Temporo mandibular joint /certified fixed orthodontic courses by Indian dental academy

TEMPORO MANDIBULAR
DISORDERS
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com


 Terminology
 Functional Anatomy And Biomechanics Of Masticatory
System
 Etiology of Temporomandibular Disorders
 Orthodontic Concepts of TMD Etiology
 Radiographic Diagnosis of Temporomandibular Disorders
 Classification of TMD’s
 Clinical diagnosis and Management
 Conclusion

Terminology


• Costens syndrome
• Shore – 1959- TM J dysfunction syndrome
• Ramfjord and Ash – Functional TMJ Disturbances
• Occluso-mandibular disturbance
• Myoarthropathy of TMJ
• Pain dysfunction syndrome / MPDS / Temporo mandibular pain
dysfunction syndrome.
• Craniomandibular disorders
• Bell –Temporomandibular disorders( ADA )


• Dr. James Costen – 1934 suggested that changes in dental
condition is responsible for various ear symptoms.
• Suggested treatment using bite raising appliance.
• 1950’s –
• Early scientific studies suggested that occlusal condition could
influence masticatory muscle function
• Masticatory Muscle Pain
• Etiologies- occlusal disharmony and emotional stress
• 1970’s – Intracapsular Sources


Functional Anatomy And Biomechanics Of
Masticatory System


• The masticatory system is a complex and highly refined unit
composed of
• Dentition and supportive structures
• The skeletal components
• TMJ
• Muscles and ligaments.


TMJ
• Anatomy of TMJ
• Ginglymo - arthroidal joint
• Compound joint
• Synovial joint
• Exchange of metabolites
• Lubrication
• Boundary lubrication – primary mechanism for joint
lubrication while movement
• Weeping lubrication – eliminated friction In
compressed joint.


Condyle

Temporal bone


Articular disc
•
•
•
•

Composed of dense fibrous
tissue
Avascular and non
innervated
Flexible and adapt to
functional demands
Attachments


Functional LigamentsCapsular ligament

Temporomandibular ligament

Collateral (discal) ligaments


Accessory Ligaments Sphenomandibular ligament

Stylomandibular ligament


Muscles of mastication
•
•
•
•

Masseter
Medial pterygoid
Temporalis
Lateral pterygoid

Jaw movements
 Depression –
 Lateral Pterygoid complemented by Geniohyoid ,
Mylohyoid & Digastrics.
 Elevation –
 Temporalis , Masseter & Medial Pterygoid.
 Protrusion –
 LPM & Medial Pterygoid.
 Retrusion –
 Posterior Fibers Of Temporalis, assisted By Middle & Deep
Parts Of Masseter, Digastric & Geniohyoid.

BIOMECHANICS OF TMJ
• TMJ is complex joint system.
• 2 joints act independently and simultaneously.
• 2 joint systems are present
• Tissues surrounding inferior joint cavity( condyle disc
complex)
• Responsible for rotation movement
• Tissues surrounding superior joint cavity
• Responsible for gliding movements
• The disc functions ars true articular surfaces in both joint
systems

• Stability of joint is maintained by constant activity of muscle that
pull of muscles that pull across the joints-elevators
• Tonus- mild state of contraction of muscles in the resting state.
•
•
•
•

Interarticular pressure
Closed rest position- low pressure - disc space widens
Clenching- high pressure disc space narrows.
Increase in the interarticular pressure– condyle seats on thinner
intermediate zone of disc.
• Decrease in pressure – disc space widens


• Ligaments do not actively participate in functions of TMJ
They restrict certain joint movements while allowing others
mechanically and through neuromuscular reflex.

• Ligaments do not stretch
Once elongated, joint function is compromised

• Articular surfaces must be maintained in constant contact.


Etiology of Temporomandibular Disorders


• No single etiology to explain all signs and symptoms
disturbances in masticatory system.
• TMD symptoms arise
• Normal function + event> physiologic tolerance

Symptoms


• Normal function :
• Chewing, speaking, swallowing.
• Brain regulates muscle action by means of muscle engrams that
are appropriately selected according to sensory input received
from peripheral structures.
• When sudden sensory input is received, protective reflex
mechanisms are activated ,creating a decrease in muscle
activity in that area.


• Event
• Local events
• Any change in sensory or proprioceptive input – highly
placed restoration
• May be secondary to trauma involving local tissues –
injection of local anesthetic, mouth opening too wide,
unaccustomed use – bruxism
• Constant deep pain input - central excitatory effects –
referred pain


• Systemic events
• Emotional stress
• Stress centers in brain have influence on muscle functionincrease muscle tonicity.
• Stress defined by Hans Selye as ‘non specific response of
the body to any demand made upon it’
• Circumstances creating stress are called ‘stressors’
• The body reacts to stressors by creating demands for
readjustment or adaptation – fight / flight response
• Two types of releasing stress
• External mechanism – shouting ,hitting, physical
exercise, etc.
• Internal – gastritis, hypertension, increase in tonicity of
musculature.


• Physiologic tolerance :
• Is influenced by local and systemic factors

• Local factors :
• Orthopedic stability – when mandible closes with condyles in
most supero-anterior position, resting against the posterior
slopes of articular eminence, with disc properly interposed,
there is even and simultaneous contact of all teeth, forces
directed towards long axis of teeth, from that position when
mandible moves eccentrically – anterior teeth contact and
disocclude posterior teeth.


