Temporo Mandibular joint (TMJ) importance in orthodontic treatment /certified fixed orthodontic courses by Indian dental academy

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•INTRODUCTION
•CLASSIFICATION OF JOINTS
•EVOLUTION OF TMJ & JAWS
•DEVELOPMENT OF TMJ
•MUSCLES OF MASTICATION
•TMJ ANATOMY
•HISTOLOGY
•BIOMECHANICS OF TMJ
•EXAMINATION OF TMJ
•DIAGNOSTIC IMAGING
•TMD
•CONCLUSION
•REFERANCES

INTRODUCTION

Why study TMJ as an orthodontist ?
The TMJ influences the function, esthetics, &
structural harmony of the teeth, dentition, face
and thus a person in total.
Therefore an understanding of the anatomy ,
physiology, biomechanics etc., of the masticatory
system is very much necessary.

The masticatory system or the somatognathic
system consists of the skull bones, mandible,
hyoid, clavicle, sternum; the masticatory
muscles,& ligaments; the dentoalveolar complex;
the vascular, neural & lymphatics and the TMJ.
The masticatory system is responsible for
CHEWING, DEGLUTATION, SPEECH, etc…………

Classification of Joints
1.SYNARTHROSIS:
(i) FIBROUS JOINTS
A: SUTURES (collagenous sutural ligament)
B: SYNDESMOSES (collagenous ligament + elastic fibrous tissue)
C: GOMPHOSES (complex fibrous & cellular periodontium)
(ii) CARTILIGENOUS JOINT
A: SYNCHONDROSIS (hyaline cartilage)
B.SYMPHYSES (hyaline cartilage+ fibrocartilagenous disk)
(iii) SYNOSTOSES (rigid bony unions)
2. DIARTHROSES:
SYNOVIAL JOINT (Synovial fluid present between articulating surfaces)

Classification of Joints
•FIBROUS
•CARTILAGENOUS
•PRIMARY
•SECONDARY
•SYNOVIAL

Temperomandibular joint
“Nothing is more fundamental in treating patients
than knowing the anatomy.”
- Okeson
Most human bones are connected to each other by
JOINTS or ARTICULATIONS. Some of them being
mobile while being immobile.
In the mobile joints the surfaces are covered by
cartilage & fibrous tissue forming a capsule.the inner
lining cells secrete SYNOVIAL fluid that allows
freedom for the joint to move.

•TEMPEROMANDIBULAR JOINT IS A COMPOUND,
BICONDYLAR, GINGLIMO-ARTHROIDAL, ELIPSOIDAL,
SYNOVIAL JOINT.
•IT IS A WEIGHT BEARING JOINT. IT BEARS
ABOUT 500N OF FORCE.
•THE TMJ IS LOADED MORE IN THE NON WORKING
CONDITION THAN IN WORKING SIDE.
•TMJ IS ONE OF THE MOST COMPLICATED JOINTS
IN THE BOBY AND IT IS FORMED BY THE
ARTICULATION OF THE MANDIBLE TO THE
CRANIUM.
•THE MANDIBULAR CONDYLAR HEADS FITS INTO
THE GLENOID FOSSAE OF THE SQUAMOUS PART OF
THE TEMPORAL BONE INTERPOSED BY AN
ARTICULAR DISC IN BETWEEN.

An Amphibian jaw-
articulation b/w the terminal
portion of Meckels cartilage
& the palatoquadrate bar.
Teeth are confined to the
dentary bone
A Reptile jaw- dentary is of
increased size Fossil Mammal like Reptile-
enlarged dentary & has coronoid
process
Mammals- Articulation of dentary
with the temporal bone &
constitutes part of inner ear.

Embryology –
Cranial most part –enlarges
Two big bulging in the
ventral aspect of the
embryo.
Depression - Stomatodeum
Neural groove – 21st day
Closure of neural tube –
23rd day

1st arch – Mandibular arch
2nd arch – Hyoid arch
3rd arch
4th arch No Names
6th arch
5th arch – Disappears soon after
formation.

1st – Meckels cartilage ,
incus & malleus , also ant.
lig. of malleus &
Sphenomandibular lig
2nd - Stapes , Styloid
process , Stylohyoid lig ,
Smaller cornu of hyoid ,
Superior part of body of
hyoid.
3rd – Greater cornu of
hyoid bone , lower part of
the body of hyoid bone.
4th & 6th – Cartilages of
larynx.

4th to 28 weeks

Development of TMJ →
Acc to Baume, temporomandibular articulation originate
from two different blastema.
The Condylar blastema & the Temporal blastema.
Condylar blastema –(primodium of the mandible)
- condylar cartilage
- the aponeurosis of the external pterygoid
muscle
- the disc
- the capsular elements of the lower joint.

Temporal Blastema –
- Articular structures of the upper level
Condylar blastema forms at the distal end of
the primordium of the mandible.
The mandible begins to ossify – 7th week of
fetal
life / 19mm stage of fetal development.
22mm stage / 8th week – bone laid down in a
platelike form lateral to Meckels cartilage.

week IU
Meckels cartilage extends
from the Cartilaginous otic
capsule to the midline
symphysis bone of the
mandible is forming in the
membrane
Tongue
Meckels cartilage

Phylogenetically , the developing middle ear in
primates & especially the humans was the
initial jaw joint of the vertebrates
In the middle ear region that the malleus &
probably the incus develop as posterior
extensions of Meckels cartilage.
The intermediate portion of Meckels cartilage
disappears, but its sheath remains to persist
in the form of anterior malleolar ligament &
the sphenomandibular lig.

