Occlusion /certified fixed orthodontic courses by Indian dental academy

OCCLUSION
IN
OPERATIVE DENTISTRY
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com


CONTENTS


INTRODUCTION



POSTERIOR OCCLUSION



GENERAL DESCRIPTION



ROLE OF CONTACT AREAS



GOALS FOR COMPLETE DENTISTRY



ROLE OF CONTOUR



RESPONSE TO HIGH RESTORATION



ROLE OF MARGINAL RIDGES



OCCLUSAL DISEASE



SIGNS OF INSTABILITY OF OCCLUSION



TMJ





MASTICATORY MUSCULATURE

REQUIREMENTS FOR EQILIBRIUM OF
THE MASTICATORY SYTEM



MANDIBULAR MOVEMENT





POSSELT'S MOTION

REQUIREMENTS FOR OCCLUSAL
STABILITY



OCCLUSAL SCHEMES



OCCLUSAL EQUILIBRATION



CENTRIC OCCLUSION



VERIFICATION OF COMPLETION



CENTRIC RELATION



COMPUTER ASSISTED DYNAMIC
OCCLUSAL ANALYSIS



DETERMINING CENTRIC RELATION



DENTITION – OCCLUSAL EXAMINATION



LOAD TESTING OF TMJ‟S





RECORDING CENTRIC RELATION

TREATMENT PLANNING
CONFORMATIVE APPROACH



CLASSIFICATION OF OCCLUSION



CONCLUSION



DETERMINANTS OF OCCLUSION



REFERENCES



THE PLANE OF OCCLUSION


INTRODUCTION
 Occlusion literally means “closing”.
 When the jaws are closed and teeth are in contact, this

is termed as “static” occlusion.
 However, occlusion mainly occurs as momentary
contacts during mandibular movements and is termed
as “Dynamic occlusion”.
 “The contact of teeth in opposing dental arches, when
they are in contact (static) and during various jaw
movements (dynamic)” – STURDEVANT.


GENERAL DESCRIPTION
 Blunt, rounded or pointed projections of the

crowns of the tooth - Cusps
 Cusps are separated by distinct Developmental
grooves
 The facial cusps are separated from lingual cusps
by a deep groove - central groove
 If a tooth has multiple facial or lingual cusps, the
cusps are separated by facial or lingual
Developmental grooves
 Depressions between the cusps - Fossae
 Grooves having noncoalesced enamel – Fissures
 Noncoalesced enamel at the deepest point of a

• Operative Dentistry follows the concept of functional

or physiologic occlusion.
• The functional occlusion is one which can function

efficiently without pain & remains in a state of health
regardless of the relationship between the maxillary
and mandibular teeth.
• A dental examination is complete if it identifies all

factors that are capable of causing or contributing to
deterioration of oral health or function.

GOALS FOR COMPLETE
DENTISRTY
 Freedom from disease in all masticatory system

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




structures
Maintaining healthy periodontium
Stable TMJ‟s
Stable occlusion
Maintaining healthy teeth
Optimum esthetics


RESPONSE TO HIGH RESTORATION
 Tooth ache

 Tooth tender on biting
 Tooth wear
 Spastic masticatory muscles
 Muscle tension headache
 Condyle / disk derangement
 Degenerative arthritic changes in the TMJ‟s


OCCLUSAL DISEASE
 Occlusal disease is deformation or disturbance of

function of any structures within the masticatory
system that are in disequilibrium with a harmonious
interrelationship
between
the
TMJ’s,
the
masticatory musculature & the occluding surfaces
of the teeth
 Abrasion : wear due to friction between a tooth and

an exogenous agent
 Erosion : tooth surface loss due to chemical or

electrochemical action
 Abfraction : stress induced non-carious cervical

ATTRITIONAL WEAR
 Attrition : wear due to tooth-to-tooth friction
 Mostly in the lower anterior teeth

 Causes :

1. Deflective incline interferences of
posterior teeth to centric relation
forward slide of mandible during
closure
collision of lower anteriors with
upper
anteriors.
2. Improper restorations on anterior teeth
3. Direct interference of the anterior teeth to
complete closure in centric relation

SPLAYED TEETH
 Forward

movement

of

upper

anteriors
 Cause :
Improperly contoured restorations
that are too thick on the lingual of
upper anteriors or overcontoured
lower restorations.

