High-strength dental gypsum prepared by cold isostatic pressing.
Powder of a dental plaster (Moldabaster, Bayer) was compacted by cold isostatic pressing (CIP) at 300 MPa for 10 min and immersed in water for 1 h. The compressive strength of the CIP-processed material was compared with that of conventionally processed material. The green block of plaster before water immersion was carvable with a green density and green strength of 50% and 5 MPa, respectively. The compressive strength of the CIP-processed gypsum after 24 h was three times higher than that of conventionally processed, 103 compared with 29 MPa, and the microhardness (Vickers hardness number, VHN) of CIP-processed materials was 40 compared with 12 VHN. An increase of density was also recorded. It seems that the CIP process produced a dense and pore-free gypsum with a composite-like structure. The high-strength gypsum processed by CIP may extend the applications of this material in the medical field as implant materials.
Li
J
J
Center For Dental Technology and Biomaterials, Karolinska Institute, Huddinge, Sweden.
Alatli-Kut
I
I
Hermansson
L
L
D001696:Biomechanical Phenomena; D002133:Calcium Sulfate / Q000302:isolation & purification*; D003080:Cold Temperature; D003764:Dental Materials / Q000302:isolation & purification*; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D011312:Pressure
D003764:Dental Materials; D002133:Calcium Sulfate