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1. A SEMINAR ON
FRANKEL FUNCTIONAL
REGULATOR

2. CONTENTS.
1. INTRODUCTION.
2. HISTORY.
3. SYNONYMS.
4. PHILOSOPHY.
5. INDICATIONS & CONTRAINDICATIONS.
6. ADVANTAGES & DISADVANTAGES.
7. DIAGNOSIS.
8. TYPES.
9. MODIFICATION.
10.TREATMENT OBJECTIVES.
11. CLINICAL HANDLING
12.INSTRUCTIONS.
13. JOURNAL REVIEW
14.CONCLUSION.

3. INTRODUCTIONINTRODUCTION
 Functional appliances areFunctional appliances are
defined as loose fitting ordefined as loose fitting or
passive appliances whichpassive appliances which
harness or eliminatesharness or eliminates
natural forces of the oro-natural forces of the oro-
facial musculature thatfacial musculature that
are transmitted to theare transmitted to the
teeth and alveolar boneteeth and alveolar bone
through the medium of thethrough the medium of the
appliance .appliance .

4. The basis of functional treatment in general is the principle
that a “new pattern of function” dictated by the appliance ,
leads to corresponding “new morphologic pattern”.
INTRODUCTION…..

5. The functional regulator is a removable orthodontic appliance
developed by Professor Rolf Frankel .
This appliance is used during the mixed and early permanent
dentition stages to effect changes in anteroposterior, transverse,
and vertical jaw relationships.
 The Frankel appliance, as it is more commonly termed, has
two main treatment effects.
First, it serves as a template against which the craniofacial
muscles function.
The second effect of the Frankel appliance is its influence on
skeletal and dental development
INTRODUCTION….

6. HISTORYHISTORY
IIn 1880,n 1880, KingsleyKingsley introduced the term and conceptintroduced the term and concept
ofof "jumping the bite""jumping the bite" for patients with mandibularfor patients with mandibular
retrusion.retrusion.
 RobinRobin in 1902had created an appliance quitein 1902had created an appliance quite
similar in its objectives; The monobloc.similar in its objectives; The monobloc.
Impressed by Kingsley's concepts and appliances,Impressed by Kingsley's concepts and appliances,
Viggow AndresenViggow Andresen in 1908 developed activator.in 1908 developed activator.
 Frantisek KrausFrantisek Kraus of Prague used oral screen toof Prague used oral screen to
interrupt abnormal muscle force resulting frominterrupt abnormal muscle force resulting from
thumb or tongue sucking .thumb or tongue sucking .

7. HISTORYHISTORY
Growth guidance was a vague concept before
Frankel’s contribution.
 Charles Nord was correct when he called the
Frankel method a, “revolution in orthodontic
appliances ”.
 Then Rolf Frankel of Germany developed an appliance in
about the middle of this century, which was not only
inhibitory but influence function in a more positive way .
This initial appliance was just two buccal shields ,
connected by wires without any clasp .

8. Synonyms:
 Frankel appliance
 Vestibular appliance
 Oral gymnastic appliance
 Functional regulator
Frankel postulates that the increase in crowding is the result of
hypertonic muscles in the buccinator mechanism restricting the
lateral growth of the teeth and their supporting tissues. One
objective of the vestibular shield is to regulate the hypertonic
muscles of the buccinator and perioral muscles, thereby giving
rise to the name functional regulator.

9. PHILOSOPHY OF FRANKEL APPLIANCE
1.Vestibular arena of operation
Frankel appliance is confined to the oral vestibule
and holds away, The buccal and labial musculature from the
dentition in those areas in which the pressure on the dento
alveolar structures has restricted the outward development of
these Structures.
Dentition is heavily influenced by
1)Functional matrix.
2)The buccinator mechanism.
3) Orbicularis Oris complex.

10. Functional matrix concept of Melvin Moss:
Buccal shields of frankel directly alter the soft tissue
configuration, increasing the oral volume, that is the capsular
matrix that allows the muscle to exercise and adapt and
improve.
The impact of the space increase on the basal development of
mandible has been suggested.
The term translative growth gives a new credence to the
theoretic and therapeutic aspect of orthopedic treatment with
frankel.

