Complete summary of anatomy of tmj, mandibular movements and its role in prosthodontics. Muscles of mastication, biomechanics of tmj. Dentists must assess the oral function of patients prior to any treatment, since mastication is the most important oral function and it is closely related to TMJ. Proper knowledge of its anatomy & function are keys for successful PROSTHODONTIC treatment The articulation of the condylar process of the mandible and the intra-articular disc with the mandibular fossa of the squamous portion of the temporal bone; a diarthrodial, sliding hinge (ginglymus) joint; movement in the upper joint compartment is mostly translational, whereas that in the lower joint compartment is mostly rotational; the joint connects the mandibular condyle to the articular fossa of the temporal bone with the TEMPOROMANDIBULAR JOINT ARTICULAR DISC interposed . - GPT 9

1. ANATOMY OF TMJ & ROLE
IN PROSTHODONTICS
Presented by
Baishali Ghosh
1ST Year PGT
Department of Prosthodontics,
Crown & Bridge.
1
UNDER THE ABLE GUIDANCE OF:-
DR.(PROF) JAYANTA
BHATTACHARYA
[HOD & PRINCIPAL]
DR.(PROF) SAMIRAN DAS
DR.(PROF) SOUMITRA GHOSH
DR.(PROF) PREETI GOEL
DR.SAYAN MAJUMDAR
DR. SUBHABRATA ROY

2. CONTENT
1)DEFINITION
2)PECULIARITY OF TMJ
3)DEVELOPMENT OF TMJ
4)ANATOMY OF TMJ
5)MANDIBULAR MOVEMENTS
6)PROSTHODONTIC IMPLICATIONS
2

3. 3
BONE
CONDYLAR PROCESS
OF THE MANDIBLE
MANDIBULAR FOSSA OF THE
SQUAMOUS PORTION OF
TEMPORAL BONE.
INTRA-ARTICULAR
DISC
SYNOVIA
L
JOINT
DIARTHROIDAL
GINGLYMOIDAL
MOVEMEN
T
UPPER
COMPARTMENT
LOWER
COMPARTMENT
TRANSLATION
ROTATION
It provides for hinging movement in
one plane
it also provides for gliding movements
Thearticulationofthecondylarprocess
ofthemandibleandtheintra-articular
discwiththe mandibularfossa ofthe
squamousportion ofthetemporalbone;a
diarthrodial,slidinghinge(ginglymus)
joint;movementintheupperjoint
compartmentismostlytranslational,
whereasthatinthelowerjoint
compartmentismostlyrotational;the
jointconnectsthemandibularcondyleto
thearticularfossa ofthetemporalbone
withtheTEMPOROMANDIBULARJOINT
ARTICULARDISCinterposed .
- GPT9
TEMPOROMANDIBULAR JOINT

4. PECULIARITY OF TMJ
4
1) ARTICULATING
SURFACE
PECULIARITY:-
Mostly the articular surfaces of joints
are covered by:-
HYALINE CARTILAGE
Articular surfaces of TMJ are covered by
FIBROCARTILAGE.
a)Greater repair capacity.
b)Less susceptible to degeneration.

5. 2. COMPOUND JOINT
- JOINT FORMED BY 3 BONES
GLENOID
FOSSA OF
TEMPORAL
BONE
ARTICULAR DISC
•NON OSSIFIED BONE
•PECULIARITY- Though
articular disc is non ossified,
since it acts as a 3rd bone ,
TMJ is considered as
COMPOUND JOINT
CONDYLAR
HEAD OF
MANDIBLE
5

6. 3. DEVELOPMENT
•  Compared to other diarthrodial joint TMJ is the
last to develop.
•  Other joints develop from single blastema
• TMJ develops from 2 blastemas
6

7. 7

8. BLASTEMIC STAGE:-
(WEEK 7-8)
8
WEEK-
7
Mesenchymalcondensation observedinTMJ regionupon thefuture
mandibular ramus=CONDYLARBLASTEMA
Thecondylarblastema isassociatedwith themassetericand
auriculotemporalnerves,whichrunsbetweenthefuture condyleand
Meckel’scartilage.
Amesenchymalcondensationappearedcraniolaterallytothecondylar
blastemathatformedthe TEMPORALBLASTEMA
WEEK-
8
Intramembranousossification ofthezygomatic processofthesquamous partofthetemporalbonebegan
Intramembranousossification oftheramus ofthemandiblereachingthebaseofthefuturecondyle
Craniolaterallyto thefuturecondylethereisamesenchymalcondensationthat formstheanlageofthe ARTICULARDISC
Thelateralpterygoid muscleinsertedinthemedialportion ofthecondylar-discalcomplex.