A -relationship b/w A -Anterior
malleolar lig.
mandible & middle
ear. B -Malleus
B -reference to C - Incus
Meckels cartilage.

24mm stage embryo, the pterygoid & masseter
muscles have differentiated.
At the superior border of the external pterygoid
muscle & just below to the masseter muscle, a
layer / bulk of mesenchyme tissue which is the
analogue of articular disc.
28mm stage the middle ear ossicles are fully
formed in true cartilage & malleus is continuous
with the Meckels cartilage.
-Articular disc & external pterygoid tendons are
attached to the malleus.

11th week – condylar cartilage becomes
evident, located at the upper end of the
posterior border of developing mandible.
30mm stage embryo – articular surface faces
directly lateral, it is parallel to the articular
disc as well as to the articular surface of the
zygomatic process of the temporal bone.
50mm stage – condylar cartilage shapes the
articulating surface of the condyle in a
hemisphere.

- Articular disc has flattened & the plane of the
articular surfaces has undertaken a shift of 450
- 55mm stage – condylar head produces an
osseous head which matures into condylar
cartilage by 65mm stage – Baume.
- 85mm stage – ossification of the cartilage
begins, growth center of the mandible.
- joint cavity formation is evident as the loose
connective tissue on either side of the future
articular disc becomes less dense.

Inferior portion of the joint cavity takes the
shape of a distinct cleft.
13th week – the lower joint cavity is well
formed around the superior surface of the
condyle, so as the upper part.
15th week – vascular mesenchyme of the
condylar cartilage can be seen breaking
down.
- both joint cavities are formed.

At 155mm stage – differentiation continues
anteriorly to arrive at a point of full
articulation.
190mm stage – all the elements of the joint
are fully formed.
Baume, full differentiation of all articular
elements by 4th fetal month.

Parietal
bone
Occipital
Frontal bone
Squamous
Part
Secondary
Secondary
condylar
coronoid cartilage
Cartilage
Ramus
Maxilla
Body of
14 weeks of Human Fetus

8th – 10th weeks IU – proliferation & histodifferentiation takes
place & condyle assumes its mature morphogenic pattern.
Also 1st evidence of temporal bone
12th – 14th week IU – formation of articular disc
22nd week IU – both articular eminence & the glenoid fossa
are well formed
Meckels cartilage plays no role in actual dev of TMJ, acts as
a frame work / scaffold for the dev mandible.
Ramus formed of membranous bone & endochondral bone
formation at the head of the condyle.
Early attachment of muscles of mastication – 8th week.
Attachment of external pterygoid – 13th week.
Masseter muscle attachment – 14th week.

Joint Innervation –
Kitamura;
- branches of Auriculotemporal nerve,
masseter
nerve, & the posterior deep temporal
nerve
Branches of Mandibular portion of Trigeminal
N.
4th fetal month – nerve fibers may be
observed in the articular capsule

5th month – appear to reach the disc.
6th month – widest distribution over the
condyle & within the disc.
Localization & distribution of nerve fibers at
joint margins.
Nerve fibers in capsule innervate the synovial
membrane of the joint as well.

Du Brul;
- the key relationship b/w jaw & ear dysfunction lies
in the embryological development of the neural
patterns of the TMJ.
- demonstrated that the nerve to the internal
pterygoid muscle also sends a branch to tensor
tympani muscle (moves the malleus)
He states unequivocally that, “ Herein lies the key to
the relationship b/w jaw & ear dysfunctions
sometimes plaguing modern man along with the
deteriorating of other parts of jaw & dental
apparatus”

A – Mandible at birth
B – At 6 years Lateral View
C – In an Adult

Occulsal View
A- At birth
B- At 6 yrs
C- Adult

MUSCLES OF MASTICATION
- MASSETER
- TEMPORALIS
- LATERAL PTERYGOID
-MEDIAL PTERYGOID

INTRODUCTION
Moves the mandible during chewing and
speech.
These are SKELETAL, VOLUNTARY muscles.
Consists of
- Masseter
- Temporalis
- Lateral Pterygoid
- Medial Pterygoid
- Buccinator (accessory /5th muscle)
- Ant. belly of digastric, geniohyoid,mylohyoid,
hyoglossus & to some extent sup.constrictor
of pharynx.

MUSCLES OF MASTICATION

DEVELOPMENT
It develops from the mesoderm of the
1st PHARANGIAL ARCH.

MASSETER
Quadrilateral muscle that covers lateral surface
of the mandible.
Has 3 layers: superficial, middle & deep.
Multipinnate arrangement of fibers

LAYERS ORIGIN FIBERS INSERTION
SUPERFICIAL: ANT.2/3 OF LOWER
BORDER
ZYGOMATIC ARCH &
ZYG. PROCESS OF
MAXLLLA.
- PASS
DOWNWARDS &
BACKWARDS AT
45º
LOWER PART OF
LATERAL
SURFACE OF
MAND.
MIDDLE: ANT. 2/3 OF DEEP
SURFACE & POST.
1/3 OF LOWER
BORDER OF ZYG.
ARCH.
- VERTICALLY &
DOWNWARDS.
MIDDLE PART OF
RAMUS
DEEP: DEEP SURFACE OF
ZYG. ARCH
UPPER PART OF
RAMUS AND
CORONOID
- 3 LAYERS ARE
SEPERATED BY AN
ARTERY & A NERVE

TEMPORALIS
Fills the Temporal Fossa.
MUSCLE ORIGIN FIBERS INSERTION
TEMPORALIS TEMPORAL
BONE AND
FASCIA
CONVERGE &
PASSES
THROUGH GAP
DEEP TO ZYG.
ARCH
- MARGIN & DEEP
SURFACE OF
CORONOID
- ANT. BORDERS
OF RAMUS OF
MAND.
 FAN shaped muscle.

