The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
00919248678078
2. INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com
www.indiandentalacademy.com
3. • INTRODUCTION
• SERVOSYSTEM THEORY OF FACIAL
GROWTH
• ACTION OF FUNCTIONAL APPLIANCES
• ESTIMATION OF CONDYLAR GROWTH
DIRECTION
• STUDIES ON FUNCTIONAL APPLIANCES
www.indiandentalacademy.com
4. INTRODUCTION
•
•
•
•
Major shift in the past 25 years
Multisystem environment
More than "straight teeth."
Changing of the specialty to Dentofacial
Orthopedics
• Teeth can literally be used as a handle to
manipulate facial changes
• Age-oriented therapy (i.e., early treatment)
• Literature is ambivalent
www.indiandentalacademy.com
5. INTRODUCTION
• Hamilton :Orthodontists are an interesting, complex
egocentric, 'almost' omniscient, quality oriented and
stubborn group
• 85 % agree and 7 % disagree alter the skeletal pattern
of a growing child,
• 74 % : earlier the correction of the skeletal problem,
the greater the chances of success and stability
• 25 % : European colleagues were more advanced in
growth guidance.
• 67 % : earlier orthodontics
• 72 % : prevent nonspecialist treatment and inroads by
pediatric dentists and general practitioners
• 71 % : patient compliance
www.indiandentalacademy.com
6. INTRODUCTION
• 78 % : simple biteplate maxillary constriction
mandibular entrapment
• 21 % : mandibular growth could be stimulated beyond
its natural potential.
• 59 % :condylar heads of the mandible and glenoid
fossa could be remodeled
• 96% : Maxillary expansion
• 85 % : airway problems
• 91 % : prolonged thumb or finger sucking and dummy
sucking
• 69% : tongue thrust and posture
• 80% : no causative relationship between functional
appliances and TMDs
www.indiandentalacademy.com
7. INTRODUCTION
• Correction of malocclusion, primarily by means of
controlled movement of the developing and
mature dentition into a desirable occlusal
relationship
• Control and modification of growth of skeletal
structures of the craniofacial complex, especially
via tooth borne appliances
www.indiandentalacademy.com
8. Historical perspective
• Genetic control theory:
inheritance and immutability of normal and
abnormal facial form
genotype supplies all information required
for phenotypic expression
www.indiandentalacademy.com
9. Historical perspective
• Late 1890s: Wolff’s law and Roux hypothesis:
changes in functional stress produced changes in internal
bone architecture and external shape
• Early 1900s: Pierre Robin: monobloc
passive positioning device
• Modified from bite jumping vulcanite maxillary guide
planes designed by Norman Kingsley (1880)
• Vorbissplatte: Hotz
www.indiandentalacademy.com
10. Historical perspective
• Viggo Andresen : Activator
• Lischer’s theory:
If abnormal musculature can exacerbate existing
malocclusions, can not the same muscles be used
to correct these problems?
• Andresen: modified Hawley type retainer with
lower lingual horse shoe flange
Significant sagittal basal bone and neuromuscular
improvement
www.indiandentalacademy.com
11. Historical perspective
• Initially not accepted in US:
facial growth could not be affected
tooth position can be altered with
appropriate appliances and biomechanics
www.indiandentalacademy.com
12. Theories of growth
• Genetic theory
• Sutural growth theory: Sicher (1947): growth at the
sutures results in growth of cranial vault and
downward and forward growth of the midface
• Cartilage directed growth theory:
Scott (1956): synchondroses, nasal septum and
mandibular condyle are centers of growth
www.indiandentalacademy.com
13. Theories of growth
• Functional matrix hypothesis:
Melvin Moss (1960)
• Craniofacial skeleton develops initially and grows in
direct response to its extrinsic, epigenetic
environment
• Functional matrix and skeletal unit
• “ Bones do not grow, bones are grown.”
