John Post on thu 17 apr 08
I once had a tooth get a crack in it. My favorite part of the process
was when the dentist brought out his "test tiles" (color chips) so
that he could match the crown he was making to my tooth color.
John Post
Sterling Heights, Michigan
http://www.johnpost.us :: cone 6 glaze website ::
http://www.wemakeart.org :: elementary art website ::
On Apr 16, 2008, at 5:00 PM, John Hesselberth wrote:
> On Apr 15, 2008, at 7:22 PM, Nobody Special wrote:
>
>> Not that it makes a lick of difference, but dental crowns ARE
>> porcelain,
>> laid up over a base of noble metal.
>
> Hi James,
>
> I would have to say yes and no. You certainly would not have much
> luck throwing a pot out of it. A typical composition is very low
> clay. Norton in Fine Ceramics, p 468 gives the classic body
> composition as 81% feldspar, 14% quartz, and 5% clay. This gives a
> self glazing high glass body with nearly the same translucency as a
> tooth. So it has the same materials in it as "our" porcelain, but at
> such different ratios it is a very different material. They also
> often flux it to get it to vitrify at lower temperatures. I believe
> my dentist told me current "dental porcelains" are fired at more or
> less earthenware temperatures.
>
> So calling it porcelain is certainly going to be confusing to a
> potter who has a very firm idea of what porcelain is.
>
> Regards,
>
> John
>
>
> John Hesselberth
> http://www.frogpondpottery.com
> http://www.masteringglazes.com
>
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Nobody Special on thu 17 apr 08
On Thu, 17 Apr 2008 02:11:51 -0400, John Post wrote:
>I once had a tooth get a crack in it. My favorite part of the process
>was when the dentist brought out his "test tiles" (color chips) so
>that he could match the crown he was making to my tooth color.
>
John...
My dad had hundreds and hundreds of those things. I used to love messing
with them (and all of the molds and plaster models of peoples' rotten
teeth!), but had to be very careful not to mix them up.
The really odd thing was all of the colors of the dental porcelain. He had
rack after rack of pinks, yellows, greens, blues, and browns. Kind of odd
to think that all of those colors were necessary to match "white" teeth!
For a while they tried to use digital scanners, kind of like the paint chip
scanners at Home Depot, but they just couldn't account for the shading and
variation.
...James
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