Aim : This study evaluated the tensile strength of polymer-based and silicone-based soft denture liners, with and without 2% titanium dioxide (TiO₂) nanoparticles, under thermocycling conditions.

Subjects and methods: Specimens were fabricated using heat-cured acrylic resin discs coated with soft liners and subjected to thermocycling (3000 cycles, 5°C–55°C). Tensile strength was assessed using an Instron testing machine.

Results: they showed that polymer-based liners had significantly higher tensile strength than silicone-based liners (p < 0.001). Thermocycling minimally affected polymerbased liners but reduced the strength of silicone-based liners. The addition of TiO₂ nanoparticles did not significantly alter the tensile strength of either material (p > 0.05).

Conclusions: Polymer-based liners demonstrated superior mechanical performance, indicating their potential for clinical applications. Further research is needed to optimize nanoparticle incorporation and evaluate long-term clinical outcomes.