Chipped margins ?

[DentalTechAeea]

Hello!

Can somebody give me an advice?

I have made a full contour crown in pritidenta blank 4 times and the margins are chipped in diferent areas , the problem is from the milling machine?(SIRONA Inlab McX5) or the blank? The burs are not very used and this happened only at this crown.(it’s a shoulder margin preparation)

Thank you!

 

[RCKSTR]

what is the thickness of the margin? What is your margin offset angle? Does the prep have any steep rises in it? A picture would be helpful.

 

[CoolHandLuke]

you might be milling too quickly, or not quick enough. you might need new coolant, you might need the machine's tool collets to be tightened.

lots can be happening.

 

[Car 54]

Just for curiosity sake, have you tried milling the same crown with a different zircona disc? If everything's been milling fine up to this point, maybe it's worth a shot?
Otherwise, the members who've posted above have a better handle on theses things than I do.

 

[CoolHandLuke]

its sirona. it doesnt mill discs. these are priti blocks.

it would make a bit of sense if the blocks were slightly misaligned in the holder. but thats not entirely possible without a highly damaged machine.

 

[Car 54]

It just mills blocks?

 

[CoolHandLuke]

and not very well.

 

[Car 54]

And I suppose if I would've read the original post better, where OP stated "blank", two times (not disc),may have helped

 

[CoolHandLuke]

dont worry i managed to ignore the phrase " i have nothing to do with dentistry" and still ask a poster about his lab.

 

[Magdalena]

Hello!

Can somebody give me an advice?

I have made a full contour crown in pritidenta blank 4 times and the margins are chipped in diferent areas , the problem is from the milling machine?(SIRONA Inlab McX5) or the blank? The burs are not very used and this happened only at this crown.(it’s a shoulder margin preparation)

Thank you!

Dear User,

I am sorry to hear about your issues with chipped margins. I have discussed this with our technical engineers and based on their feedback and the experience from other users that mill our priti®multidisc ZrO2 in a SIRONA McX5 I would like to pass on the following advice:

1. For milling priti®multidisc ZrO2 we highly recommend to use coated tools only. Our users achieved good results using the following items:
6572932 (Bur 2,5 ZrO2 DC)
6572940 (Bur 1,0 ZrO2 DC)
6572957 (Bur 0,5 ZrO2 DC)

2. We recommend the milling strategy Soft (instead of the strategies normal or fast)

3. Edge reinforcement and flank width of the restauration in the CAD should be 150µm

Please note that these suggestions work with software versions from SW16 on.

Please let me know if there is anything else we can assist you with.

 

[CreDes]

If there is margin chipping I would look at the but life, margin thickness, and speed. I would thicken the margin more than the 150 that Sirona recommends.

 

[JMN]

dont worry i managed to ignore the phrase " i have nothing to do with dentistry" and still ask a poster about his lab.

His business was flat.