9. CAVITATION STAGE:- (WEEK 9-11)
9
WEEK 9 &10
Condylarchondrificationbeganinthe centreofcondylarblastema
Initialformation ofthe INFERIORJOINTCAVITY:-
Smallspacesorcleftsappearedbetweentheanlageofthearticular discand themandibular
condyle.
WEEK 11
SUPERIORJOINTCAVITY:-
Theorganization ofthesuperiorjointcavitybeganbetweenthezygomatic processofthe
squamous partofthetemporalboneandthearticular disc
Thesuperiorfasciclesofthelateralpterygoid muscleinsertedinto thearticular discand
mandibularcondyle
Theinferiorfasciclesofthelateralpterygoid muscleinsertedintothemandibular condyle
Articular surfaceofthesquamous partofthetemporalbone haveaflatsurface.

10. MATURATION STAGE (WEEK 12 ONWARDS):-
10
Byweek13:-
Thejointsurfaceof thesquamous partofthetemporalboneacquiresaconcavemorphology.
Duringweek16:-
Thenarrowcentralportion ofthearticular discappears avascular although smallvessels
canbeobservedontheperipheralportions
Duringweek17:-
Jointcapsuledevelops.

11. ANATOMY OF
TEMPOROMANDIBULAR
JOINT
11
BONY
COMPONENT
LIGAMENTS MUSCULAR
COMPONENT
A.GLENOID
FOSSA OF
TEMPORAL
BONE
B. ARTICULAR
EMINENCE
C.
MANDIBULAR
CONDYLE
A.
COLLATERAL
(DISCAL)
LIGAMENT
B. CAPSULAR
LIGAMENT
C.
TEMPEROMAN
DIBULAR
LIGAMENT
SPHENOMANDIBULAR
LIGAMENT
STYLOMANDIBULAR
LIGAMENT
MASSETER
TEMPORALIS
MEDIAL PTERYGOID
LATERAL PTERYGOID
BONY
COMPONENT
LIGAMENTS MUSCLE

12. BONY COMPONENT
12
ARTICULAR
EMINENCE
25˚
a)Angulation of
articular eminence with
the occlusal plane.= 25˚
POSTGLENOID
TUBERCLE
ANTERIOR
ARTICULAR
AREA OF FOSSA
POSTERIOR NON-
ARTICULAR
AREA OF FOSSA
It is formed entirely by the squamous portion
of the temporal bone.
Separated by
SQUAMOTYMPAN
IC FISSURE.
a) POSTGLENOID TUBERCLE b) SQUAMOTYMPANIC
FISSURE
It is formed entirely by the tympanic portion of the
temporal bone

13. MANDIBULAR CONDYLE
13
30˚
The condylar head tilted forwards on
the neck at an angle of 30˚
Condylar
head
articulates
with disc on
its anterior
and superior
Anterior view of mandible:-
Medial & Lateral projections are
present.
These projections are called POLES.
Prominrnce
Medial pole > Lateral pole
Dimensions
Mediolateral length= 18-23mm
Anteroposterior width= 8-10mm

14. 14
ARTICULAR DISC
DEFINITION:-
The articular disc is a fibrous connective tissue disc located
between the articulating surfaces of the mandibular condyle
and temporal bone.- GPT-9
FUNCTION:-
a)Accommodate hinge as well as gliding motion
b)Reduce wear
c)Aids in lubrication
Articular disc is divided into 3 parts:-
a) Anterior border= thicker part ( but less than posterior
border)
b) Intermediate zone= thinnest central area
c) Posterior border= thickest part

15. 15
ARTICULAR DISC :-ATTACHMENTS
SUPERIOR RETRODISCAL
LAMINA
Lamina consistes of connective
tissue mainly composed of
ELASTIC FIBERS.
Attaches the articular disc
posteriorly to TYMPANIC PLATE.
RETRODISCAL TISSUE
Highly vascular.
Only portion of the articular disc
that is innervated
INFERIOR RETRODISCAL
LAMINA
Lamina consistes of
COLLAGENOUS FIBERS.
Attaches the articular disc to the
posterior margin of articular
surface of condyle
POSTERIOR
ATTACHMENTS:- ANTERIOR ATTACHMENTS:-
The Superior & Inferior
attachments of the anterior
region of the disc are to the
capsular ligament, which
surrounds most of the joint
Anteriorly, between the
attachments of the capsular
ligament, the disc is also
attached by fibers to the
superior lateral pterygoid
muscle.
SUPERIOR ATTACHMENT=
Attaches to the articular surface
of the Temporal bone
INFERIOR ATTACHMENT=
Attaches to the articular surface
of condyle.

