Marginal fit of anterior 3-unit fixed partial zirconia restorations using different CAD/CAM systems.
OBJECTIVE
Few studies have investigated the marginal accuracy of 3-unit zirconia fixed partial dentures (FPDs) fabricated by computer-aided design/computer-aided manufacturing (CAD/CAM) system. The purpose of this study was to compare the marginal fit of zirconia FPDs made using two CAD/CAM systems with that of metal-ceramic FPDs.


METHODS
Artificial resin maxillary central and lateral incisors were prepared for 3-unit FPDs and fixed in yellow stone. This model was duplicated to epoxy resin die. On the resin die, 15 three-unit FPDs were fabricated per group (45 in total): Group A, zirconia 3-unit FPDs made with the Everest system; Group B, zirconia 3-unit FPDs made with the Lava system; and Group C, metal-ceramic 3-unit FPDs. They were cemented to resin dies with resin cement. After removal of pontic, each retainer was separated and observed under a microscope (Presize 440C). Marginal gaps of experimental groups were analyzed using one-way ANOVA and Duncan test.


RESULTS
Mean marginal gaps of 3-unit FPDs were 60.46 µm for the Everest group, 78.71 µm for the Lava group, and 81.32 µm for the metal-ceramic group. The Everest group demonstrated significantly smaller marginal gap than the Lava and the metal-ceramic groups (P<.05). The marginal gap did not significantly differ between the Lava and the metal-ceramic groups (P>.05).


CONCLUSIONS
The marginal gaps of anterior 3-unit zirconia FPD differed according to CAD/CAM systems, but still fell within clinically acceptable ranges compared with conventional metal-ceramic restoration.
Seoul Highan Dental Clinic, Daejeon, Republic of Korea.
Tae-Jin
TJ
Song
Taek-Ka
TK
Kwon
Jae-Ho
JH
Yang
Jung-Suk
JS
Han
Jai-Bong
JB
Lee
Sung-Hun
SH
Kim
In-Sung
IS
Yeo
CAD/CAM; Marginal fit; Zirconia FPD