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The purpose of this study was to investigate some clinically relevant properties of Clearfit LC, a newly developed polyisoprene-based light-curing lining material. Its properties were compared with those of other four commercial products.Five soft lining materials, Clearfit LC, two plasticised acrylics (Super-soft, Soften) and two silicones (Molloplast B, Sofreliner) were used to determine water sorption, solubility, staining resistance, Shore A hardness and shear bond strength to denture base. Five specimens for each test were fabricated. The results of each test among the five materials were compared by one-way ANOVA and Scheffe's post-hoc test at alpha=0.05.One-way ANOVA of each test showed that the differences among five materials were significant (P0.05). Clearfit LC showed the intermediate water sorption and solubility (10.07; 1.72 microg/mm(3)). It also showed the lowest color change in beta-carotene/olive oil solution and instant coffee solution (DeltaE=1.19, 5.48, respectively). The shear bond strength of Clearfit LC was 1.56MPa, and no adhesive failure was found. Its Shore A hardness value (56.2) was located between two acrylics and silicones. It was also found that the softer materials tend to failure cohesively.The polyisoprene-based lining material showed low water sorption and solubility, moderate softness, high staining resistance and satisfactory shear bond strength to denture base resin. It also provides clinicians sufficient working time due to its light-curing property. It would be an attractive alternative as a relining material.

Objectives: The purpose of the study was to examine and describe the deformation behaviour of five denture soft lining materials under dynamic cyclic loading over a range of applied forces using apparatus designed to simulate masticatory performance. Methods: Five lining materials were tested over 5-min periods using an Instron tensile testing machine that was modified to measure load and strain semi-continuously during cyclic loading. Results: Strain energy and strain energy densities and moduli values for each material were calculated. The strain energy absorbed at separate times during the cycling period demonstrated the elastic behaviour of the materials over the 5-min simulated chewing cycle. Conclusions: All materials demonstrated elastic but not perfectly linearly elastic behaviour over the chosen loading and cycling frequency. Molloplast B absorbed most energy at the lower testing loads and Novus absorbed most energy at the higher loads.