Evaluation of the absolute marginal discrepancy of zirconia-based ceramic copings.
BACKGROUND
Marginal fit is an important factor for the long-term success of ceramic restorations; however, it is difficult to compare results from studies on marginal accuracy of zirconium oxide-based restorations that used various computer-assisted systems, because different methods were used to obtain the data.


OBJECTIVE
The purpose of this study was to analyze the effect of different manufacturing techniques on the marginal adaptation of zirconia ceramic copings.


METHODS
An extracted mandibular first premolar was prepared for a complete coverage restoration and subsequently duplicated 40 times in a liquid crystal polymer (LCP). Ceramic copings (n=10) were fabricated on the LCP models using the following systems: glass-infiltrated zirconia-toughened alumina (In-Ceram Zirconia) and yttrium cation-doped tetragonal zirconia polycrystals (In-Ceram YZ, Cercon, and Procera Zirconia). The absolute marginal discrepancy of the cores was assessed by using an image analysis system. The data were analyzed using 1-way ANOVA and Scheffé's test (α=.05).


RESULTS
The mean marginal openings were 29.98 ± 3.97 μm for the In-Ceram Zirconia group, 12.24 ± 3.08 μm for the In-Ceram YZ group, 13.15 ± 3.01 μm for the Cercon group, and 8.67 ± 3.96 μm for the Procera group. Significant differences were found among the 4 systems (P<.05).


CONCLUSIONS
The marginal accuracy achieved for the 4 zirconia-based ceramic crown systems analyzed was within the range of clinical acceptance (120 μm).
Department of Buccofacial Prostheses, Faculty of Odontology, University Complutense of Madrid, Madrid, Spain. framarti@odon.ucm.es
Francisco
F
Martínez-Rus
María J
MJ
Suárez
Begoña
B
Rivera
Guillermo
G
Pradíes
D000704:Analysis of Variance; D001641:Bicuspid; D017076:Computer-Aided Design; D003442:Crowns; D018772:Dental Marginal Adaptation; D003776:Dental Porcelain; D017267:Dental Prosthesis Design; D003799:Dental Stress Analysis; D006801:Humans; D008422:Materials Testing; D017755:Prosthesis Fitting; D018709:Statistics, Nonparametric; D015040:Zirconium
D003776:Dental Porcelain; D015040:Zirconium; C028541:zirconium oxide