Tmj ....a basic review /certified fixed orthodontic courses by Indian dental academy

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

•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 jawarticulation 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 Reptileenlarged 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
6th arch

No Names

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.

Horizontal section of developing mandible 8th 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

 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.

14 weeks of Human
Fetus
Parietal
bone
Occipital

Frontal bone
Squamous
Part
Secondary
Secondary
condylar
coronoid cartilage
Cartilage
Ramus


Maxilla

 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, “ Here in 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,

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
- LAYERS ARE
3
SEPERATED BY AN RAMUS AND
CORONOID
www.indiandentalacademy.com NERVE
ARTERY & A

TEMPORALIS
 FAN shaped muscle.
Fills the Temporal Fossa.

MUSCLE

TEMPORALIS

ORIGIN

FIBERS

CONVERGE &
PASSES
THROUGH GAP
DEEP TO ZYG.
ARCH

TEMPORAL
BONE AND
FASCIA

INSERTION

MARGIN & DEEP
SURFACE OF
CORONOID
- ANT. BORDERS
OF RAMUS OF
MAND.
-

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

SUPPLIES:
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.

LATERAL
PTERYGOID

LAT. PTERYGOID.
(II PART OF
MAXILLARY A.)

MEDIAL
PTERYGOID

MED. PTERGOID.
(II PART OF
MAXILLARY A.)

PTERYGOID
VENOUS PLEXUS

DEEP TEMPORAL
(BR.OF ANT.
DIV.OFMAND.NR)

MAXILLARY VEIN

LAT. PTERYGOID
(BR.OF ANT. DIV.OF
MAND.NR)

RETROMANDIBULAR
VEIN

MED. PTERYGOID
(BR. OF MAIN
TRUNK OF MAND.
NR.)


ELEVATION
MASSETER
MEDIAL PTERYGOID

TEMPORALIS

RETRACTION

PROTRACTION

DIGASTRIC
GENIOHYOID

LATERAL PTERYGOID
MYLOHYOID

DEPRESSION


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
I- mental tubercle
I- digastric fossa

 Condyle
LP-

lateral pole

MP-

medial pole

pterygoid
fovea


1450



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

Total medio-lateral length – 15 – 20 mm
The anteroposterior width – 8 – 10 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

 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

A – head of adult condyle
centre
B – lower part of intraarticular
periphery
disc
& lack of
bone

A – collagen fibers at the
B – regularly aligned at
C – larger marrow spaces


a layer of compact

 Histology of
articular surfaceA – 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.
IC- inferior joint cavity
muscles
IRL- inferior retrodiscal lamina
SC- superior joint cavity
pterygoid

AS- articular surface
ILP- inferior lateral pterygoid
RT- retrodiscal tissues
SLP- superior lateral
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)
PACINI
GOLGI
FREE

Dynamic &
static balance
(capsule)

Dynamic
Movement
(mechanoreception) accelerator
(capsule)
Static
Protection
(mechanoreception) (ligament)
Pain
Protection
(nociception)
(joint)

 Vascularization –
- predominantly ;
artery
artery
artery

i) from posterior- superficial temporal

ii) from anterior- middle meningeal
iii) from inferior- internal maxillary
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

 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
 IHPInner horizontal
portion
 OOPOuter 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 & retromandibular 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

 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

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)www.indiandentalacademy.com

 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
-restrict joint movements both by mechanical &
through neuromuscular reflex activity.

 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

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;152161:1992
 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



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 20-25mmmuscle 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

 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

 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.

“ 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 1989www.indiandentalacademy.com
11(4);330

Thank you
For more details please visit


Tmj ....a basic review /certified fixed orthodontic courses by Indian dental academy

Empfohlen

Empfohlen

Weitere ähnliche Inhalte

Was ist angesagt?

Was ist angesagt? (20)

Andere mochten auch

Andere mochten auch (12)

Ähnlich wie Tmj ....a basic review /certified fixed orthodontic courses by Indian dental academy

Ähnlich wie Tmj ....a basic review /certified fixed orthodontic courses by Indian dental academy (20)

Mehr von Indian dental academy

Mehr von Indian dental academy (20)

Kürzlich hochgeladen

Kürzlich hochgeladen (20)

Tmj ....a basic review /certified fixed orthodontic courses by Indian dental academy

Hinweis der Redaktion