Best way to work off margin after sintering

[grabo]

Hi there i was wondering what is the best way to work of the margin of a zirconia coping after it has been milled and sintered, im always left with a thin margin that i have to work off!
When i mill out of metal i have the same result a small collar around margin !
Is there a way to design it that i dont get this collar ?
Regards
Graeme

 

[Labwa]

Get a kit like this:
Brasseler USA
The extra bulk at the margins are to stop the material chipping (if Zr) or bending/flexing (if metal) during milling.
There is not a lot you can do about it other than remove it by hand after the fact. you will appreciate if you ever mill yourself and try milling with no offset.
Good luck.

Lachlan.

 

[grabo]

Thanks labwa

 

[ts4341]

Save yourself some $$$, Dental Lab Supplies at Talladium, Inc.
and some of these work well http://www.xpdent.com/catalogs/bredent/burdiscs/diagen-burdisc.aspx?sm=k_e

 

[CoolHandLuke]

yes it is a safety thing, to prevent remakes, however it can be reduced to 0 depending on your system for designing.

in 3shape, you want to change the 2 settings: Margin Line Offset, and Extension offset. by default they should be set at 0.2mm each. you can safely reduce this number as far as 0.1mm each if you have a very good mill, with no vibration and new tools every week.

if you are milling PMMA, these two settings can be reduced all the way down as far as the software will let you (0.02mm each) and you can get razor thin edges. recommended for milling veneers. just be VERY careful not to place the sprues for these cases near the margin. you will get difficulties trimming them down.

IF you mill razor edges for investing in lost wax casting, i also recommend milling "lingual" bands above the margins. in order to acheive this, use the Anatomical coping software and bring the margin line up from the actual margin, to just below the area where porcelain will be added. it may not be esthetic, but it will mill.