Does acid-etching jeopardize dentin bonding durability?

Purpose: The purpose of the study was to evaluate the impact of the etching process on the durability of normal versus sclerotic dentin bonded interfaces.
Materials & Methods: Micro-tensile bond strengths and interfacial nanoleakage, within bonded normal or sclerotic dentin interfaces created by Adper Single Bond 2, Optibond XTR, Single Bond Universal, Ketac Molar (glass ionomer) or Photac Fil (resin-modified glass ionomer), were evaluated after 24 h, 6 m and 12 m of water storage.
Results: Adper Single Bond 2, Optibond XTR and Single Bond Universal exhibited higher immediate bond strengths and nanoleakage than did Ketac Molar or Photac fil. Normal dentin exhibited higher immediate bond strength and lower immediate nanoleakage when compared to sclerotic dentin, using Adper Single Bond 2, Optibond XTR and Single Bond Universal. Twelve months of water storage resulted in a significant decrease in micro-tensile bond strength in both normal and sclerotic dentin bonded by these three adhesives. However, there was no significance difference between the bond strengths and nanoleakage created by Ketac Molar and Photac Fil, used with normal or sclerotic dentin at the three storage periods.
Conclusion: Compared to resin-based etching restoratives, mineral-based non-etching restoratives (Ketac Molar and Photac Fil) provided much more durable bonds, to both normal and sclerotic dentin, over a period of 12 months. It is obvious that the acid-etching procedure is the main cause of instability of resin-dentin bonded interfaces. Sclerotic dentin did not act as a bonding impediment with mineral-based non-etching restoratives as it did with resin-based etching adhesives.
Clinical Significance: Although recently introduced adhesive resins have attempted to improve resin-dentin bond durability, biodegradation of resin-dentin bonds over time continues to jeopardize the durability of resin composite restorations.