Method and apparatus for producing a shaped article by sonoerosion

A method of manufacturing a superstructure of an artificial tooth which has in a part of its surface a locking portion for positive engagement with a counter-locking portion of a pre-fabricated shaft part of the tooth to be implanted in a jaw, the remaining surface of said superstructure being individually shaped, the method comprising the steps of:

• (a) implanting said shaft part into the jaw,
• (b) taking an impression of the portion of the jaw including and surrounding the implanted shaft part,
• (c) forming a positive model of the superstructure of the artificial tooth to be produced,
• (d) preparing first and second individually formed sonotrodes from opposite sides of said positive model,
• (e) preparing a ceramic blank and forming a bore therein by using a pin-shaped sonotrode,
• (f) forming said locking portion in said ceramic blank by using a standardized sonotrode, said standardized sonotrode having a centering pin engaging the bore formed in step (e),
• (g) aligning said first sonotrode formed in step (d) with the locking portion formed in said ceramic blank and working part of said remaining surface of the blank surrounding said locking portion with said first sonotrode, and
• (h) working the opposite side of said blank with said second sonotrode formed in step (d).