title: Antifungal, optical, and mechanical properties of polymethylmethacrylate material incorporated with silanized zinc oxide nanoparticles.
abstract: BACKGROUND
  Fungal infected denture, which is typically composed of polymethylmethacrylate (PMMA), is a common problem for a denture wearer, especially an elderly patient with limited manual dexterity. Therefore, increasing the antifungal effect of denture by incorporating surface modification nanoparticles into the PMMA, while retaining its mechanical properties, is of interest.
  
  
  OBJECTIVE
  This study aimed to evaluate antifungal, optical, and mechanical properties of heat-cured PMMA incorporated with different amounts of zinc oxide nanoparticles (ZnOnps) with or without methacryloxypropyltrimethoxysilane modification.
  
  
  METHODS
  Specimens made from heat-cured PMMA containing 1.25, 2.5, and 5% (w/w) nonsilanized (Nosi) or silanized (Si) ZnOnps were evaluated. Specimens without filler served as control. The fungal assay was performed placing aCandida albicanssuspension on the PMMA surface for 2 h, then Sabouraud Dextrose Broth was added, and growth after 24 h was determined by counting colony forming units on agar plates. A spectrophotometer was used to measure the color in L* (brightness), a* (red-green), b* (yellow-blue) and opacity of the experimental groups. Flexural strength and flexural modulus were determined using a three-point bending test on universal testing machine after 37°C water storage for 48 h and 1 month.
  
  
  RESULTS
  The antifungal, optical, and mechanical properties of the PMMA incorporated with ZnOnps changed depending on the amount. With the same amount of ZnOnps, the silanized groups demonstrated a greater reduction inC. albicanscompared with the Nosi groups. The color difference (ΔE) and opacity of the Nosi groups were greater compared with the Si groups. The flexural strength of the Si groups, except for the 1.25% group, was significantly greater compared with the Nosi groups.
  
  
  CONCLUSIONS
  PMMA incorporated with Si ZnOnps, particularly with 2.5% Si ZnOnps, had a greater antifungal effect, less color differences, and opacity compared with Nosi ZnOnps, while retaining its mechanical properties.
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Krid
authors.initials: K
authors.lastname: Kamonkhantikul
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Mansuang
authors.initials: M
authors.lastname: Arksornnukit
authors.affiliation: Oral Biomaterials Engineering, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Takahashi
mesh_terms: D000704:Analysis of Variance; D000935:Antifungal Agents / Q000494:pharmacology*; D002176:Candida albicans / Q000187:drug effects; D006801:Humans; D008422:Materials Testing; D055595:Mechanical Phenomena; D008689:Methacrylates / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D053758:Nanoparticles / Q000737:chemistry*; D055620:Optical Phenomena; D019904:Polymethyl Methacrylate / Q000494:pharmacology*; D012821:Silanes / Q000494:pharmacology*; D015034:Zinc Oxide / Q000494:pharmacology*
chemical_list: D000935:Antifungal Agents; D008689:Methacrylates; D012821:Silanes; C017492:methacryloxypropyltrimethoxysilane; D019904:Polymethyl Methacrylate; D015034:Zinc Oxide
keywords: antifungal effect; mechanical properties; optical properties; silanized zinc oxide nanoparticles