Bonding and banding

Bonding andBonding and BandingBanding
www.indiandentalacademy.comwww.indiandentalacademy.com

Contents:Contents:
 IntroductionIntroduction
 Band or bondBand or bond
 AnatomyAnatomy
 BandingBanding
 Indications of bandingIndications of banding
 Steps in BandingSteps in Banding
 CementsCements
 Orthodontic bondingOrthodontic bonding
 History of bondingHistory of bonding
 Bracket bondingBracket bonding
 Advantages & disadvantagesAdvantages & disadvantages
 Classification of bonding materialsClassification of bonding materials
 Bonding procedureBonding procedure

Introduction:Introduction:
 Controlling the movement of a tooth in all directionsControlling the movement of a tooth in all directions
requires a firm attachment to that tooth.requires a firm attachment to that tooth.
 The orthodontic band, cemented to the tooth, is oneThe orthodontic band, cemented to the tooth, is one
practical means of obtaining such an attachment forpractical means of obtaining such an attachment for
most purposes. The continuing development andmost purposes. The continuing development and
refinement of materials and techniques for directionrefinement of materials and techniques for direction
cementation (bonding) of orthodontic attachments to thecementation (bonding) of orthodontic attachments to the
teeth offers a viable alternative to banding in manyteeth offers a viable alternative to banding in many
situations.situations.
 A vital secondary function of the orthodontic attachmentA vital secondary function of the orthodontic attachment
is protection of the tooth from carious attack.is protection of the tooth from carious attack.

 Any covering that provides a sheltered area, forAny covering that provides a sheltered area, for
accumulation on the surface of a tooth can encourageaccumulation on the surface of a tooth can encourage
plaque formation and increase the caries hazard, soplaque formation and increase the caries hazard, so
bands and bonding attachments must be carefullybands and bonding attachments must be carefully
designed, fitted, and cemented to control this problem.designed, fitted, and cemented to control this problem.
 Modern bands and bonding techniques have broughtModern bands and bonding techniques have brought
many improvements in the ease and comfort of themany improvements in the ease and comfort of the
placement, as well as in esthetics and protection of theplacement, as well as in esthetics and protection of the
tooth. These are not without new disadvantages of theirtooth. These are not without new disadvantages of their
own, but with a properly adapted technique the gains areown, but with a properly adapted technique the gains are
clear.clear.

Band or bondBand or bond
 There is no difference in the clinicalThere is no difference in the clinical
management of orthodontic therapy with bandedmanagement of orthodontic therapy with banded
or bonded attachments, provided that theor bonded attachments, provided that the
attachment slots are of the same dimensionsattachment slots are of the same dimensions
and bear the same relationship to theirand bear the same relationship to their
respective teeth.respective teeth.
 The choice between the two attachmentThe choice between the two attachment
methods involves four very differentmethods involves four very different
considerations: attachment options, separation,considerations: attachment options, separation,
tooth protection, and overall ease and efficiency.tooth protection, and overall ease and efficiency.

 Attachment optionsAttachment options
 The nature of a band, with its broad surface, places no limitationsThe nature of a band, with its broad surface, places no limitations
on the type or number of attachments that may be used. Weldingon the type or number of attachments that may be used. Welding
secures most attachments to bands, and soldering is alsosecures most attachments to bands, and soldering is also
available as an alternative means.available as an alternative means.
 Single attachments of small and medium size present no seriousSingle attachments of small and medium size present no serious
problems, but wide attachments are another matter.problems, but wide attachments are another matter.
 Bonding bases are not easily adapted to large areas, especially toBonding bases are not easily adapted to large areas, especially to
the sharply curved surfaces near the mesial and distal surfaces,the sharply curved surfaces near the mesial and distal surfaces,
so there is a tendency to avoid wide attachments for bonding.so there is a tendency to avoid wide attachments for bonding.
 Since lingual attachments are ordinarily used in combination withSince lingual attachments are ordinarily used in combination with
buccal attachments, they usually require multiple bondingbuccal attachments, they usually require multiple bonding
procedures.procedures.
 Bands facilitate such operations because any number ofBands facilitate such operations because any number of
attachments may be positioned with precision in an extraoralattachments may be positioned with precision in an extraoral
environment, followed by a single cementation procedure.environment, followed by a single cementation procedure.
 The two-stage operation required to bond both lingual and buccalThe two-stage operation required to bond both lingual and buccal
attachments to most teeth may be more an inconvenience thanattachments to most teeth may be more an inconvenience than
an actual limitation on options.an actual limitation on options.

 Interproximal space and arch lengthInterproximal space and arch length
 Bands occupy interproximal space and so add to archBands occupy interproximal space and so add to arch
length during the time that they are in place. This islength during the time that they are in place. This is
obviously recovered at the time that the bands areobviously recovered at the time that the bands are
removed, and in most but not all cases it presents littleremoved, and in most but not all cases it presents little
difficulty.difficulty.
 The spaces occupied by bands are typically closedThe spaces occupied by bands are typically closed
during the time that the dentition is also readaptingduring the time that the dentition is also readapting
after all of the other changes, and the process usuallyafter all of the other changes, and the process usually
continues uneventfully.continues uneventfully.
 Where arch length is extremely critical, the smallWhere arch length is extremely critical, the small
space occupied by bands can be very important.space occupied by bands can be very important.
 Bonding can provide a great advantage in such casesBonding can provide a great advantage in such cases
by not compounding the space problem with theby not compounding the space problem with the
interproximal width that would otherwise be added byinterproximal width that would otherwise be added by
bands.bands.

 Tooth protectionTooth protection
 Protection of the tooth is a collateral function of all means ofProtection of the tooth is a collateral function of all means of
securing orthodon-tic attachments to the teeth.securing orthodon-tic attachments to the teeth.
 A securely cemented band provides protection for the underlyingA securely cemented band provides protection for the underlying
tooth, with only the adjoining exposed areas subject to carioustooth, with only the adjoining exposed areas subject to carious
attack.attack.
 A damaged band with loss of cement seal can occasionallyA damaged band with loss of cement seal can occasionally
provide a sheltered area that will also be subject to decalcificationprovide a sheltered area that will also be subject to decalcification
or caries, but this is the exception.or caries, but this is the exception.
 On the positive side, interproximal areas are well protected by aOn the positive side, interproximal areas are well protected by a
cemented band, and caries in these areas is very rare in bandedcemented band, and caries in these areas is very rare in banded
teeth.teeth.
 Bonding adhesive can be extended into the gingival areas toBonding adhesive can be extended into the gingival areas to
protect those surfaces, but much larger areas are still leftprotect those surfaces, but much larger areas are still left
unprotected. These include the critical interproximal surfaces,unprotected. These include the critical interproximal surfaces,
where the caries process will tend to go on as usualwhere the caries process will tend to go on as usual
 Bonded attachments also expose the enamel to possible scarringBonded attachments also expose the enamel to possible scarring
in the removal of remaining adhesive after debonding heavilyin the removal of remaining adhesive after debonding heavily
filled, highly adherent bonding agents.filled, highly adherent bonding agents.

 Ease of placement and removalEase of placement and removal
 Bonding is better suited to mass application by theBonding is better suited to mass application by the
indirect technique, but this presents problems as well.indirect technique, but this presents problems as well.
Full efficiency with this technique requires routine use,Full efficiency with this technique requires routine use,
which can easily lead to full appliance placement inwhich can easily lead to full appliance placement in
cases where incremental placement would be morecases where incremental placement would be more
appropriate.appropriate.
 Individual attachments can be placed with comparableIndividual attachments can be placed with comparable
ease with either technique, with any advantage usuallyease with either technique, with any advantage usually
lying with banding.lying with banding.
 Removal is easiest for bands and the lightly filledRemoval is easiest for bands and the lightly filled
bonding materials that respond well to normal scalingbonding materials that respond well to normal scaling
technique.technique.
 Heavily filled adhesives may require abra-siveHeavily filled adhesives may require abra-sive
removal, which has attendant destructive potential.removal, which has attendant destructive potential.

Anatomy:Anatomy:
 Coronal anatomyCoronal anatomy
 Coronal anatomy can create problems for effectivelyCoronal anatomy can create problems for effectively
securing attachments by either banding or bonding.securing attachments by either banding or bonding.
 The upper anterior teeth present the most frequentThe upper anterior teeth present the most frequent
difficulty in band retention.difficulty in band retention.
 Certain tapers and contours of crown form offer little orCertain tapers and contours of crown form offer little or
no retention for bands, making a bonded attachmentno retention for bands, making a bonded attachment
much more effective.much more effective.
 Upper lateral- especially when these teeth areUpper lateral- especially when these teeth are
abnormally small. It is virtually impossible to contourabnormally small. It is virtually impossible to contour
attachments for bonding so that they will fit such a smallattachments for bonding so that they will fit such a small
-radius surface as closely as is necessary for secure-radius surface as closely as is necessary for secure
bonding.bonding.

 Cuspids can be attractive candidates forCuspids can be attractive candidates for
bonding when their crown form offers little or nobonding when their crown form offers little or no
band retention or dictates an excessivelyband retention or dictates an excessively
gingival attachment level.gingival attachment level.
 Sharply pointed cuspids can present anatomicalSharply pointed cuspids can present anatomical
constraints similar to those described for lateralconstraints similar to those described for lateral
incisors that compromise optimum position asincisors that compromise optimum position as
much with bonding as with banding.much with bonding as with banding.
 Buccal teeth generally offer good retention forBuccal teeth generally offer good retention for
bands, so coronal anatomy is seldom a reasonbands, so coronal anatomy is seldom a reason
for bonding.for bonding.
 Short crowns and round buccal surfaces canShort crowns and round buccal surfaces can
make bonding to bicuspids difficult, especiallymake bonding to bicuspids difficult, especially
when the wide brackets that give most effectivewhen the wide brackets that give most effective
control over tipping and rotations.control over tipping and rotations.

