dentin bonding agents

CONTENTS
 INTRODUCTION
 ROLE OF ADHESIVE DENTISTRY
 CONCEPT OF ADHESION
ENAMEL ADHESION
DENTINE ADHESION
CHALLENGES IN DENTINE ADHESION
 ENAMEL BONDING
STEPS FOR ENAMEL BONDING
MECHANISM INVOLVED

 DENTINE BONDING
CONDITIONING OF DENTINE
PRIMING OF DENTINE
 DENTINE BONDING AGENTS
CLASSIFICATION
GENERATIONS OF BONDING AGENTS
FIRST GENERATION
SECOND GENERATION
THIRD GENERATIONS
FOURTH GENERATION
FIFTH GENERATION
SIXTH GENERATION
SEVENTH GENERATION

 ROLE OF MICROLEAKAGE
 BIOCOMPATIBILITY
 ANTIBACTERIAL PROPERTY
 CLINICAL FACTORS IN DENTINE ADHESION
 NEWER CLINICAL INDICATIONS OF DENTINE
ADHESIVES
DESENSITISATION
ADHESIVE AMALGAM RESTORATIONS
INDIRECT ADHESIVE RESTORATIONS
 FAILURES IN DENTINE BONDING
 SUMMARY
 BIBLIOGRAPHY

INTRODUCTION
 There is much interest and activity in dentistry today with dentin bonding
agents.
 In the modern society, aesthetics has become a major concern for every
individual .Thus most of us desire for a perfect set of teeth.
 Therefore, teeth that have been deformed or ravaged by dental diseases
need to be restored to their natural form and colour.
 Moreover, the classic concepts of tooth preparation advocated in the early
1900s have changed dramatically.

 Now more focus is laid upon conservative approach to the tooth
preparation.
 Therefore the introduction of adhesive restorative materials has reduced
the need for an extensive tooth preparation.
 In order to successfully accomplish this, dentin bonding systems have
been introduced which bond the composite resin to the tooth structure.

DEFINITION
 Adhesion is derived from Latin 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 and Materials)

 Thus for the process of adhesion to occur , we need to understand the role
of following components:
 ADHESIVE
 ADHEREND
 ADHESIVE STRENGTH

 ADHESIVE is defined as a material , frequently a viscous fluid that
joins two substrates together by solidifying , resisting separation &
transferring a load from one surface to the other.
 ADHEREND is defined the surface to which an adhesive adheres.

 ADHESIVE STRENGTH is the measure of the load-bearing capacity of an
adhesive joint.
 Therefore the development of resin based restorative material has opened
new vistas to a more conservative approach to caries management.

MECHANISM OF ADHESION:
MECHANICAL
ADSORPTION
DIFFUSION
COMBINATION

INDICATIONS FOR ADHESIVE DENTISTRY
 Restoration of class 1,2,3,4,5,6 carious lesions
 Change the shape & colour of anterior teeth(using full or partial veneer )
 Seal pits and fissures
 Bond orthodontic brackets
 Desensitize exposed root surfaces
 Bond amalgam restorations to tooth
 Bond fractured segments of anterior teeth.
 Bond pre-fabricated fibre or metal posts and cast posts.
 Seal root canals during endodontic therapy.

ENAMEL ADHESION
 In 1955,Michael Buonocore described a clinical technique that used a diluted phosphoric acid to
etch the enamel surface to provide retention of unfilled, self-cured acrylic resins.
 The resin would mechanically lock to the microscopically roughened enamel surface, forming
small "tags" as it flowed into the 10-µm to 40-µm deep enamel microporosities and then
polymerized.
 The first clinical use of this technique was the placement of pit and fissure sealants.
 The formation of resin micro tags within the enamel surface is the basis of RESIN-ENAMEL
ADHESION.
 The steps involved are:

 Acid etching transforms smooth enamel into an irregular surface & increases its free surface
energy
 Application of a fluid resin based material to the irregular etched surface , facilitates
penetration of the resin into the surface aided by capillary action
 Monomers in the material are polymerised and the material becomes interlocked with the
enamel surface.

ETCH PATTERN
 Enamel etching leads to the following types of micro morphological
patterns:
 TYPE 1 ETCH PATTERN-dissolution of prism cores without involvement of
prism peripheries.
 TYPE 2 ETCH PATTERN-PERIPHERAL ENAMEL IS DISSOLVED , but
the cores are left intact.
 TYPE 3 ETCH PATTERN-it is less distinct than the other two patterns.

ETCHANT CONCENTRATION
 Buonocore used 30-40% phosphoric acid.
 Currently,37% phosphoric acid in gel form is used.
 Silverstone found that the application of 30-40% phosphoric acid resulted
in a very retentive enamel surface.
 >40% - Calcium salts are less dissolved - ETCH patterns with
poorer definition.
 <27% - Formation of dicalcium phosphate dihydrate -
cannot be easily removed by rinsing.

ETCH TIME
 Currently, an etching time of 15 seconds is used.
 An etching time of 60 seconds originally was recommended for
permanent enamel using 30-40% phosphoric acid.
 However , studies show that a 15 second etch resulted in a similar
surface roughness as that provided by a 60 second etch.

Phosphoric acid is said to be a more aggressive acid,so alternative etchants have
been suggested:
 EDTA (24%; ph=7)
 Citric acid
 Tannic acid
 Maleic acid
 Polyacrylic acid
ALTERNATE ETCHANT SYSTEMS:
 Lasers
 Air abrasion-Al2O3 particles

LASERS
 Adhesion to dental hard tissues after Er:YAG laser etching is inferior to that
obtained after conventional acid etching.
 Enamel and dentin surfaces prepared by Er:YAG laser etching show
extensive subsurface fissuring that is unfavorable to adhesion.
(J Prosthet Dent 2000;84:280-8.)
 Adhesion to laser-ablated or laser-etched dentin and enamel was inferior
to that of conventional rotary preparation and acid etching.
( Dental Materials (2005) 21, 616–624)

Figure 1 Scanning electron microscopic images of dentin: (A)
rotary-prepared and acid-etched (3500!),
(B) laser-prepared (9000!), and (C) laser-prepared and then acid-
etched (3500!).
(Fig. 1A) revealed a smoothsurface with tubule orifices
devoid of smear plugs.
The intertubular dentin is undisturbed.
In contrast, SEM of a cross-section of
laser-ablated, laser-etched dentin showed a highly
irregular surface and fissuring. Areas of poor hybridization
between composite and dentin suggest poor hybridization,
or no hybridization.
Laser-prepared dentin revealed surface scaling and
flaking, along with peritubular cuffing (Fig. 1B). Acid-
etching after
laser ablation appeared to decrease some of the surface
scaling and flaking (Fig. 1C).

