title: Comparison of conventional and plant-extract disinfectant solutions on the hardness and color stability of a maxillofacial elastomer after artificial aging.
abstract: BACKGROUND
  Silicone elastomers undergo physical and chemical degradation with disinfecting solutions. Phytotherapy may be a suitable solution for disinfection. However, its effect on the properties of the silicone material is unknown.
  
  
  OBJECTIVE
  The purpose of this in vitro study was to evaluate the effect of disinfection with conventional and plant-extract solutions and of artificial aging on the hardness and color stability of a facial silicone associated with pigments and an opacifier.
  
  
  METHODS
  Four hundred specimens of silicone (MDX4-4210) were fabricated (5×6 mm). Two pigment shades and 1 dry opacifier were combined in the tested material, and 4 groups (n=10) were obtained: colorless (GI), colorless with opacifier (GII), medium pigment with opacifier (GIII), and black pigment with opacifier (GIV). Specimens were subjected to disinfection (30 days) using saline solution, water, and neutral soap (digital friction, 30 seconds), chlorhexidine 4%, Hydrastis canadensis, and Cymbopogon nardus extracts (immersion, 10 minutes). Shore A hardness (ASTM D2240) and color analyses were performed before and after disinfection. Specimens were then exposed to 1008 hours of artificial aging (ASTM 53) and subjected to final hardness and color readings. The results were analyzed with ANOVA and the Tukey significant difference test (α=.05).
  
  
  RESULTS
  The opacifier increased the hardness (GII). For GII, the H. canadensis solution and the friction with water and soap promoted significantly reduced hardness; the friction also promoted a reduction in this property for GIV. The GIII was not affected after disinfection. A significant difference was found between the ΔE values of the specimens disinfected with H. canadensis, C. nardus, and chlorhexidine, and specimens subjected to saline solution and neutral soap.
  
  
  CONCLUSIONS
  The hardness of MDX4-4210 after the experimental procedure was considered clinically acceptable for facial prostheses. All groups showed clinically unacceptable color alterations regardless of the disinfecting solution.
authors.affiliation: Assistant Professor, Department of Dental Materials and Prosthodontics, Araçatuba Dental School, São Paulo State University (UNESP), São Paulo, Brazil. Electronic address: aimee@foa.unesp.br.
authors.forename: Aimée Maria
authors.initials: AM
authors.lastname: Guiotti
authors.affiliation: Titular Professor, Department of Dental Materials and Prosthodontics, Araçatuba Dental School, São Paulo State University (UNESP), São Paulo, Brazil.
authors.forename: Marcelo Coelho
authors.initials: MC
authors.lastname: Goiato
authors.affiliation: Assistant Professor, Department of Dental Materials and Prosthodontics, Araçatuba Dental School, São Paulo State University (UNESP), São Paulo, Brazil.
authors.forename: Daniela Micheline
authors.initials: DM
authors.lastname: Dos Santos
authors.affiliation: Doctoral student, Department of Dental Materials and Prosthodontics, Araçatuba Dental School, São Paulo State University (UNESP), São Paulo, Brazil.
authors.forename: Aljomar José
authors.initials: AJ
authors.lastname: Vechiato-Filho
authors.affiliation: Graduate student, Department of Dental Materials and Prosthodontics, Araçatuba Dental School, São Paulo State University (UNESP), São Paulo, Brazil.
authors.forename: Bruno Guandalini
authors.initials: BG
authors.lastname: Cunha
authors.affiliation: Graduate student, Department of Dental Materials and Prosthodontics, Araçatuba Dental School, São Paulo State University (UNESP), São Paulo, Brazil.
authors.forename: Marcela Borghi
authors.initials: MB
authors.lastname: Paulini
authors.affiliation: Professor, Oral Patology and Surgery Department, School of Dentistry, Federal University of Minas Gerais, Minas Gerais, Brazil.
authors.forename: Amália
authors.initials: A
authors.lastname: Moreno
authors.affiliation: Professor, Department of Dermatologic, Infectious and Parasitic Diseases, Medical School, FAMERP, São Paulo, Brazil.
authors.forename: Margarete Teresa Gottardo
authors.initials: MT
authors.lastname: de Almeida
mesh_terms: D003116:Color; D004202:Disinfectants / Q000494:pharmacology*; D020724:Elastomers / Q000737:chemistry*; D006244:Hardness; D006801:Humans; D008422:Materials Testing; D008447:Maxillofacial Prosthesis; D017797:Prosthesis Coloring; D012826:Silicone Elastomers; D013997:Time Factors
chemical_list: D004202:Disinfectants; D020724:Elastomers; D012826:Silicone Elastomers