2. TABLE OF CONTENTS
• TYPES OF MOVEMENTS
Rotational
Axis of rotation:
• horizontal
• frontal
• sagittal
Translational
• BORDER MOVEMENTS
• FUNCTIONAL MOVEMENT
• ENVELOPE OF MOTION
• REVIEW OF LITERATURE
• SUMMARY
• CONCLUSION
3. MANDIBULAR MOVEMENTS:
• It is determined by combined and simultaneous
activities of both TMJs.
.
Mandibular movements are related to 3planes of the skull
Mandibular movements (GPT 8)- any movement in lower jaw.
5. Function:
Masseter contracts
Elevation of mandible
Superficial portion
Aid in protrusion of the
mandible
When the mandible is protruded &biting force is applied,
the fibres of the deep portion stabilize the condyle against
the articular eminence.
6.
7. ANTERIOR FIBRES
POSTERIOR FIBRES
(….fibres below the root
of the zygomatic process
are the
only significant ones)
Vertically raised….elevation
MIDDLE FIBRES…elevates& retrude
the mandible.
8. MEDIAL PTERYGOID:
Function :
Along with masseter it forms a
muscular sling that supports the
mandible at mandibular angle.
When fibers contract the mandible is
elevated.
Muscle is active in protruding the
mandible.
Unilateral contraction will bring about
mediotrusive movement of the
mandible.
9. LATERAL PTERYGOID:
Two bellies:
Inferior lateral pterygoid- outer surface of lateral pterygoid plate &extends
backward, upward& outward……inserted on to the neck of the condyle.
Superior lateral pterygoid- infratemporal surface of the greater wing of
sphenoid…..inserted on the articular capsule, the disc & the neck of the condyle.
11. Superior lateral pterygoid:
During opening… inferior pterygoid active
superior pterygoid remains inactive
Become active only in conjunction
with the elevator muscles
Closing ,Retracting ,Lateral movement ipsilateral in direction
14. Other muscles which are important for
mandibular function are:
Suprahyoid muscles
Infrahyoid muscles
Sternocleidomastoid
Posterior cervical muscles
Stabilizes the skull
& enables controlled
movement of the
mandible
15. STRUCTURE OF THE TEMPOROMANDIBULAR JOINT:
The TMJ is the most complex joints in the body and is the
area in which the mandible articulates with the cranium.
Hinging movement in Provides for gliding
one plane movement
GINGLYMOID JOINT ARTHRODIAL JOINT
GINGLYMOARTHRODIAL JOINT
COMPOUND JOINT
SYNOVIAL JOINT
16.
17. ARTICULAR DISC:
SAGITTAL PLANE
It is a firm, oval, fibrous plate
positioned between mandibular condyle and the
articular fossa and eminance.
Most part devoid of any blood
vessels or nerve fibres…..however
extreme periphery is slightly
Innervated.
It serves as a nonossified bone.
Thus making TMJ as the
compound joint.
SUPERIOR JOINT CAVITY
INFERIOR JOINT CAVITY
18. The bony elements of the temporomandibular articulation are the
mandibular condyles below and the squamous temporal bone above.
An articular disc composed of fibrous tissue is interposed between the temporal
bone and the mandible.
Gliding movement
Hinge movement
Upper compartment Lower compartment
19. Disk merges with the capsule at the periphery and is firmly attached to the
condyle at its medial and lateral pole .
Disk is not attached to temporal bone ,thus it moves with the condyle as the latter
translates in relation to the articular eminence
The central area of disk is thinner and is called intermediate zone with thicker
peripheral
20. MANDIBULAR CONDYLE:
ANTERIOR VIEW
POSTERIOR VIEW
Convex portion of the mandible
that articulates with the cranium,
around which movement occurs.
Mediolateral length=15-20mm
Anteroposterior length=8-10mm
Articulating surface—extends
both anteriorly and posteriorly
to the most superior aspect
of condyle.
Medial pole serves as a
point of rotation.
21. LIGAMENTS:
Ligaments of the joints are made up of collagenous connective tissue.
