## 4 Discussion  
The aim of this study was to evaluate the efficacy of a non-thermal O\({}_{2}\) plasma (O\({}_{2}\) NTP) as an alternative method for the disinfection or sterilization of denture base resin. The null hypotheses were rejected since O\({}_{2}\) NTP reduced _C. albicans_ viability and slightly altered the color stability of the resin for denture base. DS is a common disease in elderly and immuno-depressed people, and mainly occurs under imbalance of the oral microbiota entailing local factors such as wearing dentures [2; 3; 4; 5; 6; 12]. The focus in the treatment of denture stomatitis is to eliminate the source of pathogens which contaminate dentures [3; 8; 11; 12]. However, it is essential to obtain a safe disinfection or sterilization protocol without any harmful effect on the physical and mechanical properties of resins for denture base [16]. Nowadays, there are different mechanical or chemical techniques to decontaminate dentures [12; 16; 49; 50]. Alkaline peroxide is the most common molecule among chemical cleansers [22]. However, [PERSON] et al. [51] highlighted that the 15-min treatment recommended in some manufacturer's instructions (Fittydent, Polident, Corega) is not sufficient for denture in vivo decontamination. They noted that only Fittydent brand allows an antifungal activity after a 60-min immersion. Moreover, these cleansers must be used correctly due to their possible toxicity on oral and oropharyngeal tissues as the degradation of the different agents leads to hydrogen peroxide [16; 22]. Many other molecules or cleansers have been tested or recommended in guidelines, such as chlorhexidine, chlorine dioxide, sodium hypochloride, and plant extracts [17; 50; 51]. However, if some agents reduce _C. albicans_ viability, other molecules are not efficient [22]. Therefore, the development of new techniques could be an alternative to those chemical antiseptics. Hence, plasma processes have been tested for one decade on resin for denture base. Some studies dealt with the effect of atmospheric plasma on _C. albicans_ biofilms developed on PMMA [52; 53]. They evaluated atmospheric plasma using argon (Ar) or Ar/O\({}_{2}\) mixture as working gas. [PERSON] et al. [52] obtained a 4.12-log reduction of _C. albicans_ viability over 10 min using a dielectric barrier discharge whereas [PERSON] et al. [53] reached a 6-log reduction over 8 min using a plasma jet. These results vary due to the different plasma sources and the different methodologies used for evaluation. In previous studies [37; 38; 46], we have developed a low-pressure NTP process that treats prepackaged items. This process has already proved efficacy against _S. aureus, P. aeruginosa_ and _B. subtilis_ spores. In this study, this approach was completed by investigating _C. albicans_ inactivation using O\({}_{2}\) as the working gas. We demonstrated that low pressure without plasma generated only a small decrease of _C. albicans_ viability (glass: 3.12-log reduction, resin: 1.78-log reduction). Thus, the direct effect of low pressure could not solely be responsible for the _C. albicans_ inactivation. Moreover, when low pressure was applied without plasma, the pressure in the vacuum chamber decreased up to