Three-dimensional finite element analysis of the effect of incomplete seating of cemented fixed dental prostheses.

: This study investigated the stress distribution patterns of two finite element models of a stylized fixed dental prosthesis-cement-abutment tooth system, one with the prosthesis completely seated and the other manipulated to be incompletely seated. Maximum equivalent von Mises stress varied according to direction and location of load, with vertical loading of the pontic of the completely-seated FDP (2.9 MPa) and oblique loading of the premolar of the incompletely-seated FDP (80.8 MPa) producing the least and the highest values, respectively. Total deformation of the restored system showed variations, although different cements had minimal effect on stress and on deformation. Under the conditions studied, a fixed dental prosthesis that had not been verified as fully seated on its abutments prior to cementation, could, with repeated loading cycles, be predicted to suffer a greater risk of fatigue, and thus clinical failure.