16. 16
ARTICULAR DISC:-
HISTOLOGY
ARTICULAR ZONE
LOCATION= Aadjacent to the joint cavity, forms the
outermost functional surface.
TISSUE= Collagen type I fibres aligned parallel to the
articular surface
ADVANTAGE OF FIBROUS CONNECTIVE TISSUE=
a)Less susceptible than hyaline cartilage to aging
b)It also has a much better ability to repair itself than hyaline
cartilage.
PROLIFERATIVE ZONE
CONSTITUENTS= Cellular
Undifferentiated Mesenchymal tissue.
FUNCTION=Responsible for the proliferation of articular
cartilage in response to functional demands placed on the
articular surfaces during loading.
FIBROCARTILAGINOUS ZONE
The collagen fibrils type II arranged in crossing
pattern.
Offers resistance against compressive & lateral forces
due to its three dimensional network.
CALCIFIED CARTILAGE ZONE
COMPOSITION= Chondrocyte & Chondroblast.
Chondrocyte become osteocyte in this
region
It is an active zone for Remodeling activity.

17. 17
SYNOVIAL JOINT
Q) WHY IS TMJ REFERRED TO AS SYNOVIAL JOINT?
ANS SYNOVIAL LINING
Intenal surface of the cavities are surrounded by ENDOTHELIAL CELLS which forms Synovial
lining.
LOCATION OF SYNOVIAL FRINGE
Anterior border of Retrodiscal tissue.
Both the synovial lining and synovial fringe produce synovial fluid which fills the cavity,
(upper joint= 1.2ml of synovial fluid approx. lower joint=0.9 ml of synovial fluid approx.)
hence TMJ is referred to as Synovial joint.
Q) PURPOSE OF SYNOVIAL FLUID?
ANS a) Lubricant between articular surfaces.
b) Acts as a medium for providing metabolic requirement to tissue since the articular surfaces of
the joint
are non-vascular.

18. 18
LUBRICATION MECHANISM
BOUNDARY LUBRICATION WEEPING LUBRICATION
Joint that
is
lubricated
Moving joint. Compressed joint
Mechanism
Part in
Lubrication
Primary mechanism of joint
lubrication.
Plays a small role in
lubrication.
Joint is moved
Synovial fluid forced
from one area of cavity
into another.
Fluid located in border
or recess is forced on
articulating surface
Thereby providing
lubrication
Compressive forces applied on
joint during function.
Articulating surfaces comes
closer
These forces drive a small amount of synovial
fluid in & out of articular tissue.
Thereby providing lubrication
between articular tissue

19. 19
LIGAMENTS
KEY FACTORS ABOUT
LIGAMENT:-
a) Ligaments are made of
collagenous connective
tissue fibers that have
particular length. They do
not stretch.
b) They do not enter actively
into joint function but act as
passive restraining device to
limit & restrict border
movement.

20. 20
PRIMARY
LIGAMENT
CAPSULAR LIGAMENT
SUPERIOR ATTACHMENT:-
a) Temporal bone along the borders
of the articular surface of mandibular
fossa
b)Articular Eminence
INFERIOR ATTACHMENT:-
Neck of the condyle
FUNCTION:-
a) Resist medial, lateral or inferior forces that tend to
separate or dislocate articular surfaces.
b) Retain Synovial fluid
c) Proprioreception
LATERAL PTERYGOID MUSCLE
passes through the orifice present in the
anterior border of the ligament
PATHOLOGY:-
Area of relative weakness in the ligament &
possible site of intra articular tissue herniation.

