Dentin Bonding agents

© Ramaiah University of Applied Sciences
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Faculty of Dental Sciences
Presented by : Dr.Arbiya Anjum S
Dentin Bonding Systems Bonding
agent

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Contents
• Introduction
• History
• Adhesion
• Classification
• Acid etching
• Enamel etching
• Enamel etching patterns
• Etchants
• Hybridization layer
• Criteria for bonding system
• Problems faced in bonding to dentin
• Components
• Conditioning
• Primers
• Mechanism of action of DBA
• Solvents used in primers
• Wet/Moist bonding
• Over-wetting phenomenon
• Dry bonding
• Hybrid layer
• Fillers
• Water trees effect
• Chronological classification
• Total etch adhesives
• 3-step and 2-step total etch adhesive
• Self-etch adhesives
• 2-step and 1-step self etch primer
• Amalgam bonding
• Ceramic bonding
• Failures in bonding
• Literature review
• Conclusion
• References

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Faculty of Dental Sciences©M. S. Ramaiah University of Applied Sciences
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Introduction
Retention of restoration
Conservation of tooth structure
Elimination of marginal microleakage
Reinforcement of remaining tooth structure
Increasing the clinical life time of restorations
Extension For Prevention Minimal Invasion

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HISTORY
1955-Buonocore
developed acid
etching with
phosphoric acid
1957 - Bowen gave
BISGMA resin system
1965 - Causton
described how primer
works
1975 - Gwinnet and
Silverstone described 3
paterns of etching of
enamel

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1982-Fusayama-
concept of total etching
and bonding
1990s -Kanca- concept
of wet bonding
1997- 2003 -Ferrari et al -
Development of one bottle
bonding systems.Sixth and
Seventh generation bonding
systems

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Adhesion
ADHESIVE
ADHEREND
ADHESIVE
STRENGHTH
• Adhesion is derived from the Latin (adhaerere) meaning “a state in which two surfaces
are held together by interfacial forces like valence forces or interlocking forces or both” (The
American society for testing materials)
• Adhesive - Substance that promotes adhesion of one substance or material to another
• Adherend - A material substrate that is bonded to another material by means of an
adhesive

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Classification
Theories :
1. Mechanical –interlocking of adhesive with irregularities in the surface of the substrate
2. Adsorption –chemical bonding between adhesive and the adherent, forces involved are
primary(ionic and covalent) or secondary (Van derWaals forces, hydrogen bonds)
3.Diffusion – interlocking between mobile molecules, such as the adhesion of two polymers
through diffusion
4.Electrostatic – an electrical double layer at the interface of a metal with a polymer making
a certain/obscure contribution to the bond strength

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Factors Affecting Adhesion
• Wetting : Wetting is the ability of the liquid to flow easily over the entire surface and adhere to the
solid
• If the adhesive does not wet the surface of the adherend, adhesion between the adhesive and
adherend will be negligible or nonexistent

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Surface Energy
• The surface tension of the liquid and the surface energy of the adherend, ultimately
determine the degree of wetting that occurs
• Generally, the harder the surface , the higher the surface energy will be, which means that
adhesive properties of the material will be higher
• Hydroxyapatite(High surface energy);Collagen(low energy surfaces)

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• Acid etching : It is the process of increasing the surface reactivity by demineralizing the
superficial calcium layer and thus creating the enamel tags. These tags are responsible for
micromechanical bonding between tooth and restorative resin

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Compositional & structural aspects of enamel & dentin
• The inorganic content of mature enamel is 95%by wt% & 86% by vol%; the primary
component is hydroxyapatite
• The remainder consists of water & organic material
• Unlike enamel, dentin contains higher % of water and organic material(type I collagen) &70
wt % of hydroxyapatite
Mjor IA, Fegerskov o, eds. Human oral embryology & histology,1986

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• Numerous dentinal tubules radiate from pulp through out the entire thickness of
dentin(fan shaped), making dentin highly permeable tissue
• 96% superficial dentin surface is composed of intertubular dentin; only 1% is occupied by
fluid in the dentinal tubules & 3 % by peritubular dentin
• Near pulp peritubular dentin 66% & intertubular dentin only 12 %, while rest 22% by watar
. Hence, dentin is an intrinsically wet tissue
Garberoglio R, Brannstrom M, Arch Oral Biol, 1976