(1972)
www.indiandentalacademy.com
Moss
14. Theories of growth
• Servosystem theory of craniofacial growth: Alexandre
Petrovic (1970s)
• 2 factors:
hormonally regulated growth of the midface and
anterior cranial base, which provides a constantly
changing reference input via the occlusion
ratelimiting effect of growth of the midface on the
growth of the mandible
www.indiandentalacademy.com
16. • Growth control involves a multitude of factors
• Interaction that occurs among them is often
highly important
• Local and regional extrinsic factors :tissue
contacts, muscles, blood supply and nerve
signals
• General factors :STH, somatomedin, thyroxine,
and sex hormones
www.indiandentalacademy.com
17. Petrovic 1977
• Demonstrate qualitative and quantitative
relationship between observed and experimental
findings.
• Broader understanding of orthodontic problems,
and action of appliances
• Familiarity of orthodontists with cybernetics
www.indiandentalacademy.com
18. Cybernetics
Transfer of Information
• Cybernetic systems operate through transfer of
information
• Physical, Chemical, Electromagnetic
www.indiandentalacademy.com
22. Closed Loop
Relationship maintained between input and output
Input
Comparator
Feedback
Loop
Transfer function
Output
www.indiandentalacademy.com
23. Regulation Type of Closed Loop
Input is constant
Any change of the input will initiate a “regulatory
process”
Input
Comparator
Regulation of input
www.indiandentalacademy.com
Transfer function
25. Components of a Servosystem
COMMAND
Reference Input Elements
Actuator, Coupling System,
Controlled System
COMPARATOR
Output
(Controlled Variable)
Central Comparator
(sensory engram)
Reference Input
Deviation Signal
www.indiandentalacademy.com
Performance
Analyzing
Elements
Performance
26. GROWTH OF THE FACE
ACCORDING TO THE
SERVOSYSTEM THEORY
www.indiandentalacademy.com
31. Role of Lateral Pterygoid and Retrodiscal Pad
•Blood Supply
•Bio-mechanic
www.indiandentalacademy.com
32. Relationship Between Lateral Pterygoid,
Retrodiscal Pad and Condyle
MENISCUS
LPM
RDP
www.indiandentalacademy.com
33. Stutzmann and Petrovic
Proper function of Lateral Pterygoid and
retrodicsal pad:
• Excision of Lateral Pterygoid
• Reduced function of the Retrodiscal pad
(Rat experiments)
www.indiandentalacademy.com
34. Elastic retrodiscal pad and its condylar attachment
• Predominant intermediaries between the
variations of LPM activity and the growth of
the condylar cartilage in rats and humans
• Direct, repetitive stimulation - same condylar
response as if the muscle were intact.
• Adequate blood supply and function are
essential.
www.indiandentalacademy.com
35. The Face as a Servosystem
Input – Maxillary dental arch
Output – Adjustment of the position of mandibular
dental arch
www.indiandentalacademy.com
36. Growth of the maxilla
Growth in
Length
Growth in
Width
www.indiandentalacademy.com
38. Growth in Length:
Traction
SeptoPremaxillary
ligament
Induction
Growth of
Nasal Septum
Biomechanical
Labio narinary
Muscles
Release of
STH
Somatomedin
Thrust
Growth of
Pre
Maxillary
extremity
Anterior shift
Of premaxillary
bones
Growth of
PremaxilloMaxillary
suture
Protrusion of
Upper Incisors
Increased size
Of Tongue
Thrust
Protrusion of
Lower Incisors
Direct Action
www.indiandentalacademy.com
Growth of
Maxillo
Palatine
suture
39. Growth in Width:
Growth of
Lateral cartilaginous
masses of Ethmoid
Release of
STH
Somatomedin
Transverse
Separation of
premaxillae
Outward growth
Of maxillary
bones
Growth of cartilage
B/w greater wings
& body of sphenoid
Increased size
Of Tongue
Outward shift of
Alveolus and
molars
www.indiandentalacademy.com
Direct effect
Growth of
inter Pre
Maxillary
suture
Transverse
Seperation of
Horizontal
Maxilla and
Palatine plates
Growth of
mid
Palatine
suture
Outward
Appositional
Bone
growth
40. The Face as a Servosystem
Release of
Hormones (Command)
LPM & RDP
(Coupling system)
Position of Maxillary
Dental arch (Ref Input)
Hormones
Growth at condyle
(Controlled System)
OCCLUSION
Output
Periodontium,
Teeth
Musculature
Joint
Actuating
signal
Actuator (Motor Cortex)
Brain
(sensory engram)
(Comparator)
Deviation Signal
www.indiandentalacademy.com
Mastication
(Performance)
41. Growth at the Posterior Border of the Ramus
www.indiandentalacademy.com
42. Variation in direction and magnitude of
condylar growth
Changes in the lengthening of the maxilla.
