title: Effect of chlorhexidine and ethanol on push-out bond strength of fiber posts under cyclic loading.
abstract: OBJECTIVE
  To investigate the effects of pretreatment with 2% chlorhexidine in a gel base (CHX) and 100% ethanol (EtOH) on the bond strength between fiber posts relined with resin composite and root dentin under cyclic loading.
  
  
  METHODS
  Forty bovine incisor roots were divided into four groups after phosphoric acid etching: group 1 (control), irrigation with physiological saline solution; group 2, 5 min pretreatment with CHX; group 3, 1 min pretreatment with EtOH; group 4, 5 min pretreatment with CHX followed by 1 min with EtOH. Fiber posts relined with resin composite were cemented with RelyX ARC and the etch-and-rinse adhesive system Scotchbond Multi-Purpose. Each group was randomly divided into two subgroups: 24 h of storage (immediate groups) and cyclic loading (loading groups) with 250,000 cycles in a controlled chewing simulator. All roots were sectioned transversely and push-out tests were performed. Failure modes were observed and the bond strength means were analyzed using ANOVA and Tukey's test (a = 0.05).
  
  
  RESULTS
  The mean values for the bond strength test (MPa) in immediate groups were: group 1, 5.44 ± 1.48; group 2, 5.57 ± 1.41; group 3, 5.49 ± 1.48; group 4, 5.57 ± 1.42. Immediate groups showed similar bond strength values (p > 0.05). In the cyclic loading groups, the bond strength values were: group 1, 2.80 ± 0.79; group 2, 4.02 (1.30); group 3, 4.50 ± 1.67; group 4, 4.97 ± 2.00. After cyclic loading, a significant decrease in the control group was observed (p < 0.05), while CHX pretreatment resulted in intermediate values (p < 0.05) and EtOH alone or associated with CHX preserved the bond strength values (p > 0.05).
  
  
  CONCLUSIONS
  Chlorhexidine and/or ethanol pretreatment preserved the bond strength of the fiber post after cyclic loading.
authors.forename: Doglas
authors.initials: D
authors.lastname: Cecchin
authors.forename: Mateus
authors.initials: M
authors.lastname: Giacomin
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Farina
authors.forename: Cláudia Lopes
authors.initials: CL
authors.lastname: Bhering
authors.forename: Marcelo Ferraz
authors.initials: MF
authors.lastname: Mesquita
authors.forename: Caio Cezar
authors.initials: CC
authors.lastname: Ferraz
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000818:Animals; D000891:Anti-Infective Agents, Local / Q000737:chemistry*; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002417:Cattle; D002710:Chlorhexidine / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003786:Dental Pulp Cavity / Q000648:ultrastructure; D003804:Dentin / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry; D000431:Ethanol / Q000737:chemistry*; D008422:Materials Testing; D010756:Phosphoric Acids / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D011176:Post and Core Technique / Q000295:instrumentation*; D011897:Random Allocation; D019279:Resin Cements / Q000737:chemistry; D012388:Root Canal Irrigants / Q000737:chemistry; D018915:Root Canal Preparation / Q000379:methods; D012965:Sodium Chloride / Q000737:chemistry; D012997:Solvents / Q000737:chemistry*; D013314:Stress, Mechanical; D013997:Time Factors
chemical_list: D000891:Anti-Infective Agents, Local; D003188:Composite Resins; D017220:Dentin-Bonding Agents; D010756:Phosphoric Acids; D011109:Polymethacrylic Acids; C462240:RelyX ARC; D019279:Resin Cements; D012388:Root Canal Irrigants; C084018:Scotchbond Multi-Purpose; D012997:Solvents; D000431:Ethanol; D011092:Polyethylene Glycols; D012965:Sodium Chloride; D017438:Bisphenol A-Glycidyl Methacrylate; C030242:phosphoric acid; D002710:Chlorhexidine