Occlusion in complete denture

Occlusal Considerations in
Complete Dentures
Dr. M Anil Goud.
Professor
Dept of Prosthodontics NRDRN Dental College Nanded

Introduction
 A literal definition of the term occlusion is the act of closure
or being closed
 But this term should have in it’s definition the concept of a
multifactorial, functional relationship between the teeth and
the other components of the masticatory system as well as
other areas of head and neck that directly or indirectly relate
to function, Para function or dysfunction of the masticatory
system
www.asiandentalacademy.orgwww.asiandentalacademy.org

Definitions
 Dorland’s dictionary(1985)-relation of
maxillary and mandibular teeth when in
functional contact during activity of mandible
 GPT 8 – 1) The act or process of closure or of
being closed or shut off
2) The static relationship between
incising or masticating surfaces of the maxillary
or mandibular teeth or tooth analogue

Difference between natural
and artificial teeth
 Proprioceptive feedback of periodontal tissues
 Pressure of occlusion on Individual tooth unit
 Malocclusion of occlusion uneventful for years
 Incising
 Bilateral balance
 Forces of mastication
5 to 175 pounds in natural teeth
9 pound in incisor area,22-24 pound in premolar &
molar area in complete denture

Requirements of complete
denture occlusion
Stability
Balanced occlusion
Functional lever balance by tooth to ridge
position
Cutting penetrating and shearing efficiency of
occlusal surfaces
Anterior incisal clearance during posterior
masticatory functions
Minimum area of occlusal contacts to reduce
the forces www.asiandentalacademy.orgwww.asiandentalacademy.org

Requirements of incising units
Sharp
No contact during mastication
Less incisal guidance considering esthetics
and phonetics
Contact only during protrusive incising
function

Requirements of the working
occlusal units
Efficient in cutting and grinding
Should have decreased Buccolingual width
Should function as group with
simultaneous harmonious contacts
Should over the ridge crest for lever
balance
Should have plane of occlusion as parallel
as possible to mean foundation area

Requirements of balancing
occlusal units
Should contact on the second molars
when the incising units contact in
function
Should contact at the end of chewing
cycle when the working units contact
Should have smooth gliding contacts for
lateral and protrusive excursions

Axioms for artificial occlusion
Sears
 Smaller area of occlusal surfaces, smaller the forces transmitted
 Vertical forces on inclined surface causes non vertical force
 Vertical forces on inclined supporting tissue causes non vertical
force
 Vertical force outside & lateral to the ridge creates tipping
forces on the bases

Occlusal schemes for
complete denture
Anatomically shaped teeth in upper and
lower dentures
Non-anatomically shaped teeth in both
dentures
A combination of both types, usually
anatomically shaped teeth in the upper

Anatomic teeth
Advantages
Efficient in cutting of food
Cuspal inclination facilitates bilateral
balance in various eccentric occlusions
Cusp teeth provides resistance to rotation in
relation to each other and to there bases
Esthetically acceptable

Disadvantages
Mandatory to use adjustable articulators
Eccentric records must be made for
articulator adjustment
The bases need prompt and frequent
refitting to keep the occlusion stable and
balanced
Cusp inclinations generate more horizontal
forces

Selection of posterior teeth
History
Anatomic teeth of 33º or more
Modified anatomic teeth between 30º and 0º
Non-anatomic or zero degree teeth

Anatomic teeth
 1913
 Gysi
 Trubyte

 1932
 Pilkington & Turner
 30 degree

Non-anatomic teeth
Advantages:
Area of freedom
Poor neuromuscular control
Horizontal forces
Simple technique and articulator

Disadvantages
Esthetically inferior
Inefficiency in mastication

 Victor & Sears
 1922-chewing members
 1927-Channel type posteriors
 Unlimited protrusive guide