Figure 3 Separation of resin adhesive and
unaffected subsurface dentin from laser-
ablated, then acid-etched dentin.
Laser ablated,acid-etched dentin
demonstrated areas of detachment
From both the resin adhesive and the
unaffected subsurface dentin (Fig. 3).

SEM photographs of 37% orthophosphoric acid, 10% maleic
acid, and Er,Cr:YSGG hydrokinetic laser-treated enamel are
shown in Figure 4.
The enamel surface etched with 2 acid solutions and a laser
system showed different results according to Silverstone’s10
etching patterns.
• The 37% orthophosphoric acid removed the periphery core
material but left the prism core relatively unaffected (type II),
producing a very rough enamel surface.
• The 10% maleic acid treatment resulted in preferential
removal of prism core material and left the periphery intact
(type I).
• Er,Cr:YSGG hydrokinetic laser treated enamel showed a
more random etching pattern in which adjacent areas of tooth
surface correspond to types I and II, mixed with regions where
the pattern could not be related to prism structure. There was
no recrystallization or melting observed

BOND STRENGTH
 Shear bond strength of composite to phosphoric acid etched enamel
exceeded 20 Mpa.
 According to studies,a minimum of 17-21MPa of bond strength is needed
to prevent the disruption of the bond between the tooth and composite.

DENTIN ADHESION
 Bonding to dentin is challenging & difficult.
 Adhesion to dentin occurs by mechanical method,chemical or both.
 But the main method is by penetration of adhesive monomers into collagen
fibrils which are exposed post acid etching.
 Structural differences exist between enamel & dentin.
 Therefore the following reasons account for challenges faced in dentin
adhesion:
 STRUCTURE OF DENTIN
 SMEAR LAYER
 STRESSES AT RESIN-DENTIN INTERFACE

STRUCTURE OF DENTIN
 Enamel contains 90% of hydroxyapatite crystals whereas dentin has only
50% and the rest is constituted by water(25%) and type I collagen(25% by
volume).
 Dentinal tubules exert pressure of 25-30mmHg, thus creating decreased
stability of bond between composite resin and dentin.
 The number of dentinal tubules decreases from about 45000 near the pulp
to 20000 near DEJ

 Also the tubule diameter decreases from 2.37µm to 0.63µm near DEJ.
 Adhesion can also be affected by remaining dentin thickness(RDT) as
bond strength is greater for superficial dentin and its lesser for deeper
dentin

WHAT IS SMEAR LAYER?
 It is the residual organic or inorganic components formed when a tooth is
prepared using a bur or other instrument.
(Sturdevant’s Art & Science of operative dentistry,4th edition)
 It is 1-10 µm thick .

 COMPOSITION OF SMEAR LAYER:
 According to SEM studies done by Shulien TM(1988),it consists of:
 Small particles of mineralized collagen matrix
 Inorganic tooth preparation
 Saliva
 Blood
 Bacteria
 According to branstroem,the organic component consisted of coagulated
proteins from collagen denatured by frictional heat of cutting.

 Therefore optimal bonding can occur by:
A. Removal of smear layer by using etch and rinse adhesives.
B. Incorporation of smear layer into bonding layer by self-etch adhesives
Complete removal of smear layer increases the dentin permeability by 90%.

 STRESSES AT THE RESIN-DENTIN INTERFACE:
 As composites polymerize,shrinkage occurs leading to stresses upto
7MPa.
 When the composite is bonded only to one surface,stresses are relieved
by flow from the unbended surface.
 Davidson et al. postulated that minimum bond strength of 17-20 MPa to
enamel and dentin is needed to resist contraction forces of resin composite
materials.
 In the present study, both the self-etching adhesives showed optimal bond
strength values greater than 20 MPa for both uncontaminated and
contaminated dentin.

DENTINE BONDING AGENTS
 It is defined as ”a thin layer of resin applied between conditioned dentin and resin
matrix of a composite.”
 The term dentine bonding agents is no longer relevant as current bond agents bond to
enamel and dentine.
 Due to acid –etching ,micro leakage or loss of retention is not a hazard at the resin-
enamel interface but its encountered at the resin-dentine interface.
 Due to the differences in the composition of enamel and dentine,developing agents
that will adhere to dentine was challenging due to the following reasons:
 The high water content interferes with bonding.
 Presence of a smear layer on the dentine surface.

 Therefore the bonding agent should be hydrophilic to displace the water
,permitting it to penetrate the porosities in dentine and react with the
inorganic/organic components.
 But, restorative resins are hydrophobic, therefore the bonding agent should
contain both hydrophilic and hydrophobic components.
 The hydrophilic part bonds with either calcium or collagen whereas the
hydrophobic part bonds with the restorative resin.

CONDITIONING OF DENTIN
 It is the etching of dentin surface with acids or calcium chelators.
 So, when acid is applied to it, dissolution of hydroxyapatite crystals in
intertubular dentin and outer surface of peritubular dentin occurs
 Ultimately, the smear layer gets removed and collagen fibrils are exposed.
 Materials used are: 37% phosphoric acid
 nitric acid
 citric acid
 EDTA(ethylene diamine tetra-acetic acid)

DURATION OF ETCHING ON DENTIN
Ideal duration is 15-20 seconds.
Increased duration: greater collapse
of collagen due to denaturation.
Decreased monomer infiltration.
Decreased duration: insufficient
depth of etching.

