so here's the production of a Brooks or Crown start to finish this is the Dennis
polyvinyl siloxane impression so we poured it up in stone there's the stone model right there of
the prep arch and as you can see this is being put into a three shaped scanner we want to get
this into the digital environment as quickly as possible because everything works better for us
in the digital environment it's so much more consistent if the dentist had sent a digital
impression then we would start right from that but we had a conventional impression so there's
no really good impression scanners out on the market so we still have to pour the model in
stone and now we're going to scan it and bring it into the digital environment so it's going to look
like the dentist took a digital impression in the mouth it's just that we had to do it ourselves and
it's not quite as accurate as if the dentist is in the mouth to be honest because there's distortions
and poly vinyl and dental stone there's the articulated model so now we're going to be able
to scan that from the side and now we can see exactly how much reduction we have between that
prep tooth and the opposing to no more guessing on our part and this is one of the big benefits
for dentists who have digital impression scanners is that they can see their reduction actually in
the mouth we're going to mark the margin here and move it around and try to be true to it as long
as the dentist has left us enough room which this dentist really did you can see we've got an ideal
anatomical pattern that it's going to propose for that particular crown if there's not enough room
that it has to start making changes we can make little changes here prove the doctors request
if we need to on the contacts but most of the time with us designing it the same way every
time most doctors don't have us make many changes you can see that the different crown designs here
are all being nested these are all going to be a two crowns for example and so unlike Emacs which
is milled in a small block blocks or crowns are milled from a big white hockey puck so we do a
bunch of shades a bunch of crowns at the same time so here's that one you can see there's a
barcode that has to be matched up that's the enlargement factor because believe it or not
well one of the things that we hear about these crowns is that oh they fit better than any crown
I've had before from you guys the amazing thing is you can see here they're milled roughly 21 22
percent bigger than the final crown is going to be and that's what the enlargement factor refers to
so there's an exact factor for each block based on the weight and density of the zirconia once
that's been measured that's what that barcode tells the milling machine so it knows exactly
how much bigger to make those crowns you can see they look huge they look like veterinary crowns
they don't look like human crowns and they're going to shrink while they're in the oven and
amazingly they're going to end up fitting just fine when we go to you when you go to try them
in the mouth so the cut cut sprues are removed they're cut out of the disk and they're put on
those little alumina oxide balls that you can see there because these are going to shrink roughly
21% while they're in the oven for nine hours we need those little ball bearings to help so
that when the crown actually shrinks there's no contact between the tray and the crown or else it
would distort the shape of it so this way as the crowns shrink during the nine hours Center those
ball bearings roll underneath the crown so the crown ends up being exactly the same shape it just
shrinks by whatever 21 to 22 percent based on the exact enlargement factor for that particular block
once it comes out we do a little sandblasting to get it all cleaned up and now we're going to put
some color on it so this is some staining that's being done to match whatever color the dentist has
requested the block started off as an aide to but there's still a degree of characterization that
needs to be done typically we're going to have some translucency by the cus tips and we're going
to have some increased chroma in the gingival third here we're spraying the glaze on this is
what relah and gordon christensen aren't huge fans of because that glaze we put on there that
makes it look pretty when it comes out of the oven that glaze actually is rougher has bigger
particle size and is rougher than the zirconia oxide underneath and so really the only reason
that a Brooks our crown initially wears opposing enamel is because of that glaze on the outside and
as the result Rella has asked us is there any way you can guys can just polish the outside of those
crowns so for any doctor who asks for it we do just polish the outside of the crown without
any glaze it's not as pretty but it doesn't where the opposing it all without the glaze as part of
our quality control we use the Vita ez shade to verify that it is in fact an a2 crown before we
send it out to the doctor and color a little bit different that's why we like this computer device
to make sure that we're sending out the crown in the exact same shade that the doctor requested
you