SENSITIVE TEETH

• Cause :

occlusal overload

pulp hyperemia / noncarious cervical
cracks

TOOTH

SPLIT TEETH / FRACTURED CUSPS
 Cause : interference of cusp incline

with strong occlusal force

PAINFUL MUSCULATURE
• Cause :
Deflective occlusal interference

Disharmony between the occlusion
&TMJ’s

TMJ
 All occlusal analysis starts at the TMJ


 As the TMJ is a stress bearing joint, all of the

articular surfaces of the condyle, the fossa & the
eminence are covered with avascular layers of
dense fibrous connective tissue
 TMJ is nourished by synovial fluids that lubricate the
joint for smooth gliding function
UNDERSTANDING CONDYLE DISK
ALIGNMENT

Medial & lateral Posterior ligament Superior elastic
Diskalwww.indiandentalacademy.com
ligament
stratum

Superior lateral
Pterygoid muscle

 The axial rotation occurs around a

true hinge axis when the condyles
are fully seated.
 Rotation around a fixed horizontal
axis seems improbable because of
angulation of the condylles in
relation to the horizontal axis
 The condyles serve as bilateral
fulcrum for the mandible & so the
joints are always subjected to
compressive forces whenever the
elevator muscles contract.

MASTICATORY MUSCULATURE
 Muscles of mastication : Masseter

Temporalis
Lateral /
External pterygoid
Medial / Internal pterygoid


MANDIBULAR MOVEMENT
 Centric relation (CR) is the position of the mandible when the

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

condyles are positioned superiorly in the fossae in healthy
TMJs.
This position is independent of tooth contacts.
Rotation with the condyles positioned in CR is termed terminal
hinge (TH) movement.
TH is used in dentistry as a reference movement for
construction of restorations.
Initial contact between teeth during a TH closure provides a
reference point, termed centric occlusion (CO).
Many patients have a small slide from CO to MI, typically in a
forward and superior direction.

 Maximum rotational opening in TH is 25 mm

measured between the incisal edges of the
anterior teeth
 Simultaneous, direct anterior movement of


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



both condyles, or mandibular forward
thrusting, is termed protrusion.
The mandible can protrude approximately 10
mm.
complex motion combines rotation and
translation in a single movement.
Most mandibular movement during speech,
chewing, and swallowing consists of both
rotation and translation.
Maximum opening is approximately 50 mm.

 Lateral movement is often described with respect to only one

side of the mandible for the purpose of defining the relative
motion of the mandibular to the maxillary teeth.
 Mandibular pathways directed away from the midline are
termed working (laterotrusion & function), and
mandibular pathways directed toward the midline are termed
nonworking (mediotrusion, nonfunction & balancing).
 Lateral movement is approximately 10 mm.


Bennet movement :
 The rotation of the working side condyle in it‟s
articular fossa results in a slight lateral movement of
the condyle.
This lateral movement of
the condyle
averages „1 mm‟ in
extent and is termed
the “Bennet
movement” or the
„immediate
side shift.‟
 This movement may be straight lateral,
lateral and anterior; lateral and distal;
lateral and superior or lateral and inferior.
Bennet angle:
 The mean angle formed by the sagittal plane and
thewww.indiandentalacademy.com
path of the non-working condyle as viewed in the
horizontal plane is termed the “Bennet angle”.

