The effect of cement volume on crown seating.

This in vitro study examined the effect of cement volume on the seating of complete crowns. A spaced complete crown was made to fit a nickel-chromium replica mounted in a cementation jig that allowed static and dynamic seating. The crown was luted 10 times for each group using zinc phosphate cement under an initial static load followed by a dynamic load of 1,500 Hz. Seating was measured by a linear variable differential transducer. Mean vertical discrepancies for the three cement volumes were: completely filled (90.0 +/- 15.2 microns); half filled (42.1 +/- 8.6 microns); and brushed on (27.4 +/- 7.2 microns). Means differed significantly (P < .0005). This study indicated that a thinly brushed-on layer of luting cement gave smaller vertical seating discrepancies than greater volumes of luting cement.