Frequently asked question.

Q: Is the fit of crowns and bridges based on zirconia copings…

  • A: Yes, the marginal fit of crowns and bridges fabricated from zirconia copings can be as good or better than PFM crowns and bridges.

Q: Is the fit of a zirconia coping important since the zircon…

  • The thicker the cement the weaker the all-ceramic restoration. Cements are not as rigid as zirconia ceramic, so a thicker cement layer will cause more flexural deformation of a ceramic core, increasing the potential for fracture.

Q: Does silane treatment improve the bond strength of a resin…

  • A: No, but the use of Rocatec/Cojet (3M ESPE) does. Silica particles are embedded into the surface of zirconia and then silanated. This treatment can increase the bond strength of a resin cement to a zirconia coping.

Q: Is it ok to grind on a zirconia coping without water spray…

  • A: Water spray is necessary when grinding on a zirconia ceramic coping. The white light or hot spot you see between a diamond and a zirconia ceramic has been measured at 1500 C. If the temperature of zirconia ceramic rises above 1000 C, a phase change can

Q: Is preparation design of a zirconia coping important since…

  • A: Preparation design of the zirconia coping is very important. The thickness of unsupported porcelain should not exceed 2 mm. The zirconia coping should be as thick as needed to avoid unsupported porcelain.

Q: How much strength do you really need with zirconia at the …

  • The fractures are most likely caused by insufficient support of the overlay porcelain in the marginal ridge area. Porcelain is much stronger in compression that in is in tension and shear. If the marginal ridge area isn’t built out with sufficient zirconi

Q: What is the best substructure design to provide sufficient…

  • A: The overlay porcelain should not be thicker than 1.5 to 2 mm depending on the location and should be adequately supported by the zirconia coping.

Q: What type of porcelain is used for the overlay materials f…

  • A: There are a number of zirconia-optimized porcelain systems available. Most zirconia ceramics have a coefficient of thermal expansion (CTE) of about 10. Make sure the overlay porcelain has a CTE close to 10. Do not use porcelain intended for PFM.

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White Fused Alumina for abrasive is grinding tool machining method is very important class of methods, but also precision machining and ultra precision machining .

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