 Gingival anatomyGingival anatomy
 Most orthodontic patients are young, with many teethMost orthodontic patients are young, with many teeth
only recently erupted.only recently erupted.
 Gingival margins can be very high on such teeth,Gingival margins can be very high on such teeth,
especially the bicuspids, leaving clinical crowns often tooespecially the bicuspids, leaving clinical crowns often too
short for secure bonding.short for secure bonding.
 Bands can be much more effective than bonding in theseBands can be much more effective than bonding in these
cases.cases.
 The last molar may also have extremely high gingivalThe last molar may also have extremely high gingival
margins, or even a distal operculum, that can even makemargins, or even a distal operculum, that can even make
band placement a questionable procedure.band placement a questionable procedure.
 In extreme cases these teeth may need to be controlledIn extreme cases these teeth may need to be controlled
by removable appliances or extensions from anby removable appliances or extensions from an
appliance cemented to other teeth.appliance cemented to other teeth.

BandingBanding

 Despite the advent of bonded attachments, preformedDespite the advent of bonded attachments, preformed
stainless steel bands are still routinely utilized in fixedstainless steel bands are still routinely utilized in fixed
appliance therapy.appliance therapy.
 Banding offers superior reliability due to better resistanceBanding offers superior reliability due to better resistance
to occlusal interferences (Fricker, 1997).to occlusal interferences (Fricker, 1997).
 Band cements are necessary for band retention, eitherBand cements are necessary for band retention, either
by assisting mechanical retention or by true adhesion.by assisting mechanical retention or by true adhesion.
 They also serve to seal a band to a tooth, filling theThey also serve to seal a band to a tooth, filling the
irregular gaps to prevent stagnation areas.irregular gaps to prevent stagnation areas.
 Until the 1980s, the only practical way to place a fixedUntil the 1980s, the only practical way to place a fixed
attachment was to put it on a band that could beattachment was to put it on a band that could be
cemented to a tooth.cemented to a tooth.
 The pioneer orthodontists of the early 1900s used clampThe pioneer orthodontists of the early 1900s used clamp
bands, which were tightened around molar teeth bybands, which were tightened around molar teeth by
screw attachments.screw attachments.
 Preformed steel bands came into widespread use duringPreformed steel bands came into widespread use during
the 1960s, but are used now primarily for molar teeth.the 1960s, but are used now primarily for molar teeth.

Indications of banding:Indications of banding:
1.1. Teeth that will receive heavy intermittent forcesTeeth that will receive heavy intermittent forces
against the attachments, is the primary indication foragainst the attachments, is the primary indication for
banding.banding.

Example is an upper first molar against whichExample is an upper first molar against which
extraoral force will be placed via a head-gear. Theextraoral force will be placed via a head-gear. The
twisting and shearing forces often encounteredtwisting and shearing forces often encountered

Teeth that will need both labial and lingualTeeth that will need both labial and lingual
attachments, such as a molar with both headgearattachments, such as a molar with both headgear
and lingual arch tubes.and lingual arch tubes.
2.2. Isolated bonded lingual attachments that are notIsolated bonded lingual attachments that are not
tied to some other part of the appliance can betied to some other part of the appliance can be
swallowed or aspirated if something comes loose.swallowed or aspirated if something comes loose.

3.3. Teeth with short clinical crowns, so thatTeeth with short clinical crowns, so that
bonded brackets are difficult to placebonded brackets are difficult to place
correctly. If attached to a band, a tube orcorrectly. If attached to a band, a tube or
bracket can slightly displace the gingiva as itbracket can slightly displace the gingiva as it
is carried into proper position.is carried into proper position.

The decision to band rather than bondThe decision to band rather than bond
second premolars in adolescents is oftensecond premolars in adolescents is often
based on the length of the clinical crown.based on the length of the clinical crown.

 Band materialsBand materials
 To be easily formed into a band, a material must be softTo be easily formed into a band, a material must be soft
and ductile, like 24-carat gold.and ductile, like 24-carat gold.
 Such a material is easily deformed to adapt it to theSuch a material is easily deformed to adapt it to the
contours of the tooth, Edges of such a band can becontours of the tooth, Edges of such a band can be
burnished to a perfect fit at all the margins.burnished to a perfect fit at all the margins.
 In the mouth, under the many stresses of occlusion andIn the mouth, under the many stresses of occlusion and
accidental trauma band must be strong, stiff, and wellaccidental trauma band must be strong, stiff, and well
able to hold its shape.able to hold its shape.
 Castings can also be made to a beautiful fit, but betweenCastings can also be made to a beautiful fit, but between
the actual forming the band and its service in the mouththe actual forming the band and its service in the mouth
there is one more short but important operation: seatingthere is one more short but important operation: seating
of the band on the tooth.of the band on the tooth.
 This operation requires a material with properties-This operation requires a material with properties-
springy material that will stretch over the contours of thespringy material that will stretch over the contours of the
tooth and return to its original shape as the band istooth and return to its original shape as the band is
seated in its final position.seated in its final position.

 A band of soft material would distort in passing over theA band of soft material would distort in passing over the
wide parts of the tooth and overhang at the gingivalwide parts of the tooth and overhang at the gingival
margins.margins.
 If resistance is encountered in pushing a: band intoIf resistance is encountered in pushing a: band into
place, the edges may also crumple or tear.place, the edges may also crumple or tear.
 A springy material with optimum properties for bandA springy material with optimum properties for band
placement actually comes close to an optimumplacement actually comes close to an optimum
compromise between the extremely soft and hardcompromise between the extremely soft and hard
materialmaterial
 No metal has Sufficient elastic range to pass over theNo metal has Sufficient elastic range to pass over the
widest parts of all teeth and return to a good tight fit atwidest parts of all teeth and return to a good tight fit at
the gingival margin.the gingival margin.

 Thickness and hardnessThickness and hardness
 Manipulation during the manufacture of stainless steelManipulation during the manufacture of stainless steel
bands can produce varying degrees of work hardening,bands can produce varying degrees of work hardening,
which affects both adaptability and working life.which affects both adaptability and working life.
 Preformed seamless bands are usually manufactured byPreformed seamless bands are usually manufactured by
drawing a flat sheet into a shape, cutting off the top todrawing a flat sheet into a shape, cutting off the top to
leave a ring, forming that to band shape, and sometimesleave a ring, forming that to band shape, and sometimes
stretching to size.stretching to size.
 All of these operations work-harden the material,All of these operations work-harden the material,
requiring carefully controlled annealing during fabricationrequiring carefully controlled annealing during fabrication
to produce a band with sufficient softness for adaptabilityto produce a band with sufficient softness for adaptability
and durability.and durability.
 Softness is required for durability because anSoftness is required for durability because an
overhardened is also brittle and much more likely to splitoverhardened is also brittle and much more likely to split
or crack in service.or crack in service.

 Loosening of bandsLoosening of bands
 When a gold band has been subjected to occlusion orWhen a gold band has been subjected to occlusion or
other distorting forces, malleable metal is rapidlyother distorting forces, malleable metal is rapidly
pounded thin in the affected area.pounded thin in the affected area.
 The metal from thinning spot spreads in all directions,The metal from thinning spot spreads in all directions,
increasing the size of the band and breaking the cementincreasing the size of the band and breaking the cement
bond.bond.
 This can cause a local loosening of the band withoutThis can cause a local loosening of the band without
causing the entire band to become loose.causing the entire band to become loose.
 Detection of such loosening may be difficult, for the bandDetection of such loosening may be difficult, for the band
can still be tight when tested. If process continues, thecan still be tight when tested. If process continues, the
entire band will eventually loosen.entire band will eventually loosen.
 Because of the stiffness and toughness of stainlessBecause of the stiffness and toughness of stainless
steel, bands made of it tend to loosen in a differentsteel, bands made of it tend to loosen in a different
manner under the impact of occlusion.manner under the impact of occlusion.
 In a stainless steel band, the tendency is for the stiffIn a stainless steel band, the tendency is for the stiff
material to transmit the displacement over a larger areamaterial to transmit the displacement over a larger area
of the band, breaking the cement seal and loosening theof the band, breaking the cement seal and loosening the
entire band.entire band.

 Joining the metalJoining the metal ::
 Soldering or brazing is the practical method for joining gold alloys.Soldering or brazing is the practical method for joining gold alloys.
With gold materials, high-fusing, corrosion-resistant gold soldersWith gold materials, high-fusing, corrosion-resistant gold solders
may be used.may be used.
 These may be used with stainless steel only if the entire piece isThese may be used with stainless steel only if the entire piece is
heated to soldering temperature.heated to soldering temperature.
 When a large steel band is to be soldered, it is not always easy toWhen a large steel band is to be soldered, it is not always easy to
heat the entire piece, so low-fusing silver solder is generally used.heat the entire piece, so low-fusing silver solder is generally used.
 The bond between solder and stainless steel is a relatively weakThe bond between solder and stainless steel is a relatively weak
one, so joint design is an important consideration.one, so joint design is an important consideration.
 There should be mechanical locking effect, as when solder wrapsThere should be mechanical locking effect, as when solder wraps
around a wire.around a wire.
 On flat surfaces, such as attachments on bands, reinforcing withOn flat surfaces, such as attachments on bands, reinforcing with
several welds before soldering is very helpful.several welds before soldering is very helpful.
 Properly carried out, welding produces a neat, strong joint that isProperly carried out, welding produces a neat, strong joint that is
highly resistant to corrosion, For additional strength and rigidity,highly resistant to corrosion, For additional strength and rigidity,
such welded joints may be reinforced with silver solder.such welded joints may be reinforced with silver solder.
 This is a very effective means for attaching extruded molar tubes toThis is a very effective means for attaching extruded molar tubes to
bands.bands.

