INDIAN DENTAL ACADEMY
Leader in continuing dental education
• Modern orthodontics is not only restricted to static evaluation of
the teeth and their supporting structures, but also includes all
functional units of the masticatory system (according to
Eschler,1952), i.e. the somatognathic system. Therefore
functional analysis constitutes a considerable part of clinical
examination, helps in etiologic evaluation of the malocclusion
and determining the type of orthodontic treatment indicated.
Three most important aspect of Functional analysis are:
• Examination of the postural rest position.
• Examination of the temporomandibular joint.
• Examination of orofacial dysfunction.
Examination of the relationship: Postural Rest PositionHabitual Occlusion
• Determination of the postural rest position.
• Registration of the postural rest position.
• Evaluation of the relationship: postural rest position-habitual occlusion, in
three planes of space.
• In postural rest position, synergistic and antagonist 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.
The rest position should be determined with the patient
relaxed and sitting upright. Patient should be looking straight
ahead and the frankfurt horizontal plane parallel to the floor.
Determination of the postural rest position
• In order to determine the PRP, the patient’s orofacial
musculature must be relaxed. When the mandible is in PRP, it is
usually 2-3 mm below and behind the centric occlusion. The
space between the teeth is referred to as the freeway space or
Several methods are available to determine the postural rest
• Phonetic exercises.
• Command methods.
• Noncommand methods.
• Combined methods.
• Patient is told to pronounce certain consonents or words
repetitively e.g. Mississippi. The mandible returns to the postural
resting position 1-2 seconds after exercise, then dentist gently
parts the lips to observe the interocclusal clearence and tongue
posture. In mixed dentition language habits vary and not
stabilized so this method is less used as prime determinants.
• The patient is asked to perform selected functions; the mandible
returns to the PRP after each function. Usually, having the
patient lick the lips and then swallow produces the desired
relationship as mandible returns to PRP with in 2 secs after
• In noncommand method the patient has no idea of the
parameter being examined. Careful observations are made as the
patient talks, swallow, and turns the head while being questioned
on a number of unrelated subjects.
• This method usually provides the best reproduction of PRP in the mixed
• The patient performs a prescribed function e.g. swallowing and then relaxes.
After instructing the patient not to move, the clinician gently palpates the
submental muscles to assess whether they are relaxed. An intraoral
examination by observing the relationship of the canine is performed.
Normally the lower canine is 3mm below the upper canine. An interocclusal
space of 4mm may be considered normal.
Registration of the postural rest position of the
• Various methods are recommended for registration:
• Direct intraoral method.
• Direct extraoral method.
• Indirect extraoral method.
Direct intraoral method
• This method is performed by using a plaster core registration
similar to that sometimes used in prosthodontics. This
registration is not feasible in mixed dentition.
• Millimetric calipers can be used to record the intraocclusal space
in the canine or incisor area.
Direct extraoral method
• Direct caliper measurements can be made on the patient’s profile by
measuring the distance from soft tissue nasion to menton. This measurement
is done in both postural rest and habitual occlusion. The difference between
the two measurements constitutes the interocclusal clearance. The
disadvantage of this procedure are that the soft tissues reduces the reliability.
Indirect extraoral method
• This method is most reliable:
• Roentgenocephalometric registration.
• Kinesiographic registration.
• Two cephalograms are required, either in lateral or frontal projection
depending on how the question is formulated.
One radiograph in centric occlusion.
One with mandible in its rest position.
The rest position and freeway space can be determined by comparing the
• The mandibular kinesiographic, according to jankelson(1984),
allows the mandibular rest position to be registered three
dimensionally. The position of the mandible is recorded
• A permanent magnet, which is fixed with rapid-setting acrylic to
the lower anterior teeth.
• A sensor system of six magnetometers mounted on the spectacle
• Every movement of the mandible and
the attached magnet out of centric
occlusion, alters the strength of the
magnetic field. These changes are
recorded by the sensors, processed in
the kinesiograph and displayed on a
The mandibular movements and rest
position are recorded two-dimensionally
on two pre-selectable levels. The
electronic circuitry also allows the rest
position to be recorded as threedimensional coordinates.
Evaluation of the relationship between rest
position and habitual occlusion
• The movement of the mandible from the rest position to full
articulation is analyzed three-dimensionally: In the sagittal,
vertical, and frontal planes.
• The closing movements of the mandible can divided into two
Free phase: Mandibular path from the postural rest to the initial or
premature contact position.
Articular phase: Mandibular path from the initial contact position to
centric or habitual occlusion. In case of functional equilibrium,
the articular phase does not occur.
• When closing from the rest position, the mandible may undergo
both rotational and sliding movement. The objective of this
analysis is to determine the amount and direction of movement
as well as the proportions of the rotational and sliding
components. The following movements of the mandible from
the rest position to habitual occlusion must be differentiated for
• Pure rotational movements
• Rotational movement with an anterior sliding component.
• Rotational movement with a posterior sliding component.
Evaluation in the sagital plane
• Class II malocclusions. Treatment prognosis for functional appliance therapy
depends on the analysis of relationships and the determination of the path of
• 1. In classII malocclusion without functional disturbances the path of closure
from rest to occlusion is straight up and forward, with a hinge movement of
the condyle in the fossa. These are true class II malocclusions
• 2. In class II malocclusion with
functional disturbances a rotatory
action of the condyle in the fossa from
postural rest to initial contact is
evident. From initial contact to full
occlusion, condylar action is both
rotatory and translatory up and
backward. As Boman and Blume
(1952) showed in their reserch, this
type of activity is most common,
particularly in excessive overbite cases.
This type of class II cases appears
more severe than it actually is sagitally.
And have a good prognosis.
• 3. In class II malocclusion with
functional disturbances in which the
path of closure is up and forwards,
mandible is anteriorly displaced from
the initial contact as the cusp guide the
mandible into a forward position, with
translatory movement of the condyles
down and forward. Rare condition
illustrated by Woodside. And this
condition is more severe than as it
appears with the teeth in occlusion,
having a poor prognosis.
