What instruction should be given to the laboratory to improve the success of an implant-supported bridge?

Correct answer: C. Fabricate the crowns so that occlusal forces are directed along the long axis of the implants

• A. Steep cusps generate LATERAL forces during excursions — exactly what implant-supported restorations are designed to avoid. Cuspal inclines are deliberately shallowed and occlusal tables narrowed.
• B. The dentist owns the treatment plan and the occlusal scheme. Delegating design decisions to the laboratory abdicates clinical responsibility.
• C. CORRECT. Implants have no periodontal ligament, so they cannot sense or dissipate lateral load the way natural teeth do. AXIAL loading directs force down the implant body into bone that is well adapted to compression. Off-axis force creates bending moments concentrated at the crestal bone and the abutment screw, causing crestal bone loss and screw loosening or fracture.
• D. Embrasures must be OPEN for hygiene access. Closing them makes peri-implant maintenance impossible and invites peri-implantitis.

Note: Implant protective occlusion in summary: narrow the occlusal table, shallow the cusps, direct forces axially, use light centric contacts with no contact in excursions on the implant, keep embrasures open, and eliminate cantilevers wherever possible. The absence of a PDL means no proprioceptive feedback — patients genuinely cannot feel that they are overloading the implant.