title: Effect of calcium hydroxide and endodontic irrigants on fibre post bond strength to root canal dentine.
abstract: OBJECTIVE
  To analyse the effect of calcium hydroxide paste, endodontic irrigants and time of application on the bond strength of fibre posts to root canal dentine.
  
  
  METHODS
  Seventy bovine incisors were divided into 7 groups according to removal of calcium hydroxide and distilled water (CHW) (immediate - I; 21 days - 21 days; 6 months - 6 months) and endodontic irrigant (1% sodium hypochlorite - SH; 1% sodium hypochlorite + 17% EDTA - SHE). Fibre posts were cemented (RelyX U100), after which the roots were serially sectioned and submitted to a micro-push-out test. Data were analysed using two-way anova followed by the Tukey's and the Dunnett's tests (α = 0.05).
  
  
  RESULTS
  The CHW groups were not significantly different from the control group in 13 of the 18 associated factors (P > 0.05). There were significant reductions in bond strength in the cervical (P = 0.0216) and middle (P = 0.0017) thirds of the root at 6 months in groups irrigated with SH. Irrigation with SHE reduced the bond strength significantly in the middle (P = 0.0488) and apical (P = 0.0252) thirds of the roots in the immediate groups and in the middle third (P = 0.0287) in the 21-day group. Bond strength was greater in the cervical than in the apical thirds of all immediate and 21-day groups (P < 0.05).
  
  
  CONCLUSIONS
  Bond strength of groups that received CH paste was similar to that found in the control group in 13 of the 18 associated factors. EDTA and SH reduced bond strength in specimens in the immediate (middle and apical thirds) and 21-day (middle third) groups. There was a significant reduction in bond strength in the groups irrigated with SH and tested at 6 months (cervical and middle thirds). There was a predominance of adhesive failures between resin cement and dentine in all groups.
authors.affiliation: Department of Operative Dentistry, Federal University of Uberlândia, Uberlândia, MG, Brazil.
authors.forename: S R
authors.initials: SR
authors.lastname: Renovato
authors.forename: F R
authors.initials: FR
authors.lastname: Santana
authors.forename: J M
authors.initials: JM
authors.lastname: Ferreira
authors.forename: J B
authors.initials: JB
authors.lastname: Souza
authors.forename: C J
authors.initials: CJ
authors.lastname: Soares
authors.forename: C
authors.initials: C
authors.lastname: Estrela
mesh_terms: D000268:Adhesiveness; D000818:Animals; D002126:Calcium Hydroxide / Q000737:chemistry*; D002417:Cattle; D002484:Cementation / Q000379:methods; D001840:Dental Bonding; D003786:Dental Pulp Cavity / Q000648:ultrastructure*; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000648:ultrastructure*; D004492:Edetic Acid / Q000737:chemistry; D055115:Light-Curing of Dental Adhesives / Q000379:methods; 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 / Q000295:instrumentation / Q000379:methods; D012973:Sodium Hypochlorite / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D019227:Tooth Apex / Q000648:ultrastructure; D019237:Tooth Cervix / Q000648:ultrastructure; D014867:Water / Q000737:chemistry
chemical_list: D019279:Resin Cements; D012388:Root Canal Irrigants; D014867:Water; D004492:Edetic Acid; D012973:Sodium Hypochlorite; D002126:Calcium Hydroxide
keywords: bond strength; calcium hydroxide; endodontic irrigant; fibre post