FACULTY OF DENTISTRY MANSOURA UNIVERSITY ORTHODONTIC DEPARTMENT Under Supervision of Proff.Dr. Maher FOUDA SOURCE: ORTHODONTIC BRACKET SELECTION, PLACEMENT AND DEBONDING. DR HARIS KHAN

1. DEBONDING OF
ORHTODONTIC
BRACKETS
ORTHODONTIC BRACKETS
SELECTION, PLACEMENT AND DEBONDING Dr. Haris Khan
PREPARED BY Safa Eltabey
UNDER SUPERVISION OF PROF.DR.MAHER FOUDA

2. • Fixed orthodontic brackets are temporary appliances which are
needed to be removed either to be repositioned or at the end of
orthodontic treatment.
• The removal process is either called debonding or debracketing.
• Debonding procedure in orthodontics can be divided into two steps2.
Step 1: Removal of bracket from the tooth
Step 2: Removal of adhesive remnants from
enamel

3. • In debonding orthodontic brackets from the tooth the site
of bond failure is very important.
• Bond failure is accessed by adhesive remnant index
(ARI)
• Bond failure can be adhesive and occur between bracket
and adhesive….or between enamel and adhesive…. or it
can be cohesive occurring between the adhesives cement
itself…..

4. 0 2
3
31
1
It is important to avoid iatrogenic
damages to the tooth during bracket and
adhesive remnants removal as improper
debonding results in cracks on enamel
surface and enamel prisms fracture.
Esthetic problems, tooth sensitivity,
increasing risk of caries and pulp
necrosis may also be seen after improper
debonding.

5. Different methods of deboning orthodontic
brackets are as follow:
• 1. Mechanical debonding
• 2. Debonding by solvents
• 3. Debonding by Notching
• 4. Ultrasonic debonding
• 5. Impulse debonding
• 6. Thermal debonding

6. 1. Mechanical debonding of orthodontic
brackets using debonding plier
• Which can be either:
A)Base method OR B)Wing method.

7. • Base Method:
i. Horizontal or mesiodistal base method
ii. Vertical base method
iii. Diagonal method

8. Advantages of base method:
1. 1.5 times more debonding force is required as compared to
wing method.
2. produce sudden bond failure as heavy forces are being
applied by the plier so there are chances of injury to the
surrounding soft tissue by the plier beaks.
3. the bond failure usually occur within the adhesive or at the
level of enamel adhesive interference. So there are less
chances of bracket distortion and many debonded brackets
can be recycled or rebpositioned after this method.

10. Wing Method
• Wing method of debonding is
similar to base method of
debonding with the only difference
is that the beaks or blades of the
pliers are placed at the level of
bracket wings rather than at the
base level.
• It has horizontal, vertical and
diagonal variations like that of
base method.

11. • Two types of forces can be
applied to metal brackets by
wing method.
1. Squeezing force (need thin
bladed plier).
2. Subsequent squeezing and
peel off force( when thicker
bladed pliers are used as
Weingart or Howe pliers).

12. Bracket removing plier or Debonding
plier
• A debonding plier. The
plier can be used with both
base and wing method.
• Enamel damage was found
only 4 % with these pliers.
• Debonding plier with 2 mm
gap between
• the beaks on full closure.

13. Ligature cutters/Side Cutters
• Only base method of debonding
can be used by this cutter.
• Clinician don't have to bear
extra cost to buy a new
instrument.
• But:
• There are greater chances of
soft tissue injury with sharp
beaks of ligature cutters.
• As heavy forces are transmitted
at bracket adhesive interference
there is greater risk of enamel
damage.

14. • Many clinicians use
straight wire cutter with
base method of
debonding.
• The blades of straight
wire cutter are thicker than
ligature cutter so there are
greater chances of bracket
base distortion.

15. Weingart plier
• Weingart plier is used only with
the wing method of debonding.
• Subsequent squeezing and peel
off force is given.

16. Howe plier
• Howe plier is also used with
wing method of mechanical
debonding
• Owing to broader tip of
Howe plier debonding forces
are evenly distributed
throughout the bracket and
there are less chances of
enamel damage.

17. Lift-off Debonding Instrument (LODI)
• LODI is a pistol grip debonding instrument
in which a wire loop is used to engage the
bracket wings.
• Instrument is placed over the bracket and
one of the wings is engaged in the wire
loop of the plier.
• Then trigger is lightly squeezed until both
the beaks of instrument rest evenly on the
tooth surface.
• After proper seating of plier the trigger is
squeezed slightly harder until the bracket is
lifted from the tooth surface.
• By squeezing the trigger of the plier a
tension force is delivered to the brackets
wing hooked in the wire loop and bracket is
debonded

18. • The advantages of LODI are:
1. LODI doesn't cause bracket base
distortion.
2. Less force is required10 for
debonding when tension is applied.
3. Patient experience less pain11 as
compared to debonding with side
cutters.
4. Brackets can be recycled6 and
reused after debonding if wire is left
in place or a slot keeper is used.
• But LODI is not routine part of
dental office & there are greater
chances of enamel damage.

