COMPLETE DENTURE

OCCLUSION
IMPORTANT TERMINOLOGIES
Occlusion in CD
the static relationship
between the incising or
masticating surfaces of the
maxillary and mandibular
teeth, or tooth analogs

Articulation
the contact relationship
between the occlusal
surfaces of teeth during
function
IMPORTANT
TERMINOLOGIES
Centric occlusion
Eccentric occlusion
an occlusion other than centric occlusion
Protrusive occlusion
Lateral occlusion
IMPORTANT TERMINOLOGIES
Working side
The side toward which the mandible moves in
a lateral excursion
Non working (balancing) side
That side of the mandible that moves toward
the median line in a lateral excursion.
OCCLUSAL SCHEMES FOR
CD
Balanced
articulation

monoplane
articulation

Lingualized
articulation
BALANCED OCCLUSION/ARTICULATION

1️⃣ 2️⃣
Bilateral There should
simultaneous be no
contact betw. interferences
anterior & during
posterior movement
teeth during from centric
all centric position to
and eccentric eccentric
positions positions
3️⃣
The movements
should be in
harmony with TMJ &
neuromuscular
control
REQUIREMENTS FOR CD
OCCLUSION:
Stability of the denture in both centric and
eccentric relations.
Balanced occlusal contacts (tripod contact) during all
eccentric movements.
Unlocking the cusps mesiodistally so the denture can
settle.
The cuspal height should be reduced to control the
horizontal forces.
Incisal clearance during all posterior functions.
MECHANICS OF BALANCED
OCCLUSION
Christensen’s
phenomenon
In natural teeth or in
unbalanced occlusion, when
the mandible moves in
protrusive direction, the
condyles move down the
slope of the glenoid fossae,
causing the whole mandible to
move downwards and the
posterior teeth to separate.
This is separation, called
Christensen’s phenomenon.
 The occlusal schemes provided for complete
dentures differ significantly from those found in
most natural dentitions.

The dentate occlusion is often canine guided or

demonstrates group function. In each case the teeth
contact on the working side but usually disclude on
the non-working side in lateral excursions.
Similarly, the posterior teeth disclude in protrusive
excursions (Christensen’s phenomenon).
In natural teeth or in unbalanced occlusion,
when the mandible moves in protrusive
direction, the condyles move down the slope of
the glenoid fossae, causing the whole mandible
to move downwards and the posterior teeth to
separate.
This is separation, called Christensen’s
phenomenon. When mandible is protruded,
only the incisal edges of upper and lower
anterior teeth contact.

Such an occlusion in complete

denture could cause tipping and
instability of the denture in posterior
section.
 Dentures are different; the occlusion is
designed to provide stability.

Therefore the non-working side teeth also

contact in lateral excursions to prevent the
denture from tipping, giving rise to the term
‘balancing side’.

The posterior teeth also contact in

protrusive excursions.
It can be a challenge to achieve such an
occlusal scheme.

The contacts must be harmonized in inter-

cuspal position (ICP), lateral excursions and
in the protrusive movement.

To add to this challenge, the occlusal scheme

must first be established on a device that
mimics the patient’s mandibular movements
before being confirmed intraorally. It follows
that the articulator on which the occlusal
scheme is established should reproduce the
movements of the mandible precisely, and
allow for movements that may occur during
mastication.
BALANCED OCCLUSION
Balanced occlusion refers to the occlusal
scheme that is provided for dentures and features:
• inter-cuspal position (ICP) = retruded contact
position (RCP);
• ICP on posterior teeth;
• working side and balancing side contacts in lateral
excursions;
• anterior and posterior contact in protrusive
excursions. .
BALANCED
OCCLUSION
Inter-cuspal position = retruded
contact position
The ICP contacts are established on the artificial
teeth to coincide with the RCP position recorded
at the registration stage.

Having ICP and RCP coincident allows thewearer

to function from centric relation, which is
considered the optimal position for function and
comfort. .
 Inter-cuspal position on
posterior teeth
The ICP contacts are established between the palatal
cusp of the upper teeth and the central fossae of
the lower teeth, as shown in Figure 106.

The buccal cusp of the lower also contacts the

central fossae of the upper teeth (Figure 107).

ICP contacts may occur on anterior teeth where

the skeletal classification permits (i.e. class III),
which may be complicated by a crossbite (Figure 108) .
Working side and balancing
side contacts in lateral
excursions
During excursions, the upper palatal cusps
of the working side teeth maintain contact
with the buccal facing slope of the lower
lingual cusps as shown in Figure 109.