LATERAL & MEDIAL PTERYGOID
LATERAL PTERYGOID:
It is a short & conical muscle.
Has upper & lower head.
MEDIAL PTERYGOID:
Quadrilateral muscle
Has superficial & deep head

LATERAL
PTERYGOID
ORIGIN FIBERS INSERTION
UPPER (SMALL) FROM
INFRATEMPORAL
SURFACE & CREST OF
G.WING OF SPHENOID
RUN BACKWARDS
& LATERALLY.
CONVERGE FOR
INSERTION
PTERYGOID FOVEA
(CONDYLAR NECK)
LOWER
(LARGER)
LATERAL SURFACE OF
LATERAL PTERYGOID
PLATE
ANT. MARGIN OF
ARTICULAR DISC &
CAPSULE OF TMJ.
MEDIAL
PTERYGOID
ORIGIN FIBERS INSERTION
SUPERFICIAL
(SMALL)
TUBEROSITY OF
MAXILLA & ADJOINING
BONE
DOWNWARDS,
BACKWARDS &
LATERALLY
MEDIAL SURFACE OF
ANGLE & RAMUS OF
MANDIBLE
DEEP
(LARGE)
MEDIAL SURFACE OF
LATERAL PTERYGOID
PLATE & ADJ.
PROCESS OF
PALATINE BONE
BELOW & BEHIND
MAND. FORAMEN &
MYLOHYOID
GROOVE

PTERYGOID
VENOUS PLEXUS
MUSCLE ARTERY VEIN NERVE
MASSETER MASSETRIC.A.
(II PART OF
MAXILLARY A.)
RESPECTIVE VEIN MASSETRIC NR.
(BR.OF ANT. DIV.OF
MAND.NR)
TEMPORALIS SUP. TEMPORAL A. DEEP TEMPORAL
(BR.OF ANT.
DIV.OFMAND.NR)
LATERAL
PTERYGOID
LAT. PTERYGOID.
(II PART OF
MAXILLARY A.)
MAXILLARY VEIN
LAT. PTERYGOID
(BR.OF ANT. DIV.OF
MAND.NR)
MEDIAL
PTERYGOID
MED. PTERGOID.
(II PART OF
MAXILLARY A.)
RETROMANDIBULAR
VEIN
MED. PTERYGOID
(BR. OF MAIN
TRUNK OF MAND.
NR.)
SUPPLIES:

TEMPORALIS MASSETER
MEDIAL PTERYGOID
PROTRACTION
LATERAL PTERYGOID
DIGASTRIC
GENIOHYOID
RETRACTION
MYLOHYOID
DEPRESSION
ELEVATION

Temporomandibular joint proper

The three major skeletal components that
make up the masticatory system :
Maxilla
Mandible
Temporal bone

Temporal
bone
A- mandibular fossa
B- external acoustic
meatus
C- articular eminence
D- zygomatic process
E- tympanic plate
F- petrosquamous
fissure

A- body A- genial spine (tubercles)
B- ramus B- internal oblique ridge
C- incisive fossa C- attach. area for medial
pterygoid
D- mental foramina D- temporal crest
E- angle E- retromolar triangle
F- external oblique line F- mandibular foramina
G- coronoid process G- lingula
H- condyle H- mylohyoid groove

Condyle
LP-
lateral pole
MP-
medial pole
pterygoid
fovea

line drawn through the centers of the poles of
the condyles, usually extends medially &
posteriorly towards the anterior border of the
foramen magnum.
1450

mm
The articulating surface of the condyle extends
both anteriorly & posteriorly to the most
superior
aspect of the condyle.
Posterior articulating surface is greater than
anterior surface & is quite convex
anteroposteriorly & only slightly convex
mediolaterally.

HISTOLOGY OF TMJ
- Histologically the appearance varies with age, due
to presence of secondary cartilage.
- This cartilage appears about 10th month IU &
remains as a zone of proliferating cartilage until
about the later half of the second decade of life.
- The condyle of the young child is not lined by a
distinct layer of compact bone as is that of the
adult.

A- fibrous articular layer
B- cell rich proliferative layer
C- hypertrophic condrocytes
of the secondary cartilage
D- woven bone being
deposited around
E- a template of calcified
cartilage
F- marrow space
-multinucleated
osteoclast
- osteoblast layer
depositing bone on
calcified cartilage.