19. Bracket and adhesive removing plier
• Used like a band removing plier
• One end of the plier which contains a
plastic head (Teflon pad) is placed
over the incisal or occlusal part of
tooth and the other metal end of the
plier grip the bracket from the
gingival side close to bracket adhesive
interference.
• Giving squeezing force to the plier
delivers a shear force to the bracket.
• The same plier can be used for
adhesive remnants

20. Self ligating brackets debonding
• Self-ligating brackets can also be
debonded by conventional method.
• Ideally the self ligating clip of the
bracket should be open while
debonding the bracket.
• Usually base method is referred if
self-ligating brackets needed to be
recycled.
• Some manufacturers recommend
special pliers for debonding their
self ligating brackets

21. Lingual brackets debonding
• Usually a
debonding plier is
used for lingual
brackets with
both base and
wing method.

23. Mechanical debonding of plastic brackets
• Plastic brackets can be
debonded with both base
and wing method but base
method is preferred

25. Mechanical debonding of ceramic
brackets
• As most fixed appliance cases in orthodontic practice are done with
metal brackets so orthodontist use their instinct mechanical
debonding techniques of metal brackets to ceramic brackets which
result in either bracket fracture or enamel damage.
• The reason behind this is that orthodontist failed to appreciate two
main differences between ceramics and metal brackets. These are:
1) Bond strength
2) Physical properties

26. Mechanical debonding of ceramic
brackets

27. The tensile strength of enamel is 14.5 MPa ,
and it has been reported that enamel fracture
can occur at bracket bond strength of 13.5
MPa
To save enamel fracture during debonding
clinical acceptable bond strength shouldn‘t
exceed 13.5 MPa. The minimum bond
strength to withstand orthodontic and
masticatory force is recommended between 6
to 8 MPa 15 for all types of brackets. The
bond strength of ceramic brackets whether it is
in chemical or mechanical retention base is
almost always greater than metal brackets and
is usually greater than 13.5 MPa. Theoretically
any bracket that has bond strength greater than
13.5 MPa should always fracture the enamel.

28. • Debonding methods
For mechanical debonding of ceramic brackets the
best available option to debond the bracket is
follow manufacturer recommendations.
Before debonding any ceramic bracket by
mechanical means always remove flash around the
bracket base with a carbide bur on slow or high
speed hand piece using a water coolant.
This will allow easy grip of the plier in base
method of debonding and also help decrease bond
strength of the bracket.
Ceramic brackets being brittle can easily fracture
and can
dislodge in oral cavity of patient or fragments of
bracket can fly and may enter the eyes.
Protective dental glasses should be used by the
dentist and his assistant

32. Advantages of mechanical debonding of ceramic
brackets are:
1. Time efficient
2. Most debonding pliers are normal armamentarium of
orthodontic office.
The disadvantages associated with mechanical
debonding of ceramic brackets are:
1. Brittleness may cause problems such as breakage of
bracket during mechanical sdebonding.
2. Aspiration of fragments if bracket is fractured or
failed. As ceramic brackets are radiolucent it is almost
impossible to locate them if aspirated.
3. Injury by the flying debris to patient oral mucosa or
clinician eyes on bracket fracture.
4. Portion of broken bracket need to be grounded with
high speed handpiece thus increasing the debonding
time.
5. The probability of enamel damage is greater if the
integrity of tooth structure is already compromised by
presence of developmental defects, enamel cracks,
large restorations and nonvital teeth.
As ceramic brackets are harder than
stainless steel so debonding of the
brackets cause wear of the instrument.
Debonding pliers with replaceable
tips are usually used.

35. Ultrasonic debonding
Conventional mechanical debonding
techniques for ceramic brackets
recommended by manufacturers are
associated with 10-35 % of brackets
fracture. To avoid ceramic brackets fracture
during debonding use of ultrasonic devices
have been advocated.
Ultrasonic devices can also be used to
debond metal and plastic brackets.
Vibrating metal tip erodes adhesive and
creates a purchase point underneath the
bracket base. Ultrasonic tip can cause
cohesive bond failure within the adhesive
or bond failure occurs at enamel adhesive
interference. So bracket damage is avoided.

36. Choice of Ultrasonic Scalers
Two different types of ultrasonic scalers are
commercially available. These are piezoelectric
and magnetostrictive scalers.
Theoretically both these types of scalers can be
used for bracket debonding
In literature only magnetostrictive scalers with
special tips have been used to debond ceramic
brackets but
in some case reports in non-index journals
piezoelectric scalers have also been used. Also
piezoelectric scalers can work at greater
frequency than magnetostrictive scalers and the
final enamel surface is also smooth.
In magnetostrictive scalers usually 30 KHz
scalers are preferred over 25 KHz scalers as they
are less noisy and of course have a greater
vibration speed.
.

37. Impulse debonding
• Impulse debonding have been
proposed 6, 31 to debond metal
brackets without distorting their
base and slot characteristics so
that they can be recycled and
reused. Impulse debonding
shouldn't be used with ceramic
brackets as it will cause bracket
fracture.
• The idea has been inspired from
crown removal in
prosthodontics.

39. Thermal debonding
Methods of thermal debonding
1. Hot instruments Tips
Thermal debonding by hot instruments tips have been
abandoned in orthodontic practice.
2. Electrothermal method
uses electric energy to transfer heat to the bracket for
debonding.
Various elctrothermal debonders were made for
commercial use in 1980s and 90s. They were quite useful
for chemical retention base of ceramic brackets. With
improvement in design of bracket base and other methods
available these instrument went into disuse.
3. Laser debonding

40. Laser debonding

41. How laser debond brackets
Some lasers heat the brackets and the hot brackets causes the adhesive
to fail while other laser passes through the brackets and directly affect
the adhesive by burning its liquid (water or monomer) contents or
effecting its composition.
• Other factors must be kept in mind to avoid iatrogenic damages to
tooth structures, the power density of lasers mentioned in Watts, time
period in seconds, mode of operation of lasers that is continuous or
pulse, mode of application which can either be point application or
scanning mode application. Composition of adhesive and geometry
of brackets also play crucial role during debonding.