The effect of selective die spacer placement techniques on the seatability of castings.

It has been reported in the literature that impingement of the casting at the axial-occlusal line angle of the tooth preparation may be a major cause of incomplete seating following cementation. It has been suggested that an additional coat of spacer applied to these areas on the laboratory die before the fabrication of the casting may alleviate this discrepancy. This study evaluated the effect of three die spacer placement techniques on the seatability of cemented castings. Results showed no statistical difference in seating between castings made with conventional relief and those made with additional relief at the axial-occlusal line angles. Castings relieved exclusively at the axial-occlusal line angles exhibited significant post-cementation marginal openings.