Occlusion part ii /certified fixed orthodontic courses by Indian dental academy

INDIAN DENTAL ACADEMY
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OCCLUSION (PART II)


CONTENTS
1. Concepts of occlusion
2. Optimum orthopaedically stable joint
position
3. Optimum functional tooth contacts
4. Normal versus ideal occlusion

5.Criteria for
occlusion

Optimum

functional

6.Occlusal contact patterns
a) Canine guided occlusion
b) Group function occlusion
7. Summary
8. References

“What is the best functional
relationship or occlusion of the
teeth” ?


Concepts of occlusion
Three occlusal concepts:
The Gnathological
The Freedom-in-centric
European conceptual model


THE GNATHOLOGICAL
CONCEPT

•Mid 1920’s McCollum.
Gnathology: exact science of
mandibular movement and resultant
occlusal contacts.
Instruments:
• Kinematic face bow, Gnathoscope
and Gnathograph

Balanced
occlusion:(complete
dentures)
“During functional excursions there
is multiple simultaneous contacts
present both on the working side
and on the balancing side”
Stallard and Stuart: organic or
organised occlusion.
-neglected that mastication is more
vertical than lateral.

ARNE G. LAURITZEN
Direction of occlusal stresses-long axis of
teeth.
 Centric relation=centric occlusion
(condyles in uppermost and rearmost
position)
Simultaneous occlusal loads fall on as
great number of teeth.
Lateral excursion may be free.
Canine guided occlusion.
Group contact between upper and lower
anterior teeth during protrusive movement.

NILES GUICHET AND GNATHOLOGY
Optimal occlusion (1966)
Canine guided occlusion- biomechanics
Occlusion must be in harmony with the
mandibular movements of each patient.
Ganathograph and Pantograph.
Denar articulator.

 There is horizontal movement of the
mandible
from
the
maximal
intercuspal position and teeth are
capable of standing that horizontal
stress in function .
 (D’ Amicos)-canines - eight times
stress than on the 2nd premolars.


VISION OF TRANSOGRAPHIC CONCEPT
Page’s
Four principles:
1. Opening axis
2. Cranial plane
3. Bennett movement
4. Envelope of motion
1. Opening axis:12º to 15º of rotation.
Transverse hinge axis –reproducible.

2.Cranial planes:No translatory condyles,
so no practical support for horizontal
plane.
3.Bennett movement: such a movement is
because of mouth opening to 2
noncolinear axes, Page did not concede
to the existence of the Bennett side shift.
4.

In the discussions conceding the
envelope of motion, when one takes the
motions to a narrow functional terminal
orbit, raised a great number of questions
in the oral rehabilitation.

FREEDOM IN CENTRIC
Posselt was first
Functional occlusion- Ramfjord and Ash1970’s
Criteria are to attempt to eliminate the
need for neuromuscular adaptation.
According to this concept,
Maximum intercuspation and centric
relation are coincident but flat areas on the
depth of the fossae, on which opposing

cusps occlude, will allow for a certain
degree of freedom in both centric and
eccentric movements without the guiding
influences of occlusal inclines.
Vertical dimension of occlusion in
maximum intercuspation and centric
relation might be the same when all the
interferences for closing in centric relation
are eliminated.

OCCLUSAL CONCEPTS OF SCHUYLER
Correction of occlusal disharmonies in the
natural dentition and to the concepts of
freedom in centric and incisal guidance.
According to Schuyler,
Freedom in centric is a maxillomandibular
position where maximum intercuspation
and centric relation coincide to a certain
degree of freedom for eccentric excursions
without the influence of occlusal inclines.

Anteroposterior difference – 0.5 to 1
mm
Variation in centric relation recording –
not a point – area in relation to
horizontal plane.
Anterior guidance – Purpose: permit a
condylar motion without restrictions
along with the prevention of posterior
contacts, during lateral excursions

BEYRON’S OCCLUSAL CONCEPTS
Based on functional convenience and
avoidance of discomfort
Most
physiological
inter-relationship
between morphology and function might
be the most natural one.
Neuromuscular
mechanismprotects
teeth – excessive loads – protective
reflex- important role in mandibular
movement patterns.

PANKEY MANN PHILOSOPHY
Monson’s sphere (occlusal line and
plane) + Meyer’s concepts of a
functionally generated path
Pankey
Mann
rehabilitation

Philosophy

–

oral

Objectives:- optimal health, masticatory
efficiency, comfort and esthetics
Recently, Pankey Mann Schuyler concept
(based on group function)

Stable and Static contacts - greatest
number of teeth
Long centric – Occlusal harmony with an
anterior slide between centric relation and
maximum intercuspation (1mm) and a
small amount of lateral freedom for
accommodation of the Bennett movement
on the horizontal plane.
Group function during lateral excursion
(working side)
Balancing side - No contacts
Protrusion – Immediate disocclusion

DAWSON’S CONCEPT
Peter Dawson
 Manipulation of the jaw in centric
relation (Bimanual technique)
 Recording the border movements
(Modification
of
functionally
generated path technique)

Anterior guidance:
 Anterior teeth are more capable of
supporting stress than posteriors:
(a)Position of anteriors
(b)Higher density of bone
(c)Longer roots, better crown : root
ratio.
 Theory of “Nutcracker”

GERBER’S CONDYLAR
DISPLACEMENT THEORY
European concept
“ The normal or ideal occlusion was one
in which the teeth would be in maximum
intercuspation,
with
the
condyles
centered in the articular surfaces in the
median and uppermost position. Any
deviation related to this mandibular
centralization constitutes a condylar
displacement.”

