Cast NP onto Ti Abut?

[Marcusthegladiator CDT]

So If I take a stock Ti abut (BioHorizon 4.3 Conical, not that it makes a difference) and create some retention then cast some NP alloy over it to eventually build a screw retained pfm, is that ok?

That's essentially what a UCLA is anyway right? So it shouldn't even be a question? Right?

 

[rkm rdt]

Cast the coping separately ,finish the crown and then cement it to the abutment as you would a hybrid.

 

[tincho73]

Hi
First of all , sorry for my english
Titanium is a very particular element. At 800º C it changes the cristaline structure from alfa to Beta , and becomes very reactive in the presence of oxigen. So that´s why it must be casted in an argon atmosphere.( when you use some cutting disc in a stock ti abuttment you will see some sparks. That is titanium reacting because it goes over 800ºC)
Then , if you put a ring in the burnout oven and the abuttmnet included in it, ant 800ºC it may explode.( just guessing, never tried). suppose that nothing happend, the you must cast the np , and for that you nneed an induction casting machine vacuum and argon capable.
If you get all that done, then you must build the pfm , and you must take in count that np and titanium have different CET , so you must use a porcelain that matches both ( I only know porcelain exclusive to np and special procelain fot titanium [Noritake ti-22] and they can´t be mixed.
I´ve been casting titanium in the late 90 and early 2000 in a manfredi induction casting machine.

Regards

Martin

 

[aqdental]

So If I take a stock Ti abut (BioHorizon 4.3 Conical, not that it makes a difference) and create some retention then cast some NP alloy over it to eventually build a screw retained pfm, is that ok?

That's essentially what a UCLA is anyway right? So it shouldn't even be a question? Right?

So If I take a stock Ti abut (BioHorizon 4.3 Conical, not that it makes a difference) and create some retention then cast some NP alloy over it to eventually build a screw retained pfm, is that ok?

That's essentially what a UCLA is anyway right? So it shouldn't even be a question? Right?

Hi Marcus, a successful overcast needs the casting alloy to infuse the surface of the alloy you cast on.
Only a mechanical bond will not be enough. This is why UCLA are made with non oxidising alloys. Also burn-out temp. must be quite high (850/900) . This temperature will destroy the Titanium which cannot be heated at more than 830 ( I think, not 100 % sure). Titanium will became brittle.also it will generate too much oxide.
You also have very different CTE which means a lot of tension during cooling phase after ceramic firing.
I know there is a company which produce cast-on NP abutments ( made of Tlite) . Never used them so can't tell if they work or not. Go hybrid, easy and trouble free. My 2 cent.

 

[Stebar1959]

A couple of years ago I cast np metal on to an astra titanium temp abutment to make a long term composite provisional which was meant to be replaced in about six months. It actually failed in the mouth 16 months later lol. It actually snapped near the gingival of the crown, sheared straight across. Looking at the exposed metal it did not look very good. I presume it was some sort of metal fatigue due to overheating the ti abutment during the casting procedure as mentioned by aqdental.

 

[rkm rdt]

Cast the coping separately ,finish the crown and then cement it to the abutment as you would a hybrid.

 

[primus]

Hi
First of all , sorry for my english
Titanium is a very particular element. At 800º C it changes the cristaline structure from alfa to Beta , and becomes very reactive in the presence of oxigen. So that´s why it must be casted in an argon atmosphere.( when you use some cutting disc in a stock ti abuttment you will see some sparks. That is titanium reacting because it goes over 800ºC)
Then , if you put a ring in the burnout oven and the abuttmnet included in it, ant 800ºC it may explode.( just guessing, never tried). suppose that nothing happend, the you must cast the np , and for that you nneed an induction casting machine vacuum and argon capable.
If you get all that done, then you must build the pfm , and you must take in count that np and titanium have different CET , so you must use a porcelain that matches both ( I only know porcelain exclusive to np and special procelain fot titanium [Noritake ti-22] and they can´t be mixed.
I´ve been casting titanium in the late 90 and early 2000 in a manfredi induction casting machine.

Regards

Martin

Titanium and Zirconia produce sparks because of the poor thermal conductivity.

The heat generated from mechanical grinding does not dissapate into the surrounding material.

The heat stays right at the cutting area and temps exceed 3000F++ at that area.

White colored sparks are waaaaaaay over 800C my friend. LOL Double that temp!