A – head of adult condyle A – collagen fibers at the
centre
B – lower part of intraarticular B – regularly aligned at
periphery
disc C – larger marrow
spaces & lack of
a layer of compact
bone

Histology of articular
surface-
A – condyle head
B – fibrous articular
surface
zone
C – cellular rich zone
D – fibrocartilagenous
zone
E – zone of calcified
cartilage
F – lower joint space
G – intra articular space

Articular disc
- Composed of dense
fibrous connective tissue
- Extreme periphery of
the disc , is innervated
Sagittal plane –
AB- anterior border
PB- posterior border
IZ- intermediate zone

Anterior view –
the disc is slight
thicker medially than
laterally.
LP- lateral pole
MP- medial pole

-Sagittal section of the intra- - Adult intra articular
disc
articular disc of a neonate - shows sparse
distribution
-presence of numerous of cells
fibroblasts. - rounded cartilage -
like cells

ACL- anterior capsular lig. AS- articular surface
IC- inferior joint cavity ILP- inferior lateral pterygoid
muscles
IRL- inferior retrodiscal lamina RT- retrodiscal tissues
SC- superior joint cavity SLP- superior lateral
pterygoid
muscles
SRL- superior retrodiscal lamina
ELASTIC COLLAGENOUS

The articular disc is attached to the capsular lig. ,not
only anteriorly & posteriorly, but also medially &
laterally; this attachment divides the joint into ;
a) the upper cavity [superior cavity]
b) the lower cavity [inferior cavity]
Upper is bordered by, the mandibular fossa & the
superior surface of the disc.
Lower is by, the mandibular condyle & the inferior
surface of the disc.

Specialized endothelial cells forms a synovial lining
surrounding the internal surface of the cavities.
This lining along with a specialized synovial fringe
located at the anterior border of the retrodiscal
tissues, produce synovial fluid.
Synovial Fluid –
i) metabolic requirements to the non-vascular
articular surfaces of the joint.
ii) lubrication during function, reducing friction.

Lubrication –
i) Boundary lubrication
ii) Weeping lubrication
Boundary lubrication –
-when the joint moves, the synovial fluid is forced from one
area of the cavity to another.
-prevents friction & is the primary mechanism of joint lub.
Weeping lubrication –
-the ability of the articular surfaces to absorb a small amount
of fluid.
-forces during function drive a small amount of fluid in & out
of the articular tissues, helps in metabolic exchange.

Compressive forces - release fluid & prevents
sticking of articular tissues.
Weeping eliminates friction in compressed but not
moving joint.
But prolonged compressive forces will exhausts this
supply leading to deleterious effects.

Crimping of collagen
fibers in the intra
articular disc is
indicative of
tensional loads.
About 2/3rd s of the
glycosaminoglycan is
chondroitin sulphate
& 1/3rd is dermatan
sulphate, traces of
hyaluronan &
heparin sulphate.

Innervation of TMJ –
- The trigeminal nerve , that provides both motor &
sensory innervation to the muscles that control it.
- Afferent innervation – branches of the mandibular
nerve.
- Also by auriculo-temporal nerve as it leaves the
mandibular nerve behind the joint & ascends
laterally & superior to wrap around the posterior
region of the joint.
- Additional nerves – temporal & masseteric .

RUFFINI Posture
(proprioception)
Dynamic &
static balance
(capsule)
PACINI Dynamic
(mechanoreception)
Movement
accelerator
(capsule)
GOLGI Static
(mechanoreception)
Protection
(ligament)
FREE Pain
(nociception)
Protection
(joint)

Vascularization –
- predominantly ;
i) from posterior- superficial temporal
artery
ii) from anterior- middle meningeal artery
iii) from inferior- internal maxillary artery
iv) others ;
- the deep auricular
- anterior tympanic
- ascending pharyngeal arteries
- condyle, receives through its marrow spaces by
“feeder vessels” from inferior alveolar artery.

LIGAMENTS
Made up of collagenous connective tissues having
particular lengths & they do not stretch.
Act as passive restraining devices to limit & restrict
border movements.
The three functional ligs ;
i) the collateral lig
ii) the capsular lig
iii) the temporomandibular lig

AD- Articular disc
CL- Capsular
ligament
IC- Inferior joint
cavity
SC- Superior joint
cavity
LDL- Lateral discal lig
MDL- Medial discal lig

Collateral (discal ligaments) :
- Attaches the medial & lateral borders of the
articular disc to the poles of the condyles.
- Divides the joint mediolaterally into the superior &
inferior cavities.
- True ligs , do not stretch & restricts movement of
the disc away from condyle.
- Responsible for hinging movement of the TMJ.
- Have both vascular as well as innervation ,
providing information regarding joint position &
movement.
- Strain on these ligs produces pain.

Capsular ligament
- surrounds &
encompasses the
entire TMJ.
- superiorly to the temporal bone along the borders of
the articular surfaces of the mandibular fossa &
articular eminence.
- inferiorly – neck of the condyle
- resist any medial, lateral / inferior forces that tend to
separate / dislocate the articular surfaces.
- helps to retain synovial fluid & provides proprioceptive
feedback.

Temporomandibular (Lateral) ligament
IHP-
Inner horizontal
portion
OOP-
Outer oblique portion
Oblique portion – resists excessive dropping of the
condyle
- normal opening of the mouth.
- wider mouth opening- the condyle moves
downwards & forward across the articular
eminence.
- unique limited rotational opening is found only in

- in erect postural position & with a vertically placed
vertical column, continued rotational opening
movement would cause the mandible to impinge on
the vital sub-mandibular & retro-mandibular
structures of the neck.
Inner horizontal portion ;
- limits the posterior movement of the condyle &
disc.
- protects the retrodiscal tissues from trauma.
- also protects the lateral pterygoid muscle from
over-lengthening / extension
- trauma to the mandible – neck of the condyle will
fracture before the retrodiscal tissues are severed /
before the condyle enters the middle cranial fossa.

