Ti bases too tight.

[Terry Whitty]

Hi all and happy new year.
A collegue rang me today telling me all his Ti bases are too tight in his Zir implant crowns.He thought it could be his sintering technique. I suggested he mill a file with some PMMA and try the fit, if its ok he may have a sintering issue if not he may need to look elsewhere.

He uses 3 Shape Dental Designer, any one have any comments or suggestions.

Thanks in advance!

 

[James Kivimaki]

I had a situation where the mill was milling the interface to exactly ( no over mill) and I could not get anything to fit without adjustment. I had our guy make us a new milling strategy that over milled slightly and that took care of the issue. This was just my experience and it was with an old version of 3 shape.

 

[Terry Whitty]

Hi James, thanks for that... i was also thinking along those lines.. If the two are too exact I would imagine they will never fit , you would need some offset.
Adjustments to milling strategy could do it for sure.

 

[RJS8669]

Same here. Milling strategy needed some tweaking - that's all...

 

[Terry Whitty]

Same here. Milling strategy needed some tweaking - that's all...

Thanks for that

 

[KentPWalton]

Make sure he is using new tools. Worn tools will cause fit issues.

Plus, he needs to make sure he's using the correct CAM strategy for the

abutment/crown utilizing the correct tools to be able to reach the areas.

 

[NicelyMKV]

Whose CAD design library is he using?

 

[CoolHandLuke]

may want to check and ensure he is cleaning all zirconia dust out of the milled area before sintering.

just to ensure procedural accuracy.

 

[lcmlabforum]

Just how much cement space are you allowing? Most Ti Bases are so short, if they rely on cement
to stay on, would likely fail in function. Good old days when we talked about Zinc phosphate cement
down to 25 microns, but not so sure for MultiLink Implant cement or the latest version . . .
LCM

 

[JohnWilson]

Simulate, simulate simulate don't trust your cam to know what you want. Standard deviation map will show you all the nasty little red places the bur isn't going to get to. All the key ways on most interfaces I have worked with were designed for a 1mm bur to mill them properly.

Overmilling the inside is a bandaid, using the manufacturers prespaced parameters in their corresponding library will give you a more precise fit if you understand how to manipulate your cam strats to mill clean.