PRIMING OF DENTIN
 It is the process of applying primers to the etched/conditioned dentin
surface to improve the diffusion of the adhesive resin into moist and
demineralized dentin
 Primer solution is a mixture of monomers with hydrophilic and hydrophobic
components dissolved in organic solvent
 Priming agents are HEMA(hydroxyethyl methacrylate) and 4-META(4-
methacryloxyethyl trimellitae anhydride)

Acid washing / rinsing
Removes smear layer
Dissolves HA
Drying shrinks remaining
Collagen polymer molecules
Rehydration / priming
Swells collagen
Mechanism of dentine bonding

Monomer penetration
Mechanism of dentine bonding
Monomer polymerisation
And collagen entanglement

CLASSIFICATION
1. HISTORICAL STRATEGIES
 FIRST GENERATION(1965)
 SECOND GENERATION(1978)
 THIRD GENERATION(1984)
2. CURRENT STRATEGIES
 ETCH & RINSE ADESIVES
i. THREE STEP-ETCH &RINSE ADHESIVE(FOURTH GENERATION)
ii. TWO STEP –ETCH & RINSE ADHESIVE(FIFTH GENERATION)
 SELF ETCH ADHESIVES
 TWO COMPONENT –SELF ETCH ADHESIVE(SIXTH GENERATION)
o TWO STEP-TWO COMPONENT –SELF ETCH ADHESIVE
o ONE STEP –TWO COMPONENT - SELF ETCH ADHESIVE
 SINGLE COMPONENT-ONE STEP-SELF ETCH ADHESIVE(SEVENTH
GENERATION)

 Current strategies
 ETCH & RINSE ADESIVES SELF ETCH ADHESIVES
 THREE STEP-ETCH &RINSE ADHESIVE TWO STEP –ETCH & RINSE ADHESIVE
(FOURTH GENERATION) (FIFTH GENERATION)
TWO COMPONENT –SELF ETCH ADHESIVE SINGLE COMPONENT-
ADHESIVE(SEVENTH
( SIXTH GENERATION ) ( SEVENTH GENERATION)
TWO STEP-TWO COMPONENT –SELF ETCH ADHESIVE
ONE STEP –TWO COMPONENT - SELF ETCH ADHESIVE

 BASED ON MODERN ADHESION STRATEGY:
Van Meerbek et al(2001) suggested a classification based on adhesion strategy.
TOTAL ETCH SELF ETCH
TWO STEP MILD
THREE STEP ADHESIVES MODERATE
INTERMEDIARY STRONG
TYPE OF ADHESIVE STEPS INVOLVED
ETCH AND RINSE
ADHESIVES
THREE STEP ADHESIVE:FOURTH GENERATION
TWO STEP ADHESIVE:FIFTH GENERATION
SELF ETCH ADHESIVES
TWO STEP ADHESIVE:SIXTH GENERATION
ONE STEP ADHESIVE:SEVENTH GENERATION

 BASED ON THE TREATMENT OF SMEAR LAYER:
 Smear layer modifying
 Smear layer removal
 Smear layer dissolving

DECADE BONDING AGENT FEATURES
1960s
1970s
FIRST GENERATION
SECOND GENERATION
• DENTIN ETCHING WAS CONTRAINDICATED
• ADHESION WAS TO SMEAR LAYER
• WEAK BOND STRENGTH
1980s THIRD GENERATION • ETCHING ENAMEL & DENTIN
• PRIMING-A SECOND STEP WAS DONE
• BETTER BOND STRENGTH
EARLY 1990s FOURTH GENERATION • TOTAL ETCH CONCEPT WAS INTRODUCED
• WET BONDING & HYBRID LAYER CONCEPTS
INTRODUCED
• MULTIPLE TECHNIQUE SENSITIVE CLINICAL STEPS
MID 1990s FIFTH GENERATION • PRIMER & ADHESIVE COMBINED IN ONE BOTTLE
• HIGHER BOND STRENGTHS
LATE 1990s SIXTH GENERATION • INTRODUCTION OF SELF-ETCHING PRIMERS
• POST OPERATIVE SENSITIVITY WAS REDUCED
• LOWER BOND STRENGTHS
EARLY 2000s SEVENTH GENERATION • ALL IN ONE/ONE STEP BOND CONCEPT
INTRODUCED
• BOND STRENGTH LOWER THAN 4TH & 5TH
GENERATIONS

4-META Methacryloxy ethyl trimellitic
anhydride
NPG-GMA N-Phenylglycine glycidyl methacrylate
UDMA Urethane dimethacrylate
TEGDMA Triethyleneglycol dimethacrylate
MDPB 10-Methacryloyl oxydodecyl pyridinium
bromide
MDP 10-Methacryloyl oxydecyl dihydrogen
phosphate
PENTA Dipentaerythritol pentaacrylate
monophosphate
TYPE OF RESIN EXPANSION
Bis-GMA Bisphenol A glycidyl methacrylate
HEMA 2-hydroxyethyl methacrylate

 Most products use a three-component system consisting of a conditioner, primer, and
adhesive.
 1. CONDITIONER (CLEANSER, ETCHANT) –
 weak organic acid (e.g., maleic acid),
 a low concentration of a stronger inorganic acid (e.g., phosphoric or nitric acid)
 a chelating agent (e.g., EDTA).

 MAIN ACTIONS:
 Alters or removes the smear layer.
 demineralizes peritubular and intertubular dentin
 exposes collagen fibrils --demineralizes up to a depth of 7.5 microns.
 peritubular dentin is etched more deeply than the intertubular dentin
increases dentin permeability.

 PRIMER
 bifunctional monomer in a volatile solvent such as acetone or alcohol
 examples of HEMA (hydroxyethyl methacrylate),
NMSA (N-methacryloyl-5- aminosalicylic acid),
NPG (N-phenylglycine),
PMDM (pyromellitic diethylmethacrylate), and
4-META (4- methacryloxyethyl trimellitate anhydride).

 MAIN ACTIONS:
 Links the hydrophilic dentin to the hydrophobic adhesive resin
 Promotes infiltration of demineralized peritubular and intertubular dentin
 increases wettability of the conditioned dentin surface

 ADHESIVE (BONDING RESIN):
 It is an unfilled or partially-filled resin; may contain some component of the primer (e.g.,
HEMA) in an attempt to promote increased bond strength.
 MAIN ACTIONS:
 Combines with the primer s monomers to form a resin-reinforced hybrid layer ( resin-dentin
interdiffusion zone ) 1 to 5 microns thick.
 Forms resin tags to seal the dentin tubules

FIRST GENERATION DENTIN BONDING AGENT
 It consisted of surface active co-monomer NPG-GMA(N-phenylglycine
glycidyl methacrylate)
 MECHANISM OF ACTION:
 This co-monomer could chelate with calcium on the tooth surface to
generate chemical bonds of resin to calcium.
 Example:
 Cervident(S S White burs,Lakewood)

 Clinical result:
 It had poor bond strength of 2-3MPa.
 Therefore when used to restore noncarious cervical lesions without
mechanical retention.