• Effected by genetic ,developmental or iatrogenic causes, disc
displacements, arthritis.
• Lack of harmony between state intercuspal position of teeth
and musculoskeletally stable position of joint.

• Systemic factors :
• Constitutional factors
• Presence of other acute/chronic illness
• Sympathetic activity


• TMD symptoms:
•
•
•
•
•
•
•

Pulptits
Tooth wear
Tooth mobility
Masticatory muscle pain
TMJ pain
Ear pain
Headache


• 1. Predisposing factors : include a mixture of morphological,
physiological, psychological, and environmental variables that
heighten an individual's susceptibility to develop a certain
problem.
• 2. Precipitating factors :include various combinations of trauma,
stress, hyperfunction, and possibly failure of natural inhibiting
factors, all of which lead to the onset of symptoms.
• 3. Perpetuating factors :include poor healing capacity, failure to
control etiologic factors, secondary gains from staying sick, and
negative effects from inappropriate treatment.


• Primary vs secondary disorder
Disc derangement disorders

Masticatory muscle disorder

Trauma

Inflammatory disorders

Mandibular hypomobility disorders


Orthodontic Concepts of TMD Etiology
• Thompson believed that most condyles needed to be brought
downward and forward -"freeing up a distalized (trapped)
mandible,“
• Ricketts , Perry, Jarabak,and Moyers
• Orthodontists began attributing TM disorders to improper
finishing of orthodontic cases and a lack of appreciation for
"correct" concepts of functional occlusion


• Despite considerable debate about this subject, it never was
shown scientifically that any "wrong" concepts of occlusion or
"improper" finishing by orthodontists using diverse methods had
produced any significant number of post orthodontic TMD
sufferers.
• Any Superior methods of finishing cases ???????


"Orthodontics and Temporomandibular Disorders" - Dent Clin North

Am 1988;32:529-538
•

a list of 10 myths in the field

1. People with certain types of untreated malocclusion (for
example, Class II Division 2, deep overbite, crossbite) are more
likely to develop TM disorders.
2. People with excessive incisal guidance, or people totally lacking
incisal guidance (open bite), are more likely to develop TM
disorders.
3. People with gross maxillomandibular disharmonies are more
likely to develop TM disorders.

.


4.

Pretreatment radiographs of both TMJs should be taken
before starting orthodontic treatment. The position of each
condyle in its fossa should be assessed as good or bad, and
orthodontic treatment should be directed at producing a good
relationship at the end. ("Good" position usually was defined
as being a concentric placement of the condyle in the fossa).

5.

Orthodontic treatment, when properly done, reduces the
likelihood of subsequently developing TM disorders.

6.

Finishing orthodontic cases according tospecific functional
occlusion guidelines (eg, gnathologic principles) reduces the
likelihood of subsequently developing TM disorders.


7. The use of certain traditional orthodontic procedures and/or
appliances may increase the likelihood of subsequently developing
TM disorders.
8. Adult patients who have some type of occlusal "disharmony" along
with the presence of TMD symptoms will probably require some
form of occlusal correction to get well and stay well.
9. Retrusion of the mandible because of natural causes or after
treatment procedures is a major factor in the etiology of TM
disorders.
10. When the mandible is distalized, the articular disc may slip off the
front of the condyle.


•

NIDR -McNamara, Seligman, and Okeson listed eight
conclusions that essentially refute all of the previous
statements:

i.

Signs and symptoms of TMD occur in healthy individuals

ii.

Signs and symptoms of TMD increase with age, particularly
during adolescence. Thus, TMD that originates during
[orthodontic] treatment may not be related to the treatment.

iii.

Orthodontic treatment performed during adolescence generally
does not increase or decrease the chances of developing TMD
later in life.

iv. The extraction of teeth as part of an orthodontic treatment plan
does not increase the risk of developing TMD.


v.

There is no elevated risk for TMD associated with any
particular type of orthodontic mechanics.

vi.

Although a stable occlusion is a reasonable orthodontic
treatment goal, not achieving aspecific gnathologically ideal
occlusion does not result in TMD signs and symptoms.

vii.

No method of TM disorder prevention has been
demonstrated.

viii. When more severe TMD signs and symptoms are present,
simple treatments can alleviate them in most patients.


Radiographic Diagnosis of
Temporomandibular Disorders


• Required to make an accurate diagnosis or to determine the
extent of involvement.
• Whether or not to order an imaging examination:
• (1) What the probability is that the imaging examination will
detect disease and its severity when it is present, or whether
it can pre-diet its future occurrence;
• (2) Which specific findings indicate the superiority of one
treatment over another; and
• (3) What findings may help predict the course and
prognosis of the disease with and without treatment.


• The ratio of true positive test results to the total number of
diseased individuals is called the sensitivity of the test.
• The ratio of true negative findings to the total number of
individuals in the nondiseased group is called specificity.
• High sensitivity without correspondingly acceptable specificity is
undesirable because low specificity is the result of excessive
false positive diagnoses, which could lead to overtreatment of
individuals not having disease.
•

It is generally considered that both sensitivity and specificity
should be greater than 0.70 for a Temporo mandibular disorder
(TMD) imaging test to be clinically useful.


