This document discusses orthodontic archwire selection during the alignment stage of treatment with preadjusted appliances. It provides details on different types of archwires used for alignment including multi-strand stainless steel, conventional and superelastic nickel-titanium (NiTi), and heat-activated NiTi wires. Superelastic NiTi wires are preferred for alignment due to their low stiffness, high springback, and ability to deliver nearly constant light forces during tooth movement. The document discusses various archwire sequences used during alignment and leveling, noting that there is no set sequence but heat-activated NiTi can replace multiple stainless steel wires to reduce visits and discomfort.

1. Selection of orthodontic
preformed archwires
during the alignment stage
of preadjusted fixed
appliance
Mansoura Egypt
Presented by prof dr Maher Fouda
2

2. This lecture was
uploaded on the
slideshare in addition to
several undergraduate
and postgraduate
orthodontic lectures .

3. Stages of Straight Wire
Technique
1. Leveling and aligning.
2. Overbite reduction.
3. Overjet reduction and
space closure.
4. Finishing and occlusal
detailing.

4. Let us take into
our consideration
the following
important points :

5. Point 1: alignment is
the lining
up of teeth of an arch in
order to achieve normal
contact point
relationships.

6. Round flexible
archwires are
needed to provide a
gentle continuous
force that is flexible
enough to engage
the
brackets on the
misaligned teeth .
What is needed in this stage

7. The first
Ni–Ti archwire, marketed as
Nitinol (Unitek Corp.) in the
late 60s, stood out for its
low stiffness and high
springback properties
that define conventional
Ni–Ti archwires.
springback (tendancy of the wire to revert to
its original form)
stiffness(resisting deformation in response to
applied force)
stood out (noticable)

8. The Nitinol alloy was
developed by William F
Buehler, a research
metallurgist at Naval
Ordinance Laboratory in the
year 1960 after which Dr.
George
Andreason introduced it in
orthodontics where it
brought about
a revolutionary change .

9. According to Kusy ,
there are three
categories of
Ni–Ti archwires:
1-conventional,
2-pseudoelastic or
superelastic and
3-thermoplastic
wires, the last two
of these are
superelastic.

10. Since then, the
Ni–Ti wire has
rapidly become
the wire of choice
for the alignment
and levelling
treatment stage.

11. The initially
discovered
nitinol was a
Martensitic
stabilized alloy
which showed
no
superelasticity
Martensitic (very hard form of
steel crystaline structure)

12. Nitinol Classic
Archwire is
developed as an
alternative to
stainless steel
archwires.
It has long working
range.
It posess 40% the
forces of stainless
steel

13. Nitinol has excellent springback property but it does not
possess shape memory or super elasticity as it was
manufactured by a work hardening process.. It is available as
NiTi; Nitinol, Orthonol, Sentinol and Titanol.

14. The success of
today’s Ni–Ti
archwires is
due to their
superelasticity
and shape
memory. Superelastic NiTi 0.014-inch during initial
alignment orthodontic stage, before (left) and
after (right) bracket engagement. Note the
degree of misalignment that the wire can
tolerate due to superelastic properties.

15. An ideal archwire
should be able to
move teeth with a
light, continuous
force. This force
should be designed
to minimize patient
discomfort, tissue
hyalinization and
root resorption.
Examples of dimples and stops
placed on orthodontic archwires to
prevent the wires from excessive
sliding along the dental arch.
NiTi arch wire used for alignment
and leveling

16. When a force is
applied, the
archwire
should behave
elastically over
a period of
weeks to
months.
.
a 0.014-in round NiTi wire (natural
arch form) , Nickel-Titanium Archwire) was
applied as the initial archwire
immediately after the bonding procedure.

17. When the nitinol
archwire is activated
over a considerable
range of deflection, the
force produced remains
essentially constant.
This means that the
archwire would exert
the same amount of
force whether deflected
over a small or large
distance.
Maxillary arch during initial alignment
orthodontic
stage. Superelastic NiTi 0.012-inch (a)
before and (b) after bracket
engagement. Note the degree of the
misalignment which the wire
can tolerate due to its superelastic
properties.