POSSELT'S MOTION
 In 1952, Posselt described the capacity of motion of the mandible. The resultant

diagram has been termed Posselt's motion (known as the “Envelope of
motion”).
 The path of the mandible during its movement in each of the possible three
directions (sagittal, horizontal & vertical) is described to points beyond which
the mandible is not capable of further movement.
 These points are defined as the border limitation of mandibular movements, and
moving the mandible to these points is therefore called “border movements of
the mandible”.
Centric relation
Centric occlusion
Protrusion

Hinge movement
(terminal arc of opening)


max. jaw opening

OCCLUSAL SCHEMES
Three basic schemes of occlusion : Balanced
occlusion
Canine protected occlusion
Group function occlusion

BALANCED OCCLUSION

 It is defined as “the simultaneous, bilateral contacting of

maxillary and mandibular teeth in anterior & posterior
occlusal areas in centric and eccentric positions
 This concept was applied to restoration of natural
dentition by
Mc Collum & Schuyler et.al.,
 Seen in case of advanced attrition case
 In natural teeth, balancing side contacts are inappropriate
and potentially harmful as they constitute premature
contacts and were proposed to cause occlusal wear, pdl
breakdown, & TMJ disturbances.

CANINE PROTECTED OCCLUSION




As the muscles move the mandible to the
working side, the tip or the distobuccal
incline of the lower working side canine
glides down the palatal incline of the
upper working side canine.
This causes the mandible to move laterally, forwards and
to open. This is termed „Canine guidance‟ & the concept of
occlusion as „Canine protected occlusion‟

On a canine guided working movement the premolars &
molars on the working side become separated as the mandible
moves away from centric occlusion.
 All the teeth on the non-working side also become separated
as thewww.indiandentalacademy.com
mandible moves away from centric occlusion.

UNILATERAL BALANCED / GROUP FUNCTION
OCCLUSION
 There is simultaneous gliding contact of teeth on

the lateral & protrusive side during lateral &
protrusive movement.
 Group function is seen on all the working side
teeth.
 The incisal edges of the' mandibular anterior teeth
glide down the palatal surfaces of the maxillary
anterior teeth.
 The buccal inclines of the buccal cusps of the mandibular premolars and
molars glide against the palatal inclines of the buccal cusps of the maxillary
premolars and molars.
 Tooth guided working guidance continues until the guiding teeth on the
working side meet in an edge to edge relation.
 Further movement towards the working side is guided by contact of the
upper and lower incisors. This is termed 'cross over'.

CENTRIC OCCLUSION
 It is the position of maximum intercuspation of

teeth which is in harmony with the neuromuscular
mechanism.
 This is not the most retruded position of the
mandible


 Centric occlusal contacts should be checked in both functional &

non-functional occlusion.
 Functional occlusion occurs in the segments of arch toward which the

mandible moves & is divided into lateral functional & protrusive functional
occlusion
 Lateral functional occlusion is predominantly guided by canines but

involves sharing of contact by other posterior teeth in the functional working
segment
 Facial range – Mn Facial cusps moving facially & distally across
the lingual inclines of Mx Facial cusps
 Lingual range – Mx Palatal cusps moving across the
facial inclines of Mn lingual cusps
 In Protrusive functional occlusion, all Mn anterior teeth will contact along

the palatal inclines of Mx anterior teeth with the disclussion of posterior
teeth

 Non functional occlusion or balancing contacts are undesirable in the natural

dentition.
 Non functional occlusion is divided into lateral non-functional & protrusive
non-functional occlusion
 In lateral non-functional occlusion,

the Mn facial cusps on the non-functioning side move obliquely, lingually &
mesially towards the Mx palatal cusps along their facial inclines
 Protrusive non-functional occlusion occurs in facial & lingual range
 The facial range of Protrusive non-functional occlusion occurs when the

mesial cusp ridges of Mn facial cusps contact the distal slopes of triangular
ridges of Mx facial cusps
 The lingual range of Protrusive non-functional contact occurs when the distal
cusp ridges of Mx palatal cusps contact the mesial slopes of triangular ridges
of Mn lingual cusps.

