diagnosing disc position- does it matter in orthodontics /certified fixed orthodontic courses

Diagnosing Disc position
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

CONTENTS
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ANATOMY OF TMJ
DEVELOPMENTAL ANATOMY OF TMJ AND
DISC
DISC LIGAMENTS
FUNCTIONS OF DISC
CARTILAGE ASSOCIATED WITH JOINT
BIO-MECHANICS OF TMJ WITH RESPECT TO
DISC
IMPORTANCE OF DISC CONTOUR
DISC DISPLACEMENT AND ITS CAUSES
TYPES OF JOINT NOISES

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

TYPES OF DISC DISPLACEMENT DISEASES
DIAGNOSIS
HISTORY
CLINICAL EXAMINATION
AIDS
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TRANSCRANIAL RADIOGRAPHS
TOMOGRAPHS
CT
MRI
ARTHROGRAPHY
ARTHROSCOPY

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ITS RELATION TO ORTHODONTICS
OCCLUSAL INTERFERENCE AND TMD
MALOCCLUSION AND TMD
ORTHODONTIC AND TMD
FIXED APPLIANCE AND TMD
FUNCTIONAL APPLIANCE AND TMD
EXTRACTION AND TMD
ORTHOGNATHIC SURGERY AND TMD
REVIEW OF LITERATURE
TREATMENT
NON-SURGICAL METHODS
SURGICAL METHODS

INTRODUCTION






The study of TMJ and it’s relation to
orthodontics and occlusion has been and is a
topic of tremendous interest due to it’s
complexity coupled with lack of complete
knowledge which has initiated numerous
concepts, theories and treatment methods.
The most fascinating and complex system in
the body is craniomandibular articulation.
Although much has been learned over the
years, a lot more remains to be learnt about it.

ANATOMY OF TMJ


Each TMJ involves temporal articular tubercle
and anterior part of mandibular fossa above
and mandibular condyle below.
It is also called ‘diarthroidal’(consisting of
two articulating bony surfaces);
‘ginglymoid’(as it has hinge like movement
component).
In normal joint both hinge
and translation occures within the lower
compartment and only translatry movement in
superior compartment.

Fibrous Capsule :


Each joint is surrounded by short capsular fibers
stretch from condyle to disc and from disc to
temporal bone forming two joint capsules. Longer
bands extending from condyle to temporal bone may
be regarded as reinforcing fibers and are present only
on the lateral side of joint. capsules is attached above
anteriorly to the articular tubercle, posteriorly to the
lips of squamotympanic fissure and between these
two to the edges of mandibular fossa and below to the
condylar neck. Above the disc it is loose and below it
is tant.






Lateral
temperomandibula
r ligament :
Close to capsule, is
attached above to the
tubercle on zygoma’s
root, below to the lateral
surface and posterior
border of mandibular
condylar neck.



Sphenomandibular
ligament :
Medial to capsule,
descend from spine of
sphenoid and widening
to reach the lingula of
mandibular foramen.




Stylomandibular
Ligament :
Stretches from apex
and adjacent anterior
aspect of styloid process
to mandibular angle and
posterior border.


DISC


An oval plate of fibrous tissue.
Upper surface sagittally concavo-convex and
inferior concave surface.
Its circumference blends with fibrous
capsule, antero-medially the tendon of lateral
pterygoid. Posteriorly the venous plexus
separates upper and lower layers, upper
attaches to fossa’s posterior margin and lower
to back of condyle.





Term disk is preferred over meniscus because
latter refers to a semilunar structure that may
have central perforation which is considered
pathologic.
In centric relation, central portion of disk is in
contact superiorly with descending slope of
articular eminence and inferiorly with convex
articular surface of condyle. Therefore disk is
biconcave in shape with anterior and posterior
rims and medial and lateral rims. In midsaggital cut, disk consists of an anterior band,
intermediate zone and posterior band.

Post natal growth of disc is upto 21 years
and after 5th decade it shows degeneration.
It is described as avascular noninnervated fibro-cartilage.

From all aspect, one can see disk’s
adaptation to its function as a shock absorber.
Disk is a protector of bony component of the
joint



The majority of cells are fibroblasts, with some
chondrocytes, keratin sulfate (KS), Chondroitin 4sulfate (C4S) chondroitin 6-sulfate (C6S), hyaluronic
acid (HA) and link protein (LP) are essential
components of condylar cartilage and disk fibrocartilage. These glycosaminoglycans (GAGs) are
distributed mainly in load bearing areas. The negative
charges on GAGs attract water and allow the disk or
condylar cartilage to absorb the stresses by deforming
and leaking water. After relief from compressive
force, water content is restored and loaded tissues
returns back to its original shape.

Vessels and Nerve Supply
Auriculotemporal and messetric branch of
mandibular nerve.
Superficial temporal and maxillary
arteries.


DEVELOPMENTAL ANATOMY
OF TMJ AND DISC:


Temperomandibular joint begins to develop by
10th week of gestation from two separate
blastemas, one for temporal bone component
and one for condyle. Superior to condylar
blastoma, a band of mesenchymal cells
develops that will eventually differentiate into
the disk. The temporal and condylar
mesenchymal cells will differentiate into
osteoblasts, which lay down membrane bone.



In the centre of condyle, cartilage develops
which becomes secondary cartilage that
remains in condyle upto 27 years of age. It
contributes to the enlargement of condyle in
adulthood as a part of adaptive changes in
response to overloading.



The developing disc is highly cellular and
vascular. It continues anteriorly with
developing lateral pterygoid muscle and
posteriorly by a ligament with superior end of
Meckel’s cartilage, which will develop into
malleus of middle ear



The developing TMJ shows all components of
mature joint by the 14th week. It is interesting
to note that division of disk into anterior band,
intermediate zone and posterior band exist in
fetus, which indicates that its morphogenesis is
genetically determined. The fetal disk was
found to contain nerve fibres and blood vessels
at peripheries which disappear from disk but
remain at disk attachment after birth.



Developmentally disk, articular capsule and
lateral pterygoid muscles are all derived from
same mesenchymal mass. Instead of remaining
on outside of joint cavity, during development
articular disk enters the joint itself.
Studies indicated that disc did not evolve
directly with TMJ, but appeared as a relatively
late phylogenetic development after separation
between placental mammals from egg lying
mammals and marsupials.

Disc Ligaments


There are anterior and posterior bilaminar
zones or ligaments, the lateral and medial
collateral ligaments and discomalleolar
ligament. All these are vascular, innervated
and fibro-elastic in nature.




Anterior ligament has a superior stratum that
inserts on ascending slope of articular
eminence and inferior stratums that inverts
inferiorly at the anterior aspect of condyle. The
ligament is normally relaxed and folded on
itself in centric relation. Ligament stretches
downward as condyle rotates during mouth
opening.



Posterior ligament consists of highly elastic
superior stratum that inverts on the lips of
ptetrotympanic fissure and an inferior stratum
that inverts on posterior aspect of condyle
below. It stretches considerably during jaw
opening to allow the disc to continue to cover
condyle at all ranges of motion.




The medial and lateral ligaments are
collagenous and firmly attach the disk to
lateral and medial poles of condyle. These
collateral ligaments allow medio-lateral shift
of the disk during lateral chewing movements.
Traumatic injury to lateral collateral ligament
could lead to subluxation and medial
displacement of disk proper.



It has been reported that posterior bilaminar
zone in joints with anterior disk displacements
without reduction undergo fibrotic changes
and become a disk like structure referred to as
“pseudodisk”. Most medial portion of the disk
is connected posteriorly to a ligament referred
to as discomalleolar or pinto’s ligament which
link between disk and anterior process of
malleus.

FUNCTIONS OF TMJ DISK


Unlike in other synovial joints the TMJ
condyle and temporal bone do not fit together
in absence of disk, Which fills wedge like
gaps created by rounded bony edges of the
joint and thus stabilizes the joint during
rotation and translation


CARTILAGE ASSOCIATED
WITH JOINT


Surface coverings of joint consists of fibro
cartilage rather than fibrous tissue.
Occurrence of such cartilage has a
developmental explanation. A secondary
growth cartilage develops within the blastema
associated with developing
temperomandibular joint  Condylar
cartilage



This cartilage in many ways akin to the
epiphyseal cartilage of developing long bones,
consists of proliferative layer of replicating
cells functioning as progenitor cells supplying
cells to growth cartilage. These cells become
chondroblasts and lay extracellular matrix.
Following this there will be endochondral
ossification



Similar growth cartilage is also found in
association with development of articular
eminence as at birth no eminence is evidenced.


