The effect of untreated UHMWPE beads on some properties of acrylic resin denture base material

Objectives: To evaluate the effect of surface untreated ultra high molecular weight polyethylene (UHMWPE) beads on a range of properties of the polymerised acrylic resin denture base material. Methods: UHMWPE in the form of surface untreated beads was added to acrylic resin denture base material in various percentages (2.5%, 5%, 7.5% and 10%) to form a composite material. The influence on doughing and manipulation times, transverse and impact strength and hardness characteristics were examined. Results: The results indicated that the manipulation and setting times gradually increased as the percentage of UHMWPE beads in the acrylic resin powder increased. By increasing the percentage of incorporated UHMWPE beads, there was a decrease in modulus of rupture and impact fracture resistance. There was also an effect on the hardness with an increasing percentage of beads lowering the hardness value, although this was not consistent. Conclusion: It was concluded that the use of untreated UHMWPE beads is of no significant benefit to the properties of acrylic resin. (C) 1997 Elsevier Science Ltd.