Functional appliance /certified fixed orthodontic courses by Indian dental academy

Functional Jaw Orthopedics
- Criteria for Case Selection

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INDIAN DENTAL ACADEMY
Leader in continuing dental education


Index
I) FUNCTIONAL ANALYSIS
1.
2.
3.

DETERMINATION OF NATURAL HEAD POSITION
TMJ EXAMINATION
ASSESSMENT OF FUNCTIONAL STATUS OF LIPS, CHEEKS
AND TONGUE
DYSFUNCTIONS OF THE TONGUE
ASSESSMENT OF RESPIRATION
PATTERN OF DEGLUTITION.

4.
5.

CEPHALOMETRIC EVALUATION
–
–
–
–
–

CEPHALOMETRIC ANALYSIS FOR FUNTIONAL
APPLIANCE
PITCHFORK ANALYSIS
CEPHALOMETRIC ANALYSIS FOR EVALUATING A-P
DISCREPANCY OF THE JAW BASES
CEPHALOMETRIC TONGUE ANALYSIS
VISUALIZED TREATMENT OBJECTIVE

SKELETAL MATURITY INDICATORS FOR
TIMING THE FUNCTIONAL
APPLIANCE THERAPY
•
•
•
•
•

CERVICAL VERTEBRAL MATURITY
INDICATOR
HAND WRIST RADIOGRAPHS
DENTAL CALCIFICATION
FRONTAL SINUS
SOMATIC MATURATION – STANDING
HEIGHT AND PEAK GROWTH
VELOCITY

Introduction
• Wolff (1893) on form and function
• Benninghof’s study of stress trajectories
in the midface
- Demonstrate the response of bone to
functional forces.
- Petrovic - The adaptability of the condyle
to various topographic and functional
relationships during the growth period

Functional analysis
• If function is abnormal,
• whether it should be altered
• whether the change in forces produced
can be used to help solve orthodontic
problems.
• If one function is changed, will it affect the
other functions, which may then exert
different forces on the dentofacial
skeleton.

DIAGNOSTIC EXERCISES
1. Determination of the postural rest position of
the mandible and interposed freeway space or
interocclusal clearance
2. Examination of temporomandibular joint (TMJ)
function or dysfunction and condylar movement
in performing the stomatognathic system’s
tasks
3. Assessment of the functional status of the lips,
cheeks, and tongue, with particular attention to
the roles they play in dentofacial abnormalities

• In the postural rest position, synergistic and
antagonistic muscular components are in
dynamic equilibrium; their balance is maintained
with basic muscle tonus.
• The rest position is the result of a myostatic
antistretch reflex that responds only to the
permanent exogenous force affecting the
orofacial system (i.e., gravity). As a
consequence the rest position depends on and
alters with the position of the head. Thus natural
head position (NHP) must be determined for
each patient.
• Cephalograms should be taken in NHP.

The movement of the mandible from postural rest to
habitual occlusion is of special interest for all functional
analyses. It consists of two components:
• hinge (rotary) action and
• translatory (sliding) movement.
The objective of examination is to assess not only the
magnitude and direction of these movements but also
the extent of action of each hinge or sliding component.
During the closing maneuver from rest position, two phases
of movement can be observed
• the free phase from postural rest to the point of initial or
premature contact and
• the articular phase from initial contact to the centric or
habitual occlusal position.

• Functional patterns without articular phases that
produce free movement from rest to full occlusal
contact are seen in only a few completely
balanced occlusions. A slight sliding component
(as much as 2 mm), particularly in the
transitional dentition, is a normal phenomenon.
• If the pattern is abnormal, the sliding may be
caused by neuromuscular abnormalities,
disturbances in dental interrelationships, or
compensation of skeletal discrepancies.


Assessment of the postural rest
position.

• Influenced by gravity
• Patient seated upright (back
unsupported.)
• The head is oriented with the patient
looking straight ahead at eye level.
• Looking directly into a mirror helps
establish optimal head posture

Command methods – wet the lips and
swallow
Phonetic exercises – “m” & “c” or Mississippi
Noncommand methods – talk unrelated
subjects & observe carefully.
Combined methods –swallow & relax
Clinician gently palpates the submental
muscles to assess tonicity

Registration of the postural rest position
• Direct intraoral method – Plaster core
registeration but not feasible for children in the
mixed dentition
• Direct extraoral method – difference between
distance from soft tissue nasion to menton in
both postural rest and habitual occlusion. But
soft tissue can mislead.
• Indirect extraoral method - Reontgenography,
cephalometry, electromyography,
cinefluorography, and kinesiography

Cephalometric registration
Three lateral ceph are taken
• first in postural test,
• second in initial contact, and
• third in full habitual occlusion.
Two measurements can be taken on each film.
One records hinge movement of the condyle in the
vertical plane.
The second assesses sliding or translatory action in the
sagittal plane.
Comparison of the single movements permits an
assessment of the path of closure of the mandible, which
must be determined from rest to initial contact and initial
contact to full occlusion.

If a significant sliding component is observed from initial

Class II treatment
• Posterior displacement combined with
projected horizontal growth directions, the
prognosis is very good.
• If anterior displacement and a vertical growth
vector are present, the prognosis is quite poor.
• Anterior displacement +horizontal growth
• Posterior displacement + vertical growth.
- the prognosis is not good
• It can be improved or worsened depending on
the age of the patient and the specifics of the
facial pattern.

Class III malocclusions.
• Hinge-type condylar function is often associated with
Class III malocclusions with straight paths of closure.
• successful functional appliance treatment possible only if
the magnitude of the sagittal dysplasia is moderate and
therapy is begun in the early mixed dentition.
• If the path of closure is up and back (an anterior postural
rest position), the prognosis is even poorer.
• Anterior displacement that creates an up and
forward path of closure with combined rotary and
translatory action of the condyle from postural rest
to habitual occlusion, the prognosis is much better
and treatment success is possible, even. in the
permanent dentition.

Pseudo-forced bite
•

Functional therapy is the most efficient mode of treatment in the
mixed dentition. But functional analysis alone is insufficient to
determine prognosis because not all Class III has anterior paths of
closure with good prognosis.

•

Sometimes a skeletal Class III relationship is partially compensated
by labial tipping of the maxillary incisors and lingual tipping of the
mandibular incisors.

•

(Diagnosis is usually possible only with the aid of cephalometric analysis).

•

Because of the extreme tipping possible, an anterior sliding
movement into occlusion can occur

•

Uprighting the incisors into proper axial inclinations results in a
severe Class III sagittal tooth relationship.

•

Orthodontic treatment is difficult as the incisors are already
overcompensated before treatment.