• The direct visual examination is referred to as the gold standard
to which the imaging test in question is being compared.
• Other factors
1. cost,
2. invasiveness,
3. side effects,
4. the impact of the information gleaned on the treatment selection
process


Joint Anatomy Relative to Imaging
•

Diverse anatomy of the TMJ

•

Yale identified four markedly different naturally occurring
condyle morphologies, some of which might appear abnormal
on imaging to the inexperienced eye.

•

The mediolateral length of the condyle, averaging 20 mm,
prevents reproduction of the medial portions of the joint on
conventional, flat plane radiographs.

•

Adjacent dense osseous structures in and around the cranial
base are easily superimposed on the joint image, absorbing
radiation and degrading image clarity.


• Perhaps the most technically demanding anatomic obstacle to
overcome is the great variability in angulation of the long axis of
the condyle both in the horizontal and vertical planes.
• A five degree error in beam alignment can affect interpretation
of joint space width and degrade diagnostic quality.


Transcranial Radiographs

• Technique is simple and the required equipment is widely
available
• Used to evaluate the status of joint hard tissue and the spatial
relationship of the condyle to the fossa.


• The angulation in the vertical plane avoids superimposing the
dense structures in the cranial base on the joint image .
• The angulation in the horizontal plane, positions the central
beam parallel with the average horizontal condylar angulation.
• The corrected technique minimizes error by aligning the X-ray
beam with the condylar axis in the horizontal plane, the
angulation of which is measured on a submento-vertex
radiograph.
• Represents a profile view of the lateral third of the joint because
the central and medial portions of the joint are projected
inferiorly onto the condylar neck by the vertical angulation of the
X-ray beam.

• Poor sensitivity and specificity values
• TR is used as a screening aid for osseous lesions in the lateral
third of the joint.


Transmaxillary / transantral / transorbital / infraorbital
projection
• This technique provides a frontal view of the TMJ.
• The entire mediolateral profile of the condyle is imaged

.

• A disadvantage of the transmaxillary view is its failure to portray
most of the fossa, which is hidden by the shadow of the
eminence.


• The 40° angulation in the horizontal plane is required to avoid
superimposition of the mastoid process on the joint image.
• The 10° angulation in the vertical plane (B) avoids
superimposition of the hard palate and sphenoid bone.


• Larheim suggests that the transmaxillary view compliments the
lateral view, giving a good perspective of the entire joint
comparable to the more sophisticated and expensive
tomography


Tomography


• Horizontal angulation is individualized by measuring horizontal
condylar angulation on a submento-vertex radiograph and the
vertical angulation is measured on an anteroposterior
radiograph.
• The resulting tomographic plane closely approximates the true
perpendicular to the condylar long axis


• Tomography is generally accepted as being superior to plane
film radiography for assessing joint spaces and detecting
osseous lesions, especially when frontal as well as saggital
views are taken. However, early arthritic changes on the
condyle, and even more advanced changes in the fossa, are not
well detected.


Panoramic Radiography
• Image sharpness is typically less than with technically correct
plane film radiography.
• Advantages :cost effectiveness, availability, and relatively low
radiation dose
• Disadvantages : many early lesions will not be detected, and no
information on joint soft tissue status is provided.


Arthrography
• Arthrography is a technique used to highlight or outline joint
structures by using a radiopaque contrast medium to enhance
their images on plane or tomographic films.
• The contrast medium is injected into the upper or lower joint
space or both.
• The disc then appears as a radiolucent mass against the
background of contrast medium on conventional radiographs,
tomography, or fluoroscopy.


• Fluoroscopy allows for monitoring of the needle during the
injection procedure, viewing of dynamic disc movements, and
visualizing contrast material moving through existing
perforations.
• In cases of disc displacement with reduction on mouth opening
the dynamic movement of the disc during displacement and
reduction is dramatically evident.
• Arthrotomography – tomography when used with contrast
medium in the joint,


• The adaptation of arthrography to the TMJ was a crucial step in
our understanding of joint soft tissue dynamics and aided in
classification of internal joint derangements.
• It remains the only imaging method providing reliable
information on perforations.
• Disadv :
• invasive procedure
• discomfort for the patient associated with injecting the
contrast medium, and probably its presence in the joint
affects joint dynamics and
• method is technique sensitive.


Computed tomography (CT)


• Density differences between muscle, capsule connective tissue,
and the disc are relatively subtle under the normal CT operating
mode, and not well differentiated.

• Discs in normal position are often lost in the background of the
immediately adjacent high


Magnetic Resonance Imaging
• Advantages :
• The substitution of relatively harmless superconducting magnets
and radio wave energy for the well known hazardous of ionizing
radiation.
• The material of high contrast is soft tissue.

• High cost


Classification of TMD’s


Classification
I.
•

•

Masticatory muscle disorders
Acute myalgic disorders
•
Protective co – contraction
•
Local muscle soreness
•
Myofascial pain
•
Myospasm
•
Myositis
Chronic myalgic disorders
•
Fibromyalgia


II.

Temporo mandibular joint disorders
1.
Derangement of condyle disc complex
1.
Disc displacements
2.
Disc dislocation with reduction
3.
Disc dislocation without reduction
2.
Structural incompatibility of articular surfaces
1.
Deviation in form
1. Disc /condyle /fossa
2.
Adhesions
1. Disc to condyle
2. Disc to fossa
3.
Subluxation
4.
Spontaneous dislocation


3.

