Download Chromosome Arch : A Non-invasive Anchorage Device

CASE REPORT
Chromosome Arch: A Non-invasive Anchorage Device
1
Amarnath B.C.1, Roopak Mathw David1, Sakthi Priya. K.R. , Shiva Prasad Gaonkar1
Sanjay Abraham1, Garima Chitkara1
1. Department of Orthodontics and
Dentofacial Orthopaedics
DAPM, R.V. Dental College
Bangalore, Karnataka, India
ABSTRACT
Anchorage is an important consideration when planning orthodontic tooth movement.
Unwanted tooth movement known as loss of anchorage can have a detrimental effect on the
treatment outcome. Anchorage can be sourced from the teeth, the oral mucosa and underlying
bone, implants and extra orally. The aim of this case report was to illustrate differences between
the outcomes of treatment using chromosome arch and conventional Transpalatal arch
anchorage in bimaxillary protrusion patients.
Key words: Anchorage, Chromosome arch, Transpalatal arch.
JOURNAL OF DENTAL SCIENCES AND RESEARCH
Vol. 4, Issue 2, Pages 10 - 20
INTRODUCTION:
FABRICATION OF CHROMOSOME ARCH:
Anchorage is defined as the resistance to unwanted tooth
movement[1]. Control of anchorage is one of the most
important aspects of orthodontics. Conventional
methods of reinforcing orthodontic anchorage like
Transpalatal arch[2], Double Transpalatal arch, Nance
button, Intraoral intermaxillary elastics[3], Headgears[4]
etc, have certain practical limitations, including
complicated appliance design, produce unwanted
reciprocal effects, and neccessitates exceptional
patient cooperation. Newer anchorage devices like
microimplants[5] though provide excellent sites of force
delivery without taxing anchorage, have the
disadvantages of invasiveness and is expensive.
Chromosome arch was designed by Dr. Esequiel
Eduardo Rodriguez Yanez6. It is made with 0.036” round
stainless steel wire in an “X” manner and it is cemented to
first and second maxillary molars. In its basic design the
chromosome arch has two distal palatal bends (one on
each side) to aid during canine and anterior segment
retraction, diminishing unwanted tooth movement.
The chromosome arch is a simple, effective and versatile
means of controlling anchorage. This case report
illustrates the outcomes of treatment of two cases treated
using chromosome arch and conventional Transpalatal
arch anchorage in bimaxillary protrusion patients.
Address for correspondence:
Dr. Amarnath B.C.
E-mail: [email protected]
Access this article online
Website: http://www.ssdctumkur.org/jdsr.php
10
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Yes
Steps in fabrication:
1. Wire bending with the hollow chopped plier in the
middle of the wire. (Fig 1)
2. After the bend is done the wire is adapted to the
palatal vault. (Fig 2)
3. Once adapted to the palatine vault the center of
resistance of the molars is marked and distal bends
are made. (Fig 3)
4. The distal bends are made and the end of the wire is
adapted to the palatal aspect of the second molars.
(Fig 4)
5. A second wire is bent in the middle and the ends are
adapted to the palatal aspects of upper first molars.
These two wires are placed together and soldered.
(Fig 5 and 6)
Vol. 4, Issue 2, September 2013
6. Soldered chromosome arch on working model.
(Fig 7) (chromosome arch can be either bonded or
soldered to the molar bands).
The versatility of the appliance lies in the fact that, it can
provide anchorage in all the three planes of space by
merely adding few wire components and thereby
effecting multiple tooth movements simulta neously.
The following are cases treated at Department of
Orthodontics, DAPM R V Dental College which
illustrates the advantages of Chromosome arch (case
report 1) over the Transpalatal arch (case report 2).
After first premolar extractions, MBT pre-adjusted
appliances (Unitek Gemini, 3M Unitek, Monrovia,
California, USA) were fixed. En-masse retraction of the
anterior arch segment was carried out.
CASE REPORT 1: EN-MASSE RETRACTION
USING CHROMOSOME ARCH FOR
ANCHORAGE REINFORCEMENT
A 15-year-old female patient presented with a chief
complaint of forwardly placed upper front teeth. The
extraoral findings of the patient revealed increase in
lower facial proportion, incisor exposure of 4mm,
incompetent lips, convex profile. Intraorally, she had
Angle's Class I molar and class I canine relation with
proclined anteriors, increased overjet and overbite.
The cephalometric analysis revealed a Class II skeletal
relationship (SNA- 84° SNB- 80°, and ANB-4°) on
Fig 1
Fig 2
Fig 5
account of prognathic maxilla and an average
mandibular plane angle of (MPA=30°). The upper and
lower incisors were proclined with an acute interincisal
angle (92°) (Table 1). Soft tissue analysis revealed an
acute nasolabial angle and lip strain.
DIAGNOSIS:
Angle's class I molar relation on a mild class II skeletal
jaw base with average growth pattern. She had a Class I
canine relation and proclined upper and lower incisors,
with mild crowding in lower anteriors with acute
nasolabial angle and lip strain of 2 mm.
TREATMENT OBJECTIVES:
(1) Maintain Class I molar and canine relationships and
obtain normal overbite and overjet.
