Mixed dentition orthodontic treatment /certified fixed orthodontic courses by Indian dental academy

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INDIAN DENTAL ACADEMY
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Mixed Dentition Orthodontic Treatment
•Introduction
•Rationale for Early Treatment
•Benefits of Early Treatment
•Difficulties of Early Treatment
•Treatment Planning in Mixed Dentition
•Treatment Modalities

Mixed Dentition
“The developmental period after permanent
first molars and incisors have erupted and before
remaining deciduous teeth are lost”
AAO recommends visit to an orthodontist
by Age of 7

Favourably developing occlusion at this stage
has 3 characteristics:
• Molar relationship is usually endon and typically
transforms into a class I during the transition from a
mixed dentition to permanent dentition
• Nicely aligned permanent incisors often sporting
their mamelons with short clinical crown and a 1-3
mm of overbite and overjet
• A small space either mesially or distally to a
permanent canine

Rationale for Early Treatment
•Some malocclusion can be prevented or
intercepted
•Diphasic treatment is considered more logic
and sensible
•During phase I, craniofacial skeletal growth is
controlled and morphology improved so that
later tooth positioning is easier

Rationale for Early Treatment
•One may be able to remove etiological factors,
enlist natural growth forces, and provide
differential crown response and obtain a balanced
profile prior to eruption of most permanent teeth
•Clinician can utilise growth better in the young
and there is more growth available

Benefits of Early Treatment
•Possibility of achieving better results
•Early treatment of serious, deleterious habits is
easier than treatment after years of ingrained
habit reinforcement
•Psychological advantage to early treatment in
some children
•Younger patients are often more cooperative and
attentive

Difficulties of Early Treatment
• Diphasic treatment may lengthen
chronologic treatment time
• Early diagnosis and treatment planning are
more tentative and the periodic cephalometric
reassessment is a necessity
• Increased cost factor

Treatment Planning
in
Mixed Dentition…..

Conditions that SHOULD BE treated……
•Loss of primary teeth endangering the available
space in the arch (space maintainer)
• Space closure that had occurred due to
premature loss of primary teeth ( Space
Regaining)
• Supernumerary teeth that may cause
malocclusion

•Crossbites
•Malocclusion due to habits
•Neutroocclusion with extreme labioversion
of the maxillary anterior teeth

• Class II (distoocclusion) cases of functional
type
• Class II (distoocclusion) cases of dental type
• Class II (distoocclusion) cases of Skeletal
type

• Localised spacing between the maxillary
central incisors for which orthodontic therapy
is indicated
• Malposition of a teeth that interfere with
normal development of occlusal function

Conditions that MAY BE treated……
•Class II malocclusion of a skeletal type
particularly if diphasic treatment is indicated
•Class III malocclusion where early treatment
is feasible
•Gross disharmonies of apical bases
•All malocclusions accompanied by extremely
large teeth

Treatment Modalities
I. Treatment of Non Skeletal Problems
II. Treatment of Class II malocclusion
III. Treatment of Class III malocclusion

Treatment of Non Skeletal
problems…

Intraarch Problems
Space Problems
Eruption Problems
Occlusal relationship Problems
Crossbites
Vertical Problems

Space Problems…

Transitional Appliances
In the mixed dentition 2.5 mm per side can be
gained in the mandibular arch and about 2 mm
per side can be gained in the maxillary arch
( Moyers et al 1976)
This space has to be maintained and
2 appliances that are used as holding
appliances:
1. Transpalatal arch
2. Lingual arch

Transpalatal Arch
•Extends from one maxillary
first molar along the contour
of the palate to the molar on
the opposite side.
•Major function in the mixed
dentition is to prevent the
mesial migration of the upper
I molars during the transition
from the deciduous molars to
the second premolars.www.indiandentalacademy.com

•Also capable of producing molar
rotations and changes in root torque by
sequential unilateral activation of the
appliance.
•Also used for molar stabilization and
anchorage.

Lingual Arch
•Usually used in the
mandible as part of the
early treatment protocol.
Has a function similar to
TPA.
•It extends along the
lingual contour of the
mandibular dentition from
the I molar of one side to
the other.

