title: Porosity of maxillofacial silicone elastomers and microleakage pattern of the commercially pure Ti-silicone elastomer interface after hydrothermal cycling.
abstract: BACKGROUND
  Delamination of the maxillofacial silicone elastomer away from the commercially pure titanium (cpTi)-encapsulated magnets affects the long-term performance of the facial restoration.
  
  
  OBJECTIVE
  The purposes of this in vitro study were to investigate the interfacial microleakage patterns of 2 maxillofacial silicone elastomers with cpTi when 3 different primers were used and to evaluate the porosity of the 2 elastomers tested.
  
  
  METHODS
  To test the interfacial microleakage patterns of the 2 elastomers MDX4-4210 (EL1) and A-2006 (EL2) with cpTi when 3 metal primers, A-304 (PR1), A-320 bonding enhancer (PR2), Super-Bond C&B monomer (PR3), and ethyl-cyanoacrylate (Super Glue) were used, the bonded interfaces were observed using reflected light microscopy, and the percentage of the linear extent of leakage along the interface (%microleakage) was measured. High-resolution x-ray computed microtomography scanning was used to investigate the percentage of void volume fraction (%VF) for both silicone EL1 and EL2. The data were analyzed with 2-way ANOVA and post hoc tests (α=.05).
  
  
  RESULTS
  No statistically significant differences were found among the percentages of PR1, PR2, and PR3 microleakage, whereas ethyl-cyanoacrylate showed a statistically significant higher percentage of microleakage than either of the silicone elastomers (P<.001). EL1 medical grade elastomer groups have always had a statistically significantly higher percentage of microleakage than the EL2 platinum silicone elastomer groups (P<.001). For both elastomers, no statistically significant differences were found in %VF (P=.056).
  
  
  CONCLUSIONS
  Differences in mechanical properties, chemical composition, and manipulations during handling of the maxillofacial silicone elastomers can affect the linear microleakage along the cpTi-silicone elastomer bonding interface and the porosity of the silicone elastomer.
authors.affiliation: Lecturer, Department of Prosthodontics, National and Kapodistrian University of Athens, School of Dentistry, Athens, Greece. Electronic address: iartopoulou@gmail.co.
authors.forename: Ioli Ioanna
authors.initials: II
authors.lastname: Artopoulou
authors.affiliation: Professor, Section of Maxillofacial Prosthodontics and Oncologic Dentistry, Department of Head and Neck Surgery, Division of Surgery, the University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Mark S
authors.initials: MS
authors.lastname: Chambers
authors.affiliation: Professor, Department of Biomaterials, National and Kapodistrian University of Athens, School of Dentistry, Athens, Greece.
authors.forename: George
authors.initials: G
authors.lastname: Eliades
mesh_terms: D000269:Adhesives; D000704:Analysis of Variance; D001896:Boron Compounds; D003487:Cyanoacrylates; D001840:Dental Bonding; D017267:Dental Prosthesis Design; D006801:Humans; D066298:In Vitro Techniques; D008422:Materials Testing; D008447:Maxillofacial Prosthesis; D008689:Methacrylates; D008768:Methylmethacrylates; D016062:Porosity; D012826:Silicone Elastomers / Q000737:chemistry*
chemical_list: D000269:Adhesives; D001896:Boron Compounds; D003487:Cyanoacrylates; D008689:Methacrylates; D008768:Methylmethacrylates; D012826:Silicone Elastomers; C049495:Super-bond