Download Distortion of Brackets by Conventional Debonding Technique

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10.5005/jp-journals-10021-1159
ORIGINAL ARTICLE
Distortion of Brackets by Conventional Debonding Technique
Distortion of Brackets by Conventional
Debonding Technique
1
Yogesh Gupta, 2K Sadashivas Shetty, 3Chandresh Shukla
ABSTRACT
Introduction: Various debonding techniques have been suggested by several investigators which claim to remove brackets from the tooth
with minimum distortion. The present study has been done to compare three conventional debonding techniques using debonding pliers.
Objective: To know the best method of debonding the brackets from the tooth surface with minimal distortion.
Materials and methods: The present study is done in vitro on extracted teeth. Thirty standard edgewise brackets with 0.022" × 0.028" were
bonded on to the teeth. Three groups were made to compare three different techniques. Occlusal side 'A' and gingival side 'B' of the wings
were marked. Optical profile projector with accuracy to 0.001 mm was used to measure the slot width and interwing distance accurately. An
indigenous bracket debonding plier was used in three different ways for comparison.
Results: Slot width: The minimum mean decrease in slot width was 0.027 in group 3. Interwing distance on ‘A’ side: Group 1 showed
significantly higher difference in interwing distance on ‘A’ side (0.061) as compared to groups 2 and 3 (0.019). Interwing distance on ‘B’ side:
The minimum mean decrease in interwing distance on ‘B’ side was 0.012 with group 3.
Discussion: A number of studies have been done to describe the effects of conventional debonding techniques on the tooth surface. In
most of the studies, different techniques were used with different bonding materials and different bracket system. This study has been
evaluated in three ways: (i) Change in slot width: The slot width got affected minimally when the brackets were deboned by holding them
gingivoocclusally with archwire into the slot and rotate it gingivoocclusally; (ii) change in interwing distance on occlusal side: Bracket
debonded by holding it gingivoocclusally and rotating it gingivoocclusally with or without holding archwire did not show any difference; (iii)
change in interwing distance on gingival side: Brackets debonded by holding it gingivoocclusally and rotating it gingivoocclusally with or
without holding archwire did not show much difference.
Conclusion: The brackets can be reused after recycling (provided they do not get distorted significantly). Among conventional debonding
techniques (with bracket removing plier), the best method found was to debond bracket by holding it occlusogingivally with the archwire into
the slot.
Keywords: Brackets, Debonding, Debonding plier, Optical profile projector, Slot width, Interwing distance.
How to cite this article: Gupta Y, Shetty KS, Shukla C. Distortion of Brackets by Conventional Debonding Technique. J Ind Orthod Soc
2013;47(4):207-210.
INTRODUCTION
Man is always striving for the new things to make his work
quick, comfortable and better. But at the same time, these things
create some new problems which become a challenge to him.
On completion of active orthodontic treatment, the brackets
are removed by different methods and after a reconditioning
process1 they may be reused on subsequent patients.2 This has
obvious economic advantages. M/s Esma Chemicals, Inc,
Highland Park, Illinois, USA (Advertisement, AJO, 1987) has
claimed an estimated saving of 5,000 Dollars per year per
clinician.
1,2
Professor and Head, 3Senior Lecturer
Department of Orthodontics, RKDF Dental College, Bhopal, Madhya
Pradesh, India
2
Department of Orthodontics, Bapuji Dental College and Hospital
Davangere, Karnataka, India
3
Department of Orthodontics, People’s College of Dental Sciences
and Hospital, Bhopal, Madhya Pradesh, India
1
Corresponding Author: K Sadashivas Shetty, Professor and Head
Department of Orthodontics, Bapuji Dental College and Hospital
Davangere, Karnataka, India, e-mail: [email protected]
Received on: 16/5/12
Accepted after Revision: 18/12/12
In conventional debonding techniques, the bracket is
debonded by debonding plier by holding it mesiodistally or
occlusogingivally without or with archwire filled into the
bracket slot or by force applied by the debonding plier or
ligature cutter positioned at the enamel/composite or composite/
bracket interface. The force necessary to break adhesive–
bracket or adhesive–tooth interface is sufficient to cause
deformation of the bracket. So, not all the brackets are suitable
for reconditioning since they may become distorted during
debonding procedure.
OBJECTIVE
This study was done to evaluate the best conventional method
of debonding.
MATERIALS AND METHODS
Materials
Thirty extracted premolars of orthodontic patients were taken
in this study irrespective of the quadrants. Teeth were divided
into three groups. Each group had 10 teeth.
All the teeth were without caries, except two teeth of group
A having Class I silver filling. Thirty standard edgewise 0.022"
× 0.030" brackets with mesh base (80/linear inch) were taken.
