Re: New trend - CNC in Dentistry

>"Marcus and Eva"
> It's kind of neat in terms of the gadgetry that was developed for

it, but it

> makes pretty crappy restorations.
> The fit is terrible, and the adhesive is routinely used to fill the

gaps,

> making for a much higher incidence of postoperative problems

including

> intractable sensitivity and recurrent tooth decay.
> "Tis a great gimmick though, and really brings 'em in the door.
> I'm not a fan, and I'd certainly never accept one in my mouth or

inflict one

> on a patient.

How current is your information on this, sounds like you have been
out of it for awile...I was about to have this procedure done. If
you know this is still true i will go with the conventional
casting...At 2X the price....

Wally











--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Marcus and Eva"
<implmex@a...> wrote:

> Hi Andrew:
> The material is actually a Zirconium based ceramic that's not really
> porcelain, but is tooth coloured and can be cut with diamond plated

points

> and wheels.
> I know this technology well; I was a dentist for a good stretch

before I

> went back to my first love.
> It's kind of neat in terms of the gadgetry that was developed for

it, but it

> makes pretty crappy restorations.
> The fit is terrible, and the adhesive is routinely used to fill the

gaps,

> making for a much higher incidence of postoperative problems

including

> intractable sensitivity and recurrent tooth decay.
> "Tis a great gimmick though, and really brings 'em in the door.
> I'm not a fan, and I'd certainly never accept one in my mouth or

inflict one

> on a patient.
> If you're interested in reading the hype, do a search for Siemens
> Cerec...that's the company and the product.
> They make it sound like the next wonder of the world...but then,

they want

> to move plenty of those $100,000.00 machines!!
>
> The technique you refer to, is the time honoured Porcelain Fused to

Metal,

> or PFM crown.
> When properly made, this is a very reliable restoration, and is

still the

> treatment of choice for full crown restorations in visible areas of

the

> mouth.
> The metal base gives it some ductility, the casting process is FAR

more

> precise than CNC milling on such an irregular shape, and the tooth

doesn't

> need to be hacked into nearly as aggressively.
> It's also impervious to cracking, even though the porcelain can

become

> detached, leading to a cosmetic problem but not a functional

problem.

> The alloy used for the base is a high noble alloy with gold, copper,
> palladium, and some other stuff in it to help make the porcelain

fuse to it.

> The porcelain is sculpted and baked on and glazed...very demanding

work to

> do really well.
> Dental technicians are among the most underappreciated craftspeople

around!!

>
> Cheers
>
> Marcus