Frankel appliance

CONTENTS
◂ Introduction
◂ History
◂ Principles of functional regulator
◂ Indications and contra indications
◂ Advantages and disadvantages
◂ Types
◂ Clinical handling
◂ Modifications of FR
◂ References

INTRODUCTION
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◂ Functional appliance
◂ Loose fitting or passive appliance
which harness natural forces of the
oro-facial musculature that are
transmitted to the teeth & alveolar
bone through the medium of the
appliance

FRANKEL’S FUNCTIONAL REGULATOR
◂ Orthodontic device developed by Rolf Fränkel
(Zwickau) in 1961 in the form of a skeletonized
oral shield that, while not in contact with the
underdeveloped parts of the jaw, is intended to
bring about their development.
◂ Because the plate elements remain free,
the tongue is unhindered within the oral cavity so
that its shaping force can exert its full effect.
4

◂ At the same time, the lips are supported in the
region of the nasolabial and mentolabial fold
by frontal pads resulting in normalisation of lip
closure. After application of wires and screw
spindles, the functional regulator can also solve
individual problems such as gap openings and
malposition of individual teeth and groups of
teeth in a mechanical orthodontic manner.
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SYNONYMNS
◂ Encircle device
◂ Functional corrector
◂ Functional regulator
◂ Vestibular appliance
◂ Oral gymnastic appliances
◂ Orofacial orthopedic appliance
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Dr. Rolf Frankel (1908-2001)
◂ From town Leipzig, East Germany
◂ In the early 1960’s-wrote of his
functional appliance development.
◂ Frankel drew form the concept of
mandibular forward posturing plus
the oral screen
◂ Frankel designed the appliance to be
worn full time called functional
regulator or frankel appliance.
9

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The factors that inspired Frankel were:
◂ Bulkiness of the appliance
◂ Gross demand for patient co-operation 😭
◂ Inability to control individual tooth
movements
◂ Inordinately lengthy treatment
◂ Partial results 😒
◂ Unsupported claims of significant
expansion

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◂ His contributions attracted little attention as
contributions were mainly in German.
◂ This changed later, as Dr. Frankel, learnt English
and translated it
◂ Dr. T.M. Graber invited him to the U.S. to present
his philosophy and treated cases and also
recognized his significant contributions.

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Concept was not new…
◂ 1892-WOLF-Transformation law "Soft tissue
shapes hard tissue"
◂ 1895–ROUX- Law of functional adaptation:
"Function is dependent on the functional
demand, morphology is function become form"
◂ The term "functional orthopaedics" goes back to
Roux

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◂ 1954 – BALTERS- Considered the "space
function" important for orofacial
development
◂ 1968/1969 – MOSS- Concept of
the "functional matrix":
Cranial development is not subject to direct
genetic control but is induced by the
'functional matrix' (theory is controversial).

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◂ 1970/1972/1983 - VAN LIMBORGH‘
Epigenetic regulation': principle of
induction, familiar from embryology

EQUILIBRIUM THEORY
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◂ A stationary body subjected to unequal
forces.
◂ From this perspective, we can say the
dentition is in equilibrium, when the muscle
forces of the tongue and those forces of the
lips and cheeks are balanced except under
certain cases of muscular imbalances.

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Vestibular area of
operation
Sagittal correction
via tooth borne
maxillary anchorage
Differential eruption
guidance
Minimal maxillary
basal effect
Periosteal pull by buccal shields
and lip pad

Vestibular area of operation
◂ Shields of the appliance extend to the
vestibular and this prevents the
abnormal muscle function.
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Sagittal correction via tooth borne
maxillary anchorage
◂ Appliance is fixed on the upper arch by
grooves mesial to the 1st permanent
molar and distal to the canine in the
mixed dentition period. –
◂ Presence of the lingual pad acts as
stimulator and helps in the forward
posturing of the mandible.
19

Differential eruption guidance
◂ Frankel is placed on the upper teeth. -
Mandibular posterior teeth are free to
erupt and their unrestricted upward and
forward movement contributes to both
vertical as well as horizontal correction of
the malocclusion.
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Minimal maxillary basal effect
◂ Downward and forward growth of
maxilla seems to be restricted, even
though lateral Maxillary expansion in
seen.
21

