Bonding

BONDING
www.indiandentalacademy.com

TERMINOLOGIES
 ADHESION :
Attraction between unlike molecules
 COHESION :
Attraction between like molecules
 MECHANICAL BONDING :
Strong attachment of 2 substances
accomplished mechanically rather than by
molecular attraction

 CONTACT ANGLE:
 Angle between the wetting medium and the
tooth surface
 AIR POCKETS:
- Created during the spreading of adhesive
- Cause bond failure
 TENSILE BOND STRENGTH
 SHEAR BOND STRENGTH

Nature of enamel
 Highly mineralised tissue
 Hardest tissue in human body
 Clinically visible
 No regenerative capacity

Morphology
 Enamel prisms
 Extend from DEJ to
outer surface at
varying angles
 Prismless enamel

Longitudinal section under
microscope
 Wider prisms
 Narrower Interprismatic
substance

Cross section
 Keyhole / fish like pattern
 Head 5 microns
 Head - incisal region
 Tail - cervical region

 Prisms contain
hydroxyapatite crystals
 Run parallel to long
axis of prism and
become perpendicular
as they approach tail

Acquired pellicle
 Precipitation of salivary proteins
 Forms almost immediately
 Removed by pumicing

Factors affecting enamel
solubility
 Pre – eruptive factors
 Post – eruptive factors

Pre – eruptive factors
 Affect chemical and histological
characteristics of enamel prior to
emergence in oral cavity
1. hypoplasia
2. hypocalcification
3. fluorosis

Post eruptive factors
 Affect the enamel solubility after eruption
1. topically applied fluorides
2. organic pellicle
3. plaque

Factors affecting bonding to
ideally etched surface
 Patient operator
saliva
Contact
with lip and
tongue
Oil / water via
spray
Rubbing /
touching etched
surfacewww.indiandentalacademy.com

Properly bonded
bracket

Over extended bonding medium
onto unetched enamel

Interfaces

HISTORY

BANDING M.E MAGILL - 1871
Negative factors :
 Time and skill
 Impacted teeth
 Decalcification /discoloration
 Gingival irritation
 Unaesthetic
 Placement of separators is painful
 Closure of band spaces

The goal was to have brackets tubes and
other attachments directly cemented on the
tooth surface to eliminate problems
encountered with metal bands.

MMA - Ist
material
Methyl Methacrylate
Catalyst - BPO
Difficulty in adhesion
 Polymerization shrinkage
 Pulpal irritation

Buonocore - 1955
 Etched enamel with 85% phosphoric acid
to increase adhesive strength
 However adhesive strength could not be
maintained because of
1. Occlusal force
2. Wide range of oral thermal change
3. Wet environment

G.V.Newman - 1965
 Feasibility of using Plastic brackets with
Epoxy resins
 Start of Direct bonding procedure

In 1969 – I st
commercially available Ortho
adhesive was OIS Adhesive system
In 1970 - Bracket Bond ( GAC )
BPO – Amine catalyst system
Weak Adhesion

In 1971 Fujio Miura et al
Orthomite ( MMA- TBB resin )
( Tri – N – Butyl Borane )
Resulted in increased adhesive strength

MMA
 Powder and Liquid
 No filler
 Chemical adhesion with plastic brackets

MMA adhesive
MERITS
 Plastic brackets
 Good storage stability
 Good penetration into enamel surface
 Less damage during debonding

MMA adhesive
DEMERITS
 Fluctuating property between powder
liquid depending on operator technique

Plastic Metal
Plastic- Enamel adhesive bond interface
Metal- Adhesive bracket interface
Metal – Mesh , perforated pad , foil mesh
MMA - BISGMA

Drawbacks of BISGMA
1. Plastic brackets could not be used .
To overcome this the plastic bracket base
had to be partially dissolved
- PRIMER added

Drawbacks of BISGMA
 Poor penetration due to increased viscosity
 MMA + BISGMA sealant
 This meant an additional step
DILUTED

