## 4 Discussion  
The current study was conducted to evaluate the cumulative effect of microwave disinfection and a denture cleaning tablet (sodium perborate) with reduced time and power on the elimination of bacterial biofilm from PMMA denture base resin. It was based on the hypothesis that there will be no significant difference in cleaning efficacy of DC, MW and their combination on the disinfection of _E. coli, S. aureus_ and _S. mutans_ incubated on the PMMA denture base. Therefore, the postulated hypothesis was rejected, as all the tested groups displayed variable results of denture disinfection as compared to the control. The possibility that a dental prosthesis can be a cause of infection and cross-contamination between patients and dental staff additionally stresses the need for disinfection [17]. Dental appliance disinfection poses a significant problem for clinicians, particularly with regards to removable dentures [18]. The results of the present study revealed that zero mean CFU was obtained after exposing PMMA to MW irradiation in combination with DC within 2 min (MW-DW-DC). In comparison, zero mean CFU for samples exposed to microwave alone (MW + DW) was obtained at 3 min. The one-minute exposure of acrylic specimen  
Figure 5: **(A)** Micrograph of biofilm positive consortia harboring cocci and bacilli. **(B)** Observe the attachment of mixture of live cells _E. coli_ (rods) _S. aureus_ and _S. mutans_ (Cocci) on PMMA prior to disinfection. **(C)** Dead cells attached to the surface of acrylic slide, disinfected by exposure to MW at 450 W for 1 min (24 h). **(D)** Dead cells attached to the PMMA surface, disinfected by exposure to MW at 450 W for 1 min (48 h). **(E)** Dead cells on PMMA surface disinfected by MW with DC for 2 min (36 h). **(F)** PMMA surface disinfected with DW with DC for 5 min (24 h). to MW irradiation showed 50% reduction in CFU for _E. coli_, 24% for _S. aureus_ and 96% for _S. mutans_. Conversely, the combination of MW and DC resulted in 97% reduction of _E. coli_ count, 96% for _S. aureus_ and 100% for _S. mutans_ after 1 min of exposure. Thus, a combination of MW irradiation with DC showed higher disinfection percentage of bacterial species in disinfection of PMMA polymer denture bases compared to MW and DC alone. Considering the effectiveness of microwave disinfection, its role for denture decontamination has gained much attention in the past [19]. Multiple previous pieces of research have used variable time and power to ascertain its efficacy for denture disinfection [20]. [PERSON] et al. first identified that an unmodified domestic microwave can perform denture disinfection [10]. In the present study, the efficacy of microwave irradiation on acrylic resin contaminated with bacterial biofilm at different growth hours (24-36-48-96 h) was investigated keeping the power 450 W and irradiation time 1, 2 and 3 min. From the results, it was found that exposure to microwave irradiation took 3 min to achieve complete CFU count zero, i.e., complete removal of _S. aureus_, _S. mutans_ and _E. coli_ from acrylic slides. Moreover, comparative analysis revealed that the increase in incubation period to 36 h resulted in an increased CFU count. However, this increase in count has not shown any impact on the disinfection capabilities of microwave radiation. These results are in line with the outcomes of the studies conducted by [PERSON] et al. and [PERSON] et al. [21; 22]. These findings may be due to the fact that microwave irradiation alters structural integrity and cell membrane permeability [23]. It also has detrimental effects on cell metabolism, thus leading to bacterial cell death. In contrast to microwave disinfection of PMMA polymer bases, a combination of chemical disinfection (denture cleaning tablets) and microwaving effectively and efficaciously disinfects the material faster than microwaving alone, within 2 min of exposure time [24].