title: Effects of the peracetic acid and sodium hypochlorite on the colour stability and surface roughness of the denture base acrylic resins polymerised by microwave and water bath methods.
abstract: OBJECTIVE
  This study evaluated the surface roughness (Ra) and color stability of acrylic resin colors (Lucitone 550, QC-20 and Vipi-Wave) used for fabricating bases for complete, removable dentures, overdentures and prosthetic protocol after immersion in chemical disinfectants (1% sodium hypochlorite and 2% peracetic acid) for 30 and 60 minutes.
  
  
  METHODS
  Sixty specimens were made of each commercial brand of resin composite, and divided into 2 groups according to the chemical disinfectants. Specimens had undergone the finishing and polishing procedures, the initial color and roughness measurements were taken (t=0), and after this, ten test specimens of each commercial brand of resin composite were immersed in sodium hypochlorite and ten in peracetic acid, for 30 and 60 minutes, with measurements being taken after each immersion period. These data were submitted to statistical analysis.
  
  
  RESULTS
  There was evidence of an increase in Ra after 30 minutes immersion in the disinfectants in all the resins, with QC-20 presenting the highest Ra values, and Vipi-Wave the lowest. After 60 minutes immersion in the disinfectants all the resins presented statistically significant color alteration.
  
  
  CONCLUSIONS
  Disinfection with 1% sodium hypochlorite and peracetic acid altered the properties of roughness and color of the resins.
authors.affiliation: Department of Dental Materials and Prosthodontics, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil. flaviocarrico@forp.usp.br
authors.forename: Flavio H C N
authors.initials: FH
authors.lastname: Fernandes
authors.forename: Iara A
authors.initials: IA
authors.lastname: Orsi
authors.forename: Camilo A
authors.initials: CA
authors.lastname: Villabona
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry* / Q000528:radiation effects; D003116:Color; D003188:Composite Resins / Q000737:chemistry; D019551:Dental Disinfectants / Q000737:chemistry*; D003775:Dental Polishing; D003819:Denture Bases; D006801:Humans; D008422:Materials Testing; D008872:Microwaves; D010463:Peracetic Acid / Q000737:chemistry*; D058105:Polymerization; D012973:Sodium Hypochlorite / Q000737:chemistry*; D013499:Surface Properties; D013997:Time Factors; D014867:Water / Q000737:chemistry*
chemical_list: D000180:Acrylic Resins; D003188:Composite Resins; D019551:Dental Disinfectants; C488492:QC 20 (denture base resin); C539102:vipi wave; D014867:Water; C040291:Lucitone; D012973:Sodium Hypochlorite; D010463:Peracetic Acid