Periosteal pull by buccal shields and
lip pad
◂ Presence of buccal shields and lip pads
exert the periosteal pull which helps in
bone formation and lateral expansion of
the maxillary apical base.
22

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MODE OF ACTION OF FR
1. Increase in transverse and sagittal
direction - by use of buccal shields and
lip pads.
2. Increase in vertical direction - by
allowing the lower molar to erupt freely
because appliance is fixed to the upper
arch

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3. Muscle adaptation
◂ Development of new patterns of motor function
by buccal sheilds and lip pads of FR can b
achieved by
a) massaging the soft tissues
b) loosening the tight muscles
c) Improving the blood circulation
d) improving muscle tonicity
e) Providing new functional matrix for peri oral
muscle to act upon it- ‘Ought-to-be matrix’

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4. Mandibular forward positioning-
Position of mandible can be changed
by gradual training of the protractor
and retractor muscles followed by
condylar adaptation

INDICATIONS AND
CONTRA INDICATIONS

INDICATIONS
 Mixed dentition period with growth spurts.
 Skeletal class II malocclusion with prognathic
maxilla and retrognathic mandible (Positive VTO)
 Functional class II malocclusion.
 In a horizontal or neutral growth vector case.
 Class III malocclusions.
 Bimaxillary protrusion and open bite problems.

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CONTRA INDICATIONS
 Class I malocclusion with severe crowding
 Thumb sucking habit.
 Severe dentoalveolar problems in
permanent dentition.
 Uncoperative patients.

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ADVANTAGES
1. It enables elimination of abnormal muscle
function thereby aiding in normal
development.
2. Treatment can be initiated at early age .
3. Less chair side time is spent.
4. The frequency of the patients visit is less.
5. They do not interfere with oral hygiene status.
6. Duration of treatment is comparatively less.
they deal with skeletal as well as dent alveolar
problems.

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1. The appliance is bulky and the cooperation of
the patient is essential.
2. They cannot be used in adult patients were the
growth has ceased.
3. Cannot be used to bring about individual tooth
movement and in cases of crowding.
4. Fixed appliance therapy may be required at the
termination of treatment for final detailing of
the treatment.
DISADVANTAGES

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COMPONENTS
ACRYLIC
BUCCAL SHEILD
LIP PADS
LOWER LINGUAL PAD
WIRE
PALATAL BOW
LABIAL BOW
CANINE EXTENSION
UPPER LINGUAL WIRE
LINGUAL CROSS OVER WIRE
SUPPORT WIRE
LOWER LINGUAL SPRINGS

BUCCAL SHEILD
◂ They should extend deep into the sulcus,
particularly in the apical region of maxillary first
premolar and maxillary tuberosity.
◂ The shield must be at an appropriate distance
from the lateral aspect of the teeth and alveolus
for expansion. The thickness of the shield should
not exceed 2.5mm in order to make the wearing
of the appliance comfortable.
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PURPOSE OF BUCCAL SHEILD
1. To restrain the cheek musculature
2. The action of the tongue, acting from within
the oral cavity brings about an expansion of
the dental arches
3. The sheilds -first premolar and maxillary
tuberosity area- stretches the periosteum -
cause tension -deposition of bone along the
lateral aspects of maxilla

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◂ The vestibular shield creates tension at
the depth of the mucobuccal fold in a
lateral direction.
◂ This tension is directed at influencing the
erupting permanent teeth to erupt
further laterally than normal, thereby
resulting in arch expansion.
◂ Notice that less influence is seen on fully
erupted teeth, as shown by the open
arrow.

LABIAL PAD
◂ These pads are rhomboid in shape .
◂ In crossection they should be tear drop in
shape.
◂ The upper edges of the lip pads should
be at a distance of 5mm from gingival
margin.
◂ The distal edge should not overlap the
labial protuberance of canine root 37

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Operational purpose:
◂ The lip pads when correctly positioned in
depth of sulcus,have a supporting effect on
lower lip smoothing the mentolabial sulcus
and improving lip posture.
◂ Thus the lower lip makes a normal contact
with the upper lip which is important for
establishment of competent lip seal.

