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Contents
 Adhesive science
 Structure of enamel
 Adv/disadv of banding & bonding
 Direct bonding
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Broad Rationale of Adhesive Science
 Charect. Req.& prop. Of orthod. material
molecular structural
Why do materials cohere at all?
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Broad Rationale of Adhesive Science
 Range of attractive forces that may
operate in & b/w molecules
 Covalent bonds
 Hydrogen bonds
 Weak intermolecular forces
 Self coherent solids
 Gold & waxes
 Welding & brazing
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Broad Rationale of Adhesive Science
 Most other solids (tooth & ortho brackets)
 Surface forces operate very short dist & ↓
rapidly with inverse 6th
– 7th
power of separation
 Solids- micro. rough
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Broad Rationale of Adhesive Science
FLUID AGENT
Contact angle Viscosity
Smaller contact angle
Larger contact angle
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Broad Rationale of Adhesive Science
 PHASE CHANGE
 Physical means
 Chemical setting mechanism
 Dimensionally stable
 Volumetric expansion/shrinkage
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Broad Rationale of Adhesive Science
 Adhesion :-- Attraction b/w unlike molecules
 Cohesion :-- Attraction b/w like molecules
 Mechanical bonding:-- Strong attachment of 2
substances accomplished mechanically rather
than by molecular attraction.
penetration of adhesive into micro & submicro
irregularities
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BONDING= ADHESION+ATTACHMENT
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Enamel
 Highly mineralized tissue
 Hardest tissue in human body
 Clinically visible
 No regenerative capacity
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Morphology of Enamel
Enamel prisms (rods) – 5-12 million
Extend from DEJ to outer surface
Prismless enamel
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Morphology of Enamel
 Longitudinal section under microscope
 Wider – Prisms
 Narrower – Prism tail
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Morphology of Enamel
 Cross section under electron microscope
- Keyhole pattern or fishlike apperance.
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Morphology of Enamel
 Keyhole pattern
 Head – incisal region
 Tail – cervical region
 Prisms contain
hydroxyapatite crystals
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Morphology of Enamel
 Hydroxyapatite crystals
- Run parallel to long axis
of prism and become
perpendicular as they
approach tail.
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Acquired pellicle
 Precipitation of salivary glycoproteins
 Removed by pumicing
 Reform almost immediately
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Factors affecting enamel solubility
 Pre – eruptive factors
 Post – eruptive factors
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Factors affecting enamel solubility
 Pre – eruptive factors
 Affect chemical and histological characteristics
- Hypoplasia
- Hypocalcification
- Fluorosis
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Factors affecting enamel solubility
 Post – eruptive factors
- Topically applied fluorides
- Organic pellicle
- Plaque
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Factors affecting bonding to ideally
etched surface
 Patient Operator
- salivary contamination - oil / water via spray
- contact with lips and - rubbing /touching
tongue etched surface
- exhalation vapor
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Direct Bonding: Past and present
BANDING - W.E. Magill – 1871
Negative factors –
- Time and skill
- Impacted / partially erupted teeth
- Decalcification / discoloration
- Gingival irritation
- Closure of band spaces
- Unaesthetic
- Placement of separators is painful
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The goal was to have brackets, tubes and
other attachments directly cemented on
the tooth surface to eliminate problems
encountered with metal bands.
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Banding preferred to bonding
 Teeth that receive heavy intermittent forces eg.
Upper 1st
molar
 Teeth that need both labial and lingual
attachments
 Teeth with short clinical crowns
 Teeth surfaces difficult to bond eg. Amalgam
rest., Porcelain rest., Fluorosed teeth.www.indiandentalacademy.com
Advantages of bonding
 Esthetics
 Faster and simpler
 Less patient discomfort
 Arch length not increased
 No band space closure
 Partially erupted or
fractured teeth can be controlled
 Lingual orthodontics
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Advantages of bonding
 Interproximal enamel reduction and composite build
up possible
 Bond artificial tooth surface
 Caries risk eliminated
 Bracket may be recycled
 More hygienic www.indiandentalacademy.com
Disadvantages of bonding
 Weaker than bands
 Better access for cleaning
does not guarantee better
 No protection against
interproximal caries
 Rebonding > recementing
Debonding > debanding
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Bonding Procedure
 Cleaning
 Enamel conditioning
moisture control enamel pretreatment
 Sealing
 Bonding
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Cleaning
 Remove organic pellicle and plaque.
 Pumicing using rubber cup / polishing brush
REISNER et al
Buccal surfaces lightly abraded with TC bur at
slow speed (25000rpm) > Pumicing for 10 sec.
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Enamel conditioning
1. Moisture control
 Lip expanders
 Cheek retractor
 Saliva ejectors
 Tongue guards
 Salivary duct
obstructors(dri-angles)
 Cotton or gauze rolls
 Antisialagogues
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Antisialogogues
 Both tab. & injectable solns :
 Banthine
 pro- Banthine
 Atropine sulfate
 Excellent & rapid saliva flow restriction pro-
Banthine---- no longer advised
 Banthine tab. – 50mg/45kg(100lb) body wt. in a
sugar free drink,15 min before bonding
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Enamel conditioning
2.Enamel pretreatment
 Acid etching
 Other alternatives to acid etching
1. Crystal growth
2. Sand blasting / Air abrasion
3. Laser etching
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Acid Etching
 1955 Buonocore - 85% phosphoric acid for
30 sec.
 37% phosphoric acid – 15 - 60 sec
 Nordenvall et al - 15 sec for deciduous & young
permanent teeth
 30 – 60 sec for adult teeth
 Longer periods – less bond strength due to loss
of enamel structure
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Acid Etching
Procedure
 Isolation
 Gentle application of etchant
– should not be rubbed
 Rinsed with water spray
 Dry with moisture and oil free source ( pref with chip
blower)
 Avoid salivary contamination– if it occurs, re etch the
tooth.
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Acid Etching
 Dull frosty white appearance
 Teeth that do not appear dull and frosty white
should be re - etched
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Acid Etching
 Alternative acids for etching
- 10% Phosphoric acid
- 10% Maleic acid
- 2.5% Nitric acid
- Polyacrylic acid
Most widely used is 30 – 50% ( 37%) phosphoric
acid
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Rationale of etching
 Gwinnet, Matsui and Buonocore & others
 Primary attachment mechanism of resin is “resin
tags”.
 Micromechanical bond
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Rationale of etching
 Removes about 3-10 microns of enamel surface
 Etching also increases the wetability and surface
area of the enamel substrate.
 Resin tag penetrate upto the depth of 80 um or
more
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Conc. Of etchant
 Most widely used concns. of phosphoric acid
from 30% - 50% with an application of 30 -60
seconds.