Resection of the nasal septal cartilage
Growth hormone
Testosterone
Orthopedic appliances
www.indiandentalacademy.com
44. Subperiosteal ossification rate and alveolar bone
turnover
• increased in anterior growth rotation
• decreased in posterior growth rotation
parallels the condylar cartilage growth rate
greater responsiveness to orthopedic and
orthodontic appliances in cases of anterior
growth rotation
www.indiandentalacademy.com
45. Other Terms Related to a Servosystem
Gain
=
Output
Input
Enhancement (Gain>1)
Attenuatation (Gain <1)
1. Large amounts of
TESTOSTERONE
2. Small or large amounts of
2. Small amounts of
OESTROGEN
TESTOSTERONE
3. Large amounts of
3. Very small amounts of
CORTISONE
OESTROGEN
1. STH – Somatomedin
www.indiandentalacademy.com
46. Attractor
Cusp to fossa relation
Repeller
Cusp to cusp relation
Disturbances
Abnormal tooth position
Occlusal interferences
Arthritis
Muscle Inflammation
Periodontitis, Pulpitis
www.indiandentalacademy.com
48. Peripheral Comparator
Before development of Occlusion:•Sensory engram not developed
•Servosystem does not operate
•Genetic influence on mandibular
growth
•Anodontia
After Development of Occlusion:•Sensory engram forms
•Peripheral comparator controls
growth
www.indiandentalacademy.com
49. Failure of Servosystem to Control Growth
• Peripheral comparator faulty – Caries,
Mutilated dentition.
•Discrepancy between rotation pattern (Anterior
or Posterior) and location of comparator.
www.indiandentalacademy.com
52. Most often in patients between 8-10 yrs old
Mixed dentition therapy is thus strongly
supported biologically.
www.indiandentalacademy.com
53. Importance of Discontinuities
•Growth prediction , treatment planning , decision making
•Stability of occlusion after it is established
•Genotype does not directly influence the phenotype
www.indiandentalacademy.com
54. Functional appliances
Place the mandible in a forward postural position
Increase the condylar cartilage growth rate and amount.
Sagittal deviation produced by the functional appliance decreases
thro the supplementary forward growth of the mandible
Deviation signal simultaneously decreases
Supplementary growth rate of the cartilage and the lengthening of
the mandible also decreases
www.indiandentalacademy.com
55. Periodic increase in the thickness
Increases in LPM and RDP activity
Increase in the rate and amount of condylar
cartilage growth
www.indiandentalacademy.com
56. • Appliance is removed after the growth is
completed - little or no relapse
• Removed before growth - no significant
relapse is detected if a good intercuspation is
achieved during the experimental phase
• If a good intercuspation is not achieved comparator of the servosystem imposes an
increased or decreased condylar growth rate
until a state of intercuspal stability is
established
• No genetically predetermined final length of
the mandible has been detected in these
experiments.
www.indiandentalacademy.com
58. The Sensory Engram
• Collection of feedback loops
• Blueprint of ideal muscular function/position
• CNS tends to operate along these feedback loops
www.indiandentalacademy.com
59. Optimality of Function
•Minimum deviation signal
•CNS always tries to revert back to optimal position
www.indiandentalacademy.com
60. For every unit of Growth hormone released,
the amount of growth in the maxilla is less than
in the mandible.
www.indiandentalacademy.com
62. Functional appliance
Increased contractile activity of the LPM
Intensification of the repetive activity of the retrodiscal pad (bilaminar zone)
Increase in growth-stimulating factors
-Enhancement of local mediators
-Reduction of local regulators (factors having negative feedback effects on cell
multiplication rate)
-Change in condylar trabecular orientation
-Additional growth of the condylar cartilage
-Additional subperiosteal ossification of the posterior border of the mandible.
