title: Wear resistance of a modified polymethyl methacrylate artificial tooth compared to five commercially available artificial tooth materials.
abstract: BACKGROUND
  Wear resistance is a limitation of artificial denture teeth. Improving the wear resistance of conventional artificial denture teeth is of value to prosthodontic patients.
  
  
  OBJECTIVE
  The purpose of this in vitro study was to evaluate the wear resistance and hardness of modified polymethyl methacrylate artificial denture teeth compared to 5 commercially available artificial tooth materials.
  
  
  METHODS
  This study evaluated 180 artificial denture teeth (6 groups) that included 3 groups of conventional artificial teeth (MajorDent, Cosmo HXL, and Gnathostar), 2 groups of composite resin artificial teeth (Endura and SR Orthosit PE), and 1 group of modified surface artificial teeth. The flattened buccal surface of each tooth (n=15) was prepared for investigation with the Vickers hardness test and the elucidate wear test (n=15) by using a brushing machine. Each group was loaded for 18,000 cycles, at 2 N, and 150 rpm. The wear value was identified with a profilometer. The data were statistically analyzed by using 1-way ANOVA and post hoc Turkey honestly significant difference tests (α=.001). The tribologies were observed under a scanning electron microscope, and the cytotoxicities were evaluated by MTT assay.
  
  
  RESULTS
  The Vickers hardnesses ranged from 28.48 to 39.36. The wear depths and worn surface area values ranged from 1.12 to 10.79 μm and from 6.74 to 161.95 μm(2). The data revealed that the modified artificial denture teeth were significantly harder and exhibited significantly higher wear resistance than did the conventional artificial teeth (P<.001). The scanning electron microscopic images revealed cross sections of the conventional artificial denture teeth with intensively worn surface areas after brushing. The cytotoxicity test revealed 97.85% cell viability, which indicates the nontoxicity of the modified surface of this material.
  
  
  CONCLUSIONS
  Within the limitations of this study, the polymethyl methacrylate modified surface artificial denture teeth was not significantly different from that of the composite resin artificial denture teeth, with the exceptions that the surface was harder and more wear resistant.
authors.affiliation: Doctoral student, Materials Science and Engineering Program, Faculty of Science, Mahidol University, Bangkok, Thailand.
authors.forename: Pranithida
authors.initials: P
authors.lastname: Kamonwanon
authors.affiliation: Doctoral student, Materials Science and Engineering Program, Faculty of Science, Mahidol University, Bangkok, Thailand.
authors.forename: Sirasa
authors.initials: S
authors.lastname: Yodmongkol
authors.affiliation: Doctoral student, Materials Science and Engineering Program, Faculty of Science, Mahidol University, Bangkok, Thailand.
authors.forename: Rojcharin
authors.initials: R
authors.lastname: Chantarachindawong
authors.affiliation: Associate Professor, Department of Microbiology, Faculty of Dentistry, Mahidol University, Bangkok, Thailand.
authors.forename: Sroisiri
authors.initials: S
authors.lastname: Thaweeboon
authors.affiliation: Professor, Department of Microbiology, Faculty of Dentistry, Mahidol University, Bangkok, Thailand.
authors.forename: Boonyanit
authors.initials: B
authors.lastname: Thaweeboon
authors.affiliation: Assistant Professor, Department of Physics, Faculty of Science, Mahidol University, Bangkok, Thailand. Electronic address: toemsak.sri@mahidol.ac.th.
authors.forename: Toemsak
authors.initials: T
authors.lastname: Srikhirin
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry / Q000633:toxicity; D001672:Biocompatible Materials / Q000737:chemistry / Q000633:toxicity; D003188:Composite Resins / Q000737:chemistry / Q000633:toxicity; D003764:Dental Materials / Q000737:chemistry* / Q000633:toxicity; D019554:Dental Restoration Wear; D006244:Hardness; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D053761:Nanocomposites / Q000737:chemistry / Q000633:toxicity; D019904:Polymethyl Methacrylate / Q000737:chemistry* / Q000633:toxicity; D011140:Polyurethanes / Q000737:chemistry / Q000633:toxicity; D012821:Silanes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D014093:Tooth, Artificial; D014099:Toothbrushing / Q000295:instrumentation
chemical_list: D000180:Acrylic Resins; D001672:Biocompatible Materials; D003188:Composite Resins; D003764:Dental Materials; D011140:Polyurethanes; D012821:Silanes; C513704:Isosit; D012822:Silicon Dioxide; D019904:Polymethyl Methacrylate