•

Orthognathic surgery www.indiandentalacademy.com

Path of closure - Vertical plane
True deep bite
Pseudo deep bite
Infraocclusion of the
posterior segments.

Normal eruption of the
posterior teeth

Lateral tongue posture or Over- eruption of the
tongue thrust habit
incisors.
Large interocclusal gap
Cl II div 2 with adequate
lip line

Small freeway space
Gummy smile & poor lip
line

Elimination of
environmental factors
inhibiting eruption of the
posterior teeth.

Intruding incisors
Distalize maxillary
molars to control the
vertical dimension


Fnl appl is beneficial

Not of much use

Path of closure - transverse plane
•

It consists of observing the behavior of the mandibular midline as the teeth
are brought together from rest position to habitual occlusion.

• Two functional types of crossbite.
Laterocclusion - Midline shift occurs only in full occlusion but coincident in rest
position.
• The prognosis for functional appliance therapy is good.
• Treatment requires eliminating the disturbance in the intercuspation. This
often is done by widening the narrowed maxillary arch, thus improving
function. The procedure also can be done in the permanent dentition
• Some evidence suggest that prolonged crossbite relationships can lead to
asymmetric jaw growth if allowed to continue for a number of years during
the growing period - (Egermark-Ericson, Thilander).
Laterognathy - Persistence of the midline shift in rest position and in occlusion.
(e.g., a true asymmetric facial skeleton).
• The prognosis for treatment is poor.
• Successful functional appliance treatment is not possible in such cases; in
severe cases, surgery is the only alternative.

Why should the TMJ be examined?
• To identify the incipient symptoms of TMD
1. Early elimination of functional disturbances can prevent
incipient TMJ problem. This is an indication for early
orthodontic treatment.
2. If the temporomandibular structures are abnormal at the
start and hypersensitivity is a problem, the possibility of
exacerbating the symptoms exists
Fortunately, this seldom happens; functional appliances
often eliminate unfavorable sensory reactions in the
process of posturing the mandible forward. This is an
important requisite for the treatment of many adult TMJ
eases.
If TMJ problems are present in the deciduous dentition,
forward posturing may be better achieved in a staged
progression.

Early symptoms of TMJ problems
• Clicking and crepitus

• Sensitivity in the condylar region and masticatory
muscles – supr head of LPM
• Functional disturbances
1. hypermobility
2. limitation of movement
3. Deviation
• Radiographic evidence of morphologic and
positional abnormalities

Clicking & Crepitation
• Initial – Retruded condyle in relation to
disc
• Intermediate – uneveness of the condylar
and disc surfaces
• Terminal – condyle moving too far
anteriorly on opening
• Reciprocal – incoordination between the
displacement of condyle and disc both on
opening and closing.

Tenderness
• Tenderness to palpation condylar region in only
5.3% of the case
• The most important & initial sign is tenderness of
the temporalis, masseter & lateral pterygoid
muscle (LPM) (though its difficult and relatively
unreliable) supr head is of particular importance.


Functional disturbance
• 50% Hypermobility - an opening of more than 45 mm in 6 to
8-yrs, more than 49 mm in 10 to 12-yrs - mostly habitual,
but it can indicate a predisposition to later
temporomandibular dysfunction (TMD).
• In 22% an anterior displacement of the condyle over the
articular tubercle occurred.
• Limited movement because of muscle spasm -not a major
concern.
• Deviation of the opening or closing movement sagittally or
transversely (24%).
• In 11.5% an S opening occurred as the condyles moved
forward or backward unevenly in the functional maneuvers.
• Deviation was most frequently accompanied by crepitus or
clicking and Condylar dislocation.
• Neuromuscular involvement in TMJ problems was also
observed in the lip and tongue areas.

Auscultation
• stethoscope is used to check for signs of clicking and
crepitus.
• A stereostethoseope helps to determine the magnitude
and timing of abnormal sounds for each joint
simultaneously.
• If crepitus is noted, the patient is instructed to bite
forward into incision and then repeat the opening and
closing movements. These movements are checked for
any sounds with the stethoscope. Most often, sounds
disappear in the protruded position.


Palpation
•
•

The condyle and fossa are palpated.
The posterior surface can be palpated by inserting the little finger in
the external auditory meatus and checked for tenderness,
synchrony of action, and coordination of relative position in the
fossae.

•

Palpation of muscles of mastication and muscles of facial
expression should be carried out. Lateral pterygoid can be
palapated by by placing the forefinger behind the maxiilary
tuberosity, right above the occlusal plane, with the palmar surface of
the finger directed medially toward the pterygoid hamulus.


Functional analysis
• . Dislocation of the condyles and discoordination
of movements are early symptoms of functional
disturbance.
• Gnathologic registration may be useful.
• Myographic recordings also assist in this
functional analysis. Simple electronic devices
help measure the silent period of muscular
contraction—a cardinal sign of dysfunction in
many cases.


•
•
•

•

Functional movements of the mandible and condyles are carefully
assessed.
Maximum opening is measured between the upper and lower
incisors with a Boley gauge. In overbite cases this amount must be
added and in open bite the distance must be subtracted.
The direction of opening and closing movements should be
registered graphically with curves. Premature contacts and
deviations in sagittal and transverse directions are assessed.
Perioral neuromuscular abnormalities, crepitus, and tenderness of
the LPM are important signs of early TMJ dysfunction. As a rule of
thumb the diagnosis çf incipient TMD can be made if two of these
three signs are present.


Prevention of functinal TMDs
•
•
•

Early care of deciduous teeth (especially the
molars) for caries and interference.
Elimination of tooth guidance crossbites and
unwanted translatory condylar movement in
the deciduous dentition
Elimination of neuromuscular dysfunctions
(especially those involving the lips) and habits
that force the mouth open


Indications of early orhtodontic
treatment
•
1. Class II malocclusions with excessive overjet,
horizontal growth pattern, and lower lip cushioning to the
lingual of the upper incisors (lip trap)
2. Deep overbite problems
3. Anterior open bite with associated abnormal llp,
tongue, and finger habits
4. Crossbite conditions
• In patients exhibiting clicking and functional
disturbances, muscle exercises and interceptive
appliance guidance (e.g., bite planes, the bionator) are
recommended.