Boiling temp of Ti is 5949F !! (3287C)

The Ignition temp in presence of O2 is around 2900F minimum.

No C&B burnout furnace comes close to those temps.

You do not need special equipment or Argon to cast NP to Ti. That alloy does not reach 3000F in molten state, I don't think?

Never heard of a lab go BOOM because of Ti, but I will try today!

 

[adamb4321]

So If I take a stock Ti abut (BioHorizon 4.3 Conical, not that it makes a difference) and create some retention then cast some NP alloy over it to eventually build a screw retained pfm, is that ok?

That's essentially what a UCLA is anyway right? So it shouldn't even be a question? Right?

Like the others say, UCLA's aren't Ti but some sort of non oxidising gold alloy, you cant cast over Ti. Biohorizon make proper UCLA's in engaging and non engaging varieties so looks like you'll need to order some of those.

 

[Marcusthegladiator CDT]

Nice info guys...
Well we'll have to do it differently.
Long story short a doc inquired about an implant for a patient he hadn't see. Only talked to the surgeon about it.
So he knew he was going to be working with a Nobel Biocare conical 4.3.
He asked me what abutments he should get. I knew he didn't want to spend the extra dough on their stock esthetic abutments. So I told him to order their snappy variety. One 3mm and one 1.5 mm both in the wide variety.
He only ordered the 3mm.
And the tissue is almost perfectly 1.5mm. So as well, the 15mm wouldn't have worked either. But I told him, he could have forgot about the lab building onto the replica. Just simply seat the abutment, run over the shoulder prep to make things sub g, and decrease any occ clearance necessary. Then take a normal impression as if it were a natural abut.
But he only had the 3mm abut so its not possible.
So he gave me a snappy impression, and the abutment itself... So I wont be pouring the implant replica, but seated the abutment into the snappy and ordered the implant replica.
But from the bite reg, I can see that once the implant replica arrives and I pour/mount, I will have about 4mm IF THAT from the crest of the gingiva to the opposing. However the opposing is a natural tooth and its a large lingual cusp of that tooth that is in the way and can likely give me much more room.
So until I get this poured, I dunno what were gonna make.....
But this doc says, just do whatever.
Any ideas...

 

[rkm rdt]

wtf do think the picture is?

 

[Marcusthegladiator CDT]

wtf do think the picture is?

Its not a chocolate covered bannana?
I know, But I cant use the abutment I have, its not even adjustable, its the 3mm, and even if I tried to adjust and bring the collar down, its too tapered to do so.
I think we may just waxup, and send to have an anotomical zirconia, and then build the screw retained. I would prefer a hybrid, and could do it in house, but Im unsure if the meso blocks for the MXCL come in a translucent zirc...
Just exploring options, if I could use the abutment I have at the moment, I would just build the chocolate covered bannana you showed me.

 

[tincho73]

Titanium and Zirconia produce sparks because of the poor thermal conductivity.

The heat generated from mechanical grinding does not dissapate into the surrounding material.

The heat stays right at the cutting area and temps exceed 3000F++ at that area.

White colored sparks are waaaaaaay over 800C my friend. LOL Double that temp!

Boiling temp of Ti is 5949F !! (3287C)

The Ignition temp in presence of O2 is around 2900F minimum.

No C&B burnout furnace comes close to those temps.

You do not need special equipment or Argon to cast NP to Ti. That alloy does not reach 3000F in molten state, I don't think?

Never heard of a lab go BOOM because of Ti, but I will try today!

ok ... lets think of it...

1- "The heat generated from mechanical grinding does not dissapate into the surrounding material."

Try to grind an stock ti abuttment holding it whit your fingers....do you fell the heat? I do , so that`s why i punt an analog in the end of a insulated stick to hold ti abuttmens and grind them.

2- "The heat stays right at the cutting area and temps exceed 3000F++ at that area."

That is above 800ºC. so , Ti at room temp , has an hex cristaline structure ( http://www.ingenieriademateriales.com/wp-content/uploads/2012/03/estructura-cristalina.png )
called Fase alpha.whch maintains and is stable until 882 ºC . Beyond that temp , goes to Fase Beta ,and between Alpha and Beta, Ti becomes ¿¿¿oxygenoustropic?? ( oxigenotropico in spanish).
So, in that area fase changing is happening , and the debriss heated beyond 882ºc is visible like sparks and even you can hear them in little little explosions .

