title: Effects of potassium oxalate on knoop hardness of etch-and-rinse adhesives.
abstract: The objective of this study was to determine whether the hardness of etch-and-rinse adhesives may be affected by the pretreatment of acid-etched dentin with potassium oxalate desensitizer. Unerupted human third molars were cut into crown segments by removing the occlusal enamel and roots. The pulp chamber of these crown segments was connected to a syringe barrel filled with phosphate-buffered saline so that the moisture of dentin was maintained during the bonding procedures. Three etch-and-rinse adhesives-two two-step systems (Adper Single Bond 2 [SB], One-Step [OS]) and one three-step system (Adper Scotchbond Multi-Purpose [MP])-were applied to acid-etched dentin that had been treated (experimental groups) or not (control groups) with potassium oxalate (BisBlock). The Knoop hardness (KHN) of adhesives was taken at different sites of the outer surface of the adhesive-bonded dentin. The KHN of the three tested adhesives applied to acid-etched dentin treated with potassium oxalate was significantly lower than that exhibited by the respective controls (not treated with oxalate; p<0.05). Regardless of the adhesive, the treatment with potassium oxalate reduced the adhesives' KHN (p<0.05), with the OS system exhibiting the lowest KHN compared with the MP and SB systems.
authors.affiliation: University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: S M A
authors.initials: SM
authors.lastname: Silva
authors.forename: J
authors.initials: J
authors.lastname: Malacarne-Zanon
authors.forename: R M
authors.initials: RM
authors.lastname: Carvalho
authors.forename: M C
authors.initials: MC
authors.lastname: Alves
authors.forename: M F
authors.initials: MF
authors.lastname: De Goes
authors.forename: A
authors.initials: A
authors.lastname: Anido-Anido
authors.forename: M R
authors.initials: MR
authors.lastname: Carrilho
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D003738:Dental Cements / Q000737:chemistry; D057133:Dentin Desensitizing Agents / Q000737:chemistry*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006244:Hardness; D006801:Humans; D055115:Light-Curing of Dental Adhesives; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D010070:Oxalates / Q000737:chemistry*; D019815:Oxalic Acid / Q000737:chemistry; D010756:Phosphoric Acids / Q000737:chemistry; D058105:Polymerization; D019279:Resin Cements / Q000737:chemistry; D013499:Surface Properties
chemical_list: C554641:Adper single bond 2; C103506:Bis-GMA, BPDM, HEMA dental-bonding resin; C514542:BisBlock; D003738:Dental Cements; D057133:Dentin Desensitizing Agents; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D010070:Oxalates; D010756:Phosphoric Acids; D019279:Resin Cements; C084018:Scotchbond Multi-Purpose; D019815:Oxalic Acid; C030242:phosphoric acid