Zirconia Marginal Chipping when milling

Our lab uses Sirona's inLab MCXL for milling, and have had some issues with milling zirconia crowns. We are having problems with marginal chipping during the milling process. When a prep doesn't allow much space for the margin thickness we usually bulk it out a bit, but that creates a lot of extra grinding time. But my question is would anyone know what might be causing the chipping of the margings when being milled? The machine is calibrated once a week, and we keep the burs fresh, but still...See more

September 26, 2013

There are 3 answers
  • Michael E. Grable · Owner/Vice President at Baran Dental Lab & Milling Center

    We don't use sirona, however with our system we stopped using the systems tools and when with a third party. We have eliminated chipping almost totally, and the tools are now in use 3 times as long. As for the chipping it might just be the mill itself. Try your spindle is it running true?


  • Christopher Nelson, CDT · Owner at Nelson Dental Laboratories

    We don't use Sirona but rather Amann Girrbaach. I occasionally get a chipped margin but it is usually due to dull burs or someone touching the machine during a program. If you are using fresh burs and the machine is calibrated properly, I question the quality of the bur and the spindle.

  • Scott Dellisola, RDT · Owner at Dell Dental Studio

    Hi my experience with Sironas in lab system is that its a cheap system never seen a great fit never mind its milling capabilities. sell it .

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