Genaerations of Adhesives

Bis-EMA

Bis-GMA

EDTA

GPDM

HEMA

(Bis-EMA) Bisphenol A ethoxylated dimethacrylate

(Bis-GMA) Bisphenol A-glycidyl methacrylate

(EDTA) Ethylenediamine tetra-acetic acid

(GPDM) Glycerophosphoric acid dimethacrylate

(HEMA) Hydroxyethyl methacrylate

10-MDP

4-META

NPG-GMA

PENTA

Phenyl-P

UDMA

(10-MDP) 10-Methacryloyloxy decyl dihydrogen phosphate

(4-META) 4-Methacryloxyethyl trimellitate anhydride

(NPG-GMA) N-phenylglycine glycidyl methacrylate

(PENTA) Dipentaerythritol penta-acrylate monophosphate

(Phenyl-P) 2-(Methacryloxy) ethyl phenyl hydrogen phosphate

(UDMA) Urethane dimethacrylate

Beginning

• Glycerophosphoric Acid Dimethacrylate (GPDM)

• Could bond to a hydrochloric acid-etched dentin surface

First Generation

• Cervident

• (NPG-GMA) N-phenylglycine glycidyl methacrylate

• This co-monomer could chelate with calcium on the tooth surface to generate water-resistant chemical bonds of resin to dentinal calcium

First Generation
in vitro dentin bond strength:
In vivo results:

- in vitro dentin bond strengths = 2 to 3 Mpa

- In vivo results: Cervident had poor clinical results when used to restore non-carious cervical lesions without mechanical retention

Second Generation

• Clearfil Bond System F(1st product in 2nd gen)

• Phosphate ester material (phenyl-P and hydroxyethyl methacrylate (HEMA) in ethanol)

• polar interaction between negatively charged phosphate groups in the resin and positively charged calcium ions in the smear layer

It was the weakest link in the system(2nd gen) because of its relatively loose attachment to the dentin surface

Smear Layer

Several other phosphate-ester dentin bonding system - were introduced in the early 1980s (2nd Generation) including:

• Scotchbond

• Bondlite

• Prima Universal Bond

Second Generation In vitro bond strength:

Problem:

• In vitro bond strengths: 1 to 5 Mpa

• The bonding material tended to peel from the dentin surface after water storage, indicating that the interface between dentin and some types of chlorophosphate ester-based materials was unstable.

is the estimated threshold value for acceptable retention in vivo

10-Mpa

The concept of phosphoric acid-etching of dentin before application of a phosphate ester-type bonding agent was introduced by

Fusayama et al in 1979(Third Generation)

Kuraray introduced in 1984

Clearfil Now Bond

Third Generation

• Clearfil Now Bond

• Phosphate-based material contained HEMA and a 10-carbon molecule known as 10 MDP, which includes long hydrophobic and short hydrophilic components

• Modify the Smear Layer

Third Generation is designed not to remove the entire smear layer but to modify it and allow penetration of acidic monomers, such as

phenyl-P or PENTA

Used to Modify the Smear layer in Third generation

Treatment of the smear layer with acidic primers was proposed using an aqueous solution of 2.5% maleic acid, 55% HEMA, and a trace of methacrylic acid.(Scotchbond 2)

was the first dentin bonding system to receive "provisional" and "full acceptance" from the ADA.

Scotchbond 2

What is the Original Gluma system

The removal of the smear layer using chelating agents such as EDTA before the application of a primer solution of 5% glutaraldehyde and 35% HEMA in water

Most other third-generation materials were designed ______________, but to ________ and allow penetration of acidic monomers

Most other third-generation materials were designed not to remove the entire smear layer, but to modify it and allow penetration of acidic monomers

WHAT ARE THE CURRENT STRATEGIES FOR ADHESION OF RESINS TO DENTIN

• THREE STEP ETCH AND RINSE( FOURTH GENERATION ADHESIVES)

  • (E + P+B]

• TWO-STEP ETCH-AND-RINSE ADHESIVES (FIFTH GENERATION ADHESIVES)

  • E +[PB]

• TWO STEP SELF ETCH SYSTEM (SIXTH GENERATION ADHESIVES)

  • [(E+P) + B]

• ONE- STEP SELF ETCH ADHESIVE(SEVENTH GENERATION ADHESIVES)

  • [EPB]

• EIGHT GENERATION ADHESIVES

• THREE STEP ETCH AND RINSE( FOURTH GENERATION ADHESIVES)

  • (E + P+B]

• Also known as?

