Utility Arch

UTILITY ARCH

Every major approach to orthodontics has had one characteristic

which stands out in the minds of orthodontic clinicians universally as a
medium for describing that particular approach or technique. Probably the
most recognizable single entity in the bioprogressive therapy would be that
of the UTILITY ARCH. It forms the base unit around which the mechanics
in all types of cases can be employed. It is the catalyst which ties together all
the different types of mechanotherapy.

The utility arch was born following the observation of depressed

lower, second bicuspids in extraction cases. Following the move to lighter
forces into the range Storey’s recommendations from a studies in 1952, it
was not until about 1958 that oblique x ray studies showed, with sectional
retraction, the lower second bicuspid could not withstand the tipping force
against the first molar during unusual space closure.

It has been assumed, based on previous histological work and the

ascertains of biologists and histologists in the field, that intrusion of teeth
was impossibility. During space closure with loops, however, the canines
often tipped backward excessively, particularly with rapid closure. In
addition, the molar and bicuspid as a unit both tipped together. Actually, this
action intruded the bicuspid.

In seeking a method to maintain an upright position on the lower

molar and to thereby prevent bicuspid intrusion and the further collapse of
the bite as many had previously witnessed in extraction cases. Ricketts made
an attempt to employ the four lower incisors as anchorage in some manner.
Single tubes were still in use on the lower molars. So, a simple .016 round

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wire was formed as a continuous arch, placed under the second bicuspid
brackets and loped over the molar tubes at the end, to be locked down
behind the extension of the section retractor. This move before activation put
the forward part of the arch downward toward the sulcus and, as it was
raised and engaged in the lower incisors, it exerted an elongating affect on
the bicuspid as a lever against the molars.

Fig. 1
Fig 1 When the lower utility arch is engaged In the lower Incisors, approximately
50 to 75 grams (A) of Intrusive force should be applied. Slight labial root torque
(5° to 10°) allows the lower Incisor to avoid cortical bone in its intrusive
movement (B).

This set up served to keep the anchor unit upright In observing the
behaviour of this mechanical arrangement it was soon discovered that the
lower incisors tended to tilt forward, but also they were seen-to depress.
Careful examination of intraoral x-rays and cephalometric tracings
confirmed that the incisors had intruded. This rapid movement tended also to
extrude the canine and tip it distally as the sectional was employed at that
time.

Simultaneous with that development Ricketts attempted to reduce the

wire size and character together with loop designs to keep the force within
the 150 gins limit hypothesized then for cuspid retraction. The need for

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lighter wires with milder forces had suggested the need for narrower bracket
slots. A move down to the .018 bracket was made after certain experiments,
and because of the discovered need for a second wire or section to operate in
a different plane of space, the dual or double tube was initiated. Also in
order to control the flaring of the lower incisors, the force was further
reduced and a .016 x .016 blue Eligilogy was designed. Because of the span
in the arch designed. Because of the need for a longer level with lighter
force, it took the present form of the U arch. A step mesial to the molar was
made as a buccal bridge section was formed together with an anterior step to
reach up to engage incisors. In the beginning, it was only to be used together
with retraction sections in extraction cases.

However after having made the observation of intrusion of the lower

teeth, further applications of this design were made. Tipbacks against the
molars with light wires began to show also an intrusion of the lower canines.
The incisors remained in deep bite as it then became a greater problem to
intrude the lower incisors through the depressed canines without again
extruding them and tipping them distally. Obviously it was almost an
impossibility to work these teeth simultaneously in the most desired
positions in both planes of space. The utility arch then became the method of
choice as a starting appliance in deep bites or with crowded lower anterior
conditions.

Multiple loops were designed to engage the anterior teeth in crowded

cases and subsequently it was seen that a wide variety of conditions could be
handled. It could be used to gain arch length it could be used to close arch
length. The loops could be incorporated at the location of any of the bends
because the form of the arch itself constituted long vertical loops on either

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side.

Fig. 2
Fig. 2 Mandibular utility arch

It was particularly amenable to intraoral adjustments. For this reason,

it was given the name utility arch, simply because of its utility. It therefore
became the starting appliance for class II division 1 and class II division

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Fig 3 Intraoral adjustments

It becomes the appliance in the mixed dentition case in order to avoid

most of the need for banding of the primary teeth.