Steps in banding:Steps in banding:

Separation:Separation:
 Tight interproximal contacts make it impossible toTight interproximal contacts make it impossible to
properly seat a band, which means that some device toproperly seat a band, which means that some device to
separate the teeth usually must be used before banding.separate the teeth usually must be used before banding.
 The principle of seperators: a device to force or wedgeThe principle of seperators: a device to force or wedge
the teeth apart, is left in place long enough for initialthe teeth apart, is left in place long enough for initial
tooth movement to occur, so that the teeth are slightlytooth movement to occur, so that the teeth are slightly
separated by the appointment at which bands are to beseparated by the appointment at which bands are to be
fitted.fitted.
 Two main methods of separation are used for posteriorTwo main methods of separation are used for posterior
teeth:teeth:
(1) separating springs (2) elastomeric separators(1) separating springs (2) elastomeric separators
 Steel spring separators are easier to tolerate, both whenSteel spring separators are easier to tolerate, both when
they are being placed and removed, and as theythey are being placed and removed, and as they
separate the teeth. These separators tend to come looseseparate the teeth. These separators tend to come loose
and may fall out as they accomplish their purposeand may fall out as they accomplish their purpose

 Elastomeric separators are more difficult to insert, butElastomeric separators are more difficult to insert, but
are usually retained well when they are around theare usually retained well when they are around the
contact, and so may be left in position for somewhatcontact, and so may be left in position for somewhat
longer periods. Because elastomeric separators arelonger periods. Because elastomeric separators are
radiolucent, a serious problem can arise if one is lost intoradiolucent, a serious problem can arise if one is lost into
the interproximal space.the interproximal space.
 It is wise to use a brightly colored elastomeric material toIt is wise to use a brightly colored elastomeric material to
make a displaced separator more visible, and thesemake a displaced separator more visible, and these
separators should not be left in place for more than 2separators should not be left in place for more than 2
weeks.weeks.

Fitting bands:Fitting bands:
 Almost all bands are supplied now with preweldedAlmost all bands are supplied now with prewelded
attachments. This saves clinical time, and allows the useattachments. This saves clinical time, and allows the use
of templates to assure accurate placement of theof templates to assure accurate placement of the
attachment.attachment.
 Fitting a preformed band involves stretching the stainlessFitting a preformed band involves stretching the stainless
steel material over the tooth surface.steel material over the tooth surface.
 It follows that heavy force is needed to seat a preformedIt follows that heavy force is needed to seat a preformed
band. This force should be supplied by the masticatoryband. This force should be supplied by the masticatory
muscles of the patient, not by the arm strength of themuscles of the patient, not by the arm strength of the
dentist or dental assistant. Patients can bite harder anddentist or dental assistant. Patients can bite harder and
with much greater controlwith much greater control
 Preformed bands are designed to be fitted in a certainPreformed bands are designed to be fitted in a certain
sequence,sequence,

 A typical maxillary molar band is designed to be placedA typical maxillary molar band is designed to be placed
initially by hand pressure on the mesial and distalinitially by hand pressure on the mesial and distal
surfaces, The final seating is with heavy biting force onsurfaces, The final seating is with heavy biting force on
the distolingual corner.the distolingual corner.
 Lower molar bands are designed to be seated initiallyLower molar bands are designed to be seated initially
with hand pressure on the proximal surfaces, and thenwith hand pressure on the proximal surfaces, and then
with heavy biting force along the buccal but not thewith heavy biting force along the buccal but not the
lingual margins.lingual margins.
 Maxillary premolar bands are usually seated withMaxillary premolar bands are usually seated with
alternate pressure on the buccal and lingual surfaces,alternate pressure on the buccal and lingual surfaces,
 while mandibular premolar bands, like mandibularwhile mandibular premolar bands, like mandibular
molars, are designed for heavy pressure on the buccalmolars, are designed for heavy pressure on the buccal
surface only.surface only.

Cementation:Cementation:
 New cements specifically designed for orthodontic useNew cements specifically designed for orthodontic use
have supplanted the zinc phosphate and early glasshave supplanted the zinc phosphate and early glass
ionomer cements used in the 20th century.ionomer cements used in the 20th century.
 These tend to be a composite of glass ionomer andThese tend to be a composite of glass ionomer and
resin materials, and usually are light cured.resin materials, and usually are light cured.
 Their use has greatly reduced problems with leakageTheir use has greatly reduced problems with leakage
beneath the bands that previously was a risk forbeneath the bands that previously was a risk for
decalcification of banded teethdecalcification of banded teeth
 All interior surfaces of an orthodontic band must beAll interior surfaces of an orthodontic band must be
coated with cement before it is placed, so that there is nocoated with cement before it is placed, so that there is no
base metal.base metal.
 As the band is carried to place, the occlusal surfaceAs the band is carried to place, the occlusal surface
should be covered so that cement is expressed from theshould be covered so that cement is expressed from the
gingival as well as the occlusal margins of the band.gingival as well as the occlusal margins of the band.

Cements:Cements:
 Zinc phosphate cementZinc phosphate cement
 Widely used for band cementation for much of the lastWidely used for band cementation for much of the last
century. It has high compressive strength, but sufferscentury. It has high compressive strength, but suffers
from low tensile strength and high solubility, resulting infrom low tensile strength and high solubility, resulting in
microleakage and demineralisation.microleakage and demineralisation.
 Zinc polycarboxylate cementZinc polycarboxylate cement
 were introduced to orthodontics in the early 1970s andwere introduced to orthodontics in the early 1970s and
offered the advantage of chemical adherence to enamel.offered the advantage of chemical adherence to enamel.
 physical and handling properties were flawed, due tophysical and handling properties were flawed, due to
poor tensile bond strength, solubility, viscosity, and shortpoor tensile bond strength, solubility, viscosity, and short
working time.working time.
 Both zinc phosphate and polycarboxylate cements haveBoth zinc phosphate and polycarboxylate cements have
been superceded by new generations of adhesivebeen superceded by new generations of adhesive
cements, and are now largely obsolete as bandingcements, and are now largely obsolete as banding
cementscements

 Glass ionomer cementsGlass ionomer cements
 Were introduced by Wilson and Kent in 1972 asWere introduced by Wilson and Kent in 1972 as
restorative materials, and subsequently becamerestorative materials, and subsequently became
available as luting cements.available as luting cements.
 GICs offered considerable advantages in physicalGICs offered considerable advantages in physical
properties over previous banding cements.properties over previous banding cements.
 GICs capacity for adhesion to enamel and metal,GICs capacity for adhesion to enamel and metal,
combined with higher compressive and tensile strengthscombined with higher compressive and tensile strengths
(Durning(Durning et alet al., 1994), provides superior clinical., 1994), provides superior clinical
performance due to reduced band failure (Fricker andperformance due to reduced band failure (Fricker and
McLachlon, 1985, 1987; Mizrahi, 1988; Stirrups, 1991).McLachlon, 1985, 1987; Mizrahi, 1988; Stirrups, 1991).
 Also there is better protection from microleakage sinceAlso there is better protection from microleakage since
bond failure usually occurs at the cement band interfacebond failure usually occurs at the cement band interface
(Millet(Millet et alet al., 1998) and the solubility is low.., 1998) and the solubility is low.
 GICs leach fluoride over prolonged periods, thusGICs leach fluoride over prolonged periods, thus
reducing the potential for demineralization.reducing the potential for demineralization.

Zinc phosphate cement:Zinc phosphate cement:
 COMPOSITIONCOMPOSITION
 PowderPowder
1.1. Zinc oxide (ZnO) 90.2%Zinc oxide (ZnO) 90.2%
2.2. Magnesium oxide (MgO) 8.2 % (decrease temperature ofMagnesium oxide (MgO) 8.2 % (decrease temperature of
calcinations process)calcinations process)
3.3. Silicon dioxide (SiO2) 1.4 (inactive filler)Silicon dioxide (SiO2) 1.4 (inactive filler)
1.1. Bismuth trioxide (Bi2O3) 0.1 (smoothness of freshlyBismuth trioxide (Bi2O3) 0.1 (smoothness of freshly
mix cement in highmix cement in high
concentration it may lengthenconcentration it may lengthen
the setting time)the setting time)
Miscellaneous (BaO, Ba2So4, CaO) 0.1Miscellaneous (BaO, Ba2So4, CaO) 0.1
 LiquidLiquid
1.1. Phosphoric acid 38.2Phosphoric acid 38.2
2.2. aluminum phosphate or zinc phosphate) 16.2aluminum phosphate or zinc phosphate) 16.2
3.3. Aluminum (Al) 2.5Aluminum (Al) 2.5www.indiandentalacademy.comwww.indiandentalacademy.com

 CHARACTERISTICS PROPERTIESCHARACTERISTICS PROPERTIES
 Physical and biologic propertiesPhysical and biologic properties
 Two physical properties of the cement that are relevant to theTwo physical properties of the cement that are relevant to the
retention, they are the mechanical properties and the solubility’s.retention, they are the mechanical properties and the solubility’s.
 The resoration can get dislodged if the underlying cement isThe resoration can get dislodged if the underlying cement is
stressed beyond its strength.stressed beyond its strength.
 High solubility can induce loss of the cement needed for theHigh solubility can induce loss of the cement needed for the
retention and may create plaque retention sites.retention and may create plaque retention sites.
 compressive strength of 104MPacompressive strength of 104MPa
 tensile strength of 5.5 MPa.tensile strength of 5.5 MPa.
 modulus of elasticity of approximately 13 GPa. Thus it is quite stiffmodulus of elasticity of approximately 13 GPa. Thus it is quite stiff
and should be resistant to elastic deformation even when it isand should be resistant to elastic deformation even when it is
employed for cementation of band that are subjected to highemployed for cementation of band that are subjected to high
masticatory stress.masticatory stress.
 A reduction in the powder liquid ratio of the mix produces aA reduction in the powder liquid ratio of the mix produces a
markedly weaker cement.markedly weaker cement.
 A loss or gain in the water content of the liquid reduces theA loss or gain in the water content of the liquid reduces the
compressive and tensile strengths of the cement.compressive and tensile strengths of the cement.