• CLASS III MALOCCLOSION. Hinge-type of condylar movement
is often associated with straight path of closure. The possibility of successful
functional appilance therapy of this problem exist only if the magnitude of
sagital dysplasia is not too great and the therapy is began in the early mixed
• If the path of closure is up and back the prognosis is poor.
• In class III malocclusion with the anterior displacement that creates an up
and forward path of closure, the prognosis is much better and the treatment
success is possible, even in permanent dentition
• Some times a skeletal class III malocclusion is partially compensated by labial
tipping of the maxillary incisors and lingual tipping of mandibular incisors.
Because of the extreme tipping possible an anterior sliding movement into
occlusion can occur. Uprighting the incisors into their proper axial
inclinations results in severe class III sagital tooth relationship. Treatment
with orthodontic means is difficult because dentoalveolar compensation is
not possible; as incisors are already overcompensated before treatment and
orthognathic surgery should be considered. This type of malocclusion is
reffered to as pseudo-forced bite.
Evaluation of path of closure from postural
rest to habitual occlusion in vertical plane
• This evaluation is of special interest in the assessment of therapeutic potential
in deep overbite cases. Two types of deep overbite can be differentiated.
• 1. True Deep Overbite.
The true deep bite with a large interocclusal clearence is caused by
infraocclusion of the posterior segments. It often results from a lateral tongue
posture or tongue thrust habit. Treatment in the mixed dentition periods
requires the elimination of the enviromental factors inhibiting eruption of
Prognosis is good in a true deepbite problem with a vertical growth pattern. And
the prognosis is fair with horizontal growth pattern.
• 2. Pseudo-deep overbite with a small
interocclusal space already has normal
eruption of the poserior segment teeth. Some
class II div. 2 malocclusion that produce
gummy smile and poor lip line relation fall
into this category. The amount of
interocclusal clearence is a distinguishing
criterion. Clinician must intrude the incisors
with slight extrusion of molars; it results in an
increases facial height and further TMJ
problems. The clinician must derive the
maxillary molars distally to control the vertical
dimension. Cases with pseudo-deep bite with
horizontal growth pattern have poor
Evaluation of the relationship between rest position
and habitual occlusion in the Transverse Plane
• The position of the midline of the mandible is observed while the jaw is
moved from the postural rest to habitual occlusion. Depending on the
functional analysis two types skeletal mandibular deviation can be
• 1. LATEROGNATHY
• 2. LATEROCCLUSION
• LATEROGNATHY: The center
of the mandible is not aligned with
the facial midline in rest and in
occlusion. These dysplasias
constitutes true neuromuscular or
anatomical asymmetry. A lateral
cross bite with laterognathy is
termed true cross-bite. The
prognosis is unfavorable for causal
• LATEROCLUSION: The skeletal
midline shift of the mandible can
be observed only in occlusal
position; in postural rest position
both midlines are well aligned. The
deviation is due to tooth guidance
(functional non-true malocclusion).
EXAMINATION OF THE
• The objective of this aspect of functional examination is to assess whether
incipient symptoms of TMJ dysfunction are present.
• These symptoms are important for two reasons:
1. Through the early elimination of functional disturbances, some incipient
TMJ problems can be prevented or eliminated. This is an indication for early
2. During functional therapy the condyle is displaced or dislocated to achieve
a remodeling of the TMJ structures and a change in muscle function. If the
temporomandibular structures are abnormal at the start and hypersensitivity
is a problem, the possibility of exacerbating the symptoms exist.
• AUSCULTATION: is carried out with a stethoscope, clicking and crepitus in
the joint may be diagnosed during anteroposterior and eccentric movements
of the mandible.
• JOINT CLICKING IS DIFFERENTIATED AS FOLLOWS:
1.Initial Clicking: is a sign of retruded condyle in relation to the disc.
2.Intermediate Clicking: is a sign of unevenness of the condylar surfaces and
of the articular disc, which slide over one another during movements.
3. Terminal Clicking: occurs most commonly and is an effect of condyle being
moved too far anteriorly, in relation to the disc, on maximum jaw opening.
4. Reciprocal Clicking: occurs during opening and closing, and expresses an in
coordination between displacement of the condyle and disc. Clicking of the
joint is rare in children.
• PALPATION OF THE TEMPOROMANDIBULAR JOINT: During
opening maneuvers will reveal possible pain on pressure of the
condylar areas. Besides the right and left condyles can thus be checked
for synchrony of action.
Palpation – pain on pressure of the
condylar areas. Right & left condyles
checked for synchrony of action.
* Lateral palpation of TMJ
– Slight pressure on the condyloid
process with the index finger.
* Posterior palpation of
TMJ – Position the little finger in the
external auditory meatus and palpate
the posterior surface of the condyle
during opening and closing.
Palpation of lateral pterygoid
- is palpated close proximity to
the neck of the condyle and the
joint capsule, cranially behind the
maxillary tuberosity. It is carried
out with mouth open and
mandible displaced laterally.
Palpation of Temoporalis
Bilaterally & Extraorally
Palpation of masseter muscle
– Superficial massater muscle is palated beneath the eye, inferior
to zygomatic arch.
- Deep portion is palpated on the same level, 2 finger width infront
Recording of the maximum inter incisal distance:
Maximum jaw opening – distance between incisal edges of the upper and
lower central incisors are measured with Boley gauge. It is usually 40-45mm.
In over bite cases this amount is added to the obtained value whereas in open
bite it is subtracted. In cases with TMJ dysfunction, hypermobility is often
registered in the initial stages and limitation in the later stages.
Opening and closing movements of the mandible:
• The opening and closing movements of the mandible as well as its protrusive,
retrusive and lateral excursion are examined as part of the functional analysis.
The size and direction of these actions are recorded during clinical
examination. Deviations in speed can only be registered with electronic
• The first signs of initial temporomandibular joint problems include deviations
of the mandibular opening and closing paths in the sagittal and frontal planes.
