[Abrasion in modeling materials].
Ten frequently used hard plasters (Types 3 and 4 in accordance with DIN 13911) and 5 current modelling plastics have been investigated. Abrasion with testing forces of 1, 2 and 5 N were determined on samples 2 mm broad and about 12 mm long. The amount of abrasion could be calculated from the loss in weight. Only Kol-Dur and the plastics Diemet, Impredur and Alpha-Die are sufficiently reliable not to become damaged by abrasion on wax modelling (abrasion less than 5 micrometer). Hard plasters are not hard enough to resist abrasion. Taking into account the bending strength and modulus of elasticity, only Kol-Dur and Diemet can be recommended. Because of the improved dimensional stability of the hard plasters, Alca Dental Stone, Begolith, Duralit, Tewstone or Ferrodur can be recommended if the bending properties and a possible slight abrasion are taken into consideration. With the hard plasters, damage of more than 10 micrometer is easily possible.
D002133:Calcium Sulfate / Q000592:standards; D003760:Dental Impression Materials / Q000592:standards*; D006244:Hardness; D010969:Plastics / Q000592:standards
D003760:Dental Impression Materials; D010969:Plastics; D002133:Calcium Sulfate
Abrieb an Modellwerkstoffen.