title: Microleakage of various cementing agents for full cast crowns.
abstract: OBJECTIVE
  To evaluate microleakage and marginal gaps in full cast crown restorations bonded with six different types of cementing agents.
  
  
  METHODS
  Sixty non-carious human premolars and molars were prepared in a standardized manner for full cast crown restorations. The mesial and distal margins were located in dentin, while the vestibular and palatal/lingual margins were located in enamel. Crowns were made from a high-gold alloy using a standardized technique. The specimens were randomized to six groups of cementing agents: one zinc-phosphate cement (Harvard cement), one conventional glass-ionomer cement (Fuji I), one resin-modified glass-ionomer cement (Fuji Plus), two standard resin cements (RelyX ARC, Panavia F), and one self-adhesive universal resin cement (RelyX Unicem). After 4 weeks of storage in distilled water at 37 degrees C, the specimens were subjected to 5000 thermocycles ranging from 5 to 55 degrees C. Then, they were placed in a silver nitrate solution, embedded in resin blocks, and vertically cut in buccolingual and mesiodistal direction. Subsequently, the objects were evaluated for microleakage and marginal gap using a high-resolution digital microscope camera.
  
  
  RESULTS
  A number of inter-group differences were statistically significant. RelyX Unicem showed the smallest degree of microleakage both in enamel and in dentin. Panavia F und RelyX Unicem were associated with significantly larger marginal gaps than all other cementing agents. No association was observed between microleakage and marginal gap other than a weak direct correlation when using Harvard cement on enamel.
  
  
  CONCLUSIONS
  The cementing agents investigated revealed different sealing abilities. These differences were not associated with specific types of materials.
authors.affiliation: Department of Prosthetic Dentistry, School of Dentistry, Johann Wolfgang Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany. piwowarczyk@t-online.de
authors.forename: Andree
authors.initials: A
authors.lastname: Piwowarczyk
authors.forename: Hans-Christoph
authors.initials: HC
authors.lastname: Lauer
authors.forename: John A
authors.initials: JA
authors.lastname: Sorensen
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate; D003442:Crowns; D001840:Dental Bonding; D003738:Dental Cements / Q000009:adverse effects; D003743:Dental Enamel; D003763:Dental Leakage / Q000209:etiology; D018772:Dental Marginal Adaptation; D003799:Dental Stress Analysis; D003804:Dentin; D005899:Glass Ionomer Cements; D006801:Humans; D008422:Materials Testing; D011092:Polyethylene Glycols; D011109:Polymethacrylic Acids; D011897:Random Allocation; D019279:Resin Cements; D018709:Statistics, Nonparametric; D019231:Tooth Preparation, Prosthodontic; D015036:Zinc Phosphate Cement
chemical_list: D003738:Dental Cements; D005899:Glass Ionomer Cements; C438843:Panavia-Fluoro; D011109:Polymethacrylic Acids; C483701:Rely X Unicem; C462240:RelyX ARC; D019279:Resin Cements; C084541:Fuji glass-ionomer lining cement; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; D015036:Zinc Phosphate Cement; C074226:Harvard Cement