Only the screws hold them in place with engaging as well. The anti-rotational aspect is for seating correctly rotated and keeping it correctly rotated. The use of mulitple abutments replaces this feature.
To add to what JMN already mentioned: On implants like Straumann, 3i and Noble, which all have long antirational interfaces, you do get lateral stability, when using hexed vs non hexed. On most platforms, the non hex abutments don't offer any lateral stability and it falls back onto the screws. So, while it wont be 'stronger', a hexed abutment, in two unit bridge for example, will offer a better lateral stability. But it also comes down to how divergent the implants are placed. Sometimes you need to cut anything protruding from the abutment in order to seat the bridge.,
DESS has non engaging Astra EV tibases- both for straight and angle base - click the link for the catalog - https://bit.ly/31AlVW3
I never come up with the option 3 idea by myself. Thank you, learn something new everyday.
This is how I do all my screw retained individual crowns as well..but after I glaze and verify contacts then I will cement crown onto Titanium abutment in the lab. I haven't used a ti-base in 5 years...always custom milled titanium abutments.