18. This is an
extremely
desirable
property because
very low and
constant forces
for tooth
movement are
provided by the
archwire during
tooth movement.
Banding and bonding (upper and lower
preadjusted edgewise fixed appliances with
MBT prescription and 0:022″ × 0:028″ slot size
bracket) and placement of the initial leveling
and aligning archwires (0.014 superelastic
nickel titanium).
Published 29 April 2022

19. Point 2 : superelastic
NitT is better than
conventional Nitinol
wire is that engagement
of the displaced tooth is
readily achievable

20. Point 3 :The most common
archwires used to align teeth
are multistrand stainless
steel, superelastic NiTi and
heat activated NiTi or thermal
activated NiTi.

21. Point 4 : Multi-Strand
Stainless Steel archwires
have low stiffness and
can be used for initial
leveling and aligning
stage in orthodontics.

22. Point 5-However, due to
their lower elastic limit they
can be readily deformed if
acted upon by any other
force such as food chewing.
Elastic limit refers to the maximum value of
force for which a material shows elastic
behaviors.

23. Multi-Strand Archwires or Twist
flex or Triple flex
3-strand wires are three
twisted strands of fine, round
stainless steel that form a
single wire to provide light
force, good flexibility, and
resiliency.

24. It has been reported that some
nickel titanium wires appeared to
be no more effective than a multi-
stranded, inexpensive stainless
steel wire, as, for example, a small
diameter (.014") superelastic nickel
titanium compared to a .015"
multi-stranded stainless steel wire.
The conclusions from clinical
observations were that the less
expensive multi-stranded wire was
just as efficient as .014" nickel
titanium wire.

25. Point 6 : NiTi could
replace multistrand
arch wires in the
alignment stage

26. The introduction of
nickel-titanium
wires provided a
possible
substitute for
multistrand and
steel round wires
during the
leveling and aligning
stages of treatment.
A .014 nickel‐titanium arch wire was placed
on the
maxillary arch
multistrand and steel round wires

27. Nickel-titanium
(NiTi) wires are
preferred by
clinicians because
compared to
stainless steel
wires, they have a
wider working
range and higher
springback
properties.
Maxillary and mandibular
.016 nickel‐titanium
arch wires have been placed.
A sectional .016 × .022
β‐titanium
wire was placed on the
maxillary right molar to
canine for
retraction of the canine.
Why Nickel Titanium is preferred by clinicians

28. POINT 7 : One nickel
titanium
wire could be used in
place of approximately
two sizes of
stainless steel wires.

29. Archwire sequence for the standard edgewise appliance
CASE REPORT

31. full cusp Class II molar
Bonding was done
using a standard
edgewise appliance
of slot size 0.022” ×
0.028”, followed by
levelling and
alignment using
0.014” stainless
steel (SS) multiple
loop archwire.
CASE REPORT

32. full cusp Class II molar
After that, series of
gradually increased
dimension archwires
from 0.016” to 0.018”
× 0.025” SS were
made with the first
and second order
bends, molar stops
with accentuated
curve of Spee for bite
opening

33. full cusp Class II molar
At the end of 6 months,
canines were retracted in
upper arch by using 150 g, 9
mm nickel titanium close coil
spring to reduce the size of
anterior retracting unit. A
0.019” × 0.025” SS retraction
archwire was made without
molar stops and accentuated
curve of Spee and ligated in
upper and lower arch. Class II
elastics were used to retract
the upper incisor and
mesialize the lower molars

34. Archwire sequence for the straight wire appliance
Class I dental and skeletal Class II

35. Archwire sequence for the straight wire appliance
All teeth except the ectopic
canines were
bonded. The incisors were
aligned with segmental
mechanics on .014" and
.016" nickel titanium
archwires,
and the canines were
allowed to drift into
the extraction spaces
without any direct force
application
Sequential drifting of canines after
one (A), three (B), and five (C) months
of treatment with
MBT* fixed appliances, transpalatal
arch, and nickel titanium archwires.
CASE REPORT