 1927
 Gysi
 Crossbite
teeth

 1930
 Avery brothers
 Scissor bite technique

 1936
 McGrane
 Curved cusp posteriors

 1935
 French
 Axial occlusal forces
directed lingually

 1937
 McPleasure
 Lower bicuspid in reverse curve
 First molar flat
 Second in Monson curve

 1942
 John Vincent
 Metal inserts in resin
posteriors

1941
S. H. Payne
Lingualised
occlusion

 1961
 M. Phylip Sosin
 Crossblades of
vitalium

 1977
 Levin
 Modified Sosin’s
scheme by reducing the
size of the cross blades
to maxillary lingual
cusp for esthetics

Non-anatomic or zero degree
teeth
 1929
 Hall
 Inverted cusp tooth

 1929
 Myerson
 True cusp
 Series of transverse
buccal-lingual ridges
with sluiceways
between them

 1934
 Nelson
 Chopping block
posteriors

 1939
 Swenaon
 Non-lock

 1946
 Hardy
 Vitallium occlusal teeth

 1951
 Myerson
 Shear cusp tooth
 First cross lnnked

 1952
 Cook
 Coe Masticators
1957
Cutter bar
Upper porcelain cuspless teeth
with a metal cutting bar

1967
Frush
Linear occlusal concept

Theories of occlusion
 Theries of occlusion as related to the designs of
articulators
Bonwill’s theory of occlusion
Conical theory of occlusion
Spherical theory of occlusion
 balanced occlusion theory
Unilateral lever balance
Unilateral occlusal balance
Bilateral occlusal balance
Protrusive occlusal balance

Bonwills theory of occlusion
 1885
 Theory of equilateral
triangle
 Equilateral triangle with
10 cm (4 inch) sides
connecting both condyles
and mesioincisal angles
of the mandibular central
incisor
 Bonwil articulator

Conical theory of occlusion
 Lower teeth move
over the surface of the
upper teeth as over the
surface of a cone with
a generating angle of
45º and with a central
axis of the cone tipped
at a 15º angle to the
occlusal plane
Hall automatic
articulator by
R.E.Hall www.asiandentalacademy.orgwww.asiandentalacademy.org

Spherical theory of occlusion
 G. S. Monson (1918)
 Based on observations by
Von Spee
 Lower teeth moving over
the surface of upper teeth
as a surface of a sphere on
a diameter of 8 inches with
centre in the region of
Glabella.
 Maxillomandibular
instrument by Monson

Axioms for balance
 Wider & larger the ridge and closer the teeth to the
ridge, greater the lever balance vice versa
 Wider the ridge and the narrower the teeth greater
the balance and vice versa
 More lingual the teeth arrangement in relation to
the ridge crest, greater the balance and vice versa
 More centered the occlusal force anteroposteriorly,
greater the stability of base

Balanced occlusion theory
 Unilateral lever balance
(Equilibration of base)
 Bilateral lever balance
 Bilateral occlusal balance
 Protrusive occlusal
balance

Development of balanced
occlusion
Concept
Definition
Rationale
Goals

Concept
Von Spee (1890)- curve of Spee-
masticatory surfaces of the molars are
aligned in downward convex curve along
the upper jaw and in an upward concave
curve along the lower jaw
Alfred Gysy (1910)- condylar path follows
curved line or an S shaped curve

 B. B. McCollum (1926)-completely balanced
occlusion for natural dentition
 Clyde H. Schuyler (1929)- non-working side
contacts may be contributing factors to traumatic
injury
 Balanced occlusion good theory for complete
denture

Definition
1. Bilateral simultanious anterior and
posterior contacts of the teeth in centric
and eccentric position –(GPT 8)
2. Stable, simultaneous contact of the
opposing upper and lower teeth in centric
relation position and a continuous smooth
bilateral gliding from this position to any
eccentric positions within the normal
range of mandibular functions (Winkler)

Rationale
 Stabilization of denture
 Combination of tissue resiliency and denture
movement during function accounts for thee high
frequency of non chewing or balancing side
contacts. Denture movement regardless of
posterior occlusal form
 Shepperd(1964)- enter bolus enter balance
 Prime- enter bolus exit balance-value of smooth
gliding non-interfering bilateral tooth contact

