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University
Journal of
Dental Sciences
DEBONDING IN ORTHODONTICS :
A REVIEW
Review
Articles
1
Neelutpal Bora, 2Nabanita Baruah
Lecturer, 2Reader, Department of Orthodontics and Dentofacial Orthopedics
Regional Dental College, Gawhati.
1
Abstract: The objectives of debonding are to remove the attachment and all the adhesive resin
from the tooth and restore the surface as closely as possible to its pretreatment condition
without inducing iatrogenic damage. To obtain these objectives, a correct technique is of
fundamental importance. Debonding may be unnecessarily time consuming and damaging to
the enamel if performed with improper technique or carelessly. The present article gives us an
overview of the best possible methods so as to have an ideally desired tooth structure after
debonding.
INTRODUCTION:
An expectation of beautiful smiles at the end of orthodontic
treatment is a primary concern to each patient, but is also
equally concerned with appearance while undergoing
treatment. Many attempts have been made by manufacturers
to meet this demand. Characteristic of an ideal orthodontic
appliance include good esthetics and optimum technical
performance. Reports of enamel fracture and cracks during
debonding has raised questions about the safety of various
procedures used to remove these attachments,1-4 although
the tensile strength of ceramic is greater than that of stainless
steel, less energy is used to cause fracture of ceramic brackets
compared with conventional stainless steel brackets.4 This
phenomenon is related to fracture toughness or the ability of a
material to resist fracture and ceramic brackets have
substancially less fracture toughness when compared to
stainless steel brackets.5,6The adhesion between the resin
and bracket base has increased to a point where the most
common site of bond failure during debonding has shifted
from bracket base- adhesive interface to enamel adhesive
interface which could increase the risk of enamel damage
Key word s:
Debonding, iatrogenic,
adhesive resin.
Source of support : Nil
Conflict of Interest : None
which is a less desirable.7-9 This shift has led to an increase in
the incidence of bond failures within the enamel surface.10
Different techniques used for debonding:
Manufacturers have developed various debonding techniques
specially for ceramic brackets, including the use of debonding
pliers and ligature cutting pliers to apply a squeezing force at
the bracket base as well as the application of a shear torsion
force with a specially designed instrument.6, 11 Alternate
debonding techniques that minimize the potential for bracket
failure as well as trauma to the enamel surface during
debonding. Ultrasonic debracketing tips uses specially
designed tips applied at the bracket adhesive junction.1,3, 57,12 Thermal debonding has also been suggested as a method
for debonding ceramic brackets.9,13
Clinical Procedures
Although several methods have been recommended in the
literature for bracket removal and adhesive cleanup, and some
discrepancy of opinion still exists.
The clinical debonding procedure may be divided in two
stages:
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1. Bracket removal
2. Removal of residual adhesive
Bracket removal: steel brackets (Fig.1)
Several different procedures for debracketing with pliers are
available. An original method was to place the tips of a twinbeaked pliers against the mesial and distal
edges of the bonding base and cut the brackets off between the
tooth and the base. Several pliers are available for this
purpose. A gentler technique is to squeeze
the bracket wings mesio distally and lift the bracket off with a
peel force. This is particularly useful on brittle, mobile, or
endodontically treated teeth. The brackets are deformed
easily and are less suitable for recycling when the latter
method is used. This is a recommended technique, in which
brackets are not deformed. This technique uses a peeling-type
force, which is most effective in breaking the adhesive bond.
A peel force, as in peeling an orange, creates peripheral stress
concentrations that cause bonded metal brackets to fail at low
force values.11-12 The break is likely to occur in the adhesive
bracket interface, thus leaving adhesive remnants on the
enamel. Attempts to remove the bracket by shearing it off (as
is done in removing bands) can be traumatic to the patient and
potentially damaging to the enamel.
fracture, which in practice requires grinding away the rest of
the bracket. Cutting the brackets off with gradual pressure
from the tips of twin-beaked pliers oriented mesiodistally
close to the bracket-adhesive interface is not recommended
because it might introduce horizontal enamel cracks. More
recent ceramic brackets have a mechanical lock base and a
vertical slot-that will split the bracket by squeezing.6-8
Separation is at the bracket-adhesive interface, with little risk
of enamel fracture. Low-speed grinding of ceramic brackets
with no water cool ant may cause permanent damage or
necrosis of dental pulps. Therefore water cooling of the
grinding sites is necessary. High-volume suction and eye
protection also are recommended to reduce the number of
ceramic particles spread about the operatory area. Finally,
thermal debonding the use of lasers have the potential to be
less traumatic and less risky for enamel damage, but these
techniques are still at an introductory stage.