In patients with malocclusion and malaligned teeth, disturbances in
mandibular movement are the result of an asynchronic pattern of muscle
contractions. The characteristic movement deviations include incongruency
of the opening and closing curves and uncoordinated zigzag movements. The
“C” and “S” types of deviations are typical signs of functional disturbances.
Occlusal analylsis on an articulator is mostly not necessary in adolscents. It is only
indicated in patients with manifest symptoms of temporomandibular joint
Pattern of mandibular movements
during opening and closing maneuvers:
Opening and closing paths in sagittal
plane.1. opening and closing arcs cross
2. The opening movements show
3. The closure pattern is straighter and
OPENING AND CLOSING ARCS
IN HORIZONTAL PLANE: 1. the
opening path is pathologically C-shaped
At the end of the closing movement,
the mandible shifts slightly toward the
OPENING AND CLOSING PATHS
IN THE FRONTAL PLANE. The
extent of jaw opening is normal and
mandible towards left due to occlusal
Temporomandibular joint- Radiographic
• Only in limited cases radiographic examinations indicated for
patients with functional disturbances of the temporomandibular
• When analyzing the radiographs following findings are
1. Position of the condyle in relation to the fossa.
2. Width of the joint space
3. Changes in shape and structure of the condyle head or the
Adolescents with class II, Div. 1 malocclusion and lip
dysfunction (lip sucking or sucking) are most frequently affected
by TMJ disorders.
Normal mature swallowing takes place without contracting the muscles of facial
expression. The teeth are momentarily in contact and the tongue remains inside the
Abnormal swallowing is caused by tongue thrust, either as a simple thrusting action or
as tongue-thrust syndrome. The following symptoms distinguish this syndrome:
1. Protrusion of the tip of the tongue
2. No contact of the molars
3. contraction of perioral muscles during deglutitional cycle
During their first few years, infants swallow viscerally. i.e. with the tongue between the
teeth. As the deciduous dentition is completed, the visceral swallowing is gradually
replaced by somatic swallowing. If visceral swallow persists after fourth years of age, it
is considered OROFACIAL DYSFUNCTION.
Phases of swallowing
• During the first stage food is collected in
the foremost part of the mouth, in front of
the retracted tongue. The posterior arched
part of the dorsum is in contact with the
soft palate. The lips are not in contact and
the teeth are not occluding.
1st part of movement.
During the second phase of swallowing, i.e.
the transporting stage, the tip of the tongue
first moves upward and the anterior section
of the dorsum is depressed.
2nd part of movement.
The entire anterior section of the tongue
then moves upward and the central section
of the dorsum is depressed. This peristalsis
transports the bolus rearward.
• TRANSPORTING STAGE
3rd part of movement
At the end of the transporting stage, the
soft palate is displaced upward and
rearward. The lip musculature contracts
simultaneously, the lips are together, the
mandible is raised and the teeth come
• THIRD SWALLOWING STAGE
The dorsum of the tongue is depressed even further during the third stage so
that the bolus can pass through the oropharyngeal isthmus; simultaneously
the anterior part of the tongue is pressed against the hard palate, thus forcing
more food rearward. Passavant’s pad and soft palate form the
palatopharyngeal seal and close the nasopharynx. The teeth are in full
occlusion and the lips are in contact.
• FOURTH SWALLOWING STAGE
During the fourth stage of the swallowing act, the dorsum of the tongue is
moved further upward and rearward against the soft palate and squeezes the
remaining food bolus out of the oropharyngeal area.
FINAL STAGE OF SWALLOWING
• Once the swallowing act has been completed the mandible returns to its rest
VISCERAL OR INFANTILE
Jaws apart with tongue between gum
It is triggered off by sensory
interchange between the lips and tongue.
Peristalsis commences in the vestibule
• Associated with tongue and mandibular
• The transverse section shows that the
tongue is positioned low in mouth and
that the central furrow is depressed.
• SOMATIC SWALLOW:
• As swallowing is triggered off by
contraction of mandibular elevators, the
teeth occlude momentarily during the
swallowing act and the tip of the tongue is
enclosed in the oral cavity.
• Transverse section shows that the dorsum
of the tongue is less concave and
approaches the palate during swallowing
Tongue thrust has an important effect on the etiopathogenesis of malocclusion.
The thrust may take place in the anterior or lateral regions or can be complex
ANTERIOR OPEN BITE
Open bite in a deciduous dentition, caused by a
tongue dysfunction as a residuum of a sucking
The tongue is positioned forward during
functioning, thus impeding the Vertical development
of the dentoalveolar Structures.
LATERAL OPEN BITE
In this type of open bite the occlusion on
both sides is supported only anteriorly and by
the first molars.
The tongue thrust between the teeth laterally.
The tongue dysfunction occurs in conjunction
with a disturbance in the physiologic growth
processes around the first and second deciduous
COMPLEX OPEN BITE
Severe vertical malocclusion. The teeth occlude
only on the second molars. Tongue thrusting
occurs during function.
TONGUE DYSFUNCTION AND
In mandibular prognathism, the downward
forward displacement of the mandible often
causes an anterior tongue-thrust habit.
The significance of tongue thrust and its role in the etiology of malocclusion have
been evaluated by no. of authors. One school of thought asserts that the tongue
thrust is the consequence of an abnormal morphologic relationship, an adaptive
phenomenon. Other investigators like Andrew, Hopkins consider tongue thrust a
primary etiologic factor for malocclusion. Abnormal tongue posture and function
can be primary factors as consequences of retained infantile deglutition patterns or
other abnormal oral habits, but they also may be strictly secondary or adaptive to
unfavorable morphologic pattern.
So tongue thrust may be considered primary or secondary.
1. The primary dysfunctions cause malocclusions and the treatment must concentrate
on eliminating the orofacial dysfunction.
2. Secondary dysfunction can be considered an adaptive phenomenon to an existing
skeletal or dento-alveolar deviation in the vertical development. These secondary
abnomalities usually correct spontaneously while the morphological discrepancies
are being treated.
