title: Effects of surface treatments and cement types on the bond strength of porcelain-to-porcelain repair.
abstract: OBJECTIVE
  The purpose of this in vitro study was to evaluate the effects of four surface treatments and two resin cements on the repair bond strength of a ceramic primer.
  
  
  METHODS
  Eighty-eight pairs of disks (10 and 5 mm in diameter, 3 mm thickness) were prepared from heat-pressed feldspar ceramics (GC Initial IQ). After being stored in mucin-artificial saliva for 2 weeks, the 10-mm disks were divided into four surface treatment groups (n = 22) and then treated as follows: (1) no treatment (control); (2) 40% phosphoric acid; (3) 5% hydrofluoric acid + acid neutralizer + 40% phosphoric acid; (4) silica coating (CoJet-sand) + 40% phosphoric acid. The 5-mm disks were treated with 5% hydrofluoric acid + 40% phosphoric acid. The two sizes of porcelain disks, excluding the control group, were primed with Clearfil Ceramic Primer. The specimens in each group were further divided into two subgroups of 11 each, and bonded with Clearfil Esthetic Cement (CEC) or Panavia F 2.0 Cement (PFC). The specimens were stored in distilled water at 37°C for 24 hours, thermocycled for 3000 cycles at 5 to 55°C, and stored at 37°C for an additional 7 days. Shear bond strength (SBS) was measured with a universal testing machine at a 0.5 mm/min crosshead speed until fracture. Statistical analysis of the results was carried out with a two-way ANOVA and Tukey HSD test (α = 0.05). Debonded specimen surfaces were examined under an optical microscope to determine the mode of failure.
  
  
  RESULTS
  The statistical analysis showed that the SBS was significantly affected by surface treatment and resin cement (p < 0.05). For treatment groups bonded with CEC, the SBS (MPa) values were (1) 2.64 ± 1.1, (2) 13.31 ± 3.6, (3) 18.88 ± 2.6, (4) 14.27 ± 2.7, while for treatment groups cemented with PFC, the SBS (MPa) values were (1) 3.04 ± 1.1, (2) 16.44 ± 3.3, (3) 20.52 ± 2.2, and (4) 16.24 ± 2.9. All control specimens exhibited adhesive failures, while mixed types of failures were observed in phosphoric acid-treated groups. The other groups revealed mainly cohesive and mixed failures.
  
  
  CONCLUSIONS
  Combined surface treatment of etching with hydrofluoric acid and phosphoric acid provides the highest bond strengths to porcelain. Also, PFC exhibited higher SBS than CEC did.
authors: Department of Oral Health Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI.
authors: Fatma Faiez
authors: FF
authors: Mohamed
authors: Matthew
authors: M
authors: Finkelman
authors: Roya
authors: R
authors: Zandparsa
authors: Hiroshi
authors: H
authors: Hirayama
authors: Gerard
authors: G
authors: Kugel
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000537:Aluminum Oxide / Q000737:chemistry; D000538:Aluminum Silicates / Q000737:chemistry; D001840:Dental Bonding; D045662:Dental Etching / Q000379:methods; D003776:Dental Porcelain / Q000737:chemistry*; D017269:Dental Prosthesis Repair; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D006858:Hydrofluoric Acid / Q000737:chemistry; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D010756:Phosphoric Acids / Q000737:chemistry; D017680:Potassium Compounds / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry*; D012464:Saliva, Artificial / Q000737:chemistry; D033081:Shear Strength; D012821:Silanes / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D000538:Aluminum Silicates; D008689:Methacrylates; C438843:Panavia-Fluoro; D010756:Phosphoric Acids; D017680:Potassium Compounds; D019279:Resin Cements; D012464:Saliva, Artificial; D012821:Silanes; C530542:clearfil esthetic cement; D014867:Water; D003776:Dental Porcelain; C016447:feldspar; C017492:methacryloxypropyltrimethoxysilane; C030242:phosphoric acid; D000537:Aluminum Oxide; D006858:Hydrofluoric Acid
keywords: Shear bond strength; ceramic failure; composite/porcelain repair; silane coupling agent; surface treatments