BIO-MECHANICS OF TMJ WITH
RESPECT TO DISC


The superior lateral pterygoid muscle attaches
antero-medially to the disc which keeps the
disc in most anterior position permitted. This
force is opposed by the superior retrodiscal
lamina which pulls the disk posteriorly




Straight line opening and straight line
protrusion produces nearly identical and
bilaterally symmetrical translatory movements
in joints. Deviated or deflected movements
produce compensatory asymmetry of
movement. Lateral excursion produces
maximum asymmetry; the disc-condyle
complex on working side pivots and that of
non-working side translates.





As the forward phase of cycle takes place,
upper surface of articular disc slides down the
eminence, (rounds the crest) and move
forward along its anterior plane. During return
phase of cycle, disc retraces to its position.
Disc rotates posteriorly on condyle as disc
condyle complex moves forward in relation to
eminence. During return phase disc rotates
anteriorly. Greater the inclination of
eminence, greater is the amount of rotation of
disc on condyle.

IMPORTANCE OF DISC
CONTOUR


During opening and closing, disc and condyle
move together, not because of ligamentous
attachment, but because of disc morphology
and interarticular pressure. Because some
degree of interarticular pressure is always
present, Condyle maintains itself on thinnest
intermediate zone of disc.



Thicker anterior and posterior border of disc
force the disc to translate with condyle during
mouth opening and closing. It is disc’s
morphology, there fore that requires it to move
with condyle. Alteration in intra-articular
pressure or change in morphology of disc,
leads to beginning of disc-interference
disorders.



Loss of disc contour destroys it’s self
centering capacity, permitting it to function in
a displaced attitude. Loss of contour
posteriorly permits displacement of disc
anteriorly and loss of contour anteriorly
permits displacement posteriorly in closed
resting position of joint inducing symptoms of
disc interference

DISC
DISPLACEMENT
DISORDERS






Displacement of disc, commonly referred to as
“internal derangement” is a disorder
characterized by abnormal relationship
between disc, condyle and articular eminence.
Disc is most often displaced anteriorly or
anteromedially, but medial, lateral and even
posterior displacements also been reported.
In order for disc displacement to occur, there
must be elongation of disc attachment and
deformation or thinning of borders of disc that
allows the disc to slide in any direction.

CAUSES




When posterior border of disc becomes thinned and
inferior retro-discal lamina and lateral discal
collateral ligament becomes elongated, disc can
assumes a slight anterior and medial position of
condyle
Acute macrotrauma is probably the most common
cause of internal derangement. Among the incidents
described are blow to the jaw, endotracheal
intubation, cervical traction and iatrogenic stretching
of mouth during dental or oral surgical treatment. .





Excessive pressure on joint from clenching,
hard biting or trauma may exhaust the synovial
fluid lubrication between superior surface of
disc and eminence, creating an area of
resistance or adhesion which results in
temporary fixation or adhesion of disc to
eminence where disc remains immobile
‘Frictional inco-ordination’.
Adhesions can occur in superior or inferior
joint spaces.



Temporary adhesion may follow clenching
during sleep. As the patient attempts to move
the mandible a single click is felt, representing
freeing of adhesion and a normal range of
movement is restored. The key in diagnosing
this condition is that the click only occurs one
time and can not be repeated without another
prolonged period a static loading



Temporary adhesions in superior joint space
limit the translation of condyle – disc complex,
thereby limiting the joint movement to only
rotation. Clinically this limits the opening to
only 25 to 30 mm. Adhesion in inferior joint
space restrict rotation of disc on condyle, but
allow translation of disc-condyle complex
leading to normal opening.



It also has been proposed that so called muscle
spasm that occurs in the patients with TMJ
popping or clicking can also cause such
problems. This concept is based on clinical
observations that joint noise in many of these
patients is intermittent and pain generally
arises from masticatory muscles rather than
joint. Such clicking and popping disappears
even though the treatment is directed towards
elimination of myofascial pain and
dysfunction



When posterior discal ligaments are elongated
may be of many reasons like systemic
ligament laxity, the disc can slide anteriorly on
the condyle


DISC DISPLACEMENT WITH
REDUCTION




It refers to the stage in which the disc is
displaced in an anterior or antero-medial
position upon closing and return to more
normal position relative to condyle on opening




History
Joint pain (variable)






Physical examination
Joint tenderness (variable)
Reciprocal clicking
Jaw deviated towards side of click until click
occurs, then returns to midline.
Routine radiographs – not diagnostic

Special diagnostic aids
Condylar path deflection as click occurs
Diagnostic splint ; eliminates symptoms
Arthrogram ; displaced disc that reduces on
opening



If pain accompanies, it generally originates
from strained discal ligaments or from
condylar pressure against posterior attachment,
since they are highly innervated. Mandibular
range of motion is usually normal and in fact
may be more.


DISC
DISPLACEMENT
WITHOUT
REDUCTION
(closed lock)






This condition is characterized by
displacement of disc on closing followed by
failure to reduce or recapture the disc during
translation.
patients who experience repeated dislocations
with reduction may further elongate discal
ligaments. Often elasticity of superior retrodiscal lamina is lost, making it more difficult
for the disc to reestablish normal position on
condyle during opening



change in shape of disc from biconcave to
biconvex and a decrease or loss of tension
in posterior attachment. Contact is lost
between the condyle, disc and articular
eminence and disc space collapses, and
trapping the disc in front of condyle
leading to limited condylar translation 
“Closed lock”.





History
Joint pain (variable)
Limited opening
Previous click with intermittent locking
Joint tenderness (Variable)
Limited opening and lateral movement towards
the opposite side.
Jaw deviation towards affected side.
Terminal stretch produces increased joint pain




Routine radiographs – Not diagnostic
Special diagnostic aids
Arthrogram : Disc displacement and
does not reduces on opening.
Manipulation : May reduce disc


ACUTE STAGE






Restricted opening of maximum of 25 to 30
mm with mandible deflecting towards affected
side. Protrusive excurtion as well as lateral
movement are also restricted.
Generally, acute stage is painful due to
inflamed capsule, posterior attachment and
discal ligaments.
In acute stage, noise is absent, but as it
becomes chronic degenerative changes may
occur in articular surface causing crepitus.

CHRONIC STAGE






Early in stage, mandibular opening may be
slightly limited along with slight deflection
with the time more normal range of motion
returns as posterior attachment and discal
ligaments continue to elongate and perhaps
tear
Pain, if present, is not as severe as in acute
stage.
Most common joint noise is crepitus, which
represents degenerative changes

DISC DISPLACEMENT WITH
INTERMITTENT LOCKING


Same as anterior disc displacement with
education when clicking.
 Same as anterior disc displacement
without reduction when locked.



DISC
DISPLACEMENT
WITH
PERFORATIONS






History
Joint pain (Variable)
Previous history of clicking, clicking
with intermittent locking, and closed lock.
Crepitus
Physical examination :
Joint tenderness (variable)
Crepitus
Limited opening





Routine radiographs ; may show
evidence of degenerative joint disease
but not specifically diagnostic.
A special diagnostic aids : Arthrogram
shows both joint spaces fill
simultaneously


DISPLACEMENT OF DISCCONDYLE COMPLEX


HYPERMOBILITY:


During normal opening, as the disc-condyle complex
translates and moves forward along articular
eminence, disc rotates posteriorly along the condyle.
As a result of excessive opening beyond the normal
limits of translatory cycle, limit of posterior disc
rotation may be reached and any additional opening
will occur without further rotation of disc on condyle.
This can result in rough, noisy movement as disc
condyle complex skid forward as a unit beyond
articular crest. This is “hypermobility” previously
referred as “subluxation



History of wide opening during yawning or
eating

Clinical Features :




Near to end – point of wide opening, there
may be a momentary pause in movement of
condyles after which they jump forward and
upward anterior to the crest of eminence, also
characterized by joint noise “thud”.
Displaced disc can be reduced at any point in
translatory cycle, click associated with disc
reduction

DISLOCATION






Also known as “open lock” is characterized by
inability to close the mouth after wide opening.
Frequently occurs in patients with history of hyper
mobility.
Results from excessive and irregular movement of
disc condyle complex in front of eminence. condyles
may be located too far anterior to the eminence.
In addition, elevator muscle spasm may position
condyle superiorly, preventing it from returning back
over the eminence to its position in glenoid fossa






Some cases of dislocation have been reported
are associated with posterior disc
displacement, preventing its passage over
anterior band. In these cases, the condyle may
not be trapped anterior to eminence.
Pain due to spasm of elevator muscles.
Dippresion in pre auricular region previously
occupied by condyles.

