How do You test accurate fit of crowns ?

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Powder spray comes off really easily and I never spray the die, just the inside of the crown very very lightly.
 
Marcusthegladiator CDT

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sorry senior, vacalon quick check comes off clean as a whistle. And I really don't know where it's going to be holding up each case.
It doesn't even steam off, I barely use the stuff, but other people at the lab that do always have red stained dies and casts... So is there a secret?
 
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I hate the coloured scan sprays, having green crud under my finger nails isn't a good look. If I do have a case that needs a little "squirt" I use a white spray. No heavy colours to stain the model or fingers, job done.
 
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You can always look for the crumble of die stone where your margin just chipped off from a high point or uneven margin after seating the crown.Dontknow Really I dont see why its such a big deal to spritz a crown and see how it touches the die.. seems lazy maybe? I bet you would be surprised at what you see.

Are these "high points" inevitable when scanning stone dies?
Do scanner camera specs provide better fit because there is more data being captured on the very sharp edge margins
 
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Inevitability is the cornerstone of dental technology. In a perfect world, every square peg fits in a square hole, but Ive never been in a dental lab(or seen technology) that was 'perfect' .. This is why I double check what my robot makes with powder spray. I will leave accuracy of scanners to someone that cares about that.
 
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I use lipstick with brush it save cost and effective
 
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Wow, can't believe I missed this thread...
Tanaka Bite X isca water soluable paste that spreads out down to 5 microns. Used it since 1984 and wouldn't open my lab door if it wasn't there. Unless...you have perfectly designed margins...smooth everywhere in All dimensions, your mill can only take it so far. In, out, up and down mini gyrations...somewhat conventional preps, in my opinion, will need some after mill adjustments for pre-mature marginal contacts. A touch of spot grinding does the trick. Key to note is if you have a normal die space dialed in and never ever get an occlusal marking once seated or better yet leave a small area on the occusal with no cement relief, this should also mark if your crown is fully seated and not hung up by marginal premature contacts. I have always fitted crowns until I get markings 360 around margins. Actual true seal, if not and premature marginal contacts exist, marginal openings could be well in excess of 200 microns or more. Its not ever a case of the margins being short, unless margins are really marked improperly, but rather things the mill couldn't get to All areas properly. I would love it if someone could explian a better path, been milling and fitting for over 10 years now and far less adjustments are required nowadays but there is certainly still a need to.

I've often heard ...just remargin because of some small openings. Truth is crown is just hung up on premature marginal contacts and if left so, occlusal and proximal contacts are also thrown out of wack.

Bite-X does and always has been excellent for internal and occlusal markings. Water soluable and available in red, yellow and green. Seal your die, model and steams off completely.

Hope this helps someone...

Sent from my LG-H873 using Tapatalk
 
rkm rdt

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Wow, can't believe I missed this thread...
Tanaka Bite X isca water soluable paste that spreads out down to 5 microns. Used it since 1984 and wouldn't open my lab door if it wasn't there. Unless...you have perfectly designed margins...smooth everywhere in All dimensions, your mill can only take it so far. In, out, up and down mini gyrations...somewhat conventional preps, in my opinion, will need some after mill adjustments for pre-mature marginal contacts. A touch of spot grinding does the trick. Key to note is if you have a normal die space dialed in and never ever get an occlusal marking once seated or better yet leave a small area on the occusal with no cement relief, this should also mark if your crown is fully seated and not hung up by marginal premature contacts. I have always fitted crowns until I get markings 360 around margins. Actual true seal, if not and premature marginal contacts exist, marginal openings could be well in excess of 200 microns or more. Its not ever a case of the margins being short, unless margins are really marked improperly, but rather things the mill couldn't get to All areas properly. I would love it if someone could explian a better path, been milling and fitting for over 10 years now and far less adjustments are required nowadays but there is certainly still a need to.

I've often heard ...just remargin because of some small openings. Truth is crown is just hung up on premature marginal contacts and if left so, occlusal and proximal contacts are also thrown out of wack.

Bite-X does and always has been excellent for internal and occlusal markings. Water soluable and available in red, yellow and green. Seal your die, model and steams off completely.

Hope this helps someone...

Sent from my LG-H873 using Tapatalk
So how do you deal with IOS cases?
 
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They just dont fit as well RKM.
Nice post sda, hard to believe some people dont fit check their crowns...
 
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This new hire (Finisher) is still expecting perfect sitting crowns
Someone shoot me
 
rkm rdt

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They just dont fit as well RKM.
Nice post sda, hard to believe some people dont fit check their crowns...
I guess my drs have been lying to me then.
 
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You still have to assume that the pvs is 100% accurate don't you?
We see quite a few triple tray impressions. I don't put much faith in a plastic tray.
 
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I didnt say IOS crowns dont fit, just not as well. I dont assume anything is accurate, its why I fit the crown. How can you, or a Dr for that matter, assume a crown doesnt have any premature intaglio contact? Because the margins appear seated, or an xray shows the M/D walls? You cant see inside a crown unless you fit check it. How do you, or the Dr know the margins, or tooth prep, isnt micro chipping these premature areas off when smashed down during seating. There is a better way, some just choose not to do it.
 
rkm rdt

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I didnt say IOS crowns dont fit, just not as well. I dont assume anything is accurate, its why I fit the crown. How can you, or a Dr for that matter, assume a crown doesnt have any premature intaglio contact? Because the margins appear seated, or an xray shows the M/D walls? You cant see inside a crown unless you fit check it. How do you, or the Dr know the margins, or tooth prep, isnt micro chipping these premature areas off when smashed down during seating. There is a better way, some just choose not to do it.
I'm saying you can't do that with a printed die.It would have to be done in the mouth to have any relevance wouldn't it?
 
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Possibly. Im not denying a crown will fit right off the mill.. I could send out my crowns right off the mill and feel the margins are 99% there (or there 99% of the time).. they are closed on the die under 10x, and for some people thats good enough.. its certainly faster. The Drs I used to work with in europe had intraoral microscopes.. they expect 100%, not 99%. I would say a good PVS impression, poured up well, is as accurate of a replication of a tooth, in the real analog world, that you can get.. but I get it, most Drs dont care about closed margins, 'because cement' , so why should we right?
 
rkm rdt

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Possibly. Im not denying a crown will fit right off the mill.. I could send out my crowns right off the mill and feel the margins are 99% there (or there 99% of the time).. they are closed on the die under 10x, and for some people thats good enough.. its certainly faster. The Drs I used to work with in europe had intraoral microscopes.. they expect 100%, not 99%. I would say a good PVS impression, poured up well, is as accurate of a replication of a tooth, in the real analog world, that you can get.. but I get it, most Drs dont care about closed margins, 'because cement' , so why should we right?
I have not seen improvement in many pvs impressions lately. Then again , maybe we shouldn't blame the material right ?
 
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