 20 – 50% / 60 sec. Most retentive surface
( Silverstone )
 > 50% phosphoric acid –
Monocalcium phosphate monohydrate
< 27% phosphoric acid
Dicalcium phosphate dihydrate
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Acid for etching
Maleic Phosphoric Nitric acid
10% 37% 2.5%
 Bond st similar similar less effective
 Morphological
pattern similar ‘’
 Depth of etched
surface less
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Patterns of etching
According to Retief
 Type 1
- Selective removal of enamel prism cores
- Peripheries intact (honey comb app.)
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Patterns of etching
 Type 2
- Reverse process
- Peripheries removed
- Cores intact (cobble stone app.)
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Patterns of etching
 Type 3
- surface loss w/o exposing underlying prisms
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Effects of enamel etching time on
morphology
Barkmeier,Gwinnett & Shaffer JCO January
1985
 The morphology of enamel following etching for
15 or 60 secs. differed only in the amount of
gross enamel loss with 50% phosphoric acid
 No morphological differences in the pattern or
character of the etched enamel rods.
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Bond strength with various etching
times
Wang et al AJO-DO July 1991
 Compared the tensile bond strength at various
etching times 15, 30, 60, 90, 120 secs
 37% Phosphoric acid
 TBS was not statistically different for 15, 30, 60,
90 secs
 TBS decreased – 120 secs
 Amount of enamel fragments increased in
proportion to the length of the etching times
 Optimal etching time should be 15sec
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SEM Study & SBS measurement with
5% & 37% phosphoric acid
AJO-DO oct,1995
Wasundhara A. Bhad, Pushpa V. Hazarey,
G.D.C.Nagpur
 PURPOSE: To use an acid concn. Of H3PO4 that
yielded max. bond strength with minimal enamel
loss & to measure & compare the SBS b/w 5% &
37% H3PO4 with 60 sec acid etching time.
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 SAMPLE: 60 Premolars
 1st
grp  10 teeth, used to study etching pattern with
5% & 37% H3PO4
 2nd
grp  50 teeth, used to study & compare SBS
after etching with 5% & 37% H3PO4
 CONCLUSION:
 5%H3PO4 can be used for etching tooth surface
before bonding instead of 37% H3PO4 concn; as with
5%H3PO4, there is minimal enamel loss & bond
strength is not affectedwww.indiandentalacademy.com
Variations in acid-etch patterns with
different acids and etch times
Alastair Gardner, Ross Hobson, AJO 2001
 Compared the enamel etch patterns produced by
37% phosphoric acid and 2.5% Nitric acid for 15,
30 & 60 secs
 Concluded
- 37% phosphoric acid > 2.5% nitric acid for all
three applications
-optimum time for applying 37% phosphoric acid is
30 sec
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Acid etching in pri. teeth
 Outer 30um of pri. Enamel is prism less  no
uniform etch
 Higher organic content
 Prism rods approach the surface at greater
angle
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Acid etching in pri. teeth
 STUDIES:
 SILVERSTONE:- 120 sec etch necessary to
establish proper enamel porosity
 MUELLER(1977):- By increasing the etch time
an increase in tag formation was seen
 NORDENVELL et al :- Compared pri. Young &
mature perm. Teeth using var. etch times b/w
15-60 sec. found that 15 sec gave greatest
surface irreg. in pri. teeth.
 REDFORD:- etch time of 15 sec with 38% phos
acid was adeq for pri. teeth.
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Commonly asked questions
 Should the etch cover the entire facial enamel or
only a small portion outside the bracket pad?
 Are gels preferable to solutions?
 What is the optimal etching time? Is it different for
young and old teeth?
 Is sandblasting as effective as acid etching?
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 What is the preferred procedure for deciduous
teeth?
 Is prolonged etching necessary when teeth are
pretreated with fluoride?
 Will incorporation of fluorides in the etching soln
increase the resistance of enamel to caries attack?
 Is etching permissible on teeth with internal white
spots? www.indiandentalacademy.com
 How much enamel is removed by etching and how
deep are the histologic alterations? Are they
reversible? Is etching harmful?
 Should other means than acid etching( e.g. crystal
growth ) be preferred?
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Alternatives to acid etching
 Crystal growth
 Sand blasting / Air abrasion
 Laser etching
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Iatrogenic factors
Maijer & Smith 1986 AJO-DO
1.Loss of enamel caused by etching
 10-20 um lost - acid etch
 6-50 um lost - after debonding
2.Retention of resin tags – discoloration of enamel
 Resin tags – 80um or more
 U/V cured resin – didn’t contain u/v absorber
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Iatrogenic factors
Maijer & Smith 1986 AJO-DO
3.Leakage at the bracket interface Bracket
corrosion and staining
 Small pores – pathway for bact., stains etc.
 Ceen & gwinnett and maijer & smith – stain due
to biodgradation of the metals
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Iatrogenic factors
Maijer & Smith 1986 AJO-DO
4.Enamel loss  fracturing of enamel at time of
debonding.
 Reported by Reteif(1974) and Reteif &
Denys(1979)
5.A rougher surface with enamel cracks
 2 step procedure should be used
 1st
step – debonding pliers,hand instru,u/s
scalers
 2nd
step – abrasive cups/discs with polishing
medium
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Iatrogenic factors
Maijer & Smith 1986 AJO-DO
6.A softer enamel surface with lower fluoride
content, more predisposed to decalcification
 Acquired fluoride – 10um
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Crystal growth
 1st
demonstrated by Smith & Cartz
 Maijer & Smith 1979 did lot of work
 Polyacrylic acid + sulfate ion long needle
shaped crystaline deposit
 CALCIUM SULPHATE DIHYDRATE (Spherulitic
habit)
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Crystal growth
 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 )
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Crystal growth
 MECHANISM OF RETENTION
 Calcium sulphate 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.
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Crystal growth
 Artun and Bergland 1984
 Sulphuric acid – crystals not as long and needle
like as with polyacrylic acid but were rounder and
flatter.
 Hence debonding was easier.
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Advantages of Crystal growth
 Debonding quicker and easier
 No damage to enamel
 Minimal effect on outer fluoride containing enamel
 No resin tags left behind
 Possibility of incorporating fluoride in crystal interface
– anticariogenic action.
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Crystal growth – Procedure
 One drop of viscous liquid placed on tooth surface
 Left undisturbed for 30 sec
 No mechanical agitation
 Rinsed for 20 sec
 Forceful water spray to be avoided as it will break
crystals
 Dull whitish deposit
 Bracket bonded in usual way.