TYPES OF TMJ SOUNDS :




Reciprocal click : Noise made on

opening and closing from centric occlusion
that is reproducible on every opening and
closing and can be eliminated with anterior
repositioning of jaws. Suggests an early
stage disc disorder.


Reproducible opening click : Noise

with every opening, no noise when closing.
Suggests deviation in the form of disc or late
stage disc disorder.



Reproducible closing click : Noise with
every closing, no noise with opening.
Suggests deviation in the form of disc.



Crepitus : Grating noise on opening and
closing suggestive of bone to bone contact
i.e. surface defect on disc or late stage disc
disorder. Cause grating noise suggestive of
osteoarthritis or osteoarthrosis.



POPPING:
Loud sound on opening that is audible to
examiner at a distance without stethoscope.
Suggests early stage disc disorder.



REPRODUCIBLE
LATEROTRUSIVE CLICK :
Noise with every full laterotrusive
movement, no noise on opening.



NON REPRODUCIBLE CLICK:
Not repeatable

Crepitus in the absence of pain may
indicate the presence of “osteoarthrosis” a
non-inflammatory degenerative process
of ariticular tissue that doesnot require
specific therapeutic intervention.
 Only if the sounds are accompanied by
the joint pain, limitation in movement and
joint tenderness, therapeutic intervention
is often indicated



STAGES:


IN INITIAL STAGE OF TM DISORDER :
The opening click reflects the condyle
moving beneath the posterior band of disc
until it snaps into its normal relationship on the
concave surface. Closing click reflects reversal
of this process.




IN PROGRESSIVE STAGE OF TM
DISORDER :
The posterior attachment and collateral
ligaments gradually removed with deposition
of fibrous connective tissue. A single opening
click or fine crepitus can occur as a result of
irregular interferences in translation.



IN THE TERMINAL STAGES OF
TM DISORDER:
Disc perforation and bone to bone contact
will elicit coarse crepitus upon opening and
closing

DIAGNOSIS




The major diagnostic challenge is to
distinguish those patients whose signs and
symptoms are caused by TMJ internal
derangements from those whose disturbances
are caused by muscular disorders
i.e.myofascial pain and dysfunction syndrome,
muscle hyperactivity or bruxism. Furthermore
it must be recognized that internal
derangements and muscular disorders
frequently occurs together.



Diagnosis of TMJ internal derangements is
made through :
History
Radiographs
Special diagnostic procedures


HISTORY


The purpose of history is to furnish clues for
diagnosis. During interview it is important to
assess the patients reliability as a historian.
Are symptoms significant or exaggerated? If
so, patient will tend to exaggerate treatment
effects.Are the problems accurately described
in well-defined terms or is patient vague as to
where and what the problem is? Patients who
clearly describe their problems do better than
patients who are vague.



The history begins with the chief complaint(s).
This should be a statement of patients
reason(s) for seeking consultation and/or
treatment. The patients with internal
derangement’s will generally have a chief
complaint of pain and dysfunction of
masticatory system. Chief compliant often
serves as an important clue with which to
being making a diagnosis



The history of present illness should be
comprehensive, including an accurate
description of patients symptoms, symptom
chronology, how the illness affects the patient,
previous treatments and patients response to
those treatments.


LOCATION OF PAIN


Patients with joint derangements usually
identify the joint area as location of most
severe pain, whereas patients with muscle
disorder describe diffuse areas, often following
muscle distribution. Patients with symptoms
of both will usually describe major component
as worse


DURATION OF PAIN


Generally more acute the problem, more likely
the problem can be managed with simple
therapies, conversely, more chronic the
problem, more difficult will be to resolve.
Patient should be asked when and how the
problems began


CHARACTER OF PAIN


Joint derangements are characterized by
constant pain. The pain may fluctuate in
intensity but generally is present at all times.
Joint pain usually decreases with rest and
therefore would be expected to be less in
mornings. Conversely, joint pain is
aggravated by function and hurts more with
jaw usage



Muscular disorders are characterized by
intermittent pain that may vary in intensity. A
most significant finding is pain that is worse in
morning which indicates nocturnal muscle
activity i.e bruxism. Muscle disorders are
frequently cyclic, with periods of pain free.


JOINT NOISE




Patients with internal derangement almost
always have either clicking and crepitus.
If the patient has clicking, it should be
determined when the jaw clicks. Clicking that
occurs only on awakening is usually related to
nocturnal bruxism, clicking that occurs when
eating may be related to occlusal disharmony








It should be determined whether the click is
painful or not . Patients with internal
derangement frequently experience pain before
the click and decreased pain afterward.
It is important to determine if the noise is
changing which may indicate the presence of
active etiologic factor and progression of
disorder
Crepitus is generally considered to represent
advanced disease.

RANGE OF MOTION




Limited range of motion can be in two forms, limited
opening and limited lateral movement. In anterior
disc displacement with out reduction, patient will
have limited opening (closed lock), Which may be
intermittent or permanent. Patients with intermittent
closed lock usually report that jaw suddenly "catches”
or “get stuck”.
Limited opening because of muscular disorder does
not usually appear suddenly. Patients describe a tight
feeling as opposed to the sensation of jaw being stuck

RELATED DISCOMFORTS


Tooth pain or sore teeth, assuming
odontogenic pathology has been excluded,
indicates bruxism. Patients should be
questioned as to whether or not they grind or
clench their teeth at night or during day.
Many patients will not know, but others will
be aware of his fact. Patient’s awareness
generally indicates high level of bruxism



Retroorbital headaches and earaches including
ear pain, tinnitus and dizziness are the most
common symptom of internal derangement
frequently of affected side


PATIENT CHARACTERISTICS






It is important to determine “how the problem affects
the patient’. Most patients with TMDs report
inability to eat normal diet and some interference
with jaw usage.
Patients should be questioned about stress and
being anxious. Although stress may or may not cause
the problems, certainly it aggravates the problem.
Patient should be observed for signs and
symptoms of “depression”



Other previous treatments such as splints,
occlusal adjustments, physical therapy and
surgery should be carefully assessed as to how
they were done and what their outcome was.
Generally the more treatments a patient has
had, the more difficult the problem is to
manage.


PHYSICAL EXAMINATION


Should evaluate the entire
masticatory system including :
Articular (joint)
Muscular
Dental


ARTICULAR EXAMINATION


Both TMJ should be palpated for the presence
of joint tenderness and they should be palpated
laterally (extra auricular) and through external
auditory canal (intra auricular). Generally
tenderness arising intraarticularly will be
manifested laterally over the joints and also
through the external auditory canal. Although
it will be highly subjective, some estimate of
the degree of tenderness should be made,
characterizing it as mild, moderate or severe.





Mandibular range of motion should be
determined.Normal range is about 50 mm
vertically, 10 mm protrusive and 10 mm
laterally and also normal movements are
straight and symmetric.
In patients with clicking the jaw may deviate
toward the side of click, until click occurs and
then returns towards midline.





Reciprocal clicking is most common in
internal derangements. It refers to click during
closing movement preceded by a click during
opening movement.
The position of opening click is determined
by measuring a vertical opening at the time of
click. As a general rule, later the click, greater
the disc displacement



The position of closing click is being best
determined by having patient protrude the
mandible maximally with the teeth in light
contact, then opens on protruded pathway until
opening click occurs, then to close along
protruded pathway, then mandible is slowly
retruded towards intercuspation while doctor
lightly palpates the angles of mandible. The
position of retrusive click is noted.