SECOND GENERATION DENTIN BONDING
AGENT:
 Introduced in 1978.
 They were based on phosphorous esters of methacrylate derivatives.
 Adhesion was by means of ionic interaction between the negatively charged
phosphate groups & positively charged calcium in the smear layer.
 Advantage:
 Bond strength was 3 times higher than the earlier ones.
 Disadvantage:
 Bond strength was still lower around 5-6 Mpa.
 Clinical failure due to the bonding instability in the wet oral environment & their
primary bonding to the smear layer and not the dentin.

 ADVANTAGE:
 Bond strength was 3 times higher than the earlier ones.
 DISADVANTAGE:
 Bond strength was still lower around 5-6 Mpa.
 Clinical failure due to the bonding instability in the wet oral environment &
their primary bonding to the smear layer and not the dentin.

 EXAMPLES:
 Clearfil Bond System(Kuraray,Japan)
 Scotchbond(3M ESPE)
 Bondlite(Kerr Corporation.CA)
 Prisma Universal Bond(Dentsply)

THIRD GENERATION BONDING AGENT:
 It was a phosphate based material containing HEMA and a 10-carbon
molecule 10-MDP(10-methacryloyloxy decyl dihydrogen phosphate)
 These were introduced with Clearfil New Bond in 1984.
 The concept of phosphoric acid etching of dentin before the application of
a phosphate ester type of bonding agent was put forward by FUSAYAMA
et al in 1979

 Most of the other III generation bonding agents were designed not to
remove the smear layer but only to modify it and therefore allow the
penetration of acidic monomers like pheny-P or PENTA(dipentaerythritol
penta-acrylate monophosphate)
 EXAMPLES:
 Clearfil New Bond(Kuraray)
 Scotchbond 2(3M ESPE)

COMPOSITION OF SOME III
GENERATION
DENTIN BONDING AGENTS
Adhesive
system
Etchant Primer Adhesive Bond
strength
Scotch Bond
2
2.5% maleic
acid + 55%
HEMA
HEMA Bis GMA 8.8 Mpa
Tenure
Oxalate bonding
system
aluminium
oxalate in
2.5% nitric
acid
NPG-GMA. BisGMA,
TEGDMA
15 Mpa
This generation attempted to deal with both the smear layer and dentinal fluid,
with following 2 approaches:
i. Smear layer modification to improve its properties.
ii. Remove s.layer without disturbing the smear plugs that occlude dentinal tubules.

CLASSIFICATION
 SELF ETCH ADHESIVES
 SINGLE COMPONENT-ONE STEP-SELF ETCH ADHESIVE(SEVENTH GENERATION)

CURRENT STRATEGIES FOR RESIN-DENTIN
BONDING
1. ETCH AND RINSE ADHESIVE:
The smear layer is considered to be an obstacle that must be removed to
permit resin bonding to dentin.
The next generation of dentin adhesives was introduced for use on acid –
etched dentin.
The clinical technique involves simultaneous application of an acid to enamel
& dentin.This was called as total-etch technique.

application of acid to dentin results in complete or partial removal of smear layer and
demineralization of dentin
Intertubular & peritubular dentin are demineralised,thus exposing collagen fibres & increasing
microporosity of intertubular dentin
7.5µm of dentin is demineralised
Primer increases the free surface energy of dentin
Formation of resin tags and hybrid layer.

 MOIST BONDING TECHNIQUE WITH ETCH AND RINSE ADHESIVE
• This was given by Kanca & Gwinett in 1990.
• Excess water on the substrate that is the tooth surface is not indicated due to the
following reasons:
• Swelling of collagen occurs leading to the decrease in the space available for resin
penetration
• Secondly, it dilutes the primer.
• Thirdly, when priming is done in such conditions, phase separation of hydrophobic and
hydrophilic components occur leading to blister & globule formation at the resin-dentin
interface.
• Thus these water blisters may compress when the restoration is under,forcing dentinal
fluid towards pulp and causing post-operative sensitivity.

 How wet or dry should the dentin be?
 It should be hydrated that is clinically glistening and moist.
 How to achieve it?
 After etching and rinsingblot the excess water dry with a sponge & which
shoulbe touched to the surface of water and not pressed against dentin.

 Why is complete drying of dentinal surface contraindicated?
 Vital dentin is moist.Therefore drying the dentin with air would cause
collapse of dentinal collagen fibrils and thus leading to its shrinkage.
 The interfibrillar space should be left open and hydrated for effective resin
infiltration.

SEM of dentin that was acid etched with 37% phosphoric acid for 15s & rinsed
with water and then briefly air dried.there is disappearance of spaces between
collagen fibrils in top 1µm of demineralized zone that extends 5µm.although liquid
monomers can permeate the tubules,it cannot pass through the spaces between
collagen fibrils in intertubular dentin. TL-dentinal tubule.

SEM of dentin that was kept
moist after rinsing off etchant.
The abundant intertubular
porosity serves as a pathway for
the penetration of the dentin
adhesive . T, dentinal tubule.

Scanning electron micrograph of
dentin collagen after acid etching
with 35% phosphoric acid.Dentin
was air dried.
The intertubular porosity
disappeared due to collapse of
collagen secondary to the
evaporation of water.

THREE STEP:ETCH&RINSE
ADHESIVES(FOURTH GENERATION)
IT CONSISTS OF
ETCHANT PRIMER ADHESIVE

 Here three components came into being:
 Phosphoric acid etchant(in gel form)
 Primer –it consisted of hydrophilic monomers in ethanol , acetone or water.
 Primer is a bifunctional molecule having a hydrophilic and a hydrophobic
part.the former attaches to tooth whereas the latter attaches to composite
resin.
 Examples:HEMA
NTG-GMA
PENTA

 Bonding agent:
 It consists of unfilled or filled resin which may be BisGMA(Bisphenol
glycidyl methacrylate),UDMA(urethane dimethacrylate) with TEGDMA &
HEMA(2-hydroxyethyl methacrylate).
 Thus after the application of primer and bonding agent to etched surface
aids in their penetration into intertubular dentin to form a resin-dentin inter
diffusion zone called HYBRID LAYER which was introduced by
Nakabayashi in 1982.

 ADVANTAGES:
 Higher bond strength of 17-24MPa.
 They show reliable and consistent results.
 DISADVANTAGES:
 Technique sensitive
 Time consuming procedure
 Over wetting or over drying of dentin may occur

• BRAND NAMES-
• All Bond 2 & All Bond 3
• Optibond FL(Kerr Corporation)
• Adper Scotchbond Multi-purpose(3M ESPE)
• BOND STRENGTH-
• 17-30 Mpa.