21. 21
COLLATERAL (DISCAL)
LIGAMENT
MEDIAL DISCAL
LIGAMENT
Attaches medial edge of the
disc to medial pole of condyle
LATERAL DISCAL
LIGAMENT
Attaches lateral edge of the
disc to lateral pole of
condyle
FUNCTION:-
a)Allow the disc to move passively with the condyle as it glides Antero posteriorly.
b)Permit the disc to be rotated Antero posteriorly on the articular surface of condyle.
c) RESPONSIBLE FOR THE HINGING MOVEMENT BETWEEN THE CONDYLE & THE
ARTICULAR DISC

22. 22
TEMPEROMANDIBULAR LIGAMENT
OUTER OBLIQUE
PORTION
INNER HORIZONTAL
PORTION
EXTENSION
From outer surface of articular
tubercle & zygomatic process to
lateal pole of condyle & posterior
portion of articular disc .
From outer surface of articular
tubercle & zygomatic process to
neck of condyle.
FUNCTION Resist excessive dropping of
condyle
Limiting the extent of mouth
opening
Limits the posterior movement of
condyle & disc

23. 23
ACCESSORY LIGAMENT
STYLOMANDIBULAR
LIGAMENT
SPHENOMANDIBULA
R LIGAMENT
Extends from spine
of sphenoid to lingula
of mandible.
Extends from styloid
process to ramus of
mandible.
FUNCTION:-
Limits excessive
protrusive motion of
mandible

24. 24

25. 25
INSERTION:-
ORIGIN:-
a) Maxillary processofthezygomatic bone.
b) Anteriortwo-thirds oftheinferiorborderofthe
zygomatic arch.
SUPERFICIAL
FIBERS
a) Medialaspectoftheanteriortwo-thirds ofthe
zygomatic arch.
b) Thelowerborderoftheposterior thirdof
zygomatic arch.
MIDDLE
FIBERS
Deeplayerarisesfromthedeepsurfaceofthe
zygomatic arch DEEP FIBERS
Theangleandlowerposterior halfofthe
lateralsurfaceofthemandibularramus
10˚
˚

26. 26
a)ELEVATION of mandible.
b)SUPERFICIAL FIBERS:-
 Aid in PROTRUSION of
mandible.
c)DEEP FIBERS:-
When the mandible is protruded
and biting force is applied, the fibers
of the deep portion stabilize the
condyle against the articular
eminence

27. 27
ORIGIN:-
a) Arises fromthewhole ofthe
temporalfossa upto the
inferiortemporal line.
b) Fromthedeep surfaceofthe
temporalfascia.Its fibres
converge
INSERTION:-
a) Coronoidprocess
b) Anteriorborderof
themandibular
ramusalmostupto
thethird molartooth

28. 28
CONTRACTIONAS ASINGLEMUSCLE
POSTERIO
R
FIBERS
CONTRACTION OF PORTIONS OF MUSCLE
ANTERIOR
FIBERS
MIDDLE
FIBERS
ELEVATION OF
Mandible is raised
vertically.
ELEVATE & RETRUDE
mandible
RETRUDE mandible

29. 29
ORIGIN INSERTION:-
DEEP
HEAD
Arisesfromthemedialsurfaceof
thelateralpterygoid plateofthe
sphenoidbone
SUPERFICIAL
HEAD
a)Maxillary tuberosity
b)Pyramidal processofthepalatine bone
Posteroinferiorpartofthemedial
surfaceoftheramusandangleof
themandible
30˚

30. 30
A)CONTRACTION=mandibleis
ELEVATED.
B)PROTRUDESthemandible.
C)UNILATERALCONTRACTION
MEDIOTRUSIVEmotionofmandible

31. 31
ORIGIN INSERTION:-
SUPERIOR HEAD
Infratemporalsurfaceof the
greaterwingofsphenoidbone
INFERIOR HEAD
Lateralsurfaceof Lateral
pterygoidplate
Insertedintoadepression
onthefrontoftheneckof
themandible(the
pterygoidfovea).

32. 32
INFERIOR LATERAL
PTERYGOID
BILATERAL CONTRACTION:-
Condylesarepulledforward
downtheArticulareminence
&themandibleisprotruded.
UNILATERAL
CONTRACTION:-
Mediotrusivemovementof
condyle&causesalateral
movementofmandibletothe
oppositeside
SUPERIOR
LATERAL
PTERYGOID
POWERSTROKE
referstomovements
involvingclosureofthe
mandibleagainst
resistance,asin
chewingorclenching
theteeth.
SuperiorLateral
Pterygoidismainly
responsibleforit