The lower buccal cusp maintains contact

with the palatal facing slope of the upper
buccal cusp as shown in Figure 110.
On the balancing side, the upper palatal
cusp maintains contact with the lingual
facing slope of the buccal cusp as shown in
Figure 111. The greater the number of
balanced contacts during these
excursions, the greater the stability of
the denture. .
Anterior and posterior contact in
protrusive excursionsDuring
protrusive excursions, the anterior teeth
contact and simultaneous contact should
be provided between the posterior teeth to
prevent the dentures from dislodging
(Figure 112).
All of the contacts in excursions are
produced to harmonize with the mandibular
movement, which itself is determined by
the movement of the condylar head as it
travels down the articular eminence. .
 To
improve
To stability
decrease &
soreness retention
&
resorptio
n of
residual To
ridge improve
oral
comfort
of the
patient

Advantages of Balanced
Occlusion
 How Could WE
Achieve Balanced
Occlusion In CD?
FACTORS AFFECTING BALANCED
OCCLUSION (HANAU’S QUINT) *
1. Condylar Guidance
2. Incisal Guidance
3. Plane of occlusion
4. Cuspal inclination
5. Compensating curve.
 FACTORS AFFECTING
BALANCED OCCLUSION
CONDYLAR
GUIDANCE*
Mandibular guidance
generated by the condyle
and articular disc traversing
the contour of the glenoid
fossae

The posterior determinant of

mandibular movement
CONDYLAR
GUIDANCE ANGLE
The angle formed by an
imaginary horizontal line at the
superior head of the condyle
and the path that the condyle
will pass through during
function

Varies from individual to

individual because of
anatomical differences
INCISAL GUIDANCE *

It’s the influence of the

contacting surfaces of the
mandibular & maxillary anterior
teeth on mandibular movement
INCISAL GUIDANCE
ANGLE
The angle formed by the intersection of
the plane of occlusion and a line within
the sagittal plane determined by the
incisal edges of the maxillary and
mandibular central incisors when the
teeth are in maximum intercuspation
INCISAL GUIDANCE ANGLE

This angle varies directly with the vertical

overbite and inversely with the horizontal
overjet
This angle is set to 10˚ in CD and not
exceeding 20˚
INCISAL GUIDANCE

↓ Incisal Guidance Angle by ↑ horizontal

overlap
INCISAL GUIDANCE

For CD, the incisal guidance should be as

shallow as esthetics and phonetics will
permit when arrangement of anterior teeth
to reduce protrusive displacing forces
INCISAL GUIDANCE
↓ Incisal Guidance Angle
by either:*

↑ horizontal overlap
↓ vertical overlap
IF INCREASED INCISAL
GUIDANCE ANGLE FOR CD?
During protrusion:

Upper denture drops at the back

Lower denture slides backward

PLANE OF OCCLUSION

Its inclination can be altered

slightly *

It is not as important as other

factors
CUSP HEIGHT &
ANGULATION

It is the smooth gliding

of the cusp tips along
the cusp inclines of the
opposing teeth to
provide balanced
articulation
CUSP HEIGHT &
ANGULATION
Anatomic teeth are easier to
balance than nonanatomic teeth

Cuspal inclines should not be too

steep as it can increase lateral
forces

It is possible to decrease cuspal

height by using compensating
curves
COMPENSATING CURVES

Artificial curves introduced into

complete denture occlusion to achieve
balanced occlusion

Are among the most important

determinants of occlusal balance
COMPENSATING CURVES

The anteroposterior curving (in the

median plane) and the mediolateral
curving (in the frontal plane) within the
alignment of the occluding surfaces and
incisal edges of artificial teeth that is
used to develop balanced occlusion
COMPENSATING CURVES
is one of the important factors in
establishing a balanced occlusion so that
the occlusal surface results in a curve that
is in harmony with the mandibular path as
guided posteriorly by the condylar
guidance and anteriorly by the incisal
guidance.

For a steep CG, a steep CC is necessary for

balanced occlusion. A lesser CC for the
same CG results in separation of posterior
teeth.
THE CURVATURES IN NATURAL
DENTITION
Curve of Spee
An arc of a circle 65mm
to 70mm radius that
touches the tips of all
the mandibular teeth
when the skull is
viewed laterally; when
continued it touches
the anterior surface of
the condyles
Significance: In protrusion the posterior teeth
arranged incorporating this curve will remain in
contact without disocclusion.
TEROPOSTERIOR CURVATURE
MEDIOLATERAL CURVATURE
This curve runs across the palatal and buccal cusps
of the maxillary molars. During lateral movement
the mandibular buccal cusps on the working side
should slide along the inner inclines of the maxillary
buccal cusp. On the balancing side the mandibular
buccal cusps should contact the inner inclines of the
maxillary palatal cusp. This relationship forms a
(lateral balance.)
It is determined by the inclination of the posterior
teeth and their vertical relationship to the occlusal
plane so that the occlusal surface results in a
curvature that is in harmony with the movement of
the mandible as guided posteriorly by the condylar
path.
MEDIOLATERAL CURVATURE

This curve runs across the palatal and

buccal cusps of the maxillary molars.