"total-etch technique"

Generations that Removes the Smear Layer

• THREE STEP ETCH AND RINSE( FOURTH GENERATION ADHESIVES) (E + P+B]

• TWO-STEP ETCH-AND-RINSE ADHESIVES (FIFTH GENERATION ADHESIVES)E +[PB]

Three Essential Components of Fourth Genaration of Adhesives

1. Phosphoric acid-etching gel

2. Primer

3. Unfilled or filled resin bonding agent

Third Generation

total-etch technique - because the clinical technique

involves simultaneous application of an acid to enamel

and dentin

1. Phosphoric acid-etching gel - that is _________

2. Primer - reactive _____________

3. Unfilled or filled resin bonding agent - aka _____; _________ such as _____, frequently combined with ________ molecules such as _____

Third Generation

total-etch technique - because the clinical technique

involves simultaneous application of an acid to enamel

and dentin

1. Phosphoric acid-etching gel - that is rinsed off

2. Primer - reactive hydrophilic monomers in ethanol, acetone, or water

3. Unfilled or filled resin bonding agent - aka adhesive; hydrophobic monomers such as Bis-GMA, frequently combined with hydrophilic molecules such as HEMA

1- Phosphoric acid etching of dentin removes

hydroxyapatite, which has ________,

exposing the low surface energy _______.

For good interfacial contact, adhesive must have ___

___________ and the substrate must have

______________

2- The primer is designed to increase the _________ of dentin

3- The primer and bonding resin are applied to

etched dentin, penetrate the intertubular dentin,

forming a resin-dentin interdiffusion zone or hybrid

layer; they also penetrate and polymerize in the open

dentinal tubules, forming ________

1- Phosphoric acid etching of dentin removes

hydroxyapatite, which has high surface energy,

exposing the low surface energy collagen.

For good interfacial contact, adhesive must have low

surface tension and the substrate must have

high-surface energy.

2- The primer is designed to increase the critical

surface tension of dentin

3- The primer and bonding resin are applied to

etched dentin, penetrate the intertubular dentin,

forming a resin-dentin interdiffusion zone or hybrid

layer; they also penetrate and polymerize in the open

dentinal tubules, forming resin tags.

Was introduced by Nobuo Nakabayashi in 1982

Hybrid layer

PROCEDURE(ETCHING)

1. Etchant

- Etchant is applied to the enamel first and then to the dentin after approx. _________.

- It is rinsed off after another _______

- The total etch time for the enamel, which has a higher proportion of inorganic content, is therefore _________

PROCEDURE(ETCHING)

1. Etchant

- Etchant is applied to the enamel first and then to the dentin after approx. 10 seconds.

- It is rinsed off after another 20 seconds.

- The total etch time for the enamel, which has a higher proportion of inorganic content, is therefore 30 seconds.

PROCEDURE(ETCHING)

● Care should be taken not to over etch the

enamel to avoid the tooth structure becoming

_______

● Acids in current use demineralize the dentin to

a ___________ and therefore do not

affect or directly damage the pulp.

● The etch gel must be rinsed off very carefully;

this should take _________ as application

(approx. 1 min. in total).

● The______ should be rinsed off first with

water before using a water-air spray to prevent

splashes.

PROCEDURE(ETCHING)

● Care should be taken not to over etch the

enamel to avoid the tooth structure becoming

too brittle.

● Acids in current use demineralize the dentin to

a depth of 1 - 10 um and therefore do not

affect or directly damage the pulp.

● The etch gel must be rinsed off very carefully;

this should take twice as long as application

(approx. 1 min. in total).

● The etch gel should be rinsed off first with

water before using a water-air spray to prevent

splashes.

PROCEDURE(ETCHING)
● ______________ is another critical stage. If the residual dentin is overdried, the collagen fibres _______ and prevent adhesion;

● On the other hand, if the dentin is too moist, the _________ resin cannot adequately ___________

● The dentin should have a ______ appearance prior to application of the primer

● It is advisable to protect the adjacent teeth of the tooth to be treated before applying the etch gel. A _______ can be used to protect the healthy tooth structure

PROCEDURE(ETCHING)

● Removal of excess water is another critical stage. If the residual dentin is overdried, the collagen fibres collapse and prevent adhesion;

● On the other hand, if the dentin is too moist, the hydrophobic resin cannot adequately infiltrate the tubules.

● The dentin should have a moist appearance prior to application of the primer

● It is advisable to protect the adjacent teeth of the tooth to be treated before applying the etch gel. A teflon strip can be used to protect the healthy tooth structure

2. Primer

-Great care should be taken during clinical application of the primer, which should be allowed to react for a minimum of _____

-At the end of the reaction time the volatile components (solvents) are ________with an __________ (pointed towards the dental mirror).

2. Primer

-Great care should be taken during clinical application of the primer, which should be allowed to react for a minimum of 30 seconds.

-At the end of the reaction time the volatile components (solvents) are evaporated with an indirect jet of air (pointed towards the dental mirror).

