Impression materials for recording the denture bearing mucosa.

To accurately record the denture bearing mucosa at rest or with the least possible tissue movement, the following suggestions should be considered: The denture bearing mucosa should be healthy and firm. Impression materials used should be of low viscosity. Materials which rapidly increase in viscosity after mixing should be placed in the mouth as soon as possible without compromising acceptable clinical procedures. The zinc oxide-eugenol materials have an advantage of a much longer working time. Materials with low contact angles with water may have flow characteristics that are more favorable for making impressions of the denture bearing mucosa. The pressure used to seat and hold an impression of the denture bearing mucosa should be kept at the minimum necessary to achieve adequate flow for that impression material. From this discussion, it is evident that no single impression material is ideally suited for making edentulous impressions. Perhaps in the future the dental manufacturers will consider developing and marketing products with the specific performance characteristics that have been outlined. Until that time, clinicians should be aware of the characteristics of the material they are using and modify their techniques accordingly.