36. Archwire sequence for the straight wire appliance
After five months of
treatment, the canines
had erupted into
position, and a
continuous .016"
nickel titanium archwire
was placed. Leveling was
completed using .016" ×
.022" nickel titanium and
.016" × .022" and .017" ×
.025" stainless steel
archwires.
A. Patient after 18
months of treatment.
CASE REPORT

37. Archwire sequence for the straight wire appliance
A. Patient after 18
months of treatment.
Space closure was
accomplished with sliding
mechanics on .019" × .025"
stainless steel
archwires. Finishing, detailing,
and settling were
carried out using .014"
stainless steel archwires
and red elastics (3⁄16",
3.5oz).
CASE REPORT

38. Point 8 : It is not
advisable to use NiTi
archwires from different
brands on the same
patient as the size may
vary by brand.

39. Preformed upper NiTi archwires with different
brands and different intercanine distances
Preformed lower NiTi archwires with different
brands and different intercanine distances

40. different archwires brands

41. Point 9 :
superelastic NiTi archwires
deliver a nearly light
constant force over a span
of activations—ideally those
that occur between office
visits and rapid tooth
movement results

42. Point 10 :
Superelastic Niti wire
causes more
discomfort for the
patient comparing to
heat activated Niti.

43. Point 11 : Heat activated
wires could be used as a
substitute for three of the
traditional stainless steel
wires in certain situations,
which was a significant
improvement.

44. Point 11 : Niti Heat-Activated
wire is a thermally activated
super-elastic archwire.
It is the easiest of Nitinol wires
to engage, and it delivers light
continuous
forces that effectively move
teeth with minimal discomfort
to the patient.

45. heat-
activated/thermal
NiTi wires are soft
and pliable at
room temperature,
which permits
easier insertion
into the bracket
slots. As the wire
warms to mouth
temperature, the
wire becomes
more “active.”

46. TEXTBOOK OF ORTHODONTICS
The wire is cooled down with
the help of a refrigerant spray
or ice bath before insertion to
make it flexible and the oral
environment raises the
temperature of the deformed
archwire which returns to the
starting shape thereby
aligning the crowded arch .

47. Apply Freeze Spray
Coolant directly onto
the archwire or spray
onto a swab and apply
to the archwire. For
maximum effect, wrap
the archwire in gauze
and saturate the gauze
with Freeze Spray
Coolant

48. Niti Ice Instrument
Fill the NiTi Ice
Instrument with
water and freeze.
The light weight
compact design
allows for pin-
point activation
of thermal nickel
titanium
archwires
• For selective chilling of the NiTi archwire
• Makes the archwire soft and flexible so
that it can be inserted easily

49. Instead of replacing
wires on a per visit basis
during leveling and
aligning, a coolant could
be applied to the heat-
activated nickel-titanium
(HAN'T) wire in the areas
where full bracket
engagement had not
been achieved, and the
wire could be retied for
complete engagement.
initial .016 HANT wire was
followed by a rectangular HANT
wire and then a .019/.025
rectangular steel wire.
MBT

50. The normal warmth
of the oral cavity
produced significant
activation of the wire-
and very efficient
tooth movement.
Surprisingly, patients
did not seem to
complain of added
discomfort, probably
because of the light
forces that were
introduced.
Rectangular HANT
wires are very
effective in
achieving tooth
movements of this
type in this region.
They give good
control and do not
distort in response
to masticatory
forces
MBT

51. Forms and diameters of Orthodontic Niti heat
- activated arch wire
initial .016 HANT wire was followed by a
rectangular HANT wire

52. every
clinician is
different
and has
their own
preferred
archwire
sequence.