Drawbacks of BISGMA
 Active life was less than powder liquid
system
 Tooth surface damaged during debonding
with BISGMA [ filler - hardness]

Orthomite
 Adhesive
 Powder [ PMMA]
 Liquid [MMA]
 Catalyst [ TBB]
 Coupling agent [ SILANE]
Added to increase penetration into enamel crevices

 Orthomite II No silane
 Orthomite superbond 4 META
4 methacryloxy ethyl
trimellitate anhydride
could bond to metal [ NI-Cr] ,[ Co – C r]

4 META
 Plastic + metal
 PRE PRIMED brackets
 Base was primed with adhesive
 Bracket base covered with PMMA powder
 Base dipped in monomer and pressed onto
etched surface.

Bonding medium
ideal characteristics
 Non toxicity
 Adequate working and setting times
 Moderate viscosity
 Sufficient tensile and compressive strength
 Ability to wet etched surface
 Resist decomposition in the oral
environment

Mechanism of polymerization
 Chemically activated - 2 paste system
BPO – tertiary amine
 Light activated - single paste system
consists of photo initiator +amine
Exposure of light of correct wavelength
produces an excited state of photo initiator
which interacts with the amine.

Self cure Vs light cure
 Self cure
 Polymerization starts immediately
 Cannot manipulate setting time
 Air bubbles during mixing – reduce bond
strength

Self cure Vs light cure
 Light cure
 Compared to UV ,visible light deeper
curing
 Long working time
 Excess material can be removed before
polymerization

 Resin 2 types
 Acrylic resin MMA [plastic brackets]
 Diacrylate resins BISGMA[metal ]
 Filled / unfilled
 Quartz ,silica
 Particle size 3-20 microns impart abrasion
resistance
 Particle size-0.2 – 0.3 microns smooth
surface less abrasion resistance

No mix adhesive
 Sets when one paste under light pressure is
brought together with a primer fluid on the
etched enamel or another paste on the tooth
to be bonded
 One adhesive component applied to
bracket base and other on tooth surface
 As soon as bracket is positioned it is
pressed firmly into place
 Curing occurs – 30-60 secs

No mix adhesive
 ADVANTAGES
 Procedure simplified
DISADVANTAGES
 Little long term information available
on bond strength of paste – paste
system
 Liquid activators – allergic reactions

Pre coated brackets
 Plastic / metal / ceramic
 Chemical /light cured
 ADVANTAGES
1. Consistent quality of adhesive
2. Reduced flash
3. reduced waste
4. Adequate bond strength
5. Improved cross infection control

Evaluation of antimicrobial properties of
orthodontic composite resin combined with
benzalkonium chloride
Othman et al,AJO Sep2002
 The antimicrobial agent benzalkonium
chloride was added to a chemically cured
composite resin and the anti microbial
benefits and bond strength of the modified
composite were evaluated.

 No significant difference between the
tensile bond strength between modified
composite and the original product
.
 The incorporated BAC added to anti
microbial properties of original composite
without altering it’s mechanical properties

Advantages of bonding
 Esthetics
 Faster +simpler
 Less patient discomfort
 Arch length not increased
 Less gingival irritation
 Precise placement [aberrant tooth forms
banding is difficult.]

Advantages of bonding
 Interproximal enamel reduction and
composite build up possible
 Bond artificial tooth surface
 Caries risk eliminated
 No band space closure
 Lingual brackets

Disadvantages of bonding
 Weaker than bands
 Better access for cleaning does not
guarantee better oral hygiene
 No protection against interproximal caries
 Rebonding > Recementing
Adhesive > Cement

BONDING PROCEDURE

Bonding procedure
 Cleaning
 Enamel conditioning
 Sealing
 bonding

Cleaning
 Remove organic
pellicle
 Pumicing
 Using rubber
cups/polishing brush

Cleaning
 Pumice prophylaxis does not appear to
affect bond strength
 REISNAR ET AL
Buccal surfaces lightly abraded with TC bur
at slow speed 25000 rpm > Pumicing for
10 sec

