TMJ AND MANDIBULARTMJ AND MANDIBULAR
MOVEMENTSMOVEMENTS
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
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CONTENTSCONTENTS
 IntroductionIntroduction
 Development of TMJDevelopment of TMJ
 Anatomy of TMJAnatomy of TMJ
 Mandibular movementsMandibular movements
 Neuroanatomy and physiologyNeuroanatomy and physiology
 ClassificationClassification
 Border movementsBorder movements
 Functional movementsFunctional movements
 Para functional movementsPara functional movements
 Methods of studyingMethods of studying
 Review of literatureReview of literature
 ConclusionConclusion
 bibliographybibliography www.indiandentalacademy.comwww.indiandentalacademy.com
 INTRODUCTIONINTRODUCTION
Maintaining healthy TMJ is a dynamic process inMaintaining healthy TMJ is a dynamic process in
which teeth, bone, muscle, connective tissue and TMJ allwhich teeth, bone, muscle, connective tissue and TMJ all
function optimally in a state of health that can be maintainedfunction optimally in a state of health that can be maintained
throughout a lifetime.throughout a lifetime.
 TMJ is one of the most important yet most poorly understoodTMJ is one of the most important yet most poorly understood
joint in the body because of its unique anatomic position andjoint in the body because of its unique anatomic position and
association with other structuresassociation with other structures
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DefinitionsDefinitions
TMJTMJ: it is a diarthrodial, ginglymus, bicondylar variety of: it is a diarthrodial, ginglymus, bicondylar variety of
synovial joint where the condyloid process of the mandiblesynovial joint where the condyloid process of the mandible
and the aurticular disk articulates with the mandibular fossaand the aurticular disk articulates with the mandibular fossa
of temporal bone.of temporal bone.
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Synonyms of TMJSynonyms of TMJ ::
Jaw jointJaw joint
Diarthrodial jointDiarthrodial joint
Ginglymus jointGinglymus joint
Synovial jointSynovial joint
Complex jointComplex joint
Craniomandibular joint.Craniomandibular joint.
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Development of TMJDevelopment of TMJ
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12- prenatal week12- prenatal week
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1010thth
– 14– 14thth
weeksweeks
 SecondarySecondary
accessoryaccessory
cartilages appearcartilages appear
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14 week - condylar cartilage14 week - condylar cartilage
 Appears in the Ramal regionAppears in the Ramal region
 Endochondral boneEndochondral bone
(14 week)(14 week)
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ANATOMY OF TMJANATOMY OF TMJ
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Synovial fluidSynovial fluid
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BLOOD SUPPLYBLOOD SUPPLY
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Nerve supplyNerve supply
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Types of nerve endings in tmjTypes of nerve endings in tmj
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mandibular movementsmandibular movements
””any movement of the lower jaw”any movement of the lower jaw” by Glossary ofby Glossary of
prosthodontics – 8prosthodontics – 8
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1.1. Muscles of masticationMuscles of mastication
2.2. Supra and infra hyoid musclesSupra and infra hyoid muscles
Muscles of mandibularMuscles of mandibular
movementsmovements
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Muscles of masticationMuscles of mastication
 MasseterMasseter
 TemporalisTemporalis
 Lateral pterygoidLateral pterygoid
 Medial pterygoidMedial pterygoid
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Supra hyoid musclesSupra hyoid muscles
 DigastricDigastric
 Mylohyoid muscleMylohyoid muscle
 Geniohyoid musclesGeniohyoid muscles
 StylohyoidStylohyoid
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Neuroanatomy and physiology:Neuroanatomy and physiology:
Mandibular movements are based on impulses received fromMandibular movements are based on impulses received from
c.n.s:c.n.s:
1.senseromotor cortex – at concious level-voluntary movements.1.senseromotor cortex – at concious level-voluntary movements.
( opening, closing )( opening, closing )
2.reticular activating system – at subconcious level-involuntary2.reticular activating system – at subconcious level-involuntary
movements.movements.
they regulate muscle tone in mandibular rest positionthey regulate muscle tone in mandibular rest position
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types of receptors from which stimulus is perceivedtypes of receptors from which stimulus is perceived
exteroreceptors-exteroreceptors- ( pain, touch, heat, pressure )( pain, touch, heat, pressure )
from oral mucous membranefrom oral mucous membrane
proprioreceptorsproprioreceptors- from mandibular muscles, tmj- from mandibular muscles, tmj
periodontal ligamentperiodontal ligament
cranial nerves involved in mandibular movement are:cranial nerves involved in mandibular movement are:
trigeminal nervetrigeminal nerve
facial nervefacial nerve
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factors affecting mandibular movements:factors affecting mandibular movements:
1. posteriorly the two tmj1. posteriorly the two tmj
2. anteriorly by teeth of maxillary and mandibular arches2. anteriorly by teeth of maxillary and mandibular arches
3. muscles and ligaments attached to mandible3. muscles and ligaments attached to mandible
4. neuromuscular control of muscles of mandibular4. neuromuscular control of muscles of mandibular
movementmovement
5. size of mandible5. size of mandible
6. Axis of mandibular movements6. Axis of mandibular movements
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Mandibular movements can be broadly classified :Mandibular movements can be broadly classified :
Based on the dimension (or) Based on the movementBased on the dimension (or) Based on the movement
 RotationalRotational
 TranslationalTranslational
Based on the type of movementsBased on the type of movements
- hinge- hinge movementmovement
- protrusive movement- protrusive movement
- retrusive- retrusive movementmovement
- lateral- lateral movementmovement
1.lateral rotation or laterotrusion1.lateral rotation or laterotrusion
2.lateral translation or Bennett movement2.lateral translation or Bennett movement
-- immediate side shiftimmediate side shift
- precurrent side shift- precurrent side shift
- progressive side shift- progressive side shift
Based on the extend of movementBased on the extend of movement
border movementsborder movements
intra border movementsintra border movements
- functional movement- functional movement
- Parafunctional movement- Parafunctional movement
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 TranslationTranslation, when all, when all
points within a bodypoints within a body
have identical motion,have identical motion,
andand
 Rotation,Rotation, when thewhen the
body is turning aboutbody is turning about
an axesan axes
BASEDBASED ON THE DIMENSION BASED ON THE MOVEMENTON THE DIMENSION BASED ON THE MOVEMENT
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Rotation; translationRotation; translation
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Rotational MovementRotational Movement
DefDef :: Acc to DorlandsAcc to Dorlands:: the process of turning aroundthe process of turning around
an axis; movement of body about its axisan axis; movement of body about its axis
Rotation occurs in 3 planesRotation occurs in 3 planes
 HorizontalHorizontal
 Frontal [vertical]Frontal [vertical]
 SaggitalSaggital
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HORIZONTAL PLANEHORIZONTAL PLANE
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SAGITTAL PLANE.SAGITTAL PLANE.
