Marginal Fit of Lithium Disilicate Crowns using Three Different Fabrication Techniques
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The purpose of this in vitro study was to evaluate the three-dimensional marginal fit of lithium disilicate crowns fabricated by pressed or CAD/CAM milled four- or five-axis machines. The three groups were Pressed, McX and McX5, and differed in their fabrication technique. The Pressed group was fabricated with IPS e.max Press and was heat pressed with the lost wax technique. Both of the CAD/CAM milled restorations McX and McX5 were scanned and designed using the same process and differed only in the milling machine used to fabricate them, four-axis chairside mill and five-axis laboratory mill respectively. All specimens were evaluated using the 3D replica technique, digitized and examined with a digital analysis software (Geomagic Control, 3D Systems, Rock Hill, S.C.). A mean marginal fit was acquired by the software and loaded into a statistical analysis software. The data was analyzed using a one-way ANOVA. Normality was checked using the Shapiro Wilk test for normality, and Levine’s Test was used to insure that there was homogeneity of variance. A p-value of less than 0.05 was used to determine if the difference was statistically significant. The Pressed group’s mean marginal fit was 49.37 μm. The average fit for the CAD/CAM milled restorations was 54.53 μm for McX and 50.74 μm for McX5. The results obtained indicated clinically acceptable marginal fit for all groups with no significant difference between the three fabrication methods.
Williams, Steven Andrew (2017). Marginal Fit of Lithium Disilicate Crowns using Three Different Fabrication Techniques. Master's thesis, Texas A & M University. Available electronically from