11. The functional matrix and
the Frankel appliance,
OO , Obicularis oris.
B, Buccinator. PMR,
Pterygomandibular raphe. SPC,
Superior pharyngis constrictor.
LP, Labial pad. VS, Vestibular
shield. The functional regulator
provides a larger functional
matrix than the teeth. The
buccinator mechanism will
grow and adapt to whichever
functional matrix (soft-tissue
capsule) is present in the
mouth. This adaptation occurs
primarily during growth. After
growth is complete, very little, if
any, change can be expected.

12. SCREENING EFFECT OF THE BUCCAL SHIELDSSCREENING EFFECT OF THE BUCCAL SHIELDS
Buccal shields and lip pads effectively holds the buccal and
labial musculature away from the dento -alveolar complex
eliminating the restrictive effect of the structures.

13. 4. Buccal shields , lip pads and periosteal pull.
There will be an outward periosteal pull by
maximum extension of the shields And pads into the depths
of buccal and labial vestibule to the point at which the
depth of the sulcus is under tension .
3. Differential eruption guidance.
By being free of the mandibular teeth selective
eruption of the lower posterior teeth is possible which
corrects vertical dimension deficiencies.
2 . Sagital correction via tooth borne maxillary
anchorage
Forward posturing of the mandible is achieved by
an acrylic pad that contacts alveolar bone behind the
alveolar segment.

14. 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.

15. 5)Postural behaviour of muscles .
There is considerable evidence that
postural disorders of the orofacial musculature play a
significant role in the causation of dento facial
disharmony . The aim of frankel appliance is to identify
the faulty performance of orofacial musculature and to
correct it by orthopedic exercises. Therefore frankel
appliance is an effective muscle trainer of the orofacial
musculature.

16. 6)Condylar growth
The anterior repositioning of the mandible
implies on alteration in the TMJ area. .Thus at right age ,
condylar growth can be successfully stimulated.

17. INDICATIONS:
 AGE GROUP OF 8-10 YEARS (MIXED DENTITION
PERIOD)WITH GROWTH SPURTS.
SKELTAL CL II MALOCCLUSION WITH PROGNATHIC
MAXILLA AND RETROGNATHIC MANDIBLE.
FUNCTIONAL CL II MALOCCLUSION.
IN A HORIZONTAL OR NETURAL GROWTH VECTOR CASE.
 CL III MALOCCLUSIOS.
BIMAXILLARY PROTRUSION AND OPEN BITE PROBLEMS.
FUNCTIONAL RETRUSION , DEEP OVER BITE , AND
EXCESSIVE INTEROCCLUSAL PROBLEMS WITH A
NORMALLY POSITIONED MAXILLAE.

18. CONTRAINDICATIONS
 Class I MALOCCLUSION WITH SEVERE
CROWDING
 THUMB SUCKING HABIT.
 SEVERE DENTOALVEOLAR PROBLEMS IN
PERMANENT DENTITION.
 UNCOPERATIVE PATIENTS.

19. 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.

20. DISADVANTAGES:
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.

21. DIAGNOSIS:
VISUAL TREATMENT OBJECTIVE DIAGNOSTIC
TEST
> The VTO for FR therapy is a simple but important
clue as to the efficiency of the FR appliance in any clinical
case .
> It is a functional test , that also helps to establish
whether a patient can tolerate a protrusive bite, as well as
whether satisfactory esthetic improvement occurs. The
patient is asked to posture the mandible forward to the
correct sagital relationship. If the outcome of the VTO test
is positive, the patient can be adjudged suitable for the
Frankel therapy.
However a proper cephalometric analysis is the
correct way to determine whether FR is the appliance of
choice.

22. Visual treatment objective:
Class II div I with
full occlusion
6mm of cuspal
advancement into
class I relation
After VTO

23. 1. Precise registration of the postural rest position
in natural head posture.
2. Path of closure from postural rest to habitual
occlusion.
3. Pre-maturities, point of initial contact, occlusal
interferences, and resultant mandibular
displacement .
4. Sounds such as clicking and crepitus in the TMJ.
5. Interocclusal clearance or freeway space.
6. Respiration .
Functional analysis.

