Cad/Cam

[zxc1234]

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I just heard about cad/cam computer program and mills. I was wondering what type of material the cad/cam mills use to make permanent crowns and bridges? Is this material is reliable enough to eliminate porcelein on metal crowns?

 

[Dent2011]

Maryland has several of these and second year students start learning to use them. You can use various materials that come on blocks--all depends on the type of machine you get. The difference I've seen in many types is whether or not the initial image is scanned with or without a reflective powder. They currently cost about 100g but can be less if you chose to have the image sent to an offsite lab (you don't actually own the milling machine). Pretty great technology--I would just google it to get more info!

 

[Oracle DMD]

I believe there's zirconia in the material for strength.

 

[Mcglock]

For LAVA CADCAM the material is zirconia. For Procera CADCAM the material is zirconia, alumina, or in the case of the implant bridges titanium is an option. Both of these CADCAMS only make the substructure for the crowns. They replace the metal, but not the porcelain. You still have to stack porcelain. With CEREC I believe the whole crown is zirconia, so it replaces the metal and the porcelain of PFM's.

 

[armorshell]

With CEREC I believe the whole crown is zirconia, so it replaces the metal and the porcelain of PFM's.

The whole thing is porcelain, not zirconia. CAD/CAM milling of baked zirconia copings takes hours and hours because of the hardness of the material. LAVA gets around this by milling it in the "green" soft state at larger dimension and firing it afterwards. E4D (and maybe CEREC) has a similar material called EMAX CAD specifically made for CAD/CAM dentistry, which is a porcelain milled in an enlarged size soft state then fired to harden it.

I'll tell you how the EMAX material goes in a few weeks, I'm getting an emax E4D onlay done in early March.

 

[DrJeff]

I just heard about cad/cam computer program and mills. I was wondering what type of material the cad/cam mills use to make permanent crowns and bridges? Is this material is reliable enough to eliminate porcelein on metal crowns?

This exact question came up this past weekend in the panel discussion lecture I attend at Yankee Dental in Boston. On the panel were such noteables as Dr. Ron Jackson, Dr. Dan Nathanson and Dr. Gery Kugel. The conscencious opinion was that based on current available research that their 1st choice for full coverage molar crowns would still be cast gold, then if the patient insisted on tooth colored, that traditional PFM crowns would be second in line, and lastly would be all ceramic crowns for molars - The panel felt that for pre-molars on forward in *most* clinical situations that all ceramic crowns (Zirconia, Lithium Disulfate, or pressed ceramic veneers {empress or authentic} and/or feldspathic) were the 1st choice, with PFM's being second.

The main reason for the lack of current enthusiasm from the panel for all ceramic molar crowns, even the Zirconia and Lithium Disulfate crowns was lack of LONG TERM clinical data. Short term data looks promising to date, but then again with respect to all ceramic full coverage restorations, short term data has looked good before only to get real ugly as time went on(ask a prof in his/her 40's+ about DICOR crowns😱 )

At the same meeting last week, even basically the godfather of modern dentistry, Gordon Christenson, was of the same opinion about molar region crowns in todays dental world. He basically went 1 step further in one of the lectures he gave when asked about this topic, saying that (paraphrasing here for a moment):unless the patient has a known allergy that gold full coverage restorations are the standard of care in the molar region and that the esthetics are inconsequential (literally saying "unless the patient is staring in a pornographic movie"😆) over longterm function.

 

[DLY303]

I think that seems to be a big difference in philosophy between general and cosmetic dentists. The best function is definitely not always the best aesthetically.

I spent the summer in Thailand and almost all of their big practices there are using CAD/CAM systems. They are even using them to create bonded fillings. They also seem to be doing almost all porcelain. I had some work done there and the dentists said that they almost never use amalgam or PFM anymore (not that this is good or bad necessarily).

From what little I know about CAD/CAM, the type of block used and the artistic skill of the technician is extremely important otherwise you might even up with a solid white tooth.

 

[gryffindor]

I think that seems to be a big difference in philosophy between general and cosmetic dentists. The best function is definitely not always the best aesthetically.

You can achieve excellent esthetics and great function without using CAD/CAM restorations. All-porcelain crowns have been around for years before the instant crown milling units came around.

I don't know what's up with Thailand going CAD/CAM crazy, but I am most impressed when I see Korean patients with those perfect gold inlays and onlays. Now those are some nice restorations.

 

[DrJeff]

I think that seems to be a big difference in philosophy between general and cosmetic dentists. The best function is definitely not always the best aesthetically.

I spent the summer in Thailand and almost all of their big practices there are using CAD/CAM systems. They are even using them to create bonded fillings. They also seem to be doing almost all porcelain. I had some work done there and the dentists said that they almost never use amalgam or PFM anymore (not that this is good or bad necessarily).

From what little I know about CAD/CAM, the type of block used and the artistic skill of the technician is extremely important otherwise you might even up with a solid white tooth.

Everyone participating in the panel discussion that I referenced above are considered to be leaders in modern cosmetic and restorative dentistry, but they're also big fans of evidence based dentistry, because lets be honest, what's a better restoration, one that looks PHENOMENAL and breaks within 5 years or one that looks GREAT and lasts for 20 years???? And remember, where they were advocating all gold or traditional PFM's is in the MOLAR region. Upfront, in almost all situations, all ceramic was the restoration of choice, and most of them just simply prefer pressed and/or hand layered porcelain over a CAD/CAM based milled 1 piece restoration for true life like vitality of the outer ceramic layer