Muscles move and ligaments limit. They do not stretch.
Ligaments do not enter actively into joint function ,rather they act as
passive restraining devices to limit & restrict border movements.
3 functional ligaments that support TMJ are :
Collateral ligament
Capsular ligament
Temporomandibular ligament
2 accessory ligaments are:-
Sphenomandibularligament
Stylomandibular ligament
22. COLLATERAL OR DISCAL LIGAMENTS:
Disc is designed to rotate on the condyle like a bucket handle that attaches to
medial and lateral poles of the condyle by DISCAL LIGAMENTS.
There are 2 types: Medial discal ligament
Lateral discal ligament
True ligaments:> composed of collagenous CT fibres.
therefore they do not stretch.
23. CAPSULAR LIGAMENTS:
It is the synovial capsule that completely
surrounds and encompasses the TMJ.
Function :
LATERAL VIEW
Resist medial ,lateral, or inferior forces that tend to
separate or dislocate the articular surfaces .
Retains the synovial fluid .
Well innervated so gives proprioceptive feedback
regarding position and movement of the joint.
24. TEMPOROMANDIBULAR LIGAMENT:
Lateral aspect of the capsular ligament is reinforced by
strong, tight fibers that make up the lateral or
temporomandibular ligament.
LATERAL VIEW
Composed of
Outer oblique portion
Inner horizontal portion
This ligament of the joint does not come into function until jaw opens to 20mm or more.
Oblique portion Inner portion
Resists excessive dropping
of the condyle. Therefore
limiting the mouth opening.
Limits posterior movement
of the condyle&disc thus
protects the retrodiscal tissue
from trauma.
influence the normal
opening movement of the
mandible
Prevents lateral pterygoid
muscles from overextension
26. Occlusion
CONDYLAR GUIDANCE:
Defined as ―mandibular guidance generated by the condyle and the
articular disc traversing the contours of the glenoid fossa ‖GPT
It is the path of movement taken by the condyle in the glenoid
fossa, this is dictated by the shape of the glenoid fossa.
Defined as the influence of the contacting
surface of the mandibular and the maxillary
anterior teeth during mandibular movements
.‖GPT
This is influenced by the lingual surfaces of
the maxillary anteriors which guide the
mandible during the protrusive movement.
INCISAL GUIDANCE
27. NEUROMUSCULAR FACTORS
The muscles that move, hold, or stabilize the mandible ---------- because
they receive impulses from the central nervous system
NEUROMUSCULAR REGULATION OF MANDIBULAR MOTION:
Impulses….>conscious level….>voluntary
mandibular movements
Impulses..>subconscious level of
CNS.>involuntary mandibular movements
or modification of voluntary
movements….as a result of stimulation of
oral receptors ,muscle receptors
PROPRIOCEPTORS..>receptors present principally in the
mandibular muscles and ligaments ,which provide
information about the location of the mandible in space.
28. CLASSIFICATION OF MANDIBULAR MOVEMENTS:
According to sharry:
Based on axis of movement:
Rotation around the transverse or hinge axis
Rotation around the anteroposterior or sagittal axis
Rotation around the vertical axis
Based on the direction of movement:
Opening movements
Closing movements
Protrusive movements
Lateral movements
Based on the extent on movement:
Border movements
Intra border movements
29. Based on habitual movements:
Speech
Mastication
Deglutition
Respiration
CNS:
Innate..>breathing &swallowing
Learned ..>chewing &speech
Nonfunctional movements
Bruxism
30. ACCORDING TO OKESON:
Based on type of movement within the TMJ:
•Rotational movement
•Translational movement
Based on the plane of border movements:
•Border movement in horizontal plane
•Border movement in frontal plane(vertical)
•Border movement in sagittal plane
33. Horizontal axis of rotation:
.
TERMINAL HINGE AXIS:
•When the condyles are in their most
superior position in the articular fossae
and the mouth is purely rotated open,
the axis around which movement
occurs.
34. Frontal (vertical) axis of rotation:
Mandibular movement around the frontal axis occurs when one condyle moves
anteriorly out of terminal hinge position with the vertical axis of opposite condyle
remaining in the terminal hinge position.
