In addition to the transformation of soft palate substance defect in a functional moment, considering conformity, blockade and speech etc., the authors have thought it preferable that the prosthesis be fabricated with elastic material. For this reason, a silicone rubber material (MDX-4-4210, Dow Corning Corporation) has been clinically applied to soft palate substance defect, and examined concerning physical properties. To obtain the physical properties of this material, a stress relaxation was recorded after the specimens were subjected to strain. Taking into account the stress relaxation curve from the results in this study, an analysis of a mechanical three element model has been put into practice. According to the results of the analysis of the mechanical model, the effects of time, curing condition and water temperature on physical properties have been compared.
It was found that this material is extremely stable, and not influenced by time, curing condition or water temperature. Also this material has approximated the action as an elastic material in an occlusal moment with negligible viscosity.
Finally the authors report that the prognosis of two clinical applications has been favorable.
