الفهرس | Only 14 pages are availabe for public view |
Abstract Statement of the problem: Polyetheretherketone (PEEK) as a fixed dental prosthesis has been widely used, however insufficient information is available to compare the precision of the margin and internal fit of this material as a function of different construction techniques. Aim: To evaluate the influence of different fabrication techniques on the marginal accuracy and internal adaptation of PEEK molar single-crowns. Materials and Methods: 20 PEEK crowns are constructed by 2 different fabrication methods and divided in to 2 groups n=10 (PEEK CAD and PEEK Pressed). PEEK CAD crowns were numbered from 1-10 While PEEK Pressed crowns were numbered from 11-20, where each group has 10 crowns and both are constructed over a master die. For the PEEK CAD crowns, the master die was sprayed with scan spray and scanned by 3shape E4 scanner TRIOS®3. And designing was done by Ceramill4E2 Exocad CAD/CAM Software and using 4 –axis milling machine. For the PEEK pressed crowns, Wax copings were milled using same STL file with the same dimensions used for scanning, designing, and milling of the previously constructed CAD-CAM PEEK Crowns. Silicone replica bodies were constructed and sectioned in bucco-lingual direction into 2 halves for internal fit measurements and marginal accuracy was measured by using 3 equidistant landmarks along the cervical circumference for each surface of the specimen using digital microscope. Each specimen was photographed using The Microscope Leica L2 APO* at magnification 16 X which is connected to acer computer where images are processed by Leica Application suite (LAS) Version 4.0 software.Results: For Marginal accuracy, PRESS group recorded statistically significant higher marginal gap mean value than CAD group. So Milled PEEK showed better marginal precision than pressed ones. For Internal fit, no statistically significant difference between CAD group and PRESS group was recorded. At significance value (2 tailed P- value) =0.21 (p>0.05). Conclusions: PEEK CAD crowns showed superior marginal accuracy and almost equal in internal fit compared to PEEK pressed crowns. Both materials showed marginal accuracy and internal gap values within the clinically acceptable values which are less than 120µm. |