 RetentionRetention
 Setting of the zinc phosphate cement doesn’t involve anySetting of the zinc phosphate cement doesn’t involve any
reaction with surrounding hard tissue or other restorativereaction with surrounding hard tissue or other restorative
materials. Therefore primary bonding occur bymaterials. Therefore primary bonding occur by
mechanical interlocking and not by chemical interaction.mechanical interlocking and not by chemical interaction.
 Solubility and disintegrationSolubility and disintegration
 The premature contact of the incompletely set cementThe premature contact of the incompletely set cement
with water results in dissolution and leaching of thatwith water results in dissolution and leaching of that
surface.surface.
 Wear abrasion and attack of food decompositionWear abrasion and attack of food decomposition
products accelerate the disintegration of zinc phosphateproducts accelerate the disintegration of zinc phosphate
cements.cements.
 Greater resistance to disintegration is achieved byGreater resistance to disintegration is achieved by
increasing the powder liquid ratio.increasing the powder liquid ratio.
 A thicker mix of cement exhibits less solubility than aA thicker mix of cement exhibits less solubility than a
thinner mix.thinner mix.

 Dimensional stabilityDimensional stability
 Zinc phosphate cement exhibits shrinkage on hardening.Zinc phosphate cement exhibits shrinkage on hardening.
 Shrinkage is on the order of 0.04% to 0.06% in 7 days.Shrinkage is on the order of 0.04% to 0.06% in 7 days.
 AcidityAcidity
 During the formation of zinc phosphate cement, the union of zincDuring the formation of zinc phosphate cement, the union of zinc
oxide powder with phosphoric acid liquid is accompanied by aoxide powder with phosphoric acid liquid is accompanied by a
change in pH.change in pH.
 In the early stages the pH increases rapidly, with a standard mixIn the early stages the pH increases rapidly, with a standard mix
reaching the pH of 4.2 within 3 minutesreaching the pH of 4.2 within 3 minutes
 At the end of one hour this value increases to about 6 and is nearlyAt the end of one hour this value increases to about 6 and is nearly
neutral at 48 hours.neutral at 48 hours.
 Investigations have shown that the initial acidity of zinc phosphateInvestigations have shown that the initial acidity of zinc phosphate
cement at the time of placement into the tooth may excite pulpalcement at the time of placement into the tooth may excite pulpal
response.response.
 Thermal and electrical conductivityThermal and electrical conductivity
 One of the primary uses of zinc phosphate cement is an insulatingOne of the primary uses of zinc phosphate cement is an insulating
base under metallic restorations.base under metallic restorations.

 APPLICATIONSAPPLICATIONS
 Zinc phosphate cement is used most commonly for lutingZinc phosphate cement is used most commonly for luting
permanent metal restorations and as a base.permanent metal restorations and as a base.
 Other applications include cementation of orthodontic bands and theOther applications include cementation of orthodontic bands and the
use of cement as a provisional restoration.use of cement as a provisional restoration.
 ADVANTAGESADVANTAGES
 Adequate strength to maintain the restorationAdequate strength to maintain the restoration
 Relatively good manufacturer propertiesRelatively good manufacturer properties
 Mixed easily and that they set sharply to a relatively strong massMixed easily and that they set sharply to a relatively strong mass
from a fluid consistency.from a fluid consistency.
 DISADVANTAGESDISADVANTAGES
 Irritating effect on the pulpIrritating effect on the pulp
 Lack of anticariogenic propertiesLack of anticariogenic properties
 Lack of adhesion to the toothLack of adhesion to the tooth
 Vulnerability to acid attackVulnerability to acid attack
 BrittlenessBrittleness
 Solubility in acid fluids.Solubility in acid fluids.

Zinc polycarboxylate cement:Zinc polycarboxylate cement:
 PowderPowder
 zinc oxide (basic ingredient)zinc oxide (basic ingredient)
 magnesium oxide (reduce the reactivity of zinc oxide).magnesium oxide (reduce the reactivity of zinc oxide).
 Stannic acid (may be substituted for magnesium oxide).Stannic acid (may be substituted for magnesium oxide).
 Other oxides such as bismuth and aluminumOther oxides such as bismuth and aluminum
 stannous fluoride, (which modify setting time and imparts antistannous fluoride, (which modify setting time and imparts anti
cariogenic properties)cariogenic properties)
 LiquidLiquid
 The liquid is a water solution of polyacrylic acid.The liquid is a water solution of polyacrylic acid.
 32% to 42% solution of polyacrylic acid32% to 42% solution of polyacrylic acid
 copolymer of acrylic acid, Itaconic and tartaric may be present tocopolymer of acrylic acid, Itaconic and tartaric may be present to
stabilize the liquid, which can gel on extended storage.stabilize the liquid, which can gel on extended storage.

 Surface penetration and retentionSurface penetration and retention
 Despite the adhesion of the cement to tooth structure,Despite the adhesion of the cement to tooth structure,
polycarboxylate cements are not superior to zinc phosphate cementpolycarboxylate cements are not superior to zinc phosphate cement
in the retention of cast noble metal restorations.in the retention of cast noble metal restorations.
 Examination of fractured surfaces shows that failure usually occursExamination of fractured surfaces shows that failure usually occurs
at the cement –tooth interface with zinc phosphate cement.at the cement –tooth interface with zinc phosphate cement.
 In the case of polycarboxylate cements, the failure occurs usually atIn the case of polycarboxylate cements, the failure occurs usually at
the cement metal interface.the cement metal interface.
 The cement does not bond to the metal in the chemicallyThe cement does not bond to the metal in the chemically
contaminated condition.contaminated condition.
 Thus it is essential that this contaminated surface on the casting beThus it is essential that this contaminated surface on the casting be
removed to improve wetability and the mechanical bond at theremoved to improve wetability and the mechanical bond at the
cement metal interface.cement metal interface.
 The surface can be carefully abraded with a small stone, or it can beThe surface can be carefully abraded with a small stone, or it can be
sandblasted with high pressure air and alumina abrasives.sandblasted with high pressure air and alumina abrasives.

 Removal of excess cementRemoval of excess cement
 During setting the polycarboxylate cement passesDuring setting the polycarboxylate cement passes
through a rubbery stage that makes the removal of thethrough a rubbery stage that makes the removal of the
excess cement quite difficult.excess cement quite difficult.
 The excess cement that has extruded beyond theThe excess cement that has extruded beyond the
margins of the casting should not be removed while themargins of the casting should not be removed while the
cement is in this stage, because some of the cementcement is in this stage, because some of the cement
may be pulled out from beneath the margins leaving amay be pulled out from beneath the margins leaving a
void.void.
 The excess should be removed when the cementThe excess should be removed when the cement
becomes hard.becomes hard.
 The outer surface should be coated with a separatingThe outer surface should be coated with a separating
medium like petroleum jelly, to prevent excess frommedium like petroleum jelly, to prevent excess from
adhering.adhering.
 Another approach is to start removing excess cement asAnother approach is to start removing excess cement as
soon as seating is completed.soon as seating is completed.

 Mechanical propertiesMechanical properties
 The compressive strength of polycarboxylate cement isThe compressive strength of polycarboxylate cement is
55 Mpa.55 Mpa.
 The tensile strength is slightly higher than that of zincThe tensile strength is slightly higher than that of zinc
phosphate cement. 6.2 MPaphosphate cement. 6.2 MPa
 Zinc polycarboxylate cement is not as brittle as zincZinc polycarboxylate cement is not as brittle as zinc
phosphate cement.phosphate cement.
 SolubilitySolubility
 The solubility of the cement in water is low, but when it isThe solubility of the cement in water is low, but when it is
exposed to organic acids with a pH of 4.5 or less, theexposed to organic acids with a pH of 4.5 or less, the
solubility markedly increases.solubility markedly increases.
 Also a reduction in the powder liquid ratio results inAlso a reduction in the powder liquid ratio results in
significantly higher solubility and disintegration rate in thesignificantly higher solubility and disintegration rate in the
oral cavity.oral cavity.

 Bond strengthBond strength
 An interesting feature of polycarboxylate cement is its bonding toAn interesting feature of polycarboxylate cement is its bonding to
enamel and dentin, which is attributed to the ability of theenamel and dentin, which is attributed to the ability of the
carboxylate groups in the polymer molecule to chelate to calcium.carboxylate groups in the polymer molecule to chelate to calcium.
 The bond strength to enamel has been reported to be from 3.4 to 13The bond strength to enamel has been reported to be from 3.4 to 13
MPa and to that of dentin is 2.07 MPa.MPa and to that of dentin is 2.07 MPa.
 Dimensional stabilityDimensional stability
 The zinc polycarboxylate cement shows a linear contraction whenThe zinc polycarboxylate cement shows a linear contraction when
setting at 37 C. the amount of contraction varies from 1 % for a wetsetting at 37 C. the amount of contraction varies from 1 % for a wet
specimen at 1 day to 6 % for a dry specimen at 14 days.specimen at 1 day to 6 % for a dry specimen at 14 days.
 AcidityAcidity
 Zinc polyacarboxylate cements are slightly more acidic than zincZinc polyacarboxylate cements are slightly more acidic than zinc
phosphate cements when first mixed, but the acid is only weaklyphosphate cements when first mixed, but the acid is only weakly
dissociated, and penetration of the highly molecular weight polymerdissociated, and penetration of the highly molecular weight polymer
molecules toward pulpal tissue is minimal.molecules toward pulpal tissue is minimal.