•Optional adjustment loops can be placed in the
region of II deciduous molars.
•In contrast to TPA the lingual arch is usually
removed after the eruption of II premolars is
completed.

Space Problems
(Moderate severity)
Missing primary teeth with adequate
Space – Space Maintenance

Space Maintenance
Early loss of primary teeth presents a
potential alignment problem because drift
of permanent or other primary teeth is a
likely sequela. Hence space must be
maintained.
Many treatment are successfully used for
specific situations …..

Band and loop space maintainer
• unilateral fixed
appliance
• indicated in posterior
segments
• mostly used to
maintain space of
primary first molar
before eruption of
permanent first molar

• Also used to maintain the space of either
a primary first or second molar after perm
first molar has erupted

Distal shoe space maintainer
• Appliance of choice
when a primary
second molar is lost
before eruption of
permanent I molar

• Consists of a metal or a plastic guideplane
along which the permanent molar erupts.The
guideplane must extend into the alveolar
process so that it contacts the permanent first
molar approximately 1 mm below the mesial
marginal ridge before it emerges from the
bone.

Lingual Arch Space maintainer
• Attached to bands on
the primary II or
permanent I molars and
contacting the cingula
of the maxillary or
mandibular incisors,
prevents the anterior
movement of the
posterior teeth ad
posterior movement of
the anterior teeth

•Indicated when multiple primary posterior
teeth are missing and permanent incisors
have erupted

Partial Denture space maintainer
• Most useful in bilateral
space maintenance
when more than 1 tooth
has been lost per
segment
• Also indicated in
posterior space
maintenance in
conjunction with
anterior teeth for
esthetics

Localized Space loss (3 mm or less) –
Space Regaining
Space Problems
(Moderate severity)

Maxillary Space Regaining
• Permanent maxillary I molars can be tipped
distally to regain space with either a fixed or
removable appliance but bodily movement
requires a fixed appliance.
• A removable appliance is one with Adam`s
clasp and helical finger spring adjacent to the
tooth to be moved
• Tooth can be moved upto 3 mm during 3-4
months of full time wear
• The spring is activated approximately 2 mm to
distalize 1 mm movement per month

• When bilateral maxillary space regaining is
needed either by tipping both molars or by
bodily movement, an extra oral force via a face
bow to the molars is effective
• The force is directed specifically to the teeth to
be moved
• Approximately 100 g of force per side is
appropriate
• 14 – 16 hrs of wear per day is minimal

Mandibular Space Regaining
• The mandibular appliances are not satisfactory as
it is prone to breakage and may be difficult to
retain
• If space has been lost on 1 side of the arch, the
appliance of choice is a removable lingual arch
incorporating a loop that can be opened to
provide the distal force
• An alternative fixed appliance is the lip bumper,
which is a labial appliance fixed to tubes on the
molar teeth. The appliance presses against the lip
which creates the distal force to tip the molars
posteriorly www.indiandentalacademy.com

Maxillary Midline Diastema
• Esthetic compliant
• Position of central incisors that inhibit
eruption of lateral incisor or canine
• Diastema of more than 2mm
A small diastema present in
children is not necessarily an indication for
orthodontic treatment
Major indications for diastema closure :

• A small but unesthetic diastema (2 mm or
less) can be closed by tipping the central
incisors together
• A maxillary removable appliance with
clasps, finger springs and possibly an
anterior bow is a successful appliance
• More large unesthetic diastemas will
require bodily repositioning of the incisors
where teeth can be moved along a
segmental arch wire that is placed in
bonded brackets on the incisors and the
force is provided by an elastomeric chain

Midline Discrepancy from intra arch asymmetry
• This is a potential problem which is usually
exhibited as a shift of the dental midline to one side
because of premature loss of 1 primary canine
• If archlength is adequate the incisors can be aligned
to their optimal location using removable appliance
and finger spring
• If a bodily drift has accompanied the midline
change then the anteriors must be bonded and
aligned with an arch wire.The force is generated by
a coil spring
• Retention will be needed till permanent teeth eruptwww.indiandentalacademy.com