 CLINICAL STEPS INVOLVED:
 STEP1:application of etchant gel(37% phosphoric acid) for 15 seconds .
 STEP2:rinse the etchant thoroughly and blot dry the substrate
(moist bonding technique)
 STEP3:application of primer (bottle 1) on the substrate.
 STEP4:application of adhesive(bottle 2)on the tooth substrate.
 STEP5: light cure .

1st step:
-Total etching(removal of
smear layer)
Leaving free minerals on
surface
-Rinse surface
-Without drying of surface
(residual water left)
2nd step :
adding primer
3rd step:
Adding adhesive resin &
then composite
Composite
Smear layer
Residual
water
Primer
Adhesive resin

WHAT IS HYBRID LAYER?
 DEFINITION
 “The structure formed in the dental hard tissue by demineralization of the
surface and the sub-surface followed by infiltration of monomers &
subsequent polymerization.”
( Nakabayashi,1982)
 It is a hybrid combination of the above two. It is a process which creates a
molecular level interfacebetween dentin and composite resin.

ZONES
TOP LAYER MIDDLE LAYER BASE
TOP LAYER :loosely arranged collagen fibrils directed towards adhesive resin.
MIDDLE LAYER: collagen fibrils separated by electron lucent spaces(10-20nm)
represent areas in which HA crystals have been replaced by resin due to
hybridization.
BASE : partially demineralized dentin.

TWO STEP :ETCH & RINSE ADHESIVES (FIFTH
GENERATION)
 This was developed to simplify the procedures involved in bonding.
 Therefore , the primer and the bonding agent is present in a single bottle.
 COMPONENTS:
 ETCHANT GEL + PRIMER & ADHESIVE

It consists of
BOTTLE I BOTTLE II
(Etchant+Primer) (Adhesive)

BONDING TO DENTIN USING A SELF-ETCH PRIMER

 STEPS INVOLED ARE:
 STEP1:application of etchant gel.
 STEP2:rinse the etchant thoroughly and blot dry the substrate
(moist bonding technique)
 STEP3:application of primer and adhesive (single bottle)
 STEP4:light cure .
 BRAND NAMES:
 Prime & Bond NT(Dentsply)
 Adper single bond2
 ExciTE(Ivoclar,Vivadent)
 One coat Bond
 XP Bond

CLASSIFICATION
 SINGLE COMPONENT-ONE STEP-SELF ETCH ADHESIVE(SEVENTH
GENERATION)

SELF-ETCH ADHESIVES
 They are defined as “bonding systems which dissolve the smear layer and
create porosities in the underlying dental substrates without needing an
extra conditioning agent(eg:phosphoric acid) to be applied in a single step.
(Quintessence International,vol(8), nov-dec2013)
 No separate etching step is needed.
 ADVANTAGES:
 Decrease in the number of steps
 Less technique sensitive.

 The self-etching approach has been proposed in an effort to simplify the
dentin/enamel bonding systems.
 These materials combine tooth surface etching and priming steps into one
single procedure.
 The elimination of separate etching and rinsing steps simplified the
bonding technique and has been responsible for the increased popularity
of these systems in daily practice33

 Based on the acidity of self-etch primers & adhesives, they are classified
as:
 Weak- pH-2
 Medium pH-1.5
 Strong pH≤1
 Most commonly pH ranges from1.3-2.7

SELF-ETCH ADHESIVES
2 COMPONENT SELF-ETCH ADHESIVES 1 COMPONENT SELF-ETCH
ADHESIVES
(VI GENERATION) (VII GENERATION)
2 STEP & 2 COMPONENT I STEP BUT 2 COMPONENT

VI GENERATION BONDING AGENT
1. 2 STEP : 2 COMPONENT SELF-ETCHING ADHESIVES:
(NONRINSING CONDITIONERS OR SELF PRIMING ETCHANTS)
MECHANISM OF ACTION:
 These acidic primers contain phosphonated resin molecule that performs
two function:
 Etching and priming of enamel
 Incorporating smear plugs into resin tags.

 Steps involved are:
 Application of bottle I(etchant +primer)
 After 10 s, application of bottle2 on tooth surface
 Light cure
 BRAND NAMES:
 Clearfil SE Bond(Kuraray,Japan)
 AdheSE(Ivoclar-Vivadent)
 Optibond Solo Plus Self-etch(Kerr Corp)

2. ONE STEP:TWO COMPONENT-SELF-ETCH ADHESIVE:
 consists of- BottleI +Bottle II
 Bottle I:conditioner +primer
 Bottle II: adhesive resin
 Both have to be mixed prior to application on tooth surface.
 BRAND NAMES:
 Xeno III(Dentsply)
 One up bond(Tokuyama)
 Prompt L bond(3M ESPE)

 Self etching primers are acidic in nature, leading to its penetration along
the aqueous channels found in the smear layer and widening them.
 These offer a simpler clinical step when compared to the tota;l etch
adhesive systems.
 self etching primers contain acidic esters like HEMA,TEGDMA,MDP.
 These primers are similar to those found in third generation dentin bonding
systems, the only difference being that in the latter ones only milder acids
were used leading to inability to etch beyond the smear layer.

 In the sixth generation dentin bonding systems, acidic monomers like 4-
MET and 10-MDP are used ,thus dissolving the smear layer.
 When the concentration of acidic monomers increasd from 5-10% wt %(III
generation dentin bonding agent) to 30-40% (VI generation dentin bonding
agent) and dissolved in 30-40% HEMA, pH-1-2 was developed which
aided in etching through smear layer.

 ADVANTAGES
 No etching needed, therefore possibility of over-etching or over-drying is removed
 Less technique sensitive.
 Self-etch adhesives are less likely to result in discrepancy between depth of demineralization
and depth of resin infiltration as both the processes are done simultaneously.
 Less time consuming
 DISADVANTAGES
 Decreased shelf life
 Incompatible with chemical cure composites.
 Self-etch adhesives that are currently available do not etch as efficiently as phosphoric acid,
especially if the enamel has not been instrumented.

 TYPE 2 ( TWO BOTTLE 1 STEP SYSTEM):
 Liquid A contains primer.
 Liquid b contains a phosphoric acid modified resin.
 Both are mixed before application.
 Eg:Xeno 3(Dentsply),Adper-prompt L-pop(3M).