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Forced training:
◂ The main purpose of lip pads is to prevent
hyperactive mentalis muscle
◂ This inhibitory action is necessary in order to
achieve a training effect on lip muscles which
are designed to bring about physiological lip
seal.

LOWER LINGUAL PAD
◂ It lies lingually below the gingival margin of
mandibular teeth and extends distally to the roots of
lower second premolar.
Operational Purpose:
◂ Forced Training: It is used to overcome poor
postural performance of muscles suspending the
mandible
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• It originates in the central groove of maxillary first
molar forming an occlusal rest that is parallel to
the occlusal plane so as to allow expansion of
molars laterally.
• The wire makes a loop in the buccal shield and
recurve to cross in the interproximal groove
between maxillary second premolar and first
molar.
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◂ The wire then crosses the palate with a
posterior curve that approximates between
hard and soft palate. From there it recurves in
a similar manner.
◂ It is constructed by 1mm gauge of wire.
◂ It is used for posterior appliance stability and
intermaxillary anchorage. 43

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• Canine loop is embedded in the buccal shield
at the level of the occlusal plane.
• It rises sharply to the gingival margin of
maxillary first deciduous molar, and fits in
the embrasure between the deciduous first
molar and the canine to lock the appliance in
place on the maxilla.

• The loop wraps around the lingual
surface of the canine and emerges
labially in the canine-lateral incisor
embrasure, curving distally over the
canine cusp.
• The free end can be bend 46

◂ In the mixed dentition stage the wire
embedded in the acrylic can be adjusted to
prevent interference with the proper
eruption of the canine and first premolar.
◂ It is fabricated by 0.9mm gauge of wire.
◂ It helps in canine guidance and proper
stabilization of the appliance.
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LABIAL BOW
◂ It operates as a “function-activated “ element i.e. it
transmit forces generated by the orofacial muscles on
the teeth.
◂ The labial wire turns gingivally at right angle between
the maxillary lateral incisors and canine to form the
canine loops.
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◂ They are fabricated by 0.9mm gauge
of wire.
◂ It supports the lip pads in proper
position.
◂ The average distance between the
labial wires embedded in the lip pads
and gingival margin is 7mm.
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◂ Three wires are used for fabrication of
labial wires.
◂ The central wire is bend in the shape
of inverted “V” and must be high
enough to prevent irritation of labial
frenum. 51

• Lateral wire emerges from the buccal shields
in slightly inferior direction approximating
the middle of canine root, about 1.5mm away
from mucosal surface to prevent gingival
laceration. Lateral wire ends at lateral incisor
embrasure.
• Lateral wire are positioned 0.75mm away
from wax relief in order to ensure that they
will be firmly embedded in the future buccal
shield. 52

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• The central wire is used to reinforce the
lingual shield at the midline in order to
prevent breakages.
• It follows the contour of lingual apical base
at approximately 1mm to 2mm from the
mucosa and 3mm to 4mm below the lingual
gingival margin of incisors, to allow the
addition of the acrylic.

◂ It is fabricated by 0.8mm gauge of wire.
◂ Three pieces of wires are used for fabrication.
◂ Two lingual springs emerges from the
lingual shield occlusally and are contoured
to the lingual surface of the lower incisors
right above the cingulum of the lower
incisors. 55

• In the treatment of deep bite, they can be bend
inferiorly to open the bite and allow the buccal teeth
to erupt.
◂ If they are to be used as “function-activated” element
they may be placed on the lingual surface of lower
incisors superior to the cingulum.This should only be
done in severely tipped lower incisors.
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◂ The lingual contour of the wire is positioned
1mm away from the mucosa. It should run
posteriorly , and the free ends, about 9mm to
10mm below the lingual gingival margin ,are
then bend at right angle to secure a firm seat
in the acrylic.
• It is important that the wire pass
interocclusally without contacting upper and
lower teeth. 58

• They are then bend laterally to insert in buccal
shield.
• The lateral end of the wire are parallel to the
occlusal plane because they will be used as guides
when lower anterior section of appliance is
advanced to change mandibular position step by
step.
• For this purpose the portion of the wire
embedded in the acrylic should be straight so that
it can slide through the acrylic of the shield. 59

