Marginal fit of leucite-glass pressable ceramic restorations and ceramic-pressed-to-metal restorations.
BACKGROUND
Fabricating a feldspathic porcelain margin on a metal-ceramic restoration with a clinically acceptable marginal fit has proven to be a technique-sensitive procedure. Pressable ceramics are advocated to solve this problem.


OBJECTIVE
The purpose of this in vitro study was to compare the marginal adaptation of a pressable ceramic system when used with both all-ceramic and metal-ceramic crowns, with a traditional metal-ceramic restoration.


METHODS
A 1.5-mm, 360-degree chamfer margin was prepared on a typodont maxillary central incisor. Polyether impressions were made and poured in a Type IV dental stone, and the following crowns were fabricated on individual dies: 15 metal ceramic restorations (MCR) (Ceramco II, Ceramco, and Argelite 60), 15 pressed-to-metal restorations (PTM) (CPC-MK, and Argelite 60), and 15 pressed ceramic restorations (PCR) (CPC-MK). The marginal fit of the crowns was evaluated every 90 degrees around the crown margin circumference under a microscope at original magnification x 45. A 1-way analysis of variance (ANOVA) was used to compare data (alpha=.05).


RESULTS
The mean marginal discrepancy for MCRs was 94 +/- 41 microm, for PTMs, 88 +/- 29 microm, and for PCRs, 81 +/- 25 microm. The 1-way ANOVA showed no significant difference between groups ( P =.568).


CONCLUSIONS
The marginal fit of pressed-to-metal (PTMs) and pressed all-ceramic crowns (PCRs) was similar to that of traditional metal-ceramic crowns (MCRs).
Goldin
Edward B
EB
New York University College of Dentistry, New York, NY, USA. edg0790@nyu.edu
Boyd
Norman W
NW
Goldstein
Gary R
GR
Hittelman
Eugene L
EL
Thompson
Van P
VP
D000538:Aluminum Silicates / Q000737:chemistry; D002516:Ceramics / Q000737:chemistry; D003442:Crowns; D018772:Dental Marginal Adaptation / Q000592:standards*; D017267:Dental Prosthesis Design; D006801:Humans; D008422:Materials Testing; D016876:Metal Ceramic Alloys / Q000737:chemistry*
D000538:Aluminum Silicates; D016876:Metal Ceramic Alloys; C078519:leucite