35. Sagittal axis of rotation:
Mandibular movement around the sagittal axis occurs when one condyle moves
inferiorly while the other remains in the terminal hinge position.
36. TRANSLATIONAL MOVEMENT:
Defined as a movement in which every point
of the moving object has simultaneously the
same velocity &direction .
Ex: During protrusion
During most normal movements of the mandible ,both rotation
&translation occur simultaneously.
This results in complex movements that are extremely difficult to
visualize.
37. .
When the mandible moves through the outer range of motion,
reproducible and describable limits result, which are called BORDER
MOVEMENTS
Mandibular movements are limited by ligaments and articular surface of
TMJ’s as well as the morphology and alignment of the teeth
Sagittal border & functional movements
Horizontal border & functional movements
Frontal border & functional movements
SINGLE-PLANE BORDER MOVEMENTS
Based on extent of movement
Border movement
Intraborder movement
Border movement -Mandibular movement at the limits dictated by anatomic
structure as viewed in a given plane.
38. SAGITTAL PLANE BORDER & FUNCTIONAL MOVEMENTS:
Four distinct movement components:
Posterior opening border
Anterior opening border
Superior contact border
Functional
Posterior & anterior opening
border movements
Limited primarily by the
ligaments &the
morphology of the TMJs.
Superior contact border
movements
Determined by the occlusal
&incisal surfaces of the
teeth.
Functional movements Not considered border
movement., becoz not
determined by an outer range of motion. Determined
by the conditional responses of the neuromuscular
39. POSTERIOR OPENING BORDER MOVEMENTS:
In the sagittal plane occurs as two-stage hinging
movement.
First stage:
.
In CR the mandible can be rotated around
the horizontal axis
20-25mm
At this point TM ligaments tighten continued opening results in
anterior and inferior translation of the condyle.
40. Second stage:
Opening beyond 20-25mm
Condyles translate
Location of the axis of
Rotation shifts to the rami
Condyles moving anteriorly
& inferiorly & the anterior portion of mandible is moving posteriorly and inferiorly
Maximum opening is reached when the capsule
ligament prevent further movement of condyles
Maximum opening is in range of ---40-60mm
41. ANTERIOR OPENING BORDER MOVEMENTS:
If the condyle were stabilized in this anterior position, a hinge movement can
occur ,when mandible is closing from maximally opened to maximum
protruded position.
.
.
42. Not a pure hinge
movement…>because produces eccentricity in
the anterior border movement
Because the maximum protrusive position
is determined in part by stylomandibular
ligaments, when closure occurs,
tightening of ligaments produces a
posterior movement of the condyles
43. SUPERIOR CONTACT BORDER MOVEMENTS:
of the occluding surfaces of the teeth
.
Its precise delineation depends on 5 factors:
• Amount of variation between centric relation and maximum
intercuspation.
• The steepness of the cuspal inclines of the posterior teeth.
• Amount of vertical and horizontal overlap of anterior teeth.
• Lingual morphology of maxillary anterior teeth.
• General interarch relationships of the teeth.
44. In centric relation position:
Initial tooth contacts in terminal hinge closure
occurs b/n
If muscular force is applied
to the mandible, a
Supero-anterior movement or shift
will occur untill the intercuspation
position is reached.
This CR to maximum intercuspation have a lateral component.
This slide present..>90% population
45. From early 1950’s to more recently the distance between MI and
CR has changed from
1.25 mm by Posselt
1.0mm by Schuyler
0.8 to 0.5mm by Ramfjord
0.2mm Dawson and Ramfjord
The 0.2mm discrepancy between optimum condylar
position& MI…>Considered physiological.
46. In ICP the opposing anterior teeth usually contact.
when mandible is protruded from maximum intercuspation, contact between
incisal edge of mandible teeth and lingual inclines of maxillary teeth results in an
anterio-inferior movement of mandible.
Continue till edge to edge position .at this time a horizontal pathway is followed.