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FRONTAL PLANEFRONTAL PLANE
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TranslationTranslation
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BASED ON THE EXTEND OFBASED ON THE EXTEND OF
MOVEMENTMOVEMENT
BordermovementsBordermovements
““mandibular movements at the limits dictated bymandibular movements at the limits dictated by
anatomic structures, as viewed in a given plane”-anatomic structures, as viewed in a given plane”-
GPTGPT
• Extreme movements in the sagittalExtreme movements in the sagittal planeplane
• Extreme movements in the horizontal planeExtreme movements in the horizontal plane
• Extreme movements in the coronal planeExtreme movements in the coronal plane
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EXTREME MOVEMENTS IN THEEXTREME MOVEMENTS IN THE
SAGITTAL PLANE :SAGITTAL PLANE :
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Posterior opening borderPosterior opening border
movementsmovements
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Anterior opening borderAnterior opening border
movementsmovements::
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Superior contact bordermovementsSuperior contact bordermovements
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FUNCTIONAL MOVEMENTSFUNCTIONAL MOVEMENTS
1.Posterior opening border,
2.Anterior opening border,
3.Superior contact border,
4.Functional movement
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DRINKING POSITIONDRINKING POSITION::
POSTURAL EFFECTS OFPOSTURAL EFFECTS OF
FUNCTIONALFUNCTIONAL MOVEMENTSMOVEMENTS::
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ALERT FEEDING POSITIONALERT FEEDING POSITION
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EXTREME MOVEMENTS IN THE HORIZONTALEXTREME MOVEMENTS IN THE HORIZONTAL
PLANE :PLANE :
 Traditionally a device calledTraditionally a device called ""GOTHIC ARCHGOTHIC ARCH"" is used tois used to
record thisrecord this
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 It has 4 distinct movements:It has 4 distinct movements:
Left lateral borderLeft lateral border
Continued left lateral borderContinued left lateral border
Right lateral borderRight lateral border
Continued Right lateral border with protrusionContinued Right lateral border with protrusion
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LEFT LATERAL BORDERLEFT LATERAL BORDER::
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CONTINUED LEFT LATERAL BORDERCONTINUED LEFT LATERAL BORDER
MOVMENTMOVMENT::
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RIGHT LATERAL BORDERRIGHT LATERAL BORDER
MOVEMENTSMOVEMENTS::
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CONTINUED RIGHT LATERAL BORDERCONTINUED RIGHT LATERAL BORDER
MOVEMENTMOVEMENT::
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Mandibular border movements in
horizontal plane recorded at various
degrees of mouth opening.
1.Left lateral, 2.continuous left lateral,
3.right lateral, 4.continuous right
lateral, CR – centric relation, ICP –
inter cuspal position
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EXTREME MOVEMENTS IN THE FRONTALEXTREME MOVEMENTS IN THE FRONTAL
PLANE :PLANE :
 Border movements in thisBorder movements in this
plane produce aplane produce a
charecteristic “shieldcharecteristic “shield
tracing”tracing”
 This has four movementThis has four movement
components.components.
 Left lateral superior borderLeft lateral superior border
 Left lateral opening borderLeft lateral opening border
 Right lateral superior borderRight lateral superior border
 Right lateral opening borderRight lateral opening borderwww.indiandentalacademy.comwww.indiandentalacademy.com
Left lateral superior borderLeft lateral superior border
movementsmovements
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LEFT LATERAL OPENING BORDERLEFT LATERAL OPENING BORDER
MOVEMENTMOVEMENT
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RIGHT LATERAL SUPERIOR BORDERRIGHT LATERAL SUPERIOR BORDER
MOVEMENTSMOVEMENTS
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RIGHT LATERAL OPENING BORDERRIGHT LATERAL OPENING BORDER
MOVEMENTS:MOVEMENTS:
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ENVELOPE OF MOTIONENVELOPE OF MOTION::
 When we combine the borderWhen we combine the border
movements of all the three planes,movements of all the three planes,
we get a three-dimensional spacewe get a three-dimensional space
within which mandibular movementwithin which mandibular movement
is possible.is possible.
 This three dimensional limitingThis three dimensional limiting
space is called as “Envelope ofspace is called as “Envelope of
motion” which was first describedmotion” which was first described
byby PosseltPosselt in 1952.in 1952.
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PROTRUSIVE MOVEMENTPROTRUSIVE MOVEMENT
 Occurs while incising and grasping food. This movementOccurs while incising and grasping food. This movement
occurs after the condyle rotates about 13º in the TMJ. At thisoccurs after the condyle rotates about 13º in the TMJ. At this
point the transverse hinge axis shifts to the level of thepoint the transverse hinge axis shifts to the level of the
mandibular foramen.mandibular foramen.
 The mandible moves forward and downwards. This movementThe mandible moves forward and downwards. This movement
is complete when the maxillary and the Mandibular teeth areis complete when the maxillary and the Mandibular teeth are
edge to edge.edge to edge.
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RETRUSIVE MOVEMENTRETRUSIVE MOVEMENT
 Occurs when the mandible is forcefully moved behind theOccurs when the mandible is forcefully moved behind the
centric relation. The patient cannot voluntarilycentric relation. The patient cannot voluntarily reproduce it.reproduce it.
 Brought about by the fibers of the temporalis, digastric and theBrought about by the fibers of the temporalis, digastric and the
deep fibers of the masseter. The magnitude is 0.5mm.deep fibers of the masseter. The magnitude is 0.5mm.
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LATERAL MOVEMENTLATERAL MOVEMENT
 Lateral rotation or laterotrusionLateral rotation or laterotrusion
 Bennett movementBennett movement
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Lateral rotationLateral rotation
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In the working side any of the following fiveIn the working side any of the following five
movements can take place .movements can take place .
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BENNETTBENNETT MOVEMENTMOVEMENT
 It is defined as the bodily lateralIt is defined as the bodily lateral
movement or lateral shift of themovement or lateral shift of the
mandible resulting from themandible resulting from the
movement of the condyle alongmovement of the condyle along
the lateral inclines along thethe lateral inclines along the
mandibular fossae in lateral jawmandibular fossae in lateral jaw
movements.movements.