POTENTIAL CONTACT AREAS OF
OCCLUSAL SURFACES
MAXILLARY
POSTERIOR

MANDIBULAR
POSTERIOR

ZONE 1

Facial range in Lateral
functional contact

Lingual inclines of facial
cusps

Facial inclines of facial
cusps

ZONE 2

Facial range in Centric
contact

Central groove area

Facial cusp tips

ZONE 3

Lateral non-functional
contact

Facial inclines of palatal
cusps

Lingual inclines of facial
cusps

ZONE 4

Lingual range in Centric
contact

Lingual cusp tips

Central groove area

ZONE 5

Lingual range in Lateral
functional contact

Lingual inclines of palatal
cusps

Facial inclines of lingual
cusps


CENTRIC RELATION
 Centric Relation Is the relationship of








the mandible to the maxilla when the
properly
aligned
condyle-disc
assemblies are in the most superior
position against the eminentiae
irrespective of vertical dimension or
tooth position
Centric relation refers to both position
& condition can freely condyle-disk fixed axis in centric
The condyles of the rotate on a
assemblies. 20 mm of jaw opening with out moving out of
relation upto
fully seated position in their respective fossa.
Centric relation is an interference-free occlusion.
The rotating condyles are free to move
down & up the eminence to & from
centric relation, permitting the jaw to
open or close at any position from centric
relation to most protruded.

DETERMINING CENTRIC RELATION /
ADAPTED CENTRIC POSTURE
PROCEDURE – BILATERAL MANIPULATION

1 . Recline the patient all
the way back



the way back


2 . Head stabilization


the way back



3 . Stretch the neck by lifting
the patient‟s chin


the way back

4 . Place the four fingers on
lower border of the mandible




the way back



4 . Place the four fingers on 5 . Bring the thumbs together
lower border of the mandible to form a „c‟ with each hand


the way back



4 . Place the four fingers on 5 . Bring the thumbs together 6 . With a very gentle touch,
manipulate the jaw so it
lower border of the mandible to form a „c‟ with each hand
slowly hinges open and

DIRECTLY FABRICATED
ANTERIOR DEPROGRAMMING
DEVICE


DIRECTLY FABRICATED
DEVICE


THE PANKEY JIG
Dr. Keith Thornton

DIRECTLY FABRICATED
DEVICE


THE PANKEY JIG
Dr. Keith Thornton

THE BEST-BITE APPLIANCE

DIRECTLY FABRICATED
DEVICE

THE PANKEY JIG
Dr. Keith Thornton

THE LUCIA JIG
Lucia, Dr.Peter Neff



DIRECTLY FABRICATED
DEVICE

THE PANKEY JIG
Dr. Keith Thornton

THE LUCIA JIG
Lucia, Dr.Peter Neff



Leaf Gauge
Dr.Hart

LOAD TESTING OF TMJ‟S
 Not done to force the condyle into centric relation





done to check centric relation
Done in increments
Any sign of pain – condyle on affected side is not
fully seated
Reasons for tenderness : Intracapsular disorder
Occlusal interferences
Mistakes done during load testing :
Applying too much pressure too soon
Not applying enough upward loading force

RECORDING CENTRIC RELATION
CRITERIA FOR ACCURACY IN MAKING AN
INTEROCCLUSAL BITE RECORD
 The bite record must not cause any movement of teeth or
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


displacement of soft tissue.
It must be possible to verify the accuracy of the interocclusal
record in the mouth
The bite record must fit the casts as accurately as it fits the
mouth
It must be possible to verify the accuracy of the bite record
on the casts.
The bite record must not distort during storage or
transportation to the laboratory

WAX BITE RECORD
 Most popular method.
 Delar wax – thick at front
 Technique :


ANTERIOR STOP TECHNIQUE


CLASSIFICATION OF OCCLUSIONS
ANGLE‟S CLASSIFICATION


INTERARCH TOOTH RELATIONSHIPS
 In normal Class I occlusion, the mandibular facial

cusp contacts the maxillary premolar mesial
marginal ridge and the maxillary premolar lingual
cusp contacts the mandibular distal marginal
ridge. Because only one antagonist is contacted,
this is termed a tooth-to-tooth relationship.
 The most stable relationship results from the
contact of the supporting cusp tips against the two
marginal ridges, termed a tooth-to-two-tooth
contact.
 In Class II occlusion, each supporting cusp tip
will occlude in a stable relationship with the
opposing mesial or distal fossa; this relationship is
a cusp fossa contact.

