Bonding in Orthodontics

BONDING
Dr. Farisha Mohammed
1

CONTENTS
• Introduction
• History and Evolution of Bonding
• Bonding Vs Banding
• Properties
• Mechanism of Bonding
• Steps in Bonding
– Cleaning
– Etching
– Applying Primer
• Types of Primer
• Adhesive – Cements & Composites
2

• Curing Light
• Types of Bonding
• Bracket bonding -Other Non-Enamel surface
• Special Conditions
• Conclusion
• References
3

INTRODUCTION
“Bonding is mechanical locking of an adhesive to
irregularities in the enamel surface of the tooth and to mechanical
locks formed in the base of orthodontic attachment.”
Successful bonding depends on three components
•Tooth surface & its preparation
•Design of attachment base
•Bonding Material
Contemporary Orthodontic Appliance 5th ed – William R. Proffit 4

Bonding is a term conventionally used to describe the
attachment of the bracket using bonding resins to the enamel
surfaces.
Both physical and chemical forces play a role in the
process; however, the mechanical interlocking of the low
viscosity polymer bonding agent and the enamel surface is the
principal mechanism of attachment between the enamel and
resin-bonding systems.
Textbook of Orthodontics – Samir E Bishara 5

•In 1995 BUNOCORE introduced acid etching technique. He
demonstrated increased adhesion produced by acid pretreatment
of enamel. This led to dramatic changes in practice of orthodontics .
• 1965-with the advent of epoxy resin bonding NEWMAN began
to apply these findings to direct bonding of orthodontic
attachments
• In early 1970s considerable number of preliminary reports were
published on different commercially available direct & indirect
bonding system.
7

8
•A survey conducted by LEONARD GOERLICK in 1979 JCO
revealed almost 93% of orthodontists started bonding
brackets (at least in anteriors )instead of banding.

EVOLUTION OF BONDING
“An appliance which cannot be made transparent or tooth-
colored should at least be made smaller”
9

• In the mid-1960s, Dr George Newman, an
orthodontist in Orange, New Jersey, and
Professor Fujio Miura, chair of the
Department of Orthodontics at Tokyo Medical
and Dental University in Japan, pioneered the
bonding of orthodontic brackets to enamel.
10
The evolution of bonding in orthodontics ,Paul Gange - Am J Orthod
Dentofacial Orthop 2015;147:S56-63)

• In the early 1970s, Miura developed a technique for
bonding polycarbonate plastic brackets to phosphoric acid
etched enamel using a restorative filling material
developed by Masuhura et al
• The adhesive, Orthomite (Rocky Mountain Orthodontics,
Denver, Colo), consisted of methyl methacrylate and
polymethyl methacrylate with tri-n-butylborane as the
catalyst
• Miura found that the bond strength decreased with time
as a result of exposure to oral fluids.
11The evolution of bonding in orthodontics ,Paul Gange - Am J Orthod Dentofacial Orthop
2015;147:S56-63)

• Newman continued his work with epoxy resins, while
Retief et al from South Africa developed an adhesive to
bond metal brackets, based on research conducted by
Bowen on epoxy resins.
• Epoxy resins
did not experience significant polymerization shrinkage
when setting,
had the same coefficient of thermal expansion as enamel,
and were cross-linked to minimize water absorption.
2015;147:S56-63)

• Retief et al partnered with 3M Unitek (Monrovia, Calif)
to develop a mesh grid welded onto flattened stainless
steel band material with a metal bracket welded to it
• The primary drawback -the weld spots on the mesh
base prevented the adhesive from flowing between the
mesh and the foil pad properly- resulting in reduced
mechanical retention
2015;147:S56-63)

14
• In the early 1970s, 3M Unitek's Concise and Adaptic from
Johnson&Johnson (NewBrunswick, NJ) were popular
composite restorative filling materials, formulated from the
research conducted previously by Bowen.
• Both systems used a 2-paste bisphenol A glycidyl
methacrylate (BisGMa) resin with quartz as a filler and
amineperoxide as the catalyst. These systems were cross-
linked adhesives that experienced minimal polymerization
shrinkage.
The evolution of bonding in orthodontics ,Paul Gange - Am J Orthod Dentofacial Orthop
2015;147:S56-63)

• At this time, metal brackets were
welded to a perforated base
• The only complaint with
perforated base brackets was that
the adhesive covering the base
through the perforations was
affected by the oral environment
so that it often became stained
and discolored during routine
orthodontic treatment. 15
Fig 1. Perforated metal bracket base.