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Problems in bonding to dentin
1) Presence of 25% organic material and 25% fluid in dentin
2) Random arrangement of hydroxyapatite crystals in the organic matrix
3) Tubular nature of dentin that permits fluid flow, adversely affects bonding
4) Sclerosed dentin is difficult to penetrate
5) Presence of smear layer complicates bonding
6) Permeability of dentin differs at various sites
7) Variation in arrangement of tubules & their shape

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Depth, location, and tubule orientation:
• Density of dentinal tubules - 20,000 to 50,000 tubules per square millimetre, at a level 2mm from the pulp it is
30,000 tubules per square millimetre with diameter of 1.1 microns
• Density is more towards pulp because tubules are radically concentric to pulp and tubules near pulp are less
narrow due to peritubular mineralization
• Water content of dentin is more towards pulp and diminishes significantly towards dentin–enamel junction
(DEJ)
• Suzuk et al;2000 - bond strengths in deep dentin are around 30–50% lower than in superficial dentin

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Enamel Etching
• Enamel adhesion-micromechanical retention
Resin tags
• Macrotags: -Form between the enamel rod
peripheries
- 2-5 Microns
• Microtags - Across the end of each rod where
hydroxyapatite crystals have been dissolved
• Bond strength to acid conditioned enamel :16 – 21
M Pa
Van Meerbeek & Others: Adhesion to Enamel and Dentin

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Enamel Etching Patterns
• Type 1 – Most common. Preferential removal of enamel prism cores & periphery intact
• Type 2 - Reverse of type 1. Periphery removed and cores intact
• Type 3 – Etching pattern less distinct. Both types 1 & 2 present Gwinnett AJ and Silverstone 1974

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Etchants
1. Phosphoric acid – as liquid or gel
• Conc 30 – 40 % - for 15 sec - ideal. (Silverstone et al 1975)
• Conc more than 50 % - monocalcium phosphate monohydrate precipitate
• Conc less than 30% - dicalcium phosphate dihydrate precipitate( cannot be easily
removed )
• Higher conc - deeper tags, break away easily
2. Sulphuric acid 2 %
3. Maleic acid 10 %
4. Nitric acid 2.5 %
5. Oxalic acid
6. Citric acid
• Depth of decalcification is affected by – pH of the acid ,Concentrations , Viscosity ,
Application of time of etchant

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Smear layer – Skinner 1961
• When a tooth structure is prepared with a bur or an instrument, residual organic and
inorganic components form a layer of debris on the surface of substrate which is termed
as Smear layer
• Thickness of the smear layer : 0.5 - 2µm
• Thickness of smear plug : 1-10 µmSmear Layer – inherently weak attachment to dentin and
dislodges easily (cohesive Failures) – to overcome this the
smear layer removal was advocated

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Ideal Characteristics of Dentin Bonding Agents
1. Bond to dentin with a strength equal to or greater than that of a composite resin bonded to etched enamel
2. Rapidly (within a few minutes) attain maximum bond strength to permit finishing and polishing procedures and
postoperative patient functioning within a reasonable time frame
3. Be biocompatible and nonirritating to the pulp
4. Prevent micro-leakage, recurrent caries and marginal staining
5. Exhibit long-term stability in the oral environment
6. Be easy to apply and clinically forgiving
7. Possess a good shelf life
8. Be compatible with a wide range of resins
9. System should not be toxic or sensitizing to the operators and patients
10. Should seal the tooth surface from oral fluids.
(Phillips and Rage, 1961)
CLINICAL USES OF DENTIN BONDING SYSTEMS:
1. Bonding of directly placed resin based restorative materials
2. Bonding of indirectly placed restorative materials
3. Bonding of ceramic restorations
4. Bonding of amalgam restorations
5. Bonding of prefabricated and cast posts
6. Bonding orthodontic brackets
7. Bonding periodontal splints
8. Repair existing restorations
9. Sealing of pits and fissures of posterior teeth
10. Treatment of cervical sensitive dentine
11. Reattachment of fractured tooth fragments
12. Pulp capping
13. Reinforce fragile roots internally
14. Seal apical restorations placed during endodontic surgery

