adhesion

2. ADHESION

3. CONTENTS
INTRODUCTION
HISTORY
MECHANISM OF ADHESION
ADHESION TO ENAMEL
ADHESION TO DENTIN
DENTAL ADHESIVE SYSTEM
CLASSIFICATION OF DENTIN BONDING
AGENTS
CONTROVERSIES IN BONDING
CONCLUSION

4. INTRODUCTION
 Adhesion is defined as “the state in which two surfaces are held together by
interfacial forces which may consist of valence forces or interlocking forces or
both.”
 The word adhesion comes from the Latin word adhaerere(“to stick to”).
 An adhesive is a material, frequently a viscous fluid, that joins two substrates
together and solidifies and is able to transfer a load from one surface to the other.
Sturdvent’s art and science of operative dentistry 6th edition

5.  Dental adhesives are solutions of resin monomers that make the resin dental
substrate interaction achievable.
Perdigão J. New developments in dental adhesion. Dent Clin North Am. 2007;51:333–357
 Adhesive systems are composed of monomers with both hydrophilic groups and
hydrophobic groups.
 The hydrophillic groups enhance wettability to the dental hard tissues, while the
hydrophobic groups allow the interaction and co-polymerization with the
restorative material.
Van Landuyt KL, Snauwaert J, De munck J, Peumans M, Yoshida Y, Poitevin A, et al. Systematic
review of the chemical composition of contemporary dental adhesives. Biomaterials. 2007;28:3757–3785

6. HISTORY AND EVOLUTION OF
DENTAL ADHESIVES

7. -
1955’s - Buonocore proposed dental adhesive
technology
1956’s first generation adhesives were introduced
Mid 1960’s proposed bonding of dentin with
commercially available pit and fissure sealants and
composite resin utilizing bonding
Late 1960’s proposed bonding of dentin
1970’s the beginning of both concept of ‘Total
Etch’ and ‘Smear Layer’
Late 1970’s second generation

8. Early 1980’s widespread acceptability of etch
and rinse adhesives
1980’s third generation
1990’s acceptance of ‘The Hybrid Layer ’,concept of
availability of multi step, single-step adhesive and ‘The
Concept of Wet Bonding’
Early 1990’s fourth generation
Mid 1990’s fifth generation

9. Late 1990’s The Concept of Smear Layer
Modification : self-etch adhesives develop from
first and second generation
Late 1990’s and early 2000’s sixth generation
Late 2002’s and early 2005’s seventh generation
2010’s eight generation
2011’s universal adhesives

10. MECHANISM OF ADHESION
Mechanical adhesion: Interlocking of adhesive with irregularities
in the surface of the substrate or adherend.
Adsorption adhesion: The forces (Chemical bonds) involved may
be primary (ionic & covalent) or secondary (hydrogen bonds, dipole
interaction, or Vander waals valence forces).
Diffusion adhesion: Interlocking between mobile molecules, such
as the adhesion of two polymers through diffusion of polymer chain
ends across an interface.
Electrostatic diffusion: An electrical double layer at the interface
of a metal with a polymer that is part of the total bonding
mechanism.

11.  1. Mechanical—penetration of resin and formation of resin tags within the
tooth surface
 2. Adsorption—chemical bonding to the inorganic component
(hydroxyapatite) or organic components (mainly type I collagen) of tooth
structure
 3. Diffusion—precipitation of substances on the tooth surfaces to which
resin monomers can bond mechanically or chemically
 4. A combination of the previous three mechanisms
MECHANISM OF BONDING OF
RESINS TO TOOTH STRUCTURE