1. Synovitis
2. Capsulitis
3. Retrodiscitis
4. Arthritides
1. Osteoarthritis
2. Osteoarthrosis
3. Polyarthritides
5.
Inflammatory disorders of associated structures
1. Temporalis tendonitis
2. Stylomandibular ligament inflammation


III.
•

•

•

Chronic mandibular hypo mobility
Ankylosis
•
Fibrous
•
Bony
Muscle contracture
•
Myostatic
•
Myofibrotic
Coronoid impedence


IV.
•

•

Growth disorders
Congenital and developmental bone disorders
•
Agenesis
•
Hypoplasia
•
Hyperplasia
•
Neoplasia
Congenital and developmental muscle disorders
•
Hypertrophy
•
Hypotrophy
•
Neoplasia


Treatment of TMD


• Definiftive therapy: elimination / alteration of etiologic factors
responsible for disorder.
• Supportive therapy : directed towards alteration of symptoms.

• Etiology – “event”
• Local trauma to tissue
• Orthopedic instability – occlusal interferences - bruxism
• Increased stress
• All initial therapy should be conservative, reversible, non
invasive


• Occlusal therapy :
• Reversible occlusal therapy: occlusal splint that alters
mandibular position and contact pattern of teeth – creating
harmony with optimum condyle-disc fossa relationship – hence
providing orthopedic stability
• Muscle relaxation appliance – splint at CR position
•
•
•
•

Irreversible occlusal therapy :
Orthodontic treatment
Selective grinding and restorative procedures
Surgical alteration of jaw position.


• Emotional stress therapy
• Patient awareness
• Voluntary avoidance
• Relaxation therapy – self hypnosis, meditation, yoga,
Biofeedback technique


• Supportive therapy
• Pharmacologic therapy
• Analgesics – NSAID’s
• Antianxiety drugs
• Antiinflammatory agents – NSAID’s, corticosteroids
• Muscle relaxants
• Local anesthetics
• Physical therapy
• Thermotherapy
• Muscle coolant therapy
• Ultrasound therapy
• Electrogalvanic stimulation therapy
• TENS


•
•
•
•
•
•

Acupuncture
Cold laser
Manual techniques –
Massage – superficial and deep
Muscle conditioning
Passive and active muscle stretching


Clinical diagnosis and Management


Masticatory muscle disorders
•
•

Most common complaint of patient- muscle pain associated with
manual palpation or functional manipulation of muscles.
Restricted mandibular movements

•
•

Protective co contraction / muscle splinting :
Guarding / protective mechanism.

•

Is CNS response to injury or threat to injury

•

In the presence of an event the activity of appropriate muscles
is altered to protect the injured part from further injury.

•

CNS increases the activity of antagonistic muscles during
contraction of agonist muscle

• Etiology :
• Altered sensory or proprioceptive input
• Constant deep pain input
• Increased emotional stress
• History : recent injury

• Clinical characteristics
• Myalgia – not major complaint.
• Structural dysfunction – slow mouth opening reveals near
normal range of movements
• No pain at rest
• Increased pain with function
• Feeling of muscle weakness


• Management
• Definitive therapy
• As is a protective response, no indication to treat muscle
condition itself.
• Treatment should be directed towards etiology
• Correction/ elimination of altered sensory inputs
• Identify and address the deep pain
• Control of emotional stress
• Initiated when etiology is trauma
• Restrict the use of mandible to within painless limits
• Soft diet
• Simple muscle relaxation therapy, pain killers.


• Local muscle soreness / non inflammatory myalgia:

• First response of muscle to continued protective co-contraction.
• Represents a change in local environment of muscle tissues

• Etiology
• Prolonged co contraction
• Trauma
• Local tissue injury – injections, tissue strains
• Unaccustomed use
• Pain modulation phenomenon – altered pain sensations/
referred symptoms.
• Idiopathic myogenous pain


• Cyclic muscle pain condition
Trauma

Protective co-contraction

Local muscle soreness
Deep pian


• Structural dysfunction - slow mouth opening reveals limited
range of movements
• No pain at rest
• Actual muscle weakness
• Local muscle tenderness


• Management
• Decrease sensory input of pain to CNS
• Soft diet, smaller bites and slower chewing encouraged.
• Pt. encouraged to use muscles to within painless limits
• Occlusal disengagement
• Pt. Should be made aware of subconscious oral habits
• Occlusal appliance therapy
• Elimination of deep pain input.


• Supportive therapy :
• Reduce pain
• Analgesics for 7-10 days to break the cyclic effect of deep
pain
• Manual physical therapy –
• Passive muscle stretching, gentle massaging
• Relaxation therapy to reduce stress


• Myofascial pain ( trigger point myalgia)
• Regional myogenous pain condition characterized by local
areas of firm, hypersensitive bands of muscle tissue called
trigger points.
• First described by Travell and Rinzler in 1952.
• It was suggested that certain nerve endings become sensitized
by algogenic substances that create localized zone of
hypersensitivity.
• Local increase in temperature at site of trigger point –suggests
increase in metabolic demand / reduction of blood flow .
• A trigger point is a circumscribed region in which relatively few
motor unit are in contraction ( myospasm- all motor units
contract).