Enamel conditioning
 Acid etching
 Other alternatives to acid etching
1. Crystal growth
2. Sand blasting/air abrasion
3. Laser etching

ACID ETCHING

ACID ETCHING
 1955 BUONOCORE - 85%
phosphoric acid
 37% phosphoric acid – 15 to 60 sec
 15 sec – for young permanent teeth
 30 – 60 sec – adult teeth
 Longer periods - less retension due to loss
of enamel structure

Acid etching
 Etchant should not be rubbed onto
tooth surface
 Rinsed with water spray
 Dried with moisture and oil free
source
White frosty appearance

Alternative acids for etching
traditionally 30 – 40 %
Phosphoric acid
- 10 % Phosphoric acid
- 10 % Maleic acid
- 2.5 % Nitric acid
Etch enamel as well but have significant
lower bond strength

Rationale of etching
Gwinnett,Matsui & Buonocore
 Primary mechanism of attachment of resin
Resin tags to etched surface
MICROMECHANICAL BOND
Acid etch removes 10 microns of enamel
Creates porous surface
Increases wettabilitywww.indiandentalacademy.com

Patterns of etching
Gwinnett & Silverstone
Type 1
- Selective removal of enamel prism cores
- Peripheries intact

Type 2
Reverse process
- Peripheries removed
- Cores intact

Type 3
- Less distinct
- Combination of 1 & 2
- Unrelated to Prism morphology

Conc of Etchant
 50 % phophoric acid - 60 sec
Monocalcium Phosphate Monohydrate
 27 % & less
Dicalcium Phosphate Dihydrate
 30-40 % Most retentive surface(Silverstone)

Etching Time
60 sec 30 – 40 % Phosphoric acid
Shorter etching time Reduced tensile
bond
strength
SEM studies Tensile bond strength,
Microleakage , Surface roughness
15 sec = 60 sec

 fluorosis - no extra time needed
 Fluoridated Soln/gel = non fluoridated
 Acquired / developmental
demineralization
1. Avoid etching/ keep time minimal
2. apply sealant
3. Direct bonding

Bond strength with various etching times
WEI NAN WANG ETAL AJO 1991
 Compared the tensile bond strength at
various etching times15,30, 60, 90,120 secs
 37 % phosphoric acid
 TBS was not statistically different for
15,30,60,90
 TBS decreased – 120 secs
 Debonding – fewer enamel fragments with
shorter etching times

 Compared quality and quantity of enamel etch
produced by 37 % phosphoric acid and 2.5%
nitric acid for 15 , 30 ,& 60 secs
Concluded
 37 % phosphoric acid - better etch for all 3
applications
 15 < 30 & 60
 30 = 60
 Supported use of 37% - 30 secs to get optimum
bond strength
ALASTAIR GARDNER , ROSS HOBSON AJO 2001
Acid etching

The continuous brush acid technique
BAHARAV ,LANGSAM J PROSTH DENT 1987
 Aim was to determine whether mechanical
agitation of etchant would enhance
decalcification of enamel
 Non carious pre molars
1. Mesial half – 35% P04 acid[30 secs] left
undisturbed
2. Distal half – 35% po4 acid [30 secs]
continuously painted

The continuous brush acid technique
 Results
 Continuous brushing of etchant - more
efficient dissolution of enamel
 Reduction of size of remaining crystals
 Hence increasing the potential space
between them for retension

Acid etching
Iatrogenic factors
 Loss of enamel
 Retention of resin tags discoloration
 Leakage at the bracket interface - staining
 Enamel loss – debonding
 Surface roughness – debonding plaque
retention
 Softer enamel – prone decalcification

Alternatives to acid etching
 CRYSTAL GROWTH
 SAND BLASTING/ AIR ABRASION
 LASER ETCHING

Crystal growth
SMITH
 Polyacrylic acid – chemical bonding
 Purified polyacrylic acid- slight etching
 Polyacrylic acid + sulfate ion – crystalline
deposit
 CALCIUM SULPHATE DIHYDRATE
 Depends on concentration of sulfate ions

