What's your minimal thickness on lingual? I remember Dr. Ed McLaren in Chicago 2009, Packed room with everyone high on emax. We've been noticing some failures with emax. The Air left the room, Silence. What he went on to say is that Bonded is better and likely fine but maintain manufacturers minimal requirements.
Physics haven't changed and if your material is less tough than emax then you need to take that into consideration. This is where Zr fits in perfectly given its strength being about 3x Lithium disilcate. A lot of cases presented on the big screens, full mouth rehabs, are vertically opened dimensions which is a World away from Quadrant dentistry and single units. We refuse emax Rx's that are below min thickness period. Love Lithium disilcate products but need to respect their use. Less than required tolerances and you'll see that crown again as a rush remake down the road and none of us need that. Oh, and is there a charge for that? Stay safe and choose appropriate materials, not necessarily what's hyped.
We have a number of new Dr.'s and they need some coaching on this. With Zr, we generally need about .4-.5mm thickness at min, .6mm posterior occlusal. Some have difficulty with that. I remind them that if they were to Rx's a PFM then they'd have to prep an additional 1 mm. I truly wish self limiting burs were a part of dental training, would save so much angst. I know Dr. Robert Winter has some beauty's available through Brasseler.