Process for producing a dental appliance

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.