The Journal of Indian Orthodontic Society, October-December 2013;47(4):207-210
207
Yogesh Gupta et al
No mix adhesive Ortho-one was used to bond brackets on to
the teeth. An indigenous bracket debonding plier (resembling
ETM made Direct Bond Attachment Remover No. 628-011)
was used. Optical profile projector was used to measure slot
size and interwing distance. A piece of 0.022" × 0.028" straight
length stainless steel archwire was used to fill bracket slot. A
0.010 stainless steel ligature wire was used to tie the archwire
to the bracket.
Group 2 (no. 11-20): Bracket was debonded by holding it
gingivoocclusally and rotating it gingivoocclusally (without
archwire into the slot (Fig. 3).
Group 3 (no. 21-30): Bracket slot was filled with archwire piece
and then debonded by holding it gingivoocclusally and rotating
it gingivoocclusally (Fig. 4).
The slot width and interwing distance were measured the
same way as did before bonding.
Methods
All the 30 teeth were cleaned and numbered from 1 to 30.
Brackets numbered from 1 to 30 were bonded on to the teeth.
Teeth were fixed in Plaster of Paris and separate plaster blocks
were made to debond brackets by different methods. White
correction fluid was used to put mark on one side of base to
identify occlusal (A) side and gingival (B) side of the wings.
The slot width and interwing distances were measured with the
help of optical profile projector (Fig. 1). The teeth and brackets
were divided into three groups as follows:
RESULTS
Group 1 (no. 1-10): Brackets was debonded by holding it
mesiodistally at the base of the bracket and rotating it in
anticlockwise direction (Fig. 2).
A, B and C represent groups 1, 2 and 3 respectively. Tables 1
to 3 show slot widths, interwing distances on occlusal and
gingival sides before bonding, after debonding and the
differences after debonding. Results were evaluated individually
after debonding.
1. Slot width: In group 1, the mean decrease in slot width
after debonding was 0.049 mm. In group 2, the mean
decrease was 0.033 mm. In group 3, the mean decrease
was 0.027 mm.
2. Interwing distance on ‘A’ side: In group 1, the mean
decrease in interwing distance on occlusal side was
Fig. 1: Optical profile projector
Fig. 2: Debonding plier holding the bracket mesiodistally
Fig. 3: Debonding plier holding the bracket occlusogingivally
Fig. 4: Debonding plier holding the bracket (with wire)
occlusogingivally
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Distortion of Brackets by Conventional Debonding Technique
0.061 mm. In group 2, the mean decrease was 0.019 mm.
In group 3, the mean decrease was 0.019 mm. Group 1
showed significantly higher difference in interwing distance
on ‘A’ side as compared to groups 2 and 3.
3. Interwing distance on ‘B’ side: In group 1, the mean
decrease in interwing distance on gingival side was
0.035 mm. In group 2, the mean decrease was 0.015. In
group 3, the mean decrease in interwing distance on gingival
side was 0.012 mm.
deboding pliers are used. Knosel et al9 compared four methods.
They suggested that the use of the side cutter and the bracket
removing plier would not be better than use of LODI and
Coronaflex. The study of Eslamian10 cannot be compared with
the present study as different methods were suggested for
different types of brackets. This study has been done to evaluate
the effect of conventional debonding technique (the use of
debonding plier) on slot width and interwing distance of the
brackets.
DISCUSSION
Change in Slot Width
Scanning through the literature shows that studies have been
done to describe the effects of several conventional methods of
debonding on tooth surface and/or on bracket. A number of
studies3-5 have been done to describe the effects of conventional
debonding techniques on the tooth surface. Bennett et al in
1984,4 compared three techniques of bond removal and they
concluded that the techniques of applying force to the outer
wings of bracket at the resin bracket interface was the best as
compared to the technique which removed bracket at enamel
resin interface. Odegaard and Segner 1988 6 said that
orthodontists want to remove the appliance at the end of
treatment without exerting excessive forces. An extensive study
was done by Oliver and Pal7 to evaluate the changes in slot size
and interwing distance due to conventional debonding
techniques. Oliver and Pal, in 1989, debonded 821 brackets
from 98 subjects by using three different methods: (i) Mesial
and distal winges of an edgewise twin brackets were squeezed
together with pliers or by placing the pliers occlusally and
gingivally; (ii) blades of the debonding pliers or ligature cutters
positioned at the enamel/composite or composite/bracket
interface; (iii) use of lift off debracketing instrument (LODI).
They found least distortion of brackets by the use of LODI.
Coley Smith A, Rock WP8 also recommended the use of LODI.
Coley Smith suggested the use of archwire into the slot at the
time of debonding to reduce distortion particularly when
After debonding by conventional debonding technique, the
mean decrease in the slot widths of the brackets of groups 1, 2
and 3 were 0.049, 0.033 and 0.027 mm respectively (Table 1).