Deglutition
• In neonates the tongue is relatively large and located in
the forward suckling position for nursing. The tip inserts
through the anterior gum pads and assists in the anterior
lip seal. This tongue position and coincident swallowing
are termed infantile or visceral.
With eruption of the incisors at about 6 months, the
tongue position starts to retract. Over a period of 12 to
18 months, as proprioception causes tongue postural
and functional changes, a transitional period ensues.
Between 2 and 4 years the functionally balanced, or
mature, somatic swallow is seen in normal
developmental patterns.
•

Symptoms of a retained visceral swallowing
• Forward tongue posture
• Tongue thrusting during
swallowing,
• Contraction of the perioral
muscles (hyperactive
mentalis and orbicularis
oris contraction),
• Excessive buccinator
hyperactivity, and
• Swallowing without the
momentary tooth contact
normally required.

• Normal deglutition.
• No tongue thrust or
constant forward posture
occurs.
• The tip of the tongue is
supported on the lingual
of the dentoalveolar area;
• The contraction of
perioral muscles is slight
during deglutition, and the
teeth are in momentary
contact during the
swallowing cycle.


Complex tongue thrusting problem
•
•

Open-bite conditions often exist in both anterior and posterior
regions.
Elimination of the problem is usually more difficult in a complex
tongue thrust, and a long period of retention is necessary to prevent
the return of the visceral swallowing pattern

Simple tongue posturing:
More amenable to interception
• localized anterior tongue posturing forward during rest and active
function with localized anterior open bite.
• Attendant muscle abnormalities are more adaptive than primary
• Prognosis for functional therapy is usually good, and autonomous
improvement can often be seen.


Treatment options
• Myofunctional therapy
• Lip exercise
• Because of the diversity of tongue function
during swallowing, tongue exercises are not
recommended before or during treatment.
During active treatment, tongue posture and
function are controlled by the appliance
• If spaces are present, the tongue tends to find
them and press into them; hence anterior space
closure is advisable.

Examinatin of Tongue
• Tongue function, posture, size, and shape
are significant.
• Factors altering tongue posture:
• Class III - Low lying anteriorly postured
tongue
• Nonphysiologic design of nipple of baby
bottles
• Nasal and pharyngeal blockade like
excessive epipharyngeal lymphoid tissue

Tongue function
•
•

Primary – retained infantile swallow
Functional appliance therapy indicated
Secondary - basal skeletal dysplasia
Functional appliance therapy not
indicated


Tongue posture
•

the basal tongue posture at rest position is assessedat three
regions—root, dorsum, and tip.
• The root is usually flat in cases of mouth breathing and deep overbite
caused by a small tongue; in all other cases, slight contact of the
tongue usually occurs with the soft palate.
• In Class II. division 1 malocclusions and deep overbite the dorsum of
the tongue is arched and high; in all other malocclusions a tendency
exists for the tongue to flatten in accordance with the length of the
interocclusal space.
• The tip of the tongue is usually retracted in Class II. division 1
malocclusions, but in other malocclusion categories a sbght anterior
gllding of the tongue tip occurs as the mandible moves into postural
rest position.


Tongue size
• Macroglossia
– fills the oral cavity
- narrow epiglottis
- peripheral indentations on the tongue
- procumbent incisors
- protruded tongue
- open bite
 Etiology
 Hypothyroidism
 Hyperpituitarism
 Down syndrome

Microglossia
:
1.
2.
3.

The protruded tongue tip reaches the lower incisors at best
Floor of the mouth is elevated and visible on each side of the diminutive
tongue.
The dental arch reflects the small tongue size and is collapsed and
reduced, with extreme crowding in the premolar area.

4.

A severe Class II relationship is usually evident.

5.

Third molars are usually impacted at the angle of the jaw.

6.

severe functional disturbances also present due to the lack of centrifugal
force of the tongue.

7.

The localized effects are extreme. In some cases, teeth from the
posterior segments are tipped so markedly to the lingual that they touch
each other in the midline. the effects limited mostly to the dentoalveolar
area.

• In the case of hypoglossia the functional
abnormality primarily affects the dentoalveolar
region, not the basal skeletal structure. Oral and
vestibular screens incorporated into functional
appliances have similar capabilities. Fixed
appliances also have primarily localized effects,
which is the reason locating the malocclusion
and correcting the sagittal dysplasia are so
important before applying even simple inhibitory
therapy.


Tongue dysfunction
• The most common tongue dysfunctions involve selective
outer pressure (pressing) and tongue biting. Tongue
thrusting can be anterior, posterior, or combined. The
consequences of the localization of aberrant pressures
depend on the area of applied pressure:
1. Anterior open bite results from anterior tongue thrust
and posture.
2. Lateral open bite and deep overbite result from lateral
tongue thrust or postural spread that causes infraocclusion of the posterior teeth.
3. Edge-to-edge incisal and cuspal relationships.
•


• Open bite: Dentoalveolar anterior and posterior
open-bite problems are usually attributable to
abnormal tongue posture and function and
usually respond successfully to functional
appliance intervention in the mixed dentition.
• Deep bite: This also is true for eases of deep
overbite in which lateral tongue spread during
function and posture leads to infraclusion of the
posterior teeth. The space is maintained by
invagination of the peripheral portions of the
tongue into the interocclusal space while the
mandible is in the postural rest position. In such
cases, a large freeway space is evident, and the
deep overbite is functional.

Functional pseudo- overbite
•
•
•
•

Caused by supraclusion of the incisors
small freeway space is apparent.
Functional appliance is indicated in the absence of developmental

disturbances
Fixed appliances and orthopedic guidance serve better. Surgery is the
ultimate treatment.

Skeletal open bite:





Genetically determined vertical growth pattern
marked antegonial notching.
Prognosis for orthodontic therapy is unfavourable.
Bimaxillary protrusion: occurs when tongue thrusting is seen in horizontal
growers. Simulataneous spacing in both upper and lower incisors is evident.



In a vertical growth pattern th tongue thrust can open the bite, and the lower
incisors may be tipped lingually.


Examination of the lips
1. If only a slight contact or a very small gap is evident between the
upper and lower lips, the lips are competent.
2. If a wide gap is present with the lips – incompetent lips
3. If the lips seem normally developed but the upper incisors are
labially tipped, making closure difficult – potential lip incompetency.
The lower lip trap then enhances the already excessive overjet,
makes the upper incisors mobile & retrocline and crowd the lower
incisors. Early treatment of these problems is an important
preventive measure.
4. If the lower lip is hypertrophic, everted, and redundant (i.e., with an
excess of tissue), little can be done to improve the situation by
orthodontic therapy.


Dysfunction of the lips
•

The most common is sucking or biting of the lower lip, known as
mentalis habit. In this type of dysfunction, contact usually occurs
between the tongue and lower lip and can be observed during
swallowing. Consequences of the combined muscle abnormality
include the opening of the bite anteriorly and the lingual tipping of
the lower incisors with crowding and labial malpositioning of the
upper incisors. Retraction or dehiscence of the labial gingival tissue
overlying the lower incisors can occur.