◂ Crossover wire passes between the occlusal
surface at the embrasure between the first
and second deciduous molars.
◂ It is fabricated by 1mm gauge of wire.
◂ Crossover wire connects the lingual shield
with the buccal shields.
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Clinical procedures
Visual Treatment Objective
Impression Making
Construction bite
Pre- Frankel appliance fixed/
removable mechanotherapy

Visual treatment objective
Class II Div 1 malocclusion 3mm of mandibular protraction 6 mm of mandibular protraction

Impression making
◂ Thermo sensitive tray or a custom fabricated
tray , with proper beading to improve details.
◂ Successful therapy depends on the fit &
comfort of the appliance
◂ Impressions should reproduce the whole
alveolar process to the depth of the sulci,
including maxillary tuberosities.

◂ Metal flanges of the tray should not reach too far into the
sulcus.
◂ Approx. 15mm from the bottom of the tray to the top is as
far as the tray should extend.
◂ Ideal impression-
 maximum extension vertically
 Minimum extension laterally & anterio-posteriorly

Construction bite
◂ Advancement only by 2.5-3mm
◂ Vertical opening only large enough to
allow crossover wires through the
interocclusal space without
contacting the teeth
◂ Anteriorly, not more than end-to-end
bite.

◂ “Step-by-step” activation produces a better and
more continuous tissue reaction, rather than the
“great leap forward”
◂ Histologic research by Petrovic confirms that
step wise correction of sagittal discrepancy is
more effective for both tissue response and
patient adjustment to the forward posturing.
◂ Many studies , one of Schmuth et al in 1995 notes
that patient can easily tolerate 4-6 mm of
advancement

Frankel uses an adapted
baseplate to which wax is
added and softened for
construction bite.
Leaves the anterior region
open to visualize midlines

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FR
FR I
FR I-a FRI-b FR I-c
FR II FR III FR IV FR V

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S.NO. CLASSIFICATION INDICATION
1 FR I Class I and Class II div 1 malocclusion
2 FR Ia Class I with deepbite, Class I with minor to
moderate crowding or arrested development of
basal arches
3 FR Ib Class II div 1- Overjet >5mm
4 FRIc Class II div 1- Overjet >7mm
5 FR II Class II div 1 and div 2
6 FR III Class III
7 FR IV Openbite
8 FR V Vertical maxillary excess+ high mandibular
plane angle in long face patients ( along with
headgear)

FR - I
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Used in treatment of class I and Class II division 1 malocclusion

Indications
◂ Angle class I and crowding
◂ Angle class II div 1 (distal occlusion)
with normal overbite or open bite
◂ Moderate labial inclination of the upper
incisors
◂ Underdevelopment of the apical
bases (primary crowding symptoms)
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› FR 1a : Used for class I malocclusions where
there is minor to moderate crowding and also in
class I deepbite cases.
› FR 1b : Used for class II division 1 malocclusion
where overjet does not exceed 5mm.
› FR 1c : Used for class II division 1 malocclusion in
which the overjet is more than 7mm.
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FRI a
Components
◂ Acrylic parts
◂ 1. Vestibular shields.
◂ 2. lip pads.
◂ Wire components:
◂ 1. Palatal bow.
◂ 2. labial bow.
◂ 3.Labial support wire.
◂ 4. Lingual bow.
◂ 5. Canine loops

Lingual bow
•In FR Ia a wire loop is used
instead of an acrylic lingual
pad that helps in the forward
position of the mandible
forward.
• It extends downward to the
floor of the mouth which fit
against the lingual tissue
below the incisors.

Palatal bow
Convexity facing distally with
lateral extensions crossing the
occlusal surface in the embrasure
mesial to the first molar.
Lip pads
It eliminates the hyperactive
mentalis activity.

FR I b
◂ Uses
◂ CL II DIV I with a deep bite and an over
jet of not more than 7mm.
◂ Wire forming
◂ Palatal bow 1.0mm wire is used
◂ Tooth moving wire 0.8 mm wire is
used.
◂ Lower lingual support wire.
◂ 3 components soldered together or 1
continuous wire.
◂ Wire member follows the contours of the
lingual apical base
◂

Lower lingual springs
Surface of the lower incisors right
above the cingula .
Lower labial wire
It supports the Skelton for the lip
pads .

