If you need to grind the frameworks, it is very important not to over heat them:

We recommend using a hydraulic cooling turbine, with diamon drill dedicating for this use.

If you use a standard drill, your chances to modify the structure of the zirconia on the surface are higher. Make sure not to over heat the frameworks changing the constantly the milling area. Once again use diamond drill dedicate to this use.

Use fine damons drill

Before you start the cosmetic:

Clean the work with steam to get ride of any trace due to fingers contact, or milling dust.

It is not recommend to sand blast the framework surface, recent studies shows that it doesn’t improve zirconia/porcelain jonction, but if you feel the need use alumina oxide 50µ with a low pressure(max. 0,5 bar)

To increase the sealing you can do a light sand blast in the intrados with alumina oxide 50µ maximum (max. 0,5bar)