The click can be palpated at the angle of
mandible and posterior mandibular teeth shift
slightly upward as click occurs. As a general
rule, closer the retrusive click to the centric
occlusion, better the prognosis of non-surgical
treatment.


MUSCULAR EXAMINATION


Head and neck should be inspected for soft
tissue asymmetry or evidence of muscle
hypertrophy. Patient should be observed for
signs of jaw clenching or other habits. The
muscles should be palpated for presence of
tenderness and spasms


Origin of lateral pterygoid


Insertion of medial pterygoid
(intra orally)


Insertion of medial pterygoid
(extra orally)


Temporalis


Insertion of temporalis


Masseter (extra oral)


Masseter (intra oral)


DIAGNOSTIC IMAGING OF TMD




Before the patients are subjected to the
expense and in most cases, the radiation
of an imaging procedure, a high
probability should exist that the finding
of examination will aid significantly in
the process of diagnosis and will have an
impact on selection of treatment. We
must be concerned with the value of
imaging in term of its usefulness as a
diagnostic test





The accuracy of a diagnostic test is measured
by it’s ability to detect disease when it is
present as well as it’s ability to rule out the
disease when no pathology exists. Sensitivity
and specificity are convenient analysis
techniques that address both of these
measures.
One of the best gold standards for testing
diagnostic accuracy of imaging is fresh
autopsy specimen in which the absence or
presence of disease is verified by direct
observation

Number of specimens correctly
identified as diseased by imaging technique
Sensitivity =
------------------------------------Number of specimens observed to
be diseased by gold standards


Number of specimens correctly identified as
disease free by imaging technique.
Specificity =
-----------------------------------Number of specimens observed to be
disease free by gold standards.




Values range from 0 to 1.0 with 0 representing
total disagreement and 1.0 representing perfect
agreement between gold standards and
diagnostic test.


TRANSCRANIAL
RADIOGRAPHY:





cost effectiveness
Relatively simple head positioning device to
basic dental radiographic equipment allows in
office capability .
High quality views are technically difficult to
obtain because of curved and variable anatomy
of articular component and density of alveolar
structures in surrounding cranial base.

TECHNIQUE


To avoid superimpositions of cranial base and
petrous pyramids of temporal bone onto joint
image, central x-ray beam to be angulated
interiorly in vertical plane at an optimal angle
of 20* which produces profile image of lateral
portion of joint. The central and medial
portion of joint are superimposed onto
condylar neck.



In addition to the required vertical beam
angulation, aligning the central beam with the
long axis of condyle in horizontal plane
minimizes potential for more medial condylar
contour to be superimposed onto joint space.
Errors in horizontal beam alignment as small
as 50 can create this effect and change the
interpretation of condylar position in fossa



Because there is considerable variation in the
condylar long axis angulation between
individual and even from left to right in same
individual, beam angle must be customed for
each patient. This procedure, referred to as the
corrected technique, involves measuring
condylar long axis angulation on a sub-mentovertex radiograph and adjusting condylar
component of head positioning device to
accommodate this angle.



The trans-maxillary projection can be valuable
adjunct to trans cranial view. This coronal
view of condyle’s articulating surface
providing information on central and medial
aspects of the joint that trans-cranial view fails
to supply. This should be taken in maximum
open mouth position to avoid superimposing
the eminence onto articular surface of condyle.

DIAGNOSTIC SIGNIFICANCE


Several studies have questioned the capacity
of trans-cranial radiography to validly depict
joint spatial relationship. Studies have shown
that trans cranial radiography consistently
portrayed the condyles as being posteriorly
positioned whereas actual joint measurement
indicated that the condyels were concentrically
placed

TOMOGRAPHY







Also called as pantomography or rotational
radiography
Improved technology
More expensive and available in only selected
places.
Patient radiation exposure is greater


TECHNIQUE


Uses the principle of controlled motion of Xray beam which blurs most portions of
anatomy in the beam path but leaves the
section of interest less blurred than adjacent
structure. The blurring is produced by moving
the x-ray tube and film in opposite direction




The anatomic section of interest is placed at
the centre of rotation. This section experience
minimal beam movement compared to section
above and below and thus appear in focus.
Image blurring depends on the pattern and
amplitude of x-ray tube movement.






However, dense structure outside plane of
interest such as zygomatic arch, can absorb
radiation and reduce image fidality, refereed as
“superimposition’.
More complex motion patterns such as
circular ellipsoid or hypocycloidal (clover
leaf) minimize superimposition


CORRECTED OR SELECTED
TOMOGRAPHY :




Similar to that used with transcranial technique
involves aligning central X-ray beam with
condylar axis in both horizontal and vertical
plane
The objective is to rotate the head so that long
axis of condyle is either parallel to or right
angle to the film. The obliquity of two
condyles is determined by obtaining a
submento-vertex projection



The following points stress the value of
tomography in evaluation of TMJ :



Relation of condyle to fossa can be studied when this
is narrowed indicates disc damage.
Mobility of condyle may be evaluated by comparing
views taken in closed and open mouth.
Extremely valuable for atypical clinical picture and
for patient who is not responding to treatment in
usual manner.
Valuable in post operative evaluation.
Used in evaluating efficacy of occlusal splints









The following radiologic features
should be observed in tomography :









Shape of head (round, flattened, irregular).
Inclination and length of ramus.
Abnormalities of articular eminence.
Mobility of head in relation to eminence.
Depth of fossa
Position of head in fossa
Width of joint space
Pathology (Tumor, Hypoplasia, Hyperplasia)

TO BE CONTINUED
TOMMOROW


COMPUTED TOMOGRAPHY







The 1979 Nobel prize for medicine was
awarded to “Godfrey Hounsfield” and “Alan
Cormack” for development of CT in 1972
Capacity to provide hard and soft tissue
information from a single examination
Higher cost per examination
High radiation dose .

TECHNOLOGY


It uses multiple thinly collimated X-ray beam
arranged in fan shape to irradiate anatomic
area of interest from multiple directions. The
tint is placed in a circular gantry that has the
source of narrowly collimated beams on one
side aimed at receptor array on the opposite
side. The gantry is rotated sequentially,
passing to irradiate the subject at 2 °increments



Each receptor receives radiation from one of
collimated beams, converts it to an electrical
signal and sends the signal to computer where
it is stored. The signal value or density of any
particular small volume of tissue contributes to
signal received by several different receptors
from many different angulation and allow the
computer to assign an attenuation value for
each small area of tissue.



A single scan or rotation of gantry produces a
thin two dimensional section. A series of
parallel scans adjacent to one another can
produce a three dimensional matrix called
“voxels. By assigning shades of spectrum of
attenuation volumes, multiple planes in
multiple orientations can be constructed. The
sections can be manipulated until the section
that best displays the area of interact is found.





Helical or spiral CT is a variation, the
principle of which is different in that the
patient couch moves continuously during
image acquisition. This movement produces
image data for a portion of spiral rather than
distinct slice.
Electron beams CT differs from other CT
technique in that the gantry acts as anode or
target, a beam of high energy electrons sweeps
continuously around the gantry and produces
X-radiations.

Components :





Gantry : Consists of detector array, and X-ray
source or tube. The gantry can be tilted upto
300 which provides a method by which
structures that may degrade the image can be
excluded from the scan.
X-ray source.
Patient support couch : Provides a way to
stabilize the position of patient during scan





Computer : Rapidity of image capture, data
acquisition and larger matrix size (512 x 512)
necessitates the use of high speed computers.
Modern CT scans require computes that
can solve upto 30,000 equations
simultaneously.
Control console : Which allows the operator to
select the parameters of CT scan, view the
images as they are being generated and
determine format of output



Reconstructed planes perpendicular to the plane of
scanning beams, however have reduced resolution.
This presents problems for viewing the TMJ because
the usual patient orientation in gantry results in axial
plane scanning. In this orientation saggital plane is
perpendicular to scanning plane, wholly required
reconstruction results in somewhat degraded image.
To avoid this problem, patient can be repositioned in
the gantry aligning the sagittal plane parallel to
scanner beam. This is referred to as direct sagittal
CT, the most commonly used technique for TMJ.