Accessory ligs ;
i) the sphenomandibular lig
ii) the stylomandibular lig
iii) the pterygomandibular raphe
iv) the retinacular lig

BIOMECHANICS OF TMJ –
Can be divided into two system:
1) One joint system;
Tissues surrounding the inferior synovial cavity
(condyle & the articular disc)
Only physiologic movement is rotation of the disc
on the articular surface of the condyle – condyle-
disc complex.
Responsible for rotational movement in the TMJ.

2) condyle-disc complex functioning against the
surface of mandibular fossa;
Free sliding movement possible, in the superior
cavity.
This movement occurs when the mandible is moved
forward – translation.
Articular disc is not a meniscus.
Meniscus – is a wedge shaped crescent of
fibrocartilage attached on one side to the articular
capsule & unattached on the other side,extending
freely into the joint spaces.
- functions passively to facilitate movement.

The articular surfaces of the joint is maintained by
constant activity of the muscles that pull across the
joint, primarily the elevators. (even in resting stage
in a mild tonus)
Increase in intra articular pressure holds the joint.
Width of the disc varies with the intra articular
pressure.
- low (closed rest position) – widens.
- high (clenced) – space narrows.

Posterior border of the articular disc – retrodiscal
tissues.
Opening of the mandible – the superior retrodiscal
tissue gets stretched, creating increased force to
retract the disc.
Mandible moves into full forward position & during
its return – retraction force of the sup. retrodiscal
tissue holds the disc rotated as far posteriorly on
the condyle as the width of the articular disc
permits.
The sup retrodiscal tissue – only structure capable
to retract the disc posteriorly on the condyle (wide

Anterior border of the disc –
attachment of the superior lateral pterygoid
muscle. (also attached to the neck of the condyle)
Helps in protraction of the disc, dual attachment
doesn’t allow the muscle to pull the disc through
the discal space
The inferior lat pterygoid when protract the condyle
forward, the superior fibers is inactive – disc is not
moved forward with the mandible.
The superior lat pterygoid is activated only in
conjunction with elevator muscles. (closure / power
strokes)

During translation, the combination of disc
morphology & interarticular pressure maintains the
condyle on the intermediate zone – disc is forced to
translate forward with the condyle.
When the morphology of the disc has been altered,
the ligamentous attachment of the disc affects joint
function.
Things to remember :
ligaments;
-do not actively participate in normal functioning of the
TMJ
-act as guide wires,restricting & permitting some
movements

Ligaments do not stretch (ability to return to its
original length)
- traction force- elongates, if elongates then often
the function is compromised.
Articular surfaces of the TMJs must remain in
constant contact (the elevators ; temporal,
masseter, & medial pterygoid)

Mandibular rest position :
-Physiologic rest position → muscle tonus of the
elevator muscles → myostatic reflex (affected by the
wt. of the mandible)
-Rest position → 1.3 – 3.0 mm of interocclusal
clearance (freeway space)
- Changes with head posture & muscle tonus.
-Varies with head position, total body posture,
functional activities, fatigue, time of day, age &
emotional tension.

VERTICAL DIMENSION OF OCCLUSION
Increase in VDO → increased activity in the elevator
muscles, with pain & resulting in dysfunction.
Akagawa et al;
- within interocclusal clearance displayed → transient
acute inflammation in the deep & superficial
masseter muscle.
- more than 1mm → early acute inflammation to
muscle fiber regeneration in the deep masseter, with
a lesser degree in superficial masseter & ant.
temporal muscle.
Carlson et al;
- VDO can be altered by using bite planes, without
affecting muscle tonus of the mandibular muscles.

Examination of TMJ in ORTHODONTIC CLINICS
Posture of the clinician & patient
Palpation – in closed, at rest & various open position
Deviation should be noted
Crepitus / abnormal sound
Palpation of the neck & sub mandibular area
Speech evaluation

Palpation in
•closed
•open
•wide open

Standards for TMJ evaluation:
pediatric dentistry 1989-
11(4);330
History ;
1) Does your child report any pain during chewing /
while opening the mouth wide?
2) Child report any discomfort in the jaws upon
awakening
3) Child complains of headache
4) Any history of trauma to the jaws or neck region?
5) History of allergies?
6) Jaw click / lock upon opening?

+ve history –
pain manifestation, stress, balanced diet,
sleeping posture
Clinical examination :
gentle & cautious palpation of muscles of
mastication.
- for trigger points
- rated, 0 – no pain ; 1- tenderness ; 2 –
definite pain ; 3 – evasive action.

Range of movement :
-maximum opening & lateral excursions
-widest opening – 40mm
-anterior bite depth – 34mm
-overbite – 6mm
Click :
-early, late, or both on opening.
Radiographic examination & advances :
- transcranial radiographs / tomograms
- MRI & arthrograms

Temporomandibular disorders in children:
Jeffrey
P.Okeson
Are TM disorders a problem in children ?
How TM disorders treated in children ?
Can early treatment prevent TM disorders ?

