title: Comparison of the microshear bond strength of feldspathic porcelain to enamel with three luting resins.
abstract: OBJECTIVE
  The purpose of this study was to compare microshear bond strength of three different luting resins using a new microshear method closely simulating clinical condition.
  
  
  METHODS
  Thirty 1-mm-thick slices of intact human first molars and thirty 0.8-mm-diameter feldspathic porcelain rods were etched by 37% phosphoric acid for enamels and 9.5% hydrofluoric acid for porcelains. Adhesive (Margin bond) was applied on both silaned porcelain and enamel surfaces. Three luting agents were used as follows: (1) dual polymerized cement (DP) (Variolink II refill), (2) light polymerized cement (LP) (Variolink II base), and (3) flow composite (FC) (Tetrick flow). Porcelain rods were attached to flat enamel surfaces followed by cementation. The specimens were thermal cycled for 500 cycles between 5 and 55°C, and microshear test was then performed with wire and loop method using Dillon Quantrol. Modes of failure were identified by stereomicroscope, and one sample of each group was observed with SEM. finally collected data were statistically analyzed using one-way ANOVA (P<.05).
  
  
  RESULTS
  The mean microshear bond strengths were 21.48 (DP), 23.92 (LP) and 24.57 (FC) in MPa units. Most cohesive failures occurred in groups LP and FC, whereas most adhesive failures were observed in group DP.
  
  
  CONCLUSIONS
  Bond strength of feldspathic porcelain to enamel with studied luting resins were not significantly different among the groups based on current method (P<.05).
authors.affiliation: Department of Operative Dentistry and Dental Researcher Center, Faculty of Dentistry, Tehran University of Medical Science, Ghods St, Enghelab Ave, Tehran, Iran. kermanshahhamid@yahoo.com
authors.forename: Hamid
authors.initials: H
authors.lastname: Kermanshah
authors.forename: Atefeh Taheri
authors.initials: AT
authors.lastname: Borougeni
authors.forename: Tahereh
authors.initials: T
authors.lastname: Bitaraf
mesh_terms: D001840:Dental Bonding; D003738:Dental Cements; D003743:Dental Enamel; D003776:Dental Porcelain; D003799:Dental Stress Analysis; D006801:Humans; D066298:In Vitro Techniques; D019279:Resin Cements; D033081:Shear Strength
chemical_list: D003738:Dental Cements; D019279:Resin Cements; D003776:Dental Porcelain