During lateral movements:

1. Working side: lower buccal cusps slide
against ……..
2. Balancing side: lower buccal cusps slide
against ……
MEDIOLATERAL CURVATURE
COMPENSATING CURVES
Anteroposterior curve
*

Mediolateral curve ¤
COMPENSATING CURVES

The steepness of the curve necessary to

achieve balance is the result of guiding
influence of angle of condylar guidance
and angle of incisal guidance

It is functionally and mechanically

advantageous to keep compensating
curve as modest as possible → This is
accomplished by setting as shallow an
incisal guidance as phonetics, esthetics
permit
THEILMANN’S
FORMULA

IGxCG = CHxOPxCC
CCORDING TO THE FORMULA
To achieve balanced occlusion: For high condylar
guidance we need to have high compensating
curve, occlusal plane and cuspal height.

To achieve balanced occlusion: For high incisal

guidance we need to have high compensating
curve, occlusal plane and cuspal height.
To achieve balanced occlusion, the steeper the
condylar guidance, the greater the cusp height
toward the posterior or the steeper the
compensating curves

To achieve balanced occlusion, the steeper the

compensating curves, the less the cusp height
toward the posterior
OCCLUSAL SCHEMES
FOR CD
PHILOSOPHIES OF DENTURE
OCCLUSION
Many philosophies of arranging denture occlusion
No definitive scientific studies prove one occlusal
scheme clearly superior
OCCLUSAL SCHEMES
FOR CD

. Balanced articulation
. monoplane articulation
. Lingualized articulation
Lingualized
Occlusion
Max. lingual
cusps contact
central
fossae/marginal
ridge
~ 1mm space
between buccal
cusps
INGUALIZED OCCLUSION
Lingualized occlusion
is a type of bilaterally
balanced occlusal
schemes *
Anatomic teeth are
used in the maxilla
opposing a flat-
cusped, or shallow
cusped mandibular
tooth.
 LINGUALIZED
OCCLUSION
Forces directed toward lingual side
Maxillary lingual cusps articulate
with the mandibular central fossae
Elimination of contacts on the
buccal cusps in both centric and
eccentric
The aim is to provide greater
masticating efficiency and the
elimination of lateral interferences
LINGUALIZED
OCCLUSION
Lingualized (lingual
contact)
Maxillary anatomic (33°)
Mandibular Teeth
Steep Condylar Guidance
Shallow cusped
(Anatoline)
Shallow Condylar Guidance
Non-anatomic (Portrait
0°)
Lingualized
Occlusion

Verify centric
No max. buccal cusp
contacts in:
• Centric
• Lateral excursions
CONTRAINDICATIONS OF BALANCED
OCCLUSION & LINGUALIZED OCCLUSION
Extreme cases of the following:

Difficulty in obtaining repeatable centric

record (incoordination, jaw malrelations)

Severe ridge resorption (lateral forces displace

the denture) may more easily be handled
with a monoplane scheme
MONOPLANE ARTICULATION
(NEUTROCENTRIC CONCEPT)

o Cuspless teeth (0°) on a

flat plane with 1.5-2.0 mm
overjet
o No cusp to fossa
relationship
o No anterior contacts in
centric position
MONOPLANE
ARTICULATION
Eliminate cusps
lateral forces reduced
improves stability
Simplifies tooth
arrangement
MONOPLANE
ARTICULATION

No overbite (would
cause tilting)
Overjet of 2 mm is
used to create an
illusion of overbite
MONOPLANE
ARTICULATION

Excursions - may or may

not contact on balancing
sides
Depends on condylar
inclination and other
aspects of the tooth
arrangement
MONOPLANE
ARTICULATION

Anterior teeth make

contact in excursions
Modifications have
been proposed to
minimize the tilting
potential:
Compensating curves
MONOPLANE OCCLUSION
WITHOUT CONDYLAR INFLUENCE
MONOPLANE OCCLUSION
MONOPLANE
ARTICULATION
Advantages
Technically easier to achieve
Use when:
Difficulty obtaining repeatable
centric records (muscle
incoordination)
Skeletal malocclusion (Class II, III)
Severe residual ridge resorption
Reduces horizontal forces
MONOPLANE
ARTICULATION

Disadvantages

Poorer appearance
Can be unstable if condylar guidance is
steep (posterior teeth separate, leaving
only the anteriors in contact)
MONOPLANE ARTICULATION

Contraindications:
The patient has high expectations for
improved appearance
Very steep condylar guidance may
make a monoplane scheme less stable,
unless modifying ramps or
compensating curves are used.
When 1.5-2.0mm of overjet can be set, a
lingualized occlusion (left) can have
overbite set. Monplane occlusion (right)
should normally have no overbite set.