• In 1974, Dentsply/Caulk (Milford, Del) introduced the first
single-paste ultraviolet (UV) light curable bracket adhesive,
Nuva Tach; this system used a UV unfilled bonding resin
(Nuva Seal) on the enamel and a single UV curable paste
(Nuva Tach).
• Polymerized with light-emitting energy in the 280-nm range
• The use of these UV light cured systems was cut short when it
was discovered that they were harmful to exposed skin and
eyes, sometimes even resulting in burned soft tissues.
16
The evolution of bonding in orthodontics ,Paul Gange - Am J Orthod Dentofacial Orthop
2015;147:S56-63)

• In the early 1980s, McNamara and Howe introduced
a version of the Herbst appliance, the acrylic splint
design, that was made from 3-mm-thick splint Biocryl
(Great Lakes Orthodontic Products, Tonawanda,NY)
• Soon thereafter, the acrylic splint expander was
developed as a mixed-dentition appliance for the
treatment of maxillary constriction and Class III
malocclusion.
17

• Both appliances necessitated the bonding of splint Biocryl to the
maxilla, a procedure that required a strong, thin paste that
adhered well to plastic and resisted washout from under the
appliance. Excel was developed in 1983 by Reliance Orthodontic
Products(Itasca, Ill) specifically for bonding large acrylic
appliances.
• Excel allowed appliances to be bonded and removed successfully
without decalcification occurring during treatment.
18

19
•In 1979, Ormco (Orange, Calif)
developed and patented a
technique to braze mesh to a metal
foil pad, eliminating strength-
reducing weld spots
•This design allowed the adhesive to
penetrate between
the mesh and the foil pad, thus
increasing mechanical
retention

• In the early 1980s, visible light–cured restorative
materials were introduced in all areas of dentistry
• The catalyst for these adhesives was
camphorquinone, which cured in the visible light
range (440-480 nm) with a quartz-tungsten-
halogen light, making them safe for exposed eyes
and skin.
20

• In 1985, Suh produced Enhance for Reliance Orthodontic
Products, which made bonding to fluorosed and atypical
surfaces possible with any chemical or light-curing system.
• Enhance was applied on the etched enamel before the
unfilled resin. In addition, the monomer in Enhance (biphenyl
dimethacrylate) bonded chemically to composite and metal.
• Clinicians -the ability to bond to any metal surface without
using a metal primer or to a composite restoration without
using a plastic conditioner.
2015;147:S56-63)

• Crypsis, a color-change adhesive, was introduced in
1986.
• This 2-paste dual-cure bracket adhesive was
developed and marketed by Orec (Beaverton, Ore)
• The 2-paste material was yellow after it was mixed
but it turned tooth color when it polymerized.
• This color characteristic allowed the operator to see
the composite flash around the bracket base and
remove it before it polymerized. 22

• The color-change mechanism was a function of
the light-cure catalyst.
• In 2004, several single-paste light-cured, color
changing adhesives entered the market from
Reliance Orthodontic Products, 3M Unitek, and
Ormco.
23

• In 1995, Silverman et al developed a technique for
bonding metal brackets to wet enamel with no acid
etching using Fuji Ortho LC (GC America, Alsip, Ill), a
dual-cure glass ionomer cement.
• This 2-part system comprises a powder
(fluoroaluminosilicate glass) and a liquid (polyacrylic
acid, water, hydroxyethyl methacrylate[HEMA], and
camphorquinone-light activator).
24

• In 1996, 3M Unitek introduced a metal bracket
system with a light-cured adhesive preapplied to
the base. The operator simply etched the enamel
surface, applied an unfilled resin to the enamel,
and placed the bracket.
• The prepasting by the bracket manufacturer
eliminated the need for an assistant to place the
composite on the bracket base.
25

• In 1998, several hydrophilic primers were
introduced.
• Ortho Solo (Ormco), Assure (Reliance
Orthodontic Products), and MIP (3MUnitek) were
hydrophilic bonding resins that bonded well to
wet or dry enamel,making the bonding procedure
more forgiving.
26

• Microetching (sandblasting) became the mechanical
preparation of choice in the dental restorative field in the
early 1990s.
• Aluminum oxide, the preferred abrasive powder for intraoral
microetching, created fine surface roughness and significantly
increased the mechanical retention to artificial surfaces
27

• In 2000, self-etching primers became effective in
conditioning dentin and enamel.
• Self-etching primers such as Transbond Plus (3M
Unitek) and SEP (Reliance Orthodontic Products)
now are part of the orthodontic armamentarium
because of their lack of rinsing and drying steps,
steps that are necessary with traditional
phosphoric acid etching.
28

• In 2003, Pro Seal (Reliance Orthodontic
Products) was introduced into the
marketplace as a light-cured, fluoride-
releasing filled sealant that would remain
intact on the exposed enamel for 2 to 3 years
even under toothbrushing conditions
29

• In 2005, LED Pro Seal (Reliance Orthodontic
Products) was introduced to accommodate
the clinician using the new, cordless light-
emitting diode lights that emitted a photon
between 440 and 480 nm.
30

• In 2010, Select Defense (ClassOne
Orthodontics,Carlsbad, Calif) was introduced
as an enamel sealant hat contained selenium,
an antimicrobial.
31

32

BONDING OVER BANDING
1. Esthetically superior.
2. Faster & Simpler.
3. Less discomfort for the patient
4. Arch length is not increased by band material.
5. Allows more precise bracket placement even in
tooth with aberrant shape.
6. Improved gingival health.
7. Better access for cleaning.
33

8.Mesiodistal enamel reduction possible during treatment.
9.Interproximal areas are accessible for composite buildup.
10.Caries risk under loose bands is eliminated. Interproximal caries
can be deducted & treated.
11. No band spaces to close at end of treatment.
12. Brackets can be recycled further reducing the cost.
13.Invisible lingual brackets can be used when esthetic is
important.
14. Attachments can be bonded to fixed bridgeworks.
34