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Alternatives to acid etching
 Crystal growth
 Sand blasting / Air abrasion
 Laser etching
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Sand blasting / Air abrasion
 Makes use of high speed stream of aluminium
oxide particles ( 50-90 um) propelled by air
pressure
 Produces rough surface
 Used for cavity preparation
 Remove old composite resin
 Improve the retentive surface of loose bracket
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Sand blasting / Air abrasion
 Could contribute to better bond strength with
less enamel loss
 Factors affecting bond strength
 Particle size
 Air pressure
 Exposure time
 Microstructure of enamel surface
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Sand blasting
Albert Feilzer,AJO Jan 2000
Compared bond strength and enamel loss b/w
sand blasting and conventional acid etching at
varying exposure times and air pressure
Enamel loss – equal or less depend on time of
exposure and pressure
Bond strength –
Sand blasting < Acid etching
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Conclusion
Sandblasting Acid etching Crystal growth
 Enamel loss
controlled by operator remineralized less
 Bond strength
low than A E Optimum low than A E
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Alternatives to acid etching
 Crystal growth
 Sand blasting / Air abrasion
 Laser etching
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Laser etching
 LASER – Light Amplification by Stimulated
Emission of Radiation
 Maiman 1960 – developed first laser
 Generation of monochromatic, coherent &
collimated radiation by a suitable laser medium in a
optical resonator
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Laser etching
 Laser unit – 3 elements
1.Lasing medium - liquid/solid/gas
2.Energy source - xenon flash lamp/electrical
discharge
3.Optical resonator- 3prop.
 coherence
 collimation
 monochromacity
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Laser etching
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Laser etching
USE OF LASER SYSTEM
 Soft & hard tissue lesions t/t
 Caries prevention
 Desensitization of teeth
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Laser etching
Classification
 According wavelength
1. UV range ( Krypton
fluoride, Argon fluoride)
2. Visible light ( Helium
Neon, argon laser )
3. Infrared range (carbon
dioxide , Nd: YAG )
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Laser etching of enamel for direct
bonding Von Fraunhofer 1993, No.1 AO
 Phosphoric acid – 30 sec.
 4 power settings on the laser etching unit were used:
80mJ, 1W, 2W and 3W.
 Melting and ablation of enamel surface (roughness)
Result
 Acceptable shear bond strength,(0.6kg/mm), could
achieved at laser power settings of 1 to 3W but not at
the lowest setting (80 mJ).
 Shear bond strengths lower than acid etching.
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Laser etching
Dr. Francis 2001
 Aim – to compare tensile & shear bond strength
obtained by acid etching & krypton flouride excimer
laser.
 KrF(440MJ/cms, 460 and 480)
 Optimum bond strength achieved with 460 & 480
 TBS - highest with 460 then480 & acid etching
 SBS- highest with 480
 both Least with 440
 Adhesive more on E with acid etching
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Bonding Procedure
 Cleaning
 Enamel conditioning
- Acid etching
- Crystal growth
- Sandblasting
- Laser etching
 Sealing
 Bonding
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Sealing
 Sealer / Primer / Intermediate resin
Low viscosity resin which is applied prior to bonding
VARIOUS CONCEPTS
Necessary to achieve proper bond strength
Resist. to microleakage
Both reasons
Not needed at all
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Sealing
 Sealants 2 types
 light cured
 chemically cured
CEEN & GWINNETT
Light cured sealant protect the enamel adjacent to
the brackets from dissolution & subsurface
lesions
Chemically cured polymerize poorly & have low
resist. to abrasion
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Evaluation of sealant in Orthodontic
bonding
Wei Nan Wang et al AJO 1991
 Evaluated the TBS with & w/o use of sealant
 No statistically significant difference in the bond
strength of the two evaluated groups
 The distributions of debonding interface between
groups were similar and also had no statistical
difference.
 Sealant in the two-paste self polymerize bonding
system for enhanced strength is unnecessary.www.indiandentalacademy.com
Sealing
 However the use of sealant
 May offer extra protection to enamel during
debonding
 As chances of enamel surface detachment
without use of sealant was greater.
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Self Etch Primer
 Traditional orthodontic bonding systems
 Fourth-generation bonding systems such as(All-
Bond 2)
 Fifth-generation bonding (Prime & Bond NT)
Etchant & Primer + Adhesive into one step.
 Sixth-generation adhesive (Prompt L-Pop,
Transbond Plus Self Etching Primer)
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Self Etch Primer
 Prompt L Pop
 Transbond self etch primer
Liquid begins to etch as soon as it is applied
Saves time www.indiandentalacademy.com
Self Etch Primer
Composition of Prompt L-Pop –
 Methacrylate phosphoric acid ester
 Phosphine oxide
 Parabenes
 Stabilizer
 A fluoride complex
 Water
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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.www.indiandentalacademy.com
Procedure for self etch primer
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Self Etch Primer - studies
 Rueggeberg et al (2000) - promt L-Pop w/o acid
etch produce = bond strength as conventional
bracket placement
 Hitmi (2000)- no signi. diff b/w promt L-Pop &
37% phosphoric acid
 Bergeron et al (2000)- resin enamel bond
strength of diff self etching primer including
promt L-Pop, was similar to or better than
multistep
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Self Etch Primer - studies
 Fritz et al(2001)- bonding with 3 self etching
primer(Clearfil SE Bond,Clearfil Liner Bond 2V&
Novabond)was = phos acid
 Bishara et al(2001)- self etching primer prod a
signi lower, but clinic acceptable, SBS compared
to acid etch when Transbond XT composite
used
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Self Etch Primer - studies
 SHADOW ET AL (2002 JCO)
 clinical eval. bond failure rates with a new self
ething primer- Transbond Plus
 Conclusion
 Traditional AE 15 sec = etch & 15-20 sec =
rinsing.10 sec= primer + curing
 Transbond Plus =3 sec
 Bracket retention > traditional
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Hydrophilic Primer ( MIP )
 Bond failure – moisture contamination
 Hormati et al – 50% decreased shear bond st
 Hydrophilic primer ( HEMA & Maleic acid )dissolved
in acetone – 3M Unitek.
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Hydrophilic Primer ( MIP )
S.J. Little Wood et al JO 2000
 Compared the bond strength of bracket bonded with
hydrophilic primer with conventional primer
 Bond strength (6.43) was lower than conventional
primer (8.71)
 Bracket bonded with hydrophilic primer were 3.96
times more at risk of failure.
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Pre primed brackets
 ADVANTAGES:
 Consistent quality of adhesive
 Reduced flash
 Adequate bond strength
 Less chances of contamination
 Can be used in both direct & indirect tech.
 Both metal & ceramic brackets are available
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Bonding Procedure
 Cleaning
 Enamel conditioning
- Acid etching
- Crystal growth
- Sandblasting
- Laser etching
 Sealing
 Bonding
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Bonding Procedure
Four steps
1. Transfer
2. Positioning
3. Fitting
4. Removal of excess
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Bonding
 TRANSFER
 Adhesive put on
bracket base
 Bracket placed on the
tooth closed to the
correct position
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Bonding
 POSITIONING
 Proper vertical and
horizontal
positioning
( eg Using
placement scaler
with parallel edges)
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Bonding
 FITTING
 Bracket firmly
pushed towards
the tooth surface
with one point
contact
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Bonding
REMOVAL OF EXCESS
 Gingival irritation
 Plaque build up
 Better esthetics
 Prevents staining and
discoloration
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Bonding to Fluorosed teeth
Dr.Veeresh
 Bonding to the fluorosed teeth is difficult with
conventional acid etching.