33. 33
MASSETER
a)Maxillaryartery
b)Facial artery
c)Superficialtemporal
artery
Massetericbranchof
anteriortrunkofmandibular
nerve
TEMPORALIS
DeepTemporal branchesof
2nd partofMaxillary artery
DeepTemporal branchof
anteriortrunkofMandibular
nerve
MEDIAL
PTERYGOID
Pterygoidbranchesof
Maxillaryartery
Medialpterygoid branchof
mandibular nerve
LATERAL
PTERYGOID
a)Pterygoidbranchof
MAXILLARY ARTERY
b)Ascending Palatinebranch
ofFACIALARTERY
a)Superiorhead&Lateral
partof Inferior
headBUCCAL NERVE
B)Medial part ofInferior
headMANDIBULAR NERVE

34. 34

35. 35
ARTERIES:-
Laterally SUPERFICIAL TEMPORAL
ARTERY
Medially MAXILLARY ARTERY
NERVE:-
AURICULOTEMPORAL NERVE
MASSETERIC NERVE

36. 36

37. MANDIBULAR
MOVEMENTS
37
TYPES OF MOVEMENT
a)ROTATION
b)TRANSLATION
BORDER MOVEMENTS
a) SAGITTAL PLANE BORDER
b)HORIZONTAL PLANE BORDER
c)FRONTAL(VERTICAL) PLANE
BORDER

38. BIOMECHANICS OF THE TMJ
INFERIOR SYNOVIAL CAVITY
OR
CONDYLE-DISC COMPLEX
Disc is tightly bound
to the condyle by the
medial and lateral
discal ligament
Hence the only
physiological
movement that can
occur here is
ROTATION
38
SUPERIOR
SYNOVIAL
CAVITY
Condyle-Disc
complex is pressed
against Mandibular
fossa
Disc is not tightly
attached to the
articular fossa
Free sliding movement occurs
between articular disc and
mandibular fossa - TRANSLATION

39. 39

40. 40

41. 41

42. 42

43. 43

44. 44

45. 45
MOVEMEN
T
ROTATION
The process of
turning around an
axis: movement of a
body about its axis
TRANSLATION
Movement in which
every point of the
moving object
simultaneously has
the same direction
and velocity.
HORIZONTAL AXIS
FRONTAL(VERTICAL)
AXIS
SAGITTAL AXIS
HINGE MOVEMENT.
Only mandibular position wherein there is a
PURE rotational movement.
Only opening and closing motion takes place

46. 46
The axis varies during
different phases of
protrusive movement
Initial mouth opening at
the head of the condyle
Later stages of mouth
opening axis passes through
the mandibular foramen
TERMINAL HINGE AXIS:-
When the condyles are in the most superior position in the articular fossa & the mouth is
purely rotated open, the axis around which movement occurs is called terminal hinge axis

47. 47
BALANCING SIDE
WORKING SIDE
Condyle moves
downward and medially
along the slope of
ENTOGLENOID
PROCESS.
Condyle tends to move
in upward and lateral
direction.
SAGGITAL AXIS OF ROTATION:- Mandibular movement around
sagittal axis occurs when one condyle moves inferiorly while the other remains in the
terminal hinge axis

48. 48
WORKING SIDE BALANCING SIDE
Remains in the
terminal hinge
axis
Moves anterior
to the terminal
hinge axis.
FRONTAL (VERTICAL) AXIS

49. 49
SAGGITAL BORDER MOVEMENT

50. SAGGITAL BORDER MOVEMENT
50
Condyles are at the
superior most
position in articular
fossa i.e. CENTRIC
RELATION
HORIZONTAL
AXIS=at the
condyles.
Pure rotation
takes place
Pure rotation takes
place till the
distance of 20 to 25
mm between incisal
edges of maxillary
& mandibular
incisors
On further opening
Temporomandibula
r ligament tightens
& translation
begins
HORIZONTAL AXIS= rami
of mandible( at the point of
attachment of
Sphenomandibular
ligament.
Condyles
move= in
anterior &
inferior
direction
Anterior
portion of
mandible move
in inferior &
posterior
direction.
At maximum
opening of 40-60
mm CAPSULAR
LIGAMENT
prevent further
motion of condyle
POSTERIOR
OPENING
BORDER
MOVEMEN
T
2ND
STAGE
1ST STAGE
TERMINAL HINGE AXIS
ANTERIOR
OPENING
BORDER
MOVEMENT
Maximally opened
mandible
INFERIOR LATERAL
PTERYGOID contraction
to produce anterior
closing movement
As closure occurs,
STYLOMANDIBULAR
LIGAMENT contraction
occurs to pull condyles
posteriorly from most
protrusive position

