title: Durability of adhesion between feldspathic ceramic and resin cements: effect of adhesive resin, polymerization mode of resin cement, and aging.
abstract: OBJECTIVE
  Adhesive cementation is an important step for restorations made of feldspathic ceramic as it increases the strength of such materials. Incorrect selection of the adhesive resin and the resin cement to adhere to the ceramic surface and their durability against aging can affect the adhesion between these materials and the clinical performance. This study evaluated the effect of adhesive resins with different pHs, resin cements with different polymerization modes, and aging on the bond strength to feldspathic ceramic.
  
  
  METHODS
  One surface of feldspathic ceramic blocks (VM7) (N = 90) (6.4 × 6.4 × 4.8 mm(3) ) was conditioned with 10% hydrofluoric acid for 20 seconds, washed/dried, and silanized. Three adhesive resins (Scotchbond Multi-Purpose Plus [SBMP], pH: 5.6; Single Bond [SB], pH: 3.4; and Prime&Bond NT [NT], pH: 1.7) were applied on the ceramic surfaces (n = 30 per adhesive). For each adhesive group, three resin cements with different polymerization modes were applied (n = 10 per cement): photo-polymerized (Variolink II base), dual polymerized (Variolink II base + catalyst), and chemically polymerized (C&B). The bonded ceramic blocks were stored in water (37°C) for 24 hours and sectioned to produce beam specimens (cross-sectional bonded area: 1 ± 0.1 mm(2) ). The beams of each block were randomly divided into two conditions: Dry, microtensile test immediately after cutting; TC, test was performed after thermocycling (12,000×, 5°C to 55°C) and water storage at 37°C for 150 days. Considering the three factors of the study (adhesive [3 levels], resin cement [3 levels], aging [2 levels]), 18 groups were studied. The microtensile bond strength data were analyzed using 3-way ANOVA and Tukey's post hoc test (α= 0.05).
  
  
  RESULTS
  Adhesive resin type (p < 0.001) and the resin cement affected the mean bond strength (p= 0.0003) (3-way ANOVA). The NT adhesive associated with the chemically polymerized resin cement in both dry (8.8 ± 6.8 MPa) and aged conditions (6.9 ± 5.9 MPa) presented statistically lower bond strength results, while the SBMP adhesive resin, regardless of the resin cement type, presented the highest results (15.4 to 18.5 and 14.3 to 18.9 MPa) in both dry and aged conditions, respectively (Tukey's test).
  
  
  CONCLUSIONS
  Application of a low-pH adhesive resin onto a hydrofluoric acid etched and silanized feldspathic ceramic surface in combination with chemically polymerized resin cement did not deliver favorable results. The use of adhesive resin with high pH could be clinically advised for the photo-, dual-, and chemically polymerized resin cements tested.
authors.affiliation: São José dos Campos Dental School, São Paulo State University at São José dos Campos, Brazil.
authors.forename: Aleska
authors.initials: A
authors.lastname: Vanderlei
authors.forename: Sheila Pestana
authors.initials: SP
authors.lastname: Passos
authors.forename: Mutlu
authors.initials: M
authors.lastname: Özcan
authors.forename: Marco Antonio
authors.initials: MA
authors.lastname: Bottino
authors.forename: Luiz Felipe
authors.initials: LF
authors.lastname: Valandro
mesh_terms: D000268:Adhesiveness; D000538:Aluminum Silicates; D017438:Bisphenol A-Glycidyl Methacrylate; D001840:Dental Bonding / Q000379:methods; D003776:Dental Porcelain / Q000737:chemistry; D003799:Dental Stress Analysis; D006863:Hydrogen-Ion Concentration; D058105:Polymerization; D011109:Polymethacrylic Acids; D017680:Potassium Compounds; D019279:Resin Cements / Q000737:chemistry; D013718:Tensile Strength; D013997:Time Factors
chemical_list: D000538:Aluminum Silicates; D011109:Polymethacrylic Acids; D017680:Potassium Compounds; C425843:Prime and Bond NT; D019279:Resin Cements; C425844:Scotchbond Multi-Purpose Plus; C115612:single bond; D003776:Dental Porcelain; C016447:feldspar; D017438:Bisphenol A-Glycidyl Methacrylate