title: Effect of Saliva pH on Shear Bond Strength of Orthodontic Brackets.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the effect of salivary pH on the shear bond strength (SBS) of orthodontic brackets to tooth surface.
  
  
  METHODS
  Eighty intact premolars were randomly divided into four groups of 20. After bonding a bracket on each tooth, the groups one to four were stored in artificial saliva at a pH of 3.8, 4.8, 5.8, and 6.8, respectively for two months. The artificial saliva solutions were refreshed weekly. Each tooth was then embedded in an acrylic block so that the crown was exposed and its buccal surface was parallel to the direction of the force during SBS testing. All brackets were debonded using Dartec universal testing machine, and the mean values of SBS in different groups were compared using one-way analysis of variance (ANOVA).
  
  
  RESULTS
  The mean SBS value in group one (pH 3.8) was significantly lower than that in other groups (P<0.05). The differences between other groups were not significant (P>0.05).
  
  
  CONCLUSIONS
  Decreased salivary pH due to poor oral hygiene and/or frequent consumption of acidic beverages may be responsible for orthodontic bracket bond failure.
authors.affiliation: Associate Professor, Department of Orthodontics, Faculty of Dentistry, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
authors.forename: Mohammad Hossein
authors.initials: MH
authors.lastname: Toodehzaeim
authors.affiliation: Assistant Professor, Department of Orthodontics, Faculty of Dentistry, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
authors.forename: Elham
authors.initials: E
authors.lastname: Khanpayeh
keywords: Orthodontic Brackets; Saliva; Shear Strength