Bonding agents have hydrophilic and hydrophobic groups. The hydrophobic group binds which structure?
(A) Calcium in enamel (B) Hydroxyapatite group in hard tissue (C) Resin in restoration (D) Collagen in dentin
(C) Ideally, a dentin bonding agent should have both hydrophilic and hydrophobic ends. The hydrophilic end displaces the dentinal fluid to wet the surface. The hydrophobic end bonds to the composite resin.
Bonding: The forces or energies between atoms or molecules at an interface that hold two phases together.
Mechanism of bonding:
Dentin adhesive molecule has a bifunctional structure:
M-R-X
Where,
M is the double bond of methacrylate which copolymerizes with composite resin.
R is the spacer which makes the molecule large.
X is a functional group for bonding, which bonds to an inorganic or organic portion of dentin.
Ref: Textbook of Operative Dentistry, Nisha and Amit Garg, 3rd edition, Pg no:239