Implant below the alveolar bone crest: will it cause problems?

Implant could have been placed a lil more mesially. Other than that, no other issues.

Expect bone die back I recommend placement at the bone level, sometimes bone will grow over the flat healing screw and it will need to removed. When this is restored most like ly will get some dieback and little saucer defect. The problem is not integration but long term perio. I would have backed it out a turn or so after seeing this post placement film, that's why the film is taken.

Is that i healing abutment or cover screw? I would be concerned about getting a good emergence profile in this case.

Go deep!

There will not be any problems due to this subcrestal placement. Problem could be to place a healing abutment as there is a widening oh the component. You could just widen the osteotomy mouth to accomodate an anatomical abutment and enjoy a perfect emergence .

There should be no problem at all . In fact subcrestal platform position decreases compressive forces on the crest thus less resorption

I think the implant is well placed.... a wider diameter implant could have been used...but this you will consider for the next case. If you are concerned about the mesially tipped second molar...it is simple to correct.... after the implant is well integrated, place an abutment and a plastic temporary crown....have the patient back a few days later.... remove the temporary crown, add a touch of acrylic resin at the distal contact of your temp, allow it to harden out of the mouth, and then place the implant crown back on the implant....it will be very tight...probably will not be able to put floss through the contact..... a few days later...it will become flossable.... do the same thing several times, the second molar will begin to straighten out.... in a few simple appointments, you will solve that problem.