title: Immediate shear bond strength of resin cements to sodium hypochlorite-treated dentin.
abstract: BACKGROUND
  The purpose of this in vitro study was to evaluate the immediate shear bond strength of different categories of resin cements on sodium hypochlorite (NaOCl)-treated dentin and to evaluate if the bond was improved by a subsequent treatment with 10% sodium ascorbate before adhesive procedures.
  
  
  METHODS
  This study tested immediate shear bond strengths to human dentin of 5 resin cements: Variolink II (Ivoclar Vivadent, Schaan, Liechtenstein), Multilink (Ivoclar Vivadent), Clearfil Esthetic Cement EX (Kuraray, Tokyo, Japan), SpeedCEM (Ivoclar Vivadent), and Clearfil SA Cement (Kuraray). All cements were tested with no NaOCl pretreatment of the dentin (negative control) and with a 20-minute exposure of the dentin to 6% NaOCl before bonding procedures. The cements found to have decreased bond strengths to NaOCl-treated dentin were tested with the dentin exposed to 10% sodium ascorbate after NaOCl exposure. The sodium ascorbate exposure times tested were 5 seconds and 1 minute.
  
  
  RESULTS
  The mean and standard deviation values for immediate shear bond strength (MPa) for the negative control group were as follows: Variolink II, 18.8 ± 4.2; Multilink, 29.1 ± 7.1; Clearfil Esthetic Cement EX, 20.7 ± 4.9; SpeedCEM, 17.8 ± 4.2; and Clearfil SA Cement, 7.2 ± 2.8. The results for the NaOCl exposure group were as follows: Variolink II, 24.0 ± 6.7; Multilink, 34.1 ± 6.1; Clearfil Esthetic Cement EX, 20.7 ± 6.8; SpeedCEM, 0.0 ± 0.0; and Clearfil SA Cement, 0.1 ± 0.1. The results for the 5-second sodium ascorbate group were the following: SpeedCEM, 8.5 ± 2.6, and Clearfil SA Cement, 4.3 ± 2.0. The following results were found for the 1-minute sodium ascorbate group: SpeedCEM, 12.2 ± 3.2, and Clearfil SA Cement, 4.8 ± 1.0.
  
  
  CONCLUSIONS
  The resin cements tested varied in their capacity to adhere to NaOCl-treated dentin. Some resin cements exhibited equal or improved bond strengths (P < .05), whereas others exhibited significantly decreased bond strengths (P < .05). For the susceptible resin cements, a rinse of 10% sodium ascorbate provided an immediate restoration of at least 50% of the original bond strength (P < .05). The efficacy of sodium ascorbate may vary among resin cements.
authors.affiliation: Private Practice, Tulsa, Oklahoma. Electronic address: cdsdds@sbcglobal.net.
authors.forename: Clinton D
authors.initials: CD
authors.lastname: Stevens
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000268:Adhesiveness; D000975:Antioxidants / Q000737:chemistry; D001205:Ascorbic Acid / Q000737:chemistry; D001840:Dental Bonding; D003786:Dental Pulp Cavity / Q000648:ultrastructure*; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D010756:Phosphoric Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry*; D033081:Shear Strength; D012973:Sodium Hypochlorite / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors
chemical_list: D000975:Antioxidants; C581302:Clearfil SA; D017220:Dentin-Bonding Agents; D010756:Phosphoric Acids; D019279:Resin Cements; C530542:clearfil esthetic cement; C502351:multilink adhesive system; C103502:Variolink; D012973:Sodium Hypochlorite; C030242:phosphoric acid; D001205:Ascorbic Acid
keywords: Ascorbic acid; dentin bonding; resin cements; root canal irrigants; shear strength; sodium hypochlorite