Crystal growth
MAIJER AND SMITH
 Crystalline interface produced tensile bond
strength equivalent to conventional acid
etched surface
 Debonding fracture at crystal - resin
interface
 Other soln – sulphuric acid anion[more
reliable and uniform growth]

Crystal growth
 Calcium sulfate crystals must enucleate
from bound calcium
 To achieve this some etching is required
 Enamel solubility ~ crystal enucleation
 Mechanical attachment is created around
the crystalline interface and superficially
etched enamel
MECHANISM OF RETENSION

Crystal growth
 ARTUN AND BERGLAND
 Sulphuric acid - crystals not as long and
needle like as with polyacrylic acid but
were rounder and flatter
 Hence debonding was easier

Advantages of crystal growth
 Debonding easier and quicker
 Little damage to enamel
 Minimal effect on outer fluoride containing
enamel
 No resin tags left behind
 Possibility of incorporating fluoride in
crystal interface – anticariogenic action

Crystal growth - procedure
 One drop of viscous liquid placed on tooth
surface
 Left undisturbed for 30 secs
 Brush / swab should not be agitated as in
etching as it may affect crystal/enamel
interface
 Rinsed for 20 secs

Crystal growth - procedure
 Forceful water spray to be avoided as it
will break crystals
 Look out for a dull whitish deposit
 Bracket bonded in usual way

Sand blasting / air abrasion
 Makes use of high speed stream of
aluminium oxide particles [50/90
microns]propelled by air pressure
 Produces rough surface
 Used for cavity preparation
 Preparation of enamel /dentin

Sand blasting
 Could contribute to better bond strength
with less enamel loss
 Factors affecting bond strength
1. Particle size
2. Air pressure
3. Exposure time
4. Microstructure of enamel surface

Sand blasting
 Compared bond strength and enamel loss
between sand blasting and conventional
acid etching at varying exposure times and
air pressure
 Bond strength
Sand blasting < acid etching
 Enamel loss
Sand blasting < acid etching
WENDALA VAN WAVERAN ALBERT FEILZER
AJO 2000

Laser etching
 LASER
 Light amplification by stimulated emission of
radiation
 3 elements
 Lasing medium [ solid/liquid/gas]
 Energy source[xenon flash lamp/electrical
discharge]
 Optical resonator
1. Coherence
2. Collimation
3. Monochromaticity

Laser etching
 When laser strikes an object it may be
 Reflected
 Transmitted
 Scattered
 Absorbed
 Combination of above

Laser etching
 In order to have an effect on tissue light
must be absorbed by some elements so that
the energy can be converted into other
forms
 Production of heat undesirable effects

Classification
 Mode of excitation ( Continuous or
Pulsed)
 Wavelength
1. UV range(Krypton Flouride, Argon
Flouride)
2. Visible Light ( Helium , Neon )
3. Infra Red range ( carbon dioxide, Nd:Yag)

Laser etching with Nd : Yag
 Studied the surface effects of dentin following
laser etching with Nd:Yag and evaluated the
shear bond strength of composite between treated
and untreated laser etched dentin
 Surface roughness
laser etched > unlased dentin
 Bond strength
Laser treated >unlased dentin
M.A WILSON ET AL

Laser etching
 Shear bond strength of composite to laser
pre treated dentin increased by 300 %
 localised melting + recrystallization
 Fungiform projections
 The composite adapted to undercuts
&space between the dentin projections
LYDON COOPER ET AL

Laser etching

Pulsed krypton fluoride excimer
laser Dr Francis M
 Compared surface morphology, bond
strength,and ARI between acid etching and
3 different energy densities of pulsed
krypton fluoride laser
 440.460,480 MJ/cm2
 Concluded :
 TBS 460.> 480 >A E >440

 SBS 480 > A E > 460 > 440
 SEM regular etch pattern similar to acid
etch seen with 460 & 480 MJ/cm2

