title: Influence of Etching Protocol and Silane Treatment with a Universal Adhesive on Lithium Disilicate Bond Strength.
abstract: OBJECTIVE
  To measure the effects of hydrofluoric acid (HF) etching and silane prior to the application of a universal adhesive on the bond strength between lithium disilicate and a resin.
  
  
  METHODS
  Sixty blocks of lithium disilicate (e.max CAD, Ivoclar Vivadent) were sectioned into coupons and polished. Specimens were divided into six groups (n=10) based on surface pretreatments, as follows: 1) no treatment (control); 2) 5% HF etch for 20 seconds (5HF); 3) 9.5% HF etch for 60 seconds (9.5HF); 4) silane with no HF (S); 5) 5% HF for 20 seconds + silane (5HFS); and 6) 9.5% HF for 60 seconds + silane (9.5HFS). All etching was followed by rinsing, and all silane was applied in one coat for 20 seconds and then dried. The universal adhesive (Scotchbond Universal, 3M ESPE) was applied onto the pretreated ceramic surface, air thinned, and light cured for 10 seconds. A 1.5-mm-diameter plastic tube filled with Z100 composite (3M ESPE) was applied over the bonded ceramic surface and light cured for 20 seconds on all four sides. The specimens were thermocycled for 10,000 cycles (5°C-50°C/15 s dwell time). Specimens were loaded until failure using a universal testing machine at a crosshead speed of 1 mm/min. The peak failure load was used to calculate the shear bond strength. Scanning electron microscopy images were taken of representative e.max specimens from each group.
  
  
  RESULTS
  A two-way analysis of variance (ANOVA) determined that there were significant differences between HF etching, silane treatment, and the interaction between HF and silane treatment (p<0.01). Silane treatment provided higher shear bond strength regardless of the use or concentration of the HF etchant. Individual one-way ANOVA and Tukey post hoc analyses were performed for each silane group. Shear bond strength values for each etch time were significantly different (p<0.01) and could be divided into significantly different groups based on silane treatment: no silane treatment: 0 HF < 5% HF < 9.5% HF; and RelyX silane treatment: 0 HF < 5% HF and 9.5% HF.
  
  
  CONCLUSIONS
  Both HF and silane treatment significantly improved the bond strength between resin and lithium disilicate when used with a universal adhesive.
authors.forename: V K
authors.initials: VK
authors.lastname: Kalavacharla
authors.forename: N C
authors.initials: NC
authors.lastname: Lawson
authors.forename: L C
authors.initials: LC
authors.lastname: Ramp
authors.forename: J O
authors.initials: JO
authors.lastname: Burgess
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods*; D000704:Analysis of Variance; D001840:Dental Bonding / Q000379:methods*; D003738:Dental Cements; D045662:Dental Etching / Q000379:methods*; D003776:Dental Porcelain; D006858:Hydrofluoric Acid; D066298:In Vitro Techniques; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D012821:Silanes; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D003738:Dental Cements; D012821:Silanes; C493120:lithia disilicate; D003776:Dental Porcelain; D006858:Hydrofluoric Acid