PROCEDURE: PRIMER

● The moistness of the dentin prevents infiltration of the hydrophobic adhesive after conditioning. This is why __________________ is required beforehand with a primer that contains amphiphilic monomers, e. g. HEMA, PENTA, or 4-META, in organic solvents.

● By using solvents such as ___________ , the monomers are able to infiltrate inside the organic structure. This ______ the water content inside the dentine tubules and replaces it with the _______ .

PROCEDURE: PRIMER

●The moistness of the dentin prevents infiltration of the hydrophobic adhesive after conditioning. This is why hydrophobic conditioning of the dentin is required beforehand with a primer that contains amphiphilic monomers, e. g. HEMA, PENTA, or 4-META, in organic solvents.

● By using solvents such as ethanol or acetones/H20, the monomers are able to infiltrate inside the organic structure. This displaces the water content inside the dentine tubules and replaces it with the monomers.

PROCEDURE: PRIMER

A __________ remains after the solvent has been completely ________. The primer in the dentin renders it _________ and compatible with the adhesive

PROCEDURE: PRIMER

A thin monomer film remains after the solvent has been completely evaporated. The primer in the dentin renders it hydrophobic and compatible with the adhesive

PROCEDURE: BONDING

3. Bonding Agent - It is also important during this stage to apply the adhesive very ______________

- A _____ brush should always be used from the one used for applying the primer: a ________is recommended

-Depending on the adhesive used, the adhesive layer should be polymerized for at least ___- ___ _________

PROCEDURE: BONDING

3. Bonding Agent - It is also important during this stage to apply the adhesive very uniformly over the entire cavity

- A different brush should always be used from the one used for applying the primer: a microbrush is recommended

-Depending on the adhesive used, the adhesive layer should be polymerized for at least 20-40 seconds.

● The adhesive, which is applied after the enamel-dentin structure has been conditioned, is resin-based and consists mainly of?

hydrophobic monomers, e. g. Bis-GMA or UDMA

During polymerization, the shape and depth of the cavity should be taken into account: the greater the distance between the light-emission window of the lamp and the surface to be polymerized, the __________

longer the exposure time.

Following polymerization, the conditioned surface should have a ___________ Otherwise, the last step of adhesive conditioning should be repeated, and the surface checked again

Shiny appearance

THREE STEP ETCH AND RINSE( FOURTH GENERATION ADHESIVES) (E + P+B]

Advantages

Advantages

● Highly Effective on Both enamel and Dentin

● Long term clinical Results

● Highly effective on porcelain and Metal

● Can be used with Dual-curing composites

THREE STEP ETCH AND RINSE( FOURTH GENERATION ADHESIVES) (E + P+B]

DISADVANTAGES

THREE STEP ETCH AND RINSE( FOURTH GENERATION ADHESIVES) (E + P+B]

Disadvantages

● Technique-sensitive; success greatly depends

on the skill of the operator

● Risk of overetching

● Risk of dry leakage

● Requires-multilayer application

TWO-STEP ETCH-AND-RINSE ADHESIVES (FIFTH GENERATION ADHESIVES) E +[PB]

Is also known as?

one-bottle

TWO-STEP ETCH-AND-RINSE ADHESIVES (FIFTH GENERATION ADHESIVES) E +[PB]

• A separate etching technique is still required .The primer-contains _____ and _______ components

• Mixed with the ____________ from the bonding agent

TWO-STEP ETCH-AND-RINSE ADHESIVES (FIFTH GENERATION ADHESIVES) E +[PB]

• A separate etching technique is still required .The primer-contains solvents and hydrophilic components

• Mixed with the hydrophobic monomer from the bonding agent

they combine primer and bonding agent into a single solution

One-bottle system(5th generation of adhesives)

TWO-STEP ETCH-AND-RINSE ADHESIVES (FIFTH GENERATION ADHESIVES) E +[PB]

_________ and the __________ of the adhesive have been shown to somewhat compensate for the lack of a ________________ layer as the last step in two-step etch-and-rinse adhesives

TWO-STEP ETCH-AND-RINSE ADHESIVES (FIFTH GENERATION ADHESIVES) E +[PB]

Active rubbing application and the use of multiple coats of the adhesive have been shown to somewhat compensate for the lack of a hydrophobic resin bonding agent layer as the last step in two-step etch-and-rinse adhesives

TWO-STEP ETCH-AND-RINSE ADHESIVES (FIFTH GENERATION ADHESIVES) E +[PB]

Advantages

Advantages

● Optimum effect on both enamel and dentin

● Long-term clinical results

● Option of filling the adhesives with filling

materials(fillers)

● Application in only one step after etching

TWO-STEP ETCH-AND-RINSE ADHESIVES (FIFTH GENERATION ADHESIVES) E +[PB]

Disadvantages

Disadvantages

● Technique-sensitive; success greatly depends

on the skill of the operator

● Risk of over etching

● Risk of Dry leakage

● Requires incremental application

TWO STEP SELF ETCH SYSTEM (SIXTH GENERATION ADHESIVES) [(E+P) + B]

• Enamel etch is typically __________

• First step is application of an etchant/primer component that modifies the ______ and acts as a _________

TWO STEP SELF ETCH SYSTEM (SIXTH GENERATION ADHESIVES) [(E+P) + B]

• Enamel etch is typically shallow

• First step is application of an etchant/primer component that modifies the hybrid layer and acts as a bonding agent.

