DENTIN BONDING AGENTS · • BRAND NAME-Clearfil New Bond,Scotch Bond 2,Optibond,Gluma • MECHANISM- Did not remove the entire smear layer, but rather modified it • BOND STRENGTH:8

DENTIN BONDING AGENTS

Dr. Parul Bansal, Subharti Dental College, SVSU

COMPONENTS of

ADHESIVE SYSTEM

ETCHANT

PRIMER ADHESIVE

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Conditioner

(Cleanser,

Etchant)

Is usually a

weak organic acid (e.g., maleic acid) or

low concentration of a stronger inorganic acid (e.g., phosphoric or nitric acid) or

chelating agent (e.g., EDTA).

AGENTS USED FOR ACID ETCHING

35-40% phosphoric acid 2% sulphuric acid 10% pyruvic acid 10% maleic acid 10% citric acid 2.5% oxalic acid 2.5% nitric acid EDTA Laser etching

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PRIMER • (Adhesion Promoter, Adhesion Enhancer,Bifunctional

Monomer, Hydrophilic Monomer)

Is usually a bifunctional monomer in organic solvents such as acetone or alchohol or water

examples – HEMA (hydroxyethyl methacrylate),

MAIN ACTIONS Contain monomers with hydrophilic properties having an affinity

for moist dentin & hydrophobic properties for co-polymerization with adhesive resin.

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Adhesive(Bonding Resin, Sealing Resin)

Most common monomers are

2,2,bis(4-[3-methacryloyloxy-2-hydroxypropoxy]phenyl)propane [bis-GMA], & urethane dimethacrylate[UDMA]

triethyleneglycol dimethcrylate[TEGDMA] as viscosity regulator

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1ST GENERATION

• CHEMICAL-surface active co-monomer NPG-GMA(N-phenylglycine methacrylate)

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

• BRAND NAME-Cervident

• BOND STRENGTH:2-3MPa-Tendency to debond within a short time

• PROBLEMS ENCOUNTERED

Loss in bond strength over time

Lack of stability of individual component during storage

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2ND GENERATION • CHEMICAL-Phosphate –ester material(phenyl-p &

HEMA in ethanol).

• MECHANISM-Polar interaction between –vely charged phosphate groups in the resin & +vely charged calcium ions in the smear layer.

• Smear layer was the weakest link in the system because of its relatively loose attachment to the dentin surface.

• BRAND NAME-Clearfil bond system,scotchbond(3M EPSE),Bondlite

prisma universal bond

• BOND STRENGTH-1-5MPa

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3rd GENERATION • CHEMICAL-Phosphate based material containing HEMA &

a 10 carbon molecule as 10MDP which include long hydrophobic & short hydrophilic components.

• BRAND NAME-Clearfil New Bond,Scotch Bond 2,Optibond,Gluma

• MECHANISM-

Did not remove the entire smear layer, but rather modified it

• BOND STRENGTH:8 to 15 Mpa

• COMPONENTS

a) Dentin-conditioner

b) Dentine primers / adhesive

c) Bonding agent

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Etch & rinse adhesives

Three step-etch & rinse adhesive

(4th generation)

Two step-etch & rinse adhesive

(5th generation)

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ETCH AND RINSE ADHESIVES 38


As,the clinical technique involves simultaneous

application of an acid to enamel & dentin,this

method is called as total etch technique .

Application of acid to dentin results in partial or total

removal of smear layer & demineralization of underlying

dentin

Acids demineralize intertubular & peritubular dentin,open the dentinal tubules,& expose a dense filigree of collagen

fibres,increasing the microporosity of intertubular dentin.

Dentin is demineralized upto 7.5um

4th GENERATION

THREE STEP, TOTAL

ETCH ADHESIVES

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5TH GENERATION

• One-bottle,Total-Etch Adhesives

• They combine the primer & bonding agent into a single solution.

• A separate etching step is still required

• Bond strength is almost equal to 4th generation

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Self -etch system

Two component –self etch system

(6th generation)

Two step-two component-self

etch primer

One step-two component-self etch adhesive

Single component-one step-self etch

adhesive

(7th generation)

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SELF ETCH SYSTEM 46


self etch primer systems 6th GENERATION

In contrast to conventional etchants, SEPs are not rinsed off.

COMPOSITION-acidic monomers,such as MET & 10-MDP .They render self etch adhesives much more hydrophilic

Water - needed for acidic monomers to ionize & trigger demineralization of dental hard tissue

Bonding mechanism of SEPs is based on simultaneous etching & priming of enamel & dentin,forming a continum in substrate &

incorporating smear plugs into the resin tags

Elimination of rinsing & drying steps reduces the possibility of overwetting or overdrying either of which can effect adhesion

adversely

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Type I

•Self etching primer •Includes acidic primer and adhesive, applied separately to tooth. •Compatible with self cured composite •Eg. Nanobond Unifil bond

Type II

•Self etching adhesive •Includes acidic primer and adhesive, first mixed and then applied to tooth. •Not compatible with self cured composite •Eg. Xeno III, One up bond

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self etch adhesive

• 7th GENERATION

• Comprised of the one-step self-etch adhesive

• All the primary components of an adhesive system into a single solution.

• Due to complex nature of mixed solutions,they are more prone to phase seperation & formation of droplets within their adhesive layers.

• Have lower bond strength than 4th & 5th generation

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DENTIN BONDING AGENTS · • BRAND NAME-Clearfil New Bond,Scotch Bond 2,Optibond,Gluma • MECHANISM- Did not remove the entire smear layer, but rather modified it • BOND STRENGTH:8

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