(2) Alignment of upper and lower arch.
(3) Correcting the axial inclination of upper and lower
anteriors
(4) Reduce protrusion of the upper and lower lips and
obtain soft tissue harmony.
TREATMENT PLAN:
Considering the patient's chief complaint, proclination
of upper and lower incisors, acute nasolabial angle, it was
decided to treat this case with extraction of all the first
premolars with maximum anchorage and utilize this
Fig 3
Fig 6
Fig 4
Fig 7
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Journal of Dental Sciences and Research
space for retraction of proclined incisors. Considering all
the above mentioned, the treatment plan was formulated
as follows:
1. General dental care
and second molars on both sides. Lingual arch was
used in the lower arch.
4. Appliance plan: MBT 0.022” slot PEA.
5. Decrowding and Anterior retraction
2. Extraction therapy: Relieve crowding in lower
anteriors. Upper and lower anterior teeth retraction
to relieve lip strain and correct axial inclination of the
anteriors.
3. Anchorage plan: Anchorage was reinforced in the
upper arch using chromosome arch including first
6. Finishing & detailing
7. Retention plan: Fixed retainers in lower arch and
removable retainer in the upper arch.
Treatment duration was two years and four months.
Fig 8: Pre treatment extraoral photographs
Fig 9: Pre treatment intraoral photographs
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Vol. 4, Issue 2, September 2013
Fig 10: Pre treatment lateral cephalogram and OPG
Fig11 - Retraction using sliding mechanics with anchorage reinforcement using chromosome arch
TREATMENT RESULTS :
Class I canine and molar relationship were maintained
and normal overbite and overjet was established, with
good interdigitation of the posterior teeth. Significant
retraction of the upper and lower incisors was achieved
with no anchor loss, both of which improved the patient's
nasolabial angle and lip posture. Extra oral photographs
and soft tissue cephalometric analysis revealed a
harmonious facial profile with a normal nasolabial angle
and lip posture.
The superimposition shows
Ø
No loss of anchorage in upper and lower arch in
sagittal plane .
Ø
There is no change in the facial axis angle.
Ø
There is retraction of both upper and lower anteriors
with no extrusion of upper and lower molars.
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Journal of Dental Sciences and Research
Fig 12: Post treatment extraoral photographs
Fig 13: Post treatment intraoral photographs
Table 1: Cephalometric Analysis before and after treatment
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VALUES
Pre Rx
Post Rx
SNA
78°
79°
SNB
73°
76°
ANB
5°
3°
Upper incisor to NA
43°
18°
Lower incisor to NB
38°
28°
Inter-Incisal Angle
92°
124°
GoGn-Sn
30°
32°
Nasolabial Angle
81°
96°
Face ht. ratio
64.5%
65.6%
Vol. 4, Issue 2, September 2013
Fig 14: Pre finishing lateral cephalogram and post treatment OPG
CASE REPORT 2: EN-MASSE RETRACTION
U S I N G T R A N S PA L ATA L A R C H F O R
ANCHORAGE REINFORCEMENT
A 19-year-old female patient presented with a chief
complaint of forwardly placed upper front teeth. The
extraoral findings of the patient revealed increase in
lower facial proportion, incisor exposure of 4mm,
incompetent lips, convex profile. Intraorally, she had
Angle's Class I molar and class I canine relation with
proclined anteriors.
The cephalometric analysis revealed a Class I skeletal
relationship (SNA- 82.50, SNB- 790, and ANB-2.50)
and an average mandibular plane angle of (MPA=34°).
The upper and lower incisors were proclined with an
acute interincisal angle (106°).(Table-2) Soft tissue
analysis revealed an acute nasolabial angle and lip strain.
(3) Correcting the axial inclination of upper and lower
anteriors
(4) Reduce protrusion of the upper and lower lips and
obtain soft tissue harmony.
TREATMENT PLAN: Considering the patient's chief
complaint, proclination of upper and lower incisors,
acute nasolabial angle, it was decided to treat this case
with extraction of all the first premolars with maximum
anchorage and utilize this space for retraction of
proclined incisors. Considering all the above mentioned,
the treatment plan was formulated as follows:
1.
General dental care
2.
Extraction therapy: Upper and lower anterior teeth
retraction to relieve lip strain and correct axial
inclination of the anteriors.
3.
Anchorage plan: Anchorage was reinforced in the
upper arch using transpalatal arch. Lingual arch was
used in the lower arch.
4.
Appliance plan: MBT 0.022” slot PEA.
5.
Anterior retraction
TREATMENT OBJECTIVES:
6.
Finishing & detailing
(1) Maintain Class I molar and canine relationships and
obtain normal overbite and overjet.
7.
Retention plan: Fixed retainers in lower arch and
removable retainer in the upper arch.
(2) Alignment of upper and lower arch.
Treatment duration was three years
DIAGNOSIS:
Angle's class I molar relation on a class I skeletal jaw
base with average growth pattern. She had a class I canine
relation and proclined upper and lower incisors with
acute nasolabial angle and lip strain of 4 mm.