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Components
• Conditioning (cleaning)
• Priming (wetting, adapting)
• Bonding (mechanical adhesion, curing)

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Conditioning
“Alteration done after the creation of dentin cutting debris(smear layer), to create a surface,
capable of micromechanical and chemical bonding to dentin bonding agent”
Can be done by -
Chemicals ( Acids, Calcium chelators )
Thermal (lasers)
Mechanical (abrasion)
• Maleic acid: 10%
- Removes only smear layer, not plugs
- Hybrid layer formed is thin.
• Polyacrylic acid:
- 40% solution is used
- A 10 second application opens up the dentinal tubules but does not effect pulp as the
particle size is greater than diameter of dentinal tubules

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• Phosphoric acid : First dentin conditioner
37% H3PO4 is used
• Nitric acid : - Stronger than H3PO4
- Concentration of 2.5%
• Citric acid :
- 10% citric acid is recommended
- 10% citric acid + 3% ferric chloride was recommended by Nakabayashi
- Kurray proposed a combination of 10% citric acid and 20% CaCl2 to stabilize collagen during
etching
• Pyruvic acid: - Pyruvic acid buffered with glycine is used to facilitate polymerization reactions
and adjust the pH
• Hydrochloric acid : Causes violent surface reactions
• Sulphuric acid 2 % for 30 sec , As effective as phosphoric acid

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Calcium chelators
To remove the smear layer without significant physical changes to the underlying substrate
as opposed to strong acid etchants
• EDTA:
- Commercially available as “Tublicid”
- It contains 0.1% EDTA and 0.15% Benzalkonium chloride
- Removes smear layer, not plugs
- It is scrubbed on the surface of the smear layer for a few seconds, then left passively
for another 60 seconds followed by additional scrubbing
Removes small amount of Ca, thus causing fall in the bond strength

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• Thermal conditioners:
- Lasers: Nd:YAG laser used at 10 to 30 pulses per second
- The mechanism of action is through microscopic explosions
• Laser causes
- Desensitization of dentin
- Decrease microorganisms
- Creates micromechanical retention
• Mechanical conditioners:
- Abrasion:Al2O3 is used for micro abrasion
0.5 μ particles are used

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Primers
• HEMA: 2-HydroxyethylMethacrylate
• PENTA: Dipenta Erythritol PentaAcrylate Monophosphate
• NPG-GMA: N- Phenyl Glycine Glucidyl Metharylate
Agents that promote wetting of the dentin with the bonding agent and increase the
penetration of the bonding agent into the dentin
• Surface tension - less than the surface free energy of the acid etched dentin
• Solvent- water or water miscible
• Monomer - hydrophilic because they must compete with water and diffuse through water
in the depths of demineralized zone

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Mechanism of action of bonding agents
• Hydrophilic part: (X)
Displaces water & wets the surface. Permits penetration into porosities of dentin.
Reacts with organic and inorganic portions ( phosphate esters Or carboxylic acid groups
) Capable of bonding to dentin
• Hydrophobic part: (M)
Reacts with the restorative resin which is hydrophobic
Usually made of Methacrylate group.
• R- Spacer
Is responsible for making the molecule large enough to keep methacrylate groups
spatially located for optimal chemical reaction with the composites
M R X

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Solvents used in Primers
Acetone based primers
Water chasing capacity
Evaporates quickly after being dispensed
Can evaporate from the container
Multiple coats may be required
Ethanol based primers
Evaporates less quickly
Less sensitive to wetness of dentin
Good surface energy and good penetration
Extra drying time
Water based primers
Slow evaporation
Not sensitive to wetness of dentin.
Replenish collapsed fibers
Long drying time
Water can interfere with adhesive if
not removed

