In Vivo and In Vitro evaluation of the efficacy of a peracetic acid-based disinfectant for decontamination of acrylic resins

Abstract

The purpose of this study was to assess the antimicrobial efficacy of a peracetic acid-based disinfectant for decontamination of heatpolymerized, chemically activated and microwave-polymerized acrylic resins. Resin plates were contaminated in vivo upon intraoral use by 10 volunteers for 7 nights and slabs were contaminated in vitro by contact with Bacillus subtilis and Bacillus stearothermophilus. The contaminated acrylic resin specimens were immersed in a 0.2% peracetic acid-based disinfectant (Sterilife ® ; Lifemed) for 5 min or 10 min and placed in a BHI culture medium. After incubation at 37°C for 48 h, bacterial growth was assessed by analyzing turbidity of the medium. For all types of acrylic resin, no turbidity of the medium was observed for any of the resin specimens immersed in the peracetic acid-based disinfectant for either 5 or 10 min. On the other hand, the media with specimens that were not immersed in the disinfectant (control) showed turbidity in 100% of the cases, indicating the presence of microorganisms in both tested conditions. In conclusion, immersion for at least 5 min in a 0.2% peracetic acid-based disinfectant promoted high-level disinfection of heatpolymerized, chemically activated and microwave-polymerized acrylic resins contaminated with either human saliva or Bacillus subtilis or Bacillus stearothermophilus.

Influence of peracetic acid at acrylic resin properties

“…However there was no statistically significant difference regarding the microhardness between test and control groups. It demonstrates that, although the peracetic acid has unstable peroxide in its composition that could act on the residual monomers of the polymerized resins and change their degree of polymerization, generating interference its hardness, this did not happen (1,8,15,16).…”

“…Peracetic acid does not offer occupational hazards and is also less irritating than glutaraldehyde, furthermore has the advantages of being efficient, of acting fast and of being highly compatible (1). Therefore, the decomposition of peracetic acid into other components such as water, hydrogen peroxide, oxygen and acetic acid, shows an important differential to compared it with other methods of chemical disinfection, such as biodegradability (20).…”

“…However, the porous characteristics of acrylic resin in contact with oral environment may lead to colonization of microorganisms on device surface. The microorganism colonization could works as a cross infection vehicle to patients and professionals (1). A great variety of microorganisms was found at acrylic devices surfaces, such as Streptococcus sp, Staphylococcus sp, Escherichia coli, Pseudomonas sp, Klebriella pneumoniae, Candida sp, SIDA and Hepatitis B viruses (2)(3)(4)(5)(6).…”

“…Due to the acrylic resin low thermal properties, disinfection procedure using high temperatures are avoided and many chemical disinfection agents have been suggested to be used on removable acrylic devices disinfection (1,7). Hypochlorite 1% has been related as an effective solution to eliminate microorganisms in only 10 minutes of immersion.…”

“…PA presents fungicidal properties, sporicide, bactericidal and virucidal action and it presents no skin sensitizing reactions (9). Furthermore, PA presents an easily discard after use due to its decomposition in acetic acid and water (1). In dentistry, acrylic resins specimens were sterilized after a 5 minutes immersion in PA solution (10).…”