•

Upper-lip biting is a habit frequently seen in schoolchildren. It is a
stress-strain relief syndrome. Tongue function can be normal, with
the hyperkinetic behavioral activity and abnormal lip habit as the
main pathologic factors. Class II malocclusion can provide the
overjet that requires lip compensation, which in turn exacerbates the
original overjet.


•

Primary lip dysfunction - overjet with labial tipping of the upper and
lingual tipping of the lower incisors is evident, and only a slight
skeletal sagittal discrepancy occurs. The lip habit enhances the
original slight-to-moderate overjet.

•

Secondary lip dysfunction - the original overjet is caused by a
significant sagittal discrepancy, usually with mandibular
underdevelopment. The inclination of the incisors can be normal.
The lower lip cushions the gap between the upper and lower
incisors, primarily as an adaptation to the morphologic malrelations.
Lip activity may not be as intensive but may rather be more adaptive

Functional therapy is successful only in cases of primary
dysfunction. In the case of secondary dysfunction, functional
therapy is inferior to other orthopedic, orthodontic, or surgical
methods.

Respiration
Mouth breathing:
• In 1968, Ricketts described the “respiratory obstruction syndrome,” visceral- type swallowing, predisposition to open bite, unilateral or bilateral
crossbite and slight upward deflection of the head.
•

disturbed nasal respiration predisposes to ClI div 1 malocclusion;
narrowness of the upper arch; crowding of the upper and lower arches; and
vertical growth patterns.

•

If the tonsils and adenoids are enlarged, with a compensatory anterior
tongue posture, the patient cannot tolerate a bulky acrylic appliance in the
oral cavity.

•

Appliances indicated in mouth breathers - Clark twin block, Hamilton
expansion activator

•

Lip seal is usually inadequate, tongue is a low posture and disturbed
function. If this condition persists after treatment, relapse will occur.
Orthodontic therapy should aim at establishing normal nasal respiration.
Unfortunately in some patients with allergies or deviated nasal septums, this
is not possible during the growth period.

•

Water hold test can be performed.

•

The presence and size of the adenoids and tonsils also can be
estimated on lateral head films. An arbitrary scale of small, medium,
or large can be used in both the clinical examination and the lateral
cephalogram.

•

Spontaneous regression of epipharyngeal lymphoid tissue occurs
with development. At 10 years of age, 180% of the lymphoid tissue
is present that will still be present at 18 years of age. Obstructive
adenoids usually regress without surgical intervention.

•

Nasal respiratory resistance also can be measured using an indirect
polysomnographic approach.

•

In habitual mouth breathing, respiratory resistance is low, whereas
in structurally conditioned mouth breathing, it is high. The diagnosis
of mouth breathing is probably best made by the otolaryngologist.


Functional therapy in respiratory problems
1. In habitual mouth breathing with small respiratory
resistance, functional therapy is indicated. Exercises can
be prescribed. Holding a sheet of cardboard between the
lips is one satisfactory means of enhancing lip seal.
2. If structural problems occur with excessive adenoid
tissue and allergies, ENT consultation and possible
treatment should be sought. If it is successful,
orthodontic treatment can then begin.
3. If the structural conditions are unalterable, functional
appliance therapy cannot be instituted. In such cases,
only active fixed-appliance mechanotherapy is likely to
produce the changes desired. Even then, the stability of
the results is questionable unless autonomous
improvement occurs.

Significance of Functional Analysis in Treatment
Planning with Removable Appliances

Class II malocclusion:
•
•
•
•

Anterior postural rest position of the mandible
Large freeway space,
Mandibular overclosure, and deep bite
Early TMD symptoms with deep overbite, horizontal
growth pattern, and abnormal perioral muscle function.

• Respiratory disturbances potentially interfering with
normal growth and developmental pattern should be
eliminated (if possible) before orthodontic treatment.


Class III malocclusion:
• Prognosis is favorable in mild to moderate skeletal class
III (true forced bite) intervened at an early stage.
• Unfavorable when pseudo forced bite characterized by
partial dentoalveolar compensation with anterior sliding
on closure.
Open bite malocclusion:
• . In primary dysfunctions with abnormal muscle action as
a major etiologic factor, the growth pattern is usually
average or horizontal.
• If the growth pattern is mostly vertical, the dysfunction
may be more secondary or adaptive.
• Functional appliances are likely to be successful in cases
with primary dysfunction and at least an average growth
pattern.

Cephalometric for functional
appliance therapy


Analysis for facial skeleton
1.Saddle angle (N-S-Ar)
• Normal 123±5º
• Less than 118º -Antr post gl.fossa- favorable
• Greater than 128º-postr post gl.fossa -favorable
Look for –
1.Articular angle - less than 143±6º- favorable
2.Ramal length- Long - favorable
Uncompensated:
Greater saddle angle + greater articular angle +
Lesser ramal angle-unfavorable

2.Articular angleS-Ar-Go angle Upper and lower parts of the posterior
contours of facial skeleton
• Large art in retrognathic mandible
• Small art angle in prognathic mandible
• Can be altered by orthopedic and orthodontics
• Reduction in the Ar angle
1.Anterior repositioning of Md
2.Closing the bite
3.Mesial migtratin of molars
Between 9-15 years:
Decreases by 2.5* for vertical growers and
2.9* in horizontal growth

3.Gonial angle
• Shows –
1. Form of the md.
2. Direction of mandibular growth - where functional
appliance indicated.
• Small lower gonial angle -horizontal grower – favorable
• Large lower gonial angle-vertical grower - unfavorable if
growth is considered during appliance fabrication, then
it can be used as initial therapy but finally – surgery
9yr – gonial angle 125.5º
Lr gonial angle - 69.5º- hor
133.4º
78.3º-ver
• Decreases 2.89º-horizontal growth
2.42º-vertical growth

4. Jarabak ratio:
Postr face ht×100 = 62 to 66%
Antr facial ht
9yrs
H
• Post facial ht. 69.5
• Antr facial ht. 103
•
•

V
64.1
106.6

9-15yrs
H
11.05
12.18

Hor 67.5%-69.9%
Ver 60.1%-62.7%


V
10.8
12.71

5. Antr cranial base length (Se-N)
• Horizontal growth 68.8mm at 9 yrs and increases by
4.46mm between 9- 15 yrs
• Vertical growth 63.8mm and increases 3.52mm
between 9- 15 yrs.
Therefore greater antr cranial base length in horizontal &
lesser in vertical growth
6.Postr cranial base length (S-Ar)
• Depends on posterior face ht and position of gl.fossa
• Short postr cranial base is seen in
1. Vertical growers
2. Skeletal open bite
•
•