MECHANISMOF BONDING
1. Physical - based on secondary forces
– Vander Waals forces, hydrogen bonds,
dispersion forces( specially when surfaces are smooth
and polished )
2. Chemical - based on primary forces
– covalent, ionic, metallic bonds.
3. Mechanical -based on penetration of one material into
another at microscopic level (when surfaces are
rough).
35

BONDING
MECHANICAL
Formation of
resin tags
DIFFUSION
Precipitation of
substances on the tooth
surfaces to which resin
monomers can bond
mechanically (or)
chemically.
ADSORPTION
Chemical
bonding
COMBINATION
36

BONDING PROCEDURE
Cleaning
Enamel Conditioning
Sealant
Bonding
37

PRE-TREATMENT
• Cleansing
– Improves wetting
• Acid etching
– Improves adhesion micromechanical retention.
Pre-treatment is necessary as mouth is complicated
by saliva ,acquired pellicle , different organic and
inorganic components of enamel and dentin.
38

CLEANING
Removal of salivary pellicle & contaminants
Salivary pellicle -When a tooth is cleaned in situ, salivary
proteins and glycoproteins with a strong affinity for enamel very
quickly adsorb to the tooth surface and form a very thin layer
called salivary pellicle.
Material used – Pumice
Improves wetting
40

CLEANSINGWITH PUMICE
•Polishing brushes / Rubber Cup
•Low-speed
•<20,000 rpm – Micromotor
•Non-fluoride pastes for 10 sec
•Enamel – 5-14µm in depth
41

MOISTURE CONTROL
•Cotton Rolls
•Saliva ejector
• Cellulose Strip
•Absorbant
•Anti-sialogues
•Nola System
44

TYPES OF ETCHANTS
o Strong acids
o 37% phosphoric acid for 15 seconds
o Provides a strong bond
o Weak acids
o 2.5% nitric acid
o 17% maleic acid for 30-60 seconds
45

• Organic acid
– Maleic acid ,EDTA ,citric acid, tartaric acid.
• Inorganic acid
– phosphoric acid, nitric acid.
• Polymeric acid
– poly acrylic acid
46

47
Morphology of Enamel
Longitudinal section under microscope
• Enamel prisms (rods) – 5-12 million
• Diameter:4-5 µm
• Thickness : 1000 to 2000 µm (except as it tapers
toward the cervical margin) [Diedrich,1981]
• Extend from DEJ to outer surface
• Wider – Prism head
• Narrower – Prism tail

48
•Enamel is made up of a series of closely packed hexagonal 'prisms' of hydroxyapatite.
•The circular or hexagonal features on the surface of enamel shown here represent
the ends of these hydroxyapatite crystals. ('keyhole' or 'fishscale' appearance ).

TYPE 1- INTRAPRISMATIC – REMOVAL
OF PRISM CORES
Type 1 –Most common.
Preferential removal of enamel prism cores & periphery
intact.
50
HONEY COMB

TYPE 2 – INTERPRISMATIC – REMOVAL
OF PRISM PERIPHERIES
Type 2 - Reverse of type 1.
Periphery removed and cores intact.
51
COBBLE STONE

TYPE 3 – BOTH TYPE 1 & 2
Type 3 –Etching pattern less distinct.
Both types 1 & 2 present. 52

53
TYPE 4
Pitted enamel surfaces with
unfinished puzzles, maps, or
networks like
Type 3 -

54
TYPE 5
Flat, smooth surfacesType 5 -

Examples of Conditioners
 35%-37% Phosphoric acid
 10% Phosphoric acid
 Maleic acid
 EDTA
 Citric acid + 3% ferric chloride
37% phosphoric acid is a good etchant and conditioner.
A properly etched enamel surface gives a frosty
white appearance on drying.
55

57
What is the optimal etching time?
• No differences in bond strength are detected between 15 second and
60 second etching with 37% phosphoric acid; however, shorter etching
times cause less enamel damage on debonding.
• Acording to William A. Brantley decreasing etching time between 30 and 10
seconds does not affect bond strength, whereas etching for 0 or 5seconds
reduces bond strength ( less than 3 MPa ) significantly.
• Scanning electron microscopy shows that etching with 37% phosphoric acid
for at least 30 seconds produces more optical etching patterns than etching
for 15 seconds.

58
• ConcentrationofAcid?
• Etching with10% or37% phosphoric acidproducesthehighest bond strengths(28 MPa)toenamel.
No differences in bond strengths are observed when enamel is etched with phosphoric acid ranging
in concentration from 2% to 37%. One study reported that 2% phosphoric acid etchant was
adequateforbonding,whereasanotherrecommended10 –37%phosphoricacid.
• Wolfgang Carstensen (AJO 1995). Compared three acid concentration (37%, 2% and 5%) was
usedfor30 secondstobondthebrackets.Theresultsshowedthat37% phosphoric acid hada higher
bondstrength.
The amount of adhesive left on the teeth after debonding was smaller for 2% acid than 37%
and 5%, and it was concluded that 2% phosphoric acid solution is appropriate for bonding of
brackets and the reduced etching could be favorable in preventing enamel damage during the
treatmentandatthetime ofdebonding.