DAWSON‟S CLASSIFICATION
Type I : Maximal intercuspation is in harmony with centric relation
 Centric relation is verifiable with the teeth separated.

 Jaw can close to maximal intercuspation without premature

tooth contacts

Type IA : Maximal intercuspation occurs in harmony with adapted
centric posture
 Adapted condition to – Intracapsular deformation
 TMJ‟s can accept loading with no discomfort


TYPE II : Condyles must displace from a verifiable centric relation
for maximum intercuspation to occur

TYPE IIA : Condyles must displace from an adapted centric
posture for maximum intercuspation to occur
 The source of pain will be in muscle or in interfering tooth
 The occlusal therapy goal is to achieve Type I or IA


TYPE III: Centric relation can not be verified
 TMJ‟s cannot accept loading without tenderness
 Focus should be on correcting the TMD before occlusal
treatment can be finalised
 The occlusal therapy goal is to achieve Type I or IA
TYPE IV : The occlusal relationship is in an active stage of
progressive disorder because of pathologically unstable TMJ’s
 Actively progressive disorder of the TMJ’s
 Signs : progressive anterior open bite
progressive asymmetry
progressive mandibular retrusion
 The goal is to stop the progression of the TMJ’s defprmation


DETERMINANTS OF OCCLUSION
 FIRST DETERMINANT OF OCCLUSION : Condylar

path
 SECOND DETERMINANT OF OCCLUSION : Anterior
guidance

 In www.indiandentalacademy.com
a perfected occlusion, the combination of both

Condylar guidance & Anterior teeth guidance

CONDYLAR GUIDANCE
 It refers to the path that the horizontal rotational axis of

the condyles travel during normal mandibular opening.
 It includes : Translation of condyles
Bennett shift
Inter-condylar distance

TRANSLATION OF CONDYLES
 Both the condyles translate simultaneously along their

eminences in protrusive functional movement.
 In lateral functional movements, the condyles on nonfunctional side translates forward along the eminence
while the condyle on working side rotates in its fossa.

BENNETT SHIFT
 Bennett shift is the lateral bodily shift of the

mandible towards the working side in function.
 The amount of lateral shift influences the pattern
of tooth contact during lateral movement.
INTER-CONDYLAR DISTANCE
 The inter-condylar distance affects the path of

lateral functional movement of mandible since it
determines the location of vertical axis of rotation
in relation to mandibular arch.
 The farther the condyles are from midsaggital
plane, the more anterior is the path of lateral
excursion and vice versa.

ANTERIOR GUIDANCE
 When restoring upper anterior teeth, the lingual

contours must be in harmony with the envelope of
function from centric relation contact to incisal edge
positions.
 In Restorative treatment, restriction of the envelope
of function is the most problematic.
 Restorations must be in hormany with the envelope
of function
 Incisal edges too far
 Incisal edges too far
back
forward


Lower incisal edges
Determination of horizontal Determination of horizontal
definite labio-incisal line angle
Position for upper incisal edgesposition for lower incisal
edges

Exact position & contour of incisal
edge

Determination of contour of the anterior
guidance

THE PLANE OF OCCLUSION
 It is an imaginary surface that theoretically touches

the incisal edges of the incisors and the tips of the
occluding surfaces of the posterior teeth.
 The curvatures of posterior plane of occlusion are
divided into :
Curve of Spee
Curve of Wilson


CURVE OF SPEE
 Antreroposterior curvature of the occlusal surface,

beginning at the tip of lower canine & following
the
buccal cusp tips of bicuspids & molars
and continuing
to the anterior border of
ramus
 If the curved line continues further back, it would
follow an arc through the condyle, with a 4 inch
radius
 The curve results from variations in axial alignment
of the lower teeth parallel with its arc of closure.
This requires the last molar to be
inclined at the greatest angle & the forward tooth to
be at the least angle
 It iswww.indiandentalacademy.com
designed to permit protrusive disclusion of the