 Zinc polycarboxylate cements are used primarily for lutingZinc polycarboxylate cements are used primarily for luting
permanent alloy restorations and as bases. Theses cements havepermanent alloy restorations and as bases. Theses cements have
also been used in orthodontics for cementation of bands.also been used in orthodontics for cementation of bands.
 ADVANTAGESADVANTAGES
 Biocompatibility with the pulp is excellent.Biocompatibility with the pulp is excellent.
 Postoperative sensitivity is negligible when used as a luting agentPostoperative sensitivity is negligible when used as a luting agent
 Adhesion to tooth and alloyAdhesion to tooth and alloy
 Easy manipulation.Easy manipulation.
 DISADVANTAGESDISADVANTAGES
 Need for accurate proportioning required for optimal propertiesNeed for accurate proportioning required for optimal properties
 Greater viscoelasticityGreater viscoelasticity
 Shorter working timeShorter working time
 Low compressive strengthLow compressive strength

Glass ionomer cement:Glass ionomer cement:
 Glass ionomer is the generic name of a group ofGlass ionomer is the generic name of a group of
materials that use silicate glass powder and an aqueousmaterials that use silicate glass powder and an aqueous
solution of polyacrylic acid.solution of polyacrylic acid.
 The material acquires its name from its formulation of aThe material acquires its name from its formulation of a
glass powder and an ionomeric acid that containsglass powder and an ionomeric acid that contains
carboxyl groups. It is also referred to as polyalkeonatecarboxyl groups. It is also referred to as polyalkeonate
cement.cement.
 Originally, the cement was designed for the estheticOriginally, the cement was designed for the esthetic
restoration of anterior teeth and it was recommended forrestoration of anterior teeth and it was recommended for
use in restoring teeth with class III and V cavityuse in restoring teeth with class III and V cavity
preparations. Also because the cement produces a trulypreparations. Also because the cement produces a truly
adhesive bond to tooth structure.adhesive bond to tooth structure.
 The use of GIC has broadened to encompassThe use of GIC has broadened to encompass
formulations as luting agents, liners, restorativeformulations as luting agents, liners, restorative
materials, core buildups and pit and fissure sealants.materials, core buildups and pit and fissure sealants.www.indiandentalacademy.comwww.indiandentalacademy.com

 TYPES OF GLASS IONOMER CEMENTTYPES OF GLASS IONOMER CEMENT
 There are three types based on their formulations and their potentialThere are three types based on their formulations and their potential
usesuses
 Type IType I
 Luting applicationsLuting applications
 Powder liquid ratio is generally 1.5 : 1Powder liquid ratio is generally 1.5 : 1
 Grain size 15 microns or lessGrain size 15 microns or less
 High early resistance to water contaminationHigh early resistance to water contamination
 Radiopaque for easy detection of excessRadiopaque for easy detection of excess
 Limited extension of working time through chilling glass slab.Limited extension of working time through chilling glass slab.
 Type IIType II
 Restorative materialRestorative material
 Powder liquid ratio 3:1Powder liquid ratio 3:1
 Must protect for 24 hours for best resultsMust protect for 24 hours for best results
 Reduced fluoride content to improve translucencyReduced fluoride content to improve translucency

 Type IIIType III
 Liners and bases.Liners and bases.
 Powder liquid ratio varies according to usePowder liquid ratio varies according to use
 Lining requires 1.5:1 for easyLining requires 1.5:1 for easy
 Base requires 3:1 or greater for strengthBase requires 3:1 or greater for strength
 Light activated varieties availableLight activated varieties available
 Type IVType IV
 Metal modified glass ionomer cementMetal modified glass ionomer cement
 Miracle mixMiracle mix
 Cermet cementCermet cement
 Light curable versions of GIC are also available. (HEMA added toLight curable versions of GIC are also available. (HEMA added to
liquid)liquid)
 Hybrid glass ionomer resin modifiedHybrid glass ionomer resin modified

 powder is an acid soluble calcium fluroaluminosilicate glass.powder is an acid soluble calcium fluroaluminosilicate glass.
 Lanthanum, strontium, barium or zinc oxide additions provideLanthanum, strontium, barium or zinc oxide additions provide
radiopacity.radiopacity.
 SiO2 29.0SiO2 29.0
 Al2O3 16.6Al2O3 16.6
 AlF3 5.3AlF3 5.3
 CaF2 34.3CaF2 34.3
 AlPO4 3.8AlPO4 3.8
 NaF 9.3NaF 9.3
 Liquid
 aqueous solutions of polyacrylic acid in a concentration of about 50
%.
• The acid is form of a copolymer with itaconic, maleic, or tricaboxylic
acid. Theses acids tend to increase the reactivity of the liquid,
decreases the viscosity, and reduce the tendency for gelation.
• Tartaric acid present in the liquid improves the handling
characteristics and increases the working time however it shortens
the setting time. www.indiandentalacademy.comwww.indiandentalacademy.com

 ROLE OF FLUORIDEROLE OF FLUORIDE
 Glass ionomer cements are bioactive. They formGlass ionomer cements are bioactive. They form
permanent adhesive bonds to dentin and enamel, hencepermanent adhesive bonds to dentin and enamel, hence
preventing the development of secondary caries.preventing the development of secondary caries.
 They also release fluoride over a prolonged period andThey also release fluoride over a prolonged period and
so can arrest the progress of caries.so can arrest the progress of caries.
 Of all dental cements they are the most resistant toOf all dental cements they are the most resistant to
erosion in the acidic stagnation regions of the mouth.erosion in the acidic stagnation regions of the mouth.

 StrengthStrength
 The 24-hour compressive strength of Glass ionomer cementsThe 24-hour compressive strength of Glass ionomer cements
ranges from 90 to 230 MPa and is greater than that of zincranges from 90 to 230 MPa and is greater than that of zinc
phosphate cement.phosphate cement.
 Tensile strength is similar to those of zinc phosphate cement.Tensile strength is similar to those of zinc phosphate cement.
 The elastic modulus of glass ionomer cements is less than that ofThe elastic modulus of glass ionomer cements is less than that of
zinc phosphate but more than that of zinc polycarboxylate cement.zinc phosphate but more than that of zinc polycarboxylate cement.
 Bond strengthBond strength
 Glass ionomer cements bond to dentin with values of tensile bondGlass ionomer cements bond to dentin with values of tensile bond
strength reported between 1 and 3 MPa.strength reported between 1 and 3 MPa.
 The bond strength has been improved by treating the dentin with anThe bond strength has been improved by treating the dentin with an
acidic conditioner followed by an application of a dilute aqueousacidic conditioner followed by an application of a dilute aqueous
solution of ferric chloride.solution of ferric chloride.
 Glass ionomer cements bond well to enamel, stainless steel, and tinGlass ionomer cements bond well to enamel, stainless steel, and tin
oxide plated platinum and goldoxide plated platinum and gold

 SolubilitySolubility
 The solubility in water for the first 24 hours is highThe solubility in water for the first 24 hours is high
 After the cement has been allowed to mature fully, itAfter the cement has been allowed to mature fully, it
becomes one of the most resistant of the nonresinbecomes one of the most resistant of the nonresin
cements to solubility and disintegration in the oral cavity.cements to solubility and disintegration in the oral cavity.
 Biologic propertiesBiologic properties
 Biological evaluations of glass jonomer cements haveBiological evaluations of glass jonomer cements have
been done by tissue culture and animal tests. Thebeen done by tissue culture and animal tests. The
culture cells showed a weaker reaction to glass ionomerculture cells showed a weaker reaction to glass ionomer
cement than to ZOE or zinc polycarboxylate cements.cement than to ZOE or zinc polycarboxylate cements.
 Pulp tissue reactions showed no difference betweenPulp tissue reactions showed no difference between
glass ionomer and ZOE cements. These reactions haveglass ionomer and ZOE cements. These reactions have
been described as mild.been described as mild.
 Glass ionomer luting cements may cause prolongedGlass ionomer luting cements may cause prolonged
hypersensitivity, varying from mild to severe.hypersensitivity, varying from mild to severe.

 Microleakage has been suggested as an explanation, butMicroleakage has been suggested as an explanation, but
a recent study showed no increase in bacterial counts 56a recent study showed no increase in bacterial counts 56
days after cementation of crowns with a glass ionomerdays after cementation of crowns with a glass ionomer
cement. These cements may be bacteriostatic orcement. These cements may be bacteriostatic or
bactericidal, however, because of fluoride release.bactericidal, however, because of fluoride release.
 Glass ionomer cements are primarily used forGlass ionomer cements are primarily used for
permanent cement, as a base, and as a class V fillingpermanent cement, as a base, and as a class V filling
material.material.
 The cement has been evaluated as a pit and fissureThe cement has been evaluated as a pit and fissure
sealant and an endodontic sealer.sealant and an endodontic sealer.
 Glass ionomer cements are being used clinically forGlass ionomer cements are being used clinically for
cementation of orthodontic bands because of their abilitycementation of orthodontic bands because of their ability
to minimize decalcification of enamel by means ofto minimize decalcification of enamel by means of
fluoride release.fluoride release.

 Resin-modified Glass Ionomer CementResin-modified Glass Ionomer Cement
 Traditional GICs were modified by the incorporation ofTraditional GICs were modified by the incorporation of
resin, and water-soluble initiators and activators, toresin, and water-soluble initiators and activators, to
produce dual cure hybrid cements.produce dual cure hybrid cements.
 These set partly via an acid-base reaction and partlyThese set partly via an acid-base reaction and partly
through a polymerisation reaction (Bourkethrough a polymerisation reaction (Bourke et alet al., 1992).., 1992).
 The advantages they offer are in improved handlingThe advantages they offer are in improved handling
characteristics, due to command setting, longer workingcharacteristics, due to command setting, longer working
time, and greater tolerance of moisture.time, and greater tolerance of moisture.
 The bond strength of modified GICs is reported asThe bond strength of modified GICs is reported as
superior to traditional GICs (Mennemeyersuperior to traditional GICs (Mennemeyer et alet al., 1999),., 1999),
although no significant difference in failure rates wasalthough no significant difference in failure rates was
found in a clinical studyfound in a clinical study ..