53. The next
archwire
cannot be
placed
until the
previous
archwire has
been engaged
to all the
teeth.

54. Point 12 :Archwire
sequence with standard
edgewise appliance used
stainless steel for
alignment ; case report :

55. Treatment involved the
extraction of first
premolars in the upper
and lower arch to
correct the
proclination and
maintain angle’s Class-I
molar relation.
Treatment started with
the placement of
0.022Ë•
standard
edgewise brackets and
molar tubes.
Angles Class I molar and canine relation
Treatment began with the leveling and
alignment with well-coordinated 0.016Ë•
and
0.018Ë •
stainless steel (S.S.) arch wires

56. Treatment began
with the leveling
and alignment with
well-coordinated
0.016Ë•
and
0.018Ë •
stainless
steel (S.S.) arch
wires with molar
stops, progressive
tip back bends and
curve of spee wire in
the upper and
reverse curve of
spee wire in the
lower arch .
Angles Class I molar and canine relation

57. Individual canine
retraction was
started and
finished with an
elastic chain on
0.018” stainless
steel wire with tip
backs. Care was
taken to put a light
force to avoid
tipping of canine
Angles Class I molar and canine relation,

58. After canine retraction,
0.019 × 0.025Ë•
S.S. T loop
archwires with
progressive tip back bends
were placed in both
arches . Progressive buccal
root torque was placed in
the lower posterior
segment, progressive
lingual root torque in the
upper posterior segment
and lingual root torque in
the upper and lower
anterior segment.
Angles Class I molar and canine relation,

59. Patient was recalled
every 6 weeks for
reactivation of loops
and to check the
progress. Finishing
was performed on
0.016x0.022” S.S.
archwires with tip
backs and artistic
positioning bends
Angles Class I molar and canine relation,

60. Point 13 :
There is no certain arch
wire sequence that
clinicians have to go
by.

61. Point 14: Archwires
sequence with the
preadjusted fixed
applaince ; case
reports:

62. Sizes used in this stage of
treatment:
●● 0.012 in., considered in very
crowded cases
●● 0.013 in., considered in very
crowded cases
●● 0.014 in.
●● 0.016 in., considered if unable
to engage 0.018 in.
●● 0.018 in.
Examples of archwire sequence

64. Morelli Intraoral Orthodontic
Archwire Super Elastic NiTi

66. alignment in the maxillary and
mandibular dental arches was
achieved by a 0.016-in thermal
nickel-titanium wire. In the
mandibular arch, the space
closure started with lacebacks
on the right and left sides .
Then, leveling was obtained in
both arches with 0.019 x
0.025-in thermal nickel
titanium wires. Maxillary and
mandibular 0.019 x 0.025-in
stainless steel rectangular
archwires and power chain
were used to close the
extraction spaces .
archwire sequence CASE REPORT
alignment was achieved by a 0.016-in thermal
nickel-titanium wire
leveling was obtained with 0.019 x 0.025-in
thermal nickel titanium wires
0.019 x 0.025-in stainless steel rectangular
archwires and power chain were used to close
the extraction spaces .

67. After the initial wire,
0.014 NiTi, 0.016
NiTi, followed by
0.016×0.022” NiTi
wire were placed for
the sequential
leveling. Stainless
steel wire of
016×022” in upper
and lower arch was
used for final
leveling.
ARCH WIRES SEQUENCE
Alignment and leveling was done with, 0.014
NiTi, 0.016 NiTi, followed by 0.016×0.022”
NiTi and finally 16x22 st st

68. orthodontic treatment
was initiated with a 022
MBT appliance and 0.16
heat activated (HA)
nickel-titanium (NiTi)
archwires. After 20 weeks,
rectangular 19 × 25 HA NiTi
archwires were placed for
further alignment and
leveling. Initial space
closure carried out with
rectangular stainless steel
(SS) wires with loops
Archwires sequence
Alignment was done with 0.16 heat activated
(HA) nickel-titanium (NiTi) archwires and
rectangular 19 × 25 HA NiTi archwires
Initial space closure carried out with
rectangular stainless steel (SS) wires with
loops