SEVENTH GENERATION(early 2000s):
(SELF-ETCHING ADHESIVES)
 Here the etchant, primer and the adhesive resin are combined into one
bottle .
 In vitro studies have shown that tooth-restoration interface created when
using self etching adhesives do not eliminate the micro leakage and
bacterial penetration, which can lead to secondary caries.
 (Kakar S,Goswami M,nagar R.Dentin bonding agents-2 Recent trials.
World J Dent2012;3(1);115-118.

 ADVANTAGES OF VII GENERATION DENTIN BONDING AGENTS:
 Lesser application time
 Decrease in errors with each step.

 Examples are:
 iBond(Heraeus kulzer)
 G bond(GC)
 XenoIV(Dentsply)
 Clearfil S3(Curare)
 XenoV+
XenoV+

iBond
COMPONENT FUNCTION
UDMA
(urethane dimethacrylate)
MATRIX COMPONENT
ETCHING & CONDITIONING OF ENAMEL & DENTIN
BONDING TO COLLAGEN VIA HYDROGEN
BONDING
BONDING TO CALCIUM IONS VIA CHELATION
COMPLEXES
4-META
(4-methyloxyethyl trimellitic acid)
MATRIX COMPONENT
CROSS-LINKING
WATER SOLVENT FOR MONOMERS
PROVIDES WATER FOR ETCHING
CAMPHORQUINONE PHOTOINITIATORS
GLUTARALDEHYDE DISINFECTANT/DESENSITIZER
STABILIZERS

How is iBond applied?
1. Isolate tooth from saliva contamination during adhesive procedure
2. Clean the tooth prepation,removing all debris with water.
3. Saturate the microbrush with iBond liquidfrom the bottle or single dose
vial.
4. Apply 3 consecutive coats of iBond to enamel & dentin
5. Use gentle air pressure to remove excess solvent
6. Cure for 20s with curing light
7. Place the composite resin.

 Both the hydrophilic and the hydrophobic components are mixed in this system.
 Though this simplifies the clinical steps,it has following shortcomings:
 Due to the complex nature of this solution,they are more prone to phase separation.
 It forms droplets within the adhesive layer.
 This adhesive layer acts as a semi-permeable membrane permitting bi-directional water
currents.
 Thus these bonding agents show much reduced bond strength when compared to the
fourth,fifth,and sixth generation of bonding agents.

 Advantages:
 Most time efficient application procedure.
 Unidose application,which prevents cross-contamination.
 Simultaneous demineralisation & resin penetration.
 Less sensitivity to dentin wetness conditions.
 Disadvantages:
 Reduced shelf life.
 Less sealing capacity.
 Least bond strength.
 Incompatibility with auto/chemical curing composites.

ONE COAT 7 BOND.
 7TH generation ,one component.
 Light cured self etching resin.
 High performance on any surface.
 Has a fast application in 35 seconds.
 On wet surfaces maintains uniform composition, producing an
effective bond.

RECENT ADVANCES :
UNIVERSAL ADHESIVE
 In 2012, the term “universal adhesive” has been given several definitions
which are:
a)Can be used in total-etch, self-etch, and selective etch techniques;
b)Can be used with light-cure, self-cure, and dual-cure materials (without the
separate activators);
c)Can be used for both direct and indirect substrates;
d)Can bond to all dental substrates, such as dentin, enamel, metal, ceramic,
porcelain, and zirconia.

 In November 2011, a new “ScotchBond Universal” was discovered.
Which needs a separate self-cure activator or a special amine-free dual-
cure cement when in use with dual-cure or self-cure materials, hence not
a truly “universal” adhesive.

 In March 2012, a “All-Bond Universal” was discovered, which can be
used in:
i.total-etch, self-etch and selective etch techniques,
ii.can be used with any dual-cure, self-cure and light-cure
materials without the need of a separate activator,
iii.can also be used for both direct and indirect substrates, and
can bond with any dental substrates.
 All-Bond Universal is the first truly “universal adhesive”.

IS FUTURABOND DC-THE EIGTH
GENERATION
BONDING AGENT?

BASED ON THE TREATMENT OF SMEAR LAYER
SMEAR LAYER SMEAR LAYER SMEAR LAYER
MODIFYING REMOVAL DISSOLVING

SMEAR LAYER
 It was first suggested by Skinner in 1961.
 Coined by Boyde in 1963.
 0.5-2µm thick, granular
 Smear plugs…1-10µm

WHY IS THE PRESENCE OF SMEAR LAYER
DETRIMENTAL TO BONDING?
 It is a weak attachment to dentin and is brittle
 so it can be easily dislodged & prone to cohesive failure.
 Therefore to overcome this, etch & rinse adhesive was developed.

SMEAR LAYER REMOVAL
 DRAWBACK OF COMPLETE REMOVAL OF SMEAR LAYER:
Increases dentin permeability and flow of the dentinal fluid
Thus diluting the bonding agent
 Examples:
 IV & V generation dentin bonding agents.

SMEAR LAYER MODIFYING
 Examples:
 II & III generation dentin bonding agents.
 Incorporation of smear layer inhibited proper bonding and resulted in loss
of bond strength.

SMEAR LAYER DISSOLVING
 Self-etching adhesives dissolve and include the smear layer in the
hybridization process.
 BASED ON Ph
STRONG INTERMEDIARY MILD
(<1) (1-2) (≅ 2)

Suresh Chandra et al.Comparative evaluation of self-etching
primers sixth, fourth& fifth generation dentin bonding systems
on carious and normal dentin.J Conser Dent2008;11(4):154-158
 Study comparing bond strengths of total etch and self etch primer to
carious affected and normal dentin.
 Result- higher bond strength with normal dentin than caries affected dentin
 Discussion: self etching primers needed highest mean shear load to
fracture followed by V, IV generation bonding agents
 Self etching primers superficially demineralize normal dentin by dissolving
fibrils

 Thus aiding in monomer infiltration.
 Later the dentin is not washed therefore shrinkage of collagen is avoided.
 According to the study the bond strength of self etching primers > fourth &
fifth .