 This movement is recorded in theThis movement is recorded in the
non workingnon working side .The shift is 1-side .The shift is 1-
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 The Bennett shift is classified based on the timing of the shiftThe Bennett shift is classified based on the timing of the shift
in relation to the forward movement of the non workingin relation to the forward movement of the non working
condyle.condyle.
 Immediate side shift.Immediate side shift.
 Precurrent side shiftPrecurrent side shift
 Progressive side shiftProgressive side shift
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IMMEDIATE SIDE SHIFTIMMEDIATE SIDE SHIFT
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PRECURRENT SIDE SHIFTPRECURRENT SIDE SHIFT
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PROGRESSIVE SIDE SHIFTPROGRESSIVE SIDE SHIFT
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 Bennett MovementBennett Movement has 3 attributes:has 3 attributes:
 AmountAmount
 TimingTiming
 DirectionDirection
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Bennett angleBennett angle
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BALKWILL’S MOVEMENTBALKWILL’S MOVEMENT
 Although Bennett has described about this movementAlthough Bennett has described about this movement
which became popularly known as Bennett movement, thewhich became popularly known as Bennett movement, the
original discovery of this movement should go tooriginal discovery of this movement should go to
BALKWILLBALKWILL..
 As early as 1870As early as 1870 BALKWILLBALKWILL observed that theobserved that the
mandible opened and closed on an axis that runs through themandible opened and closed on an axis that runs through the
condyles, that the condyles move downwards and forwards incondyles, that the condyles move downwards and forwards in
protrusion and also the mandible moves bodily from side toprotrusion and also the mandible moves bodily from side to
side.side.
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STRUCTURES CONTROLLINGSTRUCTURES CONTROLLING
MANDIBULAR MOVEMENT:MANDIBULAR MOVEMENT:
 The structures controlling Mandibular movement are dividedThe structures controlling Mandibular movement are divided
into two types;into two types;
 Posterior controlling factorsPosterior controlling factors
 Anterior controlling factorsAnterior controlling factors
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Intra border movements :Intra border movements :
These movements occur within theThese movements occur within the envelope of motion.envelope of motion. They areThey are
of two types namelyof two types namely
 Functional movementFunctional movement
 ParafunctionalParafunctional movementsmovements
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FUNCTIONAL MANDIBULAR MOVEMENTSFUNCTIONAL MANDIBULAR MOVEMENTS
They are natural and characteristic movements that occursThey are natural and characteristic movements that occurs
during mastication, speech and yawning.during mastication, speech and yawning.
 Mandibular openingMandibular opening
 Mandibular closingMandibular closing
 retractionretraction
 Lateral movementLateral movement
 MasticationMastication
 SwallowingSwallowing
 SpeakingSpeaking
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PARAFUNCTIONALPARAFUNCTIONAL
MANDIBULAR MOVEMENTSMANDIBULAR MOVEMENTS
They Are UncharacteristicThey Are Uncharacteristic and Unnatural Movements Likeand Unnatural Movements Like
 Bruxism,Bruxism,
 ClenchingClenching
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Bruxism:Bruxism:
The neuromuscular reaction to occlusal interference byThe neuromuscular reaction to occlusal interference by
seeking them out and grinding on them. When grinding is ofseeking them out and grinding on them. When grinding is of
transient nature, it is called parafunctional grinding whereastransient nature, it is called parafunctional grinding whereas
chronic destructive habit may be referred as bruxism.chronic destructive habit may be referred as bruxism.
Clenching:Clenching:
It is defined as forceful clamping together of jaws in staticIt is defined as forceful clamping together of jaws in static
relationship. Considerable amount of force is maintained forrelationship. Considerable amount of force is maintained for
several seconds or even longer.several seconds or even longer.
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METHODS OF STUDYINGMETHODS OF STUDYING
MANDIBULAR MOVEMENTMANDIBULAR MOVEMENT
 Mandibular, particularly condyle, activities has been studiedMandibular, particularly condyle, activities has been studied
for many years by a variety of methods ranging from directfor many years by a variety of methods ranging from direct
clinical observations to sophisticated electronic instruments.clinical observations to sophisticated electronic instruments.
 1896. Warber used facial clinometer to measure mandibular1896. Warber used facial clinometer to measure mandibular
movements.movements.
 1908. Bennet traced the pathway of light positioned the1908. Bennet traced the pathway of light positioned the
condyle.condyle.
 1931. Hildebrand recorded condyle movements by Roentgen1931. Hildebrand recorded condyle movements by Roentgen
fluoroscopy.fluoroscopy.
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 Recently used areRecently used are
 direct examination: based on examination of facets anddirect examination: based on examination of facets and
wear patternswear patterns
 cinematographic techniques: by using motion picturescinematographic techniques: by using motion pictures
 cine –radiological studies: use serial tracings of successivecine –radiological studies: use serial tracings of successive
frames of filmframes of film
 pantography: it is one of the best methods of studyingpantography: it is one of the best methods of studying
mandibular movementsmandibular movements
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mechanical pantography:mechanical pantography:
these are devices containing two facebows one fixed to maxillathese are devices containing two facebows one fixed to maxilla
and other fixed to mandible. One holds writing device andand other fixed to mandible. One holds writing device and
other holds recording tableother holds recording table
in pantography proceduremovements are recorded inin pantography proceduremovements are recorded in
three planes- horizontal, frontal, sagittalthree planes- horizontal, frontal, sagittal
these were developed by mac collum and stuart (1955)these were developed by mac collum and stuart (1955)
disadvantages-disadvantages-
require complex handling procedures in clinics and laboratoryrequire complex handling procedures in clinics and laboratory
size and weight are cumbersomesize and weight are cumbersome
electronic pantographyelectronic pantography : by hobo and takayama: by hobo and takayama
measures right and left eccentric movements by means of smallmeasures right and left eccentric movements by means of small
opto- electronic sensor fixed to the maxilla.opto- electronic sensor fixed to the maxilla.
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55.ultrasonic instruments.ultrasonic instruments
6.6. electronic instrumentselectronic instruments
77. photoelastic technique. photoelastic technique
8.8. light emitting diodelight emitting diode
99. computer- monitered radionuclide tracings.. computer- monitered radionuclide tracings.