 Acid-modified Composite Resin CementAcid-modified Composite Resin Cement
 These compomer or composite cements are composedThese compomer or composite cements are composed
of ion-leachable glass in a polymeric matrix.of ion-leachable glass in a polymeric matrix.
 They set by a light-cured resin reaction, not an acid-baseThey set by a light-cured resin reaction, not an acid-base
reaction, and rely upon water diffusion into the setreaction, and rely upon water diffusion into the set
polymer to allow fluoride release. The set material canpolymer to allow fluoride release. The set material can
take up and release topical fluoride.take up and release topical fluoride.
 These cements are produced both as dual pasteThese cements are produced both as dual paste
systems, which are dual cure, and as single pastesystems, which are dual cure, and as single paste
systems, which are light cured.systems, which are light cured.
 Their handling characteristics are generally very good,Their handling characteristics are generally very good,
with minimal mixing and command setting, but thewith minimal mixing and command setting, but the
material can be difficult to place in the bands.material can be difficult to place in the bands.
 These cements do not adhere chemically like GICs sinceThese cements do not adhere chemically like GICs since
they do not contain any polyacid, but the adhesion is,they do not contain any polyacid, but the adhesion is,
instead, a resin type.instead, a resin type.

 Comparative laboratory investigations found that anComparative laboratory investigations found that an
acid-modified composite resin cement had significantlyacid-modified composite resin cement had significantly
higher tensile strength and significantly lower probabilityhigher tensile strength and significantly lower probability
of band failure than a traditional GIC (Mennemeyerof band failure than a traditional GIC (Mennemeyer et alet al.,.,
1999; Millet1999; Millet et alet al., 1998).., 1998).
 A clinical trial found no significant difference in failureA clinical trial found no significant difference in failure
rates between a traditional GIC, a resin-modified GICrates between a traditional GIC, a resin-modified GIC
and an acid-modified resin cement. In contrast to GICs,and an acid-modified resin cement. In contrast to GICs,
these cements tend to fail at the cement/ enamelthese cements tend to fail at the cement/ enamel
interface, and there is consequently greater risk ofinterface, and there is consequently greater risk of
stagnation areas, micro-leakage, and demineralizationstagnation areas, micro-leakage, and demineralization
(Fricker, 1997).(Fricker, 1997).

Bonding:Bonding:
 BONDINGBONDING – In dentistry “bonding” refers to– In dentistry “bonding” refers to
attachment of fluid bonding resins to enamelattachment of fluid bonding resins to enamel
surfaces.surfaces.
 Bonding = Attachment +AdhesionBonding = Attachment +Adhesion
 Attachment is the mechanical interlockingAttachment is the mechanical interlocking
established with acid etching technique.established with acid etching technique.
 Adhesion is the force or inter molecularAdhesion is the force or inter molecular
attraction that exits between two un likeattraction that exits between two un like
substances when placed in intimate contact withsubstances when placed in intimate contact with
each other.each other.

Orthodontic bonding:Orthodontic bonding:
 It is the process which involves the joining of twoIt is the process which involves the joining of two
adherents by an intervening layer of bondingadherents by an intervening layer of bonding
agent.agent.
 Achieving a low bond failure rate should be aAchieving a low bond failure rate should be a
high-priority objective, since replacing loosehigh-priority objective, since replacing loose
brackets is inefficient, time-consuming, andbrackets is inefficient, time-consuming, and
costly.costly.
 Most bond failures result from inconsistencies inMost bond failures result from inconsistencies in
the bonding technique and not because of thethe bonding technique and not because of the
bonding resins, inadequate bond strengths, orbonding resins, inadequate bond strengths, or
quality of the brackets being used.quality of the brackets being used.

 The Basis of BondingThe Basis of Bonding
 Bonding of attachments, eliminating the need forBonding of attachments, eliminating the need for
bands, was a dream for many years beforebands, was a dream for many years before
rather abruptly becoming a routine clinicalrather abruptly becoming a routine clinical
procedure in the 1980s.procedure in the 1980s.
 Bonding is based on the mechanical locking ofBonding is based on the mechanical locking of
an adhesive to irregularities in the enamelan adhesive to irregularities in the enamel
surface of the tooth and to mechanical lockssurface of the tooth and to mechanical locks
formed in the base of the orthodonticformed in the base of the orthodontic

 Diagrammatic representation of the effect of theDiagrammatic representation of the effect of the
preparation of the enamel surface before bonding.preparation of the enamel surface before bonding.
Pretreatment with phosphoric acid creates minutePretreatment with phosphoric acid creates minute
irregularities in the enamel surface allowing the bondingirregularities in the enamel surface allowing the bonding
material to form penetrating “tags” that mechanicallymaterial to form penetrating “tags” that mechanically
interlock with the bonding surfaceinterlock with the bonding surface

History of bonding:History of bonding:
 Increased adhesion by acid pretreatment, using 85%Increased adhesion by acid pretreatment, using 85%
phosphoric acid, was demonstrated in 1955 byphosphoric acid, was demonstrated in 1955 by
BUONOCORE.BUONOCORE.
 SADLER in 1958 attempted to cement orthodonticSADLER in 1958 attempted to cement orthodontic
attachment directly to enamel.attachment directly to enamel.
 NEWMAN in 1965 applied Buonocores findings to directNEWMAN in 1965 applied Buonocores findings to direct
bonding of orthodontic attachments to tooth surface,bonding of orthodontic attachments to tooth surface,
used Epoxy resin (diglycidyl ether of Bisphenol A with aused Epoxy resin (diglycidyl ether of Bisphenol A with a
polyamide curing agent, used 40% phosphoric acid forpolyamide curing agent, used 40% phosphoric acid for
60 sec. This was the start of so called direct bonding60 sec. This was the start of so called direct bonding
method.method.
 MITCHELL in 1967 used black copper cement and goldMITCHELL in 1967 used black copper cement and gold
direct attachments.direct attachments.
 MIZRAHI AND SMITH in 1969 used Zinc polyacrylateMIZRAHI AND SMITH in 1969 used Zinc polyacrylate
cement for direct bonding.cement for direct bonding.

 Around 1970’s several articles appeared on bondingAround 1970’s several articles appeared on bonding
attachments with different adhesivesattachments with different adhesives
 MIURA ET AL described an acrylic resin (orthombite),MIURA ET AL described an acrylic resin (orthombite),
using a modified trialkyl borane catalyst, that proved tousing a modified trialkyl borane catalyst, that proved to
be particularly successful for bonding plastic bracketsbe particularly successful for bonding plastic brackets
and for enhanced adhesion in the presence of moisture.and for enhanced adhesion in the presence of moisture.
 RETIEF, DREYET GAVRON in 1970 used epoxy resin.RETIEF, DREYET GAVRON in 1970 used epoxy resin.
curing time required was 30 minutes.curing time required was 30 minutes.
 The first commercially available orthodontic adhesiveThe first commercially available orthodontic adhesive
was OIS adhesive system introduced by OIS company inwas OIS adhesive system introduced by OIS company in
1969 followed by GAC Internationals Bracket bond in1969 followed by GAC Internationals Bracket bond in
1970.1970.
 In 1979 survey in the united states, gorelick found thatIn 1979 survey in the united states, gorelick found that
93% of the orthodontists used bonding for bracket93% of the orthodontists used bonding for bracket

Bracket bonding:Bracket bonding:
 Success in bonding requires understanding ofSuccess in bonding requires understanding of
and adherence to accepted orthodontic andand adherence to accepted orthodontic and
preventive dentistry principles.preventive dentistry principles.
 The advantages and disadvantages of bondingThe advantages and disadvantages of bonding
versus banding of different teeth must beversus banding of different teeth must be
weighed according to each practitioner'sweighed according to each practitioner's
preferences, skill, and experience.preferences, skill, and experience.
 Bonding should be considered as only part of aBonding should be considered as only part of a
modern preventive package that also includes amodern preventive package that also includes a
strict oral hygiene program, fluoridestrict oral hygiene program, fluoride
supplementation, and the use of simple yetsupplementation, and the use of simple yet
effective appliances.effective appliances.

Advantages andAdvantages and
disadvantages:disadvantages:

 Optimal performance in bonding of orthodonticOptimal performance in bonding of orthodontic
attachments offers many advantages when comparedattachments offers many advantages when compared
with conventional banding:with conventional banding:
1.1. It is esthetically superior.It is esthetically superior.
2.2. It is faster and simpler.It is faster and simpler.
3.3. It results in less discomfort for the patient (no bandIt results in less discomfort for the patient (no band
seating and separation).seating and separation).
4.4. Arch length is not increased by band material.Arch length is not increased by band material.
5.5. It allows more precise bracket placement (aberrantIt allows more precise bracket placement (aberrant
tooth shape does not result in difficult banding and poortooth shape does not result in difficult banding and poor
attachment position).attachment position).
6.6. Bonds are more hygienic than bands, therefore anBonds are more hygienic than bands, therefore an
improved gingival and periodontal condition is possibleimproved gingival and periodontal condition is possible
and better access for cleaning is available.and better access for cleaning is available.
7.7. Partially erupted (or fractured) teeth can be controlled.Partially erupted (or fractured) teeth can be controlled.