BONDING EFFICACY OF VI AND VII
GENERATION BONDING AGENTS
 Manjula Nair, Joseph Paul et al. comparative evaluation of bonding
efficacy of VI and VII generation dentin bonding agents: an invitro study. J
Conserv Dent 2014; 17(1):27-30.
 Aim: to compare shear bond strength of VIth and VII dentin bonding
agents.
Materials
used
VI DBA
ADPER
SEPLUS
PH<1
XENO III PH-1.4
VII DBA
ADPER
EASY ONE
PH-2.3
XENO V

 Result:
VII>VI DBA
 Discussion:
 VI generation bonding agents have less bond strength to dentin due to high
acidity resulting in higher amount of demineralization.
 But the VII generation dentin bonding agents (mild self etch adhesives)
demineralise upto one µm only keeping residual hydroxyapatite still attached
to collagen.
 This 1µm is enough for micromechanical retention .

 The retention of hydroxyapatite within the hybrid layer acts as receptor for
chemical bonding.
 Therefore this leads to higher bond strength with mild self etch adhesives.
 So this is the cause for low bond strength with Adper SE Plus and Xeno III.
 Though according to this study VII generation has higher adhesive
property than VI, some studies contradict this.

Comparative evaluation of bonding efficacy of sixth,seventh
and eighth generation bonding agents:an in vitro study. Paul
Joseph et al.Int .Res. J Pharm.2013,4(9)
 The aim of the study was to compare In-vitro the micro tensile bond strength of sixth
generation (Clearfil SE Bond, Kuraray, Japan), seventh generation (Adper Easy One, 3 M
ESPE, Germany) and eighth generation ((Futurabond DC, Voco, Germany) dentin bonding
agents.
 Results:
 Futurabond DC, Voco, Germany>Clearfil SE Bond, Kuraray, Japan>Adper Easy One, 3 M
ESPE, Germany)

Figure 3: Specimens obtained after hard tis sue microtome sectioning Figure 4: Universal Testing Machine

CLINICAL APPLICATION OF SELF-ETCH
BONDING SYSTEMS
 Class V composite resin restoration using a
self-etch two step system
a) Application of self-etch primer.
b) Application of adhesive.
c) Completed Class V composite resin
restoration.

 ANTERIOR COMPOSITE RESTORATIONS(CLASS III,IV)

 POSTERIOR COMPOSITE RESIN RESTORATIONS
 Core build up restoration with light cured composite resin using two-step self-etch
bonding system.
a) After removal of defective amalgam restoration
b) Application of self-etching primer
c) Application of adhesive
d) Completed composite restoration in molars and the premolar

 RESTORATION OF PRIMARY TEETH
 Self-etch adhesives are an alternative to total etch systems.
 But ,the all in one adhesives should be used in combination with
compomers(polyalkenoic acid modified composite resins) & only in small
to medium sized cavities with adequate macroretention.
(Quintessence International, vol(8),nov-dec2013)

 CORE BUILD-UP WITH LIGHT-CURED COMPOSITE RESIN:
 CORE BUILD UP WITH FLOWABLE COMPOSITE….DEFECTIVE AMALGAM
RESTORATION…..TWO STEP SEA….FULL CERAMIC PARTIAL CROWN

EXAMPLE OF A SELF-ETCH TWO STEP BONDING SYSTEM
INCLUDING ACTIVATOR(ADHESE/ADHESE DC ACTIVATOR)
FOR COMBINATION WITH DUAL-CURED RESIN CEMENTS &
CORE BUILD-UP COMPOSITES

In the combined post & core technique,the same dual cured composite resin is used for adhesive
post cementation & as core material.
a. try in of FRC post.
b. application of self-etch primer-adhesive into root canal using endo-microbrush.
c.adhesively cemented FRC post with composite core build-up.
a
A.

 TREATMENT OF CERVICAL DENTIN HYPERSENSITIVITY
 PREVENTION OF ROOT SURFACE CARIES
 ADHESIVE CEMENTATION OF INDIRECT RESTORATION

MICROLEAKAGE
 DEFINITION
 It is the passage of bacteria and their toxins between restoration
margins and tooth preparation walls
 The presence of gaps at the resin-dentin interface leads to ingress of
bacteria.

 Therefore bonding the resin to a preparation with cavosurface margins in
enamel is the best way to prevent microleakage.
 Bacteria are able to survive & proliferate within the fluid filled marginal
gaps, thus leading to secondary caries.

NANOLEAKAGE
 It is the small porosities in the hybrid layer or at the transition between the
hybrid layer and the dentin that allow the passage of particles of silver
nitrate dye.
 Penetration of ammoniacal silver nitrate results in two patterns:
 Spotted pattern-in the hybrid layer of self-etch adhesives due to incomplete
resin infiltration.
 Reticular pattern-that occurs in the adhesive layer due to incomplete
removal of water from the bonding area.

NANOLEAKAGE UNDER ELECTRON MICROSCOPE.
Spotted pattern in the hybrid layer formed by one-step self-etch adhesive
Reticular pattern and water trees in adhesive layer formed by self etch adhesive

ANTIBACTERIAL PROPERTY OF DENTIN
BONDING
AGENTS
 The development of adhesive systems have enabled variable cavity
designs to preserve tooth structure and treatment of dental caries has
shifted from the traditional method to that with downsized cavities.
 Inspite of considerable improvement in the recent years , polymerization
shrinkage & the resultant contraction gaps in tooth restoration interface
continue to be a significant problem associated with composite resin
restorations.

 Thus cariogenic bacteria like Streptococcus mutans,Lactobacillus
acidophilus,Lactobacillus casei and Streptococcus salivarius can invade
along the microgaps and lead to secondary caries.
 Therefore it is imperial to provide resin based materials with antibacterial
activity.
 Imazato et al have reported the antibacterial property of MDPB
((methacryloyldodecylpyridinium bromide) which is monomer present in
the bonding agent.
 Also, acidic monomers like 10-MDP(10-methacryloyloxy decyl dihydrogen
phosphate) due to its inherent acidity has antibacterial property.

Amin S,Shetty HK,Varma RK,Amin V,Nair PM.Comparative
evaluation of antibacterial activity of total etch and self etch
adhesive systems:An ex vitro study.J Conser Dent 2014
;17:266-70
 The purpose of the study was to compare the antibacterial activity of total-
etch and self-etch adhesive systems against Sreptococcus mutans ,
Lactobacillus acidophilus , and Actinomyces viscosus through disk
diffusion method .Of all the materials tested, the antibacterial effects may
be related to the acidic nature of the adhesive systems.


Sampath PB, Hegde MN, Hegde P.Assessment of the
antibacterial properties of newer dentin bonding agents. An in
vitro study.Contemp Clin Dent 2011;2:165-9.
 The aim of this study was to evaluate and compare the antibacterial
activity on Streptococcus mutans using direct control test.The
incorporation of antibacterial agents into dentin bonding agents may
become an essential factor in inhibiting residual bacteria in the cavity.