 Aim – to evaluate the shear bond strength of the
bracket to the fluorosed teeth by using a comb. of
sandblasting & acid etching
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Bonding to Fluorosed teeth
 Group 1 – acid etching
 Group 2 – sandblasting
 Group 3 - acid etching followed by sandblasting
 Group 4 – sandblasting then acid etching
Results
 Only group 4 – Bond strength slightly higher than
optimum (8.1Mpa)
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Curing Lights
 Tungsten quartz halogen light
 Argon laser
 Xenon plasma arc light
 Light emitting diode curing units ( LED )
 Pulsed xenon plasma arc light
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Halogen Tungsten Quartz Curing
Light
 Bulb  quartz
 Filament  Tungsten
 Gas  Halogen
Selective filters – blue light ( 400-500 micron)
 40 seconds per bracket
 15 minutes – both arches
www.indiandentalacademy.com
Halogen Tungsten Quartz Curing
Light
Disadvantages
 Curing is time consuming
 Light output < 1% of consumed electricity
 Lifetime – 100hrs
 High heat - degrades components of bulb
www.indiandentalacademy.com
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
www.indiandentalacademy.com
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 www.indiandentalacademy.com
Xenon plasma arc light
 Introduced in late 1990’s
 Short exposure time at lower cost
 Curing time – 3-5 sec per bracket
 Higher intensity than conventional
 Expensive – argon laser > xenon plasma >
conventional light.www.indiandentalacademy.com
Comparison of efficiency of xenon
plasma light and conventional 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 secs www.indiandentalacademy.com
Light emitting diode curing units
Mills –1995
 Instead of hot filament – Halogen bulb.
 LED – junction of doped semi conductors.
www.indiandentalacademy.com
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 www.indiandentalacademy.com
Light emitting diode curing units
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
www.indiandentalacademy.com
Light emitting diode curing units
 Disadvantages
 Their technology is new to orthodontics,
and the concept still is evolving.
 Their curing time is slower than plasma
arc curing lights and some enhanced
halogen lights. www.indiandentalacademy.com
Light emitting diode curing units
 Disadvantages
 Their batteries must be recharged.
 They cost more than do conventional
halogen lights.
 They offer a relatively low intensity.
www.indiandentalacademy.com
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 .
 No diff in bond strength of orthodontic
brackets bonded to teeth with conventional
halogen light and LED curing units .
www.indiandentalacademy.com
Light Emitting Diode Units
Dr.Ravitej
 Aim - Shear Bond Strength Evaluation of three
commercially Available Light Emitting Diode
Units
 The 3 different LED sources used in the study
1. Elipar Freelight (3M/ESPE)
2. Bee Cool (Confident dental equipments,
Bangalore)
3. Apoza (Meghna and Co., Bangalore)
www.indiandentalacademy.com
3 different LED sources used in the study
1. Elipar Freelight (3M/ESPE)
2. Bee Cool (Confident dental equipments,
Bangalore)
3. Apoza (Meghna and Co., Bangalore)
www.indiandentalacademy.com
 Study sample -- 70 non-carious extracted
upper premolar teeth
 Divided into 7 groups of 10 each
 Group I Group II-IV Group V-VII
Elipar Freelight Bee Cool (Confident) Apoza
Results
Bond strength of G I and G IV samples fall in the
optimal range.
Bond strength values of other groups were
suboptimal.
www.indiandentalacademy.com
 Group I sample (Elipar Freelight-10s,
3M/ESPE) can be considered most suitable
 Group IV sample (Bee Cool-20s, Confident
dental equipments, Bangalore) can also be
considered appropriate
www.indiandentalacademy.com
References
 Orthodontics current principles & techniques: Graber
& Vanarsdall, 3rd
Ed
 Philip’s science of dental materials 11th
Ed
 Contemporary orthodontics: Proffit 3rd
Ed
 Orthodontic Materials Scientific & Clinical Aspects:
William A. Brantley,Theodore Eliades
 SEM Study & SBS measurement with 5% & 37%
phosphoric acid - AJO-DO oct,1995
Wasundhara A. Bhad, Pushpa V. Hazarey,
G.D.C.Nagpur
www.indiandentalacademy.com
References
 Air abrasion tech vs conventional acid etching
tech.- AJO-DO Jan 2000- Wandela L. et al
 Laser etching of enamel for direct bonding-
AO,1993 no.1- Von Fraunhofer et al
 Clinical trials with crystal growth- AJO-DO Apr
1984 – Artun and Bergland
 crystal growth on outer enamel surface- AJO-DO
March 1986- Maijer & Smith
 Thesis on Laser etching - Dr. Francis
 Thesis on Bonding to Fluorosed teeth -
Dr.Veeresh www.indiandentalacademy.com
References
 Bond strength with various etching times on
young perm teeth- AJO-DO Jul 1991- Wang &
Chau Lu
 Effect of enamel etching time on bond strength
& morphology- JCO Jan 1985- Wayne et al
 Lab.& clinical evaluation of self etching primer
JCO Jan 2001- Robert A. Miller
 Variation in acid etch patterns with diff acids &
etch time AJO-DO Jul 2001- Alastair Gardner et
al
www.indiandentalacademy.com
References
 Clinical evaluation of bond failure rates with a
new self etching primer- JCO Dec 2002-
Shadow Asgari et al
 Rapid curing of bonding with xenon plasma arc
light - AJO-DO Jun 2001- Oesterle, Sheldon,
Newman et al
 Evaluation of sealant in ortho bonding- AJO-DO
Sep 1991- Wei Nan Wang
 Bond strength comparison of MIP- AJO-DO Sep
2002- Shane & Timothy
www.indiandentalacademy.com

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Ash bonding

  • 2. Contents  Adhesive science  Structure of enamel  Adv/disadv of banding & bonding  Direct bonding www.indiandentalacademy.com
  • 3. Broad Rationale of Adhesive Science  Charect. Req.& prop. Of orthod. material molecular structural Why do materials cohere at all? www.indiandentalacademy.com
  • 4. Broad Rationale of Adhesive Science  Range of attractive forces that may operate in & b/w molecules  Covalent bonds  Hydrogen bonds  Weak intermolecular forces  Self coherent solids  Gold & waxes  Welding & brazing www.indiandentalacademy.com
  • 5. Broad Rationale of Adhesive Science  Most other solids (tooth & ortho brackets)  Surface forces operate very short dist & ↓ rapidly with inverse 6th – 7th power of separation  Solids- micro. rough www.indiandentalacademy.com
  • 6. Broad Rationale of Adhesive Science FLUID AGENT Contact angle Viscosity Smaller contact angle Larger contact angle www.indiandentalacademy.com
  • 7. Broad Rationale of Adhesive Science  PHASE CHANGE  Physical means  Chemical setting mechanism  Dimensionally stable  Volumetric expansion/shrinkage www.indiandentalacademy.com