• Trigger points are a source of constant deep pain and produce
central excitatory effects - referred pain in particular predictable
pattern according to location of involving trigger points.
• Etiology :
•
•
•
•
•
•
•

Prolonged local muscle soreness
Constant deep pain
Increased emotional stress
Sleep disturbances
Local factors – habits, posture, strains
Systemic factors - viral infections, fatigue, hypovitaminosis
Idiopathic trigger point mechanisms

• History : misleading - patient will complain of heterotrophic pain
and not actual source of pain.


•

Clinical characteristics :
• Structural dysfunction
• Pain at rest
• Presence of trigger points
• Tenderness on palpation of trigger points and elicitation of
referred pain
• Trigger points become dormant /latent ,get activated by
factors such as flu, upper resp.tract infections, increased
heat, cold etc.
• Referred pain
• Secondary hyperalgesia – sensitivity to touch of scalp.
• Protective co-contraction
• Autonomic responses – tearing / drying of eyes, nasal
discharge, blanching of tissues – on same side of pain


• Management
• Definitive treatment
• Eliminate / reduce etiologic factors
• Eliminate local muscle soreness
• Reduce local and systemic factors contributing to myofacial
pain
• Sleep disturbances – sedatives, tricyclic antidepressants –
Amitryptiline 10 mg before bedtime.
• Treatment and elimination of trigger points – painless
stretching of muscle containing trigger points
• Spray and stretch
• Vapocoolant ( fluoromethane spray sprayed in
direction of referred symptoms and then muscle
stretched
• Cutaneous nerve stimulation temporarily reduces
pain in the area.


• Pressure and massage
• Increase pressure to trigger point to 10 lbs for 30 – 60
secs.
• If painful, discontinue
• Ultrasound and electrogalvanic stimulation
• Ultrasound – produces deep heat causing local muscle
relaxation
• High –volt electrogalvanic stimulation rhythmically
pulsates the muscle to levels of fatigue, causing muscle
relaxation.
• Injection and stretch
• 2% lignocaine without vasoconstrictor
• Eliminates immediate pain
• it is diagnostic of the site of origin of pain.


• Muscle relaxants
• Analgesics
• Regular exercise


• Myospasm :
• CNS induced tonic muscle contraction
• Etiology
• Protracted local muscle soreness
• Abuse of trigger point pain
• Muscle fatigue and local electrolyte balance changes
• Systemic conditions
• Deep pain input

• History :
• Sudden onset of pain, tightness and change in jaw position
with muscle rigidity


• Clinical manifestations :
• Structural dysfunction
• Marked restriction of range of movement
• Acute malocclusion
• Pain at rest
• Muscle tightness
• Local muscle tenderness


• Management :

• Definitive treatment
• Reduce pain and passively stretching involved muscle
• Eliminate etiologic factors
• Physical therapy – massaging and passive stretching
• Pharmacologic therapy is not indicated because this is an
acute condition.


• Myositis (inflammatory myalgia)

• Inflammation of muscle tissue
• Non infectious myositis
• Infectious myositis
• History :
• Duration of pain – long history of myogenous pain
• Constancy of pain - pain present even at rest


• Management
• Reduction of symptoms is slow and not dramatic as is a
inflammatory condition and takes time to resolve.
• Elimination of etiology – will slowly resolve inflammation and
reduce symptoms slowly
• Soft diet, smaller bites and slower chewing encouraged.
• Pt. encouraged to use muscles to within painless limits
• Avoid exercise and / or injections
• Occlusal disengagement
• Occlusal appliance therapy
• Anti-inflammatroy therapy – NSAID’s


• No physical therapy – as any movement cause pain
• Moist heat/ice therapy
• as symptoms begin to resolve Ultrasound therapy and gentle
stretching can be begun.
• As treatment takes time – hypotrophic changes and myostatic
contractures can develop.
• Isometric jaw exercises, passive stretching can be done
once acute symptoms are resolved.


• Fibromyalgia
• Chronic musculoskeletal disorder
• History
• Chronic generalized musculoskeletal pain in numerous sites
throughout body
• Patient presents with sedentary lifestyle
• Etiology
• Constant deep pain
• Emotional stress


• Clinical manifestations :
• Generalized Structural dysfunction
• Marked restriction of range of movement
• Pain at rest
• Presence of tender points – which do not induce
heterotrophic pain
• Sedentary physical condition


• Management :
• Treatment should be conservative
• As it is not primary masticatory muscle disorder, proper referral
for rheumatology, psychology, physical therapy must be made.


Masticatory muscle model


Temporomandibular joint disorders
• Internal derangement is a condition characterized by either an
abnormal anatomic disc-condyle relationship, or a normal
relationship associated with disc immobility.
• Arthralgia, Dysfunction symptoms are associated with condylar
movement and reported as sensations of clicking, catching of
joint- constant and repeatable and some times progressive
• Are divided into
• Derangement of condyle disc complex
• Structural incompatibility of articular surfaces
• Inflammatory disorders

• Internal derangements can be classified into four stages.
• The earliest stage involves an incoordination phase, - not
associated with joint pain or noise, and is only recognized when
patients are asked if their jaw joint moves smoothly and they
reply that they feel a slight catching or binding sensation.
• The onset of limited mouth opening associated with adhesion of
the disc to the fossa in a relatively normal position
• The next stage is anterior or anteromedial displacement of the
disc, which returns to a normal relationship with the condyle
during the opening movement and is associated with a clicking
or popping sound.


