Cervical discrepancies and closeness of marginal fit of full cast crowns in correlation with the luting agent used
Utz, K.H.; Grüner, M.; Vothknecht, R.
Deutsche Zahnarztliche Zeitschrift 44(11): 901-904
1989
ISSN/ISBN: 0012-1029 PMID: 2639008 Document Number: 333057
In an in-vitro study 75 extracted teeth were prepared with a chamfer and a 12 degree convergence angle. After corrective impression taking and preparation of the dies accurately fitting caps were made of "Stabilor G" alloy. The marginal defects were measured at 4 points on each tooth under the light-microscope before and after cementing with three different luting agents. Before cementation the mean values and standard deviation of the cervical discrepancies were 105 +/- 43 microns. The crowns fixed by means of zinc oxyphosphate cement (Harvard) exhibited marginal defects of 142 +/- 33 microns, those fixed with Fuji-Ionomer type I glass polyalkenoate cement had 159 +/- 20 microns, and the crowns cemented with Ketac-Cem had 127 +/- 6 microns. After exposing the specimens to thermal cycling, additional data on the sealing capacity of these cements could be obtained which showed zinc oxyphosphate cement to have the most favorable properties.