Influence of dietary simulating solvents on the viscoelasticity of temporary soft lining materials

Statement of problem. Clinical changes in the viscoelasticity of temporary soft lining materials are characterized by a more rapid and increased reduc tion in compliance than is seen after in vitro immersion. A possible explan ation for these differences is a solvent effect, acting clinically to encou rage the loss of ethanol and plasticizer. Dietary solvents have been sugges ted as likely agents. Purpose. This study examined the effect of immersion in dietary simulating solvents on the viscoelasticity of temporary soft lining materials, with a view to formulating more clinically relevant immersion regimes used in the evaluation of these materials. Material and methods. Four temporary soft lining materials were immersed in distilled water and solutions chosen to simulate dietary solvents. Changes in viscoelasticity over time were recorded with a penetrometer, modified t o record creep strain and strain during recovery. Results. All immersion solutions caused a significant reduction in complian ce values of each material over time (P<.05). However, only heptane and cor n oil immersants produced the rapid and increased reduction in compliance t hat is evident clinically. Changes in elastic recovery mere less pronounced . Conclusion. Results of this study offer support to a dietary source of solv ent acting to effect clinical changes in the viscoelasticity of temporary s oft lining materials.