8.8. Mesiodistal (proximal) enamel reduction is possibleMesiodistal (proximal) enamel reduction is possible
during treatment .during treatment .
9.9. Attachments may be bonded to artificial tooth surfacesAttachments may be bonded to artificial tooth surfaces
(e.g., amalgam, porcelain, gold) and to fixed;(e.g., amalgam, porcelain, gold) and to fixed;
bridgework.bridgework.
10.10. Interproximal areas are accessible for compositeInterproximal areas are accessible for composite
buildups.buildups.
11.11. Caries risk under loose bands is eliminated.Caries risk under loose bands is eliminated.
Interproximal caries can be detected and treated. NoInterproximal caries can be detected and treated. No
band spaces are present to close at the end ofband spaces are present to close at the end of
treatment.treatment.
12.12. No large inventory of bands is needed.No large inventory of bands is needed.
13.13. Brackets may be recycled, further reducing the cost.Brackets may be recycled, further reducing the cost.
14.14. Lingual brackets, invisible braces, can be used whenLingual brackets, invisible braces, can be used when
the patient rejects visible orthodontic appliances.the patient rejects visible orthodontic appliances.

 some disadvantages of bonding are apparent:some disadvantages of bonding are apparent:
1.1. A bonded bracket has a weaker attachment than aA bonded bracket has a weaker attachment than a
cemented band. Therefore it is more likely that a bracketcemented band. Therefore it is more likely that a bracket
will come off rather than that a band will becomewill come off rather than that a band will become
loosened.loosened.
2.2. Some bonding adhesives are not sufficiently strong.Some bonding adhesives are not sufficiently strong.
3.3. Better access for cleaning does not necessarilyBetter access for cleaning does not necessarily
guarantee better oral hygiene and improved gingivalguarantee better oral hygiene and improved gingival
condition, especially if excess adhesive extends beyondcondition, especially if excess adhesive extends beyond
the bracket base.the bracket base.
4.4. The protection against interproximal caries provided byThe protection against interproximal caries provided by
well contoured cemented bands is absent.well contoured cemented bands is absent.
5.5. Bonding is more complicated when lingual auxiliaries areBonding is more complicated when lingual auxiliaries are
required or if headgears are attached.required or if headgears are attached.
6.6. Rebonding a loose bracket requires more preparationRebonding a loose bracket requires more preparation
than recementing a loose band.than recementing a loose band.
7.7. Debonding is more time-consuming than debanding be-Debonding is more time-consuming than debanding be-
cause removal of adhesive is more difficult than removalcause removal of adhesive is more difficult than removal
of cement.of cement.

Classification of bondingClassification of bonding
adhesives:adhesives:
 First generation adhesivesFirst generation adhesives – used Glycerophosphoric– used Glycerophosphoric
acid dimethacrylate to provide bifunctional resinacid dimethacrylate to provide bifunctional resin
moleculemolecule
 The hydrophillic phosphate part reacted with calciumThe hydrophillic phosphate part reacted with calcium
ions, & the hydrophobic methacrylate groups bonded toions, & the hydrophobic methacrylate groups bonded to
the acrylic resin.the acrylic resin.
 Low bond strengthLow bond strength
 eg: The First commercial system of this type iseg: The First commercial system of this type is
Cervident, S.S. whiteCervident, S.S. white

 Second generation adhesivesSecond generation adhesives (late 1970’s)–(late 1970’s)–
chloro-substituted phosphate esters of variouschloro-substituted phosphate esters of various
monomers were used, bonding was by ionic bond tomonomers were used, bonding was by ionic bond to
calcium by chlorophosphate group.calcium by chlorophosphate group.
 Ashesion was short term & bond eventually hydrolysedAshesion was short term & bond eventually hydrolysed
 eg: Clearfil, Scotch Bond, Bond Lite (sybron/kerr) J&Jeg: Clearfil, Scotch Bond, Bond Lite (sybron/kerr) J&J
Dentin bonding agentDentin bonding agent
 Third generation adhesivesThird generation adhesives – involved 2 approaches– involved 2 approaches
1) modification of the smear layer to improve properties1) modification of the smear layer to improve properties
2) removal of smear layer without disturbing the plug that2) removal of smear layer without disturbing the plug that
occluded the dentinal tubulesoccluded the dentinal tubules
 The use was more complex and required 2 to 3The use was more complex and required 2 to 3
applications.applications.
 eg: mirage bond, gluma bonding system,eg: mirage bond, gluma bonding system, Scotch bond 2Scotch bond 2
dentin bonding system, Prisma Universal Bond 2dentin bonding system, Prisma Universal Bond 2

 Fourth generation adhesiveFourth generation adhesive – all bond- 2 system– all bond- 2 system
consists of 2 primers and an unfilled resin adhesive, thisconsists of 2 primers and an unfilled resin adhesive, this
system bonds composite not only to dentin but to mostsystem bonds composite not only to dentin but to most
related surfaces like enamel, casting alloys, amalgamrelated surfaces like enamel, casting alloys, amalgam
and porcelain.and porcelain.
 eg: All bond 2 (Bisco), Scotch Bond multipurpose (3M) ,eg: All bond 2 (Bisco), Scotch Bond multipurpose (3M) ,
Prime and Bond (Probond, dentsply), Solid Bond (kulzer)Prime and Bond (Probond, dentsply), Solid Bond (kulzer)
, Optibond (sybron/kerr) , Permaquick (ultradent) ,, Optibond (sybron/kerr) , Permaquick (ultradent) ,
Imperiva bond (Shofu).Imperiva bond (Shofu).
 Fifth generation adhesiveFifth generation adhesive – the most recent product is– the most recent product is
the single bond adhesive, this system is more simple tothe single bond adhesive, this system is more simple to
use as is needs only a single step application, reporteduse as is needs only a single step application, reported
as “one coat, one bond & one cure technology system”as “one coat, one bond & one cure technology system”
 eg: one bottle systems, Self etching primer bondingeg: one bottle systems, Self etching primer bonding
systemssystems

 Sixth generation adhesivesSixth generation adhesives – The sixth generation– The sixth generation
bonding systems are characterized by the possibility tobonding systems are characterized by the possibility to
achieve a proper bond to enamel and dentin using onlyachieve a proper bond to enamel and dentin using only
one solution.one solution.
 The first evaluation of these systems showed sufficientThe first evaluation of these systems showed sufficient
bond to conditioned dentin while bond to enamel wasbond to conditioned dentin while bond to enamel was
less effective.less effective.
 eg: Clearfil linear bond 2, Resulcin Aqua Prime+eg: Clearfil linear bond 2, Resulcin Aqua Prime+
Monobond, Prompt L PopMonobond, Prompt L Pop
 Seventh generation adhesives-Seventh generation adhesives-
 the first no-mix, self etching, self priming, single bottlethe first no-mix, self etching, self priming, single bottle
adhesiveadhesive
 It eliminates the uncertainty of mixing, and thus, anyIt eliminates the uncertainty of mixing, and thus, any
resulting technique sensitivity.resulting technique sensitivity.

 It also eliminates the etching step, and by accomplishingIt also eliminates the etching step, and by accomplishing
the priming and the bonding of dental surfacesthe priming and the bonding of dental surfaces
simultaneously, simplifies the adhesive proceduresimultaneously, simplifies the adhesive procedure
tremendouslytremendously
 Eg: i bondEg: i bond
 Eighth generation adhesives-Eighth generation adhesives- in this there is a stablein this there is a stable
nanofiller that will not settle out of dispersion, it isnanofiller that will not settle out of dispersion, it is
suitable for direct and indirect restorationssuitable for direct and indirect restorations
 Eg: single bond (3M ESPE), optic bond solo plus, adperEg: single bond (3M ESPE), optic bond solo plus, adper
single bond.single bond.

Bonding procedure:Bonding procedure:
 The steps involved in bracket bonding on facial orThe steps involved in bracket bonding on facial or
lingual surfaces are as follows:lingual surfaces are as follows:
 Cleaning -Cleaning - Cleaning of the teeth with pumice removesCleaning of the teeth with pumice removes
plaque and the organic pellicle that normally covers allplaque and the organic pellicle that normally covers all
teeth.teeth.
 One must exercise care to avoid traumatizing theOne must exercise care to avoid traumatizing the
gingival margin and initiating bleeding on teeth that aregingival margin and initiating bleeding on teeth that are
not fully erupted.not fully erupted.

 Enamel conditioning –Enamel conditioning –
1.1. Moisture Control:Moisture Control:
 Lip expanders and cheekLip expanders and cheek
retractorsretractors
 Saliva ejectorsSaliva ejectors
 Tongue guards with biteTongue guards with bite
blocksblocks
 Salivary duct obstructorsSalivary duct obstructors
 Cotton or gauze rollsCotton or gauze rolls

2.2. Enamel Pretreatment:Enamel Pretreatment:
 After the operative field has been isolated, theAfter the operative field has been isolated, the
conditioning solution or gel is applied over theconditioning solution or gel is applied over the
enamel surface for 15 to 30 seconds.enamel surface for 15 to 30 seconds.
 When etching solutions are used, the surfaceWhen etching solutions are used, the surface
must be kept moist by repeated applications.must be kept moist by repeated applications.
 To avoid damaging delicate enamel rods, careTo avoid damaging delicate enamel rods, care
should be taken not to rub the liquid onto theshould be taken not to rub the liquid onto the
teethteeth
 At the end of the etching period, the etchant isAt the end of the etching period, the etchant is
rinsed off the teeth with abundant water spray.rinsed off the teeth with abundant water spray.
 The teeth are dried thoroughly with a moistureThe teeth are dried thoroughly with a moisture
and oil free air source to obtain dull frostyand oil free air source to obtain dull frosty
appearance.appearance.

