Reassessment of die-spacer with dynamic loading during cementation

The authors previously reported a reduction in crown seating discrepancies of approximately 200 microns resulting from the application of dynamic forces during cementation. Previous in vitro die-spacer studies used static loads with large seating discrepancies unrepresentative of clinical practice. This investigation reassessed paint-on die-spacer for its effect on completeness of seating and retention when dynamic seating was used. A series of seven complete crowns was made for each of three extracted human teeth by using 0 to 6 coats of spacer. Index marks were used to measure crown position before and after cementation. Mean seating discrepancies indicated complete seating for all groups of crowns irrespective of the number of coats of die-spacer. An analysis of variance demonstrated no significant differences in the degree of seating. However, crowns made from dies without spacer were significantly more retentive (p less than 0.05) than those made from spaced dies.