Supplementary lengthening of the mandible
www.indiandentalacademy.com
63. Two Types of Functional Appliances:
) Activator, Postural hyperpropulsor, Frankel
appliance, Twin block, Bionator, Class II Elastics(?)
) Herren activator, LSU activator, Harvold-Woodside
activator, Extra oral traction on the mandible.
www.indiandentalacademy.com
64. FIRST GROUP:
Position mandible
Forward
Increased activity of
LPM and RDP
Less fatigable fibres in LPM
•Oudet et al (1988)
•Carlson et al (1990)
LPM “helped to contract more” by
Functional appliances.
www.indiandentalacademy.com
68. Functional appliances (especially Class II elastics)
Increased activity of RDP
Increased nutrients and growth factors supplied
and inhibitors removed.
Increased mitoses and earlier hypertrophy of
chondroblasts.
www.indiandentalacademy.com
70. Cytoplasmic junctions between skeletoblasts reduce.
Transmission of inhibitory factors reduce.
Increased mitotic rate and rate of differentiation into
prechondroblasts.
www.indiandentalacademy.com
71. SECOND GROUP:
Position mandible forward , open in beyond rest
position.
No increase in activity of LPM
•Herren (1953)
•Auf der Maur (1978)
Yet there was an increase in growth
www.indiandentalacademy.com
72. wo steps:
) While appliance is worn:Forward position
Reduction of length of LPM
New sensory engram
) While appliance is not worn:New sensory engram
Functioning in anterior position
Increased activity of RDP
www.indiandentalacademy.com
73. Action of first group
while appliance is worn
Action of second
while appliance is not worn
group
www.indiandentalacademy.com
74. CLINICAL IMPLICATIONS
1) Principle of optimality of function :Less relapse tendency if post orthodontic
treatment muscular activity produces a lower
deviation signal.
www.indiandentalacademy.com
75. 2) Removal of functional appliance – when growth
is complete.
3) If removed when growth not complete – Proper
intercuspation.
www.indiandentalacademy.com
76. 4) Understanding of when, and for how long a
particular functional appliance should be worn.
First group – Full time
Second group – Part time
www.indiandentalacademy.com
77. 5) Proper functioning of LPM and RDP important for
growth
6) Sensory engram poorly developed in younger
children.
7) Utilization of high hormonal activity at puberty.
www.indiandentalacademy.com
78. Drawbacks
Lot of importance on condyle:
Fracture?
Peripheral comparator (occlusion)
discrepancies may be overcome by Dentoalveolar
changes.
