Millled Wax Veneers Not Fitting

[Brett Hansen CDT]

I have a 3shape scanner and a Zenotec mini mill. We have had some issues with veneers not fitting very well. This usually happens on minimum prep veneers. All our milled crowns fit great. I have been playing with the cement gap(0.01) and extra cement gap(.010) settings so they fit tighter and don't have as much "play" in them, but I haven't found anything that seems to solve the issue. Anyone have any suggestions?

 

[Gru]

Same here. The only improvement I've achieved is in tilting them in the blank so they are almost horizontal, making the margin area similar to how the regular crowns mill.
Usually I just hand wax since it seems more efficient based on the time I mess with them.

 

[Sevan P]

Milling veneers are tricky, requires a 5axis for optimal results, a cam that allows for custom adjustments, like hyperdent or sum3d. Drill cop is the biggest killer in the veneer department, that is why I will only do 3/4 wrap broken contact veneers in CAD. Everything else is hand waxed 100% for optimal fit. I don't waste my time with them. But they can be done, i think some pics of the die spacer in cad and drill comp and general pics will help solve your issue. can you post some?

Tighter die spacer is going to make it worse, first lets get you fitting then you can tighten up as needed, this isn't a singe step process, cut and test fit till you get your results.

 

[Brett Hansen CDT]

Thanks guys. We are now hand waxing all our veneers.

 

[Sevan P]

Thanks guys. We are now hand waxing all our veneers.

It is just best for a much better result. Sharp edges and a nasty thing in CAD/CAM.

 

[Marcusthegladiator CDT]

I mill all the veneers. In 3shape I use a .3/.33 mm comp. Then in sum3d I program the same. Once the .6mm bur tools, it finishes off bits of the intaglio with the .3mm tool. I get a great intimate fit and I don't lose much needed material thickness to the comp. And handling the milled wax is much more forgiving than fragile hand waxed patterns. I use the grey wax from Anaxdent. It's great for milling delicate patterns.

 

[Sevan P]

I mill all the veneers. In 3shape I use a .3/.33 mm comp. Then in sum3d I program the same. Once the .6mm bur tools, it finishes off bits of the intaglio with the .3mm tool. I get a great intimate fit and I don't lose much needed material thickness to the comp. And handling the milled wax is much more forgiving than fragile hand waxed patterns. I use the grey wax from Anaxdent. It's great for milling delicate patterns.

I stated the same. I was actually speaking on your behalf....................

 

[Bumfrey]

in exocad i always take the undercut to .2mm if that helps, its default is 1mm. Unsure with 3shape settings, but it helped heaps with exocad. I have a mini too.

 

[Brett Hansen CDT]

The smallest bur my mill currently uses is 0.7 mm. When we get the upgraded software, we can use a .3mm bur. Would this help milled veneers fit better? Would a a 5 axis mill do a better job on veneers than a 4 axis?

 

[MJFDDS]

We get great fit with our milled veneers on our Versamill. Smallest tool used on the intaglio surface is 1mm, 0.6mm is used on the margin.

 

[sidesh0wb0b]

Thanks guys. We are now hand waxing all our veneers.

if you dont mind sharing....for your full contour milling have you been able to get rid of the 'play' in the fits?
still tweaking mine, but not 100% satisfied just yet. if you feel like sharing your parameters that work best for you that would be great. i can post mine too, but as i said im not quite where i want to be

 

[Brett Hansen CDT]

I use .010 mm cement gap and .040 mm extra cement gap on all my Zirconia crowns. If I am designing a crown on a custom abutment, I decrease the extra cement gap to .030 mm. If I am designing a crown on a stock abutment, I decrease the extra cement gap to .010 mm. I don't play with the rest of the parameters.