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REVIEW OF LITERATURE:REVIEW OF LITERATURE:
Michael gardener did a study on voluntary mandibularMichael gardener did a study on voluntary mandibular
lateral translation concerning its existence, magnitude, andlateral translation concerning its existence, magnitude, and
timing and concluded all subjects showed evidence oftiming and concluded all subjects showed evidence of
mandibular lateral translation. New definitions for timing ofmandibular lateral translation. New definitions for timing of
mandibular lateral transition are proposed. Of the tracings, 64%mandibular lateral transition are proposed. Of the tracings, 64%
exhibited as early translation, 30 % as intermediate, 4 % as lateexhibited as early translation, 30 % as intermediate, 4 % as late
mandibular translation.mandibular translation.
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Jack D preston did a study on reassessment of mandibularJack D preston did a study on reassessment of mandibular
transverse horizontal axis theory and concluded that a singletransverse horizontal axis theory and concluded that a single
transverse horizontal axis can usually appear to be located.transverse horizontal axis can usually appear to be located.
Location of kinematic axis is a worth while clinical procedureLocation of kinematic axis is a worth while clinical procedure
to transfer an arc of rotation in the saggital plane from theto transfer an arc of rotation in the saggital plane from the
patient to an articulator. The anatomic asymmetries of the axispatient to an articulator. The anatomic asymmetries of the axis
transfer procedure may result in cast dislocations that maytransfer procedure may result in cast dislocations that may
produce undesirable alterations in esthetic tooth positions.produce undesirable alterations in esthetic tooth positions.
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Marta , Luciana did a model to simulate the masticationMarta , Luciana did a model to simulate the mastication
motion at the temperomandibular joint and concluded thatmotion at the temperomandibular joint and concluded that
although most mandibular functions involve only a smallalthough most mandibular functions involve only a small
range of mouth opening, the maximal position that jaw canrange of mouth opening, the maximal position that jaw can
reach at frontal, saggital, lateral planes produce a widereach at frontal, saggital, lateral planes produce a wide
range of movements ( upto 6 degrees of freedomrange of movements ( upto 6 degrees of freedom
considering the sliding of jaw condyles)considering the sliding of jaw condyles)
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Warren c rivera,barry m goldman, and Richard s made aWarren c rivera,barry m goldman, and Richard s made a
simplified technique to measure mandibular range of motionsimplified technique to measure mandibular range of motion
in which tongue blade is used to mark and measure maximumin which tongue blade is used to mark and measure maximum
opening and eccentric movements which is more accurate thanopening and eccentric movements which is more accurate than
other techniques proposed for the same purpose. Because of itsother techniques proposed for the same purpose. Because of its
low cost, convenience, and ease of use the tongue bladelow cost, convenience, and ease of use the tongue blade
technique is more practical way to document range of motiontechnique is more practical way to document range of motion
than mandibular kinesiograph.than mandibular kinesiograph.
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Jill k Rendell, Thomas gay did a study on denture adhesiveJill k Rendell, Thomas gay did a study on denture adhesive
on mandibular movement during chewing and concludedon mandibular movement during chewing and concluded
that use of denture adhesive increased the mean chewingthat use of denture adhesive increased the mean chewing
rate in test subjects immediately after and at two and fourrate in test subjects immediately after and at two and four
hours after denture adhesive was applied these findingshours after denture adhesive was applied these findings
show that using a denture adhesive promotes a faster andshow that using a denture adhesive promotes a faster and
more natural rate of chewingmore natural rate of chewing
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conclusionconclusion
““ the articulation of human teeth is not athe articulation of human teeth is not a
simple thing, no single factoris dominant. all of thesimple thing, no single factoris dominant. all of the
interrelated factors are covered and are expressed ininterrelated factors are covered and are expressed in
articulating surfaces of teeth. These practices and proceduresarticulating surfaces of teeth. These practices and procedures
which neglect anyone factor are doomed to failure”.which neglect anyone factor are doomed to failure”.
( mac collum and staurt )( mac collum and staurt )
www.indiandentalacademy.comwww.indiandentalacademy.com
REFERENCESREFERENCES
1.Boucher's prosthodontic treatment for edentulous patients.1.Boucher's prosthodontic treatment for edentulous patients.
George A.Zarb et alGeorge A.Zarb et al
2.Contemporary fixed prosthodontics – Rosential,Land, Fujimoto2.Contemporary fixed prosthodontics – Rosential,Land, Fujimoto
3.Fundamentals of occlusion and temporomandibular disorders.3.Fundamentals of occlusion and temporomandibular disorders.
Jeffery P.OkesonJeffery P.Okeson
4.human anatomy –b.d.chaurasia’s4.human anatomy –b.d.chaurasia’s
5.Occlusion: sigurd Ramfjord, Major M.Ash.5.Occlusion: sigurd Ramfjord, Major M.Ash.
6.oral development and histology –james k avery.6.oral development and histology –james k avery.
7. Oral histology and embryology-james k avery.7. Oral histology and embryology-james k avery.
8.Osseointegration and rehabilitation. Sumiya Hobo et al.8.Osseointegration and rehabilitation. Sumiya Hobo et al.
9.Syllabus of complete denture. Charles M.Heartwell, Arthur9.Syllabus of complete denture. Charles M.Heartwell, Arthur
O.Rahn.O.Rahn.
www.indiandentalacademy.comwww.indiandentalacademy.com
10.an invitro study of voluntary mandibular lateral translation10.an invitro study of voluntary mandibular lateral translation
concerning its existence, magnitude, and timing J of prosthetconcerning its existence, magnitude, and timing J of prosthet
dent 1998; 80 ;672-679dent 1998; 80 ;672-679
11.a reassessment of the mandibular transverse horizontal axis11.a reassessment of the mandibular transverse horizontal axis
theory J of prosthet dent 2004;91;505-512theory J of prosthet dent 2004;91;505-512
12.a model to simulate the mastication motion at the12.a model to simulate the mastication motion at the
temperomandibular joint.temperomandibular joint.
13.a simplified technique to measure mandibular range of motion13.a simplified technique to measure mandibular range of motion
J of prosthet dent 1996;75; 56-59J of prosthet dent 1996;75; 56-59
14.the effect of denture adhesive on mandibular movement14.the effect of denture adhesive on mandibular movement
during chewing JADA 2000; 131;981-986during chewing JADA 2000; 131;981-986
www.indiandentalacademy.comwww.indiandentalacademy.com
THANK YOUTHANK YOU
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Mandibular movements

  • 1.
    TMJ AND MANDIBULARTMJAND MANDIBULAR MOVEMENTSMOVEMENTS INDIAN DENTAL ACADEMY Leader in continuing Dental Education www.indiandentalacademy.comwww.indiandentalacademy.com
  • 2.
