## 1 Introduction  
The human oral microbiota includes hundreds of microorganisms that contribute to a well-balanced buccal environment [1]. _Candida albicans_ figures among the most common yeasts identified in approximately 50% of healthy adults [2]. This microorganism is an opportunistic pathogen that can lead to different forms of oral fungal infections especially denture stomatitis (DS) [3,4]. DS is a common disorder that can affect a variable number of denture wearers, ranging from 11% up to 75% of them [5,6]. The characteristics of this disease are essentially an inflammatory process and erythema of the palatal oral mucosa associated with Candida species, especially _C. albicans_, which adhere and form biofilms on the oral mucosa and denture surfaces [7,8]. Its common symptoms are \"bleeding, swelling, burning or other painful sensations, halitosis, unpleasant taste and dryness in the mouth\" [9]. Moreover, this disorder could potentially enhance the risk of systemic infections, particularly in elderly subjects [10,11]. This disease involves different etiologies such as autoimmune disorders, systemic diseases, salivary dysfunctions, trauma, poor denture hygiene and wearing denture overnight [3,7,8]. The DS therapeutic strategies to overcome this fungal infection must therefore take into consideration both patients and dentures. Thus, a topical and/or systemic antifungal treatment must be administered to patients who must also improve their oral and dental hygiene [8,11,12]. However, an increase in antifungal-resistant Candida strains has been reported in recent years [12, 13, 14]. This can lead to poorer clinical outcomes for patients and create a higher risk of systemic infections [15]. Consequently, regular maintenance of dentures is essential. Nowadays, there are many guidelines all over the world which usually recommend to daily brush dentures and to remove them at night [16,17]. In addition, many disinfectants are proposed to clean dentures regularly in order to reduce or prevent the formation of _Candida_ biofilm on them. These disinfectant solutions include a wide variety of chemicals such as sodium hypochlorite, alkaline peroxides, chlorhexiidine, plant extracts, etc. [18, 19, 20, 21, 22] However, prolonged use of these molecules is necessary to avoid any recurrence of DS [6,12]. However, numerous studies reveal that these disinfection methods can alter the properties of dentures base resins such as flexural strength [19,23,24], hardness [20,25,26], surface roughness [25, 26, 27, 28, 29, 30] and especially the color stability [18,19,21,24,25,27,29,31,32]. Indeed, the main color change results in resin bleaching [16,19,21,24,25,27,29,30,31]. Those adverse effects can have consequences on denture wearers' aesthetics and comfort, and therefore on their social life. To overcome those issues, many alternative disinfection methods have been proposed such as microwaves [33,34] or ultraviolet (UV) radiation [35]. Cold plasma, or non-thermal process, has been developed as a new disinfection method in the medical field for the last decade. Plasma is an ionized gas consisting of ions, electrons, UVs, photons, neutral species and reactive oxygen and nitrogen species (RONS) that have shown their efficacy to inactivate various micro-organisms such as bacteria, spores, yeasts or viruses [36, 37, 38, 39, 40]. Many techniques using non-thermal plasma [41, 42, 43, 44] differ from one another in terms of operating pressure (low or atmospheric pressure), and operating conditions (electrical current, gas nature and flow rate). A few years ago, a low-pressure plasma process was developed, which could preserve the sterile state of items after the end of treatment [37,38]. In dentistry, this process could be used by dentists or by care home staff for denture maintenance. The aim of this study was to assess whether a non-thermal O\({}_{2}\) plasma process could inactivate a _C. albicans_ strain on a heat-cured polymethyl methacrylate (PMMA) resin for denture base without significantly modifying its color.