51. 51
SUPERIOR
CONTACT
BORDER
MOVEMENT
CENTRIC
RELATION
initial tooth contact
mesial inclines of
maxillary tooth &
distal inclines of
mandibular tooth.
CRICP
Distance
traversed= 1-
1.25mm
Incisal edges of
mandibular anteriors
move antero-inferiorly
along the lingual slope of
maxillary anteriors.
This motion continues till
edge to edge relation is
achieved.
Movement continues till
incisal edges of
mandibular anterior
teeth pass beyong
maxillary anterior teeth
edges.
Mandible then moves
posteriorly till the
posterior teeth come in
contact
Continued forward movement determined by
posterior tooth surface It continues till
maximum protrusive position reached as is
allowed by ligaments.
It then joins the superior
most point of anterior
opening border movement

52. 52
HORIZONTAL PLANE BORDER
MOVEMENT

53. 53
RIGHT CONDYLE/ORBITING
CONDYLE/NONWORKING
CONDYLE
LEFT
CONDYLE/ROTATING
CONDYLE/WORKING
CONDYLE
Contraction of right
inferior lateral
pterygoid muscle
Right condyle move
anteriorly & medially
from CR position
Relaxation of left
inferior lateral
pterygoid muscle
Left condyle will
remain in CR
position.
RIGHT CONDYLE/ORBITING
CONDYLE/NONWORKING
CONDYLE
LEFT
CONDYLE/ROTATING
CONDYLE/WORKING
CONDYLE
Already in
maximum
anterior position
Contraction of left
inferior lateral
pterygoid muscle
Left condyle move
anteriorly & medially
from CR position
1) LEFT LATERAL BORDER
2) CONTINUED LEFT
LATERAL BORDER WITH
PROTRUSION
3) RIGHT LATERAL
BORDER
4) CONTINUED RIGHT
LATERAL BORDER WITH
PROTRUSION

54. FRONTAL PLANE BORDER MOVEMENT
54

55. 55
1) LEFT LATERAL
SUPERIOR
BORDER
2) LEFT LATERAL
OPENING
BORDER
3) RIGHT LATERAL
SUPERIOR
BORDER
4) RIGHT LATERAL
OPENING
BORDER

56. ENVELOPE OF MOTION
56
CR: centric relation,
CO: centric occlusion,
MRL: maximum right lateral position,
MLL: maximum left lateral position,
MP: maximum protrusion,
ER: edge-edge relationship,
MMO: maximum mouth opening,
THA: true hinge axis,
RAT: rotation after translation

57. 57

58. CENTRIC RELATION
58
A maxillomandibular relationship, independent of tooth contact, in
which the condyles articulate in the anterior-superior position against
the posterior slopes of the articular eminences; in this position, the
mandible is restricted to a purely rotary movement; from this
unstrained, physiologic, maxillomandibular relationship, the patient
can make vertical, lateral or protrusive movements; it is a clinically
useful, repeatable reference position. – GPT 9

59. HOW DOES THE MANDIBLE GOES INTO
CENTRIC RELATION?
59
The triad of strong elevator
muscles pulls the condyle-
disk assemblies up the
posterior slopes of the
articulareminence.
The inferior lateral
pterygoid muscles
release and stay
released through
complete closure
Complete
seating of
condyle in
superior most
position.
MASSETE
R
MEDIAL
PTERYGOID
TEMPORALI
S

60. CONDYLAR GUIDANCE
60
Mandibular guidance generated by the condyle and articular disc
traversing the contour of the articular eminence.-GPT 9
The condyle moves away from a
horizontal reference plane at a 45-
degree angle.
The cusp tip of lower premolar
will move away from a
horizontal reference plane at a
45-degree angle. To avoid
eccentric contact between
premolars in a protrusive
movement, cuspal inclination
must be less than 45 degrees.
Steeper angle of the eminence
(condylar guidance) allows for
steeper posterior cusps

61. 61
TEMPOROMANDIBULAR
DISORDERS

62. 62
PROTECTIVE
CO-
CONTRACTION
LOCAL
MUSCLE
SORENESS
MYOFACIAL
PAIN
MYOSPASM
CENTRALLY
MEDIATED
MYALGIA
This is a central nervous system (CNS) response to injury or threat of injury, wherein it increases the
activity of the antagonist muscle during contraction of the agonist muscle.
Local muscle soreness is a primary noninflammatory myogenous pain disorder and is often
the first response of the muscle tissue to continued protective co-contraction.
Myospasm is an involuntary CNS-induced tonic muscle contraction.
It is a regional myogenous pain condition characterized by local areas of firm,
hypersensitive bands of muscle tissue known as trigger points. This condition is sometimes
referred to as myofascial trigger point pain
Centrally mediated myalgia is a chronic, regional, continuous muscle pain disorder
originating predominantly from CNS effects that are felt peripherally in the muscle tissues.

