**Mechanical and Physicochemical Properties of Newly Formed ZnO-PMMA Nanocomposites for Denture Bases**

**Mariusz Cierech 1,\*, Izabela Osica 2,3, Adam Kolenda 1, Jacek Wojnarowicz 4, Dariusz Szmigiel 5, Witold Łojkowski 4, Krzysztof Kurzydłowski 2, Katsuhiko Ariga 3 and ElzbietaMierzwi´ ˙ nska-Nastalska 1**



Received: 21 March 2018; Accepted: 30 April 2018; Published: 6 May 2018

**Abstract:** Aim: The aim of this study was to investigate the selected properties of zinc oxidepolymethyl methacrylate (ZnO-PMMA) nanocomposites that can influence the microorganism deposition on their surface. Materials and Methods: Non-commercial ZnO-NPs were prepared, characterized and used for the preparation of PMMA nanocomposite. Roughness, absorbability, contact angle and hardness of this new nanomaterial were evaluated. PMMA without ZnO-NPs served as control. Outcomes: Compared to unenriched PMMA, incorporation of ZnO-NPs to 7.5% for PMMA nanocomposite increases the hardness (by 5.92%) and the hydrophilicity. After modification of the material with zinc oxide nanoparticles the roughness parameter did not change. All tested materials showed absorption within the range of 1.82 to 2.03%, which meets the requirements of International Organization for Standardization (ISO) standards for denture base polymers. Conclusions: The results showed no significant deterioration in the properties of acrylic resin that could disqualify the nanocomposite for clinical use. Increased hydrophilicity and hardness with absorbability within the normal range can explain the reduced microorganism growth on the denture base, as has been proven in a previous study.

**Keywords:** denture stomatitis; polymethyl methacrylate; zinc oxide nanoparticles; *Candida albicans*
