الفهرس 
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Abstract
”Objectives: The purpose of this In-vitro study was to evaluate the effect of different wax pattern construction techniques on marginal accuracy and internal fit of Celtra press crown restorations. Materials and methods: A maxillary 1st premolar was selected and prepared to receive all ceramic crown restoration, 30 identical dies of the prepared tooth were printed using 3D printing resin and divided into 3 groups according to wax pattern fabrication technique. group C: conventional, group S: Subtractive, group A: additive wax pattern. Vertical marginal gap of each wax pattern on its corresponding die was measured using USB digital microscope with built-in camera. All wax patterns were sprued, invested, pressed with Celtra press restoration and cemented on their corresponding dies according to manufacturer recommendation. Vertical marginal gap of all specimens was measured before and after cementation. Internal adaptation was evaluated using replica technique. Data were collected, tabulated and statistically analyzed using Tukey post-hoc test (P= 0.05). Results: The results showed that there was a statistical significant difference between the three groups regarding the vertical marginal gap distance and internal adaptation. The highest mean marginal and internal gap values were found in group C followed by group S while the lowest value was found in group A. Conclusion: 3D printed wax pattern construction technique resulted in the highest marginal and internal adaptation of crown restorations compared with conventional and subtractive techniques. ”