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Wet bonding/ Moist bonding
• Refers to bonding in which acid etched dentin is moist and hence, acetone based
primers are used, which have water chasing capacity
• Azeotrophism:
In acetone containg primers, when acetone comes in contact with water, the boiling
point of acetone is raised &the boiling point of water is lowered causing evaporation of
both water and acetone and the resin is left behind
Dr. John Kanca and Gwinnet in 1992

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Overwetting Phenomenon
In total etch wet bonding technique
some areas of the cavity , pooling of too much water
solvent may diffuse into water
monomers undergo phase changes
blisters and globules
post operative sensitivity

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Dry Bonding
• Bonding in which the acid etched dentin is dry and
uses the adhesive systems that provide water based
primers
• These rehydrate and re-expand the collagen fibers ,
allowing the resin to infiltrate
• Rewetting by 35 % HEMA, chlohexidine

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Internal and external dentinal wetness
• Occlusal dentin is more permeable over the pulp horns than at the center of occlusal
surface; proximal dentin > occlusal dentin & coronal> root
Pashley DH, Pashley EL, Am J Dent, 1991
• The variability in dentin permeability makes dentin more difficult substrate for bonding
than enamel
Douglas WH, J Dent, 1989
Jacobsen & Soderholm showed that water interferes with the
polymerization of adhesives resulting in suboptimal conversion rates

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• Earlier dentin adhesives were too hydrophobic to be successful, recent adhesives tend to
be overly hydrophillic , also impairing adhesion
• Recently, the so called all-in-one adhesive have been reported to behave as
semipermeable membranes and to absorb moisture from “ the outside” as well as the
tooth itself Tay FR, J Adhes Dent, 2002
• This phenomena is due to highly hydrophilic nature of one-step self-etch adhesives.
Application of additional hydrophobic resin layer has shown to improve dentin seal
Tay FR, Pashley, J Can Dent, 2003

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Hybrid layer
• Resin reinforced zone, or resin infiltrated layer
• Structure formed in dental hard tissues by demineralisation of the surface and subsurface,
followed by infiltration of monomers and subsequent polymerisation
• Shag carpet appearance
- Appears when dentin surface after being acid etched is actively scrubbed with an acidic
primer solution
- The combined mechanical and chemical action of rubbing the acid etched dentin with an
acidic primer dissolves additional mineral salts while fluffing and separating the entangled
collagen at the surface

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Fillers
• Most of the bonding agents are unfilled
• May contain inorganic fillers 0. 5% to 40% by wt. microfillers, or nanofillers, and submicron glass.
• Advantages of nanofillers:
-Prevents nanoleakage
-Causes uniform thickness of adhesive layer
-Better flexibility to adhesives
-Better dissipation of forces
-Scatter of light is prevented
-Provides radio opacity

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Water Trees Effect
• Water can pass from dentin around resin tags & form water filled channels that project from
the hybrid layer into the overlying adhesives
• When these water filled channels are stained with silver, they often look like microscopic
trees
• These are called water trees by Tay & Pashley
• They suggested that they might act as potential sites for hydrolytic degradation of resin
&also may be the cause of nanoleakage
Am J Dent 2003 Feb;16(1):6-12

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Water tree phenomenon

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Chronological Classification
• First Generation -1965
• Agents used: NPG-GMA (Provided water
resistant bonds)
Cyanoacrylates
polyurethanes
• Mechanism of adhesion:
Chelation of NPG GMA with calcium on the
tooth surface to generate water resistant
chemical bonds of resin to dentinal calcium
• Bond strength : 2 – 3 MPa
Poor clinical results
Hydrolysis in oral environment.
Difficulty in bulk polymerization.
Low bond strength (2.1-2.8 MPa)
Hydrobhobic resin
Instability
Eg: Cervident

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Second Generation
• Early 1978
• Agents used:
- Phosphate ester material HEMA in ethanol
- Polyurethane based compounds
• Mechanism of action:
Surface wetting phenomenon and ionic
interaction between negatively charged
phosphate groups in the resin and positively
charged calcium in the smear layer
• Bond strength: 1- 5 Mpa
Low bond strength (1-3MPa)
Hydrolysis of phosphate - Ca++ bond.
Bonding obtained to the smear layer,
not to the dentin itself
Eg: Scotchbond dual cure
Clearfil
Bond lite
Prisma Universal Bond

