title: Shear-peel bond strength of orthodontic primers in wet conditions.
abstract: OBJECTIVE
  The purpose of this in vitro study was to determine whether a hydrophilic primer (Transbond MIP, [MIP]) produces a significant difference in shear/peel bond strength compared with a traditional hydrophobic primer (Transbond XT, [XT]) in wet (W) or dry (D) conditions and if there is a difference in the site of bond failure.
  
  
  METHODS
  A randomized blinded in vitro design.
  
  
  METHODS
  The University of Missouri-Kansas City School of Dentistry. Forty extracted human premolars were divided into four test groups (n = 10 each): MIP-dry conditions (MIPD), MIP-wet conditions (MIPW), XT-dry (XTD) and XT-wet (XTW).
  
  
  METHODS
  Orthodontic brackets were bonded to the teeth according to the manufacturer's directions except XTW and MIPW were exposed to moisture.
  
  
  METHODS
  Shear/peel test 24 h after bonding using an Instron at a crosshead speed of 0.5 mm/min and the adhesive remnant index to determine the site of bond failure.
  
  
  RESULTS
  The bond strengths (X +/- SD) in MPa were XTD = 8.3 +/- 2.3; XTW = 0.8 +/- 0.7; MIPD = 7.5 +/- 1.8 and MIPW = 7.9 +/- 1.7. The shear/peel bond strengths were significantly different: XTD = MIPD = MIPW > XTW (p < or = 0.01; two-way ANOVA; Tukey HSD). The ARI scores were also significantly different: XTD = MIPD = MIPW > XTW (p < or = 0.01; Chi-square).
  
  
  CONCLUSIONS
  Orthodontists who suspect moisture contamination should use a hydrophilic primer during bonding procedures to maintain shear/peel bond strength.
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, University of Missouri-Kansas City, Kansas City, MO 64108, USA. kulak@umkc.edu
authors.forename: K S
authors.initials: KS
authors.lastname: Kula
authors.forename: T D
authors.initials: TD
authors.lastname: Nash
authors.forename: J H
authors.initials: JH
authors.lastname: Purk
mesh_terms: D000269:Adhesives; D000704:Analysis of Variance; D001641:Bicuspid; D017438:Bisphenol A-Glycidyl Methacrylate; D016009:Chi-Square Distribution; D001840:Dental Bonding; D003799:Dental Stress Analysis; D000431:Ethanol; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008422:Materials Testing; D008689:Methacrylates; D016910:Orthodontic Brackets; D019279:Resin Cements; D033081:Shear Strength; D014867:Water; D017155:Wettability
chemical_list: D000269:Adhesives; D008689:Methacrylates; D019279:Resin Cements; C458821:Transbond moisture-insensitive primer; D014867:Water; C065742:Transbond; D000431:Ethanol; D017438:Bisphenol A-Glycidyl Methacrylate