## 1 Introduction  
The aim was to evaluate the disinfection of _E. coli_, _S. aureus_ and _S. mutans_ cultured on Polymethyl Metachymetla (PMMA) resin polymer using microwave disinfection and sodium perborate (DC). Biofilms of _E. coli_, _S. aureus_ and _S. mutans_ were cultured on the PMMA denture base for 24, 36, 48 and 96 h. Specimens were subjected to three disinfection protocols, including microwave disinfection in distilled water (MW-DW), sodium perborate (denture cleaning tablet) with distilled water (DC-DW) and a combination of MW-DC-DW for 1 to 5 min. Colony-forming units among the study groups were analyzed using Kruskal-Wallis and Mann-Whitney tests. For _E. coli_ and _S. aureus_ cultured on PMMA, the MW-DC-DW group displayed complete disinfection at 2 min of exposure. However, for both bacteria, the MW-DW disinfection group showed zero CFU at 3 min. DC disinfection for _E. coli_ and _S. aureus_ displayed zero CFU at 5 min of exposure (\(p\leq 0.05\)). For _S. mutans_, MW-DC-DW and MW-DW displayed zero CFU count at 1 min and 2 min, respectively. In DC-treated samples, CFU were significantly zero at 4 min when compared with the control at each growth time. A combination of MW irradiation with DC (sodium perborate) showed higher disinfection percentage of bacterial species on PMMA polymer denture bases compared to MW and DC alone. PMMA disinfection using DC displayed a lower antimicrobial disinfection percentage than the combined use of MW and DC as well as MW alone at 1 min or 2 min disinfection for _E. coli_, _S. aureus_ and _S. mutans_. polymers; polymethyl methacrylate; bacteria; disinfection; oral health  
## 1 Introduction  
The artificial replacement of completely missing teeth with restoration of form, function and esthetics is critical to improving quality of life among defendulous patients [1]. A majority of defendulous patients experience psychosocial problems due to criticism, embarrassment and low confidence levels. For decades, different techniques and materials, i.e., wood, ivory and metals, have been employed for artificial denture fabrication [2]. Polymethyl methacrylate (PMMA) polymer denture resin material has been the material of choice for denture fabrication for the last 50 years, and has gained widespread acceptance due to its simplified processing and equipment, functional longevity, ease of maintenance, cost-effectiveness and esthetics [3]. The longer life expectancy of the elderly population leads to a higher number of individuals needing an artificial removable prosthesis [4]. defendulous patients may lack manual dexterity and be unable to remove denture plaque. Therefore, PMMA denture patients are more susceptible to mucosal infections from bacterial and fungal species. In addition to various bacteria, _Candida albicans_ (fungi) are most commonly associated with denture-related oral infections [5]. In order to overcome denture-related infections, different denture cleansers are used to effectively remove stains and food debris from the denture bases [6]. At present, different PMMA denture cleaning and disinfection techniques include mechanical, chemical and physical methods. Mechanical methods used for denture cleaning include the use of a toothbrush with water [7]. In their study, [PERSON] et al. [8] revealed that 60-90% of denture patients practice mechanical cleaning in association with products such as toothpaste, soap or water. However, use of an unsuitable toothbrush with a dendrimive may also lead to surface roughness, which allows more microbial colonization [9]. In order to overcome drawbacks of mechanical cleaning, soaking PMMA denture bases in chemical disinfecting agents has gained more acceptance in clinical dentistry due to antimicrobial activity [10]. Chemical agents commonly used for denture cleaning include sodium hypochlorite, glutaraldehyde and chlorine dioxide, 0.12% Chlorhexidine gluconate, sodium perborate and alkaline peroxide [11]. The prosthesis is commonly immersed in the chemical agent for a specific duration for plaque removal and disinfection [11].