Mild acids are known to activate dentin matrix metalloproteinase (MMPs). All self‐etching dental adhesives are acidic (pH 1.5–2.7) and may activate dentin MMPs. The purpose of this study was to compare the ability of several all‐in‐one adhesives to activate gelatinolytic and collagenolytic activities in powdered mineralized dentin. Powdered dentin made from human teeth was mixed with all‐in‐one adhesives (Clearfil Tri‐S Bond, G‐Bond, Adper Prompt L‐Pop) or a self‐etching primer (Clearfil SE Bond primer) for varying times and then the reaction was stopped by extracting the adhesives using acetone. Fresh untreated mineralized dentin powder had a gelatinolytic activity of 3.31 ± 0.39 relative fluorescent units (RFU) per mg dry weight (24 h) that increased, over storage time, to 87.5 RFU mg −1 (24 h) after 6–8 wk. When fresh powder was treated with acidic Tri‐S Bond, the gelatinolytic activity increased from 3.24 ± 0.70 RFU mg −1 to &gt; 112.5 RFU mg −1 (24 h) after 20 min and then remained unchanged. Monomers with lower pH values produced less activity. There was a significant, direct correlation between gelatinolytic activity and pH, with Tri‐S giving the highest activity. Coating dentin powder with Tri‐S resin prevented fluorescent substrates from gaining access to the enzyme, even though it activated the enzyme. In conclusion, self‐etch adhesives may activate latent MMP and increase the activity to near‐maximum levels and contribute to the degradation of resin–dentin bonds over time.

Activation of gelatinolytic/collagenolytic activity in dentin by self‐etching adhesives