title: Surface topography and bond strengths of feldspathic porcelain prepared using various sandblasting pressures.
abstract: OBJECTIVE
  The purpose of this study was to determine the bond strength of composite resin to feldspathic porcelain and its surface topography after sandblasting at different pressures.
  
  
  METHODS
  In this in vitro study, 68 porcelain disks were fabricated and randomly divided into four groups of 17. The porcelain surface in group 1 was etched with hydrofluoric acid. Groups 2, 3, and 4 were sandblasted at 2, 3 and 4 bars pressure, respectively. Surface topography of seven samples in each of the four groups was examined by a scanning electron microscope (SEM). The remaining 40 samples received the same silane agent, bonding agent, and composite resin and they were then subjected to 5000 thermal cycles and evaluated for shear bond strength. Data were analyzed using one-way anova. The mode of failure was determined using stereomicroscope and SEM.
  
  
  RESULTS
  The highest shear bond strength was seen in group 4. however, statistically significant differences were not seen between the groups (P = 0.780). The most common mode of failure was cohesive in porcelain. The SEM showed different patterns of hydrofluoric acid etching and sandblasting.
  
  
  CONCLUSIONS
  Increasing the sandblasting pressure increased the surface roughness of feldspathic porcelain but no difference in bond strength occurred.
authors.affiliation: Department of Restorative Dentistry, School of Dentistry, Shahed University, Tehran, Iran.
authors.forename: Elham
authors.initials: E
authors.lastname: Moravej-Salehi
authors.affiliation: Private Practice, Tehran, Iran.
authors.forename: Elahe
authors.initials: E
authors.lastname: Moravej-Salehi
authors.affiliation: Department of Restorative Dentistry, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran. azamvalian@yahoo.com.
authors.forename: Azam
authors.initials: A
authors.lastname: Valian
mesh_terms: D000134:Acid Etching, Dental; D020906:Air Abrasion, Dental / Q000379:methods*; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding / Q000379:methods*; D003776:Dental Porcelain / Q000737:chemistry*; D019232:Dental Restoration Failure / Q000706:statistics & numerical data; D003799:Dental Stress Analysis / Q000706:statistics & numerical data; D006858:Hydrofluoric Acid / Q000737:chemistry; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D033081:Shear Strength; D012821:Silanes; D013314:Stress, Mechanical; D013499:Surface Properties
chemical_list: D003188:Composite Resins; D012821:Silanes; D003776:Dental Porcelain; D006858:Hydrofluoric Acid
keywords: air abrasion; ceramic; sandblasting; scanning electron microscopy; shear bond strength