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Third Generation-1984
• Negative effect of smear layer known by then. Thus
additional step of conditioning and priming to
remove smear layer
modify smear layer
• Mechanism of adhesion:
Conditioner removes smear layer and opens up the
tubule
Primer having both hydrophilic and hydrophobic
groups were used which facilitates bonding with the
adhesive
Increased bond strength
Improved clinical performance
Reduced microleakage relied on mechanical means
of bonding as opposed to the less reliable chemical
adhesion
Bond strength: 9-15 Mpa.
More number of steps, thus complex
Technique sensitive
Retention decreased with time (
longevity questionable )
Eg: Clearfill new bond
Scotchbond new

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Fourth generation
• Characterized by : Complete removal of smear layer
Total etch technique
( simultaneous etching of enamel and dentin)
• Mechanism of action
-Etching removes smear layer, opens the tubules upto 7.5 microns and increases the
permeability.
- Primer wets & penetrates the collagen meshwork and increases its surface energy and
wettability into which the resin flows.
- Based on diffusion and impregnation of resin into partially decalcified dentin followed by
polymerisation creating a resin reinforced layer-Hybrid layer

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• Advantages
- Less technique sensitivity
- Similar bond strengths to both enamel and dentin
- can bond to other surfaces like metals, amalgam, porcelain
• Bond strength: 18 Mpa
• Disadvantages
- Unless the primer and adhesive are applied, the overlying composite resin will not bond to
the surface

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Fifth generation
• Simplify the number of steps
• Characterized by combinations of primer and adhesive in one step
• Separate etch and rinse
• Rely on wet bonding technique
• Bond strength- 17 – 24 MPa.

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• Advantages –
Good bond strength
Very rare post operative sensitivity
Less no of applications -easy to use
• Some agents have flouride and elastomeric components incorporated for better marginal integrity

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Sixth generation
• Here the primer and etchant are combined in one step.( Self etching primers).
• Available in two types –
two step self etching primers
single step self etching primers ( all in one systems )
• Ex - Two step SEPs Single step SEPs
NRC Non Rinse Conditioner
Prime and Bond NT( Dentsply)
Clearfil SE Bond
Clearfil Liner Bond IIV.
Simplicity
UniFil Bond
AdheSE
Prompt L Pop
Touch and Bond
Brush and Bond
Xeno III

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Advantages
- No acid etch with phosphoric acid
- No post conditioning rinsing required
- Reduced post operative sensitivity
- Simultaneous demineralization and
resin infiltration
- Less sensitive to degree of wetness and
dryness
- Single dose packaging possible. So less
chance of cross infection
- Low technique sensitivity
Disadvantages
- Less effective bonding of enamel
- Initial bond might deteriorate with
ageing, which could lead to
premature failures
- Bonding to sclerotic and caries
affected dentin might be problematic
- May inhibit set of self cure or dual
cure resin materials

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Seventh Generation
• Fluoride releasing
• Self etching type
• Characterized by etching, priming and bonding in a simple application with no rinsing or drying
• All in one system
• Disadvantages:
- prone to phase seperation
- adhesive layer can act as semi-permeable membrane
- low bond strength

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IBond
• Single step no mix bonding system
• Five in one solution:
➢ Etch
➢ Disinfect
➢ Desensitize
➢ Prime
➢ Bond

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G bond
• An advanced formulation of Phosphoric acid ester monomer
• Phosphoric acid ester monomer provides consistent bond strength to enamel
• Based on nano interaction technology

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Total etch adhesives
• Total etching is the simultaneous etching of enamel and dentin
• The ph of these formulations is between 2.5 to 4.5 ( too high )
to demineralise smear layers and etch dentin
• Hence a separate etch and rinse phase involved
• Mechanism of action –
Smear layer removed by etch and rinse phase,
3-5micron deep demineralization of the dentin surface.
a microretentive network for micromechanical interlocking of monomers.