59
• Wasundhara(AJO) made an invitro study to detect the etch pattern and compare the shear bond
strength by using 37% and 5% phosphoric acid and it was observed that there was no significant
differencein shearbondstrength,but5%phosphoricacidproduceda minimal enamel loss.
• Whatispreferred procedure fordeciduousteeth?
• Acording to Zachrisson recommended procedure for conditioning deciduous teeth is to sand blast
with 50 μm aluminum oxide for 3 seconds to remove some outermost aprismatic enamel and then
etch for30secondswith Ultra-Etch35%phosphoricacidgel.

60
• Is prolonged etching necessary when teeth are pretreated
with fluoride?
M. Brannstrom et al(1982 AJO) suggested that extra
etching time is not necessary when teeth have been pretreated
with fluoride. When in doubt, check that the enamel looks
uniformly dull and frosty white after etch. If it does, surface
retention is adequate for bonding.
• Will incorporation of fluorides in the etching solution will
decrease the bond strength?
Fluoridated phosphoric acid solutions and gels provide
an etching effect similar to nonflouridated ones and give
adequate bond strength in direct bonding procedures.

61
• F.Garcia et al (AJO 1991) compared the enamel morphology
and shear bond strength of orthodontic bonded to enamel
etched with fluoridated or a non fluoridated phosphoric acid
gel. The result showed that overall morphologic etching effect
was similar in both groups.
• J .B Thornton et al found that addition of fluoride to the
phosphoric acid solution reduce the decalcification adjacent to
bonded brackets.

62
• How much enamel is removed by etching and how deep are the
histological alterations?
A routine etching removes 3 to 10 μm of surface enamel.
Mark Daniel et al (AJO 1980) found that a 90 second etch with
phosphoric acid resulted in mean loss of 6.9µm with no significant
difference between liquid and gel.
Deeper localized dissolutions will generally cause penetration to a
depth of about 100µm or more.
.

63
Are they reversible? Is etching is harmful?
• Although laboratory studies indicate that the enamel alterations are
largely reversible ( though not completely ) it can be stated that the
overall effect of applying etchant to healthy enamel is not
detrimental.
• This is augmented by the fact that normally enamel is 1000
to 2000 µm thick, abrasive wear of facial enamel is normal and
proceeds at a rate of up to 2 µm per year on facial surface are self
cleaning and not prone to caries.

64
On application:
•Dab- do not rub etchant on the enamel ..it may fracture the
exposed enamel.
•Do not allow etch to contact skin or gingiva.

RINSING
• After etching, the enamel surface should be throughly rinsed with a
continuous stream of water spray for 5-10 sec so that acid is completely
washed off.
DRYING
• This should be followed by proper drying which will produce frosty, white
appearance.
• Contamination of the etched and dried enamel surface by saliva, moisture
or blood can prevent proper bonding.
• If any sort of contamination occurs, repeat the procedure.
65

Contemporary Orthodontic Appliance 5th ed – William R. Proffit
67

68
GEL FORM
•Intended area is etched
DISPENSING
•Phosphoric acid is produced in a liquid or gel form and neither form demonstrated any
negative effects on bond strength.
(Brännström & Malmgren, 1982)
LIQUID FORM
• More area beyond the bracket base is etched due to displacement of the acid by
gravitational force.
•Unnecessary demineralized areas are produced in the enamel surface, which can cause
plaque and bacterial retention areas.
•Gingival structures should be carefully protected during etching with liquid form
(Øgaard & Field, 2010).

Alternative to Acid Etching
• Crystal Growth
• Laser
• Air Abrasion / Sand Blasting
69

• Also called as Crystal bonding.
• Polyacrylic acid containing sulfate ions
applied.
• Reacts with the calcium in the enamel
surface forming CaSO4 Dihydrate
(Gypsum) –chemical bond with
enamel.
• Crystal enucleation site for mechanical
bond with adhesives.
Needle-shaped crystals
Crystal growth technique (Smith & Cartz, 1973)
70

71
Advantages :
• Easier debonding, less adhesive left on tooth and less damage
to enamel.
• Minimal effect on the outer, fluoride-containing enamel
surface.
• No resin tags left behind in the enamel surface.
Disadvantages :
• Bond strength 60-80% of strength obtained with acid etching.
• 64.4% bond failure compared to 3.4% of conventional.
(Mac phee etal 1985).

