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KMID : 0362420090470020148
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Journal of Korean Academy of Prosthodontics
2009 Volume.47 No. 2 p.148 ~ p.155
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A comparison of the fidelity of various zirconia-based all-ceramic crowns fabricated with CAD/CAM systems
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Kim Sung-Jun
Jo Kwang-Hun
Lee Kyu-Bok
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Abstract
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Statement of Problem: The interest in all-ceramic restorations has increased as more techniques have become available. With the introduction of machinable dental ceramics and CAD/CAM systems there is a need to evaluate the quality levels of these new fabrication techniques.
Purpose: This study is to evaluate the crown fidelity (absolute marginal discrepancy and internal gap) of various zirconia-based all-ceramic crowns fabricated with different CAD/CAM (computer-assisted design/computer-assisted manufacturing) systems and conventional cast metal-ceramic crowns.
Material and Methods: A resin tooth of lower right second premolar was prepared. After an impression was taken, one metal master die was made. Then 40 impressions of metal master dies were taken for working dies. 10 crowns per each system were fabricated using 40 working dies. Metalceramic crowns were cast by using the conventional method, and Procera, Lava, and Cerec inLab crowns were fabricated with their own CAD/CAM manufactruing procedures.
The vertical marginal discrepancies and internal gaps of each crown groups were measured on a metal master die without a luting agent. The results were statistically analyzed using the one-way ANOVA and Tukey’s HSD test.
Results: 1. Vertical marginal discrepancies were 50.6 ± 13.9 ㎛ for metal-ceramic crowns, 62.3 ± 15.7 ㎛ for Procera crowns, 45.3 ± 7.9 ㎛ for Lava crowns, and 71.2 ± 2.0 ㎛ for Cerec inLab crowns. 2. The Internal gaps were 52.6 ± 10.1 ㎛ for metal-ceramic crowns, 161.7 ± 18.5 ㎛ for Procera crowns, 63.0 ± 10.2 ㎛ for Lava crowns, and 73.7 ± 10.7 ㎛ for Cerec inLab crowns.
Conclusion: 1. The vertical marginal discrepancies of, 4 crown groups were all within the clinically acceptable range (120 ㎛). 2. The internal gaps of LAVA, Cerec inlab, and metal-ceramic crowns were within clinically acceptable range except Procera crown (140 ㎛).
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KEYWORD
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CAD/CAM system, zirconia, internal gap, vertical marginal discrepancy
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