CURVE OF WILSON
 Mediolateral curve that contacts the buccal &
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



lingual cusp tips on each side of the teeth.
Alignment of posterior teeth to parallel the
direction of loading from the internal
pterygoid muscle results in curve of wilson
Results from inward inclination of lower
posterior teeth & outward inclination of upper
posterior teeth
The inward inclination of lower occlusal table
is designed for direct access from the
lingual, with no blockage by lower lingual
cusps
The outward inclination of upper occlusal
table provides access from the buccal for the
food to be tossed directly onto occlusal table

 When the curve of wilson is made too flat, ease of

masticatory function may be impaired because of
increased activity required to get the food onto
the occlusal table.
 The design of lower posterior teeth moving

downward before they shifting medially is made
possible by the curve of wilson.


POSTERIOR OCCLUSION
Posterior teeth (cusp characteristics):
 For teeth to remain stable there must be certain barriers against
their displacement. These barriers are provided by the vertical
overlaps of the teeth (occluso-apically by the opposing teeth)
and mesio-distally by the contact areas.
 This is achieved by a

Holding cusps/supporting cusps/stamp cusp/centric cusps
Non-holding cusps/non-centric/non-supporting cusps


Supporting cusps : these cusps contact the opposing teeth
along the central fossa occlusal line. For upper posterior teeth
in normal occlusion, these supporting cusps are usually the
lingual cusps occluding in opposing fossae while for lower
posterior teeth, they are usually the buccal cusps.
During fabrication of restorations
it is important that supporting cusps do
not contact the opposing teeth in
manners that result in lateral
deflection; rather contacts should be on
smoothly concave fossae so that forces
are directed approximately parallel to
the long axis of the teeth.

 Non-supporting cusps /Guiding cusps:

These cusps do not contact the tooth and are usually
located in the embrasures or developmental grooves of
opposing teeth
 They have sharper cusp ridges and form a separation

between the soft tissues and occlusal table.


Posterior Tooth Contacts :
 In idealized occlusal designed for restorative dentistry, the
posterior teeth should contact only in MI.
 Forceful contact or collisions of individual posterior tooth
cusps during chewing and clenching may lead to patient
discomfort or damage to the teeth.
 During chewing the working-side closures start from a
lateral position and are directed medially to MI.
 Test movements are used by dentists to assess the occlusal
contacts on the working side; for convenience, these
movements are started in MI and move laterally.
 Thus the working-side test movement follows the same
pathway as the working-side chewing closure but occurs
in the opposite direction.

 The preferred occlusal relationship for restorative purposes

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





is to limit the working-side contact to the canine teeth.
Tooth contact posterior to the canine on the working side
may occur naturally in worn dentitions.
Multiple tooth contacts during lateral jaw movement are
termed group function.
Group function occurs naturally in a worn dentition;
however, group function can be a therapeutic goal when the
bony support of the canine teeth is compromised by
periodontal disease.
During chewing closures, the mandibular teeth on the
nonworking side close from a medial and anterior position
and approach MI by moving laterally and posteriorly.
Avoidance of contacts on the nonworking side is an
important goal for restorative procedures on the molar teeth.

ROLE OF CONTACT AREAS
 A break in continuity of the line of contact areas throws

additional responsibility on the PDL & alveolar bone.
 Creating a contact that is too broad, bucco-lingually or
occluso-gingivally in addition to changing the tooth
anatomy will change the anatomy of the inter dental col.
 The broadened contact produces an inter-dental area that
the patient is less able to clean i.e. increases the area
susceptible to future decay.
 Creating a contact that is too narrow bucco-lingually or
occluso-gingivally leads to greater susceptibility for
microbial plaque accumulation & predisposes to the
periodontal and caries problems.

ROLE OF CONTOUR
 All tooth crowns exhibit contours in the form of convexities

and concavities which should be reproduced in a restoration.
 The concavities occlusal to the height of contour, whether
they occur on anterior or posterior teeth are involved in the
occlusal static and dynamic relations as they determine the
pathways for mandibular teeth into and out of centric
occlusion.
 Deficient or mislocated concavities will lead to premature
contacts during mandibular movements, which could inhibit
the physiologic capabilities of these movements.
 Excessive concavities can invite extrusion, rotation or
tilting of occluding cuspal elements into non-physiologic
relations with opposing teeth.