Are TM disorders a problem in children?
-epidemiologic studies – 10-18 yrs.
-studies place the findings into two categories
via;
a) symptoms b) signs
-common in young population – few complain
How are TM disorders treated in children?
-Ingerslev – conservative & reversible
-occlusal appliance - < 2 months

Two major categories :
a) masticatory
b) disc- interference / internal
dearangements
Can early treatment prevent TM
disorders?
-etiology is of paramount importance
-occlusal condition
-no scientific evidence

Prevalence of TMJ disorders in children
Eup J.orthod 14;152-161:1992
A longitudinal study,for the signs & symptoms of
CMD in 12-15 yr old individuals.
“during this period there is an increased prevalence
of S/S of CMD. In particular true for headache &
joint sounds.

Heritability of TMJ disorder signs & symptoms
J dent.res 79(8):1573-
1578,2000.
Genetic variance & environmental variances
This study results suggest that neither shared genes
nor the family environment accounts for much of
variance in TMJ related s/s & oral habits.
TMJ-pain was reported by 8.7% of the twins – Lipton
et al 1993.
Joint noises & locking in these twins were also about
as prevalent as in non-twin population.
Pain reporting in particular is influenced by mood,
stress, learned behaviors, physiological pain
threshold.- Mogil et al 1996.

They concluded that
i) Genetic factor do not influence joint disorders
manifesting pain.
or
ii) Pain perception factors are non-genetic, supported by
twin study of pain threshold – Mac Gregor et al
;1997.
So till date no study has substantial evidence of any
genetic relation of joint pain.

HARD TISSUE IMAGING:
•Panoramic projection
•Specialized TMJ radiography techniques:
•Trans cranial
•Trans pharyngeal
• Trans orbital
•Submento vertex (basal) projection
•Conventional tomography
•Computerized tomography (CT SCAN)
SOFT TISSUE IMAGIMG:
•Magnetic Resonance Imaging (MRI SCAN)
•Arthrography

TRANS PHARYNGEAL
TRANS ORBITAL
TRANS CRANIAL

OPG
CONVENTIONAL
TOMOGRAPHY

ARTHROGRAPHY
MAGNETIC RESONANCE
IMAGING

TMJ disorders – (intra capsular disorders)
Physical examination- inspection for the pattern & the
presence of noise / deviation on opening
Normal vertical opening – width of three fingers
Diff b/w maximal pain –free opening & maximal
opening with pain
Patient is asked to point the area of pain
Muscle of mastication palpated
Magnitude of opening ;
Maximal incisal opening of less than 20-25mm- muscle
spasm
Periauricular pain beginning at 25-30mm- TMJ capsulitis

Lateral movements ;
> 5mm –well functioning TMJ
normal lateral but painful vertical opening –muscle
spasm
1 min clench test :
- Tongue blade placed unilaterally on the posterior
teeth –if hyperactivity muscle – ipsilateral pain
- Capsulitis –pain on the contralateral side
- Placed bilaterally – if pain relieved – splint therapy.
TMJ noises :
-click – 2-3 trials indicates disc displacement
-during vertical & lateral motion.

TMJ tenderness ;
Patient open slightly bringing the condyle & disc from
under the zygomatic arch.
Retro discal area palpated – wide open mouth
The surface posterior to the condyle is pressed
Little fingers can be placed in the external auditory
canal
Lateral / posterior sensitivity – either capsulitis /
synovitis
or both.

Joint inflammation ;
-synovial, capsular / retrodiscal tissues – capsulitis or
synovitis
-due to infection, trauma, systemic diseases, articular
surface degeneration / disk displacement
-preauricular pain
-episodic swelling with occlusal changes can occur.
TMJ dislocation (open lock)
-subluxation
-painful
-jaw manipulation

Treatment of joint disorders –
Patient’s education
Pain free diet
Therapeutic exercises to rehabilitate the joint
Anti-inflammatory drugs &muscle relaxants
Physical therapy –
Heat / ice massage
Gentle range of motion exercises with in the pain
tolerance.( 6 times a day for 30-60 secs )
Joint shouldn’t hurt more than 10mins after exercise
Night time splint – reduces forces on the joint.

Night guard, controls parafunctional habit, temporary
stabilizes an uneven occlusion – allows the joint to
rest.
Should have a flat plane – opening the bite several
mm.
Soft night guard is given for children with developing
occlusion / mixed dentition.

Painful click – mandibular orthopedic repositioning
appliance

Extra capsular disorders -
Acute disorders :
Myositis- due to infection / injury
Protective muscle spinting – constriction of muscles
to avoid pain, pain in function
Myospasm (acute trismus) – involuntary, sudden,
tonic contraction of muscles

Chronic disorders :
Myofacial pain –
-most common in children
-jaw function aggravates headache.
-localized tender / trigger points (active / passive)
-tender spots may produce characteristic pattern of
referred pain.

-can be caused by postural problems, parafunctional
habits, psychological disorders, stress & trauma.
-pain is reduced / eliminated with anesthetic injection
into active trigger points, or a spray & stretch
procedure with fluormethane spray.
-long term - elimination of the contributing factor.
-analgesics, muscle relaxants, behaviour modification
& home rehabilitation & physical therapy.

