Background: Denture stomatitis (DS) is chronic inflammation of the mucous membrane supporting the removable prosthesis. Polyene antifungal drugs such as Nystatin have been used to treat DS. Side effects, high prices, and complicated production processes of chemical drugs have led to the use of medicinal plants. According to the evidence of antifungal effects of sumac (Rhus coriaria), the present study aimed to assess the impact of mouthwash containing sumac extract on patients with DS.

Material and Methods: This study was a single-blinded clinical trial. The statistical population included healthy individuals with DS (type II) using complete maxillary dentures referred to the Dental Clinic of Mazandaran University of Medical Sciences. The sample size was n = 22 (n = 11 in the nystatin group and n = 11 in the intervention group), and the samples were selected randomly. Nystatin (100,000 U/mL) and sumac (2%) mouthwashes were used three times a day for 2 weeks by patients, and erythematous lesions were examined and photographed every week. At the beginning and end of the study, smear and culture (Sabouraud’s dextrose agar) were prepared from the infected area of the palate. Then, the colonies were counted to evaluate the cultured samples and their yeast growth rate and the cultured species on CHROMagar Candida medium, were determined based on colorimetry.

Results: In this study, patients in the two groups were not significantly different regarding demographic information. The size of DS lesions and the colony count of Candida fungus in each session of the visit, compared to pre-treatment, were reduced in both groups (p <0.001). The reduction in the nystatin group showed no significant difference compared to sumac mouthwash (length p <0.001), (width p <0.0220) and (colony count p <0.0371). Also, the culture results on CHROMagar Candida medium showed that the predominant Candida species of both groups were Candida albicans, and no statistically significant difference was between the two groups in terms of distribution of Candida fungal species (p = 0.141).

Conclusions: Both Sumac extract and Nystatin were effective in preventing denture stomatitis complications. Considering the side effects of Nystatin, a mouthwash containing Sumac extract can be used as an adjunct to nystatin to reduce side effects from long-term use, especially in patients sensitive to nystatin.