CT FOR DISC POSITION







Both sagittally reconstructed view and direct sagittal
scanning technique can be used to identify disc
position.
The direct sagittal technique appears to be best suited
for disc identification. Its’ sensitivity for disc
displacement with reduction is 0.86 and for disc
displacement without reduction is 0.96 with
specificity of 1.0.
CT has good potential to image osseous structure and
position of disc in single examination. Difficulties,
however can be encountered because of similarity in
density of disc and its adjacent soft tissues in
diagnosing disc position

MAGNETIC RESONANCE
IMAGING


It is a conceptually different modality from
previous imaging techniques. Others
including CT, are based on the radiation
absorption characteristics of different tissues.
MRI is based on varying water content in
different tissues and magnetic moment of the
hydrogen atoms or protons within the water
molecule. Major advantage of its complete is
lack of ionizing radiation.

Technology:


Nuclei are composed of varying number of
two types of particles, protons and neutrons
with each of these particles spinning around an
internal axis and developing angular
momentum as a result of this spin. Nucleons
that spin clockwise pair up with nucleons that
spin anticlockwise with their angular
momentum canceling each others.



If there is an odd number of nucleons,
nucleus is left with net angular momentum and
magnetic field because of spinning electrical
charges. In effect, nucleus becomes little bar
magnet.




Although theoretically any nucleus with an
unpaired nucleous could be used for MRI ,
hydrogen is used because of its abundance in
body tissues, primarily in water and fat. The
imaging property of hydrogen vary with type
of molecule with which it is bound




Radiofrequency waves directed to tissue level
induces the protons to align and to process is
phase and an increasing amount of energy is
absorbed. When radiofrequency wave
excitation is stopped, the protons relax to their
original state of minimal excitation and in
process, emit weak radiofrequency waves that
can be detected by a receiver antenna (small
coil placed over the point area in case of TMJ
imaging).

The magnetic dipoles of protons in
water are normally aligned in
random fashion


When they are exposed to strong
magnetic field of MRI scanner,
however their magnetic axes align
parallel with magnetic field.




The signals are location coded as a result of
strength gradation in the primary magnetic
field. This allows the computer to assign an
intensity and location value to the emitted
signals and store the data for eventual retrieval
and manipulation into cross sectional images
at desired tissue depth


SIGNIFICANCE IN DIAGNOSIS
OF DISC POSITION




Sensitivity of 0.86
Specificity of 0.63
Westersson et al attributed this relatively high
false positive rate to the similar MRI
appearance of lateral capsule tissue in normal
joints and discs that are anteriorly displaced
only in lateral position of diseased joint.






Katzberg et al in 1988 did a study on coronal
MRI images of autopsy specimens and found a
sensitivity of 0.87 and specificity of 0.80 for
disc displacements
Cine MRI has been applied recently to
imaging the TMJ which involves making
short, 40 second, low resolution scans at
incremental jaw openings and then fleshing the
scans sequentially on viewing monitor. This
results in cartoon like animation of joint
dynamics

ARTHROGRAPHY:




Norgaard first applied the technique to TMJ in
1940s
Arthrography of TMJ was introduced to
overcome the inability of more conventional
radiographic technique to characterize the soft
tissue in general and position and
configuration of disc in particular






It involves injection of radio opaque contrast
material into joint space. The space occupied
by the disc can then be visualized lying
between layers of contrast material.
Multiple techniques of arthrography have
been used




One approach involves injection of contrast
material into lower joint space referred as
“single contrast orthrography”. Perforations of
disc or posterior attachments are demonstrated
by contrast material simultaneously flowing
into upper joint space as lower space is
injected. Fluoroscopy used with contrast
provides dynamic viewing of disc movements,
disc displacement with reduction can be
directly observed as patient open and closes
TMJ.



Another technique involves injecting contrast
material into both joint spaces and viewing
with tomography. It shows the configuration
and position of disc as contrast material is in
both spaces. It is known as “double contrast
arthrography”


TECHNIQUE :


It should be carried out using sterile
procedures. The superficial and deep tissues
overlying TMJ are anaesthetized with
lidocaine (xylocaine) or mepivacaine,
depending on desired duration of anesthesia.
Then needle is inserted into the joint space,
usually the lower compartment and
intravascular area is anaesthetized.





After verification of needle position in joint
space by fluoroscopy, joint space is filled with
0.5 cc of Water based and low-ionic
concentration iodine containing contrast agent
Then closed, open and protrusive tomographic
images are obtained.


DIAGNOSTIC SIGNIFICANCE IN
DISC POSITION




In double contrast arthrography sensitivity
was found to be 0.95 and specificity 0.84.
Single contrast arthrography had slightly
higher error rates i.e. sensitivity of 0.90 and
specificity of 0.74
Sagittal arthrography appears to be less
capable of assessing the status of disc in
medio-lateral plane





Strength of arthrography is it being the only
technique, in which small disc perforations are
visible and provides accurate information
about disc morphology and position, injection
of contrast agent may tear adhesions results in
improved range of motion and ability to
therapeutic agents like corticosteroids to be
injected into the joint
Weakness includes post-operative discomfort,
morbidity, inability to detect medial disc
displacement, allergic reactions to contrast
agent and post operative infection

Single contrast arthrography


Double contrast arthrography


ARTHROSCOPY
(DIAGNOSTIC)
Dr.Kenji Takagi of University of Tokyo
was the first person to use this procedure
on knee joint in 1918.
 Arthroscopy is nothing but visualization
of potentially expandable, well confined
joints like knee, shoulder or TMJ



Instrumentation


Arthroscope is essentially nothing more
than a long tube with magnification less
at one end, through which a light source
and an irrigating solution are passed. The
ocular piece allows either for direct
visualization or for coupling to a TV
camera. Next to ocular end of
arthroscope is attachment for fiber-optic
light source



The arthroscope is housed within the
cannula which is nothing more than a
sheath of 2.7 to 5.0 mm by which
arthroscope is delivered into joint or by
which irrigating fluid is introduced into
joint. Solution used to irrigate is normal
saline or Ringer lactate. There should be
efflux systems which is nothing but large
needle or cannula through which fluid
drains out of joint

Technique :


Manipulate the mandible anteriorly and
inferiorly. This maneuver allows some
translation of condyle out of fossa and
produces a palpable preauricular
depression. This pre auricular depression
is a critical landmark for joint injection
and arthroscopic entry. Surgeon must
consistently has his left index finger in
depression.



Using 20 gauge needle surgeon then injects the
superior compartment with 1 to 2 ml of 0.5%
lidocaine with 1:200,000 epinephrine. This is
done for operative haemostasis and postoperative analgesia. Angulation of needle
puncture is from infero-lateral- posterior
approach so that needle tip is aimed at
posterior slope of articular eminence. Next 3
to 4 ml of Ringer lactate solution is injected
into superior compartment. A back flow of
fluid is seen which confirms that superior
compartment iswww.indiandentalacademy.com
adequately filled.

As soon as lateral TM capsule is
punctured, the sharp trochar is replaced
with blunt obturator which can be used as
a probe, fossa and eminence are gently
and carefully manipulated for tactile
orientation
 Out flow is established by creating
another portal approximately 3 to 5 mm
anterior to original portal for which an
outflow needle or trocher with sheath is
used for puncture





Finally blunt obturator is removed from
the sheath and 1.9 mm orthroscope with
attached camera head is inserted. The
inflow tubing is then attached to the
sheath once inflow and outflow of
irrigant have been established
orthroscopic examination of TMJ may
proceed

It provides a narrow, continuous image of
surface morphology. Disc displacements
were correctly diagnosed in five out of
six joints
 Perforations were correctly diagnosed in
two out of three joints. It provides most
information about location and size of
perforation and associated pathological
changes



TREATMENT FOR
INTERNAL DERANGEMENTS






Successful management of disc-interference
disorder is also based on the natural course of
disease. In which stage of progressive
description of disc interference disorder should
be considered
Epidemic studies reveal that a symptomatic
joint sounds are common and all joint sounds
are not progressive. Then which should be
treated? In Jeffrey P.Okeson’s opinion only
joint sounds associated with pain of
intracapsular origin should be considered for
treatment



Treatment can be divided into non-surgical
and surgical methods. Presently treatment is
largely based on theoretic concepts and
empirical clinical observations


NON-SURGICAL MODE




It involves the use of bite appliance that
positions the mandible slightly vertically
open and anteriorly to maintenance disc
in normal relation to the condyle. The
position of retrusive click is used to
determine the probability of successful
non-surgical therapy. Closer the retrusive
click to the intercuspal position, better
the prognosis.





