Patent ID: 8865033

Claim:
A process for producing a dental appliance, the process comprising the steps of a) providing a mixture of a liquid, an inorganic binder precursor containing Si and O and a glass or glass ceramic powder, wherein the glass or glass ceramic powder is present in the mixture in an amount of about 60 wt.-% to about 85 wt.-%, b) casting the mixture into a mould, c) drying the cast mixture in the mould to obtain a machinable dental appliance, the inorganic binder precursor being able to undergo a sol/gel reaction, the mixture being obtained either by a process comprising the steps of: i) providing the liquid, ii) adjusting the liquid to a pH value suitable to start a condensation reaction, depending on the inorganic binder precursor used, iii) adding the inorganic binder precursor, iv) adding the glass or glass ceramic powder, wherein steps iii) and iv) can also be carried out in reverse order; or by a process comprising the steps of: i a) providing the liquid, ii a) adjusting the liquid to a pH value suitable to start the condensation reaction of a binder precursor (b), to be added later, iii a) adding a glass or glass ceramic powder and iv a) optionally adding an inorganic binder precursor (a), to obtain slurry I, i b) providing a liquid, ii b) adding a glass or glass ceramic powder and iii b) adding an inorganic binder precursor (b), to obtain slurry II iv) mixing of slurries I and II, wherein steps iii a) and iv a) or ii b) and iii b) can also be carried out in reverse order.