Space Problems
(Greater severity)
Severe Crowding of more than 4 mm

Crowding
Most common type of malocclusion in
mixed dentition is crowding.They usually present
with class I molar relationship or a tendency
towards either Class II or class III malocclusion.
“A disparity in the relationship between the
tooth size and jaw size, which results in
imbrication and rotation of tooth”
(AJO 1983 May, McNamara)

1. Hereditary Crowding
2. Environmental Crowding
3. Late lower arch Crowding
Types of Crowding:

Serial Extraction
“The sequential removal of deciduous teeth to facilitate
the unimpeded eruption of permanent teeth.”
Procedure began in Europe
Advocated by No. of individuals.
•Hotz (1948,1974)
•Kjellgran(1948)
•Terwilliger (1950)
•Lloyd (1953)
•Palson(1956)
•Dewell(1954,1959,1967)
•Ringenberg (1964)

*May be indicated when it is determined with a fair degree of
certainty and there will not be enough space in the jaws to
accommodate all the permanent teeth in their proper alignment.
*Another indication is the early loss of one or both mandibular
canines and the resultant midline discrepancy.
*The chances of success with this treatment are relatively good with
class I malocclusion and if they are undertaken in Class II or Class III
malocclusion, great caution must be taken not only in solving the
emerging intraarch problem but also the existing interarch relationship.
*Usually are not indicated in situations of extreme skeletal imbalance
Serial Extraction…
Graber(1966)

Ringenberg(1964)
cites a discrepancy of 7 mm or greater for Serial Extraction.
Profit(1986)
Is indicated with a space discrepancy of 10 mm or greater.
Vanarsdall(1992)
May be combined with RME in certain patients
with significant arch size discrepancy who also have narrow
tapered maxilla and negative space present in the corner of
mouth during smiling.
Serial Extraction…

Methods of Serial Extraction
1. Dewell`s method
CD4
2. Tweed`s method
D4C
3. Nance`s method
D4C

EXTRACTION OF PRIMARY CANINES:
To relieve incisal crowding
Radiographic Examination
A Crescent pattern of resorption on the
mesial of the primary canine roots.
Signifies that premolars are emerging
favourably ahead of permanent canines.
None of the unerupted permanent teeth
have reached ½ root length.
Step 1

EXTRACTION OF PRIMARY I MOLARS:
Incisal crowding has improved, overbite has
increased and extraction site is reduced in size.
Radiographic Examination:
Reveal that first bicuspids have reached ½
root length, and is favourable for extraction of Ds to
speed up the eruption of 4s.
Step 2

EXTRACTION OF FIRST BICUSPID:
When permanent canines have developed
beyond ½ root length, to accelerate their eruption
the first bicuspids are extracted.
Step 3

As a result of Serial Extraction there is an
increased deep overbite with distoaxial inclination of
canines, mesioinclination of second bicuspids, Clas I
molar relationship, improved alignment of the
incisors and residual spaces at extraction sites.
After mechanotherapy is completed, there
will be an ideal occlusion with normal overbite,
overjet, parallel canine & bicuspid roots.

Eruption Problems
• Ankylosed primary teeth
• Supernumerary teeth
• Ectopic eruption

Ankylosed primary teeth
• They constitute a potential alignment problem
for the permanent teeth
• Although usually are resorbed in normal
manner, occasionally are not exfoliated on
schedule and are retained between the tooth and
the hard tissue in the cervical region
• Management consists of maintaining it until an
interference with eruption or drift of other teeth
begins to occur, then extracting it and placing a
space maintainer if needed

Supernumerary teeth
• Can distrupt both the normal eruption of the
other teeth and their alignment if eruption
does occur
• Most common location is the anterior maxilla
• Treatment is aimed at extraction of the
supernumeraries before the problems arise or
minimizing the effect if teeth have already
been displaced

Ectopic eruption
• Eruption is ectopic when a permanent tooth
causes either resorption of a primary tooth
other than the one it is supposed to replace
or resorption of an adjacent permanent
tooth
• Alignment problem results if the primary
tooth is lost prematurely or if the underlying
permanent tooth is blocked from erupting
• After a period of watchful waiting, and if
the blockage persists for 6 months the basic
approach is to move the ectopically
erupting tooth away from the tooth it iswww.indiandentalacademy.com

