All On 4 Technique

Peter, a dentist from the Netharlands, asks:

I trying to form my opinion on the ‘All On Four’ concept by Nobel Biocare. However, it is very difficult to find good data on the subject.

Everything looks fantastic, but my gut feeling tells me otherwise. I know gut feeling isn’t very scientific, so I’d appreciate some feedback from other dentists worldwide.

Some dentists have told me that the All-on-Four on the mandible avoids bone grafting of the posterior
mandible in many cases. Is this accurate?

In addition, can anyone please walk me thru exactly tell me how this works? Are impressions taken for
dentures (to address the out of line bite and sagging facial muscles),
with these then being incorporated into a bridge ready for fitting? I’m
finding it difficult to accept that aesthetics may well be lost for
stability. Can both be achieved? Thanks for any comments.