This document discusses the challenges of dentin bonding and the evolution of dentin bonding agents. It addresses the following key points: - Dentin is a highly permeable tissue with dentinal tubules that make bonding challenging. - Early bonding agents from generations I-III showed bond strengths from 2-15 MPa but bonding decreased over time as resin did not penetrate smear layers well. - Generation IV agents introduced acid etching to open tubules followed by a primer and bonding agent, increasing bond strengths to 20-28 MPa. - Current self-etching agents from generations V-VII are more user-friendly as a single bottle or step but may compromise enamel margins. Hybrid layer formation

2. MEN WILL BE MEN……

4. DENTIN ADHESION

5. Mineral
Water
Oraganic
50%
25%
25%

7. CHALLENGES IN DENTIN
BONDING
• Dentin -highly permeable tissue
• Diameter of tubules - Pulp=2.5u
DEJ =0.8u
• No. of tubules
pulp = 45,000/Sq.mm
dej = 20,000/Sq.mm

8. • Dentin is intrinsically hydrated tissue
• Dentinal fluid is under outward pressure
• Age changes-sclerosis and reparative dentin
• RDT-bond strength decreases with depth

9. SMEAR LAYER
solid phase: denatured collagen
liquid phase: fluid filled channels

10. Barrier to the penetration of resin , multiplication of bacteria
Barrier against bacterial & toxin penetration

11. Acid etched dentin
• Opens the dentin tubules
• Intertubular collagen exposed

12. Mechanism of dentin
bonding
M- R- X
M- Methacrylate group
R- spacer
X- Reactive group; bonds to dentin

15. E P B

17. Evolution
I generation
• NPG GMA- Primer
• Chelating action with surface dentin
• Bond strength – 2.8 Mpa
Ex: Cervident (SS White)

18. II Gen DBA
• Phosphate esters of BisGMA or HEMA
• Smear layer weakest link
• Ex: Clearfil F(Kuraray)
Scotch Bond
Prisma Universal
• Bond strength – 2-7 Mpa

19. III Gen DBA
• Modify or remove smear layer
• Conditioning & priming
• Bond strength= 9-15 Mpa
• I system- FNP ,Tenure
Scotch Bond -2

20. • Retention decreases with time
• Resin did not penetrate the smear layer

21. IV Gen DBA
• Based on acid etched dentin
1. an acid etching gel
2. primer
3. bonding agent
E P B

22. • Ex: All bond -2(21.4 MPa)
• Scotch bond Multipurpose (21 MPa)
• Clearfil Liner bond 2 (kuraray)- 20-28 MPa

23. V Gen Bonding agents
• Hybridization & Wet bonding technique
• One component resin (Priming + bonding)
• Ex:
Prime & Bond ,Prime & Bond 2.1
• 20 MPa
E P B

24. Advantages
• Bond strength sufficient
• Some agents incorporate Fluoride
• Time saving
Disadvantage
• Solution must be refreshed

25. VI Gen Bonding agents-
SE
TYPE I
• SE Primer & Adhesive
• Primer applied to tooth
followed by adhesive.
Ex: Clearfil SE
Nano Bond
Optibond
Prompt L Pop
TYPE II
• Primer & Self-
etching adhesive
• Mixed & applied.
• Ex: Xeno III

26. B
E P
E
P B

27. VII Gen bonding
agents
• Modification of type II Sixth gen
• Single bottle containing acidic adhesive
• Solvent-water
• Ex: G-Bond , i-Bond, Clearfil S3
E P B

28. Self etching primers
• Introduced in Japan
• Phosphonated resin molecule
Priming
• No rinsing & drying steps
• Less variation in degree of substrate moisture
Etching

29. • Advantage
Less technique sensitive
Demineralize and infiltrate simultaneously
Less Post Op. sensitivity
• Disadvantage
do not etch the enamel
seal at enamel margins compromised

30. SEP’s classified into 3 categories:
1. Strong : Ph of 1 or below
2. Mild-SE systems: Ph of around 2
3. Intermediary strong : Ph is about 1.5

32. HYBRID LAYER