ROLE OF MARGINAL RIDGES
A marginal ridge should always be formed in two planes buccolingually, meeting at a very obtuse angle. This feature is essential when
an opposing functional cusp occludes with the marginal ridge.
A marginal ridge with these specifications is essential for;
1. The balance of the teeth in the arch.
2. Prevention of food impaction proximally.
3. Protection of the periodontium.
4. Prevention of recurrent and contact decay.
5. For helping in efficient mastication.

SIGNS OF INSTABILITY OF OCCLUSIION
 Excessive wear
 Hypermobility of one or more teeth
 Migration of one or more teeth – Horizontal shifting

Intrusion
Supraeruption


REQUIREMENTS FOR EQILIBRIUM OF THE
MASTICATORY SYTEM
 Stable TMJ‟s even when loaded
 Anterior guidance in harmony with functional

movements of the mandible
 Noninterference of posterior teeth
in centric occlusion
posterior
disclusion
when
condyle leaves CR
 All teeth in vertical harmony with the masticatory
muscles
 All teeth in horizontal harmony with the neutral
zone

REQUIREMENTS FOR OCCLUSAL STABILITY
 Stable stops on all teeth when the condyles are in centric relation
 Anterior guidance in harmony with the border movement of the
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



envelope of function
Disclusion of all posterior teeth in protrusive movements
Disclusion of all posterior teeth in nonworking side
Noninterference of all posterior teeth on working side, with either the
lateral anterior guidance or the border movements of the condyle.
In lateral movements, supporting cusps preferably should have slight
freedom in centric and occlude in a valley like space on opposing
teeth (in grooves or embrasures), to facilitate non interfering passage
of cusps.
During protrusive movements, there should not be any tooth contact
posteriorly.

OCCLUSAL EQUILIBRATION
 Reduction of all contacting tooth surfaces that

interfere with the completely seated condylar
position i.e., centric relation
 Selective reduction of tooth structure that interferes
with lateral excursions
 Elimination of the posterior tooth structure that
interferes with protrusive excursions.
 Harmonization of the anterior guidance


VERIFICATION OF COMPLETION
 Clench test :

Clenching the tooth together & squeezing firmly.
Reasons for discomfort : incomplete elimination of
occlusal interferences on the posterior teeth


COMPUTER ASSISTED DYNAMIC
OCCLUSAL ANALYSIS
T – scan
 Developed by Maness.
 Sensor unit that records occlusal contacts on a thin
mylar film & relays the information to a computer


DENTITION – OCCLUSAL EXAMINATION
 The occlusal contacts on teeth can be located by marking

them with articulating paper or ribbon held by Miller‟s
forceps.
 Shim stock or Mylar strips are also helpful in identifying the
presence of occlusal contacts.


The examination of the occlusion is performed in three steps:
1. First, the teeth need to be dry and one of the easiest ways
of doing this is to ask the patient to close onto folded tissue
paper held by Miller forceps.
2. Mark-up the patient's dynamic
occlusion, by asking the patient to slide
his/her teeth from side-to-side whilst
holding the articulating paper (Blue paper)
between them.
3. The final stage requires changing the
colour of the paper (Red) and asking the
patient to tap his/her teeth' together into a
normal bite. This will mark the static
occlusion.

TREATMENT PLANNING
CONFORMATIVE APPROACH
 Before initiating treatment the practitioner must decide

whether to provide restorations within the existing occlusal
scheme or to change it deliberately.
 Conformative approach is defined as the provision of
restorations „in harmony with the existing jaw relationships‟.
 It is the principle of providing a new restoration that does
not alter the patient‟s occlusion
 Majority of restorations follow this principle.
 “The provision of new restorations to a different occlusion
which is defined before the work is started: i.e. „to visualize
the end before starting‟ is defined as the re-organized
approach.”

