Influence of CAD/CAM systems and cement selection on marginal discrepancy of zirconia-based ceramic crowns.
OBJECTIVE
To analyze the effect of ceramic manufacturing technique and luting cement selection on the marginal adaptation of zirconium oxide-based all-ceramic crowns.


METHODS
An extracted mandibular first premolar was prepared for a complete coverage restoration and subsequently duplicated 40 times in a liquid crystal polymer (LCP). All-ceramic crowns (n = 10) were fabricated on 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 restorations (n = 5) were cemented on their respective dies with glass-ionomer cement (Ketac Cem Aplicap) and resin cement (Panavia 21). The absolute marginal discrepancy of the crowns was measured before and after cementation by scanning electronic microscopy at 160 points along the circumferential margin. The data were analyzed using one-way ANOVA for repeated measures and for independent samples, Scheffé's multiple range post hoc test, and Student's t-test (alpha = 0.05).


RESULTS
There were statistical differences in the mean marginal openings among the four all-ceramic systems before and after luting (P < 0.0001). The Procera restorations had the lowest pre- and post-cementation values (P < 0.0001). A significant increase in the marginal gap size caused by luting media occurred in all tested groups (P < 0.0001). Resin cement resulted in larger marginal discrepancies than glass-ionomer cement (P < 0.0001).
Department of Orofacial Prosthesis, Faculty of Dentistry, University Complutense of Madrid, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain. framarti@odon.ucm.es
Francisco
F
Martínez-Rus
María J
MJ
Suárez
Begoña
B
Rivera
Guillermo
G
Pradíes
D000537:Aluminum Oxide / Q000737:chemistry; D001641:Bicuspid; D002484:Cementation / Q000379:methods; D017076:Computer-Aided Design; D003442:Crowns; D003738:Dental Cements / Q000737:chemistry*; D018772:Dental Marginal Adaptation; D003776:Dental Porcelain / Q000737:chemistry*; D017267:Dental Prosthesis Design; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D008277:Magnesium Oxide / Q000737:chemistry; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D003765:Models, Dental; D010710:Phosphates / Q000737:chemistry; D011076:Polycarboxylate Cement / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D013499:Surface Properties; D019231:Tooth Preparation, Prosthodontic / Q000379:methods; D015019:Yttrium / Q000737:chemistry; D015034:Zinc Oxide / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry*
D003738:Dental Cements; D005899:Glass Ionomer Cements; C485633:In-Ceram Zirconia; C093719:Panavia TPN-S; D010710:Phosphates; D011076:Polycarboxylate Cement; D011108:Polymers; D019279:Resin Cements; C422409:liquid crystal polymer; C499362:yttria stabilized tetragonal zirconia; D003776:Dental Porcelain; D008277:Magnesium Oxide; D015019:Yttrium; C040235:Ketac-cem; D015040:Zirconium; D000537:Aluminum Oxide; C028541:zirconium oxide; D015034:Zinc Oxide