Question Asked on 4/30/2014

The all-in-one adhesive that can be used for everything: does it exist?

Answer Response by Dr. Suh on 4/29/2014

Yes, the new “universal” category of adhesives (not to be confused with previous 7th Generation All-in-One adhesives) can be used for everything, including:

  • Hydrophobic enough to be used as a single-layer adhesive.
  • Any etching technique: total-etch, self- etch, or selective-etch modes.
  • Both direct and indirect clinical procedures using light-cure, dual-cure, or self-cure materials (without the need for a separate self-cure activator).
  • Can bond to indirect substrates (low film thickness < 10 µm).

However, not all new “universal” adhesives are created equal. Some are more hydrophobic (optimized water content), or require a 2nd hydrophobic resin layer. Also, some require a separate self-cure activator in order to be used with dual-cure/self-cure restorative materials.  In addition, some contain silane, claiming to be effective as a coupling agent, but research has shown that silane is not effective because Bis-GMA and other resins in the formula inhibit the condensation reaction. The condensation reaction occurs between the silanol (-Si-OH-) and ceramic substrate’s –OH group, slowly liberating water molecules to form stable siloxane (-Si-O-Si-) bonds. The liberation of water molecules is essential for the condensation reaction to continue, which can be inhibited by the presence of extra resin, which slows water evaporation (Le Chatelier’s principle).


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