Craig R. Means, DDS, MSc Nelson W. Rupp, DDS, MS George C. Paffenbarger, DDS, Washington, DC This paper reports clin ical observations made on 14 patients who wore 23 dentures. The dentures were lined with either Coe Super Soft or Silastic 616 re silient liners. Observations that were made during the 21-month study led to the following conclu sions. ■ Both materials are safe to use against oral t is sues. ■ Because deterioration and loss of resilience reduce their effectiveness in a short time, dentures lined with these materials should be observed every three months. ■ The border junction between the resilient lin er and the denture base should be a butt joint. A thin tapered junction is unsatisfactory. The finish line should be well away from the borders of the flanges. ■ These resilient liners should be considered as temporary expedients, to be used only in selected cases that require a protective resilient surface on the tissue-bearing side of the denture base. A denture with a resilient liner should be su ffi c iently th ick in cross section to resist fracture. Thinning the denture to accommodate a resilient liner may lead to fracture in sen/ice.