Osorio R, Yamauti M, Osorio E, Román JS, Toledano M. Zinc‐doped dentin adhesive for collagen protection at the hybrid layer.
Eur J Oral Sci 2011; 119: 401–410. © 2011 Eur J Oral Sci
The aim of the study was to ascertain whether the addition of zinc to adhesives may decrease metalloproteinase‐mediated collagen degradation without affecting bonding efficacy. Human dentin beams were treated with phosphoric acid, with Clearfil SE Bond Primer or with Clearfil SE Bond Primer plus ZnCl2 (2 wt%). Acid‐etched dentin was infiltrated with Single Bond, Single Bond plus ZnCl2 (2 wt%), or Single Bond plus ZnO nanoparticles (10 wt%), and Clearfil SE Bond‐primed dentin was infiltrated with Clearfil SE Bonding resin, Clearfil SE‐Bonding resin with ZnCl2 (2 wt%), or Clearfil SE‐Bonding resin with ZnO nanoparticles (10 wt%). The C‐terminal telopeptide concentrations were determined 24 h, and 1 and 4 wk after treatment. Microtensile bond strength to dentin was determined for the tested adhesives. Matrix metalloproteinases‐mediated collagen degradation occurred in acid‐etched and SE‐primed dentin. Resin infiltration decreased collagen degradation. Lower collagen degradation was found for SE Bond than for Single Bond. Zinc‐doped Single Bond resin always reduced collagen degradation, the ZnO particles being more effective than ZnCl2. Zinc‐doped SE Bond reduced the liberation of C‐terminal telopeptide only at 24 h. Bond strength to dentin was not decreased when Zn‐doped resins were employed, except when ZnCl2 was added to SE Primer. Zinc‐doped resin reduced collagen degradation in Single Bond hybrid layers, but did not affect bond strength. The addition of zinc to SE Bond had no beneficial effects.