47. This horizontal movement continue till incisal edge of mandibular teeth pass
beyond the incisal edge of maxillary teeth. Mandible moves in a superior direction
untill the posterior teeth contact.
occlusal surface of posterior teeth then
dictate the remaining pathway to the
maximum protrusive movement .
48. FUNCTIONAL MOVEMENTS:
• Occur during functional activity of the
mandible.
• Usually occur within border movements
therefore considered free movements.
• require maximum intercuspation and therefore typically begin at & below the
intercuspal position.
Functional movements (GPT 8)-all normal, proper, or characteristic movements of
the mandible made during speech, mastication, yawning, swallowing, and other
associated movements
Rest position is located approximately 2 to 4 mm below the intercuspal position
49. Rugh JD,Drago CJ: Vertical dimension: a study of clinical rest position and jaw
muscle activity, J Prosthet Dent
concluded that the muscles of mastication are apparently at their lowest level of
activity when the mandible is positioned approx 8mm infr and 3mm anterior to
ICP
The increased level of electromyographic muscle activity in this position are
indicative of myotatic reflex .Because this is not a true resting position ,the
position in which the mandible is maintained is more appropriately termed the
postural position .
Postural position (GPT 8)- any mandibular relationship occurring during minimal
muscle contraction
50. POSTURAL EFFECTS ON FUNCTIONAL MOVEMENTS:
•When head is positioned erect, postural position of mandible-2-
4mm
• If the face is directed 45 degrees upward as during drinking.
• If face is directed 30 degrees downward as during eating-
ALERT FEEDING POSITION…..significant in considering the
functional relationships of teeth.
51. HORIZONTAL PLANE BORDER & FUNCTIONAL MOVEMENTS:
Traditionally GOTHIC ARCH TRACER used for recording mandibular
movement in horizontal plane.
components:
Left lateral border
Continued left lateral border with protrusion
Right lateral border
Continued right lateral border with protrusion
52. Left lateral border movements:
With the condyles in the centric relation position,,
the result will be a left lateral border movement.
Left condyle…>rotating condyle / working condyle
Right condyle…>orbiting condyle/nonworking condyle
left condyle still in the CR
53. Continued left lateral border movements with protrusion:
With the mandible in the left lateral border
position, contraction of the left inferior
lateral pterygoid along with continued
contraction of right inferior lateral
pterygoid will cause the left condyle to
move anteriorly to the right.
Cause a shift in the mandibular
midline back to coincide
with the midline of the face.
54. Right lateral border movements:
Mandible comes back
to the CR the right
lateral border movements
Left condyleorbiting
condyle…..as it orbiting
around the frontal axis
of the right condyle.
Right condylerotating
condyle…because the
mandible is rotating around it.
55. Continued right lateral border movements with protrusion:
With the mandible in the right lateral border position,
contraction of the right inferior lateral pterygoid along with
continued contraction of left inferior lateral pterygoid will cause
the right condyle to move anteriorly to the left.
56. Lateral movements can be generated by varying
levels of mandibular opening .
With each increasing degree of opening- smaller tracings will
result
57. Functional movements:
. Occur near the ICP
During chewing the range of jaw
movements begins some
distance from maximum
intercuspal position; but as the
food is broken down into smaller
particles, jaw action moves
closer and closer to intercuspal
position.
EC- area used in the early stages
of mastication
LC-area used in the later stages
of mastication
EEP-end- to end position of the
anterior position
58. FRONTAL (VERTICAL) BORDER &FUNCTIONAL MOVEMENTS:
A shield-shaped pattern can be seen
that has a functional component, &
four distinct movement components:-
Left lateral superior border.
Left lateral opening border.
Right lateral superior border
Right lateral opening border
59. Left lateral superior border movements:
With the mandible in the maximum intercuspation ,a lateral
movement is made to the left .
Inferiorly concave path.
Path determined by :
morphology &interarch relationships of the maxillary&
mandibular teeth that are in contact during this movement.
condyle –disc-fossa relationships & morphology of the
working or rotating side TMJ.
60. Left lateral opening border movements:
Laterally convex path.