Hor – 32.2mm
Ver -30mm

9.16mm (in 6yrs) 9-15 yrs
4.47mm

Analysis of jaw bases
1.SNA- Sagittal relation of the antr limit of the maxillary apical base
Average 82.2 ± 2º - if larger than 84º functional appliance is
contradicted
SNA doesnt change significantly with functional appliance
9yrs
79.5
79.73
79.0

15yrs
81.28
81.57
80.57

•
•
•

Avg
Hor
Ver

•
•

Functional appliance can decrease SNA to a moderate extent.
A significant decrease is possible by H activator(7-8mm sagittal & 23mm vertical) or a twin block

2.SNB- Smaller indicative of retrognathic mandible
- Functional appliance is indicated
• Hor- 77.2º-80.5º (3.2º)
• Ver- 74.3º-75.9º (1.6º)
Therefore growth directions and greater
increments make the success of the functional
therapy.
3.Basal Plane Angle (pal-mp)
• Hor – small 23.4º-20.5º (-3º)
• Ver – larger 32.9º – 30.9º (-2º)

4.Inclination angle 85º(PP-Pn)Anteinclination is seen in horizontal growers
and mouthbreathers
Retroclined palatal plane is present in
compensated ver growers
Doesnt correlate with growth pattern or
facial type
But maxillary base inclination changes with
fnl appl therapy
• Therefore mid treatment evaluation is
indicated periodically

5. Rotation of the jaw bases:
A) Intermatrix rotation
B) Matrix rotation = total rotation is what we see cephalometrically.
•
•
•

Remodelling of mandible at the gonial and symphyseal area
Horizontal – apposition at gonial, resorption at symphysis.
Vertical – apposition at the gonial, and resorption at genium.

•
•

Matrix rotation – neurovascular envelope
Functional appliance and growth can influence the mandibular
rotation
Maxillary base is not altered by growth, but environmental factors
like neuromuscular dysfunction, occlusal forces, gravity and
nasorespiratory malfunction.

•


6. Mutual rotation of jaw bases:
Horizontal rotation – deep bite – convergent rotation
Vertical rotation – open bite – divergent rotation
Cranial rotation of both bases – offset deep bite
Caudal rotation both bases – offset open bite
Therapeutic control of vertical dimension is not
possible and therefore compensatory treatment is
indicated.


7. Linear measurement of the jaw bases:
•
•

The length of mandibular and maxillary bases and ascending ramus is
measured relative to Se – N.
Ideal dimensions can be calculated using the ratios:
N-Se:Md base
20:21
Asecending ramus:Md base
5:7
Max base: Md base
2:3

Mandibular base:
The mandibular base should be 3 mm longer than Se-N until 12th year
and 3.5 mm longer after 12th year. A length 5mm less than this average is
considered normal until 7 years and length 5mm or more is considered normal
until 15 years.
9 yrs
15 yrs
Horizontal pattern

67.59 mm

77.35 mm

Vertical pattern

65.23 mm

73.5mm


Extent of maxillary base:
• It is the distance between PNS and Pt A projected perpendicular to palatal
plane.
• Growth potential of mandible is greater than that of maxilla hence SNB angle
increases and ANB decreases.
9 years

15 years

Horizontal patterns

44.56 mm

48.6 mm

Vertical patterns

44.0 mm

47.16 mm

Length of ascending ramus:
• Measured from gonion to condylion. Condylion is constructed by the
intersection of FH plane on the tangent to the ramus.
• Ideal FH plane is also constructed “distance between soft tissue nasion and
palatal plane is bisected along the Pn line. From this point a straight H line is
drawn paralel to Se-N plane.”
• Ramal length determines the posterior facial height.
• It is longer in horizontal growers with 48.9mm at 9 years increasing to 68.6
7mm at 15 years.
• It is shorter in vertical growers 44.47 mm at 9years 51.7 mm at 15 years.

Evaluation of the length of the jaw
bases
1.
•

Mandibular base:
Md base = N-Se + 3mm indicates an age related
normal mandibular length and an average growth
increment.
•
If the base is shorter the growth increment is larger, if
the base is longer the growth increment is shorter.
•
Retrognathic mandible may have short or longer base.
Short base – retrognathism is due to growth deficiency
Long base
1) functional retruded position because of overclosure
or occlusal guidance
2) the mandible is morphologically built into the facial
skeleton in a posterior position.

2. Maxillary base:
It is related to N-Se and to the Md base. Deviation from the Md
base indicates that the Mx base is too short or too long.
3. Ascending ramus:
If the ramus is too short, a large amount of growth can be
expected because the growth pattern is not vertical.
4. Morphology of the mandible:
• Orthognathic type – width of ramus is equal to ht of body of
mandible including ht of alveolar process and incisor. The condyle
and coronoid are almost on same plane.
• Retrognathic – the ramus is narrow and short, the symphysis narrow
and long. The coronoid process is shorter than condyle and the
gonial angle is acute or small.
• Prognathic – ramus is wide and long, symphysis is wider in saggital
plane, the gonial angle is acute or small.

Analysis of dentoalveolar
relationship
Axial inclination of the incisors:
1. Upper incisors:
Upper incisor to SN angle:
a. 94 -100* until 7th year
b. 102* in the permanent dentition
c. larger angle indicates incisor procumbancy
2. Lower incisors:
Incisor to mandibular plane angle:
90* - average
smaller angle – lingual tipping of incisors – advantageous for
functional appliance treatment. Activators are more effective in the
saggital plane and tend to tip the lower incisors labially.
if lower incisors are already labially tipped anterior repositioning of
mandible and uprighting of incisors is necessary.


3. Positioning of the incisors:
Maxillary incisor to N-Pog line: 2 to 4mm
Mandibular incisor to N-Pog line:

-2 to +2 mm

Proclined incisors are tipped, if the axial inclination is
correct, then bodily movement is required.
Mandibular incisors behind this line can be moved
labially because space is available and anterior to this
line should be moved lingually.


Cephalometric evaluation of treatment progress in
mixed dentition


Cephalometric evaluation of A-P
discrepancies


• Steiner’s anaylsis:
• An ANB angle of 2 ± 2° was considered
Class I.
• Angles greater than 4° were considered
Class II.
• Angles less than 0° were considered
Class III.

