Sirona does not make a 3.0mm tibase for Astra... but BSB has made one that fits the e.max abutment blocks. It has a bit narrower platform as well.
I inherited this case from my orthodontist. I would have placed a 3.5/4.0... but that's besides the point.
It was a little tricky to seat, but in the end, it turned out great. The abutment was an e.max CAD MO1 and the final crown was e.max Impulse Value 2.
Just another option when you need it.