TECHNIQUE
 When considering the provision of simple restorative

dentistry to the conformative approach, no matter
what type of occlusal restoration is being provided
the sequence is always the same - THE ‘EDEC
PRINCIPLE’.

 The EDEC Principle is useful in relation to:

- Direct restorations
-www.indiandentalacademy.com
Indirect restorations

THE EDEC PRINCIPLE FOR DIRECT
RESTORATIONS
1. Examine:
 Examine the static and dynamic occlusions before
picking up a handpiece.
 Mark them pre operatively on teeth, as explained
earlier.
 Malpositioned opposing supporting cusps, ridges or
fossae may be recontoured in order to achieve optimal
occlusal contacts in the restored tooth.
 Plunger cusps and over erupted teeth are to be
reduced.
 In anterior restorations, the scheme of incisal
guidance must be examined and understood prior to
tooth preparation.
 Also, an assessment of periodontal condition must be
made.

2. Design:
 Always visualize the design of the cavity
preparation. This is better done after a simple
occlusal examination .
 The existing occlusal marks will either be
preserved by being avoided in the preparation,
or they will be involved in the design, but never
end preparation margins at these points.
3. Execution:
 The execution of the restoration must be to the design (form) of
the preparation that the dentist will have decided before starting
to cut.
 Controlled interproximal cutting and care in restoring axial tooth
contour to avoid overcontouring is essential.
 Carving of restorations must be harmonious to occlusion and
should not introduce premature contacts.

4. Check:
 Finally, check the occlusion of the
restoration, that it does not prevent all the
other teeth from touching in exactly the
same way as they did before. This is either
done by;
 This is done by reversing the colour of the
paper or foils used pre-operatively and
using the preoperative marks as a reference.


THE EDEC PRINCIPLE FOR
INDIRECT RESTORATIONS
 The dentist not only has to examine the occlusion in

Indirect restorations but the results of that examination
have to be accurately recorded and that record has to be
transferred to the technician.
 The EDEC principle followed for indirect restorations


1. Examine:
 The examination of the patient‟s pre-existing occlusion is carried
out in exactly the same way as described for the direct restoration.
 There is a need for this information to be transferred accurately

to the laboratory technician; hence a record must be made.
 The methods of recording interocclusal records include:


Two dimensional bite records – Intra oral photographs,
written records, and/or Occlusal Sketching



Three dimensional bite records – Bite registration

materials such as hard wax, acrylic resin, elastomers etc


A combination of both.

2. Design:
 Clinically the cavity preparation is designed in exactly the
same way as for a direct restoration.
 The fundamental difference is that , the technician is going to
make the restoration.
3. Execute:
 From an occlusal point of view one of the most significant
considerations is the provision of a temporary restoration
which duplicates the patient's occlusion and is going to
maintain it for the duration of the laboratory phase.
 For this the temporary restoration should:
be a good fit, so that it is not going to move on the tooth;
provide the correct occlusion, so that the prepared tooth
maintains its relationships;
be in the same spatial relationship with adjacent and
opposing teeth.

4. Check:
 The occlusion of the restoration should be as ideal
as possible (preferably not on an incline) and should
not prevent all the other teeth from touching in
exactly the same way as they did before. This needs
to be checked before and after cementation.


CONCLUSION
 Occlusion is fundamental to the practice of dentistry, in

providing a biologically functional restoration and for
comprehensive patient care.
 A dental restoration after being attached to the tooth
becomes one of the essential components of the
stomatognathic system. Hence, any restoration (from
intracoronal direct restoration to complex crown and
bridge work) must be planned to conform to the existing
occlusal pattern and not to disturb it

REFERENCES
 WHEELER‟S Dental Anatomy, Physiology & Occlusion

7th edition
 PETER E. DAWSON Functional Occlusion
 STURDEVANT‟S Art & Science of Operative Dentistry

5th edition
 M.A. MARZOUK Operative Dentistry modern theory and

practice
 S J Davies et.al., - Occlusion: Good occlusal practice in simple

restorative dentistry.
British Dental Journal (2001) 191, 365 - 381

Thank you
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