title: Effect of denture cleansers on chemical and mechanical behavior of selected soft lining materials.
abstract: OBJECTIVE
  The aim of this investigation was to determine the effect of storage in disinfectants and artificial saliva on a series of commercial soft lining materials for dentures. Changes in mechanical properties and the nature of chemicals released into these solutions were studied.
  
  
  METHODS
  Four soft lining materials were studied (Vertex Soft® and Villacryl Soft®, both of which are plasticized acrylics; Molloplast B® and Mollosil®, both of which are silicone elastomers). All were cured according to manufacturers' instructions, and then cylindrical specimens (6 mm height × 10 mm diameter) prepared. These were stored under various conditions then loaded in uniaxial compression and the stress measured at a strain corresponding to a 10% deformation to determine Young's modulus. Storage involved exposure either to the following disinfectants: 2% aqueous chlorhexidine gluconate, 2% aqueous sodium hypochlorite, Corega Tabs® cleansing tablets or 3% aqueous hydrogen peroxide; or to artificial saliva. For the latter, storage involved either immersion in artificial saliva at 37°C for the whole study, or immersion for 16h a day and dry at room temperature for the next 8h each day. GC/MS was used to determine species leached into these solutions.
  
  
  RESULTS
  The acrylic materials Villacryl Soft and Vertex Soft became less elastic on storage for up to 28 days whereas the silicone materials Molloplast B and Mollosil, showed no change in elastic properties. Various compounds were found to be released from these materials, including EGDMA, methyl methacrylate and dibutyl phthalate. Generally, the silicones were more stable than acrylics, releasing smaller amounts of the various eluants. In all cases, amounts eluted were well below permitted exposure limits.
  
  
  CONCLUSIONS
  Practical denture cleansing agents affect the properties of soft lining materials, reducing their elastomeric character, acrylics being more adversely affected than the silicones. These changes are associated with the loss of various chemicals, including plasticizers and monomers, from the soft lining materials.
authors.affiliation: Department of Geriatric Dentistry, Poznan University of Medical Sciences, Poznan, Poland.
authors.forename: Rafał
authors.initials: R
authors.lastname: Brożek
authors.forename: Ryszard
authors.initials: R
authors.lastname: Koczorowski
authors.forename: Rafał
authors.initials: R
authors.lastname: Rogalewicz
authors.forename: Adam
authors.initials: A
authors.lastname: Voelkel
authors.forename: Beata
authors.initials: B
authors.lastname: Czarnecka
authors.forename: John W
authors.initials: JW
authors.lastname: Nicholson
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D002710:Chlorhexidine; D019245:Compressive Strength; D019551:Dental Disinfectants; D003799:Dental Stress Analysis; D003820:Denture Cleansers; D003822:Denture Liners; D003993:Dibutyl Phthalate / Q000032:analysis; D004356:Drug Storage; D055119:Elastic Modulus; D006861:Hydrogen Peroxide; D008422:Materials Testing; D008689:Methacrylates / Q000032:analysis; D020366:Methylmethacrylate / Q000032:analysis; D012464:Saliva, Artificial; D012826:Silicone Elastomers / Q000737:chemistry; D012973:Sodium Hypochlorite
chemical_list: D000180:Acrylic Resins; D019551:Dental Disinfectants; D003820:Denture Cleansers; D008689:Methacrylates; D012464:Saliva, Artificial; D012826:Silicone Elastomers; C540407:corega tabs; D020366:Methylmethacrylate; D003993:Dibutyl Phthalate; C004919:ethylene dimethacrylate; D006861:Hydrogen Peroxide; D012973:Sodium Hypochlorite; D002710:Chlorhexidine