www.indiandentalacademy.com
79. Occurrence of Class II end on relation is seen often?
Action of reverse pull headgear on maxilla
(primary cartilage)
www.indiandentalacademy.com
80. ESTIMATION OF CONDYLAR
GROWTH DIRECTION
( Stutzmann & Petrovic )
• Correlation between the growth direction
of the condyle and the sagittal
distribution of dividing cells in condylar
cartilage
www.indiandentalacademy.com
81. • Charlier et al 1968, 1969, Petrovic et al
1975: Distribution of dividing cells in
sagittal section of condylar cartilage of
juvenile rats
• Histologic and radiographic study
• Results: Treatment with both postural
hyperpropulsor and and growth hormone
STH produced increase in growth rate of
condylar cartilage as compared to controls
www.indiandentalacademy.com
82. Activator:
• Location of increase of dividing cells:
- more posterior in hyperpropulsor
- more anterior in STH
www.indiandentalacademy.com
84. • Supplement of dividing cells mainly
occurred in the posterior part of the
condylar cartilage
• Newly formed endochondral bone
trabeculae became oriented in a more
horizontal direction
• Posterior growth rotation of the condyle
www.indiandentalacademy.com
86. lengthening of preexisting endochondral bone
trabeculae under the condylar cartilage
growth of bone trabeculae that are formed in
parallel and posteriorly oriented to the
condylar cartilage
www.indiandentalacademy.com
88. Formation of Additional
Trabeculae
• Backward direction - the growth direction
of the condyle is more posterior
• Vice versa
www.indiandentalacademy.com
89. Variation in condylar cartilage
dividing cell number, mandibular
length, and trabecular-mandibular
plane angle
www.indiandentalacademy.com
90. • Administration of growth hormone and
treatment by functional appliance
• Administration of testosterone
• Resection of the lateral pterygoid muscle
• Seasonal Variations
www.indiandentalacademy.com
91. Growth rate increases
Angle has the tendency to close
Growth rate decreases
Angle has the tendency to open.
www.indiandentalacademy.com
92. CYBERNETIC MODEL OF THE
CONTROL MECHANISMS OF THE
CONDYLAR CARTILAGE GROWTH
RATE
www.indiandentalacademy.com
94. Effects of STH and Testosterone
Lengthening of the mandible is relatively
greater than lengthening of the maxilla
www.indiandentalacademy.com
95. Reduced stimulation of the RDP
Dividing cells are relocated in a less posterior
direction
Newly formed endochondral bone trabeculae
become vertically oriented
Closing of the angle
Anterior growth rotation.
www.indiandentalacademy.com
96. STH or testosterone level rises beyond a certain hormonal
level
"jumping of the bite"
in-creased contractile activity of the LP
stimulation of the retrodiscal pad
dividing cells are relocated in a more posterior direc-tion
opening of the angle
www.indiandentalacademy.com
posterior growth rotation
97. Effect of the Postural Hyperpropulsor
operation of con-frontation of the two dental arches
deviation signal
increased postural activity of the LPM
posterior rotation
www.indiandentalacademy.com
98. greater the alteration created
greater the supplementation of the condylar cartilage
growth rate and mandibular lengthening
greater opening of the angle
tends to decrease and may even become undetectable
opening of the angle appears only as a transient,
remedial occurrence
www.indiandentalacademy.com
99. Posterior growth rotation
Expression of a decreased growth level
increased activity of the LPM
Retrognathism
Posterior growth rotation
Less effective
Anterior growth rotation
More effective
www.indiandentalacademy.com
100. GROWTH ROTATION AND ALVEOLAR
BONE TURNOVER OF THE MANDIBLE
High alveolar bone formation rate
Anterior growth rotation
Low alveolar bone formation rate
Posterior growth rotation
Anterior rotation : high responsiveness of the
cells to growth-stimulating factors
www.indiandentalacademy.com
101. CONCLUSION
• Condylar growth direction presents spontaneous variations
as a function of the age of the animal and the time of year; it
can be modified by different experimental conditions
• Cybernetic model of the mechanisms controlling
mandibular growth based on research findings enables a
better understanding of the biologic phenomena involved in
mandibular growth rotation
• Measurement of this parameter in estimating condylar
cartilage growth direction may become a valuable element
in diagnosis and projection of treatment effectiveness in
dentofacial orthopedics
www.indiandentalacademy.com
103. Studies on functional appliances:
Activator:
