*Article* **Bacterial Disinfection of Polymethyl Methacrylate (PMMA) Resin Polymer Using Low Level Microwave Irradiation and Denture Cleaning Agent**

**Ziaullah Choudhry 1,\*, Syed M. R. Kazmi 2, Sofia Malik 3, Zulfiqar A. Mirani 4, Shahbaz Ahmed 5, Fazal Ur Rehman Qazi 5, Muhammad Adeel Ahmed <sup>6</sup> , Mohammed Alrabiah 7, Khulud A. AlAali 8, Fahim Vohra 7,\* and Tariq Abduljabbar <sup>7</sup>**

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**Abstract:** The aim was to evaluate the disinfection of *E. coli*, *S. aureus* and *S. mutans* cultured on Polymethyl Methacrylate (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* ≤ 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*.

**Keywords:** polymers; polymethyl methacrylate; bacteria; disinfection; oral health

**Citation:** Choudhry, Z.; Kazmi, S.M.R.; Malik, S.; Mirani, Z.A.; Ahmed, S.; Rehman Qazi, F.U.; Ahmed, M.A.; Alrabiah, M.; AlAali, K.A.; Vohra, F.; et al. Bacterial Disinfection of Polymethyl Methacrylate (PMMA) Resin Polymer Using Low Level Microwave Irradiation and Denture Cleaning Agent. *Appl. Sci.* **2022**, *12*, 5860. https://doi.org/10.3390/ app12125860

Academic Editor: Mary Anne Melo

Received: 8 May 2022 Accepted: 2 June 2022 Published: 9 June 2022

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