• The most common ectopically erupting
permanent tooth other than the I molar is a
permanent maxillary canine with the
resorption of permanent lateral incisor roots
• Radiographically, when mesial inclination
of the erupting permanent canine is detected
and no incisor root resorption is noted, the
treatment of choice is to extract the
overlying primary canine

Occlusal relationship problems
Dental cross bites caused by displacement of
teeth result from bilateral constriction of
maxillary arch and shift of the mandible to one
side
Three basic approaches to treatment of
posterior cross bite are:
1.Equilibration to eliminate mandibular shift
2.Expansion
3.Repositioning of individual teeth

•Treatment is with a split-plate type of removable
appliances:
1. A banded or bonded jack-screw
appliance is commonly used
2. W arch or quad helix are reliable and
easy to use

Expansion should continue at the rate of 2mm
per month until cross bite is over corrected
It requires 2-3 months of active treatment and
3 months of retention
Quad helix is indicated in a combination of
cross bite and finger sucking habit

Vertical problems
Habits and open bites

• Most Children engage in some form of non
nutritive sucking
• Intervention is usually not indicated until 5
years of age
• As long as sucking stops before the eruption
of permanent incisors, most of the dental
changes resolves spontaneously
• At the time of eruption of permanent incisors,
Counseling can be given
Habits and open bites

If counseling does not work, the patient can
be fitted with a cemented reminder appliance
that consists of maxillary lingual arch and a
crib constructed of soldered wire so that it is
difficult to insert the thumb into the mouth

The open bites associated with sucking often
resolves after sucking stops and the remaining
permanent teeth erupt
Open bites that persists almost have a
significant skeletal component

Deep bite
The problem may result from :
1. Reduced lower facial height and lack of
eruption of posterior teeth
2. Or over eruption of anterior teeth

Treatment
•Removable bite plate appliances to reduce the overbite.
Can be used for patients who have less than normal
eruption of posterior teeth.
•An anterior bite plate is incorporated into a removable
appliance so that mandibular incisors occlude with the
plastic plane lingual to maxillary incisors.
• This prevents the posterior teeth from occluding and
encourages their eruption.Full time wear appliance.
•Bite plate must continue to be worn after proper
vertical dimension is established

Anterior Bracket Placement
•Since only permanent incisors are erupted,
placement of brackets only in these teeth are
indicated.
•The alignment can be achieved through a
relatively simple sequence of arch wires.
•The utility arch involves the placement of bands
on the first molars, a transpalatal arch can be
used to anchor the utility arch posteriorly.

Anterior Bracket Placement
Utility arch :
•In significant no. of
patients with tooth size
arch size discrepancy
patients irregularities
exists in alignment of
anterior teeth.
•This also occurs as a
consequence of RME in
mixed dentition.

Types of Utility Arch
Based on their use ( McNamara 1986)
1.Passive Utility Arch
2.Intrusion Utility Arch
3. Retraction Utility Arch
4. Protraction Utility Arch

Early treatment
of
Class II Malocclusion

Mixed treatment goals often focuses on
skeletal rather than dental correction.To
design a treatment plan the clinician must
understand the growth and development
pattern and know the effects of chosen
treatment modality.
Growth affects orthodontic treatment
usually favourable but sometimes
unfavourable. When and how much growth
will occur is completely unpredictable.