63. 63
TEMPOROMANDIBULAR JOINT DISORDERS
CONDYLE-DISC
COMPLEX
DERANGEMEN
T
DISC DISPLACEMENT
DISC DISLOCATION WITH
REDUCTION
DISC DISLOCATION WITH
INFERIOR RETRODISCAL
LIGAMENT
&
DISCAL COLLATERAL LIIGAMENT
Sincethe discand condyle no longer articulate, thiscondition isreferredto as
adiscdislocation .
Ifthepatient canso manipulate the jaw asto reposition thecondyle onto the posterior
border of thedisc,thediscissaid to bereduced.

64. 64
Structural
incompatibilities of
the articular
surface
DEVIATION IN
FORM
DISC
CONDYLE
FOSSA
ADHESION
DISC TO
CONDYLE
DISC TO FOSSA
SUBLUXATION
SPONTANEOUS
DISLOCATION

65. 65
INFLAMMATORY
DISORDERS
SYNOVITIS
ARTHRIDIDES
OSTEOARTHRITIS
OSTEOARTHROSIS
POLYARTHRIDIES
RETRODISCITIS
INFLAMMATORY
DISORDER OF
ASSOCIATED
STRUCTURES
TEMPORAL
TENDONITIS
STYLOMANDIBULAR
LIGAMENT
INFLAMMATION

66. 66
III. Chronic mandibular hypomobility
A.Ankylosis
1. Fibrous
2. Bony
B. Muscle contracture
1. Myostatic
2. Myofibrotic
C. Coronoid impedance
IV. Growth disorders
A. Congenital and developmental bone disorders
1. Agenesis
2. Hypoplasia
3. Hyperplasia
4. Neoplasia
B. Congenital and developmental muscle disorders
1. Hypotrophy
2. Hypertrophy
3. Neoplasia

67. OCCLUSAL SPLINT
67
Any removable device, usually made of hard polymethylmethacrylate,
which covers the occlusal and incisal surfaces of all the teeth in one
arch and maintains precise occlusal contact with the opposing teeth.
FUNCTION:-
a)Temporarily provide
orthopedically musculoskeletal
stable joint position
b)Introduces an optimum occlusal
condition that prevents muscular
hypertrophy.
c)Used to protect teeth from
occlusal wear.

68. TYPES OF SPLINT
68
PERMISSIVE
SPLINT
Allows the muscles to move the mandible
without interference from deflective tooth
inclines so the condyles can slide back and up
the articular eminence to complete seating
into centric relation.

69. DIRECTIVE SPLINT
69
Direct the lower arch into a specific
occlusal relationship that in turn
directs the condyles to a
predetermined position.

70. CONCLUSION
70
Dentists must assess the oral function of patients prior to any
treatment, since mastication is the most important oral
function and it is closely related to TMJ.
Proper knowledge of its anatomy & function are keys for
successful PROSTHODONTIC treatment

71. REFERENCES
71
1)JEFFREY P. OKESON Management of Temporomandibular disorders and occlusion.7th edition
2)PETER E. DAWSON Functional Occlusion from TMJ to Smile Design
3) J.R. ME´ RIDA-VELASCO,1* J.F. RODRI´GUEZ-VA´ ZQUEZ,1 J.A. ME´ RIDA-VELASCO,2 I. SA´
NCHEZ-MONTESINOS,2 J. ESPI´N-FERRA,2 AND J. JIME´ NEZ-COLLADO Development of the
Human Temporomandibular Joint. THE ANATOMICAL RECORD 255:20–33 (1999)
4)GRAY’S ANATOMY The anatomical basis of clinical practice. 41st edition
5) Claire E. Terhune Dietary correlates of temporomandibular joint morphology in New World
primates
Journal of Human Evolution 61 (2011) 583-596

72. 72