Bonding between soft liner (Molloplast B) and denture base resins (poly(methyl methacrylate)) is a significant problem. Surface treatment with some adhesives of denture base resins increase bonding between these two materials. The purpose of this study was to investigate the effect of thermocycling and of surface treatment with MMA monomer on the mechanical properties of the silicone-based soft liner. A silicone soft lining material (heat-polymerized silicone rubber) and heat-polymerized denture base resin, PMMA, were chosen for this investigation. Transient mechanical and dynamic mechanical properties changed with monomer treatment and/or thermocycling. (C) 2009 Elsevier Ltd. All rights reserved.