Some useful factsabout jaw growth in Mixed Dentition…*
Between ages of 5-10 years, the intercanine dimension may
increase by 3 mm.After the age of 10, there are no changes in
the width
The space in the maxillary arch from molar to molar
increases by 2 mm.In the mandible, there is a decrease of 2 mm
to an increase of 4 mm.
The palatal midline suture closes at about the age of 13 in
girls and 16 in boys. The frontopalatal suture closes at around
age 2.
Growth rates peak for girls at age 13 and for boys at age 15.
*Dr.Gerald Nelson, Orthodontic dialogue 1997 issue Vol 9

Many treatment approaches are currently available
to the orthodontist for altering the occlusal relationships
typically found in class II malocclusions.Each treatment
approach however differs in its effect on the skeletal
structure, sometimes accelerating or limiting the growth
of various structures involved
Treatments:
•Extraoral Traction Appliances
•Functional Jaw Orthopaedics
•Extraction Procedures
•Arch Expansion Appliances

Components of skeletal Class II malocclusion
•Prognathic maxilla with orthognathic
mandible
•Retrognathic mandible with
orthognathic maxilla
•Combination of both
•Vertical problems – increased
maxillary excess

Maxillary skeletal problems
Maxillary skeletal protrusion:
Most common treatment is extra-oral traction.
These appliances are divided into 2 types: i) Facebows
ii) Head gears
Facebows:
Facebows attached to tubes on the upper first molar bands
Head gears attached directly to the arch wire or to the
auxiliaries connected to the arch wire ( Berger 1992).

Cervical facebow also called low pull facebow. Mostly
used in patients with decreased vertical dimension.
Innerbow attached to buccal tube of the I molar
Outerbow connected to strap that extends to cervical region
and anchored against dorsal aspect of neck. Outerbow Lies
above the plane of occlusion to direct the force through the
center of resistance and prevent distal tipping of the
molars.Cervical traction increases the vertical dimension by
extrusion of molars.

A high pull facebow is used in individuals in whom increases
in vertical dimension are to be avoided.The facebow is
anchored to occipital anchoring unit to produce a more
vertically directed force.It allows automation of the mandible
and maximizes the horizontal expression of mandibular
growth (Tweed1966).
A straight pull face bow is a combination of cervical
and head cap

Maxillary skeletal Retrusion
• It is extremely difficult to treat directly, except through
orthognathic surgery, and usually
• No attempt is made to correct maxillary skeletal retrusion
in mixed dentition
• Occasionally retrusion is treated indirectly by using
appliances such as posterior bite block or a vertical pull
chin cap that produce a slight upward and forward
movement of the maxilla and a counter clockwise rotation
of mandible(Dellinger1973,Pearson1978)

Maxillary deficiency
Transverse Maxillary Constriction
• Skeletal Maxillary constriction is
distinguished by a narrow palatal vault.
• Can be corrected by opening the midpalatal
suture, which widens the roof of mouth and
floor of nose
• Growth in this suture is an important
mechanism for normal widening of arch

Orthopaedic Expansion
•The corner stone of early expansion treatment in patients with
arch length discrepancy problems is RME.
•RME is most essential component of mixed dentition treatment
protocol.
•Of all the areas of craniofacial complex, the most readily
adaptable is the transverse dimension of maxilla. expansion is
produced by applying a lateral force against the posterior
maxillary dentition producing a separation of mid-palatal suture.

•According to Nelson (1972,1982), RME is easily achieved in a
growing individual. The acrylic has an additional advantage of acting
as a posterior bite block that covers the occlusal surface of posterior
dentition and prevents the extrusion of posterior teeth.It is used in
patients with steep mandibular angles.
•A transpalatal width of 33 – 35 mm is considered ideal for a patient
during mixed dentition period (Spillane & McNamara 1989)
•Rapid palatal expansion produces an increase in the maxillary arch
perimeter at the rate of 0.7 times the change in I premolar width. In
treatment planning, it would be helpful to predict the gain in arch
perimeter for a given amount of transverse expansion ( Nanda ,
Adkiins AJO – 1990 March).
Orthopaedic Expansion…

•Although the use of RPE procedures in the primary and mixed
dentition has been reported in the literature, and the clinical
indications have been proposed (Bell, 1982; Bishara et al.,1987;
Nicholson et al., 1989; Halazonetis et al., 1994), relatively little has
been published concerning the specific cephalometric alterations
induced by this appliance.
•Haas (1970) stated that once the mid-palatal suture opens, the
maxilla always moves forward and downward, and this causes a
downward and backwardrotation of the mandible, which decreases
the effective length of the mandible and increases the vertical
dimension of the lower face.