CAUSES OF TONGUE DYSFUNCTION
CAUSES OF DYSFUNCTION
• PRIMARY TONGUE DYSFUNCTION
IN CONJUCATION WITH HYPERPLASTIC
TONSILS. A retracted tongue would touch
infected, swollen tonsils if these were to
protrude far out of the surrounding structures.
in order to avoid painful sensation and to
keep the oral airway open the mandible is
dropped and the tongue postured forward.
Moderately swollen palatine tonsils which
protrude significantly from the tonsillar sinus.
ADAPTIVE TONGUE DYSFUNCTION.
After loss of teeth, the tongue is used to fill the gaps, thus
Sealing the oral cavity i.e. compensatory dysfunction.
ADAPTIVE DYSFUNCTION WITH SKELETAL
Cephalogram of an open bite due to rickets. The tongue
Dysfunction is an adaptation to the skeletal and
OPEN BITE DUE TO RICKETS. The skeletal and
dentoalveolar open bite is aggravated by the adaptive tongue
CONFIGURATION OF THE CRANIOFACIAL AND
• The morphology of the facial skeleton and the effects of tongue thrusting are
correlated to a certain degree.
• Horizontal growth pattern in conjuncation
with tongue thrusting usually results in
bimaxillary dental protrusion.
• In vertical growth pattern with tongue
thrust the lower incisors are often are in
lingual inclination. From the differential
point of view it is important to clarify
both the skeletal relationship and the
tongue dysfunction in order to localize
the results of the abnormal tongue
METHODS OF EXAMINATION
• Various methods can be used to examine tongue dysfunctions. The different
types of clinical examinations are : electronic recordings, electromyographic
examinations, recording of the pressure exerted by the tongue intraorally,
roentgenocephalometric anaylsis, cineradiography, palatographic,
• The position and size of the tongue in relation to the available space is
assessed by using roentgenographic cephalometrics. However, in most
orthodontic cases, registrating the position of the tongue is more important
then determining its size.
It involves recording the contact surfaces of the tongue with the palate and teeth while
the patient produces speech sounds or performs certain tongue functions.
A thin layer of contrasting precise impression mat. On
Patients tongue. Once the consonants are pronounced
Patalogram is documented photographically.
Accurate prononciation of “S”. During articulation the
mandible is lowered and pushed forward. The tongue
rests on the teeth and alveolar processes, and a groove
is formed in the center throgh which the air stream is
INTERDENTAL SIGMATISM (lisping).
During this defective pronounciation of the “S”
sound, the tongue is usually protruded.
PALATAL SIGMATISM. This abnormal
pronounciation is caused by an unphysiologic
friction noise between tongue and hard palate.
LATERAL SIGMATISM ON THE LEFT SIDE.
The tongue rest on the anterior teeth. The column
of air escapes on the left side.
BILATERAL SIGMATISM. Palatogram of this type
of defective articulation in a patient with microglossia.
SIGMATISM DUE TO LATEROFLEXION TO
THE LEFT SIDE. The tip of the tongue is raised
too high and rest on upper incisors. The tip of the
tongue deviates to the left.
The size and shape of tongue have many variations- bulky and short, narrow and
long and wide and long.
Numerous clinical methods may be used to assess tongue size. The most
common is to check whether the patient can touch the chin with the tongue tip.
A positive result is considered an indication of macroglossia.. Other symptoms
1.The oral cavity is filled by the tongue mass
3.Indentations on the tongue periphery.
4.Spaces exist between incisors, which are procumbent.
5.Tongue is protruded with open bite present.
But in the case with microglossia or hypoglossia, the protruded tongue tip reaches
lower incisor at best and the floor of the mouth is elevated and visible on each
side. Other features:
1. The dental arch is collapsed and reduced in size
2. Extreme crowding is seen in the premolar region.
3. A severe class II relationship is usually evident.
4. Third molars are usually impacted at the angle of the jaw.
5. In severe cases of microglossia and aglossia posterior segments are tipped so
markedly to the lingual that they touch each other in the midline.
Some investigators hold that the tongue posture is more important than tongue
function. The posture of the tongue can be flat or arched, protracted or
retracted, narrowed and long, or spread laterally and shortened. Tongue
posture is examined clinically with the mandible in the postural rest position.
Sagittal cephalometric registration of this relationship also is possible.
From the basal tongue posture at rest position an assessment of three regions-root,
dorsum, and tip was made and disclosed the following:
1. The root is usually flat in cases of mouth breathing, deep overbite caused by a
small tongue; in all other cases, slight contact of the tongue usually occurs with
the soft palate.
2. In class II div. I malocclusion with deep overbite the dorsum of the tongue is
arched and high; in all other malocclusion the tendency exist for the tongue to
3. The tip of the tongue is usually retracted in class II div. I, but in all other
categories of malocclusions a slight anterior gliding of the tongue tip occurs as
mandible moves into postural rest position.
METRIC EVALUATON OF TONGUE POSTURE
Assessment of tongue
size from metric analysis
requires measurement of
the distance between the
superior tongue surface
and the roof of the
mouth. This is done
along the seven
constructed lines. These
the relative size of the
tongue. Only if the entire
oral cavity is filled can a
diagnosis of macroglossia
TRACING OF THE
ANALYSIS ON THE
Marking of the contours
of the bony palate and
dorsum of the tongue.
Left. The morphologic
relationships in case of
Right. Relationship in
case of a downward
forward tongue posture.
TEMPLATE FOR METRIC ANALYSIS OF TONGUE POSITION.
Transparent plastic template with an inscribed millimeter scale for analyzing the
position of the tongue on the lateral cephalogram. The template is oriented on
the point O.
The etiology of lip dysfunction is similar to that of tongue habits and is
assessed in relation to the configuration and functioning of the lips.
Configuration of lips:
The configuration of lips differs a great deal and can be classified as follows :
1. Competent lips. The lips are in contact when
the musculature is relaxed.