  • 8. Broad Rationale of Adhesive Science  Adhesion :-- Attraction b/w unlike molecules  Cohesion :-- Attraction b/w like molecules  Mechanical bonding:-- Strong attachment of 2 substances accomplished mechanically rather than by molecular attraction. penetration of adhesive into micro & submicro irregularities www.indiandentalacademy.com
  • 10. Enamel  Highly mineralized tissue  Hardest tissue in human body  Clinically visible  No regenerative capacity www.indiandentalacademy.com
  • 11. Morphology of Enamel Enamel prisms (rods) – 5-12 million Extend from DEJ to outer surface Prismless enamel www.indiandentalacademy.com
  • 12. Morphology of Enamel  Longitudinal section under microscope  Wider – Prisms  Narrower – Prism tail www.indiandentalacademy.com
  • 13. Morphology of Enamel  Cross section under electron microscope - Keyhole pattern or fishlike apperance. www.indiandentalacademy.com
  • 14. Morphology of Enamel  Keyhole pattern  Head – incisal region  Tail – cervical region  Prisms contain hydroxyapatite crystals www.indiandentalacademy.com
  • 15. Morphology of Enamel  Hydroxyapatite crystals - Run parallel to long axis of prism and become perpendicular as they approach tail. www.indiandentalacademy.com
  • 16. Acquired pellicle  Precipitation of salivary glycoproteins  Removed by pumicing  Reform almost immediately www.indiandentalacademy.com
  • 17. Factors affecting enamel solubility  Pre – eruptive factors  Post – eruptive factors www.indiandentalacademy.com
  • 18. Factors affecting enamel solubility  Pre – eruptive factors  Affect chemical and histological characteristics - Hypoplasia - Hypocalcification - Fluorosis www.indiandentalacademy.com
  • 19. Factors affecting enamel solubility  Post – eruptive factors - Topically applied fluorides - Organic pellicle - Plaque www.indiandentalacademy.com
  • 20. Factors affecting bonding to ideally etched surface  Patient Operator - salivary contamination - oil / water via spray - contact with lips and - rubbing /touching tongue etched surface - exhalation vapor www.indiandentalacademy.com
  • 21. Direct Bonding: Past and present BANDING - W.E. Magill – 1871 Negative factors – - Time and skill - Impacted / partially erupted teeth - Decalcification / discoloration - Gingival irritation - Closure of band spaces - Unaesthetic - Placement of separators is painful www.indiandentalacademy.com
  • 22. The goal was to have brackets, tubes and other attachments directly cemented on the tooth surface to eliminate problems encountered with metal bands. www.indiandentalacademy.com
  • 23. Banding preferred to bonding  Teeth that receive heavy intermittent forces eg. Upper 1st molar  Teeth that need both labial and lingual attachments  Teeth with short clinical crowns  Teeth surfaces difficult to bond eg. Amalgam rest., Porcelain rest., Fluorosed teeth.www.indiandentalacademy.com
  • 24. Advantages of bonding  Esthetics  Faster and simpler  Less patient discomfort  Arch length not increased  No band space closure  Partially erupted or fractured teeth can be controlled  Lingual orthodontics www.indiandentalacademy.com
  • 25. Advantages of bonding  Interproximal enamel reduction and composite build up possible  Bond artificial tooth surface  Caries risk eliminated  Bracket may be recycled  More hygienic www.indiandentalacademy.com
  • 26. Disadvantages of bonding  Weaker than bands  Better access for cleaning does not guarantee better  No protection against interproximal caries  Rebonding > recementing Debonding > debanding www.indiandentalacademy.com
  • 27. Bonding Procedure  Cleaning  Enamel conditioning moisture control enamel pretreatment  Sealing  Bonding www.indiandentalacademy.com
  • 28. Cleaning  Remove organic pellicle and plaque.  Pumicing using rubber cup / polishing brush REISNER et al Buccal surfaces lightly abraded with TC bur at slow speed (25000rpm) > Pumicing for 10 sec. www.indiandentalacademy.com
  • 29. Enamel conditioning 1. Moisture control  Lip expanders  Cheek retractor  Saliva ejectors  Tongue guards  Salivary duct obstructors(dri-angles)  Cotton or gauze rolls  Antisialagogues www.indiandentalacademy.com
  • 30. Antisialogogues  Both tab. & injectable solns :  Banthine  pro- Banthine  Atropine sulfate  Excellent & rapid saliva flow restriction pro- Banthine---- no longer advised  Banthine tab. – 50mg/45kg(100lb) body wt. in a sugar free drink,15 min before bonding www.indiandentalacademy.com
  • 31. Enamel conditioning 2.Enamel pretreatment  Acid etching  Other alternatives to acid etching 1. Crystal growth 2. Sand blasting / Air abrasion 3. Laser etching www.indiandentalacademy.com
  • 32. Acid Etching  1955 Buonocore - 85% phosphoric acid for 30 sec.  37% phosphoric acid – 15 - 60 sec  Nordenvall et al - 15 sec for deciduous & young permanent teeth  30 – 60 sec for adult teeth  Longer periods – less bond strength due to loss of enamel structure www.indiandentalacademy.com
  • 33. Acid Etching Procedure  Isolation  Gentle application of etchant – should not be rubbed  Rinsed with water spray  Dry with moisture and oil free source ( pref with chip blower)  Avoid salivary contamination– if it occurs, re etch the tooth. www.indiandentalacademy.com
  • 34. Acid Etching  Dull frosty white appearance  Teeth that do not appear dull and frosty white should be re - etched www.indiandentalacademy.com
  • 35. Acid Etching  Alternative acids for etching - 10% Phosphoric acid - 10% Maleic acid - 2.5% Nitric acid - Polyacrylic acid Most widely used is 30 – 50% ( 37%) phosphoric acid www.indiandentalacademy.com
  • 36. Rationale of etching  Gwinnet, Matsui and Buonocore & others  Primary attachment mechanism of resin is “resin tags”.  Micromechanical bond www.indiandentalacademy.com
  • 37. Rationale of etching  Removes about 3-10 microns of enamel surface  Etching also increases the wetability and surface area of the enamel substrate.  Resin tag penetrate upto the depth of 80 um or more www.indiandentalacademy.com
  • 38. Conc. Of etchant  Most widely used concns. of phosphoric acid from 30% - 50% with an application of 30 -60 seconds.  20 – 50% / 60 sec. Most retentive surface ( Silverstone )  > 50% phosphoric acid – Monocalcium phosphate monohydrate < 27% phosphoric acid Dicalcium phosphate dihydrate www.indiandentalacademy.com
  • 39. Acid for etching Maleic Phosphoric Nitric acid 10% 37% 2.5%  Bond st similar similar less effective  Morphological pattern similar ‘’  Depth of etched surface less www.indiandentalacademy.com
  • 40. Patterns of etching According to Retief  Type 1 - Selective removal of enamel prism cores - Peripheries intact (honey comb app.) www.indiandentalacademy.com