• If the degree of disc displacement progresses,reduction to a
normal relationship on mouth opening does not occur, the
patient's jaw is locked, and opening is initially limited to 23 to 25
mm
• This stage is not characterized by joint clicking or popping


Derangement of condyle disc complex
•

•
•
•
•

Etiology:
•
Breakdown of normal rotational function of disc on
condyle.
•
Elongation of discal collateral ligaments and inferior
retrodiscal lamina
•
Thinning of posterior border of disc
•
Trauma
Types
Disc displacements
Disc dislocation with reduction
Disc dislocation without reduction


• Disc displacements:

Inferior retrodiscal lamina and discal collateral ligament –
elongated
Disc can be positioned anteriorly by superior pterygoid muscle
+ thinning of posterior border of disc
Disc anteriorly positioned

Abnormal translatory shift of mandible during opening
[ click ]

• History :
• trauma ^ joint sounds
• Pain - +/- ( intracapsular and concomitant with click, directly
related to joint function)

• joint sounds
• Reciprocal clicking- two clicks at different degrees of
opening and closing click- near intercuspal position.
• Normal range of jaw movements


• Disc dislocation with reduction:
Inferior retrodiscal lamina and discal collateral ligament – further
elongated +
posterior border of disc sufficiently thinned

Disc slip/forced completely through the discal space,
condyle and disc not articulating
 If patient can manipulate the jaw so as to reposition the condyle
on the posterior border of disc- disc is reduced.


• History:
• Long history of clicking ,recent catching sensation.
• Pain +/• Clinical characteristics :
• Unless the jaw is shifted to the point of reducing the disclimited range of opening
• Opening reduces the disc – deviation in path of opening
• After disc is reduced – normal range of mandibular
movements present.
• Click – at piont of recapturing of disc.


• Disc dislocation without reduction :
• Elasticity of superior retrodiscal lamina lost – recapturing of disc
more difficult
• When disc is not reduced ,forward translation of condyle pushes
the disc in front of condyle.
• History
• Patient knows when dislocation has occurred.
• H/O Clicking before the locking
• Restricted jaw opening- closed lock jaw
• Pain – when trying to open beyond joint restriction
• Clinical characteristics :
• Limited jaw movement
• Pain – when trying to open beyond joint restriction
• Pain when loading joint bilaterally manually

• Management
• Disc displacements and Disc dislocation with reduction
• Reestablishment of normal disc – condyle relationship
• Farrar ( early 1970’s)introduced anterior repositioning
appliance, which provides an occlusal relationship that requires
the mandible to be positioned forwardly, that will reestablish the
normal disc condyle relationship.
• This anterior repositioning will recapture the disc onto the
condyle.
• Worn 24 hrs /day for 4 – 6 months.
• This appliance reduced painful joint symptoms by improving
disc - condyle relationship.
• What next ?????


•

Two different belief systems existed.

1.

Mandible to be permanently repositioned in this position
• Occlusal adjustments

2.

Once the discal ligaments are repaired, the mandible should
be returned to musculoskeletally stable position and the disc
would remain in proper position.

•

Neither was supported by long term data


• In early short term studies, the anterior repositioning appliance
proved to be much more effective in reducing intracapsular
symptoms than the more traditional muscle relaxation
appliance.
• This, lead the profession to believe that returning the disc to its
proper relationship with the condyle was an essential part of
treatment.
• The long term studies reveal that that anterior repositioning
appliances are not effective
• They are helpful in reducing painful symptoms in 75% cases,
but joint sounds are more resistant to therapy and do not always
indicate a progressive disorder.

•

Anterior repositioning appliance cannot recapture the disc,
instead as the condyle returns to the fossa, it posteriorly to
articulate on adaptive retrodiscal tissue.

•

If the tissues are adequately adapted, loading occurs without
pain.

•

Result is painless joint with clicking on condylar movement.

•

Earlier, dental profession believed that presence of join t sounds
indicated treatment failure.

•

Studies show that Some dysfunction is likely to persist once the
joint structures are altered.

•

Controlling pain while aloowing joint strucutres to adapt is the
most important role of the therapist.

• A few long term studies do support that permanent alteration of
occlusal conditions is successful in controlling major symptoms.
• Such treatment regimen should be reserved only for those
patients with significant orthopedic instability


• Disadvantage of use of ARA –
• development of posterior open bite – due to reversible
myostatic contracture of inferior lateral pterygoid muscle.
• Gradual re- lengthening of the muscle can be accomplished
by slowly stepping back the condyle to more stable
anterosuperior position in fossa.
• Can be done by
• Adjusting the appliance to allow the condyle to return to
musculoskeletally stable position
• Slowly decreasing use of appliance.
• Degree of myostatic contracture α length of time
appliance is worn
• Only night time wearing – gradually reduced as
symptoms reduce.


• In some pts, posterior open bites develop even after careful use
of appliance.
• Causes
• Myofibrotic contracture of inferior lateral pterygoid muscle.
• Thickened retrodiscal tissue- not allow the condyle to seat in
fossa
• Preexisting orthopedic instability.