Palatal bow
• It provides some extra wire length
to facilitate a lateral expansion
adjustment.
•The wire should cross the occlusal
surface in the embrasure Mesial to
the first molar.
•Locking of the appliance on the
maxillary arch is mainly due to this
insertion on the embrasure.

Labial bow
The bow originates in the
buccal shield and lies in the
middle of the labial surfaces of
incisors , turning gingivally at
right angles between maxillary
lateral incisors and canines.

Canine loop
The loop wraps around the lingual surface of the
canines .It is embedded in the buccal shield at the
occlusal plane level. It rises sharply to the gingival
margin
And fits in the embrasure.

Fabrication of the acrylic parts
• After wires are properly adapted to the
models they are secured with sticky wax.
Shields
• The total thickness of the shields and
pads should not be more than 2.5mm.
•The lingual surface of the shield should be
smooth.
Lip pads
• The upper edges of the lip pads should be
at least 5mm from the gingival margin.

FRI c
Uses
◂ In more severe CL II DIV 1
malocclusion in which the overjet is
more than 7mm and disto-occlusion
exceeds an end to end cusp relationship.
◂ It is seldom used.

Component parts
The buccal shields are split
horizontally and vertically into 2
parts –
Anteroinferio portion contains
the wires for lingual acrylic
pressure pad or shield and for the
lower lip pads. Vertical split is
opened to the desired position by
a 2 to 3 mm advancement and is
then filled with acrylic.

FR II
They are used for the treatment of CLII div I and II malocclusions. They are the most
widely used.
Acrylic components
a. buccal shields.
b. lip pads.
c. lower lingual pad.
Wire components.
a. palatal bow.
b. labial bow.
c. canine extensions.
d. upper lingual wire.
e. lingual cross over wire.
f. support wire for lip pads.
g. lower lingual springs.

CONSTRUCTION
The steps are
1. Separators.

Seating grooves in maxillary model for permanent dentition
Notching in the deciduous
dentition

2.. Impression
Very important clinical procedure so that impression reproduces
the whole alveolar process up to the depth of the sulci.

• The purpose of this mandibular manipulation
is to relocate the jaw in the direction of treatment
objectives.
•This creates artificial functional forces and allows
assessment of the appliance's mode of action.
3.Constuction bite.

 For minor sagital problems (2-4mm)
the construction bite is taken in an end to
end incisal relationship.
 Horizontal and vertical requirements.
 Construction bite should not move the
mandible forward further than 2.5 mm to
3mm .
 End to end incisal relationship or no
more than 6mm forward.
 Positioning the edge to edge contact
will determine the vertical opening.

 Frankel appliance design and
construction permits a further
advancement of the mandible after a
favorable response to the treatment from
the construction bite .
 Optimal prechondroblastic activity in
the condyle is observed by staged
construction bite.

4.Working model pour up and trimming.
Models should extend away from
the alveolar process at least 5mm to
permit application of wax.
5.Cast carving.
Casts are carved for
accommodating the buccal shield and
lip pads .

Trimming for buccal shields
◂ Sulcular depth must
be 10-12 mm above
the gingival margin
of the posterior
teeth
◂ Allows optimal
extension of the
buccal shields for all
possible apositional
growth
10-12 mm

Trimming for lip pads
Real depth of sulcus
Sulcus reproduced
in impressions
Adequate amount
of carving
Inadequate carving
• Prevents complete
extension of lip pads
into the sulcus
• Prevents periosteal pull
• Lip mucosa invaginates
into the space
 
Alveolar surface should
be nearly vertical
after carving.
Lowest border is 12 mm
from the gingival
margin
12mm 5-7 mm

6. Work model mounting .
mount the models on the straight line fixators.

Wax relief.
o Wax padding under the buccal shield to
establish space between the tissue and the
appliance.
o Wax is thicker in the maxillary sulcus than
in the mandibular sulcus
o Thickness should not exceed more than
3mm.
o Wax covering important in the region of
the first deciduous molar
o Waxing is done separately on maxillary
and mandibular cast and then joined together

Wax relief:
Maximum thickness of wax padding
under buccal shield for FR1
Wax padding under the buccal shield to
allow for dentoalveolar expansion

Wire forming
The FR II is modified by
adding a stainless steel protrusion
bow (0.8mm )behind the
maxillary incisors , which serves to
maintain the prefunctional
alignment and also stabilizes the
appliance.