Many clinicians tried to abuse the use of the utility as did Ricketts in
the beginning. It is hard to realize that a .016x.016 blue Elgiloy wire will
offer sufficient strength and stability to do the job for which it is proposed.
Just because the utility arch is a starting appliance, it should be understood
that it can be employed again any time during the course of treatment to
regain lest overbite due to retraction of anteriors. A wide Varity of stock
utility arches are available and can be adapted into routine daily practice.

Fig 4 Utility Arch

TYPES OF UTILITY ARCHES: -

Although many configurations for utility arches have been described
four types of arches can be defined, based on their use.
Passive Utility Arch

The Passive Utility Arch (Fig. 5) is used for stabilization or space

maintenance in either the mixed or permanent dentition. A passive utility

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arch can be used in the mixed dentition to maintain arch length during the
transition of the dentition. In many respects, the utility arch acts in the same
manner as a lingual arch because the passive utility arch prevents the mesial
migration of the molars, particularly in the lower arch. The utility arch also
may influence the eruption of the posterior teeth by holding the cheek
musculature away from erupting teeth, allowing for spontaneous arch
widening.

Fig. 5. Passive utility arch. Note that the posterior vertical segment fits snugly
against the auxiliary tube of the lower molar band.

The passive utility arch also is used in the permanent dentition,

primarily for the maintenance of anchorage. In non-extraction patients, the
passive utility arch is particularly useful after molar distalization has been
completed

In many techniques (e.g., Wilson distalizing arch, NITI coils,

distalizing magnets), a large space is opened posterior to the upper second
premolars as the first permanent molar is distalized . One of the challenges
to the clinician is to maintain molar anchorage while the upper premolars are
retracted. In combination with a transpalatal arch, extraoral traction, or a
Nance holding arch, a passive utility arch can be used to incorporate the

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anterior teeth as anchor units . “Driftodontics” (i.e., tooth movement

produced without active orthodontic forces being applied) then are used to
allow the premolars to migrate posteriorly without active orthodontic
treatment.
Passive utility arches also are used as anchorage appliances in
extraction cases . Prior to canine retraction, a passive utility arch that
extends from the first molars to the incisors is placed. Canine retraction then
is initiated, using the incisors as additional anchor units.)
Activation. No activation of the passive utility arch is required.
Intrusion Utility Arch: -
The intrusion utility arch (Fig. 6) is similar in design to the passive
utility arch, but this arch is activated to intrude the anterior teeth (Otto et al.,
1980).

Fig. 6. Intrusion utility arch. A) The intrusion utility arch first is bent passively to
the existing occlusion. Note that the posterior vertical segment lies at least 5 mm
ahead of the auxiliary tube on the lower first molar. B) Retraction of lower
incisors can be produced by grasping the distal end of the molar segment with a
pair of Weingart pliers, pulling the segment posteriorly, and then turning the
segment gingivally. C) Intrusive forces can be produced by using a loop-forming

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plier to place an occlusally-directed gable bend in the posterior aspect of the

vestibular segment.
After activation, a light continuous force is delivered by the long lever
arm from the molars to the incisors. The utility arch should produce 60-100
gms of force on the lower incisors, a force level considered ideal for lower
incisor intrusion (Bench et al., 1978). The overall effect is intrusion and
possible torquing of the lower incisors as well as a tipping back of the lower
molars . Expansion or contraction of intermolar width can be achieved by
widening or narrowing the archwire. Molar rotation is produced by
appropriately activating the molar segments of the arch.

Activation. Two types of forces can be produced using this design:

retraction and intrusion. With a simple utility arch, a modest amount of
incisor retraction can be achieved by grasping the end of the molar segment
with a Weingart plier distal to the molar tube and then turning this segment
gingivally after pulling the wire posteriorly through the tube (Fig. 6B). Care
must be taken that the protruding end of the wire does not encroach on the
soft tissue of both the cheek and gingiva. This type of activation prevents
proclination of the lower incisors during intrusion.

