title: Effect of bracket base design on shear bond strength to feldspathic porcelain.
abstract: OBJECTIVE
  This study sought to assess the effect of bracket base design on the shear bond strength (SBS) of the bracket to feldspathic porcelain.
  
  
  METHODS
  This in vitro, experimental study was conducted on 40 porcelain-fused-to-metal restorations and four different bracket base designs were bonded to these specimens. The porcelain surfaces were etched, silanized, and bonded to brackets. Specimens were thermocycler, incubated for 24 h and were subjected to SBS. Data were analyzed using Shapiro-Wilk test, Levene's test, one-way ANOVA, and Tukey's honest significant difference test. Adhesive remnant index was calculated and compared using Fisher's exact test.
  
  
  RESULTS
  One-way ANOVA showed that the SBS values were significantly different among the four groups (P < 0.001). Groups 1, 2, and 4 were not significantly different, but group 3 had significantly lower SBS (P < 0.001). Fractures mostly occurred at the porcelain-adhesive interface in Groups 1 and 2 while in Groups 3 and 4, bracket-adhesive and mixed failures were more common.
  
  
  CONCLUSIONS
  The bracket base design significantly affects the SBS to feldspathic porcelain.
authors.affiliation: Department of Orthodontics, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Kazem
authors.initials: K
authors.lastname: Dalaie
authors.affiliation: General Dentistry Student, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Armin
authors.initials: A
authors.lastname: Mirfasihi
authors.affiliation: Department of Dental Materials, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Solmaz
authors.initials: S
authors.lastname: Eskandarion
authors.affiliation: Department of Orthodontics, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Sattar
authors.initials: S
authors.lastname: Kabiri
keywords: Bond strength; dental porcelain; orthodontic brackets