RAMFJORD AND ASH CONCEPTS OF
OCCLUSION
 Equilibrium
between
the
different
components of masticatory system.
 Freedom for condyle movement
 The occlusal concept applied should
promote occlusal stability, does not
exceed the needs and finances of most
persons, is controlled by general clinician
and does not need a specialized
laboratory technician.

Normal versus Ideal occlusion


Optimum orthopaedically stable
joint position
Centric relation, is the position
of the mandible when the
condyles
are
in
an
orthopaedically stable position.

Centric relation

1:The maxllomandibular relationship in
which the condyles articulate with the
thinnest
avascular
portion
of
their
respective disks with the complex in the
anterior–superior position against the
shapes of the articular eminences.This
position is independent of tooth contact.
This position is clinically discernible when
the mandible is directed superiorly and
anteriorly.

It is restricted to a purely rotary
movement about the horizontal axis(GPT5).
2:The most retruded physiologic relation
of the mandible to the maxillae to and
from which the individual can make lateral
movements.It is a condition that can exist
at various degrees of jaw separation.It
occurs
around
the
terminal
hinge
axis(GPT-3).

3:The most retruded relation of he
mandible to the maxillae when the
condyles are in the most posterior
unstrained position in the glenoid fossae
from which lateral movement can be
made , at any given degree of jaw
separation(GPT-1).
4:The most posterior relation of the lower
to the upper jaw from which lateral
movement can be made at a given vertical
dimension(Boucher).

5:A maxilla to the mandible relationship in
which the condyles and the disks are
thought to be in the midmost,uppermost
position.The position has been difficult to
define anatomically but is determined
clinically by assessing when the jaw can
hinge on a fixed terminal axis (upto
25mm).It
is
clinically
determined
relationship of the mandible to the maxilla
when the condyle–disk assemblies are
positioned in their most superior position in
the mandibular fossae and against the
distal slope of the articular eminence(ash).

6:The relation of the mandible to the
maxillae when the condyles are in the
uppermost and the rearmost position in
the glenoid fossae.This position may not
be able to be recorded in the presence of
dysfunction of the masticatory system.
7: A clinically determined position of the
mandible placing both the condyles into
their anterior uppermost position.This can
be determined in patients without pain or
derangement in the TMJ (Ramfjord)

Centric relation has been described in
three
different
ways:
anatomically,
conceptually, and geometrically.
Anatomical:
It is the position of the mandible to the
maxilla, with the intra-articular disc in
place when the head of the condyle is
against the most superior part of the
distal facing incline of the glenoid
fossa.This can be paraphrased uppermost
and foremost.

Conceptual:
It is that position of the mandible relative
to the maxilla, with the articular disc in
place, when the muscles that support the
mandible are in their most relaxed and
least strained position.
Geometrical:
It is the position of the mandible relative
to the maxilla,with the intra- articular disc
in place, when the head of the condyle is
in terminal hinge axis.

Dawson’s
concept

Gelb’s
concept


Optimum functional tooth contacts
Closure in CR

Creates an unstable occlusion
Neuromuscular system
Feed back muscles
Mandibular position
More www.indiandentalacademy.com
stable occlusion

Musculoskeletal stable position
HARMONY

Stable occlusal condition


Conclusion:
Optimum occlusal conditions
during
mandibular
closure
would be provided by even and
simultaneous contact of all
posterior teeth.


Criteria for optimum functional
occlusion
Even and simultaneous contact of
all
possible
teeth when the
mandibular condyles are in their
most
superoanterior
position,
resting against the posterior slopes
of the articular eminences, with the
discs properly interposed.

Occlusal contact patterns
Direction of force
Amount of force


Criteria for optimum functional
occlusion
First - Even and simultaneous
contact of all possible teeth +
centric relation
Second – each tooth should
contact in such a manner that the
forces of closure are directed
through the long axis of the teeth.

Nutcracker theory


Canine guided occlusion


Group function occlusion


Buccal to buccal cusp contacts are
desirable
No non-working side contacts


Protrusive contacts


Postural considerations and
functional tooth contacts
Depends on head position
In the alert feeding position, as well as
in the normal upright position, the
posterior teeth should contact more
heavily
than
the
anterior
teeth
(mutually protected occlusion).

Summary
1. When the mouth closes, the condyles are
in their most superoanterior
(Musculoskeletal stable) position, resting
on the posterior slopes of the articular
eminences with the discs properly
interposed. In this position there is even
and simultaneous contact of all posterior
teeth. The anterior teeth also contact but
more lightly than the posterior teeth.

2. All tooth contacts provide axial loading
of occlusal forces.
3. When the mandible moves into a
laterotrusive
position,
there
are
adequate tooth-guided contacts on the
laterotrusive
(working)
side
to
disocclude
the
mediotrusive
(nonworking) side immediately. The
most desirable guidance is provided by
the canines (canine guidance).

4. When the mandible moves into a
protrusive position, there are adequate
tooth-guided contacts on the anterior
teeth to disocclude all posterior teeth
immediately.
5. In the alert feeding position, posterior
tooth contacts are heavier than
anterior tooth contacts.


REFERENCES
 Occlusion series in BDJ, 2001;191:6-7


Okeson
JP.
Management
of
Temporomandibular
Disorders and
Occlusion, ed. 4th, 1998; Mosby
 Ash MM and Ramfjord S. Occlusion,
ed. 4th, 1966; WB Saunders Company,
Michigan

Santos JD. Occlusion Principles and
Concepts, ed. 2nd, 1999; Ishiyaku
EuroAmerica, Inc. U.S.A.
 Shillingburg HT. Fundamentals of
Fixed
Prosthodontics,
ed.3rd,
1997;Quintessence


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