69. The alignment and the leveling phases were performed using
the following sequence: 0.014- and 0.016-in nickel titanium
arches, and 0.018- and 0.020-in stainless steel arches
The distalization of the canines was performed using the
0.020-in stainless steel archwire
Distalization rate of maxillary canines in an alveolus filled
with leukocyte-platelet–rich fibrin in adults:
A randomized controlled clinical split-mouth trial
Case report
ARCH WIRES SEQUENCE

70. class I molar relationship bilaterally, missing
left maxillary lateral incisor, upper right peg
lateral incisor, and gap between the teeth in
the upper front region
ARCH WIRES SEQUENCE

71. 0.018″ ss wire followed
by 0:019 × 0:025″ ss wire
was placed to level and
express the prescription
of the bracket
ARCH WIRES SEQUENCE
The arches were
aligned using the
following sequence of
archwires: 0.014″ NiTi
and 0.016″ NiTi

72. Leveling and alignment
were started on maxillo-
mandibular dentition with
the use of 0.014-inch nickel-
titanium wire. After
completion initial
alignment, the wires
replaced into 0.016×0.022
stainless steel archwires
and upper and lower
canines on both sides were
started to retract with
elastic chains. Then,
0.016×0.022-inch stainless
steel wires were used for an
anterior retraction phase
Leveling and alignment were with the use of
0.014-inch nickel-titanium wire then 16x22 st
st for retraction

73. The archwire sequence shown has been
employed by the MBT. It has significantly reduced
chairside time and increased the efficiency of tooth
movement, owing the minimizing of permanent
archwire deflection .
The MBT system ARCHWIRE SEQUENCE

74. MBT prescription for tip and torque
Archwires sequence
The MBT system
Initial aligning
.014 or .016 heat-activated nickel
titanium
Leveling
.019 x .025 heat-activated nickel
titanium
Working
.019 x .025 stainless steel with hooks
Finishing
.019 x .025 beta titanium
Settling
.019 x .025 braided stainless steeL

75. Lower force than solid stainless steel archwires
8-Braid wires are made of eight fine, equal-sized
wires braided tightly and rolled to the most popular
square and rectangle wire sizes. 8-Braid Stainless
Steel archwires combine low tooth-moving forces
with high resiliency. Great for aligning and finishing.
Resists fraying when cut.

76. ARCHWIRE SEQUENCE Case report
Class I incisor, canine and molar relationship
bilaterally with an average overjet and
overbite and proclined and forwardly placed
upper and lower anterior teeth.
Complete bonding &
banding in both maxillary
and mandibular arch was
done, using MBT-
0.022X0.028”slot. Initially a
0.012” NiTi wire was used
which was followed by
0.014 , 0.016”, 0.018”,
0.020” Niti archwires
following sequence A of
MBT.

77. ARCHWIRE SEQUENCE Case report
Class I incisor, canine and molar relationship
bilaterally with an average overjet and
overbite and proclined and forwardly placed
upper and lower anterior teeth.
After 6 months of
alignment and leveling
NiTi round wires were
discontinued. Retraction
and closure of existing
spaces was then started
by use of 0.019” x 0.025”
rectangular NiTi
followed by 0.019” x
0.025” rectangular
stainless steel wires.

78. ARCHWIRE SEQUENCE Case report
Class I incisor, canine and molar relationship
bilaterally with an average overjet and
overbite and proclined and forwardly placed
upper and lower anterior teeth.
Reverse curve of spee
in the lower arch and
exaggerated curve of
spee in the upper arch
was incorporated in the
heavy archwires to
prevent the excessive
bite deepening during
retraction process.

79. ARCHWIRE SEQUENCE Case report
Class I incisor, canine and molar relationship
bilaterally with an average overjet and
overbite and proclined and forwardly placed
upper and lower anterior teeth.
Retraction and closure
of existing spaces was
done with the help of
Elastomeric chains
delivering light
continuous forces and
replaced after every 4
weeks due to force
decay and reduction in
its activity.

