Effect of MTAD on the shear bond strength of self-etch adhesives to dentin

Abstract

Background: As the use of different irrigants to eliminate residual debris and smear layer in
the field of endodontic is unavoidable, by considering the effect of irrigants on the bond strength
of resin composite restorations, this study was designed to evaluate the effect of a mixture of a
tetracycline isomer, an acid, and a detergent (MTAD) on the shear bond strength of two self-etch
adhesives, Clearfil SE Bond and Adper Prompt L- Pop to dentin.
Materials and Methods: The crowns of 80 extracted premolars were transversally sectioned to
expose dentin. Flat dentin surfaces were wet abraded with 320-grit abrasive paper and randomly
assigned to eight groups according to two self-etch adhesive and four dentin surface treatments:
direct application over smear layer (no treatment), etching with 35% phosphoric acid for 15s, 1
min 5.25% NaOCl/1 min MTAD and 20min 1.3% NaOCl/5min MTAD. Shear bond strength was
tested 24 h after storage in distilled water at 37ºC in incubator. Data were analyzed using one-way
ANOVA followed by duncan post-hoc (α=0.05).
Results: Phosphoric acid etching prior to SE Bond application significantly decreased the shear bond
strength to dentin (P<0.05). Application of MTAD clinical protocol (20min 1.3% NaOCl/5min MTAD)
did not significantly decrease the shear bond strength of self-etch adhesives to dentin (P=0.745)
Conclusions: Based on the results of present investigation, it seems that the use of clinical protocol
of 1.3% NaOCl as a root canal irrigant and a 5-min application of MTAD as a final rinse to remove
the smear layer has no adverse effect on the shear bond strength of self-etch adhesives to dentin.
Key Words: Adhesives, bond strength, smear layer, MTAD