## 1 Introduction  
In this era, where the Corona Virus Disease-2019 (COVID-19) pandemic has become a significant global public health problem [1], and the rise of antibiotic resistance has resulted in an increase in untreatable infections [2, 3], prevention of diseases has become pivotal and, in most cases, more cost-effective than cure [4]. The recent pandemic has further brought to light the high risk of cross-transmission of pathogens, including the Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) responsible for COVID-19 [5], in dental practices for both patients and dental healthcare professionals (DHCPs) due to the working conditions in close and prolonged contact with patients and the performing of aerosol-generating dental procedures (AGDPs) [6, 7, 8]. In 2020, the New York Times stated that dentists are at the top of the ranking among healthcare professionals that are most at risk of cross-infections [9]. Airborne transmission from an infected individual in close contact with another is the main route of transmission for respiratory pathogens [10]. However, the indirect transmission by first touching a contaminated surface and then touching the eyes, nose, and/or mouth, is no less significant [11], especially in relatively closed environments such as dental practices [12; 13]. By definition, aerosols are composed of droplets with a size \(\leq\) 5 \(\upmu\)m in diameter, which can remain suspended in the air for hours, moved by air currents, until they deposit on surfaces [10]. The survival time of pathogens on the surfaces depends on several factors, including the microbial load, the material of the considered surface, and the ambient temperature and humidity [10; 14]. For instance, during the recent pandemic, it has been demonstrated that SARS-CoV-2 can remain viable in respiratory droplets for up to 3 h [8; 13], while on stainless steel and plastic surfaces, it can survive up to 72 h, with an average half-life of about 5.6 and 6.8 h, respectively [15; 16]. The virus seems more stable on smooth surfaces and at a room temperature of 20-22 \({}^{\circ}\)C [17]. To reduce the risk of cross-infections in dental practices, DHCPs have to adopt protective measures and protocols, which have been further reinforced with new recommendations during the COVID-19 pandemic [8; 18; 19; 20]. Assuming that proper hand washing is essential to prevent indirect contagion, accurate disinfection of work environments is equally important to reduce the risk of cross-infections, preventing the spread of pathogens, especially after performing AGCDPs [12; 18; 19]. Among conventional disinfection methods, liquid chemical products such as sodium hypochlorite, hydrogen peroxide and ethanol are the most commonly used. The effectiveness of chemicals is closely related to the type of the product used and to its application procedure [21]; these products may also require long contact times to be effective (up to 5-15 min) and may release irritating or toxic disinfection-by-residues requiring an extra ventilation of the disinfected environments [21; 22; 23]. A non-toxic and environmentally friendly alternative to chemical disinfection is represented by overheated dry-saturated steam disinfection, which is part of the so-called \"No-Touch\" Disinfection (NTD) systems, also including ozone, air ionization and Ultraviolet (UV) radiation [21]. The literature describes overheated dry-saturated steam as effective in inactivating heat-sensitive bacteria, fungi and viruses, thus reducing the microbial contamination of the disinfected surfaces [22; 23; 24; 25; 26; 27; 28]. For instance, [PERSON], 2009, states that 5-s steam disinfection was able to completely inactive Escherichia coli, Enterococcus faecalis, methicillin-resistant Staphylococcus aureus (MRSA), Candida albicans and the endospores of Clostridium difficile on the treated surfaces [24] and, according to [PERSON] et al., 2012, already within 3 s of steam use, the 99.95% of E. coli, Pseudomonas aeruginosa and S. aureus present on surfaces, were killed [22].