80. ARCHWIRE SEQUENCE Case report
Class I incisor, canine and molar relationship
bilaterally with an average overjet and
overbite and proclined and forwardly placed
upper and lower anterior teeth.
Finally light settling
elastics were given
with rectangular steel
wires in lower arch
and 0.012” light NiTi
wire in upper arch for
settling , finishing,
detailing and proper
interrcuspation.

81. MBT 0.022
preadjusted
appliance was
bonded (ceramic
brackets in
anteriors and
metal brackets in
posteriors)
Case report
ARCHWIRE SEQUENCE
levelling alignment was initiated. Wire
sequence followed was 0.014“ Niti,
0.016” Niti, 0.016x0.022 Niti, 0.017x
0.025 ss, and 0.019x0.025 ss

82. Archwires sequence
Initial leveling and alignment
were performed using a round
0.014-inch nickel-titanium
archwire (NiTi) and canines’
laceback , followed by
0.016-inch NiTi and then 0.016 ×
0.016-inch NiTi
Case report
canine retraction started on 0.016
× 0.022-inch SS archwire using
power chain
After canine retraction, the upper
and lower incisors were leveled and
aligned, and then the midline was
corrected and
were retracted using rectangular SS
0.016 × 0.022-inch SS archwire with
T-loop in both arches that was
activated by cinch back the wire
every 3 weeks.
finishing and detailing using
0.017 × 0.025-inch titanium
molybdenum alloy archwire
(TMA) and 0.017 × 0.025-inch
SS.

83. Archwires sequence
Preadjusted MBT
brackets, slot
0.022 × 0.028-in were
used. Brackets were
firstly placed in the
maxillary arch . Leveling
and alignment was
achieved with 0.014-in,
0.016-in, 0.020-in,
0.017 × 0.025-in, and
0.019 × 0.025-in nickel-
titanium (NiTi)
archwires. Then, a
0.018 × 0.025-in
stainless steel archwire
was placed.

84. Complete bonding &
banding in both
maxillary and
mandibular arch was
done, using MBT-
0.022X0.028”slot.
Initially a 0.012” NiTi
wire was used which
was followed by
0.014 , 0.016”,
0.018”, 0.020” Niti
archwires following
sequence A of MBT.
Case report

85. After 6 months of
alignment and
leveling NiTi round
wires were
discontinued.
Retraction and closure
of existing spaces was
then started by use of
0.019” x 0.025”
rectangular NiTi
followed by 0.019” x
0.025” rectangular
stainless steel wires.
Case report

86. Retraction and closure of
existing spaces was done
with the help of Elastomeric
chains delivering light
continuous forces and
replaced after every 4 weeks
due to force decay and
reduction in its activity.
Finally light settling elastics
were given with rectangular
steel wires in lower arch and
0.012” light NiTi wire in
upper arch for settling .
Case report

87. Point 15 : it is important to
select prefabricated NiTi
archwires that are similar to
the patient arch form to
minimize changes and
reduce possible relapse .

88. Point 16 : It is
generally advised to
maintain the patient
arch
form during fixed
orthodontic treatment.

89. No single
arch form is
unique to
any of the
Angle’s class
of
malocclusion

91. Arch Form
Changes
to arch form
during
treatment
may result in
instability
and
subsequent
relapse

92. Arch Form
With this in mind,
3M provides three
distinct arch forms(
taper , sqaure and
ovoid) that
reconcile the
variation
in anterior
curvature, inter-
cuspid width, inter-
molar width and the
curvature from the
cuspid to the
second molars.

93. Tapered Arch Form:
Among the
three, this arch
form offers the
narrowest
inter-cuspid
width.

94. Tapered Arch Form:
This form is
especially ideal for
patients with
narrow arch forms
and gingival
recession in the
area of the cuspids
and bicuspids
(most frequently
found among
adults).

95. Tapered Arch
Form: Another
useful application
of this arch form
is in cases of
partial treatment
of only one arch,
as it will help
reduce the
occurrence of
expansion in the
treated arch

96. Ovoid Arch Form: With
an inter-cuspid width
between the other two
forms, this form is
intended, when
employed with the
retention and settling
steps , to maintain a
stable arch form post-
treatment.

