title: The effect of long-term disinfection procedures on hardness property of resin denture teeth.
abstract: OBJECTIVE
  The aim of the study was to evaluate the effect of long-term disinfection procedures on the Vickers hardness (VHN) of acrylic resin denture teeth.
  
  
  METHODS
  Five acrylic resin denture teeth (Vipi Dent Plus-V, Trilux-T, Biolux-B, Postaris-P and Artiplus-A) and one composite resin denture teeth (SR-Orthosit-O) were embedded in heat-polymerised acrylic resin within polyvinylchloride tubes. Specimens were stored in distilled water at 37°C for 48 h. Measurements of hardness were taken after the following disinfection procedures: immersion for 7 days in 4% chlorhexidine gluconate or in 1% sodium hypochlorite (CIm and HIm group, respectively) and seven daily cycles of microwave sterilisation at 650 W for 6 min (MwS group). In the WIm group, specimens were maintained in water during the time used to perform the disinfection procedures (7 days). Data were analysed with anova followed by the Bonferroni procedure (α = 0.01).
  
  
  RESULTS
  Microwave disinfection decreased the hardness of all acrylic resin denture teeth (p < 0.001). Immersion for 7 days in 4% chlorhexidine gluconate or distilled water had significant effect on the hardness of the acrylic resin denture teeth A (p < 0.01), and 1% sodium hypochlorite on teeth T (p < 0.01). All disinfection procedures decrease the hardness of the composite resin denture teeth (p < 0.01). Teeth O exhibited the highest and teeth V the lowest hardness values in the control group (p < 0.01).
  
  
  CONCLUSIONS
  Disinfection procedures changed the hardness of resin denture teeth.
authors.affiliation: Department of Dentistry, Ponta Grossa State University, Parana, Brazil.
authors.forename: Nara Hellen
authors.initials: NH
authors.lastname: Campanha
authors.forename: Ana Cláudia
authors.initials: AC
authors.lastname: Pavarina
authors.forename: Janaina Habib
authors.initials: JH
authors.lastname: Jorge
authors.forename: Carlos Eduardo
authors.initials: CE
authors.lastname: Vergani
authors.forename: Ana Lucia
authors.initials: AL
authors.lastname: Machado
authors.forename: Eunice Teresinha
authors.initials: ET
authors.lastname: Giampaolo
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry* / Q000528:radiation effects; D002710:Chlorhexidine / Q000031:analogs & derivatives / Q000494:pharmacology; D003188:Composite Resins / Q000737:chemistry / Q000528:radiation effects; D019551:Dental Disinfectants / Q000737:chemistry; D003764:Dental Materials / Q000737:chemistry* / Q000528:radiation effects; D004203:Disinfection / Q000379:methods*; D006244:Hardness; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry / Q000528:radiation effects; D008872:Microwaves / Q000627:therapeutic use; D019904:Polymethyl Methacrylate / Q000737:chemistry / Q000528:radiation effects; D011140:Polyurethanes / Q000737:chemistry / Q000528:radiation effects; D011829:Radiation Dosage; D012973:Sodium Hypochlorite / Q000737:chemistry; D013242:Sterilization / Q000379:methods; D013696:Temperature; D013997:Time Factors; D014093:Tooth, Artificial; D014867:Water / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D003188:Composite Resins; D019551:Dental Disinfectants; D003764:Dental Materials; D008689:Methacrylates; D011140:Polyurethanes; D014867:Water; C029824:urethane dimethacrylate luting resin; C004919:ethylene dimethacrylate; D019904:Polymethyl Methacrylate; D012973:Sodium Hypochlorite; C010882:chlorhexidine gluconate; D002710:Chlorhexidine