Lingual stabilizing bow.
•It originates in the vestibular shield and
passes through the canine –first deciduous
molar embrasure.
• Wire forms loops that approximate the
palatal mucosa and recurve vertically to
contact the incisors at the canine lateral
embrasure.
• A 90 degree bend allows the wire to
follow the lingual contours of the four
incisors , right above the cingula .

Canine loops
 Originate in the buccal
shield but they embrace the
canine buccal instead of
lingually.
 By placing these wires
2 to 3mm away from the
canine the restrictive muscle
function is eliminated .

Fabrication of acrylic parts:
 Wires are bent and properly adapted to
the models and they are secured with sticky
wax .
 Buccal shields and lip pads and lingual
pads are fabricated in self cure acrylic.
Shields:
 Should extend to the vestibule.
 lingual surface of the shields should be
smooth.
Lip pads:
Upper edges of the lip pads should be at
least 5mm from the gingival margin.

FR III
Treatment of CL III malocclusions.
Lip pads
• Situated in the maxillary instead of the
Mandibular in labial vestibular sulcus.
•It eliminates the restrictive pressure of
the upper lip .
•To exert tension on the periosteal
attachments in the depth of the maxillary
sulcus, to stimulate bone growth.

Labial bow
• It extends across the six mandibular anterior
teeth just above the inter dental papillae.
•After a 90 degree bend downward at the distal
edge of the lower canine , another horizontal
bend is made approximately 5mm below the
gingival margin.
Buccal shields
•Stands away some 3mm from maxillae Posterior
dento alveolar structures.
•They are in contact with mandibular teeth and
the mandibular apical base

Occlusal rests
Occlusal rests originates in the
vestibular shield and is adapted to
lie in the occlusal fissure of the last
mandibular molar.
Palatal bow
• It pass directly distal to the last
molar tooth before inserting in the
buccal shields .
• It is capable of delivering a forward
force vector to the maxillary
dentition.

Mode of action:
The proposed method of action of
the FR-3 appliance. The distracting
forces of the upper lip are removed
from the maxilla by the upper labial
pads. The force of the upper lip is
transmitted through the appliance
to the mandible because of the close
fit of the appliance to that arch (after
Fränkel1).

Construction bite
The procedure of taking the
construction bite is done by retruding the
mandible as much as possible with the
condyle in its most posterior position.
The vertical opening is kept to a minimum
to allow lip closure with minimal stress.
Wax relief
No wax is applied to the mandibular
arch.

Fabrication of acrylic parts same as FR I and FR II.
Finished appliance

FR IV
• Correction of open bite and bimaxillary protrusion.
• Exclusively confined to mixed dentition

o As a result of treatment of these anomalies with the FR-
4 appliance and lip seal training, the growth and
development pattern of the mandible was altered.
oThe spontaneous downward and backward growth direction
of the mandible was changed to a upward and forward
direction by FR-4 therapy, allowing the skeletal anterior open
bite to be successfully corrected through upward and forward
mandibular rotation.
o
MODE OF ACTION OF FR IV

FR V
Modification of Frankel by Albert H Owen (1985 –JCO)
INDICATED- Long face syndrome having a high mandibular plane angle
and vertical maxillary excess .

 The appliance consists of addition
of posterior acrylic bite blocks
to arrest molar eruption.
 It also has head gear tubes that
accept a face bow for an occipital
pull headgear.

Advantages in
combination of frankel
with head gear.
1.The vertical dimension can be
decreased through intrusion of the
molars.
2.Increased mandibular growth.
3.Significant lateral expansion
may reduce the need for expansion.

