Method: A total samples of (104) were prepared from acrylic based heat cured denture soft lining material (Vertex), which divided into two main groups (short and long curing cycle according to ADA) respectively, each main group was subdivided into four groups according to oil addition [Sesame, Thyme, mixed (Sesame and Thyme), and control group]. Volumetric changes, color stability, and antifungal tests were done on each of two main groups (short and long cycle). The tests were done after two periods of immersion in distilled water (two and thirty days), except for antifungal tests were done after (two, seven and thirty) days of immersion in distilled water.
Result: The results of this study showed that plant oil extract of (Sesame and Thyme) at 5% per volume addition into monomer resulted in a shrinkage of sample volume ranged (0.32% - 0.4%), which was accepted by ADA specification for volumetric changes. There were an in vitro accepted color changes after addition. While, after thirty days period resulted in acceptable in vivo color changes. Plant fixed oil addition resulted in a modified denture soft lining material (Vertex) with antifungal activity after curing especially for Thyme oil group.
Conclusion: It is concluded that plant fixed oil extracts addition added an antifungal potentials after addition. Modified denture soft lining material with Thyme or mixed oil addition could be recommend for treatment of denture stomatitis.