title: Analysis of the properties of silicone rubber maxillofacial prosthetic materials.
abstract: OBJECTIVE
  Maxillofacial prosthetic materials are used to replace facial parts lost through disease or trauma. Silicone rubbers are the materials of choice, however it is widely accepted that these materials do not possess ideal properties. The objective of this study was to assess the properties of a range of commercially available silicone rubber maxillofacial materials and make recommendations for improvements.
  
  
  METHODS
  Specimens of five commonly used maxillofacial materials were prepared in dental flasks according manufacturers instructions. Tear strength, tensile strength, percentage elongation, hardness, water absorption and water contact angles were determined for each material.
  
  
  RESULTS
  The tear strength of Factor II, Cosmesil HC and Nusil were all comparable and significantly higher than Cosmesil St and Prestige (p<0.001). Nusil had a significantly higher tensile strength and elongation in comparison to the other materials (p<0.001) and Cosmesil St and Cosmesil HC were significantly harder (p<0.001). Factor II was significantly less wetted and Prestige and Cosmsesil St had a significantly higher water absorption in comparison to the other materials.
  
  
  CONCLUSIONS
  None of the commercially available silicone rubber materials possessed ideal properties for use as a maxillofacial prosthetic material. Factor II, however, showed more favourable properties due to it's high tear strength, softness and ease of manipulation.
authors.affiliation: Department of Basic Dental Science, University of Wales College of Medicine, Heath Park, Cardiff, UK.
authors.forename: Tariq
authors.initials: T
authors.lastname: Aziz
authors.forename: Mark
authors.initials: M
authors.lastname: Waters
authors.forename: Robert
authors.initials: R
authors.lastname: Jagger
mesh_terms: D000042:Absorption; D000268:Adhesiveness; D001672:Biocompatible Materials / Q000737:chemistry*; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D004548:Elasticity; D006244:Hardness; D006801:Humans; D008422:Materials Testing; D008447:Maxillofacial Prosthesis; D008768:Methylmethacrylates / Q000737:chemistry; D012826:Silicone Elastomers / Q000737:chemistry*; D013499:Surface Properties; D013718:Tensile Strength; D014867:Water / Q000737:chemistry; D017155:Wettability
chemical_list: D001672:Biocompatible Materials; D004129:Dimethylpolysiloxanes; D008768:Methylmethacrylates; D012826:Silicone Elastomers; C044914:cosmesil; C078085:silicone A-2186; D014867:Water; D017438:Bisphenol A-Glycidyl Methacrylate; C029636:Prestige dental material; C013830:baysilon