AIR ABRASION/ SANDBLASTING/
MICROETCHING
Micro-etcher uses high speed 50µ Aluminium oxide
particles which are propelled against the surface by air
pressure.
72

• Mechanism of action: Localized melting and ablation in effect
etching it through micro-explosion of entrapped water in the
enamel of hydroxyapatite crystals.
LASER ETCHING
•Converts light energy to thermal
energy
•Lasers can be used :
o Neodymium-yttrium-
aluminum garnet (Nd:YAG)
o CO2
o Er:YAG lasers.
73

CONTENTS
• Introduction
• History and Evolution of Bonding
• Bonding Vs Banding
• Properties
• Mechanism of Bonding
• Steps in Bonding
– Cleaning
– Etching
– Applying Primer
• Types of Primer
• Adhesive – Cements & Composites
76

• Curing Light
• Types of Bonding
• Bracket bonding -Other Non-Enamel surface
• Special Conditions
• Conclusion
• References
77

SEALING
79
Sealer / Primer / Intermediate resin
• Low viscosity resin which is applied prior to
bonding
• After etching a thin layer of sealant may be
painted over entire enamel surface . Its best applied
with a small foam pellet or brush & it should be thin
& even.

Use of sealant led to many divergent conclusions.
1. They might be necessary to achieve proper bond
strength
2. Its necessary to improve resistance to micro leakage.
3. After sealant coating moisture control may not be
extremely important.
4. It provides enamel cover in areas of adhesive voids.
80

5. Sealant might permit easier bracket removal &
protect against enamel tear outs during debonding. (
Zachrisson BU et al 1995 JCO)
6. Study by Leonardo Foresti et al Angle 1994 showed
sealant actually increases no., & length of resin tags.
Also more fluid resin coupled with previously applied
sealant penetrates deeper into enamel & forms longer
tags.
81

APPLY RESINTO PREPARED ENAMEL SURFACES.
A Colour Atlas of Acid Etch Technique – J.J. Muray , T.G. Bennet 82

GENERATIONS OF BONDING
AGENTS
83

Buonocore (1956)
Resin containing glycerophosphoric acid dimethacrylate
Bowen
N- phenyl glycine &glycidyl methacrylate (NPG-GMA)
Bonding- chelation of bonding agent to calcium of dentine
•DRAWBACK
•Poor dentine bonding
•Enamel bonding is good.
•Poor bond strength (1 to 3 MPa ).
The first commercial system of this type – Cervident, SS White
I - GENERATION
84

85
II–GENERATION
Late 1970’s
• Incorporated halophosphorous esters of unfilled resins
• bis –GMA : bisphenol – Aglycidal methacrylate
• HEMA : hydroxyethyl methacrylate
• Bonding - through anionic bond to calcium by chlorophosphate groups.
• Weak bond strength
• Scotch Bond(3M Dental )
• Clearfil (KurarayCo. Japan)

86
• Late 1980’s, principle- partially removed or modified smear
layer
• Theprimer contains hydrophilic resin monomers which include
– 4–META :hydroxyethyl trimellitate anhydride OR
– BPDM : biphenyl dimethacrylate
• Hydrophilic group infiltrates smearlayer
• Bonding : Smear layer softening – resin cures which forms hard surface. Unfilled
resin adhesive is applied, attaching curedprimer to the composite resin.
• Drawback – Bonding to smearlayer
 Mirage bond
 Scotch bond
 Prisma Universal bond 2and 3
III-GENERATION

IV- GENERATION
87
•Total etch technique
•Complete removal of the smear
layer is achieved
•40% phosphoric acid for 15 to 20
seconds
•Bond Strength – 17-25 Mpa
All bound -2 (BISCO)
Scotch bond Multipurpose (3M)
Optibond FL (Kerr)

V -GENERATION
ONE –BOTTLE SYSTEM
•Primer and adhesives are combined into one solution
•Show high bond strength values both to the etched enamel
and dentin due to adhesive lateral branches and hybrid
layer formation.
•Total etching was done with 35 - 37% phosphoric acid for 15 to 20 secs.
•Bond Strength – 20-25 Mpa
Single bond (3M), Onestep (BISCO), Primeand Bond (Dentsply)
88

VI- GENERATION
•Etchng was not required at least at the Dentinal interface -they
contained dentin conditioning agent as one of their components
Drawbacks:
•Multiple components
•Multiple steps
89

VII- GENERATION
•All in ONE
•I - Bond
•Etching
•Priming
•Bonding
Late 1990’s & early 2000’s
90

Transbond™Plus Self Etching Prime
Squeeze liquid from black reservoir towards the
applicator
Squeeze liquid from white reservoir into purple
Churn and swirl
92

• A self etching self adhering flowable composite
technology eliminates the need for separate bonding
application step with composites for direct
restorative procedures.
• Stable nanofiller that will not settle out of dispersion.
• Highly functionlised SiO2
• Nano Particle - < 20nm
• Bond Strength – 30Mpa
• Curing time – 35 sec
• Vertise flow (Kerr), Single Bond, Optic Bond Solo
Plus, Adper Single Bond 2 adhesive, Futurabond DC,
Voco, Germany 3M 93
EIGHTH GENERATION

MOISTURE INSENSITIVE PRIMERS (MIP)
• Moisture – Resistant
An aqueous solution of methacrylate functionalised
polyalkenoic acid copolymer & hydroxyethyl –
methacrylate
• Excess interfacial water ionizes carboxylic gps forming
hydrogen bonded dimers, thus water is incorporated in
bonding mechanism
• Application of primer on wet enamel surface.
• Useful in difficult moisture condition. eg.impacted
teeth, partialy erupted teeth
• Transbond MIP (3M). 94