• Wits appraisal in Class I patients with 0 ± 2
mm.
• greater than 2 mm indicated a Class II skeletal
relation, and
• measurements less than – 2 mm indicated a
Class III skeletal relation.
• The Wits analysis is a function of the inclination
of the occlusal plane
• So standardization was attempted on the basis
of an inclination of the occlusal plane of 8° to the
palatal plane (NL). (AJO-85, Williams)

McNamara analysis:
• The relationship of either A or Pog to nasion
perpendicular of 0 ± 2 mm was considered Class
I.
• For differences greater than 4 mm between
points A and Pog,
• If A is anterior to Pog, it is considered Class II.
• If Pog is anterior to A, it is considered Class III.


Cephalometric assessment of sagittal relationship using
palatal plane - 1994 Apr AJO - Ram Nanda and Merrill
• the first part evaluated changes in the inclination of
palatal plane and in the linear distances from the age of
6 to 24 years and indicated the inclination of the palatal
plane was stable throughout the growth period studied.
• The second part established acceptable adult norms by
evaluating in non-orthodontically treated with good facial
balance.
• The third part evaluated the proposed measures in
pretreatment radiographs in malocclusions to compare
the results of various diagnostic criteria for assessment
of sagittal jaw relationships.
• The distance between projections from points A and B
on the palatal plane (App-Bpp) was found to be the best
indicator of sagittal jaw relationship when compared with
the angle ANB, the Wits appraisal and N perpendicular,

Changes in palatal plane inclination
• The growth changes in the inclination of the
palatal plane were measured relative to the
pterygomaxillary vertical plane
• on an average Pp decreased by 0.16° in the
female subjects and increased 2.22° in male
subjects from age 6 to 24 years.
• The correction factor iwas found to be less than
0.01 mm, which was considered insignificant.
• This confirmed the observations that the palatal
plane remains relatively stable throughout
growth.
• This stability over time validates use of the
palatal plane as a reference plane for
measurement.

Changes during growth
• Mean changes in the measurements App-Bpp, AppPogpp, Mpp-Dpp, and Mpp-Pogpp from age 6 to 24
years showed that those persons who are at the
extremes at age 6 years may remain at or near the
extremes. In some cases they move closer to from the
average than they were at age 6 years.
• The measures using point Pogpp were more negative
than the measurements based on points B and D, and
the range was larger. The range for App-Pogpp was
13.66 mm for the women and 24.66 mm for the men. For
Mpp-Pogpp the range was 13.94 mm for the women and
24.87 mm for the men.


The advantages of using palatal plane are
(1) growth changes of point N do not influence the result
(2) rotation of the jaws does not influence the result
(3) inclination of the occlusal plane by dental effects is
excluded
(4) vertical effects of points A and B are decreased in
comparison to other methods of analysis.
(5)Palatal plane is to be preferred over the FOP
because the occlusal plane changes its inclination
during growth and with orthodontic treatment.

(6)Palatal plane is desirable since this skeletal plane is in
close proximity to the areas under consideration.
(7)The proximity of palatal plane to the dentitions and their
apical bases in both the maxilla and the mandible
allowed an evaluation of the maxillomandibular complex
by relating the mandible to the maxillary plane and not
by how the maxilla and the mandible related to nasion,
cranial base, functional occlusal plane, or any other
distant reference point.
(8)Palatal plane was also selected because it is stable
throughout life.
• The palatal plane appeared to maintain a parallel
relation over the growth range Broadbent.
• The palatal plane maintained a constant angular
relationship with the anterior cranial base –(Brodie,
Bjork) and to the pterygomaxillary vertical plane (Riolo)

Appraisal by linear measurements has distinct
advantages over angular measurements
1. There are fewer variables to affect the
accuracy of the linear measurement, and
2. there is less error of measurement.
3. Angular changes are complex measurements
because in any angular measurement the
position of three points is involved.
4. The effect of angular changes also becomes
larger as you move away from the vertex of the
angle being measured.

• App – Bpp (5.2 ± 2.9 mm in women
4.8 ± 3.6 mm in men)
• App – Pogpp (2.5 ± 4.3 mm for women
2.4 ± 5.4 mm for the men.)
• Mpp – Dpp
• Mpp – Pogpp
• The size of the bony chin Pog is highly variable
between persons hence greater range of values
observed for App-Pogpp and Mpp-Pogpp.
• Chin size and shape may be related to
secondary sexual characteristics.
• Pogonion is important in determining the facial
profile, especially in the adult.

• App-Bpp, App-Pogpp, Mpp-Dpp, and MppPogpp decrease during growth.
• Class I malocclusions App-Bpp (6 to 24 years)
2.5 mm in female
0.8 mm decrease in male.
The values for the persons with Class I
malocclusions from age 6 years onward were
within the normal adult range derived in this
study. This indicates that this method of analysis
may be applied as early as 6 years of age.

• Unlike Class II, Division 1 malocclusions, the
persons with Class II, Division 2
malocclusions had a greater decrease in the
App-Bpp
• Became slightly more protrusive than those of
the Class I sample with 0.5 mm more protrusion
for the women and 1.5 mm more for the men.
• Md values remained within normal range from
the age of 12
• Class II, Division 2 malocclusion is considered
to be a dental malocclusion with a strong genetic
component combined with a normal skeletal
pattern

Class II subdivision
• The mean values for Class II subdivision
subjects were within the range of normal.
This was not unexpected as this
malocclusion is frequently considered to
be a variation of Class I. Usually it is a
result of asymmetrical mesial drift of the
maxillary permanent first molar because of
premature loss of a primary second molar,
or unfavorable tooth eruption in the
maxillary arch.

Class III malocclusion
• In a Class III malocclusion from age 6 to 24
years because of a larger anterior growth of the
mandible, the maxillomandibular relation
measured considerably more in the negative
direction.
• Beyond the age of 12 years,, the measurements
became progressively smaller due to maturation.
Men show changes beyond age 18 years.
• Low FMA might be associated with a lower AppBpp measurement. This correlation is very weak
and statistically significant only in men.

• In determining the norms for the measurements
on palatal plane, a variance of one-half standard
deviation from the mean was selected. This
range was defined narrowly because in
malocclusions one is dealing with normal and its
variations so that measures of normal need to
have a narrow range to be able to differentiate
between the variations seen in malocclusions.
• There is no significant difference in the sagittal
jaw relation as indicated by the App-Bpp
measurement between the persons with Class I,
Class II, Division 2, and Class II subdivision
malocclusions. The persons with Class III and
Class II, Division 1 malocclusions were
significantly different from the normal.

Pitchfork analysis
- Lysle Johnston !996 JO
• Aim: Correction of molar relationship and overjet
— assessment of physical displacements
produced by growth and tooth movement:
• displacement of maxilla relative to cranial base,
• movement of maxillary dentition relative to
maxillary basal bone,
• translation of mandible relative to cranial base,
and movement of mandibular dentition relative
to mandibular basal bone.