SEALING
Sealer / Primer / Intermediate resin
 Low viscosity resin which is applied
prior to bonding .
1. Necessary to achieve proper bond strength
2. Improve resistance to microleakage
3. Both reasons
4. Not needed at all

Chemically cured
Sealant
Light cured
Ceen & Gwinnett
Found
Light cured sealant Chemically cured
 Protect enamel Polymerize poorly
adjacent to bracket Have low resistance
from discoloration to abrasion

Evaluation of sealant in
orthodontic bonding
Wei Nanwang etal AJO 1991
 Evaluated the Tensile bond strength with and
without use of sealant
 They found no statistically significant
difference in the bond strength of the two
evaluated groups

However the use of sealant
 May offer extra protection to enamel
during debonding
 As chances of enamel surface detachment
with out use sealant was greater.

Self Etch Primer
Unique characteristic of some bonding
system is that they combine the
Etchant + Primer into single product
 Saves time
 Cost efficient

Procedure For Self Etch
 Teeth are pumiced
 Self etch primer gently swirled on to each
enamel surface for 2 to 5 secs
 As pH rises , etchant is converted to primer
 Primer is thinned with burst of air
 No rinsing with water
 Bracket then bonded in usual way.

Effect of self etch primer on
shear bond strength of
orthodontic brackets
Samir Bishara & Leigh Von Wald
AJO 2001
•Their study concluded that use of self
etch primer resulted in low but clinically
acceptable shear bond strength.
•Comparison of ARI scores – More
residual adhesive remained with self etch
primer.

Bonding of stainless steel brackets to
enamel with new self etch primer
Ryan Arnold et al sep 2002
 Bond strength of stainless steel brackets
using Transbond self etch primer
Four groups
A- Conventional etchant with separate primer
B- Self etch –15 sec Before
C- Self etch - 2 min bonding
D-Self etch - 10 minwww.indiandentalacademy.com

Conclusion –
 No significant difference in bond strength
between the two groups.
 10 min delay in bonding after application
of self etch primer might not be deleterious
for adhesion

Hydrophilic Primer ( MIP )
 Bond failure – Moisture contamination
 When etched enamel is wet most porosities
get plugged – Penetration of resin impaired
 Second molars – Access difficult
 Hydrophilic primer (HEMA & Maleic acid)
dissolved in acetone – 3M Unitek
( Transbond MIP )

Hydrophilic Primer
S.J.Little Wood et al ( BJO 2000 )
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

Pre primed brackets
 Stainless steel +plastic
 MERITS
 Simplification of bonding procedure
 Minimal wastage
 Less chance of contamination
 No air pockets
 Accuracy and consistency

Bonding Procedure
Four steps
1. Transfer
2. Positioning
3. Fitting
4. Removal

Transfer
 Adhesive put on
bracket base
 Bracket placed on
the tooth closed to
the correct position

Positioning
 Proper vertical
and horizontal
positioning
( eg Using
placement
scaler with
parallel edges)

fitting
 Bracket firmly
pushed towards
the tooth
surface with one
point contact

Removal of excess
 Gingival irritation
 Plaque build up
 Better esthetics
 Prevents staining
and discoloration

Curing lights
 Tungsten quartz halogen light
 Argon laser
 Xenon plasma arc light
 light emitting diode curing
units[LED]
 Pulsed xenon plasma arc light

Tungsten quartz halogen curing
light
when electric energy is passed
Halogen bulb
Tungsten filament is heated
HEAT
LIGHT
Selective filters – blue light [ 400-500
microns] www.indiandentalacademy.com

Tungsten quartz halogen curing
light
 40 seconds per bracket
 15 minutes – both arches
Disadvantages
 Curing time consuming
 Light output < 1% of consumed electricity
 Lifetime – 100hrs
 High heat - degrades components of bulb

Argon laser
 Introduced in the late 80’s &early 90’s
 Promised to reduce the curing time
dramatically
 480 microns wavelength
 Curing time
 3 secs – per bracket
 1 min – both arches

