Background: Because of the viscoelastic properties of soft liners, these materials will act as a cushion between the denture and the edentulous ridge to lower and redistribute the occlusal forces over the denture bearing area . One of the major problems associated with the soft liner using is the increased risk of invasion of Candida organisms on the soft lined dentures intaglio surface .The study was aimed to investigate antifungal effect of incorporation of Chitosan nano particles into heat cured acrylic based soft lining material .

Methods: Thirty samples were prepared and divided into three groups (control group, 1.5wt%, 2wt% experimental group), ten samples for each group, The sterile soft lining samples were deposited in sterilized tubes containing Sabouraud dextrose broth in which a small portion of the isolated yeast were suspended and incubated for 1 hr. at room temperature. After that , the specimens were removed , rinsed with Phosphate buffered saline , dried then fixed by methanol , stained with crystal violet and examined under inverted light microscope.

Results: The result of adherence test showed a highly significant decrease in the number of Candida cells adhered to soft liner after incorporating 1.5wt%, 2wt% chitosan compared to samples of control group.

Conclusion: Chitosan can be regarded as a strong antifungal material and incorporating the chitosan into soft liner can succeed in producing soft lining material with antifungal activity against Candida micro organsims.

Keywords: Chitosan, Nano-Particles, Denture Lining Material, Candida Albicans Adherence.