Maxillary or mandibular appliances can be
used, patient must wear the appliance for 24
hours.
Intraocclusal registration is taken at the
position of the mandible at which discs are
reduced. Especially important are the
inclinations to intercuspal contacts that
maintain the anterior position of mandible
during function





After one month, patient should be re-evaluated for
symptoms. An increased range of motion without
clicking should be noted. Then necessary provision
should be made to allow condyle to move closure to
original hinge position. This adjustment of splint is
continued monthly until the condyle is back to the
hinge position. The patient should be maintained in
position for approximately two months to allow
stabilization of joint structures.
Evaluation of occlusion is final position without
splint is needed to plan the next phase of treatment
i.e. occlusal adjustment, restorative treatment or
orthodontics or all three

TREATMENT FOR DISC
DISPLACEMENT WITH
REDUCTION




Treatment with anterior positioning splint suits
this condition much.
Studies concluded that anterior
repositioning appliance therapy followed by
stepping the condyle back to original occlusal
position failed to recapture the disc. Only
25% to 36% of patients were found to be free
of both pain and joint sounds





Another feature that complicated this therapy
was that some patients developed posterior
open bite
Failure to recapture the disc and possibility of
posterior open bite demonstrated that these
appliance were not as successful as first
believed. During initial weeks of therapy,
anterior repositioning appliances were more
successful in reducing pain and dysfunction





In many patients advancing the mandible
forward for a period of time prevents condyle
from articulating with highly vascular and
innervated retrodiscal tissues, Which leads to
immediate reduction of intracapsular pain.
It is now understood that disc does not return
to the condyle, instead condyle moves
posteriorly to articulate with adaptive
retordiscal tissues

DISC DISPLACEMENT
WITHOUT REDUCTION





Placement of anterior repositioning appliances
in this situation only aggravates the condition
as forward positioning of condyle pushes the
disc more anteriorly and medially.
Many clinicians agree that re-establishing
normal disc position can often be
accomplished by manual manipulation
technique. The successfulness of which
depends on factors like acuteness of disease
(more than a month bad prognosis) and age
and post history of patient





Because manual manipulation is a
conservative and relatively benign procedure,
attempts are recommended in all patients
diagnosed with disc displacement. If disc is
successfully reduced an anterior repositioning
appliance is immediately inserted and protocol
for disc dislocation with reduction should be
followed.
When manual manipulation fails to reduce the
disc, surgical intervention is the method of
choice

ADHESIONS :




There are generally resistant to non-surgical
management.
The exception is early sticking secondary to
static loading. In such cases, treatment should
not be directed towards adhesion itself, but
towards controlling static loading may be due
to parafunctional habits like clenching or
bruxism with patient education, behavioral
control of habits and stabilization appliance
during sleep

ALTERATIONS IN FORM


The definitive treatment for both adhesions
and alterations in form is often surgical
intervention. Because surgical procedures
have inherent risks, the degree of pain and
dysfunction should be ascertained before
surgical repair is considered


MANUAL MANIPULATION




The success of manual manipulation depends
on three factors.
First is the level of activity in superior lateral
pterygoid muscle. This muscle must be
relaxed to permit successful reduction. If it
remains active because of pain or dysfunction,
it should be injected with local anaesthetic
solution.





Second disc space must be increased so that
disc can be reduced. The patient needs to be
relaxed and close the mouth, as increased
activity of elevator muscle increases
interarticular pressure, making it more difficult
to reduce the disc
Third factor is that condyle must be in
maximum forward translatory position. The
only structure that can actively reduce the
anterior dislocation of disc is retrodiscal
lamina, for which the condyles must be in
forward most position.



Definitive treatment begins by having the
patient attempt to reduce the dislocation
without assistance. The patient is asked to
move the mandible to contra lateral side as for
as possible. From this eccentric position the
mouth is opened maximally. If this is not
successful at first time, should attempt this
several times



Thumb is placed over the mandibular molar
intra-orally, on affected side. Fingers are
placed on inferior border of mandible anterior
to thumb position. Firm but controlled
downward force is exerted on the molar at the
same time upward force is placed by the
fingers. The opposite hand helps to stabilize
the cranium above the joint that is being
distracted , the condyle is brought downward
and forward, which translates it out of the
fossa.



Once the full range of laterotrusive excursion
has been reached, patients asked to relax while
20-30 seconds of constant destructive force is
applied to the joint. This force is then
discontinued and patient lightly closes to
incisal edge to edge position. After relaxing
for few seconds open widely and returns to
this anterior position (not maximum
intercuspation). If the disc has been
successfully reduced, an anterior repositioning
appliance is immediately placed and thus
managed as same as for dislocation with
reduction

SURGICAL MODE


Indications


Patients with pain and clicking whose
pain does not respond satisfactorily to
non-surgical therapy over a period of
three months are candidates for surgical
therapy, provided that pain is intracapsular and not myo-fascial in origin


Arthrocentesis
Simple and efficient procedure that can
be performed under local anesthesia
 Procedure in which the fluid in joint
cavity is aspirated with the needle and
therapeutic substance is then injected.
 Owing to it’s simplicity, it may be
performed repeatedly







A line is drawn from middle of tragus to the
outer canthus of eye. Posterior entrance is
located along cantho-tragal line, 10 mm from
middle of tragus and 2 mm below. Anterior
entrance is placed 10 mm further forward and
10 mm below it. These indicates location of
articular fossa and eminence respectively.
A local anesthetic is injected at the planned
entrance points avoiding penetration into the
joints. A 19 gauge needle is inserted into
superior compartment and lactated Ringer
solution is injected and immediately aspirated.
The procedure is repeated three times to obtain
sufficient amount for diagnostic purpose





Another 19 gauge needle is inserted into
distended compartment in the area of articular
eminence to enable free flow of solution. Like
this approximately 200 ml solution is passed
through joint space. On termination, a steroid
solution is injected and needles are removed.
The negative pressure measured in upper
compartment is eliminated by introduction of
needle into the compartment. It also loosens
the adhered disc, reinstitutes it’s free sliding
moment, removes inflammatory constituents
and pain mediators there by bringing about
recovery of intra-articular pressure fluctuation.

ARTHROSCOPY


Arthroscopy has the obvious advantage of
visualization of the joint for a more complete
diagnosis which provides information abut
disc-position and morphology, status of
articular surface, presence of adhesions that
arthrocentesis cannot. Otherwise therapeutic
goals of arthroscopy and orthocentesis are
similar

DISC REPOSITION SURGERY


Through a pre-auricular incision, a
partial thickness plication was performed.
Recontouring of articular eminence was
performed in the areas of bony
irregularities or impingement, if the disc
position was satisfactory with teeth in
occlusion and during manual jaw
movement, surgical site was closed in
layers. Movement of TMJ was instituted
immediately after surgery

CONDYLOTOMY



Oral vertical ramus osteotomy
The bone is cut and inferior 50 to 60% of
medial pterygoid muscle is detached from
proximal segment to permit anterior and
inferior displacement of condyle.