• The so-called ‘pitchfork’ diagram provides
a convenient and logical means of
organizing and summarizing the various
components of change that come together
at the occlusal plane.


• Bodily translation of basal bone can move teeth;
surface changes cannot. The pitchfork analysis thus
requires that we measure skeletal change as actual
physical displacement, rather than apparent change
in the position of a landmark due to surface
remodelling.
• The change in the molar and incisor relationship can be
expressed as an exact algebraic sum if the component
displacements are measured in a comparable manner
and each is given a sign appropriate to its impact:
– positive if it would tend to correct a Class II molar relationship or
reduce overjet (with forward growth of the mandible or mesial
movement of the lower molars and incisors);
– negative, if it increases the overjet or moves the molar
relationship toward Class II (e.g. as with forward growth of the
maxilla or mesial movement of the upper dentition).

Advantages:
1. Allows comparisons of change between treatments and between
treatment phases, not only with respect to magnitude, but also
source (i.e. skeletal or dental).
2. It will always be internally consistent: the components of growth and
tooth movement, no matter how they are measured, will add up to
the total molar and overjet correction.
3. Regional superimposition on stable anatomical details aids to
standardize the position of landmarks in the bones whose
displacement is to be measured.
4. The impact of remodelling on surface landmarks does not affect the
measurements made.
Disadvantages:
1. Although growth and treatment interact in all 3 planes of space, only
a-p changes are considered (because of the author’s interest)
1. The analysis is based on tracings & superimpositions of shared
anatomical details that may differ from patient to patient so its
difficult to get a computer program for digitization to generate
tracings and to execute measurements.

Pitchfork analysis:
• Apical base change (ABCH)= the sum of
maxillary + mandibular translatory growth
relative to cranial base
• Change in molar relationship =ABCH + upper +
lower molar movement
• Change in overjet = ABCH + upper + lower
incisor movement.
The analysis is based on 3 superimpositions:
• Cranial base
• Maxilla
• Mandible

• Superimposition of the cranial base – along the
antr cranial base.
• S-Na change with local remodelling during
growth.
• So the superimposition is done along the
anterior half of sella turcica to foramen caecum
and the internal outline of the frontal bone. (de
Coster 1951)
• And also over the greater wing of sphenoid, the
cribriform plate, the orbital roofs. (Bjork)


Superimposition of the maxilla:
• Maxillary superimposition along ANS-PNS in with
registration on ANS or the lingual palatal curvature.
• The superior and inferior surfaces of the posterior hard
palate assist in orientation, and to minimize the
probability of gross errors in antero-posterior registration,
care should be taken to ensure that the PTM fissure of
the older tracing lies at or behind that of the younger.


• Mandible
Mandibular regional superimposition. Registration is
achieved by aligning the bony architecture of the facial
half of the symphysis orientation, by aligning the
mandibular canals or molar tooth germs. The
superimposition is used to carry both the fiducial line and
D point (the centre of the bony symphysis, by inspection)
through from one tracing to the other.


•

‘Fiducial lines’ are arbitrary straight lines several inches long marked
on either end with registration crosses.

•

Such lines are drawn adjacent to cranial base, maxilla, and
mandible of one tracing (say, from the middle of the series).

•

It is important to note that once a tracing has been used in a
superimposition, its fiducial lines are inviolate.

•

Once the fiducial lines have been transferred throughout the
series, they serve not only to record the superimpositions to
facilitate the process of measurement, but also to provide a
greatly simplified picture of change seen from the vantage
point of any of the three facial areas.

•

If, for example, the cranial-base fiducial lines are superimposed, the
separation of the mandibular and maxillary fiducial lines represents
the translatory growth—both in amount and angulation—of the jaws
relative to cranial base.


Measurement of change
• Based on the ideas of Wendell Wylie, Jacobsons ‘Wits’
analysis (Jacobson, 1975), and the analytic methods of
D. Harvey Jenkins (1955)
• The superimpositions are recorded by arbitrary
fiducial lines. Maxillary advancement relative to
cranial base (MAX) is measured at W; Mandibular
displacement relative to maxilla (ARCH) is measured
at D. Both measurements are executed parallel to
MFOP.


•

The pitchfork analysis uses a ‘functional’ occlusal plane (FOP) (Jenkins
1955) and defined as ‘...the average occlusal plane of the buccal teeth,
including canine and first permanent molar’

•

FOP is a best-fit line passing through the occlusal overlap in the region of
the first molars, premolars, and canines (especially when premolars have
been extracted).

•

Thus, it is insensitive to incisor movement, it is representative of the bulk of
the buccal occlusion, and it is relatively stable over time, although its
angulation with respect to cranial base tends to decrease slightly and
progressively as the mandible outgrows the maxilla.

•

the line (sic) is placed by inspection, either with respect to the radioopacities created by cuspal overlap or to the radiolucencies scattered
among cusps along the line of the occlusion

•

The resulting best-fit orientation then is copied through to the overlying
tracing. In general, the pre-treatment FOP tends to cant downward a few
degrees relative to DOP but at the end of treatment, however, the two lines
commonly coincide.


•

Jaw growth displacement relative to cranial base
To measure displacement of the maxilla relative to cranial base
(MAX), the maxillary fiducial lines are superimposed and the
separation of the W points is measured parallel to MFOP. maxillary
rotation impacts measurements of both maxillary and mandibular
growth/advancement: ‘clockwise’ rotation increases both;
‘anticlockwise’ rotation decreases both. On average, however,
maxillary basal rotation is minimal and thus its effect on the analysis
is: probably negligible.

•

Next, the separation of D-points (standardized in the two tracings by
mandibular regional superimposition) is measured parallel to MFOP.
This measurement represents apical base change (ABCH), the
growth/displacement of the mandible relative to maxillary basal
bone.

•

Given the usual pattern of facial growth in which the mandible
‘outgrows’ the maxilla, ABCH commonly is positive. It should be
emphasized that this displacement of D-point can be due to growth,
a functional shift, or, more probably, mixture of both.

Tooth movement relative to basal bone
To trace the outline of a tooth, one has the option
of making a custom template from the best film
in the series or, indeed, from parts of several
films. One can add a long axis, contact points,
etc. and then use best-fit superimposition on the
film to transfer the template outline to each
tracing in the series. Although this method does
not guarantee that the teeth will be rendered
correctly, it standardizes details that should
remain constant (tooth form, size, long-axis
orientation, etc.) and thus serves to optimize the
measurement of change within a given series.