2. Incompetent lips. Anatomically short lips with a
wide gap between the upper and lower lip in relaxed
Consciously closed lips. Incompetent lips can only
be closed by increasing contraction of the
orbicularis oris and mentalis muscle.
3. POTENTIALLY INCOMPETENT LIPS.
Upper incisors are labially tipped and their incisal margins
interpossed between the lips preventing the normal lip seal.
CONCIOUSLY CLOSED LIPS. Lip contact is achieved
without increased contraction of the perioral
4. EVERTED LIPS. Frontal and profile views with lip closed.
Due to weak tonicity of the lip musculature, these patient
often exhibit bimaxillary dental protrusion.
Various habits of lips can be divided into:
1. Lip sucking
2. Lip thrust
3. Lip insufficiency
Lip dysfunctions can be observed while the patient is speaking and swallowing.
The lower lip often shows variations of dysfunction with regard to the tip of the
tongue. The lower lip and tip of the tongue are often in contact. In such cases, the
lower lip is sucked in and is pressed against the tip of the tongue. It is a symptom
of orofacial dysfunction. Visual evidence of mentalis muscle activity is also
LIP SUCKING. Extra oral findings
Lower lip is positioned behind the
upper incisors, this malpositioning
occurs in conjunction with hyper
Lat. Cephalogram indicates that
lower lip dysfunction causes further
protrusion of the upper incisors. And
impedes the forward development of
the anterior alveolar process.
Characteristic profile of the lower
third of the face in a case of
hyperactivity of the mentalis muscle.
Lat. Cephalogram. This type of lip
habit is combined with lingual
inclination of the incisors.
In cases of cheek sucking and cheek biting, the soft tissues are interposed between
the teeth, which promotes the formation of the lateral open bite or deep over bite.
Increased lateral pressure by the cheek musculature impedes the transverse
development of the jaws.
HYPERACTIVITY OF MENTALIS MUSCLE:
• The deep mentolabial sulcus is characteristic of the hyperactive mentalis
muscle. This muscle behavior impedes the forward development of the
anterior alveolar process in the mandible.
The mode of respiration is examined to establish whether the
nasal breathing is impeded or not. Chronically disturbed nasal
respiration represents a dysfunction of the orofacial musculature;
it can restrict development of the dentition and hinders the
Causes leading to mouth breathing:
• Chronic respiratory obstruction.
• Mechanical obstruction.
• Size of the nostril.
• Pharyngeal tonsils or adenoids (adenoid facies).
• Greater effort required to breath through the nose – tortuous nasal passages.
• Partial blockage of the nose leads to resistance of airflow – person shifts to
Clinical findings of patients
with oral respiration :
1. High palate
2. Narrowness of upper arch
4. Hyperplasia of the gingiva
5. Adenoid facies
6. Rotation of mandible laterally
7. Increased overjet.
PATTERN OF FACIAL MORPHOLOGY:
The configuration of the facial skeleton and oral respiration are correlated to
certain degree. Impeded nasal breathing shows a higher frequency in facial types
with vertical growth tendency. Proliferation of the adenoids is more common
and more pronounced in patients with oro- nasal respiration. The incidence of
hypertrophied tonsils is also increased in this group.
Slight proliferation of
lymphoid tissue. On upper
and rear wall.
occupying half of the
occupying most of
Two different tongue posture are possible in case of oronasal respiration:
The tongue is flat and its tip is behind
the lower incisors. This type is often
encountered on conjunction with
a anterior cross bite.
The tongue is flat and retracted.
This type of abnormal tongue posture
is common in cases with oral
respiration and disto occlusion.
EXAMINATIONOF BREATHING MODE:
Following are the various clinical methods of examination:
1. Cotton pledget test
2. Mirror test
3. Observation of nostrils
Differential diagnosis must be used to determine whether the problems in nasal
respiration are due to an obstruction of the upper nasal passages or habitual oral
respiration. The orthodontic treatment planning for patients with restricted nasal
respiration must be related to diagnosis of the ENT specialist.
The health of oral hard and soft tissues must be assessed for potential orthodontic
patients as for any other. It is important that any dental caries or pulpal pathology
be treated before orthodontic therapy. A thorough peridontal evaluation is an
important part of orthodontic examination. Potential or actual mucogingival
problems are of special interest. Any orthodontic examination should include
gentle probing through the gingival sulci, not to establish pocket depths but to
detect any areas of bleeding. Bleeding on probing indicates active disease, which
must be brought under control before other treatment is undertaken. Inadequate
attached gingiva around crowded incisors indicates the possibility of tissue
dehiscence developing when the teeth are aligned, especially with nonextraction
• Radiological examination is absolutely essential in orthodontic diagnosis.
In clinical practice, the type and number of radiographs should, subject
patient to as little radiation exposure as possible while providing maximal
information at the same time. Radiographs of the hands and
temporomandibular joints are not among the routine requirements of
ENLARGED PANORAMIC VIEW
MENTAL SPINE VIEW
The straight posteroanterior view is so
named because the x-ray beam passes in a
posterior to anterior direction through the
skull. This projection is used to examine
the skull for disease, trauma, or
developmental abnormalities. It also
provides good record for detecting
progressive mediolateral dimension
changes of the skull, including asymmetric
growth. It also offers good visualization
of facial structures, including the frontal
and ethmoidal sinuses, nasal fossae and
Cephalometrics is a tool for dealing with variations in craniofacial morphology. Its
purpose is always comparison. In practice these comparisons are made for one
of five reasons.