DISCECTOMY (AND
REHABILITATION
Only disc should be removed to
maximize retention of synovial surface
for secretion of synovial fluid. Small
osteophytes and adhesions should be
removed
 Proper rehabilitation is extremely
important for a good result





The various interpositional grafts are ;
Auricular cartilage
Dermal grafts
Temporal fascia-muscle – pericranial
grafts
Alloplastic implant materials like
Teflon-Proplast, Silicon, Silastic etc.
Metal implants like stainless steel
fossa and vitalium glenoid fossa, cobaltchromium molybdemus

IT’S RELATION TO
ORTHODONTICS


TMD AND ORTHODONTIC
ISSUES




Improper orthodontics can be contributory to
TMD, if not causalgic. Orthodontics should be
TMD neutral or lessening severity of it’s
influences
Lack of screening or attention to TM disorder,
orthodontist may be incriminated for having
caused these problems. Such disorders are
typically evident or subclinical prior to
commencing with orthodontics, unless
documented or effectively managed, chances
to misinterpret post treatment signs and
symptoms to have been result of orthodontics

Contributing factors











Inappropriate diagnosis and treatment plan.
Lack of differential diagnosis and treatment
for skeletal components underlying the
malocclusion.
Inadequate attention to detailing and
finishing.
Lack of attention to the neuro-muscular
aspect.
Related systemic, endocrine illness
Parafunctional habits which go unmanaged.
TMJ loading incompatibilities

WARNING SIGNALS BEFORE OR
DURING ORTHODONTIC
TREATMENT








Pain
Limited and/or irregular mandibular
movements
Cripitius, clicking
Loose ligaments
Cuspal interferences with braces or wires
Elastics and chin cup therapy : Unfavorable
TMJ loading and compression













Lingually tipped uppers entrapping the
mandible.
Not treating or recognizing skeletal problems
with facial orthopedics or orthognathic
surgery when appropriate.
Lack of transverse up righting of arches
(Curve of Wilson).
Vertical collapse.
Loss of posterior support due to : missing
teeth, inadequate eruption, attrition.
Clenching / grinding pattern.
Oversized splint which violates freeway
space

OCCLUSAL INTERFERENCES
AND TMD


occlusal interferences that cause extreme
subluxation of condyles in lateral extrusion
and /or protrusive and /or closure to maximum
interdigitation, twisting and torquing of
mandible during centric closure results in
stretching of musculature which leads to
increased muscle tension thus making
individual predisposed towards developing
pain – dysfunction symptoms.

Protrusive interferences of molars in the
form of missing ,drifted and
supraeruption are the most damaging of
all types.
 Protrusive interferences of anterior teeth
in the form of malpositioned in the arch
or anterior crossbite





Non-working interferences or balancing
interferences are probably more
damaging than working interferences.
The non working condyle is moving
condyle has a wider range of movements
during lateral excursion and more
vulnerable to forces generated by
deflective occlusion

Orthodontic reasoning for these
interferences are ;








Failure to achieve true antero-posterior
correction of jaw relation.
Insufficient lingual crown torque of maxillary
first and second molar.
Too much lingual crown torque of mandibular
molars.
In co-ordination of arch widths and arch form

MALOCCLUSION AND TMD


Most of the studies says no co-relation
between Angle’s Classification and TMD.
Class II Division I malocclusion
Class III
Anterior open bite, Crowding, spacing,
tipping and rotation
Incisor and buccal crossbite,

Class II Div. I
To improve their profiles, often position the
mandible forwards, moving the condyles
forward on articular eminence. The muscle
and ligaments may be overstressed and
fatigued. These individuals do not normally
have disclusion on anterior teeth during
protrusive movements

Class II Div. II
Often have “locked” anterior bite due to
excessive vertical overlap of anteriors which
can cause the condyles to be deflected
posteriorly and distally which can produce
trauma to retrodiscal tissues. These also have
limited range of mandibular function. These
individuals have excessive anterior disclusion.





Class III :
These lack anterior disclusion, especially
during protrusive movements when the
canines are not properly positioned.
Open bite :
In cases of both anterior and posterior open
bites, individual may exhibit gross occlusal
interferences on posterior teeth.



Posterior bite Collapse :
This can be due to tilted, drifted and/or
rotated posteriors. When posteriors that
normally act as posterior stops are absent
individual often presents with condyles
displaced distally and superiorly till anteriors
becomes stop


ORTHODONTIC
TREATMENT AND TMD


Initially, in Costen’s syndrome, it was
common to identify TMD by the perceived
etiology of deep bite. Lack of posterior
support by the dentition was thought to be an
integral part of the syndrome itself. Thus it
was no surprise to find abundant literature on
relation between jaw dysfunction and
malocclusion



However, it is difficult to understand why
correction of malocclusion through
orthodontic treatment was suddenly received
full blame. Supposed etiology, such as
orthodontic treatment, was mentioned though
not proven to be associated with TMD. The
condyle disc assembly was assumed to be
displaced, through orthodontic intervention
which was supposedly caused dysfunction


FUNCTIONAL APPLIANCES AND
TMD


Ample of excellent clinical studies especially
of European origin were done to inquire about
relation between TMD and functional
orthodontics. These concluded that functional
appliances were never related to TMD and
long term study failed to find different
prevalence between treated and untreated
individuals. Some authors concluded that
dysfunction was consistently less prevalent in
treated than reference population.

FIXED APPLIANCE AND TMD


Studies on fixed appliance (Edgewise as well
as Begg) and TMD report consistently
concluded that : fixed appliance treatment and
dysfunction are not related, such a conclusion
is reached after many, research protocols


A longitudinal study
Orthodontics and TMD


In January 1970, a longitudinal and
prospective study began in Groningen,
Netherlands with the aim of monitoring any
development of TMD in a group of children
receiving orthodontic treatment.




In 1972, 172 children were documented with an
average age of 12.5 years. They were documented
before starting their treatment, annually from the start
of treatment through at least one year out of retention,
followed by an interval of five year without retention.
Follow ups were then performed in1980, 85 and 90.
Orthodontic treatment consisted of all three
categories of removable appliances, mostly
functional; Begg Class I and II fixed appliance; chin
cup and/or Begg Class III treatment. About one third
treated with extraction of all four first premolars, one
third non – extraction and remaining combination of
extraction

Three totally different treatment modalities,
relying upon different bio-mechanics with
different reaction forces within joint, should
generate different frequencies after treatment,
if at all ortho treatment was truly considered
harmful.
At the end, they concluded that no
relationship between TMD and orthodontics
could be substantiated

Extraction Therapy and TMD


Studies to investigate the relation between
TMD and extraction approaches, compared all
first bicuspid, other extraction and nonextraction groups and observed that cases with
all four first bicuspid extraction seemed worse
in the long run.


Gianelly et al (AJO, 1988) reasoned
and questioned whether a result of
extraction may be the reclining of upper
front teeth inward, forcing condyles
backward in fossa
Evidence in the literature,
unequivocally points to no relationship
between orthodontic treatment and
symptoms of dysfunction.

ORTHOGNATHIC SURGERY
AND TMD


Anders westermark et al (Int J Adult Ortho and
Orthognathic Surgery) conducted a study on
1516 patients undergone orthognathic surgery,
evaluted 2 years after surgery found that preoperatively 43% and post-operatively 28%of
patients reported symptoms of TMDs, which
indicates an overall beneficial effect of surgery
probably a result of improved occlusion.





In the study mandibular retrognathia was less
favorable result than prognathia.
Sagittal ramus osteotomy was less effective
than vertical ramus osteotomy


Maintenance of inter condylar width,
angle and position are major concern
during mandibular procedure


MANAGEMENT OF INTRA AND
POST-ORTHODONTIC TMD
PROBLEMS


Most of the problems arise during orthodontic
treatment do not require any specific
procedure to be initiated, but if painful
symptoms arrive during treatment, it may be
necessary to modify the active therapy : for
example reduce forces on extra oral head gear,
eliminate direct mandibular distalizing force
(chin cup) and remove or lighten class II
elastics, eliminate gross occlusal interference
generally will allow sore joint to recover
enough.



Elimination of TMJ clicking is not
desirable or possible as a part of
orthodontic therapy. However if desired
maxillo-mandibular relationship is one
that also reduces a displaced disc for
example advancing class II mandible and
opening it to reduce deep bite, then it can
be incorporated into orthopeadic or
orthodontic treatment plan



It is not common, for TMD symptoms to
arise during or shortly after the retention
phase of treatment. When they do occur,
the orthodontist should re-evaluate both
retention appliance and the final
occlusion


REVIEW OF LITERATURE ON
RELATION BETWEEN TMD AND
ORTHODONTICS




Erik Larsson and Assar Ronnerman (EJO,
1981) concluded that extensive orthodontic
treatment can be carried out without fear of
TMD and no over representation of symptoms
in patients in whom sagittal and vertical
movement of teeth was especially great. But
special attention should be paid to torque the
molar during treatment or during expansion of
upper jaw. If they arrive should be eliminated
by grinding.
Ortho treatment prevents, rather causes
TMDs



Michael Johnson and Asbjorn Hasuud (EJO,
1981) says orthodontically treated cases
presents less functional problems than
untreated malocclusion.
In patients with Class II Division I who can
be treated without extraction, early ortho
treatment can be regarded as prophylactic
treatment.
Cases treated without extraction showed
significantly less clinical disturbances than
both extraction and control group.