95
In vitro study
• Compared the bond strength of bracket
bonded with hydrophilic primer with
conventional primer
• Concluded that the bond strength obtained
with hydrophilic prime were significantly lower
than conventional primer
S.J.Little Wood et al ( BJO 2000 )

TYPES OF ADHESIVES
Cements
Composites
96

Matrix type
Resin
matrix
Salt
matrix
Salt & resin
matrix
Polymerization Initiation
Mechanism
Chemical
cure
Light
cure
Dual
cure
CLASSIFICATION OF BONDING
MATERIALS
Thermocure
Fluoride
Content
Filler
Content
Acrylic
resins
Diacrylate
resins
Glass ionomer
cements
Resin – ionomer
hybrids
Fluoride
releasing
systems
Nonfluoride
releasing
systems
Low or
unfilled
Highly
filled
97

Composite resin
• Resin matrix
– monomer (BIS-GMA, UEDMA,TEGDMA)
– Initiator (Benzyl peroxide,Campharoquinone)
– inhibitors (4 Methoxy phenol)
– pigments
• Inorganic filler
– glass
– quartz
– colloidal silica
• Coupling Agent
OCH2CHCH2O-C-C=CH2CH2=C-C-O-CH2CH-CH2O-C-
CH3 CH3
CH3
CH3OH OH
O O
Bis-GMA
CH3-C-C-O-CH2-CH2-CH2-Si-OH
CH2
O OH
OH
Bonds with filler
Silane
Bis-GMA
Bonds with resin
3D combination of atleast two chemically different materials with
a distinct interface separating the components

• Light activated resins
UV light:
– Initiator- Benzoin ethyl ether
– Activator- UV light (wavelength of 365nm)
Visible light :
– Initiator- Camphorquinone 0.25% wt
– Amine accelerator- Dimethyl-aminoethyl-methacrylate (DEAEMA 0.15%)
– Activator- visible light(420- 450nm)
• Chemically activated resins
Initiator- Benzoyl peroxide
Activator- Tertiary amine (dihydroxy ethyl p toludine)

Two phase/ Mixed adhesives- (Concise 3m)
One paste initiator & activator on the other
• Polymerization initiation
– by mixing of pastes
Start of mix Start of gel Initial set Final set
Working time Gel period
Working time- brackets are placed and positioned
Gel period- brackets must not be placed or positioned
Final set- archwires may be placed
Chemical cure adhesives

• Clinical handling
– Time consuming
• Properties
– Increased exposure of components to air induces
oxygen inhibition.
– Mixing introduces defects in the form of air
entrapment and formation of voids.

– Bonding agent on the etched enamel and
bracket backing.
– One paste under light pressure
– Efficient application
– Limited time requirements.
Activator sealant
Adhesive paste
•Enamel and bracket sides of adhesive
are more polymerized relative to middle
zones.
One phase / no mix [Rely - a – Bond( reliance),Unite (3M)]

Light cure sealant
Light cure paste
Light cure adhesives
• Polymerization initiation by exposure
to light curing source
• Extended working time (command
setting).
• Useful in situations where quick set
is required- Eg.attachment on
impacted canine after surgical
uncovering with the risk for
bleeding.
• Bond strength has been studied extensively and supports their
use. (Theodore)

– Initiation is achieved through exposure to light .
– Reaction proceeds following a chemically cured pattern.
– Combines advantages of both light & chemical cure resins.
– Prolonged clinical application process as both mixing and
photocuring are required.
– Mixing may induce air incorporation leading to porosity in the
set material.
• Ideal candidates for bonding molar tubes.
Dual cure adhesives

– Through exposure to heat
• Used for indirect orthodontic bonding and restorations.
• Properties
– Superior properties : increased polymerization rates.
– Use is limited as increased temperature is required to initiate
polymerization and the necessity for adapting an indirect
bonding set up.
Thermocure

•Setting Reaction: The hydrogen ions of the acid attack the glass
particles in the presence of water releasing calcium, strontium,
and aluminium ions. The metal ions combine with the carboxylic
group of the polyacid to form the polyacid salts matrix and the
glass surface is changed to a silica hydrogel.
GLASS IONOMER CEMENTS
•Invented -1969 reported 1971 by WILSON AND KENT
POWDER LIQUID
Poly alkenoic acid
(carboxyl containing acid)
Flouroalumino
silicate glass
106

GIC
Advantages Disadvantages
Fluoride release
Hydrogel phases
Moisture tolerance
Bond strength less
than that of composite.
•Hydrogel phase: responsible for the uptake
and release of added environmental fluoride from
topical gels, rinses & dentifrices.
107

108
•Use of GIC for direct bonding was described by White in
1986.
•Many in-vitro studies have suggested that GIC gave a
weaker bond strength with higher bond failure rates.
Miguel (AJODO 1995)
•Bond strength of 2.5-10 Mpa. (Axel 1992)

GIC’SUSED FOR BONDING TOCERAMIC
BRACKETS
CACCIAFESTA et al (1998) (european journal of orthodontics)
The lower bond strength of glass ionomer cements
might be advantageous with ceramic brackets where
high bond strengths have been associated with
enamel damage.
109

