title: Effect of resin cement type on the microtensile bond strength to lithium disilicate ceramic and dentin using different test assemblies.
abstract: OBJECTIVE
  This study evaluated the microtensile bond strength (µTBS) of 3 different resin cements to lithium-disilicate ceramic using two assemblies: ceramic-cement-ceramic (CCC) and ceramic-cement-dentin (CCD).
  
  
  METHODS
  The bonding surfaces of lithium disilicate ceramic blocks (5 × 5 × 4 mm) (Nblock = 90) were etched with 4% hydrofluoric acid for 20 s and silanized. Flat dentin surfaces of human third molars were conditioned according to the respective manufacturer's specifications for three types of resin cements (ML: Multilink, Ivoclar-Vivadent; PF: Panavia F, Kuraray; SB: Super Bond C&B, Sun Medical). While one set of ceramic blocks (n = 30) was cemented to another equal set (CCC assembly), another set of ceramic blocks (n = 30) was cemented on flat dentin (CCD assembly). The bonded specimens were stored in distilled water at 37°C for 24 h, and then sectioned along the x- and y-axes to obtain nontrimmed beam specimens. The beam specimens were randomly divided into two conditions: dry condition (DC - immediate testing); and aging condition (AC - thermocycling 12,000 times + water storage for 150 days). The µTBS bond strength test was performed using a universal testing machine (1 mm/min). After debonding, the substrate and adherent surfaces were analyzed using a scanning electron microscope to categorize the failure types. The data were statistically evaluated using 2-way ANOVA and Tukey's test (5%).
  
  
  RESULTS
  While the mean µTBS of CCC assemblies were significantly influenced by the cement type (p < 0.05) and aging (p < 0.05), CCD assemblies showed a significant effect of the cement (p < 0.05) but not the aging (p > 0.05). Without aging (DC), the mean µTBS (MPa) of SB (26.9) and PF (26.9) were significantly higher than ML (18.5) (p < 0.05). For CCC after aging (AC), SB (26.6) showed higher mean µTBS than those of PF (16.4) and ML (18.5) (p < 0.05). However, in CCD after AC, no significant difference was found between the groups (p > 0.05). In both CCC and CCD assemblies, pre-test failures were the least with SB cement. Regardless of the resin cement type employed and storage conditions, adhesive failures ranged between 35.3% and 88.9%, cohesive failures in cement between 2.3% and 35.3%, and cohesive failures in ceramic between 3.3% and 6.8%.
  
  
  CONCLUSIONS
  SB resin cement demonstrated the highest bond strength to a lithium disilicate ceramic in both tests assemblies with and without aging conditions.
authors.affiliation: Department of Prosthodontics and Dental Materials, Sao Paulo State University, Brazil.
authors.forename: Susana María
authors.initials: SM
authors.lastname: Marocho
authors.forename: Mutlu
authors.initials: M
authors.lastname: Ozcan
authors.forename: Regina
authors.initials: R
authors.lastname: Amaral
authors.forename: Marco Antonio
authors.initials: MA
authors.lastname: Bottino
authors.forename: Luiz Felipe
authors.initials: LF
authors.lastname: Valandro
mesh_terms: D001896:Boron Compounds; D001840:Dental Bonding / Q000379:methods*; D003776:Dental Porcelain / Q000737:chemistry; D003799:Dental Stress Analysis / Q000295:instrumentation*; D003804:Dentin; D017220:Dentin-Bonding Agents / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates; D008768:Methylmethacrylates; D008964:Molar, Third; D019279:Resin Cements / Q000737:chemistry*; D013718:Tensile Strength; D013997:Time Factors
chemical_list: D001896:Boron Compounds; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D008768:Methylmethacrylates; C438843:Panavia-Fluoro; D019279:Resin Cements; C493120:lithia disilicate; C502351:multilink adhesive system; D003776:Dental Porcelain; C049495:Super-bond