    CONTENTSCONTENTS  IntroductionIntroduction  Developmentof TMJDevelopment of TMJ  Anatomy of TMJAnatomy of TMJ  Mandibular movementsMandibular movements  Neuroanatomy and physiologyNeuroanatomy and physiology  ClassificationClassification  Border movementsBorder movements  Functional movementsFunctional movements  Para functional movementsPara functional movements  Methods of studyingMethods of studying  Review of literatureReview of literature  ConclusionConclusion  bibliographybibliography www.indiandentalacademy.comwww.indiandentalacademy.com
  • 3.
     INTRODUCTIONINTRODUCTION Maintaining healthyTMJ is a dynamic process inMaintaining healthy TMJ is a dynamic process in which teeth, bone, muscle, connective tissue and TMJ allwhich teeth, bone, muscle, connective tissue and TMJ all function optimally in a state of health that can be maintainedfunction optimally in a state of health that can be maintained throughout a lifetime.throughout a lifetime.  TMJ is one of the most important yet most poorly understoodTMJ is one of the most important yet most poorly understood joint in the body because of its unique anatomic position andjoint in the body because of its unique anatomic position and association with other structuresassociation with other structures www.indiandentalacademy.comwww.indiandentalacademy.com
  • 4.
    DefinitionsDefinitions TMJTMJ: it isa diarthrodial, ginglymus, bicondylar variety of: it is a diarthrodial, ginglymus, bicondylar variety of synovial joint where the condyloid process of the mandiblesynovial joint where the condyloid process of the mandible and the aurticular disk articulates with the mandibular fossaand the aurticular disk articulates with the mandibular fossa of temporal bone.of temporal bone. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 5.
    Synonyms of TMJSynonymsof TMJ :: Jaw jointJaw joint Diarthrodial jointDiarthrodial joint Ginglymus jointGinglymus joint Synovial jointSynovial joint Complex jointComplex joint Craniomandibular joint.Craniomandibular joint. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 6.
    Development of TMJDevelopmentof TMJ www.indiandentalacademy.comwww.indiandentalacademy.com
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    12- prenatal week12-prenatal week www.indiandentalacademy.comwww.indiandentalacademy.com
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    1010thth – 14– 14thth weeksweeks SecondarySecondary accessoryaccessory cartilages appearcartilages appear www.indiandentalacademy.comwww.indiandentalacademy.com
  • 10.
    14 week -condylar cartilage14 week - condylar cartilage  Appears in the Ramal regionAppears in the Ramal region  Endochondral boneEndochondral bone (14 week)(14 week) www.indiandentalacademy.comwww.indiandentalacademy.com
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    ANATOMY OF TMJANATOMYOF TMJ www.indiandentalacademy.comwww.indiandentalacademy.com
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    Types of nerveendings in tmjTypes of nerve endings in tmj www.indiandentalacademy.comwww.indiandentalacademy.com
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    mandibular movementsmandibular movements ””anymovement of the lower jaw”any movement of the lower jaw” by Glossary ofby Glossary of prosthodontics – 8prosthodontics – 8 www.indiandentalacademy.comwww.indiandentalacademy.com
  • 17.
    1.1. Muscles ofmasticationMuscles of mastication 2.2. Supra and infra hyoid musclesSupra and infra hyoid muscles Muscles of mandibularMuscles of mandibular movementsmovements www.indiandentalacademy.comwww.indiandentalacademy.com
  • 18.
    Muscles of masticationMusclesof mastication  MasseterMasseter  TemporalisTemporalis  Lateral pterygoidLateral pterygoid  Medial pterygoidMedial pterygoid www.indiandentalacademy.comwww.indiandentalacademy.com
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    Supra hyoid musclesSuprahyoid muscles  DigastricDigastric  Mylohyoid muscleMylohyoid muscle  Geniohyoid musclesGeniohyoid muscles  StylohyoidStylohyoid www.indiandentalacademy.comwww.indiandentalacademy.com
  • 24.
    Neuroanatomy and physiology:Neuroanatomyand physiology: Mandibular movements are based on impulses received fromMandibular movements are based on impulses received from c.n.s:c.n.s: 1.senseromotor cortex – at concious level-voluntary movements.1.senseromotor cortex – at concious level-voluntary movements. ( opening, closing )( opening, closing ) 2.reticular activating system – at subconcious level-involuntary2.reticular activating system – at subconcious level-involuntary movements.movements. they regulate muscle tone in mandibular rest positionthey regulate muscle tone in mandibular rest position www.indiandentalacademy.comwww.indiandentalacademy.com
  • 25.
    types of receptorsfrom which stimulus is perceivedtypes of receptors from which stimulus is perceived exteroreceptors-exteroreceptors- ( pain, touch, heat, pressure )( pain, touch, heat, pressure ) from oral mucous membranefrom oral mucous membrane proprioreceptorsproprioreceptors- from mandibular muscles, tmj- from mandibular muscles, tmj periodontal ligamentperiodontal ligament cranial nerves involved in mandibular movement are:cranial nerves involved in mandibular movement are: trigeminal nervetrigeminal nerve facial nervefacial nerve www.indiandentalacademy.comwww.indiandentalacademy.com
  • 26.
    factors affecting mandibularmovements:factors affecting mandibular movements: 1. posteriorly the two tmj1. posteriorly the two tmj 2. anteriorly by teeth of maxillary and mandibular arches2. anteriorly by teeth of maxillary and mandibular arches 3. muscles and ligaments attached to mandible3. muscles and ligaments attached to mandible 4. neuromuscular control of muscles of mandibular4. neuromuscular control of muscles of mandibular movementmovement 5. size of mandible5. size of mandible 6. Axis of mandibular movements6. Axis of mandibular movements www.indiandentalacademy.comwww.indiandentalacademy.com
  • 27.
    Mandibular movements canbe broadly classified :Mandibular movements can be broadly classified : Based on the dimension (or) Based on the movementBased on the dimension (or) Based on the movement  RotationalRotational  TranslationalTranslational Based on the type of movementsBased on the type of movements - hinge- hinge movementmovement - protrusive movement- protrusive movement - retrusive- retrusive movementmovement - lateral- lateral movementmovement 1.lateral rotation or laterotrusion1.lateral rotation or laterotrusion 2.lateral translation or Bennett movement2.lateral translation or Bennett movement -- immediate side shiftimmediate side shift - precurrent side shift- precurrent side shift - progressive side shift- progressive side shift Based on the extend of movementBased on the extend of movement border movementsborder movements intra border movementsintra border movements - functional movement- functional movement - Parafunctional movement- Parafunctional movement www.indiandentalacademy.comwww.indiandentalacademy.com
  • 28.