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Journal of Dental Sciences and Research
Fig 15: Pre treatment extraoral photographs
Fig 16: Pre treatment intraoral photographs
Fig 17: Pre treatment lateral Cephalogram and OPG
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Vol. 4, Issue 2, September 2013
Fig 18: Sliding mechanics with anchorage reinforcement using transpalatal arch
TREATMENT RESULTS ACHIEVED
Class I canine and molar relationship were maintained
and normal overbite and overjet was established, with
good interdigitation of the posterior teeth. Significant
retraction of the upper and lower incisors was achieved
with two mm anchor loss due to mesial movement of
upper molars and two mm extrusion of upper molars were
noted. There was an improvement of patient's nasolabial
angle and lip posture. Extra oral photographs and soft
tissue cephalometric analysis revealed a harmonious
facial profile with a normal nasolabial angle and lip
posture.
Ø
There is no change in the facial axis angle.
Ø
There is retraction of both upper anteriors with two
mm extrusion of upper molars.
The superimposition shows
Ø
Loss of anchorage in upper and lower arch by 2 mm
mesial movement of upper and lower molars.
Ø
There is no change in the facial axis angle.
Ø
There is retraction of both upper anteriors with 2 mm
extrusion of upper molars.
The superimposition shows
Ø
Loss of anchorage in upper and lower arch by two
mm mesial movement of upper and lower molars.
Fig 19: Post treatment extraoral photographs
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Journal of Dental Sciences and Research
Fig 20: Post treatment intraoral photographs
Fig 21: Pre finishing lateral cephalogram and OPG
TABLE 2: CEPHALOMETRIC ANALYSIS BEFORE AND AFTER TREATMENT
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VALUES
Pre Rx
Post Rx
SNA
82.5°
79°
SNB
79°
77°
ANB
2.5°
2°
Upper incisor to NA
36°
27°
Lower incisor to NB
34°
22°
Inter-Incisal Angle
106°
130°
GoGn-Sn
34°
34°
Nasolabial Angle
80°
97°
Face ht. ratio
57%
58.4%
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DISCUSSION:
The orthodontic tooth movement is greatly influenced by
the characteristics of the applied force, including its
magnitude, direction, moment to force ratio and the
physiological condition of the periodontal tissue of
individual patients[12]. The characteristics of applied
force also depends on the orthodontic appliance used[1].
The purpose of this case report is to illustrate the
advantages of chromosome arch as an anchorage device
over the transpalatal arch, which is routinely used in
clinical practice.
The superimposition using chromosome arch as an
anchorage device showed, no loss of anchorage in upper
arch in sagittal and vertical plane with retraction of upper
anteriors. The superimposition using transpalatal arch as
an anchorage device showed 2 mm of extrusion and 2 mm
of mesial movement of upper molars, suggestive of
anchor loss along with retraction of upper anteriors.
When compared with conventional transpalatal
anchorage, chromosome arch results in more retraction
of the maxillary incisors and more lingual inclination of
the mandibular incisors, and may also counteract
clockwise rotation of the mandibular and occlusal
planes, during MBT treatment for bimaxillary protrusion
in young adults.
Sliding mechanics with chromosome arch provided
better control in sagittal and vertical plane compared to
transpalatal arch and may provide absolute anchorage
and could control mandibular rotation.
SUPERIMPOSITION OF CASE REPORT 1:
SUPERIMPOSITION OF CASE REPORT 2:
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Journal of Dental Sciences and Research
COMPARISON OF SUPERIMPOSITIONS:
Chromosome arch
Transpalatal arch
Facial axis angle
No change
No change
nchor loss (mesial movement of molars)
No anchor loss
2mm anchor loss
Extrusion of upper molars
No extrusion
2mm extrusion seen
Versatility and Advantages of chromosome arch:[18]
2.
1. Excellent maximum anchorage appliance that
includes a greater number of teeth to the anchorage
unit.
3.
2. This device can be used along with other auxiliaries
for affecting multiple tooth movements without
taxing the anchorage.
3. Provides problem based design for force application.
4.
5.
4. The retraction movement is done in a more bodily
fashion, with no undesired rotations and less time.
5. Any four teeth can be used for anchorage, provides
greater control in all three plane
6.
6. It is a non invasive, inexpensive device which is easy
to fabricate.
7.
7. The chromosome arch can be soldered to the molar
bands or directly bonded to the molars.
8.
8. Multiple tooth movement, like individual canine
retraction, disimpaction, decrowding, cross bite
correction can be carried out during initial stages of
treatment itself.
CONCLUSION:
9.
10.
11.
12.
The maxillary anterior teeth were retracted without any
loss of anchorage in sagittal plane in case 1 with the aid of
chromosome arch and 2mm anchor loss is seen in case 2
using transpalatal arch as an anchorage device. In
vertical plane in case 1 using chromosome arch, no
extrusion of molars was seen while using transpalatal
arch as an anchorage device there was an extrusion of
upper molars by 2mm.
Thus the chromosome arch provides an anchorage
control better than conventional transpalatal arch.
Chromosome arch is an effective, non invasive
anchorage device for reinforcing anchorage with PEA. It
provides excellent anchorage control in sagittal and
vertical planes.
References:
1.
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