Breumer & Hudson (1961)-complete denture do
contact at times during mastication.
Bilateral balance is even more important during
swallowing saliva, closing to reseat denture,
bruxing of teeth during stress
Do not upset the normal, static, stable and
retentive movement of denture
Ensures even pressure in all pressure in all parts
of the arch www.asiandentalacademy.orgwww.asiandentalacademy.org

Goals of balanced occlusion
Maximum simultanious bilateral contact in
centric relation
Working side contacts all along the working
side from cuspides posteriorly
Balancing in molar region in lateral position ,
one contact is sufficient
Occlusal plane parallel to the maxillary &
mandibular residual ridge

Balancing in protrusive position require
tipping of distal end of mandibular second
molar up so that mesiolingual cusp of
maxillary second molar will contact the distal
marginal ridge of mandibular second molar
Compensating curve for protrusive balance
created buy tipping the second premolar
distally, depressing the mandibular first
molar,and placing upword inclination on the
mandibular second molar www.asiandentalacademy.orgwww.asiandentalacademy.org

Laws of protrusive occlusion
 Hanau’s
study was
pioneer
explanation
 Hanau’s
laws of
articulation
and the
Hanau
Quint
1.Horizontal condylar inclination
2.Compensating curve
3.Prtrusive incisal guidance
4.Plane of orientation
5.Buccolingual inclination of tooth axis
6.Sagital condylar pathway
7.Sagital incisal guidance
8.Tooth alignment
9.Relative cusp hight

Condylar guidance
Compensating curve
Relative cusp height
Incisal guidance
Plane of orientation

Inclination of condylar
guidance
 Condylar guidance is the
guiding influence which
is furnished to the
condyles by the
temporomandibular
articulation during
essentric jaw movements
 One factor which is
present in edentulous jaw
 Can not modified by
edentulous jaw

Inclination of incisal guidance
 Guding influence which results from positional
relationships of the upper and lower anterior teeth
when the mandible ,moved into eccentric relations
to the maxillary while anterior teeth remain in
contact
 Angle in sagittal plane between incisal edges of
the upper and lower incisar teeth when closed in
centric occlusion

 Should be as flat
as esthetics and
phonetics will
permit
 Steep vertical
overlap places the
rotational centre
below the
posterior of the
mandible and
shallow above

Orientation of the occlusal
plane
Vertical location of the anteroposterior
alignment of the occlusal plane in the space
between the Camper’s line to a point, not at
the superior border, but at the centre of the
ear (Hanau)
 Camper’s plane is not only misunderstood
but also unreliable

Cephalometrically progrmmed
adjustable plane
Porion
Nasion
Anterior
nasal spine
Y= 83.4307-(0.9907-X)
Where
X= PoNANS angle value
Y= best computed value of the
occlusal plane

Inclination of the cusp
Angle between the total occlusal
surfaces of the tooth and inclination of
the cusp in relation to that surface

Swenson’s formula
Cusp inclination
=
Incisal inclination
+
fraction of distance
from incisal
guidance
Σ = v + d ( B – v )

If inclination
of the incisal
guidance is
equal to the
condylar
guidance
v = B
Then
Σ = v + B

Gysi’s formula for the second
molar
condylar guidance
inclination
M2 =
Incisal guidance
inclination
2
+
B + v
2
EM2 =

Prominence of the
compensating curve
 The anteroposterior and lateral curvature in the
alignment of the occlusal surfaces and the incisal edges
of artificial teeth which is used to develop balanced
occlusion
 It is determined by the inclination of posterior teeth and
there vertical relationship to the occlusal plane so that
the occlusal surface results in a curve that is in a
harmony with the movemnt of the mandible as guided
by the condylar path www.asiandentalacademy.orgwww.asiandentalacademy.org