24. • Enables clinicians to identify the craniofacial
Morphogenetic pattern, direction of growth.
• Differentiation between position and size of jaw
bases.
• Morphologic peculiarities.
• Axial inclination & position of the maxillary and
mandibular incisors
Cephalometric analysis:

25. TYPES OF FRANKEL APPLIANCE:
TYPES USES
1)FR 1 ---- CL 1 AND CL 2 DIV 1 MALOCCLUSION.
A)FR1a ---- CL 1 MALOCCLUSION WITH MINOR
CROWDING
CL I WITH DEEP BITE.
B)FRI b ---- CL 2 DIV 1 MALOCCLUSION WITH OVERJET
LESS THAN 5 mm.
C)FRI c ---- CL2 DIV 2 MALOCCLUSION WITH OVERJET
MORE THAN 7mm.
2)FR 2 ---- CL 2 DIV 1 AND DIV 2 MALOCCLUSIONS.
3)FR3 ---- CL 3 MALOCCLUSIONS.
4) FR4 ---- OPEN BITE ANDBIMAXILLARY PROTRUSION.
5)FR 5 ---- HIGH MANDIBULAR PLANE AND VERTICAL
MAXILLARY EXCESS

26. FUNCTIONAL REGULATOR I
The FRI of Frankel has 3 modifications
a. FRI a
b. FRI b
c. FRI c
A . FRI a
uses
CL I malocclusion with mild to moderate crowding
CL I deep bite cases .
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

27. 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.

28. 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.

29. 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.
Component parts:
Lower lingual support wire.
3 components soldered together or 1 continuous wire.
Wire member follows the contours of the lingual apical base

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

31. 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.

32. 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.

33. 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.

34. 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.

35. 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.

36. 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.

37. FR II
USES
They are used for the treatment of CLII div I and II
malocclusions. They are the most widely used.
COMPONENTS
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.

38. CONSTRUCTION
The steps are
1. separators.
Recommended 1 week before taking the impression. Placed between
maxillary canine and first deciduous molars or first molar embrasure.
The slicing mechanism allows immediate seating of the appliance.
:

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

40. 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. Before taking the construction
bite, the clinician must prepare by making a detailed study of
the plaster casts, cephalometric and pan oral head films, and
the patient's functional pattern.
3.Constuction bite.

41. .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.

42.  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.
 In the frankel technique construction bite is not open
any more than needed to allow the cross over wires to pass
through the interdental space. It is necessary for effective lip
seal exercises
Construction bite……

43. 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 .

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

45. 7. 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 is determined individually by the amount of desired
expansion needed. 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

46. 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.
.

47. 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 .

48. Lingual stabilizing bow.
• Improved structural support and gives stability to the
maxillary arch.
• 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 .
• Its Objective of preventing lingual tipping of the maxillary
incisors.

49. 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.

50. FR III
USE
Treatment of CL III malocclusions.
Lip pads
Situvated 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.

51. Buccal shields
Stands away some 3mm from maxillae Posterior dento alveolar structures.
They are in contact with mandibular teeth and the mandibular apical base
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.

52. Occlusal rests.
Occlusal shield 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.

53. 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).

54. 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.

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

56. FR IV.
USES
• Correction of open bite and bimaxillary protrusion.
• exclusively confined to mixed dentition
Components.
• Same vestibular configuration as FR I and II with no canine loops and
protrusion bows.
• There are four occlusal rests on the maxillary first molars, and first
deciduous molars to prevent tipping of the appliance.

57. 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. The 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.
MODE OF ACTION OF FR IV

58. 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 .

59.  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.

60. 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.

61. MODIFICATIONS
1. By H S ORTON ( JCO 1992)
> Vestibular shields have 3 -4mm less peripheral
extension than the conventional appliance.
Capped Frankel appliance.
> Lower labial capping – The lingual acrylic of FR II is
extended to cover the incisal 1/3 rd of lower
incisors and cuspids.

62. 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.
2. Modified function regulator
S. Haynes, Edinburgh, Great Britain

63. TREATMENT
OBJECTIVES
Frankel produces the following changes in the orofacial
complex.
1 .An Increase of sagital and transverse intraoral space.
2. An increase of vertical intra oral space.
3. Forward positioning of the mandible.
4. Muscle function adaptation.

64. 1. INCREASE IN INTRA ORAL SPACE.
 It is achieved primarily through buccal shields and lip
pads which eliminate the harmful mechanical forces on
the pressure sensitive membraneous structures.
 The constant outward pull that is exerted on the
connective tissue fibers and muscle attachments in the oral
vestibule is transmitted to the alveolar bone by the fibers
inserting into the periostium and bone. This aids in the
lateral movement.

