Paper Title
Accelerated Release Behavior of Ions Loaded in Diatomite by Ultrasound

Abstract
In dental treatment, impressions are taken to reproduce the morphology of the mouth. Polysaccharide gel of sodium alginate is widely used as a dental impression material. A powder of sodium alginate containing calcium sulphate is mixed with water and poured into impression trays, which are then used to make dental moulds. Diatomaceous earth is added to optimize the mechanical strength of the gel after the gelation. Usually, the mixing ratio is determined so that the past of sodium alginate forms a gel in approximately three minutes. In general, the gelation of sodium alginate by divalent ions is very fast. This feature is suitable for the preparation of gel beads, however it needs to be devised for moulding processes, such as impression materials for dental use. In fact, commercially available impression materials contain a chemical agent for slow reaction. Even with a retardant, the gelation time cannot be freely controlled. The aim of this study is to develop a new impression material that can be controlled the gelation time. Diatomaceous earth was pre-loaded within divalent ions and the amount of divalent ions released was controlled by ultrasound irradiation. The effect of ultrasound irradiation on the gelation time has been studied.