G.Madone and B.Ingervall (EJO, 1984) found
that signs and symptoms in group of patients
who had undergone activator treatment
conform prevalence in untreated series. It is
possible that subjects in this series if left
untreated would have more signs and
symptoms




Frank E.Cordray (Quintessence 2002)
considers establishing functional occlusion and
seated condylar position as one of the goal of
orthodontic treatment.
For that he suggests that discrepancy
between seated and unseated condylar position
should be identified and eliminated when
occlusion is re-organized. Identification of
this discrepancy through the use of diagnostic
cast that has been taken from unprogrammed
patient and mounted in seated condylar
position on a semi-adjustable articulator
through estimated face bow transfer.



Sabine Ruf, Hans Pancherz (AO, 2000)
concluded that bite jumping with Herbst did
not result in any muscular TMD, rather
reduced the prevalence of capsulitis, did not
induced disc displacement in subject with
normal pre treatment disc position, resulted in
stable repositioning of disc in subjects with
partial disc displacement with reduction, but
could not re capture the disc in subject with
total disk displacement with or without
reduction.
However disc displacement does not seem
to be contraindication for Herbst treatment



Dibbets and Van der Weele (AJO, 1991)
concluded that neither removable nor Begg
mechanics are associated with TMD, except
for therapy that involves all first bicuspid
extraction with which there was segregation of
higher frequency of objectively identified
clicking which the study could not reveal
weather was due to extraction or because of
sampling effect




O.Reilly et al (AJO, 1993) did a study to find
relation between TMD and orthodontic
treatment with straight wire mechanotherapy
along with extraction and Class II elastics and
concluded that mechanotherapy has no effect
on TMJ except for pain on palpation lateral to
TMJ capsule which was observed in 40% of
study sample for which there is no logical
explanation



Gianelly et al (AJO, 1988 and1989) conducted
a study to evaluate two hypothesis. One
particulates that condylar position in patients
treated with four premolar extraction would be
more posterior. Second, condylar position in
patients with deep bite would be more
posterior. He concluded that neither of these
hypothesis are associated with posterior
positioning of condyle



Dr.H.P.Bimler (Functional Orthodontist, 2000)
says that modern fixed appliance methods start
routinely by flattening the curve of spee which
definitely disturbs the physiological path of
mandibular movement which can be
suspectable reason for grouping number of
TMJ problmes.
Free floating loose appliance, leave the
teeth free to arrange themselves into an
optimalposition with regards skeletal as ell as
functional matrices of stomatognathic system

Dr.Grant R.N.Bowbeer (Funct. Ortho. 1993) has










given seven keys for facial beauty and TMJ health :
Proper maxillary A-P position
Proper maxillary arch width and form
Proper vertical dimension (Lower face height)
Proper mandibular A-P position in relation to
properly located maxilla.
Mandibular symmetry (mandibular skeletal midline
aligned to maxilla).
Proper uprighting of lower posterior and arch from.
Proper condylar position i.e. seated properly in fossae



McNamra (OOO, 1997) concluded that the
signs and symptoms of TMD increases with
age, particularly during adolescence and
therefore TMDs that originate during
orthodontic treatment may not be related to
treatment
Ortho treatment performed during
adolescence does not increase or decrease the
chances of developing TMD in later time


The extraction of teeth as a part of
orthodontic treatment doesnot increase the risk
of TMD nor the mechanics is associated
Although stable occlusion is the goal, not
achieving a specific gnathological ideal
occlusion does not result in TMD and also
there is little evidence that orthodontic
treatment prevents TMD.





Reint M.Reynders (AJO, 1990) in his review
of literature from 1966-1988 on orthodontics
and TMD (88 articles) concluded that
orthodontic treatment should not be considered
responsible for TMD. He also rejects that
ortho treatment is specific or necessary to cure
TMD.
Luther (AO, 1998) in his review article says
that ortho treatment has nothing to do with
inducing or curing TMD





Klans et al (EJO, 1991) conducted a study that
failed to reveal ortho treatment as frequent
cause of stomatognathic dysfunction
symptoms
John Artun et al (AJO, 1992) says that it can
not be ruled out that some patients acquire
more posterior location of condyles during
correction of Class II Division I malocclusion
with extraction of maxillary premolars.
However prevalence of patients with definite
posterior displacement of condyles or joint
sounds shortly after therapy in similar to that
seem in controls





Martin Olsson and Berit Lindquist (EJO,
1995) reveals that orthodontic treatment can to
some extent prevent further development of
and cure TMD
J.M.H. Dibbets and L.Th.Van Der Weels
(AJO, 1987) conducted a study of 10 year old
long term post orthodontic treatment cases
(Begg and Activator) and concluded that
registration of symptoms during ortho
treatment should be attributed to age changes
rather to treatment procedures



In patients with TMJ dysfunction, proper
sequence of treatment is ;
Correct the TMJ
disfunction- repositioning splint
Correct skeletal
problem- orthopedic appliance
Correct the dentition- fixed
appliance Replace missing teeth- prosthesis





Dr. Timothy J.Flacherty (Funct Ortho 1994)
has the opinion that Jaw repositining in the
vertical and antero-posterior dimensisn is an
accepted and effective technique for relief of
TMD weather it be maloclcusion, trauma or
airway induced
Dr. James M. Broadbent (Funct Orhto 1994)
says that functinal jaw orhtopedics is an
important mehod of correcitonof certain
malocclusion and TMJ disorders



Dr.Terrance J.Spahl (First Ortho 1996) says
that extraction of bicuspids does not cause
“TMJ” disroder. It does not matter of where
the disc or condyle resides at full oclcusion,
it’s matter of where the condyle resides
comfortably at full oclcusion that is the real
key.




Dr. Duane C.Keller (Fuset Ortho 1996) says
that “orthodonics plays an important role as
both cause and a treatment for TMD.
Treatment for internal derangemnets
necessitates correction of abnormal condylar
position before the disc can be properly
positioned.
One of the problem with conventional
orhtodonics involves lack of contorl over
condylar positoin

CONCLUSION


In evaluating the orthodontic
literature and treatment as it regards
TMD’s, perhaps the state of issue can
be best described as “It ain’t so

much that get’s us in trouble. It’s
the things we know that ain’t so”.



Orthodontic movement of teeth and
incidence of TMDs are associated
just like every other aspect of
rehabilitative dentistry is related to
the joint around which oral structures
function



Attempting to avoid the issue,
claiming “no-reposibility”,
presenting skewed or distorted
material which does not follow
accepted or valid scientific methods
and presenting just one side of
issue,borders an inappropriate
professional action and substantiates
a need for professional dialogue.

BIBLIOGRAPHY












Temperomandibular joint and masticatory muscle
disorders. George A.Zarb, Barry J.Sessle, Gunnar
E.Carlson, Norman D.Mohl.
Temperomandibular disorder, classification,
diagnosis and management – Welden E.Bell.
Clinical Management of Tempero-mandibular
disorders and oro-fascial pain. – Richard A.Perter,
Sheldon G.Gross.
Occlusal correction – Principles and Practice –
Albert Solnis, Donald C.Curntte.
Diseases of Tempero-Mandibular Apparatus. –
Douglas H.Morgan.
TMJ, Internal Derangement and Arthrosis –
M.F.Dolwick, B.Sanders.













Temperomandibular disorders and oro-facial pain.
DCNA, Jan 1991.
TMJ Dysfunction and Treatment – DCNA, July
1983.
Current controversies in Surgery for Internal
Derangements of TMJ. – O.M.F.S.C.N.A., May
1994.
Adult Orthodontics – D.C.N.A.
Maxillofacial Imaging, Principles and Application.
O.M.F.S.C.N.A. Nov 2001.
Oral Radiology – Goaz and White.
Tempero-Mandibular Disorders – Fonseca, 4th
Volume







Diagnostic and Surgical Arthroscopy of TMJ
– Sanders, Marakoni and Clark.
Fundamentals of Occlusion and Temperomandibular disorders – Jeffrey P.Okeson.
Gray’s Anatomy – Peter L.Williams


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