GIC COMPOSITE
RESIN MODIFIED GIC COMPOMER
PMCR’S (POLY-ACID
MODIFIED RESIN)
110

Polyacid +fluroalumino
silicate Glass particles
Monomer+photoinitiator
+light
Monomer+initiator+
catalyst
RMGIC’S
Acid –base
Polymerization (light –initiated)
Polymerization (chemical
initiator)
COMPONENTS REACTION TYPE
111

ADVANTAGES:
 Polymerization proceeds faster than acid-base
Reaction resulting in improvement of physical properties,
especially resistance.
 RMGIC-tolerates moisture similar to GIC’s.
Improved physical properties & more stable hydrogel phases
compared with GIC’s
Polymerization of resin monomers hastens initial hardening of
RMGIC,s without interfering with acid-base setting reactions (or)
any other properties.
Micromechanical interlock after polymerization
112

• Resin Matrix composite- No water
• Filler- Ion leachable aluminosilicate glass
• No acid base reaction, but light activated polymerisation.
Modified composites (Compomers or poly acid modified
composite resins)
 Study comparing GIC, RM GIC, Compomer, Light cure
& chemical cure Resin adhesive ( MILLET 1999,
ANGLE)
 No significant difference in debonding forces between
RM GIC, Compomer & Resin Adhesives except GIC.
 The amount of adhesive left in the teeth with RM GIC
was nil; half for GIC, & most of it for other adhesives.

• Properties
– Bond strength comparable to conventional
chemical cured systems.
• Efficient mode of bonding but further evidence is
required for its efficacy.
Adhesive Precoated Brackets
APC PLUS [3M]
•Color change adhesive
•Uniform coating of adhesive on each bracket
allowing for easier flash clean up.
•Moisture tolerant adhesive
•Release of a small amount of fluoride.
•Can select the bracket type.

CURING LIGHTS
Conventional curing lights
High performance halogen lights (optilux
501)
Plasma Arc Lights (PAC)
Lasers
LED’s (Light emitting diode)

Conventional Curing lights:
•Use halogen bulbs filtered to produce blue light.
•Cure adhesives under bracket in 20-30 sec.
High performance halogen curing lights:
•80 watts tungsten/quartz/halogen bulb
•Cures under metal brackets in 8 seconds and under ceramic
brackets in 5 seconds .
•Has boost mode to increase the output up to 1000 watts. hence
allows metal brackets to be cured in 5 seconds

119
Plasma arc lights:
•Generates a lot of heat and large fan is required.
•Adhesive is cured in 5 seconds under metal brackets and 3
seconds under ceramic brackets
•Plasma arc carbon (PAC) lamps have a tungsten anode and
cathode in a quartz tube filled with xenon gas.
•The gas becomes ionized and forms a plasma that consists of
negatively and positively charged particles and generates an
intense white light when an electrical current is passed .
•Plasma arc lights are contained in base units rather than in
“guns” because of the high voltage used and heat generated.
•Light intensity- 900 mW/cm2
(Zacrisson & Büyükyılmaz,2005; Büyükyılmaz & Üşümez, 2003)

Laser lights:
Emits monochromatic coherent light source
Generate lot of heat
Cumbersome

Led’s(LIGHT EMITTING DIODES)
1995 mills et al proposed solid state LEDs for
polymerization.
Solid state light emitting diode technology
•Use junctions of doped semiconductors to generate
light.
•They directly emit light in the blue region.
•LED curing of 20 and 40 seconds yielded statistically
similar results to curing of 40 seconds by conventional
halogen light sources. (Zacrisson & Büyükyılmaz,2005)

122
•Advantages :
•Have small size, are cordless.
•Quiet
•Generate minimal heat.
•Life time of > 10000 hrs
•Require no filters to produce blue light
•Lightweight, Portable and effective
•Take little power to operate.
e.g.Ledmax-4

123
• All new light sources cure resins faster than conventional halogen
lights.
•Fast halogen sources are more brand specific but generate low heat
and are less expensive than plasma lights and LEDs.
• Plasma arc lights offer the shortest curing times but are expensive
and generate heat.
•Light-emitting diodes have small size, are cordless, are quiet, generate
minimal heat, and perform favorably compared with conventional and
fast halogen sources.
•Use protective eye glasses that have filtration effects.

TYPES OF
BONDING
DIRECT
INDIRECT
125

DIRECT BONDING
• Easier, Faster
• Less expensive
• Drawbacks
– proper positioning is crucial.
– Has to be done rapidly and accurately.
126

PLACING BRACKET ON TOOTH
A Colour Atlas of Acid Etch Technique – J.J. Muray , T.G. Bennet127

PROBE USEDTO CHECK THE BRACKET POSITION TO
THELONG AXIS OF TOOTH

BRACKETS IN POSITION

INDIRECT BONDING
• First described by Silverman & Cohen in 1972.
• Placing brackets in a model
• Use template or tray to transfer
• Common agent – “No-mix” chemically activated materials
• More useful in Lingual Orthodontics
• Types
– Clear Tray
– PVS Transfer Tray
– Memosil Tray
– Single Unit Transfer Tray
130

CLEARTRAY
Clear Precision Thermoplastic
Clear Tray
131

132
Clear Transfer Trays and Adhesives
• Clear vinyl trays made on a pressure-forming
machine such as the Biostar from Great Lakes
Orthodontics have largely replaced the original
silicone tray materials.
• Advantage
– Provide a clear field of vision
– Can be easily sectioned to facilitate clinical delivery
– Makes possible the use of light cured materials with
light cure adhesive.