97. Square Arch
Form: This
arch form is
especially
practical for
patients with
broad natural
arch forms.

98. Square Arch Form:
It can also be
applied early
in treatment in
cases that
require buccal
uprighting of
the lower
posterior
segments and
upper arch
expansion.

99. Square Arch
Form: If over-
expansion
occurs, it is
possible to
change to the
Ovoid arch
forms later in
treatment.

100. Arch Form,
Particularly
the Mandibular
Arch,
Cannot Be
Permanently
Altered with
Appliance
Therapy

101. Treatment
should be
directed
toward
maintaining the
arch form
presented by
the
malocclusion
as much as
possible.

102. In a clinical
situation,
orthodontists
should select the
most appropriate
archwire for the
patient arch form
and treatment
plan to align and
level the teeth.
Selecting the archwire
on the pretreatment
model

103. This selection is
sometimes
neglected as
the
orthodontists
might assume
that light NiTi
archwires will
not alter
archwidth.
Maxillary
archforms.
(A) Narrow.
(B) Ovoid.
(C) Square

104. Preserving
the arch
form also
affects
stability of
the
treatment
results.
Selecting the archwire on the
pretreatment model by adapting the
archwire on the incisal edges and cusp
tips of the teeth

105. There is ample
evidence in the
literature that
expansion in the
lower arch,
particularly in the
canine region is
unstable, and
little or no
evidence to the
contrary.
Pretreatment
Posttreatment
after 10-year retention.

106. When the lower
arch is rolled in
lingually, as occurs
in most palatal
expansion cases
and many deep
bite cases, then
buccal uprighting
in the lower arch
is indicated for
stability

107. Alignment using larger arch form

108. The intercanine
width of each
patient is
determined by
muscular balance,
and any
1: intermolar width; 2:
intercanine width; 3: molar
depth; 4: canine depth.
unintended
expansion in this
region could
cause instability

109. Orthodontic
archwires play a significant role in expansion of
the
dental arch.

110. The preformed
arch wires are
not
easily
customizable
and may
contribute to
arch form
development
during early
stages of
treatment.

111. Pre-
formed NiTi
archwires are
available in various
shapes
and sizes, and their
average intercanine
width could
exceed the natural
mandibular
intercanine width by
almost 6 mm.

112. Thus, it is
important to
select prefabri-
cated NiTi
archwires that
are similar to
the patient arch
form to
minimize
changes and
reduce possible
relapse.
Template
with
maxillary
and
mandibular
arch forms

113. The
therapeutic
arch form
should be de-
signed by
considering
the original
arch form of
the
patient and
treatment
objectives.
Ricketts pentamorphic arch
form template

114. Most orthodontists
selected archwires
subjectively by
visual assessment of
the adaptation of
the archwires to the
facial axis or facial
surface of the teeth,
incisal edges and
cusp tips, or the
facial portion of the
proximal contacts.
Contoured nickel-
titanium arch
superimposed on
a model.

115. Point 17:
determine whether
the lower arch has a
tapered, square, or
ovoid form .

116. Clear
templates can
be used to
assess the
patient's
lower model
at the start of
treatment.

117. Arch form control early in
treatment
It is recommended that
all round wires be
stocked in ovoid form
only . this helps to limit
inventory. The opening
wires will normally be
.0155 or ,0175
multistrand, .016 HANT,
or sometimes .014 steel.
These may all be used in
ovoid form, with no
customizing.

118. Arch form control early
in treatment
The manufatcured shape
of rectangular HANT wires
cannot be customized. It
is therefore necessary to
stock them in tapered,
square, and ovoid form,
because (like the heavier
round wires) they should
be used in the
approximate form for the
patient, as determined
using the clear templates.

119. Arch form control early
in treatment
Rectangular HANT
wires may be in place
for several months, and
they do influence the
patient's arch form,
especially in the
important canine
region. If not used in
the appropriate
tapered, square, or
ovoid shape, they can
cause undesirable
changes in the patient's
starting arch form