Compromised bond strength after root dentin deproteinization reversed with ascorbic acid.
BACKGROUND
The present study evaluated the effect of a reducing agent on the bond strength of deproteinized root canal dentin surfaces when using a self-adhesive versus dual-cured cement. Regional differences were also evaluated.


METHODS
A total of 45 bovine incisor roots were divided into 3 groups: irrigation with physiologic solution (control), 10-minute deproteinization with 5% NaOCl, and 10-minute deproteinization with 5% NaOCl followed by 10 minutes of 10% ascorbic acid. Fiber posts were cemented with either RelyX U100 or RelyX ARC (with SingleBond 2 or Clearfil SE Bond). The push-out bond strength was evaluated after 24 hours of storage. Data were submitted to three-way analyses of variance and Dunnett T3 tests (alpha = 0.05).


RESULTS
No differences between cements were observed within the testing conditions, regardless of the adhesive (P < .05). Deproteinization reduced bond strengths. Subsequent treatment with ascorbic acid was capable of reversing bond strength value changes to levels similar to those of controls. Regional radicular differences were also found, where coronal > middle > apical.


CONCLUSIONS
The reducing agent was capable of reversing the effect of dentin deproteinization, and RelyX U100 behaved similarly to RelyX ARC.
da Cunha
Leonardo Fernandes
LF
Department of Operative Dentistry, Endodontics, and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil. cunha_leo@yahoo.com.br
Furuse
Adilson Yoshio
AY
Mondelli
Rafael Francisco Lia
RF
Mondelli
José
J
D000134:Acid Etching, Dental / Q000379:methods*; D000818:Animals; D001205:Ascorbic Acid / Q000737:chemistry / Q000494:pharmacology; D002417:Cattle; D001840:Dental Bonding; D003799:Dental Stress Analysis; D003804:Dentin / Q000737:chemistry / Q000187:drug effects*; D010084:Oxidation-Reduction; D011176:Post and Core Technique; D011506:Proteins / Q000187:drug effects; D019279:Resin Cements; D012388:Root Canal Irrigants / Q000009:adverse effects; D033081:Shear Strength; D012973:Sodium Hypochlorite / Q000009:adverse effects; D014092:Tooth Root
D011506:Proteins; D019279:Resin Cements; D012388:Root Canal Irrigants; D012973:Sodium Hypochlorite; D001205:Ascorbic Acid