• Tooth movement is measured parallel to MFOP
superimposing within either the maxilla or mandible.
• Molar crown movement is measured at the mesial
contact point;
• Molar root movement from the point at which the long
axis is crossed by a line drawn between the apices of the
buccal roots.
Crown movement is the algebraic sum of root
movement and a component due to tipping.
Thus, the tipping component can be estimated by
subtracting root movement from crown movement.

•

Symphysis, mandibular canal, molar tooth-germs are used to
establish a mandibular superimposition and a single D-point is
transfered throughout the series.

•

Tooth movement then is measured with reference to an orientation
on MFOP and a registration on a perpendicular from MFOP erected
through D.

•

Displacement of the crown (mesial contact point) and roots of the
averaged first molars and the incisal edge of the averaged central
incisors is measured parallel to MFOP.

•

Orientation along MFOP requires a rotation of the corpus that
facilitates the measurement of molar movement, but which
eliminates the buccal-segment eruption that commonly occurs
secondary to forward growth rotation of the mandible.
Given the present emphasis on anteroposterior change, the
resulting ease of analysis more than offsets the loss of vertical
information.

•


• Molar relationship and overjet change
The change in molar relationship is measured by
registering on the mesial contact point of one
molar (upper or lower) and then measuring the
separation of the contact point of the other; the
change in overjet, by registering on the
averaged incisal edge of the upper or lower
incisors and then measuring the displacement of
the averaged incisal edge in the other arch. It is
helpful to execute the various measurements
with the aid of a magnifying glass and electronic
vernier calipers for internal consistency.


VTO
•
Growth and treatment prediction
1. Cranial base prediction
•
nasion and basion grow 1mm/ year each.
•
Traced superimposing on cc point
2. Mandibular growth prediction:
i)
Rotation: facial axis opens by 1* for every
- 5mm of convexity reduction
- 3mm of molar correction
- 4mm of overbite correction
- half the quantity for cross bite correction
•
DC descends 1mm/year
•
PM descends 2mm/year

1. Superimpose on condylar axis (DC – Xi)
draw the posterior border of ramus and
the lower border of mandible
2. Slide along the corpus axis (Xi – PM)
draw the new symphysis and mark the
Me.
Maxillary growth prediction
Divide Me – new Me distance into three
equal parts with two marks. Superimpose
on mark 1 and along the facial plane to
trace the palate ( except point A).

Point A prediction:
1.
With headgear pt A moves distally by 8mm
2.
With activator 2mm
3.
With torquing 1-2 mm
4.
Class II elastics 3mm
5.
Pt A moves mesially 2-3mm with facemask and class III elastics.
For every mm distal movement Pt A descends down by 0.5mm.

Occlusal plane prediction:
1.
Superimpose old Me on mark 2 and tilt the tracing to parallel the
mandibular plane.
2.
OP tips down (clockwise) for class III correction
3.
Anticlockwise for class II correction


•
1.
2.
3.
4.
5.
6.
7.

Dentition prediction:
Superimpose on corpus axis at Ptm and mark the lower incisal
edge 2mm ahead of A-Pog line and 1 mm above the OP.
Draw the ideal LI at 22* to A-Pog.
If a compromise in protrusion should occur then for every 1mm,
2* proclination is to be reduced.
Lower molar normally grows 2mm mesially for every 1mm
eruption.
Upper molar is drawn in class I relation according to the lower
molar position.
Draw UI with ideal 131+/- 10* to LI.
In case of open bite correction interincisal angle is placed at 141*
and 121* for deep bite.


Soft tissue prediction
Nose prediction:
1.
Superimpose nasion along the N-Pog line to trace the bridge of the nose.
2.
Place ANS along the palatal plane and move back by 1mm per year to
trace the nose tip.
Soft tissue Point A
1.
Superimpose on N-Pog and OP
2.
Mark old and new upper incisal tips
3.
Divide the distance into three parts
4.
Superimpose new incisor at mark 1 to trace the upper lip and soft tissue
A point.
Soft tissue B point:
1.
Bisect the new overjet and overbite and superimpose the UI at that point
and trace the lower lip.
2.
B’ is inferior to the original B’ because recontouring drops the lip down.
3.
Variations:
Increased lip drop is found in opening the bite and with correction of lip
strain.

Skeletal Maturity Indicators


Standing height
1. Statural height and hand-wrist skeletal maturation in both sexes are
significantly related. Maturity scores of girls at age 13 correlate best
with velocity of height between the ages of 13 and 14 years.
Maturity scores of boys at age 16 correlate best with velocity of
height between the ages of 15 and 16 years.
2. the correlation coefficients were relatively small between height
velocity and facial dimension velocity to be statistically significant.
The correlation coefficients between skeletal maturity scores and
changes in facial dimension were even smaller.
Therefore the relationship between acceleration and deceleration in
growth of specific craniofacial dimensions and statural height or
skeletal maturity is not clinically significant for prediction. However, it
may be used as a factor for consideration in diagnosis and
treatment planning in an individual case.
Sagittal jaw relationships are difficult to evaluate because of rotations
of the jaws during growth, vertical relationships between the jaws
and the reference planes, and a lack of validity of the various
methods proposed for their evaluation.
- Moore & Moyer, AJO ‘90

STANDING HEIGHT.
• The mean age for the maximum growth velocity from 8 to 17 years was 13.0
years for boys and 10.8 years for girls.
• The mean age of least growth velocity immediately prior to the age of
maximum growth velocity was 10.1 years for boys and 8.5 years for girls.
• The minimum occurred an average of 3.0 years before the maximum for
boys and 2.3 years for girls.

(1) the growth profile of height was significantly different from that of
the parameters describing mandibular length and relationship
(2) the changes in standing height are significantly different in the
maximum, premaximum, and postmaximum periods of growth in
both males and females
(3) the changes in mandibular length (Ar-Pog) are significantly different
in the three periods
(4) the changes in mandibular relationship were not significantly
different in the maximum and premaximum periods in either males
or females, while the magnitude of change in the postmaximum
period tended to be smaller than the other two periods
(5) autocorrelation analysis revealed that the growth profile of height
was found to have little predictive value in determining the growth
profile of any of the mandibular parameters except for Ar-Pog for
females.
-Bishara

AJO 1981

Conclusion
• Most observers consider cephalometric and plaster cast
records as static reproductions, but both have functional
analysis potential if used correctly.
• Much can be learned from them about the dynamics of
the stomatognathic system.
• Thus functional analysis is of equal importance to the
usual clinical examination and static, cephalometric, and
study model analyses.
• It is especially significant in treatment with functional
appliances because of the dynamic basis of therapy.


Thank you
Leader in continuing dental education


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