In-vitro antifungal efficacy of tissue conditioner-chitosan composites as potential treatment therapy for denture stomatitis

Tissue conditioners are commonly used to improve the adaptation of ill-fitting dentures. These materials are easily colonized by Candida albicans (C. albicans), resulting in "denture stomatitis". Chitosan and its derivative possess inherent antifungal activity. This study aims to formulate a chitosan-based tissue conditioner and assess its anti-fungal efficacy against C. albicans over time. A chitosan oligosaccharide (COS) was synthesized from commercially purchased chitosan and was characterized by Fourier Transform Infrared spectroscopy (FTIR) and X-ray diffraction analysis (XRD). The minimum inhibitory concentration (MIC) of COS and commercial chitosan against C. abicans was evaluated using broth micro-dilution assay (n = 3). Next, it was incorporated into tissue conditioners and two experimental groups i.e. tissue conditioner modified by chitosan (TC-CH) and tissue conditioner modified by COS (TC-COS) were prepared. The in-vitro antifungal activity of experimental group was compared with a control group (chitosan-free tissue conditioner) by counting numbers of colony forming units (CFUs) (n = 3). The antifungal potential of experimental formulations over time in a simulated oral environment was also evaluated using a spectrophotometry (n = 3). A potent in-vitro antifungal activity against C. albicans was observed. The minimum inhibitory concentration (MIC) of pure commercial chitosan and COS was 0.625 mg/ml and 0.3125 mg/ml respectively. Compared to the control group, experimental groups showed a reduction in number of CFUs of C. albicans density. Once immersed in saliva, the TC-CH retained its inhibitory effect for 24 h, while TC-COS exhibited improved inhibition until the third day, beyond which a gradual reduction in the inhibitory effect was observed. Experimental formulations showed a reduction in C. albicans density compared to the control group. Thus, a novel combination of chitosan and tissue conditioners is a promising alternative for prevention and treatment of denture stomatitis.