•Wertz (1970) suggested from his analysis of lateral cephalograms
that the maxilla drops down consistently, but rarely moves forward
significantly. However, he had no control group against which to
assess the vertical changes.
•This was later confirmed by da Silva et al. (1991), who foundthat the
maxilla did not show any statistically significant alterations in the
anteroposterior position over the 14–16 days of appliance activator. The
maxilla displayed a tendency to rotate downward and backward . The
mandible rotated down and posteriorly.

•McNamara (1993) in a study of the effects induced by a RPE appliance
observed that widening the maxilla lead to a spontaneous forward
posturing of the mandible during the retention period and that a
spontaneous correction of Class II relationship can be found after 6–12
months.
• Velàzquez et al. (1996) in a long-term study regarding the effects of RPE
reported that the modest, but potentially unfavourable changes induced by
the RPE device, such as an open bite or mandibular posterorotation, are
reversible. They found that, following termination of orthodontic
treatment, these undesirable effects were almost completely resolved.

•The appliance of choice is a bonded RME appliance. It
incorporates a hyrax type screw into a framework made of wire
and acrylic, is used to separate the halves of maxilla.

The screw is activated ¼ turn (90°) per day (0.22 mm) until the
lingual cusps of upper posterior teeth approximate the buccal cusp of
lower posterior teeth.
After the active phase of expansion is completed, the appliance
is left passively for 4-5 months to allow for a reorganization of the
midpalatal suture.at the end of treatment time appliance is removed
and patient is given a removable palatal plate .RME affects een the
circumzygomatic and circummaxillary sutural systems (starnbach et al
1966)
Active expansion produces mid line diastema between two
central incisors .a mesial tipping of maxillary central and lateral
incisors occurs .
ACTIVATION

Mandibular Expansion Appliances
The Schwarz appliance :
Indicated in patients with mild to moderate crowding in lower
anteriors.

• It is activated once per week ,producing 0.25mm of expansion.
• Treatment is done for 3 or 4 months ,depending upon incisor
crowding ,producing 3-4 mm of arch length anteriorly.
• After active treatment appliance left passively for 6 months.
ACTIVATION
It is horse shoe shaped appliance that fits along lingual
border of mandibular dentition .a midline expansion screw is
incorporated into the acrylic with ball end clasps in the
interproximal spaces between deciduous and permanent molars

LIP BUMPER
It is useful patients who have very tight or tense buccal and
labial musculature.it lies away from the dentition and shields it
from the forces of adjacent soft tissues
It is an removable appliance that attaches to buccal tubes on
first molar .

It is worn on a full time basis
It not only increases arch length through
passive lateral and anterior expansion
but also serves to upright lower molars
distally adding to arch length increase .

Maxillary dentoalveolar problems
1. simple
2. complex
Divided into two types

Simple problems :
Usually flared or retruded incisors.
Management :
o flared incisors
i. retraction using retraction utility arches
ii. or high pull head gear or straight pull
head gear combined with ‘J’ hooks that are attached to the
arch wires anteriorly or by using a closing arch supported
by headgear (Berger 1992)
o Retruded incisors
protraction utility arches

Complex problems
They involve protrusion of the entire maxillary dental
arch relative to the skeletal portion of the maxilla. The
goal o f treatment is either to retract the upper anterior
teeth following removal of upper 2 premolars or to
move the maxillary dentition en masse in a distal
direction.
This goal is achieved through a no. of treatment options ….

1. Extraoral traction like cervical, straight pull and high pull
face bows as well as high pull, straight pull and low pull head
gear with ‘J’ hooks. Use of interlandi head gear provides an
additional treatment option with variable direction of force. It is
also possible to attach a high pull head gear to the upper arch
and the straight pull head gear to the lower arch simultaneously

2. Distallizing plates (Cetlin’s appliance):
These plates fit against maxillary dentition and produce a
posterior force against the first molars.It’s a Full time appliance
and can be used along with cervical or high pull face bows in
night times.finger springs on the plate tip the crown distally, the
facebow produces distal root torque to maintain an upright
position of molars. They are also useful in regaining space that
was lost due to premature loss of II deciduous molars.

