title: Fatigue limits of enamel bonds with moist and dry techniques.
abstract: OBJECTIVE
  Shear fatigue limit (SFL) testing, coupled with shear bond strength (SBS) measurements can provide valuable information regarding the ability of adhesive systems to bond to mineralized tooth structures. The clinical technique for enamel bonding with adhesive resins has shifted from bonding to a thoroughly dried acid conditioned surface to a moist surface to facilitate dentin bonding. The purpose of this study was to compare the performance of ethanol-containing etch-and-rinse adhesive (ERA) systems on moist and dry enamel by determining the resin composite to enamel SBS and SFL, and examining the relationship of SBS and SFL.
  
  
  METHODS
  Twelve specimens each were used to determine 24-h resin composite (Z100 - 3M ESPE) to enamel SBS to moist and dry surfaces with two ERA systems, Adper Single Bond Plus (SBP) and OptiBond Solo Plus (OBP). A staircase method of fatigue testing was used in a four-station fatigue cycler to determine the SFL of resin composite to enamel bonds (moist and dry) with the two ERA systems (20 specimens for each test condition) at 0.25Hz for 40,000 cycles. ANOVA and Tukey's post hoc test were used for the SBS data and a modified t-test with Bonferroni correction was used for comparisons of SFL.
  
  
  RESULTS
  The two ERA systems each generated statistically similar SBS (p>0.05) to moist and dry enamel and the SBS of SBP was significantly higher than OBP on dry enamel (p<0.05). The SFL of SBP was significantly greater to dry enamel when compared to moist enamel and there was not a significant difference in the SFL of OBP on dry and moist enamel. There were no significant differences in SFL values between SBP on either moist or dry enamel and OBP on both moist and dry enamel.
  
  
  CONCLUSIONS
  Fatigue testing may provide more useful information than SBS tests regarding the performance of dental adhesive systems. The chemical composition, solvents and filler components of ERA systems may influence their ability to develop long-term durable bonds to both moist and dry enamel surfaces.
authors.affiliation: Department of General Dentistry, Creighton University School of Dentistry, 2500 California Plaza, Omaha, NE 68178, USA. wbark@creighton.edu
authors.forename: Wayne W
authors.initials: WW
authors.lastname: Barkmeier
authors.forename: Robert L
authors.initials: RL
authors.lastname: Erickson
authors.forename: Mark A
authors.initials: MA
authors.lastname: Latta
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding / Q000379:methods*; D003743:Dental Enamel / Q000648:ultrastructure*; D003799:Dental Stress Analysis / Q000295:instrumentation; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D003890:Desiccation; D000431:Ethanol / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D010756:Phosphoric Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D033081:Shear Strength; D012822:Silicon Dioxide / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013314:Stress, Mechanical; D014867:Water / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry
chemical_list: D003188:Composite Resins; D017220:Dentin-Bonding Agents; C451600:OptiBond Solo Plus; D010756:Phosphoric Acids; D019279:Resin Cements; C511238:Single Bond Plus; D012997:Solvents; C083568:Z100 composite resin; D014867:Water; D000431:Ethanol; D017438:Bisphenol A-Glycidyl Methacrylate; D012822:Silicon Dioxide; D015040:Zirconium; C030242:phosphoric acid