Argon laser
 KELSEY ,POWELL
To equal bond strength of 40 sec exposure by
conventional curing light argon laser must
cure for 10 seconds
Disadvantages
 Laser unit large
 expensive

Xenon plasma arch light
 Introduced in the late 1990’s
 Short exposure time at lower cost
 Curing time
3 – 5 secs per bracket

Comparison of efficiency of xenon
plasma light and conventional curing
light Sheldon Newman et al AJO 2001
 Exposure time
40 secs - conventional curing light
3 , 6 , & 9 secs – xenon plasma light
 Bond strength
xenon light > with longer exposure time
 To equal bond strength of conventional curing
light the exposure time with xenon had to be 6 –9
seconds

Light emitting diode curing units
Mills –1995
 Instead of hot filament – Halogen bulb.
 LED – junction of doped semi conductors.

Light emitting diode curing units
Advantages;
 Lifetime 10, 000 hrs
 Requires no filters
 Resist shock and vibration
 Little power to operate
 Newer –GALLIUM NITRIDE ( LED )
400-500microns

LED
 Optimum curing time ?
 Replace halogen bulbs ?
Mills et al ( BJO 1997 )
 Compared light source containing LED to
Halogen units
 Concluded – LED curing units cured
composites to significantly greater depths
when tested at 40 & 60 sec

Polymerization of resin cement
with LED curing unit
William Dunn & Louis Taloumis
AJO sep 2002
 Compared the shear bond strength of
orthodontic brackets bonded to teeth with
conventional halogen light and LED curing
units .
 Concluded- LED curing units bonded
brackets to enamel as well as Halogen
based curing lights

Pulsed Xenon Plasma Arc Light
Polymerization shrinkage
Internal stresses
Fracture of composite at tooth adhesive
interface
Microleakage / Caries

Non Pulsed Xenon Plasma Arc
Light
Non Pulsed Plasma Arc Light Light
Rapid curing
Polymerization shrinkage

Polymerization shrinkage – Over come
-Curing composite in layers
-Pulsed curing light
Pulsed curing light- unit light is a series of
pulse to polymerize the adhesive
Pulsed Xenon Plasma Arc Light

Retrofitting curing light
 Most curing lights designed for restorative
dentistry
 Probes 10-11 mm
 Flooded over larger area
NEW POWER SLOT
 Tapered rectangular tip
 4 x 7 mm
 Closer to enamel – bracket interface
 Shorter curing times

Bonding to artificial teeth
and restorations

Bonding to porcelain
 Conventional acid etch ineffective
 WOOD ET AL –[1986] showed
1. Roughening porcelain surface
2. Adding a porcelain primer
3. Using highly filled resin
Increased
bond
strength

 WOOD ET AL
 Showed that
 Bond strength to porcelain > or = bonding
to acid etched enamel
of natural teeth
 bond strength was high enough to damage
porcelain surface - debonding

 Commonly used etchant – 9.8 % HF
acid gel 2-3 secs
 Microporosites –mechanical retension
 Frosty appearance

 Surface preparation for orthodontic
bonding to porcelain
ZACHRISSON et al AJO 1996
HF acid gel = sand blasting + silane
 Some authors feel
Sand blasting + silane - high failure rates

Bonding to porcelain - procedure
 Isolate
 Deglaze area by sand blasting 50 microns –
3 secs
 Etch 9.6%HF gel - 2 mins
 Rinse
 bond with BISGMA resin
 Use of silane optional

Bonding to amalgam
 Improved bonding technique
 Modification of metal surface
[sand blasting,diamond bur roughening]
 Use of intermediate resin
 Use adhesive resin that bond chemically
to metal [4 META , 10 MDP BISGMA]