Thielemann’s formula
Balance
d
occlusio
n
=
K. I.
O.P. C. OK.
K the inclination of condylar path
I the inclination of incisal guidance
C height of the cusp
OP inclination of the plane of orientation
OK prominance of the compensating curvewww.asiandentalacademy.orgwww.asiandentalacademy.org

Cusp plane and cusp plane
angle
Cusp plane- when two buccal cusps tips
and the highest situated lingual cusp cusp
tip are connected form a cusp plane
Cusp plane angle- the inclination of the
cusp plane to the plane of occlusionis called
“cusp plane angle”

Compensating curve formula
C = Σ - w
Σ Cusp angulation
w cusp plane angle

Hanau’s Quint

Trapozzano concept
Eliminated plane of orientation
Compensating curve inclination

Boucher’s concept
Three fixed factors
Compensating curve is also important
Both the cusp height and & the
compensating curve are means for solving
the problems imposed by the
Christensen’s phenomena
Occlusal plane shoud be located according
to esthetic appearance and soft tissue
anatomy

The Lott concept
Divided five factors in clear and simple chart

Levin’s concept
Eliminates the plane of orientation

Arrangement of anatomic artificial
teeth into balanced occlusion

Arrangement of nonanatomic
teeth into balanced occlusion

Centre of rotation
A line drawn at right angle to the buccal
incline of mandibular lingual cusp on the
working side and another line at right angle
to the lingual surfaces of mandibular buccal
cusp on the balancing side meet at B

Influence of incisal and condylar
guidance on the working and
balancing side
Working side inclines are not so steep as
balancing side contacts
Angle of inclination on the working side is
less in posterior area and greater towards
the incisal area
Since incisal guidance is 30 degree, a
smaller degree of angulation is seen in the
posterior region which gradually increases
towards 30 degrees the incisal area is
approached

Concepts of occlusion
Neutrocentric
Lingualized occlusion
Monoplane concept of occlusion
Lineal occlusal concept

Neutrocentric concept
De Van
Neutralization of inclines
Centralization of occlusal forces acting on
the denture foundation
Teeth should be placed where they grew as
long as mechanical laws are not violated
Factors such as orientation of occlusal
plane, compensating curve, incisal
guidance must be neutralized before
neutralization of inclineswww.asiandentalacademy.orgwww.asiandentalacademy.org

Elements of neutrocentric
concept
1.1. PositionPosition
posterior teeth over the posterior residualposterior teeth over the posterior residual
ridge as far lingually as tongue wouldridge as far lingually as tongue would
allow so that forces would beallow so that forces would be
perpendicular to the support areasperpendicular to the support areas

Proportion-
Devan reduced tooth width by 40% to
correct tooth proportion thus reduce vertical
stress on the ridge
Also horizontal and shearing stress was
reduced because friction between opposing
surfaces was decreased;such frictional
forces are resisted by the o

Pitch
Inclination or tilt
Pitch as found in
natural dentition
Parallel to the
maxillary and
mandibular bases
In natural dentition pitch of
posteriors is determined by
1.Orientation of occlusal
plane in reference to the
condylar guidance
2.The steepness of
compensating curve

Form
Flat teeth with no deflecting inclines
Reduction of destructive lateral forces

Number
 Number is reduced from 8 to 6
 Thus decreased magnitude of the occlusal force
and centralised it to second premolar & first
premolar area
 Aids in stabilityby freeing the lower molar
incline of occlusion

There should be no hesitancy in reducing
the number of teeth.
Krogman, the Anthropologist-the human
dental formula of 2-1-2-3 is evolving into
the formula 1-1-1-2

Lingualised occlusion
Occlusal scheme which uses maxillary
lingual cusps as the major functioning
occlusal element occluding with
nonanatomic or semianatomic teeth in the
lower arch
Payne- first suggested
Pound- used the term

Indications
 High priority on esthetics but the nonanatomic
occlusal scheme is indicated by oral conditions
such as sever resorption, class 2 jaw relationship
or desplaceable supporting tissue
 Complete denture opposed by a removable partial
denture