Myofascial Pain – Dysfunction Syndrome
(MPDS) or
Temporomandibular Joint Pain Dysfunction
Syndrome or
Masticatory Myalgesia Syndrome
Schwartz in 1955.
Etiology :
- masticatory muscle spasm, due to muscular
overextension / muscular over contraction / muscle
fatigue.
- habits like clenching / grinding
- Laskin et al – the “psycho- physiologic theory”
- occlusal disharmony – altered chewing pattern.

c/f ;
- 80% - 90% - females (< 40yrs)
Four cardinal signs :
Pain
Muscle tenderness
Clicking / popping noise in the joint
Limitation of jaw motion (unilaterally / bilaterally)
Two typical –ve disease charecteristics
Absence of clinical, radiographic / biochemical
evidence of organic changes in the joint &
Lack of tenderness in the joint.

Treatment :
-conservative
-relief of emotional factors, faulty restorations &
appliances
-myotherapeutic exercises & physiotherapy
-drugs ; tranquilizers & muscle relaxants.

Correlation b/w occlusal characteristics & TMD
JCPD 24;229-
236 ;2000
Study showed a significant correlation b/w posterior
cross bite & TMD.
Egermark – Erikson –association b/w cross bite &
muscle tenderness.
1985 – Brandt compared cross bite to clicking,
significant.
Anterior openbite & edge to edge relationship with
TMD
- Egermark – Erikson –frontal openbite & crossbite
may predispose to mandibular dysfunction.
- Seligman & Pullinger –ant openbite was the variable
with the greatest influence on the presence of TMJ
tenderness.

They concluded that :
Significant correlation was found b/w TMD &
a) posterior crossbite
b) openbite & edge to edge occlusion
c) class III canine relationship.

Congenital abnormalities of TMJ:
Hemifacial microsomia (HFM) ;
-variable, progressive, & asymmetric craniofacial
deformity
-involves the skeletal, soft tissue & neuromuscular
components of the 1st &2nd pharyngeal arch
-Poswillo – hemorrhage from the developing stapedial
artery produces a hematoma in the area of the 1st &
2nd arches.
 Facial growth :
- asymmetric mandibular growth (unilateral / bilateral)
- growth is impaired with short, retrusive & narrow

Classification
Acc to skeletal defects
Type I – consists of a mini-mandible & TMJ
-all str. are present, normal in shape & location but
small
Type II – small mandible with a hypoplastic TMJ
i) type II A degree & location of
hypoplasia
ii) type II B
Type III – complete absence of ramus & TMJ.

Hemifacial microsomia

Acc to jaw motion & dev of muscles of mastication
Type I –
- both jaw motion, articular disc & muscles present.
Type IIA & B –
- hypoplastic, muscles of mastication & articular disc
- translatory & lateral movements are restricted.
Type III –
- lateral pterygoid & articular disc are absent
- moderately to severely hypoplastic temporalis, masseter &
medial pterygoid.
- doesn’t translate to affected side & move medially
towards the normal side

End stage of skeletal defect :
Short, medially, placed ramus & TMJ.
Mandible – flat in contour & chin point deviated
towards the effected side.
Short midface – resulting in a canted occlusal plane
( ↓ distance b/w the infraorbital rim, piriform
aperature, & maxillary alveolus)
Flat zygomatic bone, orbit sometimes is inferiorly
present

 Acc to soft tissue defects:
Mild ;
- minimal subcutaneous & muscle hypoplasia.
- absence / slight macrostomia
- mild auricular defect (pre-auricular tags)
Severe ;
- severe hyploplasia- subcutaneous & muscles
- facial clefts
- macrostomia
- neuromuscular weakness
Moderate

 Acc to ear anomaly ( Meurman)
Grade I ; mild hypoplasia & cupping
Grade II ; absence of external auditory canal &
hypoplasia of conchae
Grade III ; auricle is absent, anteriorly & inferiorly
displaced lobule.
Conductive hearing loss – hypoplasia of ear
ossicles.

OMENS classification : Vento et al
O – Orbit
M – Mandible (& TMJ)
E – Ear
N – Nerves
S – Soft tissues

Scoring ;
Orbit – 0 -normal Mandible – 0 -normal
1 -abnormal size 1 -type
I
2 -position 2A -
type II A
3 -both 2B -
type II B
3 -
type III
Ears – Meurman’s system
Nerves – Facial defect Soft tissues – 0-
normal

Treacher Collins syndrome : mandibular dysostosis
• Autosomal dominant
• Due to an insult to the neural crest cells (4-6 weeks of
embryogenesis)
c/f ;
Treacher collin (1900)
• anomalies are bilateral & symmetrical
• Antimongoloid (downward) cant of the palpebral
fissure
• Colomba at the junction of outer & middle 3rd of lower
eyelids
• Absence of eyelashes
• Ears are low set & hypoplastic

• Nose is large, the zygomatic bones & arches are
hypoplastic or missing
• Frontozygomatic suture is inferiorly displaced –orbits
are “tear drop” in shape.

Bilateral facial microsomia :
• They have similar skeletal deformities
• Do not show charecteristic soft tissue defects around
the eyelids.
• Asymmetrical defect
• No inheritance pattern

Developmental disturbances :
Aplasia of the condyle –
a) unilateral
b) bilateral
c/f –
-anatomically related defects ; defective or absent
external ear, an underdeveloped ramus or
macrostomia.
-facial assymetry
Treatment –
-osteoplasty (if derangement is severe)
-orthodontic appliance
-cosmetic correction – correcting facial deformity.