• Petrovic and Stutzmann (1977), rat experiment
• Administration of growth hormone and treatment by
postural hyperpropulsor:
- increase in condylar cartilage growth rate
- hyperpropulsor: opening of Stutzmann angle
- growth hormone: closing of Stutzmann angle
www.indiandentalacademy.com
104. Studies on functional appliances:
Activator:
- lengthening of mandible measured from posterior
edge of condylar cartilage to mental foramen is
greater in case of opening of angle
• Administration of testosterone:
male rats for 3 weeks; stimulation in growth rate of
condylar cartilage and lengthening of mandible
(Stutzmann 1976, Petrovic, Stutzmann 1977, 1978)
www.indiandentalacademy.com
106. Studies on functional appliances:
Activator:
• Resection of lateral pterygoid muscle:
decrease in condylar growth rate and lengthening of
mandible
( Petrovic, Stutzmann 1972, 1974); opening of
Stutzmann angle
• Effect of postural hyperpropulsor:
greater the sagittal advancement, greater the condylar
cartilage growth rate and mandibular lengthening,
opening of angle; decreases with time
www.indiandentalacademy.com
107. Studies on functional appliances:
Activator:
• Growth rotation and alveolar bone turnover of
mandible:
high alveolar turnover rate with anterior
growth rotation than posterior rotation
www.indiandentalacademy.com
108. Studies on functional appliances:
• Woodside et al 1975:
- effect of activator treatment applied during the
evening and night on mandibular length
- periods of treatment were not coincident with
mandibular growth accelerations (except in 1 case)
- therefore, treatment with functional appliances
should be started coincident with naturally occurring
mandibular growth accelerations
www.indiandentalacademy.com
109. Studies on functional appliances:
• Altuna, Woodside 1977, 1985:
- primate experiments using juvenile and adult
animals in which mandible was opened 2, 4, 8, 12
mm. Without sagittal advancement
- openings greater than 2mm resulted in increased
mandibular length due to changes in condylar stress
www.indiandentalacademy.com
110. Studies on functional appliances:
• Woodside 1985: EMG activity in LPM by
Frankel functional regulator and activator
- both appliances generated similar amounts of
LPM activity after initial appliance insertion
www.indiandentalacademy.com
112. Studies on functional appliances:
• Woodside et al 1987: assessment of remodeling changes
in the glenoid fossa using juvenile monkeys
- Herbst appliance with progressive activations used
- extensive remodeling and anterior relocation of glenoid
fossa seen
• Voudoris 1988: same changes
• Angelopoulos 1991: changes in glenoid fossa remodeling
are stable
www.indiandentalacademy.com
113. Studies on functional appliances:
• Sessle et al 1990: longitudinal effect of functional
appliances on jaw muscle activity using 6 female
monkeys
- pre appliance and post appliance levels compared with
controls
- Herbst and functional protrusive appliances inserted
- decreased activity in superior and inferior head of LPM,
superficial masseter, anterior digastric; persisted for 6
weeks returning to previous levels after 6 week
observation period
www.indiandentalacademy.com
114. Studies on functional appliances:
• McNamara 1972, 1973: cephalometric,
electromyographic and histologic study of altered
functional position of lower jaw in monkeys
- increased activity of superficial head of masseter,
decreases activity of posterior part of temporal
muscle, increased activity of superior head of
LPM
www.indiandentalacademy.com
116. Studies on functional appliances:
• Elgoyhen, McNamara et al, 1972: advancement of
mandible of 6 juvenile monkeys for 5 months
- significant increase in rate of growth of condyle
- rate increased with increased time of appliance wear;
within 3 months with peak in 2 months; reduction in 4
months
www.indiandentalacademy.com
117. Studies on functional appliances:
• McNamara 1973, 1974: vertical dimension was increased
by using cast gold inlays opening bite from 2 to 15 mm in
incisor region in monkeys
- contraction of superior head of LPM
- elongation of elevator muscles
- gradual change
- inhibition of normal downward and forward growth of
maxilla
www.indiandentalacademy.com
118. Studies on functional appliances:
• McNamara, Hinton and Hoffman 1982
• Histologic analysis of temporomandibular joint
adaptation to protrusive function in young adult rhesus
monkeys (Macaca mulatta)
- twelve young adult female rhesus monkeys were fitted
with functional protrusive appliances for periods ranging
from 2 to 24 weeks.