  • 41. Patterns of etching  Type 2 - Reverse process - Peripheries removed - Cores intact (cobble stone app.) www.indiandentalacademy.com
  • 42. Patterns of etching  Type 3 - surface loss w/o exposing underlying prisms www.indiandentalacademy.com
  • 43. Effects of enamel etching time on morphology Barkmeier,Gwinnett & Shaffer JCO January 1985  The morphology of enamel following etching for 15 or 60 secs. differed only in the amount of gross enamel loss with 50% phosphoric acid  No morphological differences in the pattern or character of the etched enamel rods. www.indiandentalacademy.com
  • 44. Bond strength with various etching times Wang et al AJO-DO July 1991  Compared the tensile bond strength at various etching times 15, 30, 60, 90, 120 secs  37% Phosphoric acid  TBS was not statistically different for 15, 30, 60, 90 secs  TBS decreased – 120 secs  Amount of enamel fragments increased in proportion to the length of the etching times  Optimal etching time should be 15sec www.indiandentalacademy.com
  • 45. SEM Study & SBS measurement with 5% & 37% phosphoric acid AJO-DO oct,1995 Wasundhara A. Bhad, Pushpa V. Hazarey, G.D.C.Nagpur  PURPOSE: To use an acid concn. Of H3PO4 that yielded max. bond strength with minimal enamel loss & to measure & compare the SBS b/w 5% & 37% H3PO4 with 60 sec acid etching time. www.indiandentalacademy.com
  • 46.  SAMPLE: 60 Premolars  1st grp  10 teeth, used to study etching pattern with 5% & 37% H3PO4  2nd grp  50 teeth, used to study & compare SBS after etching with 5% & 37% H3PO4  CONCLUSION:  5%H3PO4 can be used for etching tooth surface before bonding instead of 37% H3PO4 concn; as with 5%H3PO4, there is minimal enamel loss & bond strength is not affectedwww.indiandentalacademy.com
  • 47. Variations in acid-etch patterns with different acids and etch times Alastair Gardner, Ross Hobson, AJO 2001  Compared the enamel etch patterns produced by 37% phosphoric acid and 2.5% Nitric acid for 15, 30 & 60 secs  Concluded - 37% phosphoric acid > 2.5% nitric acid for all three applications -optimum time for applying 37% phosphoric acid is 30 sec www.indiandentalacademy.com
  • 48. Acid etching in pri. teeth  Outer 30um of pri. Enamel is prism less  no uniform etch  Higher organic content  Prism rods approach the surface at greater angle www.indiandentalacademy.com
  • 49. Acid etching in pri. teeth  STUDIES:  SILVERSTONE:- 120 sec etch necessary to establish proper enamel porosity  MUELLER(1977):- By increasing the etch time an increase in tag formation was seen  NORDENVELL et al :- Compared pri. Young & mature perm. Teeth using var. etch times b/w 15-60 sec. found that 15 sec gave greatest surface irreg. in pri. teeth.  REDFORD:- etch time of 15 sec with 38% phos acid was adeq for pri. teeth. www.indiandentalacademy.com
  • 50. Commonly asked questions  Should the etch cover the entire facial enamel or only a small portion outside the bracket pad?  Are gels preferable to solutions?  What is the optimal etching time? Is it different for young and old teeth?  Is sandblasting as effective as acid etching? www.indiandentalacademy.com
  • 51.  What is the preferred procedure for deciduous teeth?  Is prolonged etching necessary when teeth are pretreated with fluoride?  Will incorporation of fluorides in the etching soln increase the resistance of enamel to caries attack?  Is etching permissible on teeth with internal white spots? www.indiandentalacademy.com
  • 52.  How much enamel is removed by etching and how deep are the histologic alterations? Are they reversible? Is etching harmful?  Should other means than acid etching( e.g. crystal growth ) be preferred? www.indiandentalacademy.com
  • 53. Alternatives to acid etching  Crystal growth  Sand blasting / Air abrasion  Laser etching www.indiandentalacademy.com
  • 54. Iatrogenic factors Maijer & Smith 1986 AJO-DO 1.Loss of enamel caused by etching  10-20 um lost - acid etch  6-50 um lost - after debonding 2.Retention of resin tags – discoloration of enamel  Resin tags – 80um or more  U/V cured resin – didn’t contain u/v absorber www.indiandentalacademy.com
  • 55. Iatrogenic factors Maijer & Smith 1986 AJO-DO 3.Leakage at the bracket interface Bracket corrosion and staining  Small pores – pathway for bact., stains etc.  Ceen & gwinnett and maijer & smith – stain due to biodgradation of the metals www.indiandentalacademy.com
  • 56. Iatrogenic factors Maijer & Smith 1986 AJO-DO 4.Enamel loss  fracturing of enamel at time of debonding.  Reported by Reteif(1974) and Reteif & Denys(1979) 5.A rougher surface with enamel cracks  2 step procedure should be used  1st step – debonding pliers,hand instru,u/s scalers  2nd step – abrasive cups/discs with polishing medium www.indiandentalacademy.com
  • 57. Iatrogenic factors Maijer & Smith 1986 AJO-DO 6.A softer enamel surface with lower fluoride content, more predisposed to decalcification  Acquired fluoride – 10um www.indiandentalacademy.com
  • 58. Crystal growth  1st demonstrated by Smith & Cartz  Maijer & Smith 1979 did lot of work  Polyacrylic acid + sulfate ion long needle shaped crystaline deposit  CALCIUM SULPHATE DIHYDRATE (Spherulitic habit) www.indiandentalacademy.com
  • 59. Crystal growth  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 ) www.indiandentalacademy.com
  • 60. Crystal growth  MECHANISM OF RETENTION  Calcium sulphate 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. www.indiandentalacademy.com
  • 61. Crystal growth  Artun and Bergland 1984  Sulphuric acid – crystals not as long and needle like as with polyacrylic acid but were rounder and flatter.  Hence debonding was easier. www.indiandentalacademy.com
  • 62. Advantages of Crystal growth  Debonding quicker and easier  No damage to enamel  Minimal effect on outer fluoride containing enamel  No resin tags left behind  Possibility of incorporating fluoride in crystal interface – anticariogenic action. www.indiandentalacademy.com
  • 63. Crystal growth – Procedure  One drop of viscous liquid placed on tooth surface  Left undisturbed for 30 sec  No mechanical agitation  Rinsed for 20 sec  Forceful water spray to be avoided as it will break crystals  Dull whitish deposit  Bracket bonded in usual way. www.indiandentalacademy.com
  • 64. Alternatives to acid etching  Crystal growth  Sand blasting / Air abrasion  Laser etching www.indiandentalacademy.com
  • 65. Sand blasting / Air abrasion  Makes use of high speed stream of aluminium oxide particles ( 50-90 um) propelled by air pressure  Produces rough surface  Used for cavity preparation  Remove old composite resin  Improve the retentive surface of loose bracket www.indiandentalacademy.com