Bonding to amalgam - procedure
 Sand blast with 50 microns al oxide for 3
secs
 Etch with 37% phosphoric acid 15 – 30
secs
 Apply sealant and bond with adhesive resin
 See that bonded attach is out of occlusion
with antagonist

summary
 E+nx P+ B
 E +nxPB
Combined the primer and the bonding agent
into one soln
Needed good moisture control for good
results
 EP +B self etch primer
Gentler etching , elimination of water rinsing,
reduction in post operative sensitivity

summary
 n x EPB Prompt L pop
Etchant primer and adhesive sealed in lollipop
shaped aluminium foil packet
Used for direct application on all composites
 ONE UP BOND
First EPB to contain color change
polymerisation indicators.
when polymerized completely it shifts
from pink to tooth color

Self Etch Primer
 Prompt L Pop
 Transbond self etch primer
Liquid begins to etch as soon as it is applied

Etchant Primer
When two hydroxide
ions are converted
hydrogen ions are
realsed

Crystal growth
JOHN ARTUN , S. BERGLAND AJO 1984
 Soln A – dil sulphuric acid+sodium
sulphate
 Soln B – 10% po4 acid +dil sulphuric acid
 Failure rates recorded – 6 months
 A > B > ACID ETCH

Indirect bonding

Indirect bonding
 SILVERMAN AND COHEN – 1972
 MMA and UV light activated unfilled
BISGMA
 MMA was applied to the plastic bracket
base on the patient’s model
 BISGMA –intermediary adhesive between
the patients etched enamel & pre set
adhesive on the bracket base

Indirect bonding
 Updated technique – 1974 by same authors
 Used perforated metal bracket bases and
only one adhesive- BISGMA[ UV light
activated]
 Increased operator working time as
polymerization did not occur

INDIRECT BONDING
ADVANTAGES
 Accurate bracket placement
 Decreasing the chair side time
 Avoiding band fitting on the posterior teeth
 Eliminating the need for separators
 Improved ability to bond the posteriors
 Improved patient comfort and hygiene

INDIRECT BONDING
Disadvantages
 Technique sensitive
 Additional set of impressions need to be
taken
 Posterior attachments more likely to fail if
the patient chews on hard food

Indirect bonding techniques
 Thomas technique
 Silicon transfer tray
 Double sealant technique
 Moin & Dogon technique
 Indirect method – Anoop Sondhi
 Indirect bonding for light cured composites

THOMAS TECHNIQUE 1979
 Filled BISGMA resin placed into the
bracket bases
 Attached to the stone model
 Before setting all excess material is
removed from the cast around the brackets
 Transfer tray made of flexible material
 Tray + brackets removed from the cast as
single unit

THOMAS TECHNIQUE
 Teeth of one arch isolated +etched
 Liquid unfilled resin formed the interface
between etched enamel and filled resin
 Liquid catalyst – tooth
 Base resin – brackets
 Unfilled resin not pre mixed – working
time increased
 tray seated held till polymerization is
complete

Indirect bonding with silicone
transfer trays
 Pour the impression in stone
 mark the long axis and height on each
tooth
 Apply water soluble adhesive on each
bracket
 Position the bracket over the teeth on the
cast

 Mix putty material press onto the cemented
brackets
 Tray is formed of sufficient thickness
 Model is immersed in hot water
 Mark the midline
 Patient is prepared for direct application
 Adhesive is placed on the base of brackets
 Tray is seated and held for 3 minutes
 Tray is peeled off excess adhesive on tooth
is removed

Double sealant technique
 Adhesive paste rather than temporary
adhesives are used to bond the brackets
onto the cast
 Base + catalyst mixed placed on the
bracket bases
 Brackets placed on the tooth
 Tray is then formed placed in water

 Embedded bracket bases are lightly abraded
with with a mounted stone
 Teeth are etched
 Bracket bases are painted with[ partB]catalyst
resin
 Teeth are painted with universal sealant
[partA]
 Tray is seated held for 3 min
 Adv – clean up simple due to less
flash[unfilled resin only]

Indirect bonding
Moin & Dogon technique AJO 1977
 Pour impression in
stone
 A drop of sticky wax
is placed on teeth
surfaces of cast
 Brackets are warmed
over flame and set on
the cast