1. To describe morphology or growth.
2. To diagnose anamolies.
3. To predict future relationship.
4. To plan treatment.
5. To evaluate the results of the treatment.
1.DESCRIPTION: Cephalometric description aids in the specification, localization,
and understanding of abnormalities. It comprises of three kinds of comparisons.
a. comparison with standard.
b. comparison with ideal.
c. comparison with self.
a. Comparison with standard: Research population provide extensive statistics for
details of cranifacial morphology and growth. Measures of central tendencymean, median, and mode- are often used as norms with which an individual
patient is compared; in this sense, they present “normal” form.
b. Comparison with ideals: certain clinicians have also contrived subjective ideals
of facial form for use of clinical comparison. The difference between standard
and ideal is important. Standards are objective measures stastically derived from
populations. Ideals are arbitrary, subjective concepts of facial esthetics
represented with numbers.
c. Comparison with self: The patient may also be described by cephalometric
comparisons with his or her earlier cephalogram.
2. DIAGNOSIS: In orthodontics, diagnosis is determination of significant deviations
from the normal. The diagnostic purpose of cephalometrics is to analyze the nature of
the problem and to classify it precisely. For instance, cephalometric diagnosis leads to
assignment to facial types and classes. Since some aspects of facial morphology are
relatively stable under treatment, cephalometric diagnosis contains a strong
component of prediction.
3. PREDICTION: Description, diagnosis, and prediction are conceptually and
practically quite different. To make a cephalometric prediction is to observe certain
quantities, assumes they will behave in determinate ways, and extrapolate the
consequences. The clinician would like to be able to predict well several important
aspects of craniofacial growth, for example, changes in principal directions of growth,
or the cessation of such periods. Therefore, the most practical prediction currently
involves the exploitation of “craniofacial constants” to supply predictions of shape
approximately independent of net amount of growth remaining.
4. PLANNING TREATMENT:
If the clinician can describe, diagnosis, and predict craniofacial morphology, a clear
plan of orthodontic treatment can be derived. All treatment occurs after the initial
cephalogram in a face which is constantly changing. Clinicians use the cephalogram
to define expected changes resulting from growth and treatment is applied
5. EVALUATION OF TREATMENT RESULTS:
Successive cephalogram are used to discern the progress of treatment and to plan
any changes in treatment which may seem necessary. Evaluation of treatment
results is recurrent description and diagnosis.
OBTAINING THE CEPHALOGRAM:
A cephalometric apparatus consists of a cephalostat or head holder, an x-ray
source, and a cassette holder. Cephalostats are of two types. The BroadbentBolton method utilizes two x-ray sources and two film holders so that the subject
need not be moved between the lateral and posteroanterior exposures. Although
this method makes more precise three dimensional studies possible, it requires
two x-ray heads and more space and it precludes oblique projections.
The Higley method used in most modern cephalostats, uses one x-ray source and
film holder with a cephalostat capable of being rotated. The patient is
repositioned in the course of the various projections. This method is more
versitile, but care must be taken so that the horizontal relationship of the head
does not alter during reposition.
The x-ray sorce must produce sufficiently high voltage
(usually above 90 kVp) to penetrate the hard tissue well
and to provide good delineation of both hard and soft
structures. A small focal spot results in sharper
• For orthodontic diagnosis this is superior to all other radiographic methods.
One single film provides a total survey of the dental status and adjacent bony
structures of both jaws. It involves least exposure to radiation. A disadvantage
of this rotary laminographic technique is a possible distortion in the anterior
region. Some cases will, therefore, require supplementary radiographs, such as
an enlarged panoramic view or periapical view.
1. It provides an over all view of the teeth and the jaws.
2. It serves as a screening projection to identify odontogenic diseases and other
disorders that may be the source of TMJ symptoms.
3. Gross osseous changes in the condyles may be identified, such as asymmetries,
extensive erosions, large osteophytes, or fractures.
4.Useful aid in serial extraction procedures to study the status of erupting teeth.
LIMITATION: No information about condylar position, or function is
provided and mild osseous changes may be obscured.
1. No display of fine anatomic details
2. Unequal magnification
3. Geometric distortion in the anterior region
4. Occasionally presence of overlapping structures of cervical spine
ENLARGED PANOROMIC VIEW
• Advantage :- accurate imaging of anterior region
• Disadvantage :- distortion in the posterior region
Intraoral radiographs are the backbone of imaging. A full series of intraoral
radiographs (10 to 16 films) is required for assessment of the periodontal
state in adults. Otherwise periapical films are only indicated where the
panoramic view suggests possible pathological conditions. (e.g. congenitally
missing teeth or malposed tooth germs).
1. To confirm the presence or absence of teeth or supernumerary teeth.
2. To assess the extent of calcification and root formation.
3. To study the alveolar bone and periodontal ligament.
4. To study height and contour of alveolar bone.
5. To assess the axial inclination of roots.
6. To detect retained root fragments and root stumps.
7. To determine the size and shape of unerupted teeth.
1. Assessment of entire dentition requires much of radiation exposure.
2. Children may not allow placement of films.
3. They cannot be used in patients having high gag reflex and trismus.
• Displays relatively large segment of a dental arch.
• Used in following situations :-To precisely locate roots of supernumerary, unerupted, impacted canines and
-Localize foreign bodies in salivary gland ducts.
-Location,nature,extent and displacement of fractures.
MENTAL SPINE/GENIAL TUBERCLE VIEW
This is an occlusal view of the anterior section of the mandible to determine its
1,2,3 are the individual exposure position.
1. The double spine of the superior part of the
2. The unpaired spine of the inferior part as
well as the bilateral st. of the superior genial
tubercle in the center.
3. 3 bony spines , the bony contours of the
inferior genial tubercles .
• The tranpharyngeal projection provides a sagittal view of the medial pole of
the condyle. Because of the negative beam angulation, this view depicts the
medial aspect of the condyle. The transpharyngeal view provides limited
diagnostic information because the temporal component is not imaged well.
The transpharyngeal projection is effective for visualizing erosive changes of
the condyle rather than more subtle changes.