As maximum opening is approached , ligaments tighten&
produce a medially directed movement that causes a shift
back in the mandibular midline to coincide with the midline
of the face.
61. Right lateral superior border movements:
From maximum intercuspation position a lateral movement is made to the right.
Slight differences may occur due to tooth contacts.
Right lateral opening border movements
62. Funtional movements:
Begin and end at the Intercuspal position.
During chewing mandible drops directly
inferiorly until desired opening is achieved.
It then shifts to the side on which the bolus
is placed and rises up.
in maximum intercuspation bolus is broken down
between opposing teeth.
In the final millimeter of closure, the mandible
shifts back to the intercuspal position.
63. ENVELOPE OF MOTION:
Represents maximum range of movement of the
mandible.
Given by POSSELT
For ex: during a simple lateral
movement ,motion occurs
around each axis& simultaneously
each axis tilts to accommodate to
the other axes.
All this happens within the envelope
of motion.
Controlled by the neuromuscular system to avoid injury
to any of the oral structures.
. This three dimensional space is called the envelope of
motion
64. ECCENTRIC MANDIBULAR MOVEMENT:
Protrusive
sagittal protrusive condylar path
sagittal protrusive incisal path
Mandibular movement anterior to centric relation .(GPT 8)
Occurs while incising and grasping food. This movement occurs after the condyle
rotates about in the TMJ.
Sagittal protrusive condylar path:
The orbit produced by the centres of the right & left condyles during
protrusive movement is referred to as the PROTRUSIVE CONDYLAR PATH.
S- shaped curve
65. Curve more obvious in dentulous patients than in edentulous.
Acc to AULL(1965), 8% form a straight line and 92% form a curve.
The angle formed by the protrusive condylar path and the horizontal reference plane
is called the
―SAGITTAL INCLINATION OF PROTRUSIVE CONDYLAR PATH.”
Acc to ISAACSON (1959) 35.60
Acc to LUNDEEN & WIRTH (1973) 45-500
Acc to HOBO (1982) 5-550 with a
mean of 30.40
66. Sagittal protrusive incisal path:
The orbit of the incisal point from maximum intercuspation to the edge-
to-edge occlusion is referred to as the PROTRUSIVE INCISAL PATH.
Mean length of this path is 5mm with variable paths in different
individuals.
Angle formed by the protrusive incisal path &the horizontal reference
plane is called the SAGITTAL INCLINATION OF PROTRUSIVE
INCISAL PATH.
Range between
50-70 degrees
Steeper than the
condylar path (HOBO, 1978)
67. LATERAL MOVEMENT
They are generally complex activities in most
humans.
Important as they influence the intercuspation
of the teeth during mastication.
Occurs when one condyle rotates within the
temporomandibular fossa and the other
condyle translates forward ,inward &
downward.
.
In practically all cases,however
lateral excursion is not a simple
Arc like movement
FISCHER (1952)
Lateral movement..>Sagittal plane
Horizontal plane
Movement from either right or left of the midsagittal plane (GPT 8).
68. Sagittal lateral condylar path:
When the orbit of the center of the nonworking condyle is traced on the sagittal
plane ….SAGITTAL LATERAL CONDYLAR PATH.
This path is longer and usually steeper
than the sagittal protrusive condylar path.
69. The angle formed between the sagittal protrusive condylar path and
sagittal lateral condylar path is called the FISCHER ANGLE ,with a mean
of 5 degrees.
The angle formed by the sagittal lateral condylar path and horizontal
reference plane is called the SAGITTAL INCLINATION OF LATERAL
CONDYLAR PATH.
The sagittal inclination of the lateral condylar path ranges between 11-61
degrees with a mean of 330
70. WORKING SIDE LATERAL MOVEMENT:
Dr.NORMAN GODFREY BENNETT(1908) initially studied
the working condylar path and called it BENNETT MOVEMENT,
now referred to as LATEROTRUSION.
Bennett showed that working condyle moves outwards
and nonworking condyle moves inwards.
McCollum considered it the most important determinant of occlusion.