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3 step Total etch
• Conditioning
Priming
Application of adhesive resin
• Amalgam- bond
• Clearfil Liner Bond
• Imperva Bond
• Optibond
• Scotch bond multipurpose
Etchant
Primer
Adhesive

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Advantages Disadvantages
• Separate application of
conditioner, primer and adhesive
• Low technique sensitivity
• Best long term results
• Proves effectiveness of adhesion to
enamel and dentin
• Risk of overetching
• Incomplete resin infiltration
• Risk of surface contamination (post
conditioning rinse)
• Time consuming

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2 Step total etch
• Conditioning
• Primer and adhesive
• Eg:
Gluma comfort bond
Prime and bond NT
Prime and bond 2.1
Etchant
Primer
and
Adhesive

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• Simpler application
• Consistent and stable
composition
• Particle filled adhesive acts as
shock absorber
• More technique sensitive
• Risk of over etching
• Lower bonding effectiveness
than 3 step total etch

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Self etch adhesives
• These adhesive systems are based on the use of non rinse acidic monomers that simultaneously
condition and prime dentin and enamel.
• Features :
Here the conc of acidic monomers was increased from 5-10% wt to 30-40% wt
These acidic monomers were dissolved in 30-40% HEMA
Formulation that was both self etching and self priming
ph low enough to etch through the smear layers to underlying dentin.

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Two step self etching primer
• Ex -
Clearfil SE Bond
Clearfil Liner Bond IIV.
Simplicity
UniFil Bond
AdheSE
Self –Etching
Primer
Adhesive

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• No etching, post conditioning
rinsing or drying
• Simultaneous
demineralisation and resin
infiltration
• Effective dentin desensitizer
• Better mechanical strength
• Contains water and may
affect polymerization
• Incompatible with autocuring
resins
• Impaired durability
• Promotes water sorption

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Single step self etching primer
• Ex -
Prompt L Pop
Touch and Bond
Brush and Bond
Xeno III
All in
one
adhesive

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• Time efficient
• Simultaneous
demineralisation and resin
infiltration
• Less sensitive to dentin
wetness
• Prone to phase separation
• Insufficient long term clinical
research
• Water sorption

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•It is dual-cured and works with all light, self or dualcured resins
•Nanosized cross linking agents with fused silica particles
•It works in a self-cured mode without any light – great for endo
• It takes only 35 sec. from start to finish.
• It needs only one coat.
Futurabond DC- 8th Generation

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Surpass: A Universal Eighth Generation
Bonding System
• Has the best attributes of the fourth generation and the ease of the sixth-generation
bonding systems
• Consists of three bottles: an etchant/conditioner, a primer, and a separate hydrophobic
bonding resin
• Etchant/conditioner is not rinsed from the tooth.
• Bond Strength: 50 Mpa

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Effect of Cyclic Loading on the Microtensile Bond Strengths of Total-etch and Self-etch
Adhesives
M. Toledano, R. Osorio, A. Albaladejo, F. S. Aguilera, F. R. Tay, and M. Ferrari
• Total-etch adhesives (Single Bond, Prime&Bond NT and Prime&Bond XP)
• Two-step self-etching primer (Clearfil SE Bond)
• All-in-one adhesive (Etch&Prime 3.0)
• Clearfil SE Bond and Single Bond attained higher MTBS than the other three adhesives.
• Prime&Bond NT and Prime&Bond XP performed equally, and Etch&Prime 3.0 resulted in the lowest
MTBS.
• After mechanical loading, MTBS decreased in all groups except Prime&Bond XP

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Bonding of Self-etch and Total-etch Adhesives to Carious Dentin M. Yoshiyama, F.R. Tay
• Microtensile bond strength of a total-etch adhesive and an experimental self-etching adhesive (ABF)
to caries-infected, caries-affected, and sound dentin
• The bond strengths of both adhesives to sound dentin were significantly (p < 0.05) higher than those
to caries-affected dentin, which, in turn were significantly (p < 0.05) higher than those to caries-
infected dentin
• For both adhesives, hybrid layers in caries-affected dentin were thicker but more porous than those
in sound dentin
• The lower bond strengths may be due to the lower tensile strength of caries-affected dentin