3. Distallizing magnets:
This procedure is used both in late mixed dentition and
permanent dentition. An assembly containing repelling magnets is
placed into the molar tube on the upper I molars and magnets are
placed in repelling position y ligating a sliding yoke to an eyelet on
the premolars. Activation done every done 2-4 weeks produces a
distalizing force which results in posterior movement of the upper
molar. 25% anchor loss is seen (Giannelly 1992)

4. Ni-Ti coils:
They can be incorporated into an appliance system
similar to magnets.they produce a continuous force of 100-
300 g bilaterally.After achieving the molar distallization to a
slightly over-corrected position and they are stabilized with
Nance holding arch or a passive utility arch.The premolars
and the canine are allowed to drift distally due to the pull of
transseptal fibers between adjacent teeth.After 3 or 4 months
e-chain is used to distallize the premolar and canine.A
retraction utility arch or a closing loop arch is then used to
complete anterior space closure.

Mandibular skeletal problems
Mandibular Dentoalveolar Retrusion:
Treated by lip bumper in individual who have very tight
cheek and lip musculature.
Passive utility arch is effective in partially shielding
the eruptive dentition from cheek musculature.

Mandibular Skeletal retrusion
Retrognathic mandible in the growth period is treated by functional
jaw orthopaedic appliances
1. Activator
2. Bionator
3. Frankel II
4. Herbst
5. Twin Block

Activator
According to Anderson &
Haupl, it induces musculoskeletal
adaptation by introducing a new
pattern of mandibular closure.
When the mandible is moved
forward, it results in stretching of
elevator muscles of mastication,
which starts contracting thereby
settingup a myotactic reflex and
causes advancement of mandible.
In the first week, patient is asked
to wear for 2-3 hrs /day in daytime
followed y 3 hours during the day
as well as night time. After 1 week
of usage, trimming plan is
developed.

Bionator
Used in patients with
extremely short lower anterior
facial heights. In these patients
there is no adequate vertical
space for positioning lower
labial pad of Frankel II. It not
only brings the mandible in
forward position but also
increases the vertical dimension
through differential eruption of
posterior teeth.

Herbst Appliance
•Developed by Emil Herbst.
•Uses a telescopic mechanism and
encourages forward repositioning of
the lower jaw as the patient closes into
occlusion.
•Pancherz 1982 & McNamara 1990
have shown that both skeletal and
dental adaptations are produced with
this appliance.
•This was previously used in the
mixed dentition period but now
primarily used as an appliance in
permanent dentition.

Frankel II Applaince
It is a tissue borne appliance, the
base of operation is in the maxillary and
mandibular vestibule and the appliance has
a direct and primary effect on the
neuromuscular system. It is used an
exercise device by retraining or
reprogramming the CNS. It interrupts
normal pattern of muscle activity and
ultimately produces an environment in
which skeletal and dental arch change
occur. It is the appliance of choice in
treatment of patients with severe
neuromuscular imbalance and skeletal
discrepancies. As this is a tissue borne
appliance, maximum skeletal change is
achieved with minimal unwanted tooth
movement. www.indiandentalacademy.com

Twin Block Appliance
This appliance has been shown to
produce increase in mandibular length
as well as a variation in lower anterior
facial height. Trimming of the
posterior bite blocks of the appliance
facilitate the eruption of the lower
posterior teeth in patients with a deep
bite and increased Curve of Spee. It is
a full time wear appliance and
speaking is not a problem. Active
phase of 6-9 months followed by a
supportive phase of 3-6 months for
molars to erupt into occlusion.
Average treatment time is 18 months
including retention period.

