title: In vitro shear bond strength of cementing agents to fixed prosthodontic restorative materials.
abstract: BACKGROUND
  Durable bonding to fixed prosthodontic restorations is desirable; however, little information is available on the strength of the bond between different cements and fixed prosthodontic restorative materials.
  
  
  OBJECTIVE
  This study determined the shear-bond strength of cementing agents to high-gold-content alloy castings and different dental ceramics: high-strength aluminum oxide (Procera AllCeram), leucite-reinforced (IPS Empress), and lithium disilicate glass-ceramic (IPS Empress 2).
  
  
  METHODS
  Prepolymerized resin composite cylinders (5.5 mm internal diameter, n=20) were bonded to the pretreated surfaces of prosthodontic materials. High-gold-content alloy and high-strength aluminum oxide surfaces were airborne-particle-abraded, and pressable ceramics were hydrofluoric acid-etched and silanized prior to cementing. The cementing agents tested were a zinc-phosphate cement (Fleck's zinc cement), glass ionomer cements (Fuji I, Ketac-Cem), resin-modified glass ionomer cements (Fuji Plus, Fuji Cem, RelyX Luting), resin cements (RelyX ARC, Panavia F, Variolink II, Compolute), and a self-adhesive universal resin cement (RelyX Unicem). Half the specimens (n=10) were tested after 30 minutes; the other half (n=10) were stored in distilled water at 37 degrees C for 14 days and then thermal cycled 1000 times between 5 degrees C and 55 degrees C prior to testing. Shear-bond strength tests were performed using a universal testing machine at a constant crosshead speed of 0.5 mm/min. Statistical analysis was performed by multifactorial analysis of variance taking interactions between effects into account. For multiple paired comparisons, the Tukey method was used (alpha=.05).
  
  
  RESULTS
  In a 3-way ANOVA model, the main factors substrate, cement, time, and all corresponding interactions were statistically significant (all P <.0001). In subsequent separate 1-way or 2-way ANOVA models for each substrate type, significant differences between cement types and polymerizing modes were found (all P <.001). None of the cement types provided the highest bonding values with all substrate types.
  
  
  CONCLUSIONS
  After 14 days of water storage followed by thermal cycling, only the self-adhesive universal resin cement (RelyX Unicem) and 2 of the resin cements (Panavia F and Compolute) exhibited strong bond strengths to specific prosthodontic materials. In contrast, zinc-phosphate, glass ionomer, and resin-modified glass ionomer cements showed the lowest values of all tested cementing agents after 14 days of water storage followed by thermal cycling.
authors.affiliation: Department of Prosthetic Dentistry, Johann Wolfgang Goethe University, 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: D000134:Acid Etching, Dental; D020906:Air Abrasion, Dental; D000537:Aluminum Oxide / Q000737:chemistry; D000704:Analysis of Variance; D001840:Dental Bonding; D003734:Dental Casting Investment / Q000737:chemistry; D003738:Dental Cements / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry; D017266:Dental Prosthesis; D003799:Dental Stress Analysis / Q000295:instrumentation; D005899:Glass Ionomer Cements / Q000737:chemistry; D006047:Gold Alloys / Q000737:chemistry; D006801:Humans; D006858:Hydrofluoric Acid / Q000737:chemistry; D016555:Matched-Pair Analysis; D008422:Materials Testing; D019279:Resin Cements / Q000737:chemistry; D033081:Shear Strength; D012821:Silanes / Q000737:chemistry; D015036:Zinc Phosphate Cement / Q000737:chemistry
chemical_list: D003734:Dental Casting Investment; D003738:Dental Cements; D003764:Dental Materials; D005899:Glass Ionomer Cements; D006047:Gold Alloys; D019279:Resin Cements; D012821:Silanes; D003776:Dental Porcelain; D015036:Zinc Phosphate Cement; D000537:Aluminum Oxide; D006858:Hydrofluoric Acid