     TranslationTranslation, whenall, when all points within a bodypoints within a body have identical motion,have identical motion, andand  Rotation,Rotation, when thewhen the body is turning aboutbody is turning about an axesan axes BASEDBASED ON THE DIMENSION BASED ON THE MOVEMENTON THE DIMENSION BASED ON THE MOVEMENT www.indiandentalacademy.comwww.indiandentalacademy.com
  • 29.
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    Rotational MovementRotational Movement DefDef:: Acc to DorlandsAcc to Dorlands:: the process of turning aroundthe process of turning around an axis; movement of body about its axisan axis; movement of body about its axis Rotation occurs in 3 planesRotation occurs in 3 planes  HorizontalHorizontal  Frontal [vertical]Frontal [vertical]  SaggitalSaggital www.indiandentalacademy.comwww.indiandentalacademy.com
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    BASED ON THEEXTEND OFBASED ON THE EXTEND OF MOVEMENTMOVEMENT BordermovementsBordermovements ““mandibular movements at the limits dictated bymandibular movements at the limits dictated by anatomic structures, as viewed in a given plane”-anatomic structures, as viewed in a given plane”- GPTGPT • Extreme movements in the sagittalExtreme movements in the sagittal planeplane • Extreme movements in the horizontal planeExtreme movements in the horizontal plane • Extreme movements in the coronal planeExtreme movements in the coronal plane • Envelope of motionEnvelope of motionwww.indiandentalacademy.comwww.indiandentalacademy.com
  • 36.
    EXTREME MOVEMENTS INTHEEXTREME MOVEMENTS IN THE SAGITTAL PLANE :SAGITTAL PLANE : www.indiandentalacademy.comwww.indiandentalacademy.com
  • 37.
    Posterior opening borderPosterioropening border movementsmovements www.indiandentalacademy.comwww.indiandentalacademy.com
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    Anterior opening borderAnterioropening border movementsmovements:: www.indiandentalacademy.comwww.indiandentalacademy.com
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    Superior contact bordermovementsSuperiorcontact bordermovements www.indiandentalacademy.comwww.indiandentalacademy.com
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    FUNCTIONAL MOVEMENTSFUNCTIONAL MOVEMENTS 1.Posterioropening border, 2.Anterior opening border, 3.Superior contact border, 4.Functional movement www.indiandentalacademy.comwww.indiandentalacademy.com
  • 46.
    DRINKING POSITIONDRINKING POSITION:: POSTURALEFFECTS OFPOSTURAL EFFECTS OF FUNCTIONALFUNCTIONAL MOVEMENTSMOVEMENTS:: www.indiandentalacademy.comwww.indiandentalacademy.com
  • 47.
    ALERT FEEDING POSITIONALERTFEEDING POSITION www.indiandentalacademy.comwww.indiandentalacademy.com
  • 48.
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    EXTREME MOVEMENTS INTHE HORIZONTALEXTREME MOVEMENTS IN THE HORIZONTAL PLANE :PLANE :  Traditionally a device calledTraditionally a device called ""GOTHIC ARCHGOTHIC ARCH"" is used tois used to record thisrecord this www.indiandentalacademy.comwww.indiandentalacademy.com
  • 51.
     It has4 distinct movements:It has 4 distinct movements: Left lateral borderLeft lateral border Continued left lateral borderContinued left lateral border Right lateral borderRight lateral border Continued Right lateral border with protrusionContinued Right lateral border with protrusion www.indiandentalacademy.comwww.indiandentalacademy.com
  • 52.
    LEFT LATERAL BORDERLEFTLATERAL BORDER:: www.indiandentalacademy.comwww.indiandentalacademy.com
  • 53.
    CONTINUED LEFT LATERALBORDERCONTINUED LEFT LATERAL BORDER MOVMENTMOVMENT:: www.indiandentalacademy.comwww.indiandentalacademy.com
  • 54.
    RIGHT LATERAL BORDERRIGHTLATERAL BORDER MOVEMENTSMOVEMENTS:: www.indiandentalacademy.comwww.indiandentalacademy.com
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    CONTINUED RIGHT LATERALBORDERCONTINUED RIGHT LATERAL BORDER MOVEMENTMOVEMENT:: www.indiandentalacademy.comwww.indiandentalacademy.com
  • 56.
    Mandibular border movementsin horizontal plane recorded at various degrees of mouth opening. 1.Left lateral, 2.continuous left lateral, 3.right lateral, 4.continuous right lateral, CR – centric relation, ICP – inter cuspal position www.indiandentalacademy.comwww.indiandentalacademy.com
  • 57.
    EXTREME MOVEMENTS INTHE FRONTALEXTREME MOVEMENTS IN THE FRONTAL PLANE :PLANE :  Border movements in thisBorder movements in this plane produce aplane produce a charecteristic “shieldcharecteristic “shield tracing”tracing”  This has four movementThis has four movement components.components.  Left lateral superior borderLeft lateral superior border  Left lateral opening borderLeft lateral opening border  Right lateral superior borderRight lateral superior border  Right lateral opening borderRight lateral opening borderwww.indiandentalacademy.comwww.indiandentalacademy.com
  • 58.
    Left lateral superiorborderLeft lateral superior border movementsmovements www.indiandentalacademy.comwww.indiandentalacademy.com
  • 59.
    LEFT LATERAL OPENINGBORDERLEFT LATERAL OPENING BORDER MOVEMENTMOVEMENT www.indiandentalacademy.comwww.indiandentalacademy.com
  • 60.
    RIGHT LATERAL SUPERIORBORDERRIGHT LATERAL SUPERIOR BORDER MOVEMENTSMOVEMENTS www.indiandentalacademy.comwww.indiandentalacademy.com
  • 61.
    RIGHT LATERAL OPENINGBORDERRIGHT LATERAL OPENING BORDER MOVEMENTS:MOVEMENTS: www.indiandentalacademy.comwww.indiandentalacademy.com
  • 62.
    ENVELOPE OF MOTIONENVELOPEOF MOTION::  When we combine the borderWhen we combine the border movements of all the three planes,movements of all the three planes, we get a three-dimensional spacewe get a three-dimensional space within which mandibular movementwithin which mandibular movement is possible.is possible.  This three dimensional limitingThis three dimensional limiting space is called as “Envelope ofspace is called as “Envelope of motion” which was first describedmotion” which was first described byby PosseltPosselt in 1952.in 1952. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 63.