Principles
Anatomic posterior teeth in maxillary denture
Non anatomic or semianatomic in mandibular
denture
Selective grinding of mandibular posterior teeth
creates slight concavity on the occlusal surfaces
Maxillary lingual cusp contacting mandibular
teeth in working, balancing as well as protrusive
movements

Monoplane concept of
occlusion
 Sear (1949) & Devan (1984)
 Anterior teeth without vertical overlap, normal
horizontal overlap
 From 0 mm for class 3 to 12 mm for sever class 2
 Occlusal plane-
anterior point- incisal edges of canine
posterior point- a) equal division of space
b) parallel to mean foundation
c)2/3rd
way up of retromolar pad

Line from distoincisal edges of canine to
buccolingual centre of retromolar pad on
mandibular wax rim
Upper premolars and first molars arranged
in such a way that there central grooves
coincide with the line
Upper molar 2 mm above the occlusal planewww.asiandentalacademy.orgwww.asiandentalacademy.org

Lineal occlusal concept
 A straight line of points or
knife edges contacts on
artificial teeth in one arch
occluding non-anatomic
teeth in opposing arch
 Smallest lateral component
of force
 Since the area of occlusal
contacts are minimal,
frictional resistance is
reduced
 No change in location of
contacts

Locating the line of occlusal
contacts
 Stabilization of mandibular denture-
with the ridge of occlusal contacts in mandibular
arch, occlusal forses in any jaw position will be
applied to the mandibular denture at the same point
 Esthetics-
nonanatomic maxillary first premolar contoured to
the anatomically and esthetically pleasant
anatomic maxillary teeth with lingual cisps in
straight line and keeping baccal cusps out of
contacts

Combination of occlusal
forms
Non-anatomic maxillary porcelain teeth
opposing mandibular porcelain teeth
 least wear, hence in young healthy patient
with adequate interridge distance
 earlier occlusal disharmonies as porcelain
does not wear fast enough to keep up with
changes of the residual ridge

 Non-anatomic maxillary plastic teeth opposing
mandibular plastic lineal teeth
 Susceptibility to wear
 Lineal becomes flat plane type
 Contraindicated in young patients and patients with
bruxism and abrasive diet
 Advantageous in patientas with resorbed ridges and
poor muscle function and who need treatment dentures
for rapidly deterioring ridges www.asiandentalacademy.orgwww.asiandentalacademy.org

Nonanatomic maxillary plastic teeth
opposing mandiblar porcelain lineal teeth
More self adjusting as mouth changes occur
Necessity to reshape maxillary posterior
teeth

Anatomic maxillary porcelain teeth
opposing non-anatomic mandibular
plastic teeth
Esthetics
Line of contact between lingual cusps of
maxillary porcelain teeth and non-anatomic
mandibular posterior teeth

 Tooth positioning for lineal occlusion
 Anterior teeth with no vertical overlap
interferance
 Posteriorly as high as practical to aid in
developing protrusive balancing contacts with flat
plane of occlusion
 Lower teeth set first and centered over the crest of
the ridge
 Flat surfaces of maxillary posterior teeth parellel
to cross arch horizontal plane www.asiandentalacademy.orgwww.asiandentalacademy.org

Discussion
 Various contravercies in various concepts, theories and
philosophies
 Occlusion is a part of stomatognathic system and not
just setting of teeth
 occlusion in complete denture if based on unsound
principles, actually worsens the physical, mental and
social condition of old patients rather than improving it
 There is nothing called ideal occlusion before the great
variable Human factor

Summary and conclusion
 Nature of supporting structures for complete
denture and forces directed to them by creates a
special type of problem
 Biologic, physiologic and mechanical principles
need to be considered and carefully coordinated in
this new man made occlusion
 First concern is for the health and preservation of
the supporting structures.
 Apply all factors that favor the stability of base and
design the occlusion to function optimally in
relation to the forces of mastication.

Occlusion in complete denture

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Occlusion in complete denture