White spots

D

dentek1

Member
Full Member
Messages
11
Reaction score
3
I have been getting white spots on my zirc crowns after sintering. I tried using new beads, but that didn't help. Anyone else having this problem?
 
sidesh0wb0b

sidesh0wb0b

Well-Known Member
Donator
Full Member
Messages
5,649
Reaction score
649
I have been getting white spots on my zirc crowns after sintering. I tried using new beads, but that didn't help. Anyone else having this problem?
pics
 
JohnWilson

JohnWilson

Well-Known Member
Full Member
Messages
5,487
Reaction score
1,575
Check to make sure you compressor is only sending clean dry non oily air. Also check to make sure you are not eating fried chicken when you cut them out of the disk :)

I have heard that tiny drops of oil from the compressor can seal the air and not allow the colorant to penetrate.
 
Sevan P

Sevan P

Well-Known Member
Full Member
Messages
3,413
Reaction score
641
Do you let the units dry before placing them on the beads? 1mm or .5mm beads?

Sent from my SM-G920V using Tapatalk
 
Affinity

Affinity

Well-Known Member
Donator
Full Member
Messages
6,917
Reaction score
1,062
Make sure they are dry before you color. I use gloves to color.. We were always taught about the oils in our fingers contaminating metal, so why would they not affect a porous material like green zirconia? and not allow the color to penetrate on the surface. Probably not what is causing your spots.. Did you try using a new tray also, or just new beads? My amann oven says not to mix different zr in each trays, one for zolid and one for zi. Says that white spots can occur.
 
Zsolt Kovacs

Zsolt Kovacs

Member
Full Member
Messages
19
Reaction score
13
Some Zr. powder what stay on the surface after milling also can produce some white spot. Clean well the surface with a soft brush and air before sintering.
 
Brent Harvey

Brent Harvey

Well-Known Member
Full Member
Messages
411
Reaction score
188
Are you using Preshaded or white zirconia? a couple of things can be happening, bad beads if thats not the problem it could also be the type of beads, i have seen low purity (cheap) beads cause this problem as well but only to pre-shaded zirconia. Also it try to swap out you tray and see if that helps.
 
2000markpeters

2000markpeters

Active Member
Full Member
Messages
472
Reaction score
79
I use a wet/dry mill. I found in the past if a drop of milling oil droped on the disc, then in that area the colourant could not penetrate. I have had the same happen to multilayer zirc. Oil is a real problem with zirc as far as I can see. We ahve taken steps to insure that this doea not happen any more.
 
D

dentek1

Member
Full Member
Messages
11
Reaction score
3
I am now drying in a convection toaster oven instead of under a heat lamp, and I also got new beads. Seams the problem has been solved. Thanks for everyones input and help!
 
Rainbow Machine

Rainbow Machine

Member
Full Member
Messages
42
Reaction score
5
Could also be defects in the puck manufacturer. I've had spots appear as well but only in certain pucks. When I would run a diff zirc in the same oven, using the same beads, no spots would appear. When I would return to the zirc in question, sinter in clean, more expensive beads, I would get the spots again. Sometimes white, sometimes brown. I always used gloves when cutting, finishing, staining in the green state and would never used compressed air. Still had spots. The puck manufacturer kept denying the issue, implying user error. I heard later on through other grapevines that the puck manufacturer in question was getting their pucks made cheaply in China.
 
Sda36

Sda36

Well-Known Member
Full Member
Messages
1,094
Reaction score
93
And??? [emoji6]

Sent from my LG-H812 using Tapatalk
 
PDC

PDC

Well-Known Member
Full Member
Messages
997
Reaction score
232
Are you using Preshaded or white zirconia? a couple of things can be happening, bad beads if thats not the problem it could also be the type of beads, i have seen low purity (cheap) beads cause this problem as well but only to pre-shaded zirconia. Also it try to swap out you tray and see if that helps.

I am seeing this in the Katana UTML from Straumann. At first I thought something was up with my glaze, but I blasted it off and could still see them. Microscopic, but they are there. I'm beginning to think this is something inherent in the Pre-shaded translucent products. I do remember seeing this with some of the anterior zirc from Argen as well.

Maybe it has more to do with the way the colors are being added to the powders before sintering as opposed to dipping. Dontknow
 
Brent Harvey

Brent Harvey

Well-Known Member
Full Member
Messages
411
Reaction score
188
I am seeing this in the Katana UTML from Straumann. At first I thought something was up with my glaze, but I blasted it off and could still see them. Microscopic, but they are there. I'm beginning to think this is something inherent in the Pre-shaded translucent products. I do remember seeing this with some of the anterior zirc from Argen as well.

Maybe it has more to do with the way the colors are being added to the powders before sintering as opposed to dipping. Dontknow
Yes you are correct. It is a possibility that is the Pre-shaded Powder and just processed to quickly, leaving the Iron Oxides not fully mixed which evaporates in the final sintering process on your end leaving void spots in the zirconia making it look like white spots.
 
BobCDT

BobCDT

Well-Known Member
Full Member
Messages
2,870
Reaction score
521
I am seeing this in the Katana UTML from Straumann. At first I thought something was up with my glaze, but I blasted it off and could still see them. Microscopic, but they are there. I'm beginning to think this is something inherent in the Pre-shaded translucent products. I do remember seeing this with some of the anterior zirc from Argen as well.

Maybe it has more to do with the way the colors are being added to the powders before sintering as opposed to dipping. Dontknow
My lab has used so many of UTML discs, no white spots. Is Straumann milling and sintering or are you buying disc form straumann. This is most likely happening in the milling, post processing or sintering.
 
PDC

PDC

Well-Known Member
Full Member
Messages
997
Reaction score
232
My lab has used so many of UTML discs, no white spots. Is Straumann milling and sintering or are you buying disc form straumann. This is most likely happening in the milling, post processing or sintering.

They do the milling and sintering. All I do is glaze it. If you have some ideas with regards to solving this issue, I would be happy to pass them along. I like the look of this material (minus the white spots),but I am thinking the density and strength of the crown may be affected by whatever is causing this.
 
Brent Harvey

Brent Harvey

Well-Known Member
Full Member
Messages
411
Reaction score
188
Pictures would help us greatly. A good visual is great to have.
 
PDC

PDC

Well-Known Member
Full Member
Messages
997
Reaction score
232
Pictures would help us greatly. A good visual is great to have.

I will attempt to take a few macro shots tomorrow. Hopefully I can focus camera well enough to pick up the problem.
 
BobCDT

BobCDT

Well-Known Member
Full Member
Messages
2,870
Reaction score
521
Straumann has a large R&D department. I would return the work and have them solve the problem.
 
PDC

PDC

Well-Known Member
Full Member
Messages
997
Reaction score
232
Straumann has a large R&D department. I would return the work and have them solve the problem.

That's my plan, but it takes forever if it even happens at all, getting things fixed with large companies like this. Things always get referred to the "next tier"...which is a secret holy place obviously closed to us of the lower caste.
 

Similar threads

B
Replies
4
Views
746
Bowman1989
B
dentallabmne
Replies
18
Views
783
Andrew Priddy
Andrew Priddy
G
Replies
4
Views
672
FASTFNGR
F
Top Bottom