title: Marginal adaptation and microleakage of Procera AllCeram crowns with four cements.
abstract: OBJECTIVE
  This study investigated the effect of different cements on microleakage and marginal adaptation of porcelain crowns.
  
  
  METHODS
  Eighty extracted molars were divided into two groups. Teeth in one group were prepared to receive Procera AllCeram crowns, whereas the other group was prepared to receive metal-ceramic crowns. Copings were made following standard techniques, and groups were divided for cementation with zinc phosphate, glass-ionomer, resin-modified glassionomer, or resin cement. Specimens were subjected to thermocycling prior to microleakage testing, then sectioned. Microleakage was scored using a five-point scale; marginal adaptation was assessed with a traveling microscope.
  
  
  RESULTS
  A significant association was found between cement type and degree of microleakage. With zinc phosphate, 76% of Procera AllCeram and 90% of metal-ceramic copings exhibited extensive microleakage. With glass-ionomer, 49% of Procera AllCeram and 66% of metal-ceramic copings had 0 microleakage scores; with resin-modified glass-ionomer, 10% of Procera AllCeram and 84% of metal-ceramic copings had 0 microleakage scores. With resin cement, 34% of Procera AllCeram and 96% of metal-ceramic copings exhibited 0 microleakage. Procera AllCeram copings had a significantly larger mean marginal gap (54 microm) compared to metal ceramic (29 microm).
  
  
  CONCLUSIONS
  In both types of crowns, the use of resin cement resulted in the highest percentage of 0 microleakage scores, whereas the zinc phosphate cement resulted in the highest percentage of extensive microleakage.
authors.affiliation: Faculty of Dentistry, University of Toronto, Ontario, Canada. f_albert@videotron.ca
authors.forename: Francine E
authors.initials: FE
authors.lastname: Albert
authors.forename: Omar M
authors.initials: OM
authors.lastname: El-Mowafy
mesh_terms: D000537:Aluminum Oxide; D000704:Analysis of Variance; D001896:Boron Compounds; D002484:Cementation / Q000379:methods*; D003188:Composite Resins; D003442:Crowns; D003763:Dental Leakage; D018772:Dental Marginal Adaptation; D003776:Dental Porcelain; D003799:Dental Stress Analysis; D005899:Glass Ionomer Cements; D006358:Hot Temperature; D006801:Humans; D016015:Logistic Models; D008422:Materials Testing; D016876:Metal Ceramic Alloys; D008689:Methacrylates; D008768:Methylmethacrylates; D008963:Molar; D019279:Resin Cements; D015036:Zinc Phosphate Cement
chemical_list: C105314:AllCeram; D001896:Boron Compounds; D003188:Composite Resins; C061504:Flecks; D005899:Glass Ionomer Cements; D016876:Metal Ceramic Alloys; D008689:Methacrylates; D008768:Methylmethacrylates; D019279:Resin Cements; C084550:Vitremer; D003776:Dental Porcelain; C084541:Fuji glass-ionomer lining cement; D015036:Zinc Phosphate Cement; C049495:Super-bond; D000537:Aluminum Oxide