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Amalgam Bonding
• Bond strengths have been reported to range from 2 to 20 MPa, with higher bond strengths
reported for filled adhesives
• Benefits include decreased microleakage between the cavity wall and the restorative material.
This, in turn, may decrease post-operative sensitivity, pulpal inflammation and the incidence of
recurrent caries
• In vitro studies have reported one potential problem in the incorporation of resin into
amalgam, which may cause a decrease in strength of the restoration
Oper Dent 2000 mar-apr25(2)

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• Extra retention for the restoration may also be provided and the need for cavities to rely
on traditional retention and resistance form may be decreased or even eliminated, thus
conserving precious tooth tissue
• Formation of hybrid layer by dentin bonding agent prevents permeation of corrosion
products into dentinal tubules there by, preventing tooth discoloration
Dent update 2011 may38(4)

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Ceramic Bonding
• Ceramic restorations can be bonded to tooth structure
• Acid etching with solutions of hydrofluoric acid (HF) or ammonium bifluoride
• The glassy matrix is selectively removed, and crystalline structures are exposed
• HF solutions between 2.5% and 10% applied for 2 to 3 minutes seem to be most successful
• Silane coupling agent is applied on the etched surface and air dried
• Coupling agent acts as a primer and makes the inorganic substrate more receptive to organic
surface
• They can also increase the bond strength between the restoration and tooth
Resin-ceramic bonding:JPD 2003

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Failures in bonding
• Can occur at various levels
- between mineralised and demineralised dentin
- between demineralised dentin and bonding agent
- within layer of bonding agent
- between bonding agent and composite resin.

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Recent Advances in Dentin Bonding Systems –
Literature Review
Anti-biofilm Dentin Primer with Quaternary Ammonium and Silver Nanoparticles
Novel antibacterial dentin primers containing quaternary ammonium
dimethacrylate (QADM) and Nanoparticles of silver (NAg)
Strongly antibacterial without compromising dentin bond strength,
and hence are promising to inhibit biofilms and secondary caries
L. Cheng et al; J Dent Res 91(6):598-604, 2012

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Novel dental adhesives containing nanoparticles of silver and amorphous calcium
phosphate
The objectives of this study were to incorporate nanoparticles of silver (NAg) and nanoparticles
of amorphous calcium phosphate (NACP) into adhesive for the first time, and to investigate
the effects on dentin bond strength and plaque microcosm biofilms
Mary Anne S. Melo et al; DENTAL MATERIALS 29 (2013) 199–210
Significance Dental plaque microcosm biofilm viability and acid production - greatly reduced on
bonding agents containing NAg and NACP, without compromising dentin bond strength. The
novel method of incorporating dual agents (remineralizing agent NACP and antibacterial agent
NAg) may have wide applicability to other dental bonding systems

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Hydroxyapatite nanorods as novel fillers for improving theproperties of dental
adhesives: Synthesis and application
This study evaluates the hypothesis that the incorporation of fibrous hydroxyapatite
nanoparticles with high crystallinity and high aspect ratio, synthesized by hydrothermal
method, into an experimental ethanol-based one-bottle dentin adhesive, improves the
mechanical properties of the adhesive layer, and accordingly increases the bond strength to
dentin
Mehdi Sadat-shojai Et Al; Dental Materials 26 (2010) 471–482
Significance: Hydroxyapatite-based composites have shown promising bioactivity.
However,the knowledge about the influence of the nano-sized HAp on the properties of the
dental
materials, especially dentin bonding adhesives, is yet insufficient. The nanorod containing
adhesive system presented here might be considered to have practical applications in dental
clinics.

