title: Effects of short-term immersion and brushing with different denture cleansers on the roughness, hardness, and color of two types of acrylic resin.
abstract: OBJECTIVE
  To investigate the cumulative effects of brushing (B) or immersion (I), using different cleansing agents, on the surface roughness, hardness and color stability of a heat-polymerized denture resin, Lucitone 550 (L), and a hard chairside reline resin, Tokuyama Rebase Fast II (T).
  
  
  METHODS
  A total of 316 specimens (10 x 2 mm) were fabricated. The specimens (n = 9) were divided into brushing or immersion groups according to the following agents: dentifrice/distilled water (D), 1% sodium hypochlorite (NaOCl), Corega Tabs (Pb), 1% chlorhexidine gluconate (Chx), and 0.2% peracetic acid (Ac). Brushing and immersion were tested independently. Assays were performed after 1, 3, 21, 45 and 90 brushing cycles or immersion of 10 seconds each. Data were evaluated statistically by repeated measures ANOVA. Tukey's honestly significant difference (HSD) post-hoc test was used to determine differences between means (α = 0.05).
  
  
  RESULTS
  For L there was no statistically significant difference in roughness, except a significant decrease in roughness by brushing with D. T showed a significant effect on the roughness after 90 immersions with Ac. Hardness values decreased for L when specimens were immersed or brushed in NaOCl and Pb. The hardness of T decreased with increases in the repetitions (immersion or brushing), regardless of the cleaning method. Values of color stability for L resin showed significant color change after brushing with and immersion in Ac and Pb. Brushing with D exhibited a higher incidence of color change. For T there were no significant differences between cleaning agents and repetitions in immersion. A color change was noted after three brushings with the Ac, Chx, and D. Brushing with dentifrice decreased roughness of L. Immersion in or brushing with NaOCl and Pb decreased the hardness of L. For T, hardness decreased with increases in immersions or brushing. Color changes after the immersion in or brushing with cleaning agents were clinically acceptable according to National Bureau of Standards parameters for both resins.
authors.forename: Beatriz Helena Dias
authors.initials: BH
authors.lastname: Panariello
authors.forename: Fernanda Emiko
authors.initials: FE
authors.lastname: Izumida
authors.forename: Eduardo Buozi
authors.initials: EB
authors.lastname: Moffa
authors.forename: Ana Claudia
authors.initials: AC
authors.lastname: Pavarina
authors.forename: Janaina Habib
authors.initials: JH
authors.lastname: Jorge
authors.forename: Eunice Teresinha
authors.initials: ET
authors.lastname: Giampaolo
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D002710:Chlorhexidine / Q000031:analogs & derivatives / Q000737:chemistry; D003116:Color; D003764:Dental Materials / Q000737:chemistry*; D003820:Denture Cleansers / Q000737:chemistry*; D003778:Dentures; D006244:Hardness; D006801:Humans; D007101:Immersion; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D010463:Peracetic Acid / Q000737:chemistry; D019904:Polymethyl Methacrylate / Q000737:chemistry; D012973:Sodium Hypochlorite / Q000737:chemistry; D013499:Surface Properties; D014099:Toothbrushing / Q000379:methods*; D014867:Water / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D003764:Dental Materials; D003820:Denture Cleansers; D008689:Methacrylates; C540407:corega tabs; C514244:tokuyama rebase fast II; D014867:Water; C040291:Lucitone; D019904:Polymethyl Methacrylate; D012973:Sodium Hypochlorite; D010463:Peracetic Acid; C010882:chlorhexidine gluconate; D002710:Chlorhexidine