Sameer Puri D.D.S. In the 4.02 software update, one little feature that we now have is the ability to track how many times the burs have been used. In the Mill Preview, in the Restoration step menu, prior to hitting Start to begin the milling, you will see (as indicated by the arrow) the number of mills each bur has. This allows you to keep track of the bur usage and change it out regularly.
The question that arises is how many times should you use a bur before you swap it out? There has been a lot of research done on this internally by Sirona, and the consensus is that after about 20 mills, you should swap out your burs. There is a tremendous amount of wear after 20 mills, and not only does it affect the time it takes to mill (your indicator says six minutes to mill but it actually takes eight – this is a sign of worn burs) but you can have increased chipping at the margins. Worn-out burs will tend to chip your restorations and leave a slightly rougher surface if you push the limits with them milling. So once you hit 20 mills, change out your burs. If you are at 18 mills and one bur goes bad, change them both out. Keep things consistent and simple.
