Improper fit at the abutment/- implant interface
It is very vital that the fit of the abutment is crosschecked radiographically prior to final delivery of the prosthesis. The microgap at the interface has both biologic and mechanical consequences. Not only does the crevice provide a niche for the microbial population but also leads to increased mechanical strain leading to fracture of the screw. At the impression stage also the radiographic verification of the impression transfer coping and then attachment of the implant analog without incorporating a rotational error is vital to prevent a rotational misfit of the abutment which also directly correlated to screw joint failure.