 Sealing –Sealing –
 The teeth are completely dryThe teeth are completely dry
and frosty white, a thin layerand frosty white, a thin layer
of bonding agent (sealant,of bonding agent (sealant,
primer) may be painted overprimer) may be painted over
the etched enamel surface.the etched enamel surface.
 The coating may be thinnedThe coating may be thinned
by a gentle air burst for 1 to 2by a gentle air burst for 1 to 2
seconds.seconds.
 Some investigators concludeSome investigators conclude
that an intermediate resin isthat an intermediate resin is
necessary to achieve propernecessary to achieve proper
bond strength.bond strength.
 some indicate thatsome indicate that
intermediate resin isintermediate resin is
necessary to improvenecessary to improve
resistance to micro leakage;resistance to micro leakage;
others feel intermediate resinothers feel intermediate resin
is necessary for both reasonsis necessary for both reasons

 Moisture-Insensitive Primers:Moisture-Insensitive Primers:
 In an attempt to reduce the bond failure rates underIn an attempt to reduce the bond failure rates under
moisture contaminations, hydrophilic primers that canmoisture contaminations, hydrophilic primers that can
bond in wet fields (Transbond MIP, 3M/Unitek, Monrovia,bond in wet fields (Transbond MIP, 3M/Unitek, Monrovia,
California; and Assure, Reliance Orthodontics, Itasca,California; and Assure, Reliance Orthodontics, Itasca,
Illinois) have been introduced as a potential solution.Illinois) have been introduced as a potential solution.
 Bond strengths were significantly lower under wetBond strengths were significantly lower under wet
conditions than in dry conditions, the hydrophilic primersconditions than in dry conditions, the hydrophilic primers
may be suitable in difficult moisture-control situations.may be suitable in difficult moisture-control situations.
 In some instances of second molar bonding and whenIn some instances of second molar bonding and when
there is risk for blood contamination on half erupted teeththere is risk for blood contamination on half erupted teeth
and on impacted canines.and on impacted canines.
 The hydrophilic resin sealants or primers polymerize inThe hydrophilic resin sealants or primers polymerize in
the presence of a slight amount of water, but they will notthe presence of a slight amount of water, but they will not
compensate routinely for saliva contamination.compensate routinely for saliva contamination.

 Self-Etching PrimersSelf-Etching Primers
 Combining conditioning and priming into oneCombining conditioning and priming into one
step may result in improvement in time and cost-step may result in improvement in time and cost-
effectivenesseffectiveness
 The main feature of the single -step etch/primerThe main feature of the single -step etch/primer
bonding systems is that no separate acidbonding systems is that no separate acid
etching of the enamel and subsequent rinsingetching of the enamel and subsequent rinsing
with water and air spray is required; the liquidwith water and air spray is required; the liquid
itself has a component that conditions theitself has a component that conditions the
enamel surface.enamel surface.
 The active ingredient of the self-etching primersThe active ingredient of the self-etching primers
(SEPs) is a methacrylated phosphoric acid ester(SEPs) is a methacrylated phosphoric acid ester
that dissolves calcium from hydroxyapatitethat dissolves calcium from hydroxyapatite

 Three mechanisms act to stop the etching process:Three mechanisms act to stop the etching process:
 The acid groups attached to the monomer areThe acid groups attached to the monomer are
neutralized by forming a complex with calcium fromneutralized by forming a complex with calcium from
hydroxyapatite.hydroxyapatite.
 Second, as the solvent is driven from the primer duringSecond, as the solvent is driven from the primer during
the airburst step, the viscosity rises, slowing thethe airburst step, the viscosity rises, slowing the
transport of acid groups to the enamel interface.transport of acid groups to the enamel interface.
 Finally, as the primer is light cured and the primerFinally, as the primer is light cured and the primer
monomers are polymerized, transport of acid groups tomonomers are polymerized, transport of acid groups to
the interface is stopped.the interface is stopped.
 The minimal etch obtained with the SEPs indicates thatThe minimal etch obtained with the SEPs indicates that
the majority of the bond may be more of a chemicalthe majority of the bond may be more of a chemical
bond with the calcium in the enamel than the mechanicalbond with the calcium in the enamel than the mechanical
achieved with a conventional phosphoric acid.achieved with a conventional phosphoric acid.

 Bonding -Bonding -
 Immediately after all teeth to be bonded haveImmediately after all teeth to be bonded have
been painted with sealant or primer, the operatorbeen painted with sealant or primer, the operator
should proceed with the actual bonding of theshould proceed with the actual bonding of the
attachmentsattachments
 The recommended bracket bonding procedureThe recommended bracket bonding procedure
(with any adhesive) consists of the following(with any adhesive) consists of the following
steps:steps:
 TransferTransfer
 PositioningPositioning
 FittingFitting
 Removal of excessRemoval of excess

Transfer:Transfer:

positioningpositioning

Fitting:Fitting:

Removal of excess:Removal of excess:

 It is important to removeIt is important to remove
the excess adhesive tothe excess adhesive to
prevent or minimizeprevent or minimize
gingival irritation andgingival irritation and
plaque buildup aroundplaque buildup around
the periphery of thethe periphery of the
bonding base. Thisbonding base. This
reduces the periodontalreduces the periodontal
damage and possibilitydamage and possibility
of decalcification, andof decalcification, and
improves estheticsimproves esthetics

Types of adhesives:Types of adhesives:
 Two basic types of dental resins may be usedTwo basic types of dental resins may be used
for orthodontic bracket bonding. Both arefor orthodontic bracket bonding. Both are
polymers and are classified aspolymers and are classified as
 acrylic or diacrylate resins.acrylic or diacrylate resins.
 Both types of adhesive exist in filled or unfilledBoth types of adhesive exist in filled or unfilled
forms.forms.
 The acrylic resins are based on self-curingThe acrylic resins are based on self-curing
acrylics and consist of methyl-methacrylateacrylics and consist of methyl-methacrylate
monomer and ultrafine powder.monomer and ultrafine powder.
 Most diacrylate resins are based on the acrylicMost diacrylate resins are based on the acrylic
modified epoxy resinmodified epoxy resin

 No-mix adhesivesNo-mix adhesives ::
 No-mix adhesives set, when one paste under lightNo-mix adhesives set, when one paste under light
pressure is brought together with a primer fluid on thepressure is brought together with a primer fluid on the
etched enamel and bracket backing or when anotheretched enamel and bracket backing or when another
paste on the tooth is to be bonded.paste on the tooth is to be bonded.
 one adhesive component is applied to the bracket baseone adhesive component is applied to the bracket base
while another is applied to the dried etched tooth.while another is applied to the dried etched tooth.
 As soon as the bracket is positioned precisely, theAs soon as the bracket is positioned precisely, the
bracket is pressed firmly into place and curing occurs,bracket is pressed firmly into place and curing occurs,
usually within 30 to 60 secondsusually within 30 to 60 seconds
 clinical bonding procedure are simplified with the no-mixclinical bonding procedure are simplified with the no-mix
adhesives.adhesives.

 In vitro tests have shown that liquid activators of the no-In vitro tests have shown that liquid activators of the no-
mix systems are toxic; allergic reactions have beenmix systems are toxic; allergic reactions have been
reported in patients, dental assistants, and doctors whenreported in patients, dental assistants, and doctors when
such adhesives were used (AJO- 1981)such adhesives were used (AJO- 1981)

 Light-polymerized adhesives :Light-polymerized adhesives :
 These resins offer the advantage of extended, workingThese resins offer the advantage of extended, working
time.time.
 This in turn provides the opportunity for assistants toThis in turn provides the opportunity for assistants to
place the brackets, with the orthodontist following up withplace the brackets, with the orthodontist following up with
any final positioning.any final positioning.
 Light-cured resins used with metal brackets are usuallyLight-cured resins used with metal brackets are usually
dual-cure resins incorporating light initiators and adual-cure resins incorporating light initiators and a
chemical catalyst.chemical catalyst.
 Bond strength for light-activated materials is reported toBond strength for light-activated materials is reported to
be comparable in vitro to those of chemically curedbe comparable in vitro to those of chemically cured
composite but the material may not be as reliable in vivo.composite but the material may not be as reliable in vivo.
(BJO- 1984)(BJO- 1984)
 Light-cured adhesives are particularly useful in situationsLight-cured adhesives are particularly useful in situations
in which a quick set is required, such as rebonding onein which a quick set is required, such as rebonding one
loose bracket or when placing an attachment on anloose bracket or when placing an attachment on an
impacted canine after surgical uncovering with the riskimpacted canine after surgical uncovering with the risk
for bleeding.for bleeding.

 Fluoride releasing, visible light-curing adhesives are alsoFluoride releasing, visible light-curing adhesives are also
available, but further long-term clinical testing of theiravailable, but further long-term clinical testing of their
bond strength, durability, and caries-preventive effect isbond strength, durability, and caries-preventive effect is
necessary.necessary.
 Metallic and ceramic brackets precoated with curedMetallic and ceramic brackets precoated with cured
composite and stored in suitable containers are practicalcomposite and stored in suitable containers are practical
in use.in use.
 Such brackets have consistent quality of adhesive,Such brackets have consistent quality of adhesive,
reduced flash, reduced improved cross-infection control,reduced flash, reduced improved cross-infection control,
and adequate strength.and adequate strength.

Bibliography:Bibliography:
 T.M Graber, Robert L Vanarsdall, Katherine W.L;T.M Graber, Robert L Vanarsdall, Katherine W.L;
Orthodontic current principles and techniques; 4thOrthodontic current principles and techniques; 4th
edition; Elsevier publication; pg 579-594edition; Elsevier publication; pg 579-594
 T.M.Graber, Brainerd F Swain; orthodontic currentT.M.Graber, Brainerd F Swain; orthodontic current
principles and techniques; 1st edition; jaypee brothers;principles and techniques; 1st edition; jaypee brothers;
pg 485-503pg 485-503
 Raymond C Thurow; Edgewise Orthodontics; 4th edition;Raymond C Thurow; Edgewise Orthodontics; 4th edition;
Mosby Publication;1982; pg 196-218Mosby Publication;1982; pg 196-218
 William R Profitt; contemporary orthodontics; 4th edition;William R Profitt; contemporary orthodontics; 4th edition;
mosby Elsevier publication; pg 411-417mosby Elsevier publication; pg 411-417

 Kenneth J Anusavice; Philips Science of dentalKenneth J Anusavice; Philips Science of dental
materials; 11th edition; Elsevier publication; pg 381-396,materials; 11th edition; Elsevier publication; pg 381-396,
461-488461-488
 Nicola Johnson; Orthodontic banding cements; JournalNicola Johnson; Orthodontic banding cements; Journal
of orthodontics; September 2000; pg 283-287of orthodontics; September 2000; pg 283-287

Thank youThank you

Bonding and banding

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