65. 2. VERTICAL SPACE INCREASE.
 Increase of vertical intraoral space is possible because
the construction bite is taken, so that the bite is opened
in the posterior segments as the mandible is held
forward.

66. 3. MANDIBULAR PROTACTION.
The position of the mandible is changed through the
gradual training of the protractor and retractor muscles
followed by condylar adaptation.
The effect of the u loop and lingual plate on the
mandibular positioning through pressure sensation .

67. 4. MUSCLE FUNCTION ADAPTATION.
 Development of new patterns of motor function ,
improvement of muscle tones and establishment of proper
oral seal.
 The pads and shields massage the soft tissues improving
blood circulation .
 The pads and shields stretch the muscles in disto occlusion.

68. 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.
The appliance should be inserted with a slight rotatory
motion.

69. Treatment timing
Optimum time to start the treatment is the mixed dentition period.
(8 to 10 year age)
Wearing time
o Although the Frankel appliance will be worn all the time except for
the meals the treatment should be started slowly.
o For the first two2 weeks the appliance should be worn for 2 to 4
hours during the day.
o 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.
o The appliance and treatment progress should be checked at 4 weeks
interval.
An initial end to end molar relationship is corrected in 6 months.

70. SUCESSFUL TREATMENT CONSIDERATIONS.
1. PROPER IMPRESSIONS.
2. CONSTRUCTION BITE.
3. APPLIANC FABRICATION.
Patient and appliance management.
IMPORTANT PRECONDITIONS THAT SHOULD BE
EMPHASIZED.
1. RIGHT INDICATIONS FOR TREATMENT.
2. RIGHT PSHYCOLOGICAL INTRODUCTION OF APPLIANCE
3. COPERATION OF PATIENT AND PARENTS.

71. 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.

73. Frontal Facial Changes with the Frankel Appliance
Albert H. Owen.
ANGLE ORTHODONTICS 1988 MARCH
1. Edgewise treatment does not appear to increase the
mandibular width more than average growth without treatment.
2. Frankel treatment appears to increase the mandibular width
significantly more than either Edgewise or average growth. This
phenomenon is most likely due to the action of the vestibular
shields.
3. Frankel treatment tends to make the patient more
brachyfacial than average growth, as revealed by the frontal
facial taper angle.

74. 4. Brachyfacial individuals appear to have more ideal
occlusions ( PLATOU AND ZACHRISSON (1983)28, and
perhaps have better stability than less brachyfacial
individuals.
5. Brachyfacial faces are more common among models,
movie stars, and beauty contest winners than dolichofacial
faces, suggesting that brachyfacial individuals have more
pleasing esthetics than more narrow-faced people.
6. Untreated Class II individuals do not appear to grow as
wide as untreated Class I individuals. The reason for this is
unknown.

75. The potential improvements have been presented, and
their coordination into a multibanded practice seems
possible. Whatever results are lacking after treatment with
functional appliances could be perfected with fixed
appliances of the clinician's choice.
 The possibility of reducing the need for extractions,
reducing the time needed for multibanded treatment, and
improving the facial results seems to be great enough to
justify further investigation of this appliance as to achieving
predictable changes.
Morphologic changes in the sagital dimension
using the Frankel appliance – Owen
AJO 1981 Dec

76. Sixty treated and forty-seven untreated Class II, Division 1
patients were examined in this study. The patients in the
former group were treated with the functional regulator of
Frankel (FR-1 or FR-2), while patients in the latter group were
not treated but were of similar ethnic and skeletal
composition. Sequential dental casts of the treated and
untreated groups were examined, and the changes in lingual,
buccal, and alveolar arch widths were compared.
Arch width development in Class II patients treated
with Frankel appliance
McDougall, McNamara, and Dierkes
AJO 1982 Jul
Contd…

77. The expansion is not limited to a particular region of the
dental arch, although in absolute terms the largest expansion
values occur in the premolar and molar regions, while lesser
values were recorded in the canine region. In addition, this
study indicates that in the maxilla narrower arches tend to
expand more than wider arches.
The results of this study indicate that expansion of the
maxillary and mandibular dental arches and their supporting
structure occurs routinely when a functional regulator (FR-1
or FR-2) is conscientiously worn by the patient.