Note palatal acrylic support and continuous
buccolabial acrylic construction, which
replaces conventional function regulator
with separate buccal shields and lip pads.
The appliance is not "locked" into the mesial
embrasure of the maxillary first molars by a
cross-palatal bar.
1.Modified function regulator
S. Haynes, Edinburgh, Great Britain

2.Capped Frankel appliance.
◂ Given by Raymond Otto in 1992
◂ Indicated in deep bite cases
◂ Controls labial tipping of mandibular
incisors
◂ Disadvantages
◂ Need of sufficient posterior
separation
◂ Capping may impinge on maxillary
incisors as treatment progresses
◂ Difficult to clean

3. HYBRID FUNCTIONAL APPLIANCE (FR 2 and
activator combination)
•Given by Dr. Peter Vig and Dr. Katherine Vig in 1986
•Hybrid appliances are specifically and individually tailored for
every patient.
•Problems of every patient is recognised and
•Instead of using a “named” appliance for the treatment of a class
of malocclusion, various components of different functional
appliances can be used to make a composite appliance.
•So, appliance designs that uniquely match the needs of individual
patients.

HYBRID FUNCTIONAL APPLIANCE (FR and
activator combination)
Buccal shield (one side)of an FR but maxillary posterior bite plane and
mandibular incisor capping like in an activator is used

CLINICAL HANDLING
OF THE
APPLIANCE

Stabilizing the appliance at the delivery is
absolutely essential
Pre placement, all margins are checked for
smoothness .
 Check vertical dimension.
 Over extension of the labial ,lingual, lip and
buccal pads causes tissue irritation . So the
extension should be correct.

Wearing time
 For the first two weeks the appliance should be
worn for 2 to 4 hours during the day.
 During the next 3 weeks the time is extended to 4 to
6 hours.
 it usually takes 2 months before the appliance is
worn at night.
 The appliance and treatment progress should be
checked at 4 weeks interval.
 An initial end to end molar relationship is corrected
in 6 months.

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Treatment timing
Optimum time to start the
treatment is the mixed dentition period.
(8 to 10 year age)

SUCCESSFUL TREATMENT CONSIDERATIONS.
 PROPER IMPRESSIONS.
 CONSTRUCTION BITE.
 APPLIANCE FABRICATION.
 PATIENT AND APPLIANCE MANAGEMENT.
IMPORTANT PRECONDITIONS THAT SHOULD BE EMPHASIZED.
1. RIGHT INDICATIONS FOR TREATMENT.
2. RIGHT PSYCOLOGICAL INTRODUCTION OF APPLIANCE
3. COOPERATION OF PATIENT AND PARENTS.

INSTRUCTIONS FOR THE PATIENT:
 A little discomfort is to be expected initially.
 Salivation may be increased but it should not be a problem.
 Outline the duration of wear expected.
 Instruction on appliance care and oral hygiene maintenance .
 Demonstrate the lip seal exercise .
 Ask the patient to speak a few words and reassure that speech would
normalize.
 Wearing time should be correctly followed.

Studies on Frankel’s
appliance

1. Mc Namara et al in 1985
Studied 100 patients treated with FR therapy and compared them with
untreated class II cases
• Greater mandibular growth development.
• Absence of maxillary growth changes
• Increase in lower facial height
• Greater vertical development of the mandibular molars
• Palatal tipping of the maxillary incisors,
• Labial tipping of the mandibular incisors
McNamara JA, Bookstein FL, Shaughnessy TG. Skeletal and dental changes following functional
regulator therapy on Class II patients. American journal of orthodontics. 1985 Aug 1;88(2):91-110

U
S
2. Falck F, Fränkel in 1989
• Studied 120 patients undergoing FR II
therapy
• 60 pts : stepwise advancement
• 60pts : single advancement
• Compared them with untreated class II
cases
• Significant increase in mandibular length
• Forward and downward rotation of
mandible.
• Increase in lower facial height.
• No relative changes in maxillary base.
• No significant difference when
advancement is done stepwise or at
once.
Falck F, Fränkel R. Clinical relevance of step-by-step mandibular advancement in the treatment of mandibular
retrusion using the Fränkel appliance. American Journal of Orthodontics and Dentofacial Orthopedics. 1989
Oct 1;96(4):333-41.