• Main aim is to Reduce intracapsular pain not recapture the disc.
• Muscle relaxation appliance
• Anterior repositioning splint
• Night /day wear( less time – minimal occlusal effects.), reduce
as symptoms resolve.
• Elimination of appliance – return of symptoms
• – not enough time given for adaptive process
• - there is orthopedic instability – dental therapy indicated.


•
•
•
•
•

Supportive therapy :
Decrease loading of joint – soft diet, slower chewing etc.
Not allow joint to click.
If inflammation present – NSAID’s
Passive exercises.


• Disc displacements without reduction:
• Definitive therapy:
• Initial therapy include - Recapture disc by manual manipulation
• Success depends on three factors :
• Level of activity of superior lateral pterygoid- it has to be fully
relaxed – local anesthetic injection if remains active due to
pain / dysfunction
• Disc space increased – relaxation of elevator muscles
• Condyle must be maximum forward translatory position for
maximum activity of superior retrodiscal lamina activity.


•

Reduce displacement without assistance –move mandible to
contra lateral side and then open moth maximally.

•

Reduced by operator by applying downward forward distraction
force on condyle.
Once reduced – ARA given .

•


• If disc does not reduce – superior retrodiscal lamina lost its
elastic property
• Conservative approach first attempted -Muscle relaxation
appliance - encourages adaptation of retrodiscal tissues.
• If this fails – surgical procedures considered.


• Surgical considerations for condyle disc derangement disorders:
• Conservative methods
• Arthrocentesis
• Pumping the joint
• Arthroscopy
• Arthrotomy – open joint surgery
• Plication
• Discectomy
• Discal implants
• Silastic implants
• Proplastic teflon discal implants
• Dermal and auricular cartilage grafts


Structural incompatibility of articular surfaces
•
•
•
•

Etiology
Macrotrauma
Trauma causing hemarthrosis
Surgical intervention

•

Types
1. Deviation in form
1. Disc /condyle /fossa
2. Adhesions
1. Disc to condyle
2. Disc to fossa
3. Subluxation
4. Spontaneous dislocation

Deviation in form :
• Actual changes in shape of articular surfaces
• Disc – thinning or perforations
• condyle /fossa flattening
•
•

Clinical Characteristics:
Repeatable observation at a repeatable point of
opening

•
•

Management :
Surgical approach
• Bony incompatibility – bone smoothened and
rounded
• Discoplasty


• Adhesions :
• Prolonged static loading of joint – exhausts weeping lubrication
of joint
• Hemarthrosis

• History :
• Temporary adhesions: catching sensation limited opening afetr
prolonged static loading of joint
• Click/popping sound
• Return of normal joint function
• Permanent adhesions: Reduced function , pain on opening
more- stretching of ligaments


• Clinical Characteristics :
• Adhesions in superior joint cavities :
• Limited opening – only rotatory movements of condyle as
translatory movements inhibited
• No pain on bilateral manipulation.
• Fixed disc /Posterior dislocation of disc :
• Normal opening with restriction during closing
• Deviation during closure
• Adhesions in inferior joint cavity :
• Difficult to diagnose
• Patient can open to normal interincisal distance but senses
a catching or jumping on way to maximum opening.


•
•
•
•

Management :
Muscle relaxation appliance
Permanent adhesions - Arthroscopic surgery
Supportive therapy to alleviate he pain and dysfunction.


• Subluxation / Hyper mobility :
• Condyle movement beyond crest of eminence – jump forward to
wide-open position.
• Articular eminence anatomy – steep posterior slope and long
anterior slope.
• History :
• Jaw ‘goes out’ whenever pt opens wide
• Clinical features
• Repeatable phenomenon
• No pain – unless abused
• Examination – at later stage of opening condyle will jump
forward leaving depression/ void behind it.


• Management :
• Surgical alteration of joint itself
Eminectomy – reduces the steepness of articular
eminence, hence reduces the posterior rotation of condyle
during full translation.


• Spontaneous dislocations :
• Hyperextension of TMJ leading to anterior dislocation of disc.
• Premature activity of superior pterygoid muscle- forward pull of
disc through anterior disc space – spontaneous anterior
dislocation
• Associated with long dental appointments
• Pt cannot close mouth
• Pain present
• Called open lock


• Management :
• Treatment is directed towards increasing disc space- allows the
superior retrodiscal lamina to retract the disc.


•

Synovitis/ Capsulitis / Retrodiscitis:

•

Inflammation of synovial tissue or capsular ligament or
retrodiscal tissue.

•
•

Etiology : trauma ,repeated abuse
Clinical features:
• Continuous deep pain accentuated by function
• Tenderness on palpation
• Limited opening secondary to pain
• Edema- condyle displaced inferiorly – ipsilateral
posterior open bite.
• Retrodiscitis – edema displaces condyle forward and
down the eminence


• Management
• NSAID’s
• Hot fermentation
• Ultrasound therapy


Arthritides
• Inflammation of articular surfaces of joint

• Categorized into
• Osteoarthritis
• Osteoarthrosis
• Polyarthritides


• Osteoarthritis / Osteoarthrosis :
• Non inflammatory condition with deterioration of articular
surfaces and underlying bone due to mechanical overloading of
joint( more than condylar remodeling capacity.