Intrusion of the anterior teeth can be produced in one of two ways.

First, the utility arch can be bent passively to fit the existing occlusion, as
has been described previously. After ligating the utility arch into the anterior
brackets, an intrusive force can be produced by placing an occlusally-
directed gable bend in the posterior portion of the vestibular segment of the
archwire (Fig. 6C). A loop-forming plier, such as the 881 loop-forming plier
(Masel Orthodontics, Bristol, PA), can be used for this type of intraoral
activation. These loop-bending pliers must have a concave surface next to

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the loop-forming portion of the plier; therefore, not all loop-bending pliers,
such as omega loop-forming pliers, can be used for intraoral activation of the
utility arch.

Bench (1988) has advocated an alternative method of activation of the

utility arch to produce intrusion. This type of activation involves placing a
tip-back bend in the molar segment. The tip-back bend causes the incisal
segment of the archwire to lie in the vestibular sulcus. The intrusion force is
created by placing the incisal segment of the utility arch into the brackets of
the incisors. This activation creates a moment that allows for the long action
of the lever arm of the utility arch to intrude lower incisors. It has been our
experience that placing distal crown torque in the molar segment sometimes
leads to a posterior tipping of the first molars. Thus, activating the utility
arch by placing a gable bend in the posterior aspect of the vestibular segment
(Fig. 6C) seems to avoid unwanted molar tipping. In the case of a maxillary
utility arch, tipping of the molars also is reduced through the concurrent use
of a transpalatal arch.

Bench (Bench et al., 1978; Bench, 1988) also recommends the

placement of buccal root torque in the lower molar region to anchor the roots
of the molars in cortical bone. This type of force also produces lingual
crown torque that is counterbalanced by placing 10 mm of expansion in the
utility arch in the molar region during appliance fabrication.

Retraction Utility Arch: -

The most common type of utility arch used by the senior author is the
retraction utility arch (Fig. 7A). This type of utility arch can be used in either
the mixed or permanent dentition to achieve retraction and intrusion of the

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incisors by incorporating loops in the archwire anterior to the anterior

vestibular segment.
Retraction (Fig. 7B) and intrusion (Fig. 7C) can be produced by
activating the retraction arch in a similar fashion previously described for the
intrusion utility arch. The incorporation of the loop into the design allows for
a longer range of activation. Perhaps the most common use of the retraction
utility arch is during the final stages of comprehensive edgewise treatment.
In an extraction case in which the canines have been retracted, space opens
distal to the upper lateral incisors. In non-extraction cases, a similar but
smaller space is often open distal to the lateral incisors due to molar and
premolar rotation as well as due to Class II mechanics.

Fig. 7
Fig. 7. Sagittal view of maxillary re' action utility arch. A) Before activation. B)
Retraction of the molar segment of the archwire. C) An occlusally-directed gable
bend has been placed in the vestibular segment of the archwire to produce incisor
intrusion.

A retrusion utility arch can be used to close this space by retracting

the upper incisors. This arch also provides the necessary intrusion that often

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must precede the retraction of anterior teeth.

The retraction utility arch is used less commonly in the mandible.

However, it may be used in cases of dentoalveolar anterior crossbite in
which there is some proclination and spacing of the lower incisors. In these
types of cases, the anterior crossbite can be corrected using a retrusion utility
arch, while the spacing between the incisors is eliminated through the use of
elastomeric chain.

Utility arches also can be combined with bonded orthopedic

appliances. For example, buccal tubes can be incorporated into a variety of
acrylic splint appliances (e.g., bonded RME, Herbst). A utility arch can be
fabricated so that it is anchored posteriorly in the buccal tubes of the bonded
appliance and then can be used to move the anterior teeth in all three planes
of space.

At this point, a 900 bend is placed with a 142 arch-bending plier. A

loop-bending plier is used to place a loop in which the end of the anterior leg
crosses behind the posterior leg. After a 5-8 mm vertical segment is formed,
another right angle bend then carries the wire across the anterior teeth. A
gentle anterior contour is placed in the wire to simulate arch form, and an
offset also is placed in the canine region.