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Inductive Therapeutic Function with Doped Dental Adhesives
• Dentine adhesives - promoters of both protection and remineralisation of resin-dentine
interfaces - triggering the bioactive nature of dentine matrix - releasing bound bioactive
molecules
• Several doping compounds - biologically active agents have been incorporated into dental
adhesives
• Eg :- Bioactive glass, Portland cement or amorphous calcium phosphate – decreases
mechanical properties – controvertial
Manuel Toledano et al; New Advanced Materials for High Performance at the Resin-Dentine Interface; Biomaterials for Oral
and Craniomaxillofacial Applications; Karger, 2015, vol 17, 39–48

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• Zinc has been proposed as a doping agent in dental adhesives
• Zn is a cofactor of many enzymes and is essential for DNA replication - potent inhibitory
effect on osteoblastic bone resorption and can modify the production of cytokines
• Zinc ions inhibit MMPs and reduce collagen degradation in demineralised dentine
• Zinc has been shown to promote binding between collagen and other oligomeric matrix
proteins

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Comparative evaluation of microleakage of fifth, sixth, and seventh generation
dentin bonding agents: An in vitro study
Objectives: To determine the microleakage in the 5th and 6th generation bonding agents with that
compared with the newly introduced 7th generation bonding agents using three bonding agents
Results: This study showed that at the coronal margin and the apical margins, the preparations treated
with Clearfil S3 showed significantly less leakage than the other groups. Enamel margins provided
better marginal sealing than dentin/ cementum margins
Vinay S, Vasundhara Shivanna; Journal of Conservative Dentistry;Jul-Sep 2010 ;Vol
13;Issue 3

75
• Interpretation and Conclusion: The study demonstrated that Clearfil S3 bond had a better sealing
ability at both coronal (enamel) and apical (dentin/cementum) margins compared with the other
dentin bonding agents used

76
Effect of UVA-activated Riboflavin on Dentin Bonding
• Recent studies have reported collagen cross-linking after exposure to riboflavin
followed by ultraviolet-A (UVA) exposure
• This study is the first to investigate the effect of a riboflavin-containing primer on
adhesive interface stability and dentinal matrix metalloproteinase activity
A. Cova et al; J Dent Res 90(12):1439-1445, 2011
Ultraviolet-activated riboflavin treatment increased the immediate bond strength to
dentin at all aging intervals and decreased interfacial nanoleakage in aged specimens

77
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Conclusion
Most currently marketed adhesive systems produce immediate
bond strength that allows clinician to bond to tooth
structure without the use of retentive cavity preparations
Nevertheless, major concerns have been recently expressed
regarding interfacial aging due to degradation of the hybrid
layer, related to water sorption, hydrolysis of the resin and
disruption of the collagen network
Interestingly, the new simplified adhesives exhibited not only
the lowest bond strengths, but also the least predictable
clinical performances when compared with the multi-step
etch-and-rinse and self-etch systems

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References
• CURRENT CONCEPTS ON ADHESION TO DENTIN-J.D. Eick
• Adhesion to Enamel and Dentin: Current Status and Future Challenges- B Van Meerbeek
• Water treeing-a potential mechanism for degradation of dentin adhesives- Tay FR,Pashley
• Effects of dentin permeability on restorative dentistry –Dent clin N Am 46 2002
• Hybridization of dental hard tissues – Nakabayashi ,David pashley
• Dental adhesion review: Aging and stability of the bonded interface Lorenzo Breschi
• Effects of water on dentin bonding Thomas Jacobsenl, Karl-Johan Siiderholm
• The smear layer in endodontics – a review D. R. Violich1 & N. P. Chandler
• Operative Dentistry 2000 mar-apr25(2)
• Dental update 2011 may38(4)
• Resin-ceramic bonding:JPD 2003
• Effect of Cyclic Loading on the Microtensile Bond Strengths of Total-etch and Self-etch Adhesives
M. Toledano, R. Osorio, A. Albaladejo, F. S. Aguilera, F. R. Tay, and M. Ferrari
• Bonding of Self-etch and Total-etch Adhesives to Carious Dentin M. Yoshiyama, F.R. Tay
• Fundamentals of Operative Dentistry: A Contemporary Approach-James B. Summitt
• Phillips' Science of Dental Materials-By Kenneth J. Anusavice
• Sturdevant's Art & Science of Operative Dentistry

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