WINDOW TRAY
• DAS’s Incisal and
Occlusal Window Tray
• PVS – Heavy / Medium
Body
136

138
Advantages of indirect bonding
• Clinical
• Technical
• Time in motion combined with ergonomics
and efficiencies

139
• Clinical
– Improved patient comfort
– No separators or band spcaes
– Better environment for placing ceramic brackets on
mandibular teeth
– Placement of brackets in the posterior , with level slots
and a passive archwire.
– Easier to build in overcorrections
– Better in/out control
– Improved vertical control

140
• Technical
– Enhanced TMJ health
– Improved periodontal health & better hygiene
– Increase post treatment stability
• Ergonomics & efficiencies
– Optimal use of time and better staff utilization
– Fewer appliance placement appointments and
simplified and shortened debonding
– Healthier ergonomically

141
Disadvantages
• Technique sensitive
• Improper seating of indirect tray may require
complete redoing of the procedure.
• Amount of composite flash involves extra
chair time to remove.
• Posterior attachments likely to fail
• Additional set of impressions required
• Excessive laboratory time is required for
construction of the indirect setup
• Lab costs.

BONDING ON OTHER NON-ENAMEL
SURFACE
142

CERAMIC VARIETIES
GOLD
AMALGAM
VENEERS
143

DORON HARARI et al (AJO) 2003
PORCELAIN-CERAMIC BRACKETS
Preparing the porcelain surface
Mechanical retention of adhesive to bracket bases
9.6% HF gels
•2-4 minutes are used for etching porcelain surfaces
144

BONDINGTO CERAMIC RESTORATIONS
Fine diamond bur
Sandblasting
Micro-etching with alumino silicates
5%HCL
Silica coating
Surface conditioning methods
145

Buyukyilmaz T AND Zachrisson (1998)
ANGLE ORTHODONTICS
Bonding to gold- intra oral sandblasting is superior to
roughening with diamond bur
Tin plating improves bond strengths but only
marginally . This procedure is not recommended by
the FDA and hence not recommended for orthodontic
purposes.
BONDING TO GOLD
146

BONDING TO AMALGAM
Intra-oral sandblasting for 2-4 seconds at a
distance of 10mm.
Use a META intermediate resin with a short
curing time such as reliance metal primer.
147

BONDINGTO VENEERS
Kao and johston(1991)journal of prosthetic
dentistry.
•Reported fracture incidence on debonding
orthodontic brackets from porcelain veneers
Lee –knight et al (1991)AJO
•IT may be worth using a ceramic reinforced resin
bracket , such as ormco spirit or GAC Elan , on
veneers as these brackets are extremely easy to
debond.
148

ETCHING INFLUORIDATED TEETH
Fluoride ion
Hydroxy–apatite crystal
Resistant to acid-dissolution
Caries prevention
Hence fluoridated teeth requires longer etching time.
150

1.Bonded brackets have weaker attachments than cemented band.
2.If excess adhesive extends beyond bracket base increases risk of plaque
accumulation
3. Protection against interproximal caries of well contoured cemented brackets
is absent.
4.Bonding generally not indicated when lingual auxillaries or headgear required.
5.Rebonding loose brackets require more preparation than rebanding loose
bands.
6. Debonding- more time consuming due to more difficult removal of adhesives.
7. Evidence based decalcification & white spot lesion occurs more following
bonding than banding.
DRAWBACKS OF BONDING
151

CONCLUSION
• Bonding of brackets has changed the practice of
orthodontics and has become a routine clinical
procedure in a remarkably short time.
• Modifications of technical devices, sealants and
adhesives, attachments, and procedures are
continuing.

• In the past, the best clinical results were achieved by
orthodontists who had the best wire bending skills.
• However, the best results in the future will be achieved by
those orthodontists who are best at accurate bracket
positioning.
• Most of the problems associated with bonding techniques
have faded away.

REFERENCES
• Graber, Vanarsdal, Vig
• OP Kharbanda
• Contemporary Orthodontic Appliance 5th ed – William
R. Proffit
• Textbook of Orthodontics – Samir E Bishara
• A Colour Atlas of Acid Etch Technique – J.J. Muray ,
T.G. Bennet
• Textbook Of Operative Dentistry, Vimal Sikri
• Phillip’s Science Of Dental Materials
• The evolution of bonding in orthodontics ,Paul Gange
- Am J Orthod Dentofacial Orthop 2015;147:S56-63)
154

• Crystal growth on outer enamel surface - AJO-
DO 1986; 89:183 - 193 , Maijer and Smith
155

Bonding in Orthodontics

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Bonding in Orthodontics

Similar to Bonding in Orthodontics (20)

Recently uploaded

Recently uploaded (20)

Bonding in Orthodontics