Removal of residual adhesive
After debonding of brackets evaluation of residual adhesive
and sites of bond failure are recorded using Adhesive
Remnant Index (ARI) . It is a four scale index to determine
the amount of adhesive remnants on the enamel surface after
debracketing and was introduced by Artun and Bergland. 14
Adhesive Remnant Index (ARI)
Bracket removal: ceramic brackets (Fig.2)
With the introduction of ceramic brackets, a new concern over
enamel fracture and loss from debonding has arisen. Because
of differences in
bracket chemistry and bonding
mechanisms, various ceramic brackets behave differently on
debonding. For example, ceramic brackets using mechanical
retention cause fewer problems in debonding than do those
using chemical retention. In this regard, some knowledge
about the normal frequency, distribution, and orientation of
enamel cracks in young and in older teeth is important.
Ceramic brackets will not flex when squeezed with
debonding pliers. The preferred mechanical debonding is to
lift the brackets off with peripheral force application, much
the same as for steel brackets. Several tie-wings still may
Score 0 –
No adhesive left on the enamel.
Score 1 –
Less than half of the adhesive left on the
enamel.
Score 2 –
More than half of the adhesive left on the
enamel.
Score 3 –
All adhesive left on the tooth surface with
distinct impression of the bracket mesh.
Because of the color similarity between present adhesives and
enamel, complete removal of all remaining adhesive is not
achieved easily. Many patients may be left with incomplete
resin removal, which is not acceptable. Abrasive wear of
present bonding resins is limited, and remnants are likely to
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become unesthetically discolored
with time. The removal of excess adhesive may be
accomplished by (1) scraping with a sharp band or bondremoving (2) using a suitable bur and contraangle .(Fig.3)
Although the first method is fast and frequently successful on
curved teeth (premolars, canines), it is less useful on flat
anterior teeth. A risk also exists of creating significant scratch
marks. The preferred alternative is to use a suitable dome
tapered tungsten carbide bur (#1171 or #1172) in a contra
angle handpiece. Clinical experience and laboratory studies
indicate that about 30,000 rpm is optimal for rapid adhesive
removal without enamel damage. Light painting movements
of the bur should be used so as not to scratch the enamel.
Water cooling should not be used when the last remnants are
removed because water lessens the contrast with enamel.
Speeds higher than 30,000 rpm using fine fluted tungsten
carbide burs may be useful for bulk removal but are not
indicated closer to the enamel because of the risk of marring
the surface. Even ultra fine high-speed diamonds produce
considerable surface scratches. Slower speeds (10,000 rpm
and less) are ineffective, and the increased jiggling vibration
of the bur may be uncomfortable to the patient.
When all adhesive has been removed, the tooth surface may
be polished with pumice (or a commercial prophylaxis paste)
in a routine manner.
CHARACTERISTICS OF NORMAL ENAMEL
Apparently not every clinician is familiar with the dynamic
changes that continuously take place throughout life in the
outer, most superficial enamel layers. Because a tooth surface
is not in a static state, the normal structure differs
considerably between young, adolescent, and adult teeth.
Normal wear must be considered in any discussion of tooth
surface appearance after debonding. The characteristics are
visible on the clinical and microscopic levels.
The most evident clinical characteristics of teeth that have just
erupted into the oral cavity 3 perikymata that runs around the
tooth over its surface
By scanning electron microscope the open enamel prism ends
are recognized as holes In adult teeth the clinical picture
reflect and exposure to varying mechanical forces (e.g.,
brushing habits and abrasive food stuffs). In other words the
perikymata ridges are worn away and replace scratched
pattern .(Fig.4)
Influence on Enamel by Different Debonding Instruments
The condition of the enamel surface is evaluated according to
the ENAMEL SURFACE INDEX (ESI) system introduced
by Bjorn U. Zachrisson and Jon Arthun.15
Score 0 = Perfect surface. No scratches, distinct intact
perikymata.
Score I = Satisfactory surface. Fine scratches, some
perikymata.
Score 2 = Acceptable surface. Several marked and some
deeper scratches, no perikymata.
Score 3 = Imperfect surface. Several distinct deep and coarse
scratches, no perikymata.
Score 4 = Unacceptable surface. Coarse scratches and deeply
marred appearance.
By proposing an enamel surface index with five scores (0to 4)
for tooth appearance and using replica scanning electron
microscopy and step-by-step polishing, Zachrisson and Artun
were able to compare different instruments commonly used in
debonding procedures and rank their degrees of surface
marring on young permanent teeth. (Fig.5)
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The study demonstrated that
(1) diamond instruments were unacceptable (score 4), and
even fine diamond burs produced coarse scratches and gave a
deeply marred appearance;
(2) medium sandpaper disks and green rubber wheel
produced similar scratches (score3) that could not be polished
away;
(3) fine sandpaper disks produced several considerable and
some even deeper scratches and a appearance largely
resembling that of adult teeth (score 2);
(4) plain cut and spiral fluted tungsten carbide burs operated
at about 25,000 rpm were the only instruments that provided
the satisfactory surface appearance (score 1); however, (5)
none of the instruments tested left the virgin tooth surface
with its perikymata intact (score 0).