On the other side of the arch, the anterior vertical step is created in the
interproximal area between the lateral incisor and canine. The retraction loop
is formed with the loop-bending plier and then the loop-bending plier (rather
than the arch-forming plier) is used to create the 90° bend in the horizontal
vestibular segment .The wire then extends to the posterior vertical segment
at the middle of the second premolar. In most instances, the length of the

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horizontal vestibular segment can be estimated, based on the length of the

horizontal segment on the opposite side. Care must be taken to make sure
that the utility arch does not encroach upon any fixed appliances present,
including ball hooks or Kobayashi hooks.

Activation. As with the intrusion utility arch, there are two possible
types of activation. First, a Weingart plier can be used to grasp the extension
of the utility arch posterior to the auxiliary tube. The wire is pulled 3-5 mm
posteriorly and then bent upward at an angle. Care must be taken that this
protruding end of the utility arch does not impinge on the cheek or gingiva.
Second, an occlusally-directed gable bend in the vestibular segment can be
used to produce intrusion, as has been shown previously in Fig. 7C.

Protraction Utility Arch: -

The protraction utility arch (Fig. 8) is useful for proclining and
intruding upper and lower incisors.

Fig. 8
Fig. 8. Protraction utility arch. Note that the posterior vertical segment is flush
against the auxiliary molar tube. When passive, the anterior portion of the utility
arch should lie approximately 2-3 mm ahead of the incisor brackets.

In the permanent dentition, it is used commonly for proclining and

intruding maxillary incisors in Class II, division 2 cases, especially in

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patients with an impinging overbite (Fig. 9).

Fig. 9.
Fig. 9. Movement of upper incisors using a protraction utility arch. A) Simple
flaring. B) Protrusion and intrusion.

This archwire is used to provide clearance between the upper and

lower incisors to allow for placement of brackets on the lower dental arch.
The protraction utility arch also is used during the presurgical orthodontic
phase of treatment in patients undergoing a mandibular advancement to
decompensate the position of the upper incisors.

This type of utility arch also is used during the mixed-dentition period
prior to functional jaw orthopedic appliance therapy. In the case of Class II
patients who have retruded upper incisors, brackets can be placed on the
upper anterior teeth, and bands can be placed on the upper first molars
(perhaps supported by a transpalatal arch). A utility arch can be used to
procline and intrude the incisors as necessary. Often a simple intrusion arch
without loops is needed in the lower arch.

The anterior vertical step is usually 5-8 mm in length, depending on

patient tolerance. The incisal segment courses through the incisor brackets,
and the utility arch is completed in a similar fashion on the other side.

Activation. When the protrusive utility arch is passive, the anterior

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segment lies about 2-3 mm anterior to its ultimate position in the incisor
brackets. The protrusive force is produced by tying the anterior segment of
the utility arch into the anterior brackets. An occlusally-directed gable bend
in the posterior aspect of the vestibular segment is used to produce intrusion.

The protrusion arch is reactivated by removing the anterior segment

from the brackets, bending the posterior vertical step forward from 90° to
45° and replacing the arch wire in the brackets. Other adjustments can be
made in both the anterior and posterior vertical steps to produce further
activation.

CLINICAL PROBLEMS
By far, the major complications associated with the use of utility arch
involve the soft tissue. One of the major difficulties in fabricating the utility
arch, whether it is for the maxilla or the mandible, is in placing the
horizontal vestibular segment between the gingival and buccal tissues. If the
posterior step is made too long, or if the horizontal segment encroaches on
the gingival tissue, the wire can become embedded easily. If the horizontal
vestibular segment is placed too far laterally, tissue irritation and the buildup
of fibrous tissue along the inside of the cheek can occur; In instances in
which tissue irritation occurs in the areas adjacent to the vestibular portion
of the utility arch, clear or grey sleeving (“bumper sleeve”) may be used to
shield the tissue from the edges of the wire.

Another major area of concern is the formation of the loops of the

retraction utility arch. If these loops extend too far into the vestibular area or
protrude anteriorly, severe irritation can result and patient discomfort can
occur. The patient should be given wax at the delivery appointment to aid in

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the break-in period after the utility arch has been inserted.

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