In group 1, the value of mean difference of 0.049 mm was mainly
because of gross distortion of bracket no. 6. Distortion of other
brackets of group 1 (mean decrease in slot width of the rest of
9 brackets was 0.031 mm) was comparative to those of other
groups. The results of this study cannot be compared fully with
the results of the study of Oliver and Pal because they did not
standardize instrument or technique to debond brackets in
method A and B. Only the group 3 of the present study was
compared with method C. With method C, there was increase
in slot width by 0.016 mm and 0.001 to 0.005 mm in Rocky
mountain bioprogressive brackets and unitek light square
brackets respectively, when maxillary lateral incisor brackets
and mandibular incisor brackets were studied. There was
decrease in slot width by 0.052 mm (RM brackets) when
maxillary central incisors were studied. In group 3 (present
study), there was decrease in slot width by 0.027 mm. The
investigator experienced a considerable heavier force to debond
the brackets of group 1 than the brackets of groups 2 and 3.
Among the three debonding techniques, the slot width got
affected minimally when the brackets were deboned by holding
them gingivoocclusally with archwire into the slot and rotate it
gingivoocclusally.
Table 1: Slot width before bonding, after debonding and comparison
Slot width (in mm)
N
Mean
Std. deviation
Std. error
95% confidence interval
LB
UB
Group 1
Group 2
Group 3
10
10
10
0.049
0.033
0.027
0.058
0.009
0.005
0.018
0.003
0.002
0.008
0.026
0.023
Total
30
0.036
0.034
0.006
0.024
Minimum
Maximum
0.090
0.039
0.031
0.008
0.017
0.021
0.210
0.049
0.038
0.049
0.008
0.210
Kruskal-Wallis ANOVA; p = 0.198; not significant
Table 2: Interwing distance on ‘A’ side before bonding, after debonding and comparison
Interwing A (in mm)
N
Mean
Std. deviation
Std. error
95% confidence interval
LB
UB
Minimum
Maximum
Group 1
Group 2
Group 3
10
10
10
0.051
0.013
0.013
0.060
0.010
0.009
0.019
0.003
0.003
0.008
0.006
0.006
0.094
0.020
0.019
0.005
0.001
0.002
0.214
0.032
0.029
Total
30
0.026
0.039
0.007
0.011
0.040
0.001
0.214
Kruskal-Wallis ANOVA; p = 0.011; significant
The Journal of Indian Orthodontic Society, October-December 2013;47(4):207-210
209
Yogesh Gupta et al
Table 3: Interwing distance on ‘B’ side before bonding, after debonding and comparison
Distance B (in mm)
N
Mean
Std. deviation
Std. error
95% confidence interval
LB
UB
Minimum
Maximum
Group 1
Group 2
Group 3
10
10
10
0.035
0.015
0.012
0.033
0.008
0.011
0.010
0.003
0.004
0.011
0.009
0.004
0.059
0.021
0.020
0.000
0.000
0.000
0.090
0.029
0.028
Total
30
0.021
0.023
0.004
0.012
0.029
0.000
0.090
Kruskal-Wallis ANOVA; p = 0.378; not significant
Change in Interwing Distance on Occlusal Side
The maximum decrease in mean interwing distance was
0.061 mm in group 1, when the brackets were debonded by
holding them mesiodistally and rotating in anticlockwise
direction (Table 2). The decrease in interwing distances in
groups 2 and 3 did not differ much with one another (0.019 and
0.019 mm respectively). Statistically only subgroup 1 was found
different from all other three subgroups.
Change in Interwing Distance on Gingival Side
The decrease in mean interwing distance after debonding was
maximum when the brackets were held mesiodistally and
debonded by rotating them in anticlockwise direction (Table 3).
There was not much difference in mean changes when groups
2 and 3 were compared (0.015 and 0.012 mm respectively).
When the brackets were held mesiodistally, the wings of
each single bracket of a twin bracket came close together without
changing slot width while in the cases when the brackets were
held occlusogingivally, the wings on gingival side came close
to those on occlusal side affecting slot width only without
changing interwing distance.
Mean and standard deviation for the slot width and distance
B was calculated. Data was checked for normality using
Shapiro-Wilks test. Data did not follow the assumptions of
normality. Thus nonparametric test, i.e. Kruskal-Wallis analysis
of variance (ANOVA) was used to test the mean between the
three groups.
Post hoc comparison was done using Mann-Whitney U test
(Table 4). Bonferroni correction was done for the three
comparisons. Thus, Bonferroni corrected alpha value was
0.0167. SPSS version 18.0 was used for statistical analysis.
CONCLUSION
After the active orthodontic treatment, the brackets are removed
by various debonding techniques. The brackets can be reused
after recycling (provided they do not get distorted significantly),
although there may be some objection to their use on ethical
grounds.1 Among conventional debonding techniques (with
bracket removing plier), the best method found was to debond
210
Table 4: Post hoc analysis
Group 1
Group 1
Group 2
Group 3
0.014
0.007
Group 2
Group 3
Sig.
Sig.
Not sig.
0.82
Bonferroni corrected  = 0.0167 (0.05/3)
bracket by holding it occlusogingivally with the archwire into
the slot.
ACKNOWLEDGMENT
The authors thank Dr Puneet Gupta for his help in preparing
this article.
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