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
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
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
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
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