www.indiandentalacademy.com
119. Studies on functional appliances:
- a proliferative chondrogenic response
accompanied by deposition of new bony
trabeculae at the bone-cartilage interface, though
greatly reduced in magnitude as compared to
juvenile monkeys
www.indiandentalacademy.com
120. Studies on functional appliances:
• DeVincenzo, Huffer, and Winn 1987
- A study in human subjects using a new device designed
to mimic the protrusive functional appliances used
previously in monkeys
- maxillary and mandibular posterior biteplates separated
by a sharp vertical interface perpendicular to the occlusal
plane
www.indiandentalacademy.com
121. Studies on functional appliances:
•
-The rate of mandibular length increase in the
treatment group over that of controls was
comparable to values reported in monkeys. Other
skeletal and dentoalveolar changes were likewise
similar to those found in monkeys.
www.indiandentalacademy.com
123. Studies on functional appliances:
Bionator:
• Mandibular response to orthodontic treatment with the
Bionator appliance - Mamandras and Allen AJO-DO
1990 Feb
- A group of 20 subjects who underwent successful
Bionator treatment was compared with 20 subjects who
were treated less successfully with the same appliance.
Both groups had similar advancements in their bite
registrations, as well as similar treatment times and
growth-prediction parameters
www.indiandentalacademy.com
124. Studies on functional appliances:
Bionator:
- both the total mandibular length and the horizontal
mandibular dimensions in the large-advancement group
was greater than that in the small-advancement group.
Only the vertical mandibular dimension remained
slightly, but not significantly, reduced when compared
with the small-advancement group
- more distal posttreatment condylar position in the largeadvancement group as compared with the smalladvancement group
www.indiandentalacademy.com
125. Studies on functional appliances:
Frankel appliance:
• Falck and Fränkel AJO-DO 1989 Oct
• Clinical relevance of step-by-step mandibular
advancement in the treatment of mandibular
retrusion using the Fränkel appliance
• 120 pts: 60 with end on relationship, 60 with step
wise advancement
www.indiandentalacademy.com
126. Studies on functional appliances:
Frankel appliance:
- better sagittal correction with gr. B
- opening of mandibular plane angle in gr. A
- more dentoalveolar changes with gr.A
- condyle in more anterior position in gr. A
- gr. A had better restraining effect on maxilla (point A
and maxillary molar)
www.indiandentalacademy.com
127. Studies on functional appliances:
• Arch width development in Class II patients
treated with Fränkel appliance - McDougall,
McNamara, and Dierkes AJO-DO 1982 Jul
• 60 treated with FR 1 and 2 and 47 untreated cases
• changes in lingual, buccal, and alveolar arch
widths were compared.
www.indiandentalacademy.com
128. Studies on functional appliances:
• expansion of the maxillary and mandibular dental
arches and their supporting structure occurs
routinely with a functional regulator (FR-1 or FR2)
• largest expansion in the premolar and molar
regions, lesser in the canine region; in the maxilla
narrower arches tend to expand more than wider
arches
www.indiandentalacademy.com
129. Studies on functional appliances:
• Comparison of Herbst and Frankel appliances McNamara, Howe, and Dischinger AJO-DO 1990 Aug
• A comparison of the Herbst and Fränkel appliances in the
treatment of Class II malocclusion
- 45 pts with acrylic splint Herbst and 41 pts with FR2
- cephs compared with 21 untreated class II pts
www.indiandentalacademy.com
130. Studies on functional appliances:
- Significant skeletal changes were noted in both
treatment groups, with both groups showing an increase
in mandibular length and in lower facial height, as
compared with controls.
- Greater dentoalveolar treatment effects were noted in
the group wearing the tooth-borne functional appliance
than in those wearing the tissue-borne appliance.
www.indiandentalacademy.com
131. References
Dentofacial Orthopedics with Functional
Appliances
Graber, Rakosi, Petrovic
Treatment objectives and case retention:
Cybernetic and myometric considerations
R.M. Jacobs Am J Orthod, 58:552-564, 1970
Removable orthodontic appliances
www.indiandentalacademy.com
Graber and Neumann