TWO STEP SELF ETCH SYSTEM (SIXTH GENERATION ADHESIVES) [(E+P) + B]

● The component is applied to the _______ and an adequate reaction time has to be allowed before the _____ is applied.

TWO STEP SELF ETCH SYSTEM (SIXTH GENERATION ADHESIVES) [(E+P) + B]

● The component is applied to the entire cavity and an adequate reaction time has to be allowed before the adhesive is applied.

● Some self-etch systems are most accurately described as

non-rinsing conditioners or self-priming etchants.

Enamel etch is typically shallow on these generations

TWO STEP SELF ETCH SYSTEM (SIXTH GENERATION ADHESIVES) [(E+P) + B]

ONE STEP SELF ETCH SYSTEM(SEVENTH GENERATION ADHESIVES)[EPB

What does SEPs do?

does not remove the smear layer, but fixes it and exposes about 0.5-1 um of intertubular collagen because of its acidity (pH = 1.2- 2.0)

• Contains a phosphonated resin molecule that performs two functions simultaneously - etching and priming of dentin and enamel

• Not rinsed off and combines with the smear plugs

Self Etching Primers(SEPs)

TWO-STEP SELF- ETCH SYSTEM Advantages

Advantages

● Optimum effect on dentin

● Fewer clinical steps

● Chemical bond with dentin

● Less technique-sensitive

TWO-STEP SELF- ETCH SYSTEM Disadvantages

Disadvantages

● No optimum effect on unprepared enamel

● Multilayering technique

TWO-STEP SELF- ETCH SYSTEM

- Less technique-sensitive(advantage) - less likely to result in discrepancy between the depth of demineralization and depth of resin infiltration because SEPs ____________

- No optimum effect on enamel(disadvantage)- do not etch enamel as much as ___________

TWO-STEP SELF- ETCH SYSTEM

- Less technique-sensitive(advantage) - less likely to result in discrepancy between the depth of demineralization and depth of resin infiltration because SEPs demineralize and infiltrate dentin simultaneously.

- No optimum effect on enamel(disadvantage) - do not etch enamel as much as phosphoric acid

ONE- STEP SELF ETCH ADHESIVE(SEVENTH GENERATION ADHESIVES)

[EPB]

• also known as? _______

•This forms a _______ without the need for any

further working stages.

• Etches enamel, but etch pattern is typically ______

• Incorporates the ________ into interface

• Applied in __________ (rubbing on substrate)

ONE- STEP SELF ETCH ADHESIVE(SEVENTH GENERATION ADHESIVES)

[EPB]

• also known as "all-in-one" adhesives

•This forms a hybrid layer without the need for any

further working stages.

• Etches enamel, but etch pattern is typically shallow

• Incorporates the smear layer into interface

• Applied in multiple coats (rubbing on substrate)

ONE- STEP SELF ETCH ADHESIVE(SEVENTH GENERATION ADHESIVES) [EPB]

• Behave as ___________ , resulting in a hydrolytic degradation of the resin-dentin interface. - Since this is semi-permeable the junction of adhesive resin is _______

• Resin monomers - are_______ , which makes them liable to ___________. - High hydrophilicity.

ONE- STEP SELF ETCH ADHESIVE(SEVENTH GENERATION ADHESIVES) [EPB]

• Behave as semi-permeable membranes, resulting in a hydrolytic degradation of the resin-dentin interface. - Since this is semi-permeable the junction of adhesive resin is degraded

• Resin monomers - are too hydrophilic, which makes them liable to water degradation. - High hydrophilicity.

•2010- Voco America introduced nano filled dentin bonding agent

Futura Bond DC

Average particle size of Eight generation of Adhesives

12nm

Advantages of nanofiller in adhesive(eight generation)

1. Increases the penetration of resin monomers and hybrid layer thickness Improving the mechanical properties of the bonding system

2. Higher bond strength

3. Longer shelf Iife

4. Aids in stress absorption They are available for single or multiple use in direct and indirect restorations

filler size that may cause cracks and decrease bond strength

15-20 nm