Related articles:
1.Keeling et al:
Reveal that both bionator and head-gear treatments corrected Class II molar relationships, reduced
overjets and apical base discrepancies, and caused posterior maxillary tooth movement. The skeletal
changes, largely attributable to enhanced mandibular growth in both headgear and bionator subjects,
were stable a year after the end of treatment, but dental movements relapsed.
(Am J Orthod Dentofacial Orthop 1998;113:40-50.)
2.Ghafari et al – comparison of head gear Vs Frankel in early treatment of Class II div 1
malocclusion – Randomised Clinical trial
The results indicate that both the headgear and function regulator were effective in correcting the
malocclusion.A common mode of action of these appliances is the possibility to generate differential
growth between the jaws. The extent and nature of this effect, as well as other skeletal and occlusal
responses differ. Treatment in late childhood was as effective as that in midchildhood. This finding
suggests that timing of treatment in developing malocclusions may be optimal in the late mixed
dentition, thus avoiding a retention phase before a later stage of orthodontic treatment with fixed
appliances. However, a number of conditions may dictate an earlier intervention in the individual
patient.
(Am J Orthod Dentofacial Orthop 1998;113:51-61.)

3.Treatment effects of the twin block appliance: A cephalometric study
Christine M. Mills, DDS, MS,a and Kara J. McCulloch, DMD
Vancouver, British Columbia, Canada, and Seattle, Washington
A clinical study was undertaken to investigate the treatment effects of a modified Twin Block
appliance. Results indicated that mandibular growth in the treatment group was on average 4.2
mm greater than in the control group over the 14-month treatment period. In addition, some
dentoalveolar effects in both arches contributed to the overjet correction. No statistically
significant increase in the SN mandibular plane angle occurred during treatment and, in general,
the magnitude and direction of the skeletal changes were found to be quite favorable. (Am J
Orthod Dentofacial Orthop 1998;114:
15-24.)

Early treatment
of
Class III Malocclusion

Frankel III Appliance
• It is a functional appliance
designed to counteract the
muscle forces acting on the
maxillary complex. According
to Frankel, the vestibular
shields in the sulcus are placed
away from alveolar buccal
plates of the maxilla to stretch
the periosteum and allow for
forward development of
maxilla. The shields are fitted
closely to the alveolar process
of the mandible to hold or
redirect growth posteriorly.

Ulgen et Firatili (AJO 1994) have found the best response to
Frankel III with an increased overbite of 4-5 mm in early
mixed dentition. It is more successful in patients with class III
malocclusion presenting with a functional shift on closure.

Chin cup therapy
• The main objective is to
provide growth inhibition or
redirection and posterior
positioning of mandible.
Most studies recommend an
orthopaedic force of 300 to
500 g per side (AJO 1987).
Patients are instructed to
wear the appliance 14
hrs/day. A force is usually
directed through the condyle
or below the condyle.

Sugawara et al (AJO 1990) have compared the
growth changes of patients after chin cup treatment with
control subjects and reported that at age 17 the mid-face is
more deficient in patients of control group than in those of
treatment group.

Protraction Facemask
•Consists of a fore head pack and
a chin pad that are connected with
a heavy steel support rod. A
crossbow is connected to support
this rod to which area attached
rubber bands to produce a forward
and downward elastic traction on
the maxilla.
• The mask system introduced by
Mcnamara in 1987 as a bonded
RPE in addition to a facial mask
and elastics.

•Protraction with expansion can also be done using
a banded palatal expander, a quad helix, etc.
•McNamara reports that the optimal time to
intervene in an early class III patient is at the time
of initial eruption of the upper central incisors.

CONCLUSION
Most patients who receive orthodontic care
in mixed dentition will need a second phase
of treatment in permanent dentition. Whether
to render treatment in the mixed dentition
requires careful case selection and a through
diagnosis and treatment plan.

Benefits of Early class II Treatment : Progress Report of a Two face randomized Clinical Trial
J.F.CamillaTulloch
We conclude that, for children with moderate to severe Class II problems, early treatment followed by
later comprehensive treatment on average does not produce major differences in jaw relationship or
dental occlusion, compared with later one-stage treatment. The severity of the initial problem and the
treatment time, surprisingly, are not important influences on the final outcome. Variability in skeletal
growth pattern appears to be a major contributor to variability in treatment response. Differences in
patient compliance, clinician proficiency, and, probably, other (yet-unidentified) clinical factors also
must affect treatment outcomes. It is likely that the indications for early treatment can be refined in the
future to permit better selection of those patients most likely to benefit from this type of intervention.
(AJO Jan 1998)

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