Hypoplasia of condyle
a) congenital
b) acquired
Congenital hypoplasia : (idopathic)
Unilateral
Bilateral
Acquired hypoplasia :
Forcep delivery
External trauma
X-ray radiation for local treatment of skin lesions
Infections
Endocrine or vitamin derangement

c/f –
a) depends on its effect on one / both condyle
b) degree of malformation
c) age of the patient
d) duration of injury & its severity
Unilateral (common) –
Facial asymmetry
Limited lateral excursion
Mandibular midline shift during opening & closing
due to lack of downward & forward growth of the body
of mandible.

Treatment & prognosis :
-poor as there no means to stimulate growth locally
-cartilage or bone transplants
-costochondral grafts to mimic condylar head
&
- metatarsal grafts has shown growth
potential

Hyperplasia of the mandibular condyle
-unilateral in most cases resembling an osteoma or
chondroma
c/f –
- pt exhibits a unilateral ,slow progressive elongation of
the face with deviation of the chin away from affected
side.
-condyle evident clinically & palpable
-striking radiographically appearance in AP& lateral
view.
-may or maynot be painful
-severe malocclusion.
Treatment -
- resection of the condyle

Ankylosis (hypomobility)
Etiology:Straith & Lewis
Abnormal IU life
Birth injury
Trauma to the chin
Malunion of condylar #
Loss of tissue with scarring
Congenital syphilis
Primary inflammation of the joint
Secondary inflammation to a blood stream disease
Metastatic malignancies
Inflammation secondary to radiation therapy

c/f –
-any age group
-before age of 10 yrs
-both sexes affected
-difficult in opening mouth.
Complete ankylosis;
-bony fusion with limited motion
-associated with facial deformity
a) Unilateral ankylosis-
-the chin is displaced laterally & backward on the
affected side

b) bilateral ankylosis ;
-maxillary incisors manifests over jet due to failure of
the mandibular growth.
TMJ ankylosis :
a) intra-articular
b) extra- articular
Intra-articular – joint undergoes progressive destruction
of the articular disc with flattening of the mandibular
fossa.
Extra-articular – splinting of the TMJ by a fibrous / bony
mass external to the joint proper (as in infections)
Treatment is surgical (osteotomy)

Injuries to the articular disc
Etiology :
Malocclusion
Episode of acute trauma to the jaw
Inflammatory conditions
c/f :
Common in female
Young adults & persons > 40yrs
Characterized by,
- pain
- snapping / clicking & crepitation in the joint area
- transient / prolonged locking of jaw

s/s ;
-pt.may complain of dull pain in & around the ear or on
the side of the jaw, with tinnitus, & dysesthesia of the
tongue reported in some cases.
Diagnosis -
radiographs in both open & closed position.
Treatment –
-immobilization of jaws- severe pain
-malocclusion correction
-meniscetomy

Inflammatory disturbances of the
TMJ
Arthritis / inflammation of the TMJ :
Due to infection
Rheumatoid
Osteoarthritis / degenerative joint disease.
Due to specific infection ;
- resulting from gonococci, streptococci, staphylococci,
pneumococci & tubercle bacillus (polyarticular
involvement)
-gonococci effects the joint – Markowitz & Gerry.

c/f :
-severe pain with tenderness to palpation
-motion is severely limited
-healing results in ankylosis (osseous or fibrous)
Treatment :
-antibiotics
-acute phase –less deforming
-chronic phase / advanced stage – menisectomy or
condylectomy

Rheumatoid arthritis :
Etiology :
-idiopathic
-early adult life
-female : male -2 : 1
c/f :
-polyarticular & bilateral
-episodic exacerbations & remissions
-early stages : low fever, loss of wt & fatigability.
-joint are swollen, pain & stiffness

Still’s disease :
-may cause a malocclusion of the class II div I type,
with protrusion of the maxillary incisors & an
anterior openbite.
-radiograph reveal flattening & stunting of the
condyles & haziness about the joint indicative of
periarticular fibrosis.
Treatment :
-administration of ACTH / cortison
-limitation of motion – condylectomy .

“ The clinician who only looks
at occlusion is missing as
much as the clinician who
never looks at occlusion. ”
OKESON

References :
Management of Temporomandibular Disorders &
occlusion -JEFFREY P.OKESON
Diseases of the temporomandibular apparatus
- DOUGLAS H. MORGAN
Pediatric oral & maxillofacial surgery
- L B.KABAN
Oral anatomy, histology & embryology
- BERKOVITZ
DCNA –vol.27,no.3,july 1983
Bell’s orofacial pain -5th ed.

•Orthodontics & the temperomandibular joint: where
are we? Part 1: orthodontic treatment and TMJ
disorders. The Angle Orthodontist:vol. 68, no.4 -295- 304
•Orthodontics & the temperomandibular joint: where
are we? Part 2:functional occlusion,malocclusion,&
TMD. The Angle Orthodontist:vol. 68, no.4 -305- 318.
•Prevalence of TMJ disorders in children :Eup J.orthod
14;152-161:1992
•Heritability of TMJ disorder signs & symptoms:
J dent.Res 79(8):1573-1578,2000.
•Standards for TMJ evaluation: pediatric dentistry 1989-
11(4);330

Temporo Mandibular joint (TMJ) importance in orthodontic treatment /certified fixed orthodontic courses by Indian dental academy

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