Indirect bonding - Moin & Dogon technique
 Impression made with
polyether material
 Tray separated from cast
but brackets remain in
situ
 Bracket is removed from
the cast &warmed to
remove residual wax
 They are placed into the
impression

 Teeth are pumiced,etched & isolated
 Enamel surface is sealed with mixture of
universal & catalyst sealant
 bracket base is covered with the adhesive
 tray is seated

 Use of sticky wax-corrections can easily
&readily be made until optimal bracket
alignment is obtained
 Previously used
 Adhesive tape - bracket displacement
 Bonding resin – cleaning of bracket base
prior to bonding difficult and time
consuming

Indirect bonding – ANOOP SONDHI
AJO 1999
 NEW INDIRECT BONDING MATERIAL
 3 M UNITEK / SONDHI RAPID SET
 Unique features
 Increased viscosity - silica fillers[5%]
 Quick set time – 30 secs
 Decreases the time needed for holding the
bonding tray
 Completely cured 2 min allowing rapid removal
of the tray

 Alginate impressions
made
 working models poured
in stone

 APC brackets used
and positioned over
the teeth excess
adhesive removed

 Bracket positions
checked
 Models are placed
in the TRIAD
curing unit 10
minutes

 Block the
undercuts
 Construct tray with
bioplast material
[1mm] thick
overlayered with
bioacryl

 Excess tray
material is
trimmed off with
scalpel
 Trays placed in the
TRIAD unit to
ensure that
uncured resin is
cured

 Prepare patient
 Pumice , Etch &
isolate
 Tray can be sectioned
if there is severe
crowding

 Small amounts of
resin A and B are
poured into the wells
 Resin A – tooth
surface
 Resin B – resin pads
in the tray

 Seat the tray over the
teeth
 Hold with uniform
pressure for 30
seconds
 Leave the tray on for
another 2 minutes to
ensure complete
polymerization

Indirect bonding using light cured
composites Paul Kasrovi et al AJO 1997
 Brackets bonded on the
cast with laboratory
adhesive
 Bracket height gauges are
are secured in each
bracket slot with Dycal

 Bonding agent
applied on the incisal
portion f the height
gauges
 Small bead of resin is
attached to the each
height gauge to the
incisal edge [occlusal
stop]

The cast is kept in
the triad curing
unit to cure the
resin

Resin tray material is rolled & adapted to the
occlusal stops and cured

 Pumice ,etch &
isolate
 Apply light cure
resin to the back
of the brackets &
seat the tray
firmly

 Remove excess bonding
material around the teeth with a
scaler
 Light cure each bracket for 30
seconds
 Ligature cutter is used to cut the
height gauges

Advantages
 Technique is highly predictable
& reproducible
 Visibility and accessibility from
start to finish
 Ability to remove composite
flash before curing

The slot machine & indirect bonding
THOMAS CREEKMORE,RANDY KUNIK AJO 1993
 Anticipated results are frequently not achieved
in PAE
 Inaccurate bracket placement
 Variations in tooth structure
 Variations in the maxilla/mandibular relationship
 Tissue rebound
 Mechanical deficiencies of appliance
 One PAE prescription cannot fit all ortho pts

 The development and refinement of the a system
to vary the orientation of the bracket arch wire
slot relative to the labial surface of each tooth
provides a solution to these problems
 The slot machine was developed to overcome
these deficiencies of the PAE
THOMAS CREEKMORE,RANDY KUNIK AJO 1993

 not really a bracket
placement device
 Rather it orients the arch
wire slot of the bracket
relative to the facial
surface
 Accomplished by holding
the archwire slot
stationary while
manipulating each tooth
to any tip angle , torque,
rotation & height .

 [ orientation templates & rotation guides]

 Once the labial surface is oriented as
desired the bracket
 The bracket which is held stationary by the
arch wire slot is attached to the tooth with
the bonding material
 bonding material then fills the gap between
the bracket base and the tooth

Bonding

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