3. McNamara et al in 1990
•Studied 45 patients treated with Herbst appliance and 41 patients treated
with FR2 appliance.
•Compared cephalometric data with 21 untreated Class II cases.
Results :
•Both appliance influenced growth of craniofacial complex and showed
skeletal changes
•Both showed increase in mandibular length and lower facial height.
•BUT
•Greater dentoalveolar changes were seen in the Herbst group.
McNamara JA, Howe RP, Dischinger TG. A comparison of the Herbst and Fränkel
appliances in the treatment of Class II malocclusion. American Journal of Orthodontics and
Dentofacial Orthopedics. 1990 Aug 1;98(2):134-44.

4. Hamilton & Sinclair (AJO 1987) in a cephalometric,
tomographic and dental cast evaluation of 25 patients treated
with Frankel therapy reported
1.Treatment results were primarily dental, with little skeletal or condylar
alteration.
2.And NO head gear type restraining effect was seen in the maxilla.
-Hamilton SD, Sinclair PM, Hamilton RH. A cephalometric, tomographic, and dental cast
evaluation of Fränkel therapy. American Journal of Orthodontics and Dentofacial Orthopedics.
1987 Nov 1;92(5):427-34.

5. Janson et al (2003)
studied 18 patients undergoing FRII therapy for a period of 28 months.
• Statistically significant increase in the mandibular body compared to the
maxilla.
• Increase in lower face height which induced greater vertical development of the
mandibular molars
• Reduced the overjet and overbite
• Improvement in the molar relation.
• BUT
No changes in maxillary development,
No changes in the growth pattern.
Therefore it was concluded that the effects of the FR in the correction of
Class II malocclusions are primarily dento-alveolar, with a smaller
participation of skeletal changes.
Janson GR, Toruño JL, Martins DR, Henriques JF, De Freitas MR. Class II treatment effects of the Fränkel
appliance. The European Journal of Orthodontics. 2003 Jun 1;25(3):301-9.

Nielsen IL. Facial growth during treatment with the function regulator appliance. American journal of
orthodontics. 1984 May 1;85(5):401-10
5. Nielsen et al 1984
Facial growth was examined in ten patients who had completed one year of
treatment with the function regulator 2 (FR-2)
•Showed maxilla became retrognatic –or there was no changes in maxilla.
•No indications were found that FRII promoted forward growth of the
mandible.
•Changes were more in vertical plane
•Not necessarily improved the profile

References
•Dentofacial orthopedics with functional appliances .Graber,
Rakosi, Petrovic
•McNamara JA, Bookstein FL, Shaughnessy TG. Skeletal
and dental changes following functional regulator therapy on
Class II patients. American journal of orthodontics. 1985 Aug
1;88(2):91-110
•Falck F, Fränkel R. Clinical relevance of step-by-step
mandibular advancement in the treatment of mandibular
retrusion using the Fränkel appliance. American Journal of
Orthodontics and Dentofacial Orthopedics. 1989 Oct
1;96(4):333-41.

135
•McNamara JA, Howe RP, Dischinger TG. A
comparison of the Herbst and Fränkel appliances in the
treatment of Class II malocclusion. American Journal of
Orthodontics and Dentofacial Orthopedics. 1990 Aug
1;98(2):134-44.
•Hamilton SD, Sinclair PM, Hamilton RH. A
cephalometric, tomographic, and dental cast evaluation
of Fränkel therapy. American Journal of Orthodontics
and Dentofacial Orthopedics. 1987 Nov 1;92(5):427-
34.

•Owen 3rd AH. Modified function regulator for vertical maxillary excess. Journal of clinical
orthodontics: JCO. 1985 Oct;19(10):733-49.
•Vig PS, Orth D, Vig KW. Hybrid appliances: a component approach to dentofacial
orthopedics. American Journal of Orthodontics and Dentofacial Orthopedics. 1986 Oct
1;90(4):273-85.
•Haynes S. A cephalometric study of mandibular changes in modified function regulator
(Frankel) treatment. American Journal of Orthodontics and Dentofacial Orthopedics. 1986
Oct 1;90(4):308-20.

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