الفهرس | Only 14 pages are availabe for public view |
Abstract A major deterrent to reaching the full potential of dental CAD/CAM systems, is the possible damage induced during milling. Despite all the recent innovations and increasing robustness in the dental field, yet machining induced damage for CAD/CAM blocks is still inevitable. Any introduced damage coupled with intrinsic flaws in the ceramic material, will give rise to additional damage and ultimately clinical failure. As a result; numerous approaches have been utilized to determine the machinability of dental ceramics, in order to assess the degree of damage that can be incurred during milling. However; various factors are thought to affect the machinability of dental ceramic materials; such as machine related factors, tool related factors, or material related factors. This study was conducted to assess some of the material related factors, that are thought to affect the dental ceramic material{u2019}s machinability. This study was conducted using three different machinable ceramic blocks; the inCoris (translucent zirconia), emax (lithium disilicate) and the suprinity (Zirconia reinforced lithium silicate). The factors that were tested were; the chipping factor, the edge strength parameter; the brittleness index; the fracture toughness, and the hardness. For chipping factor test; crowns were milled using CAD/CAM technology, and the marginal chips were examined using a digital optical microscope. For the edge strength parameter test; rectangular specimens were embedded in acrylic blocks, and a Rockwell indenter was attached to a universal testing machine, and the force needed to fracture the edge at a distance of 500 æm was recorded |