Original article Comparative evaluation of antifungal action of tea tree oil, chlorhexidine gluconate and fluconazole on heat polymerized acrylic denture base resin – an in vitro study Sameen Dalwai 1 , Shobha J. Rodrigues 1 , Shrikala Baliga 2 , Vidya K. Shenoy 3 , Thilak B. Shetty 1 , Umesh Y. Pai 1 and Sharon Saldanha 1 1 Department of Prosthodontics, Manipal College of Dental Sciences, Mangalore, India; 2 Department of Microbiology, Kasturba Medical College, Mangalore, India; 3 Department Of Prosthodontics, A J Institute of Dental Sciences, Mangalore, India Gerodontology 2014; doi: 10.1111/ger.12176 Comparative evaluation of antifungal action of tea tree oil, chlorhexidine gluconate and fluconazole on heat polymerized acrylic denture base resin – an in vitro study Objective: Candida albicans-associated denture stomatitis is the most common type of denture stomatitis seen in denture wearers. This study evaluates and compares the antifungal action of fluconazole, chlorh- exidine gluconate and tea tree oil on heat-polymerised denture base resin, which has been previously contaminated with C. albicans grown in BHI broth. Material and Methods: Seventy-five specimens were immersed in BHI broth previously inoculated with C. albicans and stored for 3 h at 37°C. They were divided into five groups (n = 15): G1: 2% chlorh- exidine solution; G2: 100% pure pharmaceutical grade tea tree oil; G3: 65 lg/ml fluconazole solution; C1: specimens not disinfected; C2: specimens not contaminated with Candida. Each specimen was then transferred to individual tubes containing BHI broth and incubated for 24 h. Culture media turbidity was evaluated for absorbance over a period of 14 days using a microplate reader. It was observed that the lower the absorbance, the stronger the antimicrobial action. Statistical analysis was performed (two- way ANOVA and Bonferroni test, p < 0.001). Results: Chlorhexidine and tea tree oil inhibited Candida up to the 14th day, whereas antifungal effect of fluconazole was not significant after the 7th day. Conclusion: Tea tree oil and chlorhexidine gluconate are more effective than fluconazole in inhibiting C. albicans growth on heat-polymerised acrylic resin. Keywords: denture stomatitis, denture cleansers, Tea tree oil, Melaleuca alternifolia. Accepted 18 November 2014 Introduction Denture stomatitis, also known as chronic atro- phic candidiasis or denture sore mouth, is an inflammation of the oral cavity prevalent in 11– 67% of geriatric complete denture wearers. 1 It is associated with the formation of biofilms on bioprosthetic surfaces. 2 Candida albicans is a normal commensal of the oral cavity, but it becomes pathogenic due to local or systemic predisposition caused by chronic irri- tation or immune deficiency. Several investigators have demonstrated that C. albicans colonies are more frequently isolated from the tissue-fitting surfaces of acrylic resin dentures than from the corresponding mucosa. 3,4 Hence, the denture may function as a reservoir of infection, and the sur- face irregularities on the denture increase the likelihood of microorganisms remaining on the surface after the prosthesis has been cleaned 5 . Many studies have evaluated the effect of den- ture cleansers and disinfectant solutions on initial Candida adherence to denture base materials. However, little attention has been paid to the effect of these denture cleansing agents on Can- dida-associated mature biofilm, the cells of which are known to be more resistant to antimicrobial compounds and chemical cleansing. 6 Many herbal formulations, such as Melaleuca alternifolia oil, have been established as potent © 2014 John Wiley & Sons A/S and The Gerodontology Association. Published by John Wiley & Sons Ltd 1