  • 66. Sand blasting / Air abrasion  Could contribute to better bond strength with less enamel loss  Factors affecting bond strength  Particle size  Air pressure  Exposure time  Microstructure of enamel surface www.indiandentalacademy.com
  • 67. Sand blasting Albert Feilzer,AJO Jan 2000 Compared bond strength and enamel loss b/w sand blasting and conventional acid etching at varying exposure times and air pressure Enamel loss – equal or less depend on time of exposure and pressure Bond strength – Sand blasting < Acid etching www.indiandentalacademy.com
  • 68. Conclusion Sandblasting Acid etching Crystal growth  Enamel loss controlled by operator remineralized less  Bond strength low than A E Optimum low than A E www.indiandentalacademy.com
  • 69. Alternatives to acid etching  Crystal growth  Sand blasting / Air abrasion  Laser etching www.indiandentalacademy.com
  • 70. Laser etching  LASER – Light Amplification by Stimulated Emission of Radiation  Maiman 1960 – developed first laser  Generation of monochromatic, coherent & collimated radiation by a suitable laser medium in a optical resonator www.indiandentalacademy.com
  • 71. Laser etching  Laser unit – 3 elements 1.Lasing medium - liquid/solid/gas 2.Energy source - xenon flash lamp/electrical discharge 3.Optical resonator- 3prop.  coherence  collimation  monochromacity www.indiandentalacademy.com
  • 73. Laser etching USE OF LASER SYSTEM  Soft & hard tissue lesions t/t  Caries prevention  Desensitization of teeth www.indiandentalacademy.com
  • 74. Laser etching Classification  According wavelength 1. UV range ( Krypton fluoride, Argon fluoride) 2. Visible light ( Helium Neon, argon laser ) 3. Infrared range (carbon dioxide , Nd: YAG ) www.indiandentalacademy.com
  • 75. Laser etching of enamel for direct bonding Von Fraunhofer 1993, No.1 AO  Phosphoric acid – 30 sec.  4 power settings on the laser etching unit were used: 80mJ, 1W, 2W and 3W.  Melting and ablation of enamel surface (roughness) Result  Acceptable shear bond strength,(0.6kg/mm), could achieved at laser power settings of 1 to 3W but not at the lowest setting (80 mJ).  Shear bond strengths lower than acid etching. www.indiandentalacademy.com
  • 76. Laser etching Dr. Francis 2001  Aim – to compare tensile & shear bond strength obtained by acid etching & krypton flouride excimer laser.  KrF(440MJ/cms, 460 and 480)  Optimum bond strength achieved with 460 & 480  TBS - highest with 460 then480 & acid etching  SBS- highest with 480  both Least with 440  Adhesive more on E with acid etching www.indiandentalacademy.com
  • 77. Bonding Procedure  Cleaning  Enamel conditioning - Acid etching - Crystal growth - Sandblasting - Laser etching  Sealing  Bonding www.indiandentalacademy.com
  • 78. Sealing  Sealer / Primer / Intermediate resin Low viscosity resin which is applied prior to bonding VARIOUS CONCEPTS Necessary to achieve proper bond strength Resist. to microleakage Both reasons Not needed at all www.indiandentalacademy.com
  • 79. Sealing  Sealants 2 types  light cured  chemically cured CEEN & GWINNETT Light cured sealant protect the enamel adjacent to the brackets from dissolution & subsurface lesions Chemically cured polymerize poorly & have low resist. to abrasion www.indiandentalacademy.com
  • 80. Evaluation of sealant in Orthodontic bonding Wei Nan Wang et al AJO 1991  Evaluated the TBS with & w/o use of sealant  No statistically significant difference in the bond strength of the two evaluated groups  The distributions of debonding interface between groups were similar and also had no statistical difference.  Sealant in the two-paste self polymerize bonding system for enhanced strength is unnecessary.www.indiandentalacademy.com
  • 81. Sealing  However the use of sealant  May offer extra protection to enamel during debonding  As chances of enamel surface detachment without use of sealant was greater. www.indiandentalacademy.com
  • 82. Self Etch Primer  Traditional orthodontic bonding systems  Fourth-generation bonding systems such as(All- Bond 2)  Fifth-generation bonding (Prime & Bond NT) Etchant & Primer + Adhesive into one step.  Sixth-generation adhesive (Prompt L-Pop, Transbond Plus Self Etching Primer) www.indiandentalacademy.com
  • 83. Self Etch Primer  Prompt L Pop  Transbond self etch primer Liquid begins to etch as soon as it is applied Saves time www.indiandentalacademy.com
  • 84. Self Etch Primer Composition of Prompt L-Pop –  Methacrylate phosphoric acid ester  Phosphine oxide  Parabenes  Stabilizer  A fluoride complex  Water www.indiandentalacademy.com
  • 85. 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.www.indiandentalacademy.com
  • 86. Procedure for self etch primer www.indiandentalacademy.com
  • 87. Self Etch Primer - studies  Rueggeberg et al (2000) - promt L-Pop w/o acid etch produce = bond strength as conventional bracket placement  Hitmi (2000)- no signi. diff b/w promt L-Pop & 37% phosphoric acid  Bergeron et al (2000)- resin enamel bond strength of diff self etching primer including promt L-Pop, was similar to or better than multistep www.indiandentalacademy.com
  • 88. Self Etch Primer - studies  Fritz et al(2001)- bonding with 3 self etching primer(Clearfil SE Bond,Clearfil Liner Bond 2V& Novabond)was = phos acid  Bishara et al(2001)- self etching primer prod a signi lower, but clinic acceptable, SBS compared to acid etch when Transbond XT composite used www.indiandentalacademy.com
  • 89. Self Etch Primer - studies  SHADOW ET AL (2002 JCO)  clinical eval. bond failure rates with a new self ething primer- Transbond Plus  Conclusion  Traditional AE 15 sec = etch & 15-20 sec = rinsing.10 sec= primer + curing  Transbond Plus =3 sec  Bracket retention > traditional www.indiandentalacademy.com
  • 90. Hydrophilic Primer ( MIP )  Bond failure – moisture contamination  Hormati et al – 50% decreased shear bond st  Hydrophilic primer ( HEMA & Maleic acid )dissolved in acetone – 3M Unitek. www.indiandentalacademy.com
  • 91. Hydrophilic Primer ( MIP ) S.J. Little Wood et al JO 2000  Compared the bond strength of bracket bonded with hydrophilic primer with conventional primer  Bond strength (6.43) was lower than conventional primer (8.71)  Bracket bonded with hydrophilic primer were 3.96 times more at risk of failure. www.indiandentalacademy.com
  • 92. Pre primed brackets  ADVANTAGES:  Consistent quality of adhesive  Reduced flash  Adequate bond strength  Less chances of contamination  Can be used in both direct & indirect tech.  Both metal & ceramic brackets are available www.indiandentalacademy.com
