The central concept of all-on-four to dental implants to fabricate “permanent teeth” consist, in general terms, placing two straight implants and two angled.
What Concerned Me About This Patient:
1. Avoiding a cantilever on the last few teeth can prevent fracture of the prosthesis
2. Six implants provide a better prognosis long term. In the case one implant was to fail, the prosthesis continues to work well. In the case of 4 implants, the situation is over.
3. Whenever the patient has bone available, it is easier to place straight implants and more comfortable to restore, in my hands.
4. This patient is a clencher and bruxer
5. For this patient, I went one step further. I planned to do an implant level prosthesis and avoided using multi-unit abutments. This step has worked well for me, and the patient.
Opinion: What I like the most doing it this way is that the implant screw is much longer, thicker and stronger compared to the tiny screw for the multiunit abutment.
Conclusion: In my opinion, more than four implants (6 on the maxilla and 5-6 in the mandible) is a safeguard for the more prolonged survival of the prosthesis and follow the clear guidelines of recommended implants.