title: Surface Coating of Gypsum-Based Molds for Maxillofacial Prosthetic Silicone Elastomeric Material: The Surface Topography.
abstract: OBJECTIVE
  This study aimed to compare the surface roughness of maxillofacial silicone elastomers fabricated in noncoated and coated gypsum materials. This study was also conducted to characterize the silicone elastomer specimens after surfaces were modified.
  
  
  METHODS
  A gypsum mold was coated with clear acrylic spray. The coated mold was then used to produce modified silicone experimental specimens (n = 35). The surface roughness of the modified silicone elastomers was compared with that of the control specimens, which were prepared by conventional flasking methods (n = 35). An atomic force microscope (AFM) was used for surface roughness measurement of silicone elastomer (unmodified and modified), and a scanning electron microscope (SEM) was used to evaluate the topographic conditions of coated and noncoated gypsum and silicone elastomer specimens (unmodified and modified) groups. After the gypsum molds were characterized, the fabricated silicone elastomers molded on noncoated and coated gypsum materials were evaluated further. Energy-dispersive X-ray spectroscopy (EDX) analysis of gypsum materials (noncoated and coated) and silicone elastomer specimens (unmodified and modified) was performed to evaluate the elemental changes after coating was conducted. Independent t test was used to analyze the differences in the surface roughness of unmodified and modified silicone at a significance level of p < 0.05.
  
  
  RESULTS
  Roughness was significantly reduced in the silicone elastomers processed against coated gypsum materials (p < 0.001). The AFM and SEM analysis results showed evident differences in surface smoothness. EDX data further revealed the presence of the desired chemical components on the surface layer of unmodified and modified silicone elastomers.
  
  
  CONCLUSIONS
  Silicone elastomers with lower surface roughness of maxillofacial prostheses can be obtained simply by coating a gypsum mold.
authors.affiliation: Prosthodontics Unit, Faculty of Dentistry, Universiti Sains Malaysia, Kelantan, Malaysia.|Prosthodontics Unit, University of Anbar, Anbar, Iraq.
authors.forename: Salah
authors.initials: S
authors.lastname: Khalaf
authors.affiliation: Prosthodontics Unit, Faculty of Dentistry, Universiti Sains Malaysia, Kelantan, Malaysia.
authors.forename: Zaihan
authors.initials: Z
authors.lastname: Ariffin
authors.affiliation: Prosthodontics Unit, Faculty of Dentistry, Universiti Sains Malaysia, Kelantan, Malaysia.
authors.forename: Adam
authors.initials: A
authors.lastname: Husein
authors.affiliation: Prosthodontics Unit, Faculty of Dentistry, Universiti Sains Malaysia, Kelantan, Malaysia.
authors.forename: Fazal
authors.initials: F
authors.lastname: Reza
mesh_terms: D002133:Calcium Sulfate; D008422:Materials Testing; D008447:Maxillofacial Prosthesis; D011474:Prosthesis Design; D012826:Silicone Elastomers; D013499:Surface Properties
chemical_list: D012826:Silicone Elastomers; D002133:Calcium Sulfate
keywords: Maxillofacial prosthesis; silicone elastomers; surface modification; surface topography