Dentin Bonding Agents

1. DENTIN BONDING AGENTS
DR HONAP MANJIRI NAGESH
DEPARTMENT OF CONSERVATIVE DENTISTRY AND ENDODONTICS

2. CONTENTS
▶ INTRODUCTION
▶ ROLE OF ADHESIVE DENTISTRY
▶ CONCEPT OF ADHESION
ENAMELADHESION
DENTINE ADHESION
CHALLENGES IN DENTINE ADHESION
▶ ENAMEL BONDING
STEPS FOR ENAMEL BONDING
MECHANISM INVOLVED

3. ▶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

4. ▶ ROLE OF MICROLEAKAGE
▶ BIOCOMPATIBILITY
▶ ANTIBACTERIAL PROPERTY
▶ CLINICAL FACTORS IN DENTINE ADHESION
▶ NEWER CLINICAL INDICATIONS OF DENTINE
ADHESIVES
DESENSITISATION
ADHESIVEAMALGAM RESTORATIONS
INDIRECTADHESIVE RESTORATIONS
▶ FAILURES IN DENTINE BONDING
▶ SUMMARY
▶BIBLIOGRAPHY

5. 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".
(TheAmerican Society for Testing and Materials)

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

7. ▶ 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.

8. ▶ 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.

9. MECHANISM OF ADHESION:
MECHANICAL
ADSORPTION
DIFFUSION
COMBINATION

10. 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.

11. 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.

12. 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.

13. 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.

14. 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.

15. 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

16. 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

17. 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

18. ▶ 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

19. 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’sArt & Science of operative dentistry,4th edition)
▶ It is 1-10 µm thick .

20. ▶ 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.

21. ▶ 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%.

22. 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.

23. ▶ 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.

24. 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)

25. 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 ETCHADHESIVES
 TWO COMPONENT –SELF ETCHADHESIVE(SIXTH GENERATION)
o TWO STEP-TWO COMPONENT –SELF ETCHADHESIVE
o ONE STEP –TWO COMPONENT - SELF ETCHADHESIVE
 SINGLE COMPONENT-ONE STEP-SELF ETCHADHESIVE(SEVENTH
GENERATION)

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

27. ▶ BASED ON MODERN ADHESION STRATEGY:
Van Meerbek et al(2001) suggested a classification based on adhesion strategy.
TOTAL ETCH SELF ETCH
TWO STEP
THREE STEPADHESIVES
MILD
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

28. ▶ BASED ON THE TREATMENT OF SMEAR LAYER:
 Smear layer modifying
 Smear layer removal
 Smear layer dissolving

29. 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

30. TYPE OF RESIN EXPANSION
Bis-GMA Bisphenol A glycidyl methacrylate
HEMA 2-hydroxyethyl methacrylate
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

31. ▶ 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).

32. ▶ 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

33. ▶ 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

34. FIRST GENERATION DENTIN BONDING AGENT
▶ It consisted of surface active co-monomer NPG-GMA(N-phenylglycine
glycidyl methacrylate)
▶ MECHANISM OFACTION:
▶ 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)

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

36. SECOND GENERATION DENTIN BONDING
AGENT:
▶ Introduced in 1978.
▶ They were based on phosphorous esters of methacrylate derivatives.
▶ MECHANISM OF ACTION:
▶ 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.

37. ▶ 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.

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

39. 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.
▶ MECHANISM OFACTION:
▶ 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

40. ▶ 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)

41. COMPOSITION OF SOME III
GENERATION
DENTIN BONDING AGENTS
Adhesive
system
Etchant Primer Adhesive Bond
strength
Scotch Bond 2.5% maleic HEMA Bis GMA 8.8 Mpa
2 acid + 55%
HEMA
Tenure aluminium NPG-GMA. BisGMA, 15 Mpa
Oxalate
bonding
oxalate in TEGDMA
system 2.5% nitric
acid
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.

42. 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 ETCHADHESIVES
 TWO COMPONENT –SELF ETCHADHESIVE(SIXTH GENERATION)
o TWO STEP-TWO COMPONENT –SELF ETCH ADHESIVE
o ONE STEP –TWO COMPONENT - SELF ETCHADHESIVE
 SINGLE COMPONENT-ONE STEP-SELF ETCHADHESIVE(SEVENTH GENERATION)

43. 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.

44.  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.

45. ▶ 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.

46. ▶ 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.

47. 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.

48. 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.

49. 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.

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

51. ▶ 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

52. ▶ 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.

53. ▶ 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

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

55. ▶ 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 .

56. 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.

57. 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.

58. 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

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

60. ▶ 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

61. 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)
 TWO COMPONENT –SELF ETCHADHESIVE(SIXTH GENERATION)
o TWO STEP-TWO COMPONENT –SELF ETCHADHESIVE
o ONE STEP –TWO COMPONENT - SELF ETCHADHESIVE
 SINGLE COMPONENT-ONE STEP-SELF ETCHADHESIVE(SEVENTH
GENERATION)

62. 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.

63. ▶ 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 practice

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

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

66. 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.

67. ▶ 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)

68. 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)

69. ▶ 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.

70. ▶ In the sixth generation dentin bonding systems, acidic monomers like 4-
META 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.

71. ▶ 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.

72. ▶ 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).

73. 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.

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

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

76. 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.

77. ▶ 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.

78. ▶ 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.

79. 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.

82. 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

83. 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.

84. ▶ 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.

85. ▶ 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”.

86. IS FUTURABOND DC-THE EIGTH
GENERATION
BONDING AGENT?

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

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

89. 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.

90. 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.

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

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

93. Thank you