Imagine this, you spend a lot of time, energy, and money to mill a dental bridge. You put it in the sintering furnace when you leave the office. The next morning you open the sintering furnace and find a broken long bridge. Of course, we all do not want this. But sometimes things don't always go as planned. There are several reasons why a long bridge fails, for example, low quality zirconia block, poor design, wrong placement of the dental bridge. While there is still one factor we maybe neglect, a simple one, you put too many sinter beads when sintering.
It's a very simple rule in physic, the higher friction the higher resistance. Imagine you're walking in the desert, if the sand is too thick, it's easy to get stuck and it is hard for you to walk. The same happens when sintering. If you put too many zirconium oxide beads in the zirconia sintering tray, the long bridge will have more resistance, thus it might cause long bridge breaking. So the next time you're sintering, remember don't put too many zirconium beads.