happen with Noritake recently. I get bubbles appear correction firings, particularly on contact areas. When I grind them they don't go down to the opaque or metal work, I thought maybe under firing but the translucency looks good and they aren't porous otherwise. If I try to trim out and add more ceramic I then get tension cracks. Any ideas?

Use add on with glaze liquid for your contacts..

 

[Tayebdental]

It is called "addmate" for Noritake Ex3 porcelain.

 

[Principefly]

Saturday I was at the Colloquim Dental in Brescia Italy.
I attended the conference of the Japanese technician Naoto Yuasa.
Really very skilled, an artist.
He uses the Noritake ceramics, and next year will be released a book on the layering , which will surely be a must-have for every user of ex-3!

 

[Travis]

Groups are back up.

 

[Principefly]

sorry,I don't undertsand the meaning of "back up"

 

[Travis]

http://dentallabnetwork.com/forums/xfa-groups-group/noritake.7/group-detail

 

[adamb4321]

Yeah, the two extra firings probably don't help but it still shouldn't happen.

The crowns my colleague fired were done in a different furnace, albeit the same manufacture and same firing parameters so I'll also try using the other furnace and see if it makes a difference

Just thought i'd update on my problems.

I think I was building in air bubbles during the additions (one of those days when the phone rings off the hook) and the porc was getting too dry.

 

[McTeeth]

EX-3 is where its at for Press-to-metal or what?

 

[Cbite Dental Products]

EX-3
View attachment 5526 View attachment 5527 View attachment 5528 View attachment 5529

Cad/ Cam is a great thing...but layering porcelain like this...layer by layer...increment by increment...creating all the anatomy by hand...is an art...something really special...to those who are out to re-create nature.

 

[jack1]

Is anyone having cracks when using ex3 on a noble alloy?? I am having cracks when using Penceram Noble from Pentron!!!

Sent from my SPH-L710 using Tapatalk

 

[Principefly]

Check the compatibility of the CET

 

[RDA]

Penceram Noble's CTE(14.6) is on the upper edge for Noritake(13.4 - 14.5) http://www.kuraraynoritake.com/products/dental-porcelain-and-laboratory-related-materials/ex-3/

Cervical or Incisal Horizontal Cracks in Pontics.
Cause (1)
The CTE of the metal is too high.
Solution / Answer (1)
If the CTE of the metal is outside the range of 13.4 - 14.5
*10-6 [°C]-1 on the 25 - 500°C scale you must change
metals. (For non-precious the range is reduced to 13.9 -
14.1*10-6 [°C]-1 on the 25-500°C scale).

 

[jack1]

Thanks Principefly and RDA .. I appreciate all the information, due to Pentron, Penceram Noble's CTE is 14.4 at 25-500 c still as RDA said on the upper edge for Noritake, but i have been told that Noritake tested this metal and they say it's compatible, will give it couple of more tries and see!!!