3- "Boiling temp of Ti is 5949F !! (3287C)"

why do you want to boil Ti? i only want to fuse it, and that temp is 1670ºC (3038ºF)

4- "The Ignition temp in presence of O2 is around 2900F minimum."

Wrong . Ti reacts in presence of O2 at 882ºC (1619 ºF) when changes form alpha to Beta

5-"No C&B burnout furnace comes close to those temps."

burnout is made in a clasical way, to eliminate wax , at 900ºC (1652ºF) ,( lets say we leave it at 800º to avoid ti fase changingand reaction on O2) then it goes down to 300ºC (572ºf) and then goes to the induction casting machine , and it is fused at 1670º , not boiled ( or do you boil your metals and alloys insted to take them to liquidus/solidus stage?

6- You do not need special equipment or Argon to cast NP to Ti. That alloy does not reach 3000F in molten state, I don't think?

in first place, you can`t cast NP to Ti. In second place , if there is a chance to do that, you will need Argon to avoid Ti contamination with O2. ok? Np casting is around 1200ºC and that is way beyond fase changing for ti , so if Np reachs Ti at a normal atmosphere, Ti will react with O2 .

7-"Never heard of a lab go BOOM because of Ti, but I will try today!"


Me neither, but what i´ve seen is Ti making a small explosion in the crucible in the interior of the iduction casting machine chamber because the vacuum was defective and argon was leaking and O2 entering....

hope this helps

 

[primus]

It sparks because of poor thermal conductivity. Same with Zirconia. Very similar properties.

Of course it does conduct some heat into surrounding areas, but nowhere as much or as fast as any other alloy we use because of the major difference in thermal conductivity.

Below is why Zr and Ti spark and why Gold and Silver do not when you grind on them. 10x-20x less thermal conductivity!! OK with you?? It is a MAJOR difference!



Gold Thermal conductivity318 W·m−1·K−1
Silver Thermal conductivity429 W·m−1·K−
Zirconium Thermal conductivity22.6 W·m−1·K−1
Titanium Thermal conductivity21.9 W·m−1·K−1

 

[Marcusthegladiator CDT]

You guys get sparks when you grind zirconia cause your grinding to hard and fast.
Just kidding, i know i know.

 

[tincho73]

It sparks because of poor thermal conductivity. Same with Zirconia. Very similar properties.

Of course it does conduct some heat into surrounding areas, but nowhere as much or as fast as any other alloy we use because of the major difference in thermal conductivity.

Below is why Zr and Ti spark and why Gold and Silver do not when you grind on them. 10x-20x less thermal conductivity!! OK with you?? It is a MAJOR difference!



Gold Thermal conductivity318 W·m−1·K−1
Silver Thermal conductivity429 W·m−1·K−
Zirconium Thermal conductivity22.6 W·m−1·K−1
Titanium Thermal conductivity21.9 W·m−1·K−1

Well , no argue on that , but: grind => Heat in that spot => temp goes up => Ti is half way cherry red => sparks fly ( i presume ti in form of debriss heated up , that is why i see it like spark )=> cherry red is near 882ºC so I hear the spark very little tiny explosion => spark dissapear .... was that Ti in the form of a little debriss fliyng away form the grind spot and reacting in presence of O2?

It does not make noise when grinding ZR...

And last but not least : "OK with you??" should I put an aggresive tone on that? because we are sharing our knowledge......

 

[Marcusthegladiator CDT]

How is the restoration screw retained? The abutment is held in place by the screw and the restoration by cement.

 

[Labwa]

Its cemented together after layering, The layered crown has the access hole. it would look like a UCLA but over titanium. Titanium is not good at 750c plus. Then think of the alloy melting at 1200-1400 C flowing onto it. Not to mention cte issues. RKM's option is your best choice i think.

 

[Marcusthegladiator CDT]

Its cemented together after layering, The layered crown has the access hole. it would look like a UCLA but over titanium. Titanium is not good at 750c plus. Then think of the alloy melting at 1200-1400 C flowing onto it. Not to mention cte issues. RKM's option is your best choice i think.

Why not just cement it in the mouth like usual, and not have a coping with a hole.

 

[CatamountRob]

Why not just cement it in the mouth like usual, and not have a coping with a hole.

Retrievability and no cement left behind.

 

[CatamountRob]

So sorry.