Lateral movement in horizontal plane:
71. Bennett movement is usually recorded with a pantographic survey.
BENNETT SIDE SHIFT; is the bodily side shift of the mandible on the working
side in the horizontal plane.
It is also termed as mandibular lateral translation.
restraining influences of the
temporomandibular ligament on the
working condyle and to some extent by the
medial wall of glenoid fossa on the non
working side
The average lateral movement is about 0.75 mm (Lundeen et al; 1978)
72. NON WORKING SIDE LATERAL MOVEMENT:
The non working side will move forward , downward and medially.
this path of nonworking condyle is traced on horizontal plane it is known as the
HORIZONTAL LATERAL CONDYLAR PATH.
It has two components:
Immediate lateral translation
Progressive lateral translation
The Bennett side shift was classified based on
the timing of the shift in relation to the forward
movement of the non working condyle.
(lundeen ;1978)
73. Immediate lateral translation
Occurs when the nonworking condyle moves
from the centric relation straight inward or medially,
Mean movement ….>1mm (Lundeen,Wirth,1973)
In a study using electronic mandibular
device.
(Hobo,Mochizuki,1982)
Value of 0-2.6mm
with a mean of
0.42mm.
When downward forward and inward ,there is no ISS.
If medially downward and forward , there is ISS
74. Progressive lateral translation
Translatory portion of lateral movement that
occur at a rate proportional to forward movement of non working condyle
The progressive side shift determines the value of bennett angle
Bennett angle – angle formed between the
sagittal plane and the average path of the
advancing condyle as viewed in horizontal
plane during lateral mandibular movement
Angle is formed due to anterior and medial
movement of non working condyle .
Varies b/n 2-440 with a mean of 16.00
lateral movement occurs during the first 2-3mm of the forward movement of
the non working side .
75. Correlation between Bennett angle , immediate lateral
translation & progressive lateral translation:
Increase in the Bennett angle causes increase in the other two elements .
Immediate & progressive side shift can be calculated from the Bennett angle.
This method is effective when using the
interocclusal record method to determine
the horizontal lateral condylar path
76. Bennett movement regulated by
1. Anatomical configuration of glenoid fossa
2. Slackness of capsular ligaments
3. Contraction of medial pterygoid on non working
side
78. •Posselt (1956) J Prosthet Dent
With the aid of a
gnathothesiometer the area of
movement for 3 points on mandible
were recorded in the 3 main planes.
1 point was close to infradentale and
2 were in the middle of each
condyle.
79.
80. Joseph R. Jarabak (1956) J
Prosthet Dent
Electromyographically mandibular
movements in subjects wearing
dentures were studied.
81. It was found that correct vertical
dimension of occlusion coupled
with an adequate interocclusal
distance between the teeth of
upper and lower denture is
essential to maintain the
muscles of mastication at there
most efficient functional length.
82. •Hickey et al. ( 1957) J Prosthet
Dent.
In this study 3 identical
dentures and various food stuff
masticated while
electromyographic tracings were
made..
83. • It was concluded that ext.
pterygoid and suprahyoid muscles
were responsible for uncontrolled
opening movement while
masseter and temporal muscles
for closing movement
• Both external pterygoid muscles
were responsible for the
protrusion of mandible
84. • William W Wood ( 1987) J
Prosthet Dent
According to this article-
• Elevator muscles demonstrate
maximum activity when even
bilateral occlusal contacts occur
during clenching in the intercuspal
position.
85. • Ferrario et al. (1992) Int J
Prosthodont.
They found that males have
a significantly greater mean value
of vertical rest position than do
females. There is no gender
difference in mean value of
maximum opening.
86. CONCLUSION
• The masticatory system is extremely complex.
• Mandibular movements is regulated by an intricate
neurologic control system made up of Brain, Brainstem,
and the PNS. Each movement is co-ordinated to
maximize function while minimizing damage to any
structure
87. • Precise movement of the mandible by the musculature is
required to move the teeth effeciently across each other
during function
• The mechanics and physiology of this movement hence
are basic to the study of masticatory function.