The clinical implication of the study is that tungsten carbide
burs produced the finest scratch pattern with the least enamel
loss and are superior in their ability to reach difficult areas
pits, fissures, and along the gingival margin. For optimal
efficiency the bur must be replaced when it becomes blunt.
Increased diameter burs or high-speed equipment also may be
used for bulk removal. The oval tungsten carbide bur is useful
for removing adhesive remnants after debonding retainers
and brackets on the lingual surfaces of teeth. Tungsten carbide
burs can give the ideal tooth condition desired after
debonding .(Fig.6)
2.
3.
4.
5.
6.
7.
8.
9.
10.
CONCLUSION:
The present study suggests that an ideal debonding technique
should take the least time to debond the brackets with minimal
enamel damage and residual adhesive remaining on the
enamel surface. In order to achieve a desirable finish to any
orthodontic case after debonding tungsten carbide bur is
useful for removing adhesive remnants after debonding
retainers and brackets on all the surfaces of teeth.
BIBLIOGRAPHY
1. Boyer D, Engelhardt G, Samir E. Bishara: Debonding
orthodontic ceramic brackets by ultrasonic
11.
12.
13.
instrumentation. Am J Orthod Dentofacial Orthop: 1995;
108 (3): 262-266.
Eliades T, Viazis AD, Lekka M. : Failure mode analysis
of ceramic brackets bonded to enamel. Am J Orthod
Dentofacial Orthop 1993; 104 (1):21-26.
Williams L and Bishara SE. : Patient discomfort levels at
the time of debonding. Am J Orthod Dentofacial Orthop
1992; 101(4):313-319.
Theodorakopoulou LP, Sadowsky PL, Jacobson A,
Lacefield W. : Evaluation of the debonding
characteristics of 2 ceramic brackets: An in vitro study.
Am J Orthod Dentofacial Orthop 2004; 125: 329-336.
Jena AK, Duggal R and Mehrotra AK. : Physical
properties and clinical characterstics of ceramic
brackets: A comprehensive review. Trends Biomater.
Artif Organs : 2007:20 (2).
Karamouzos A, Athanasiou AE and Papadopoulos MA. :
Clinical characteristics and properties of ceramic
brackets : A comprehensive review. Am J Orthod
Dentofacial Orthop: 1997;112 (1): 34-40.
Bishara and Trulove. : Comparisions of different
techniques for ceramic brackets: An in vitro study. Part I.
Background and methods. Am J Orthod Dentofacial
Orthop: 1990; 98 (2):145-153.
Bishara and Trulove. : Comparisions of different
techniques for ceramic brackets: An in vitro study. Part
II. Background and methods. Am J Orthod Dentofacial
Orthop 1990; 98 (3):263-273.
Bishara SE, Fonseca JM, Boyer DB. : The use of
debonding pliers in the removal of ceramic brackets:
Force levels and enamel cracks. Am J Orthod
Dentofacial Orthop 1995; 108 (3):242-248.
Kitahara-Ceia FMF, Mucha JN and dos Santos PAM. :
Assessment of enamel damage after removal of ceramic
brackets. Am J Orthod Dentofacial Orthop: 2008; 134:
548-555.
Oliver RG. : The effect of different methods of bracket
removal on the amount of residual adhesive. Am J
Orthod Dentofacial Orthop 1988; 93(3): 196-200.
Krell KV, Courey JM, Bishara SE. : Orthodontic bracket
removal using conventional and ultrasonic debonding
techniques, enamel loss, and time requirements. Am J
Orthod Dentofacial Orthop1993; 103 (3):258-266.
Crooks M, Hood J and Harkness M. : Thermal
debonding of ceramic brackets: An in vitro study. Am J
Orthod Dentofacial Orthop: 1997; 111 (2):163-172.
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14. Artun and Bergland. : Clinical trials with crystal growth
conditioning as an alternative to acid-etch enamel
pretreatment. Am J Orthod 1984; 85 (4):333-340.
15. Zachrisson B, Arthun J. : Enamel surface after various
debonding procedures. Am J Orthod : 1979:75 (2):121137.
CORRESPONDENCE AUTHOR :
Dr. Neelutpal Bora
Lecturer,
Department of Orthodontics and Dentofacial Orthopedics
Regional Dental College, Guwahati, Assam
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