    PROTRUSIVE MOVEMENTPROTRUSIVE MOVEMENT Occurs while incising and grasping food. This movementOccurs while incising and grasping food. This movement occurs after the condyle rotates about 13º in the TMJ. At thisoccurs after the condyle rotates about 13º in the TMJ. At this point the transverse hinge axis shifts to the level of thepoint the transverse hinge axis shifts to the level of the mandibular foramen.mandibular foramen.  The mandible moves forward and downwards. This movementThe mandible moves forward and downwards. This movement is complete when the maxillary and the Mandibular teeth areis complete when the maxillary and the Mandibular teeth are edge to edge.edge to edge. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 64.
    RETRUSIVE MOVEMENTRETRUSIVE MOVEMENT Occurs when the mandible is forcefully moved behind theOccurs when the mandible is forcefully moved behind the centric relation. The patient cannot voluntarilycentric relation. The patient cannot voluntarily reproduce it.reproduce it.  Brought about by the fibers of the temporalis, digastric and theBrought about by the fibers of the temporalis, digastric and the deep fibers of the masseter. The magnitude is 0.5mm.deep fibers of the masseter. The magnitude is 0.5mm. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 65.
    LATERAL MOVEMENTLATERAL MOVEMENT Lateral rotation or laterotrusionLateral rotation or laterotrusion  Bennett movementBennett movement www.indiandentalacademy.comwww.indiandentalacademy.com
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    In the workingside any of the following fiveIn the working side any of the following five movements can take place .movements can take place . www.indiandentalacademy.comwww.indiandentalacademy.com
  • 68.
    BENNETTBENNETT MOVEMENTMOVEMENT  Itis defined as the bodily lateralIt is defined as the bodily lateral movement or lateral shift of themovement or lateral shift of the mandible resulting from themandible resulting from the movement of the condyle alongmovement of the condyle along the lateral inclines along thethe lateral inclines along the mandibular fossae in lateral jawmandibular fossae in lateral jaw movements.movements.  This movement is recorded in theThis movement is recorded in the non workingnon working side .The shift is 1-side .The shift is 1- 4mm.4mm. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 69.
     The Bennettshift is classified based on the timing of the shiftThe Bennett shift is classified based on the timing of the shift in relation to the forward movement of the non workingin relation to the forward movement of the non working condyle.condyle.  Immediate side shift.Immediate side shift.  Precurrent side shiftPrecurrent side shift  Progressive side shiftProgressive side shift www.indiandentalacademy.comwww.indiandentalacademy.com
  • 70.
    IMMEDIATE SIDE SHIFTIMMEDIATESIDE SHIFT www.indiandentalacademy.comwww.indiandentalacademy.com
  • 71.
    PRECURRENT SIDE SHIFTPRECURRENTSIDE SHIFT www.indiandentalacademy.comwww.indiandentalacademy.com
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    PROGRESSIVE SIDE SHIFTPROGRESSIVESIDE SHIFT www.indiandentalacademy.comwww.indiandentalacademy.com
  • 73.
     Bennett MovementBennettMovement has 3 attributes:has 3 attributes:  AmountAmount  TimingTiming  DirectionDirection www.indiandentalacademy.comwww.indiandentalacademy.com
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    BALKWILL’S MOVEMENTBALKWILL’S MOVEMENT Although Bennett has described about this movementAlthough Bennett has described about this movement which became popularly known as Bennett movement, thewhich became popularly known as Bennett movement, the original discovery of this movement should go tooriginal discovery of this movement should go to BALKWILLBALKWILL..  As early as 1870As early as 1870 BALKWILLBALKWILL observed that theobserved that the mandible opened and closed on an axis that runs through themandible opened and closed on an axis that runs through the condyles, that the condyles move downwards and forwards incondyles, that the condyles move downwards and forwards in protrusion and also the mandible moves bodily from side toprotrusion and also the mandible moves bodily from side to side.side. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 77.
    STRUCTURES CONTROLLINGSTRUCTURES CONTROLLING MANDIBULARMOVEMENT:MANDIBULAR MOVEMENT:  The structures controlling Mandibular movement are dividedThe structures controlling Mandibular movement are divided into two types;into two types;  Posterior controlling factorsPosterior controlling factors  Anterior controlling factorsAnterior controlling factors www.indiandentalacademy.comwww.indiandentalacademy.com
  • 78.
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    Intra border movements:Intra border movements : These movements occur within theThese movements occur within the envelope of motion.envelope of motion. They areThey are of two types namelyof two types namely  Functional movementFunctional movement  ParafunctionalParafunctional movementsmovements www.indiandentalacademy.comwww.indiandentalacademy.com
  • 80.
    FUNCTIONAL MANDIBULAR MOVEMENTSFUNCTIONALMANDIBULAR MOVEMENTS They are natural and characteristic movements that occursThey are natural and characteristic movements that occurs during mastication, speech and yawning.during mastication, speech and yawning.  Mandibular openingMandibular opening  Mandibular closingMandibular closing  retractionretraction  Lateral movementLateral movement  MasticationMastication  SwallowingSwallowing  SpeakingSpeaking www.indiandentalacademy.comwww.indiandentalacademy.com
  • 81.
    PARAFUNCTIONALPARAFUNCTIONAL MANDIBULAR MOVEMENTSMANDIBULAR MOVEMENTS TheyAre UncharacteristicThey Are Uncharacteristic and Unnatural Movements Likeand Unnatural Movements Like  Bruxism,Bruxism,  ClenchingClenching www.indiandentalacademy.comwww.indiandentalacademy.com
  • 82.
    Bruxism:Bruxism: The neuromuscular reactionto occlusal interference byThe neuromuscular reaction to occlusal interference by seeking them out and grinding on them. When grinding is ofseeking them out and grinding on them. When grinding is of transient nature, it is called parafunctional grinding whereastransient nature, it is called parafunctional grinding whereas chronic destructive habit may be referred as bruxism.chronic destructive habit may be referred as bruxism. Clenching:Clenching: It is defined as forceful clamping together of jaws in staticIt is defined as forceful clamping together of jaws in static relationship. Considerable amount of force is maintained forrelationship. Considerable amount of force is maintained for several seconds or even longer.several seconds or even longer. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 83.