This projection is similar to the transmaxillary
projection in that both provide an anterior view
of the TMJ, perpendicular to transcranial and
transpharyngeal projections. The entire
mediolateral dimension of the articular
eminence, condylar head, and condylar neck is
visible, which makes this view particularly useful
for visualizing condylar neck fractures. The
morphology of the convex surface of the
condylar head can be evaluated, making this
projection a useful adjunct to transcranial and
transpharyngeal projection in the diagnosis of
the gross degenerative changes or other
It provides a sagittal view of the lateral aspect of the condyle and temporal
Because of the positive beam angulation, the central and medial aspects of the
joint are projected inferiorly, and only lateral joint contours are visible in this
projection. The transcranial projection is useful for identifying gross osseous
changes on the lateral aspect of the joint only, displaced condylar fractures, and
range of motion.
Conventional film-based tomography , also called body section radiography, is a
radiographic technique designed to image more clearly objects lying with in the
plane of interest. This is accomplished by blurring the images of structures lying
superficial and deep to the plane of interest through the process of motion
unsharpness. Conventional tomography now is applied primarily to high contrast
anatomy, such as that encountered in temporomandibular joint and dental implant
This technique produces thin image slices, permitting visualization of an anatomic
structures essentially free of superimpositions of overlapping structures. This
technique can provides a true condylar position and osseous erosive changes, and
is a valuable adjunct to plain film radiography.
Computed tomography is indicated when more information is needed about the
three dimensional shape and internal structure of the osseous components of the
joint. CT produces digital image slices in both the axial and coronal planes,
although coronal images are more useful. Three dimensional reformatted images
also can produced. These are useful for assessing osseous deformities of the jaws
or surrounding structures. CT cannot produce accurate images of the articular
disk.. CT may be considered for determining the presence and extent of ankylosis
and neoplasms and the extent of bone involvement in some arthritis, imaging
complex fractures, and evaluating complications from the use of silicon sheet
implants such as erosions into middle cranial fossa and ectopic bone growth.
ADVANTAGE:1. Accurate visualization of an area of interest is possible
2. The computer programming makes it possible to view the images in different
shade and densities.
3. CT is useful for diagnosis of diseases in maxillofacial complex, including
salivary gland and TMJ.
CT SCAN SHOWING
LESION IN MANDIBULAR
MAGNETIC RESONANCE IMAGING:
MRI uses a magnetic field and radiofrequency pulses rather than ionizing
radiation to produce multiple digital image slices. To produce an MR image,
the patient is placed inside a large magnet, which induces a relatively strong
external magnetic field. This causes the nuclei of many atoms in the body,
including hydrogen to align themselves with the magnetic field. After
application of an RF signal, energy is released from the body, detected and
used to construct the MR image by computer. MRI has several advantages
over other diagnostic imaging procedures.
1. It offers the best resolution of tissues of low contrast.
2. No ionizing radiation is involved.
3. The region of the body imaged in MRI is controlled electronically so a direct
multiplanar imaging is possible without reorienting the patient.
4. In diagnosing a suspected internal derangement of the TMJ and evaluating
the treatment of that derangement after surgery; identifying and localizing
orofacial soft tissue lesions; and providing images of salivary gland
MRI does not have hazards as it uses non-ionising electromagnetic
Anatomical details are as good as in C.T. scan.
Imaging of blood vessels, blood flow, visualization of thrombus is possible.
Time taken is more.
It is not used in patients with cardiac pacemaker.
Non visualization of bone makes it useless in bony lesions.
By definition, ultrasound has a periodicity greater than 20 KHz. Thus it is
distinguished from other mechanical waves forms simply by having a vibratory
frequency greater than the audible range. As the ultrasonic beam passes through
or intersects with tissues of different acoustic impedance, it is attenuated by a
combination of absorption, reflection, refraction, and diffusion. These sonic echo
waves are reflected back to transducer which are amplified, processed, and
ultimately displayed on the monitor. Consequently, not only changes in echo
pattern delineate different tissues, they also can be correlated with pathologic
changes in a tissue. Differentiation between a cyst and tumor can be done and in
visceral and somatic swallowing patterns.
Ultrasound image showing
parasagittal image of the TMJ area
showing the articular disk in its
normal location superior to the
condyle in the closed mouth
Thermography is a term given to methods of temperature pattern resolution and
analysis. The utility of thermography in diagnosis is based on the fact that disease
process and abnormal conditions may result in different temperature patterns
because of altered blood supply or presence of inflammation.
1. Diagnosing disease of the maxillofacial complex.
2. Determining tooth vitality.
3. Evaluating a case of atypical odontalgia
4. Assessing an internal derangement of the TMJ.
Arthorography is a technique in which an indirect image of the disk is
obtained by injecting a radiopaque contrast agent into one or both joint
spaces under fluoroscopic guidance. A perforation is detected by the flow of
contrast agent into the superior joint space from the lower space, and
adhesion are detected by the manner in which contrast agent fills the joint
space. After the joint space is filled, disk function is studied using the
fluoroscopy during the opening and closing movements. Arthorgraphy is
indicated when information about Disk position, function, morphology and
the integrity of the diskal attachment is required. The risk of this procedure
include allergic reaction to the nonionic iodine contrast agent and infection.
FINITE ELEMENT METHOD:
Albeit initially developed this methid for aeronautical engineers, the finite has
found its place in medical and dental research over the last few years. It was
originally developed for studying the stresses in the complex air frame. It can also
be used for vibration analysis, thermodynamic analysis, fluid flow and
distribution of electric and magnetic fields. The application of FEM most related
to orthodontics is the structural stress analysis. There is a plethora of studies in
orthodontic literature using the FEM. These include studies of wire
configuration, stresses in the periodontal ligament, determination of centers of
resistance and rotation of teeth with normal or reduced bone height, stresses on
TMJ, jaws and cranium, stresses in brackets and adhesives, design of ceramic
brackets and studies of craniofacial growth.
Using flash x-ray sources, gated cameras are triggered simultaneously with
each x-ray source in succession at the rate desired. The gated cameras can
be set for exposure times between 5 nanoseconds and 33 milliseconds. In
cineradiography, the idea is to freeze motion in a series of images to track
motion in discrete steps. It helps in recording motion of dynamic events
like swallowing pattern.