• Active condition – Osteoarthritis
• As condylar remodeling occurs, condition is more stable – bone
morphology remains altered- Osteoarthrosis
• Two forms : primary or secondary form


• Primary disease is a gradually developing process and is
caused by the normal wear and tear to which the joint is
subjected.
• occurs bilaterally
• occurs in persons > 50 yrs
• The large weight bearing joints are most commonly involved.
• When the distal interphalangeal joints are involved
-enlargements are called -Heberden's nodes.
• proximal interphalangeal joints -Bouchard's nodes.
• Primary degenerative disease of the TMJ is generally
asymptomatic, although patients may occasionally complain of
joint stiffness, crepitation, and mild pain.

• Secondary degenerative joint disease
• 20 -40 years of age.
• It is caused by a speeding up of the degenerative process by
trauma, persistent parafunction, or increased stress on the joint
produced by loss of teeth or severe malocclusion.
• It is characterized by TMJ pain, joint tenderness, limitation of
mouth opening and, in the late stages - crepitation.
• Frequently unilateral.


• Radiographic changes :
• The earliest change is subchondral sclerosis.
• As the condition progresses, there is condylar flattening and
lipping, erosion, or osteophyte formation.
• In the late stages, breakdown of the subchondral bone gives
rise to a bone "cyst“ within the condyle.
• When the intra-articular disc becomes involved, there will be
narrowing of the joint space.
• Changes are more severe in the secondary than in the primary
form

• Polyarthritides :
• Group of disorders in which articular surfaces become inflamed.
•
•
•
•

Traumatic arthritis
Infectious arthritis
Rheumatoid arthritis
Hyperuricemia


Rheumatiod arthritis
• Pt complain of
• a deep, dull, aching pain in the preauricular region exacerbated by function,
• swelling of the preauricular tissues during the acute phases,
and progressive limitation of jaw movement.
• Severe destruction of the condyle occurs in the late stages - a
progressive Class II malocclusion and an anterior open bite
develop due to loss of ramal height.
• The radiographic features include
• a loss of the intra-articular joint space,
• condylar destruction,
• erosion of the glenoid fossa.


•
•
•
•
•

laboratory tests:
Test for rheumatoid factor
The erythrocyte sedimentation test
The presence of antinuclear antibodies,
The presence of HLA-DW5 and HLA-DR8

•
•
•
•
•
•
•

Juvenile form - under 16 years of age.
two peaks of onset - ages of 1-3 yrs and 8 -12 yrs.
three subtypes:
systemic (Still's disease),
Polyarticular – most common
pauciarticular.
a characteristic feature is micrognathia and a Class II
relationship, referred to as a birdface deformity.
• Ankylosis is more common with juvenile rheumatoid arthritis
than with the adult onset type.


• Inflammatory disorders of associated structures
• Temporalis tendonitis – prolonged activity of temporal
muscle
Unilateral , Constant pain in temple region, aggravated
during function
Restricted jaw opening
Intraoral palpation of temporal tendon produces pain
• Stylomandibular ligament inflammation:
Intraoral palpation- tender


Chronic mandibular hypomobility
• Long term painless restriction of mandible.
• Pain elicited on if forceful opening beyond limitations is
attempted.

• According to etiology
• Ankylosis
• Muscle contracture
• Coronoid process impedence


•
•
•
•
•

Ankylosis
Bony / fibrous intracapsular adhesions.
Restricted mandibular movements.
Etiology- macro trauma, hemarthrosis, surgery
If unilateral- ipsilateral deviation of mandible.

• Muscle contracture :
• Clinical shortening of resting length of muscle without interfering
with in its ability to contract further.
• Painless limitation of mouth opening.
• Myostastic contracture : results when muscle is kept from fully
relaxing( due to pain in associated structure) for prolonged time.


• Myofibrotic contracture :
• Excessive tissue adhesions within muscle or its sheath
• Follows myositis / trauma to muscle

• Condylar impedance:
• Protrusive movements especially limited
• Trauma /infection in area anterior to coronoid process – leading
to fibrous adhesions in these tissues.


•

Management :

•
•

Ankylosis :
Surgical treatment – arthroscopic surgery

•
•
•
•

Muscle contractures
Passive stretching exercises
Resistant opening exercises
Surgical detachment and reattachment of muscles

•
•
•

Coronoid impedence
Ultrasound therapy with passive stretching exercises
Surgery contraindicated

•

No supportive therapy indicated as all are asymptomatic
conditions

Conclusion
• Much of the difficulty encountered by clinicians in successfully
treating TMD patients is based on diagnostic inaccuracy and,
therefore, considerable emphasis has to be placed on the
proper recognition of the various temporomandibular disorders.
• Faced with a variety of imaging techniques, the clinician needs
to decide when imaging should be used and the accuracy of the
information that the imaging will provide.
• In addition to accurate diagnosis, having an understanding of
the etiology of a condition is helpful in determining therapy.


• Of the various conditions encountered in the orthodontic patient,
the two most common are masticatory myofascial pain and
dysfunction and the internal derangements of the
temporomandibular joint.
• These conditions are of particular concern, not only because
their presence may require modification in orthodontic
treatment, but also because there have been claims that they
can be caused by such therapy .
• Hence , a rational approach to the general management of
these conditions is required

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