  • 93. Bonding Procedure  Cleaning  Enamel conditioning - Acid etching - Crystal growth - Sandblasting - Laser etching  Sealing  Bonding www.indiandentalacademy.com
  • 94. Bonding Procedure Four steps 1. Transfer 2. Positioning 3. Fitting 4. Removal of excess www.indiandentalacademy.com
  • 95. Bonding  TRANSFER  Adhesive put on bracket base  Bracket placed on the tooth closed to the correct position www.indiandentalacademy.com
  • 96. Bonding  POSITIONING  Proper vertical and horizontal positioning ( eg Using placement scaler with parallel edges) www.indiandentalacademy.com
  • 97. Bonding  FITTING  Bracket firmly pushed towards the tooth surface with one point contact www.indiandentalacademy.com
  • 98. Bonding REMOVAL OF EXCESS  Gingival irritation  Plaque build up  Better esthetics  Prevents staining and discoloration www.indiandentalacademy.com
  • 99. Bonding to Fluorosed teeth Dr.Veeresh  Bonding to the fluorosed teeth is difficult with conventional acid etching.  Aim – to evaluate the shear bond strength of the bracket to the fluorosed teeth by using a comb. of sandblasting & acid etching www.indiandentalacademy.com
  • 100. Bonding to Fluorosed teeth  Group 1 – acid etching  Group 2 – sandblasting  Group 3 - acid etching followed by sandblasting  Group 4 – sandblasting then acid etching Results  Only group 4 – Bond strength slightly higher than optimum (8.1Mpa) www.indiandentalacademy.com
  • 101. Curing Lights  Tungsten quartz halogen light  Argon laser  Xenon plasma arc light  Light emitting diode curing units ( LED )  Pulsed xenon plasma arc light www.indiandentalacademy.com
  • 102. Halogen Tungsten Quartz Curing Light  Bulb  quartz  Filament  Tungsten  Gas  Halogen Selective filters – blue light ( 400-500 micron)  40 seconds per bracket  15 minutes – both arches www.indiandentalacademy.com
  • 103. Halogen Tungsten Quartz Curing Light Disadvantages  Curing is time consuming  Light output < 1% of consumed electricity  Lifetime – 100hrs  High heat - degrades components of bulb www.indiandentalacademy.com
  • 104. 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 www.indiandentalacademy.com
  • 105. 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 www.indiandentalacademy.com
  • 106. Xenon plasma arc light  Introduced in late 1990’s  Short exposure time at lower cost  Curing time – 3-5 sec per bracket  Higher intensity than conventional  Expensive – argon laser > xenon plasma > conventional light.www.indiandentalacademy.com
  • 107. Comparison of efficiency of xenon plasma light and conventional 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 secs www.indiandentalacademy.com
  • 108. Light emitting diode curing units Mills –1995  Instead of hot filament – Halogen bulb.  LED – junction of doped semi conductors. www.indiandentalacademy.com
  • 109. 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 www.indiandentalacademy.com
  • 110. Light emitting diode curing units 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 www.indiandentalacademy.com
  • 111. Light emitting diode curing units  Disadvantages  Their technology is new to orthodontics, and the concept still is evolving.  Their curing time is slower than plasma arc curing lights and some enhanced halogen lights. www.indiandentalacademy.com
  • 112. Light emitting diode curing units  Disadvantages  Their batteries must be recharged.  They cost more than do conventional halogen lights.  They offer a relatively low intensity. www.indiandentalacademy.com
  • 113. 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 .  No diff in bond strength of orthodontic brackets bonded to teeth with conventional halogen light and LED curing units . www.indiandentalacademy.com
  • 114. Light Emitting Diode Units Dr.Ravitej  Aim - Shear Bond Strength Evaluation of three commercially Available Light Emitting Diode Units  The 3 different LED sources used in the study 1. Elipar Freelight (3M/ESPE) 2. Bee Cool (Confident dental equipments, Bangalore) 3. Apoza (Meghna and Co., Bangalore) www.indiandentalacademy.com
  • 115. 3 different LED sources used in the study 1. Elipar Freelight (3M/ESPE) 2. Bee Cool (Confident dental equipments, Bangalore) 3. Apoza (Meghna and Co., Bangalore) www.indiandentalacademy.com
  • 116.  Study sample -- 70 non-carious extracted upper premolar teeth  Divided into 7 groups of 10 each  Group I Group II-IV Group V-VII Elipar Freelight Bee Cool (Confident) Apoza Results Bond strength of G I and G IV samples fall in the optimal range. Bond strength values of other groups were suboptimal. www.indiandentalacademy.com
  • 117.  Group I sample (Elipar Freelight-10s, 3M/ESPE) can be considered most suitable  Group IV sample (Bee Cool-20s, Confident dental equipments, Bangalore) can also be considered appropriate www.indiandentalacademy.com
  • 118. References  Orthodontics current principles & techniques: Graber & Vanarsdall, 3rd Ed  Philip’s science of dental materials 11th Ed  Contemporary orthodontics: Proffit 3rd Ed  Orthodontic Materials Scientific & Clinical Aspects: William A. Brantley,Theodore Eliades  SEM Study & SBS measurement with 5% & 37% phosphoric acid - AJO-DO oct,1995 Wasundhara A. Bhad, Pushpa V. Hazarey, G.D.C.Nagpur www.indiandentalacademy.com
  • 119. References  Air abrasion tech vs conventional acid etching tech.- AJO-DO Jan 2000- Wandela L. et al  Laser etching of enamel for direct bonding- AO,1993 no.1- Von Fraunhofer et al  Clinical trials with crystal growth- AJO-DO Apr 1984 – Artun and Bergland  crystal growth on outer enamel surface- AJO-DO March 1986- Maijer & Smith  Thesis on Laser etching - Dr. Francis  Thesis on Bonding to Fluorosed teeth - Dr.Veeresh www.indiandentalacademy.com
  • 120. References  Bond strength with various etching times on young perm teeth- AJO-DO Jul 1991- Wang & Chau Lu  Effect of enamel etching time on bond strength & morphology- JCO Jan 1985- Wayne et al  Lab.& clinical evaluation of self etching primer JCO Jan 2001- Robert A. Miller  Variation in acid etch patterns with diff acids & etch time AJO-DO Jul 2001- Alastair Gardner et al www.indiandentalacademy.com
  • 121. References  Clinical evaluation of bond failure rates with a new self etching primer- JCO Dec 2002- Shadow Asgari et al  Rapid curing of bonding with xenon plasma arc light - AJO-DO Jun 2001- Oesterle, Sheldon, Newman et al  Evaluation of sealant in ortho bonding- AJO-DO Sep 1991- Wei Nan Wang  Bond strength comparison of MIP- AJO-DO Sep 2002- Shane & Timothy www.indiandentalacademy.com