Amin S,Shetty, HK,Varma et al. Comparative evaluation of antibacterial
activity of total etch and self etch adhesive systems:An ex vitro study.J
Conser Dent 2014 ;17:266-70
 Aim: The aim of this ex vivo study was to compare the antibacterial activity of total-etch and self-
etch adhesive systems against Streptococcus mutans, Lactobacillus acidophilus, and Actinomyces
viscosus through disk diffusion method.

Materials and Methods: The antibacterial effects of Single Bond (SB) and Adper Prompt (AP) and
aqueous solution of chlorhexidine 0.2% (positive control) were tested against standard strain of S.
mutans, L. acidophilus, and A. viscosus using the disk diffusion method. The diameters of inhibition
zones were measured in millimeters. Data was analyzed using Kruskal-Wallis test. Mann-Whitney U
test was used for pairwise comparison.

 Result: Of all the materials tested, AP(Adper Prompt) showed the
maximum inhibitory action against S. mutans and L. acidophilus. Aqueous
solution of chlorhexidine 0.2% showed the maximum inhibitory action
against A. viscosus. Very minimal antibacterial effect was noted for
SB(Single Bond).

Conclusion: The antibacterial effects observed for the tested different
dentin bonding systems may be related to the acidic nature of the
materials.

BIOCOMPATIBILITY
 Biological testing of DBA is a delicate and complex process.
 Unlike most dental materials, many dentin bonding systems are made up
of more than one material e.g. cleanser , primer , bonding resin etc.

• A very limited number of reports have been published on the
biocompatibility of the first generation. Which may be due to their
inferior physical properties.
• Van Leeuwen et al showed no severe reactions even in extremely
deep caries in their study.
1st generation.
• Most studies are carried out using Scotch Bond.
• It might have a adverse effect on pulp tissue when placed
in contact with vital tooth and proper pulpal protection was
recommended.
2nd generation.
• Tests showed that the bonding material as well as the
individual components were toxic.
3rd generation.

International endodontic journal.
Volume 44 number 9 september 2011.

*Aim *
To evaluate the genotoxicity of four different adhesives, Clearfil SE Bond,SL Bond, i
Bond and Clearfil Protect Bond and the primers of Clearfil SE Bond and Clearfil Protect
Bond.
*Results *
A significant increase (*P* < 0.001) compared to untreated controls in DNA damage was
observed with 'Clearfil Protect Bond' and 'Clearfil SE Bond' primer in human
lymphocytes at concentrations of 2.5 and 5.0 mg mL-1.
Clearfil Protect Bond and Clearfil SE Bond adhesives induced significant (*P* < 0.001)
DNA damage only at the higher concentration of 5.0 mg mL-1. No significant increase in
DNA damage was observed with SL Bond and i Bond.
Nosignificant DNA damage was observed with any dentine bonding agents at the lower
concentration of 1.25 mg mL-1.
*Conclusions *
'Clearfil Protect Bond' and 'Clearfil SE Bond' primers/adhesives increased DNA damage
in human peripheral lymphocytes in high doses.

CLINICAL FACTORS AFFECTING ADHESION
 Flow of saliva and/or blood contamination
 Moisture contamination from handpiece or air water syringe
 Oil contamination of handpieces or air-water syringes
 Fluoride content of teeth
 Location and size of dentinal tubules
 Presence of plaque,calculus,extrinsic stains or debris
 Presence of bases or liners on prepared teeth
 Tooth dehydration
 Presence of residual intermediary cements

BONDING TO AMALGAM
 Bonding of amalgam restoration to tooth is still a debatable topic.
 The use of adhesive systems beneath amalgam restoration reduces or
prevents microleakage, makes cavosurface angle less susceptible to
demineralization when compared to varnish.
 There is reduction in sensitivity and more conservative cavity preparation
can be achieved when amalgam is bonded to tooth.

 Staninec M (1989) showed that retention with amalgam bonding is equal
to or superior to traditional means of mechanical retention.
 Tig IA, Fodor O, Moldovan M et al (2005) noticed that at higher
magnification, teeth restored with unbonded amalgam had more spaces
and artifacts at the amalgam-tooth structure interface when compared with
those

Failures 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.
Affected by –
 dentin wetness
 tooth flexure
 arch
 size of lesion
 substrate
 material factors

CONCLUSION
In today’s era, numerous improvements in materials and
procedures have been made to meet the growing aesthetic
demands of the patients.
 In all the aesthetic restorations a bonding step is
involved to ensure durability and reliability.

 Thus the ideal bonding system should be biocompatible,
bond perfectly to enamel and dentin, have sufficient
strength to resist to failure as a result of masticatory forces,
have mechanical properties close to those of tooth, and be
resistant to degradation in oral environment and easy to
use.

BIBLIOGRAPHY
 STURDEVANT'S ART & SCIENCE OF DENTISTRY-4TH, 5TH & 6TH
EDITION
 PHILLIPS-SCIENCE OF DENTAL MATERIALS...11TH EDITION
 TOOTH COLORED RESTORATIVES-PRINCIPLES AND
TECHNIQUES..9TH EDITION
 PICKARD'S MANUAL OF OPERATIVE DENTISTRY...8TH EDITION
 TEXTBOOK OF OPERATIVE DENTISTRY-SUMEETHA
SANDHU..1ST EDITION
 MATERIALS USED IN DENTISTRY….S.MAHALAXMI

 M.Bourbia, D.Ma, D.G Cvitkovitch et al.Cariogenic bacteria degrade
dental resin composite and adhesives.J Dent Res 92(11):989-994,2013.
 Bernd Haller et al.Quintessence International,1,nov-dec2013.
 .Arora R, Rao MH. Comparative evaluation of antibacterial effects of four
dentin bonding systems: An in vitro study.J Conserv Dent 2013;16:466-
70
 2.Taha MY, Al-Shakir NM, Al-Sabawi NA. Antibacterial effect of Dentin
 Bonding Agents:An in vitro study. Al-Rafidain Dent J. 2012;12(2):228-
234.
 4.Hegde MN,Hegde P,Shetty V,Sampath P B.Assessment of antibacterial
activity of self-etching dental adhesive systems:An in vitro study .J
Conserv Dent 2008;11:150-3

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