The invention relates to three-dimensional dimensionally-stable moulded parts made of polymeric particles whose particles are connected firmly to each other, at least in part, at the contact sites of the particles, whereby the particles are preferably glued to each other, at least in part, at the contact sites. The pre-packaged moulded parts made of polymeric, powdery particles made of PMMA can take up acrylate or MMA into the porous three-dimensional structure and form a pasty or creamy dough that can be cast, pressed or injected and can be cured by common techniques after the forming. Also subject matters of the invention are the use of and a kit for producing said pasty dough. Said pre-packaged moulded parts are used in methods for producing prostheses, such as dental prostheses, bone cements, investment compounds, in particular of porous substrates, as investment compound in metallography.