[Studies on the flow properties of autopolymerizing hard-setting resins used as direct relining materials for denture...

Autopolymerizing hard-setting direct relining resin is currently being used in dentistry to attain denture bases that conform to the supporting tissues with a high degree of accuracy. The purpose of this study is to investigate the flow of six commercial hard-setting direct relining resins (Denture Liner, Kooliner, New Truliner, Rebaron, Swift, Tokuso Rebase) and several types of impression materials (zinc oxide-eugenol, polysulfide rubber, silicone rubber) using the parallel plate viscometer. The viscometer is used to measure the spread radius of samples (a volume of 0.5 cm3) between two parallel flat plates when a load of 750-gram weight is applied at 1, 10, 60, 100 seconds after loading has begun. In this experiment, the load was applied at 120, 150, 180, 210, 240, 300 seconds after mixing had begun. All the samples were mixed according to the manufacturer's recommendations. The findings were as follows; 1. The flow of the six commercial hard-setting direct relining resins could be compared with one another by the spread radius at 1 second after loading (r1) with no relation to time lapse after initiation of the mix. 2. Denture Liner, Kooliner, Rebaron and Swift had the same flow characteristic when r1 was the same. 3. Polysulfide rubber impression materials had similar flow characteristic to hard-setting direct relining resins.