    METHODS OF STUDYINGMETHODSOF STUDYING MANDIBULAR MOVEMENTMANDIBULAR MOVEMENT  Mandibular, particularly condyle, activities has been studiedMandibular, particularly condyle, activities has been studied for many years by a variety of methods ranging from directfor many years by a variety of methods ranging from direct clinical observations to sophisticated electronic instruments.clinical observations to sophisticated electronic instruments.  1896. Warber used facial clinometer to measure mandibular1896. Warber used facial clinometer to measure mandibular movements.movements.  1908. Bennet traced the pathway of light positioned the1908. Bennet traced the pathway of light positioned the condyle.condyle.  1931. Hildebrand recorded condyle movements by Roentgen1931. Hildebrand recorded condyle movements by Roentgen fluoroscopy.fluoroscopy. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 84.
     Recently usedareRecently used are  direct examination: based on examination of facets anddirect examination: based on examination of facets and wear patternswear patterns  cinematographic techniques: by using motion picturescinematographic techniques: by using motion pictures  cine –radiological studies: use serial tracings of successivecine –radiological studies: use serial tracings of successive frames of filmframes of film  pantography: it is one of the best methods of studyingpantography: it is one of the best methods of studying mandibular movementsmandibular movements www.indiandentalacademy.comwww.indiandentalacademy.com
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    mechanical pantography:mechanical pantography: theseare devices containing two facebows one fixed to maxillathese are devices containing two facebows one fixed to maxilla and other fixed to mandible. One holds writing device andand other fixed to mandible. One holds writing device and other holds recording tableother holds recording table in pantography proceduremovements are recorded inin pantography proceduremovements are recorded in three planes- horizontal, frontal, sagittalthree planes- horizontal, frontal, sagittal these were developed by mac collum and stuart (1955)these were developed by mac collum and stuart (1955) disadvantages-disadvantages- require complex handling procedures in clinics and laboratoryrequire complex handling procedures in clinics and laboratory size and weight are cumbersomesize and weight are cumbersome electronic pantographyelectronic pantography : by hobo and takayama: by hobo and takayama measures right and left eccentric movements by means of smallmeasures right and left eccentric movements by means of small opto- electronic sensor fixed to the maxilla.opto- electronic sensor fixed to the maxilla. www.indiandentalacademy.comwww.indiandentalacademy.com
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    55.ultrasonic instruments.ultrasonic instruments 6.6.electronic instrumentselectronic instruments 77. photoelastic technique. photoelastic technique 8.8. light emitting diodelight emitting diode 99. computer- monitered radionuclide tracings.. computer- monitered radionuclide tracings. www.indiandentalacademy.comwww.indiandentalacademy.com
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    REVIEW OF LITERATURE:REVIEWOF LITERATURE: Michael gardener did a study on voluntary mandibularMichael gardener did a study on voluntary mandibular lateral translation concerning its existence, magnitude, andlateral translation concerning its existence, magnitude, and timing and concluded all subjects showed evidence oftiming and concluded all subjects showed evidence of mandibular lateral translation. New definitions for timing ofmandibular lateral translation. New definitions for timing of mandibular lateral transition are proposed. Of the tracings, 64%mandibular lateral transition are proposed. Of the tracings, 64% exhibited as early translation, 30 % as intermediate, 4 % as lateexhibited as early translation, 30 % as intermediate, 4 % as late mandibular translation.mandibular translation. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 89.
    Jack D prestondid a study on reassessment of mandibularJack D preston did a study on reassessment of mandibular transverse horizontal axis theory and concluded that a singletransverse horizontal axis theory and concluded that a single transverse horizontal axis can usually appear to be located.transverse horizontal axis can usually appear to be located. Location of kinematic axis is a worth while clinical procedureLocation of kinematic axis is a worth while clinical procedure to transfer an arc of rotation in the saggital plane from theto transfer an arc of rotation in the saggital plane from the patient to an articulator. The anatomic asymmetries of the axispatient to an articulator. The anatomic asymmetries of the axis transfer procedure may result in cast dislocations that maytransfer procedure may result in cast dislocations that may produce undesirable alterations in esthetic tooth positions.produce undesirable alterations in esthetic tooth positions. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 90.
    Marta , Lucianadid a model to simulate the masticationMarta , Luciana did a model to simulate the mastication motion at the temperomandibular joint and concluded thatmotion at the temperomandibular joint and concluded that although most mandibular functions involve only a smallalthough most mandibular functions involve only a small range of mouth opening, the maximal position that jaw canrange of mouth opening, the maximal position that jaw can reach at frontal, saggital, lateral planes produce a widereach at frontal, saggital, lateral planes produce a wide range of movements ( upto 6 degrees of freedomrange of movements ( upto 6 degrees of freedom considering the sliding of jaw condyles)considering the sliding of jaw condyles) www.indiandentalacademy.comwww.indiandentalacademy.com
  • 91.
    Warren c rivera,barrym goldman, and Richard s made aWarren c rivera,barry m goldman, and Richard s made a simplified technique to measure mandibular range of motionsimplified technique to measure mandibular range of motion in which tongue blade is used to mark and measure maximumin which tongue blade is used to mark and measure maximum opening and eccentric movements which is more accurate thanopening and eccentric movements which is more accurate than other techniques proposed for the same purpose. Because of itsother techniques proposed for the same purpose. Because of its low cost, convenience, and ease of use the tongue bladelow cost, convenience, and ease of use the tongue blade technique is more practical way to document range of motiontechnique is more practical way to document range of motion than mandibular kinesiograph.than mandibular kinesiograph. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 92.
    Jill k Rendell,Thomas gay did a study on denture adhesiveJill k Rendell, Thomas gay did a study on denture adhesive on mandibular movement during chewing and concludedon mandibular movement during chewing and concluded that use of denture adhesive increased the mean chewingthat use of denture adhesive increased the mean chewing rate in test subjects immediately after and at two and fourrate in test subjects immediately after and at two and four hours after denture adhesive was applied these findingshours after denture adhesive was applied these findings show that using a denture adhesive promotes a faster andshow that using a denture adhesive promotes a faster and more natural rate of chewingmore natural rate of chewing www.indiandentalacademy.comwww.indiandentalacademy.com
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    conclusionconclusion ““ the articulationof human teeth is not athe articulation of human teeth is not a simple thing, no single factoris dominant. all of thesimple thing, no single factoris dominant. all of the interrelated factors are covered and are expressed ininterrelated factors are covered and are expressed in articulating surfaces of teeth. These practices and proceduresarticulating surfaces of teeth. These practices and procedures which neglect anyone factor are doomed to failure”.which neglect anyone factor are doomed to failure”. ( mac collum and staurt )( mac collum and staurt ) www.indiandentalacademy.comwww.indiandentalacademy.com
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