LIMITATIONS: The images captured by digital cameras that have poorer
spatial resolution than that of film.
steps involved in
Electromyography is a medical technique for evaluating and recording
physiologic properties of muscle at rest and while contracting. EMG is
performed using a instrument called an electromyograph, to produce a record
called an electromyogram. An electromyograph detects the electrical potential
generated by muscle cells when these cells contract and also when cells are at
• Structural basis of Emgram is – motor unit.
• Electrical potential developed by the activation of one motor unit is called –
motor unit potential.
• Lasts for 5 to 8 milli sec and has an amplitude of 0.5 mv.
• EP recorded from whole muscle shows smaller potentials if the force of
contraction is less.
• When force is increased,due to recruitment of more & more number of
motor neurons,larger potentials www.indiandentalacademy.com
1. Helps to distinguish primary muscle conditions from muscle weakness
caused by neurologic disorders.
2. It is used to find causes of muscle weakness, hyperactivity, paralysis,
involuntary twitching, and abnormal levels of muscle enzymes.
3. In severe class II Div. I cases the upper lip is hypofunctional. Thus during
swallowing, the lower lip extends upwards and forwards to force the maxilla
labially and a strong mentalis activity is seen. EMG can be used to study such
4. Abnormal buccinator activity in class II malocclusion.
5. Overclosure of jaws is associated with accentuated temporalis muscle
6. Children with cerebral palsy.
7. EMG can be carried out after orthodontic therapy to see if muscle balance is
Xeroradiography was invented by Chester F. Carlson in 1937. xeroradiography
employs reusable photoreceptor plate and ultimately produces an image on
paper. xeroradiographic head films is used for routine cephalometric analysis. A
xeroradiographic picture or print resembles a blue print, but it shows all tissue
densities with fine detail. Xeroradiography is primarily used for evaluation of
breast lesion, larynx and temporomandibular joint.
1. It can be viewed without transillumination.
2. It is not necessary to make the typical cephalometric planes and points be
traced and subsequent tracings paper applied directly over the original head
film thereby reducing tracing error.
3. All densities of soft and bony tissue are displayed in one picture
4. Intraosseous detail and soft-tissue boundary definitions are superior to the
5. Teeth are more readily visualized.
A bone scan looks for abnormalities in the bone and joints. The scan uses a large
camera called a ‘GAMMA CAMERA’. This camera picks up radioactivity. First the
radioactive substance is injected into the blood stream and radioactive substance
should be small amount, not enough to harm. The radionuclide travels through the
blood and collects in bones and more of it collects in areas where there is lot of
activity in bone. Activity means the bone breaking down or repairing it self. These
areas are picked out by camera and commonly called spots
Laser scanning provides a method of capturing the face for planning or
evaluating outcome of orthodontic or orthognathic treatment.
The scanning is performed using the Vivid 700 (Minolta, resolution : 400*400
pixels), a 3-dimensional scanner operating on a laser-light stripe triangulation
The patient is instructed to sit still
in a chair with facial muscles
relaxed and eyes and lips lightly
closed for 0.6 second during the
scanning( 1.0 m apart from
1) An accurate evaluation of pre- and post-treatment soft tissue facial
profile is possible.
2) The pre- and post-treatment superimposition provided visualization
of the treatment results.
3) A quantitative assessment of the soft tissue changes were possible
with the use of the color coding system.
4) The soft tissue facial profile could be evaluated in any direction.
5) Much more diverse information and measurements could be
obtained curved surface, volume, etc
6) Excellent & very easy & fast data acquisition was possible.
7) The accurate data could be used for resolution of medical disputes.
1. Safety related issues.
2. Inability to capture the soft tissue texture, which results in difficulties in
identification of landmarks.
Computerized videoimaging technology offers a mutual visual template by which
orthodontist can effectively communicate with patients, it also allows greater
potential for quantification of treatment plans which maximize chances of delivering
proposed treatment plan. In other words, coordination of calibrated profile images
permits precise measurements of bony and dental movements, and through the
application of algorithmic prediction ratios, images are produced that express the
expected surgical and orthodontic outcome.
Requirements are same of radiographic cephalometry plus control of magnification
or distortion introduced by hardware (i.e. camera, monitor, software and
USES: 1. Counseling of patient.
2. Treatment planning:
The purpose of calibrating the cephalogram to the profile video is:
a. Relate the underlying hard tissue to the overlying soft tissue.
b. Allow quantification of movements. By knowing where the teeth are in relation
to the face, judgments can be made about the basic changes needed for the
occlusal correction. Consideration can then be given to what other procedures
may be needed for the esthetic ideal.
c. Permit the treatment plan to be designed to match the patient’s wishes as closely
d. Allows realistic movements to be planned.
1. ORTHODONTIC DIAGNOSIS- RAKOSI
2. DENTOFACIAL ORTHOPEDICS – GRABER, RAKOSI AND
3. RADIOGRAPHIC CEPHALOMETRY- ALEXANDER JACOBSON
4. FUNDAMENTALS OF OCCLUSION AND
TEMPOROMANDIBULAR DISORDERS- J.P. OKESON
5. CONTEMPORARY ORTHODONTICS- W.R. PROFFIT
6. ORAL RADIOLOGY- WHITE AND PHAROAH
7. HANDBOOK OF ORTHODONTICS- ROBERT E. MOYERS
8. CURRENT PRODUCTS AND PRACTICES IN ORTHODONTICS –
M.Y. HAJEER AND MILLET (journal of orthodontics vol.31 2004)
9. ELECTROMYOGRAPHY AND ITS APPLICATION IN
ORTHODOTICS- MEENAKSHI IYER. CURRENT SCIENCE VOL.
10. CURRENT PRINCIPLES AND CONCEPTS-- GRABER AND
IF WE COULD KNOW
WHERE WE ARE AND
WHITHER WE ARE
TENDING, WE COULD
BETTER JUDGE WHAT TO
DO AND HOW TO DO IT