Occlusion 26 /certified fixed orthodontic courses by Indian dental academy

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CONTENTS
1)
2)

3)
4)
5)

Introduction
Definition
Review of Literature
Concepts of Occlusion
Development of Occlusion
(a) Mouth of Neonate
Gum Pad Stage
Precociously erupted primary teeth
(b) Deciduous Dentition
Eruption age and sequence of deciduous dentition
Characteristics of Primary Dentition
Spacing
Normal Overbite & Deep Bite
Inter Incisal Angle
Occlusal Relations
(c) Mixed Dentition Period
First Transitional Period
Inter Trasitional Period
Second Transitional Period.
(d) Self Correcting Dental Anomalies

6) Permanent Dentition
(a)

Alignment and Occlusion of Dentition
Dental Arch Form
(b) Intra Arch Alginment
Curvatures of Occlusal Plane
(c) Inter Arch Alignment
Arch Length
Arch Width
Bucco-occlusal contact relationship
Mesio Occlusal Contact Relationship (in posteriors)
Class-I
Class-II
Class-III
Common Occlusal Relationship of Anterior Teeth
(d) Andrew’s Six Keys to Occlusion
(e) Various Mandibular Movements & Occlusal Contacts during these
movements.

7) Types of Occlusion
8) Bio-Mechanics of Occlusion
9) Applied Aspects
10) Occlusion in Prosthodontics
11) Conclusions
12) References.

INTRODUCTION
 Occlusion --> Ob + Claudre
" To Close Up"
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The term "occlusion' used in dentistry means contact
relationship of teeth in function or parafunction.
 However, term refers not only to contact of arches at an
occlusal interface but also to all those factors concerned
with development and stability of masticatory system and
with use of teeth in oral motor behaviour. The primary
components of human dental occlusion are :
(a) The dentition
(b) Neuro Muscular System
(c) Cranio facial structures.
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The development and maturation of these
components are inter-related, so that growth,
adaptations and change actively participate in
development of adult occlusion.

DEFINITION

 According to GPT/8 : Occlusion may be defined as :
- act or process of closure or being closed or shut off.
- static relationship between incisal and masticatory surfaces of
maxillary or mandibular teeth / tooth analogues.
 In latin Occ = Up
Clusion Closing

 JABLONSKI (1982)
It is relationship between all components of masticatory system in normal
function, parafunction and dysfunction including morphology, and functional
features of contacting surfaces of opposing teeth and restorations, occlusal
trauma, neuromuscular physiology, psychophysiological state and the
diagnosis, prevention and treatment of functional disorders.

 DYNAMIC OCCLUSION (Davies and Gray)
Refers to the occlusal contacts that are made whilst mandible is moving
relative to the maxilla, the mandible being guided by muscles of mastication
and anterior and posterior guidance mechanism of mandible, Anterior
guidance of teeth which may touch during eccentric movement of mandible,
posterior guidance, TMJ.


 As defined by Dorland's Medical Dictionary
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Occlusion is Act of closure or state of being closed.
According to "WHEELERS occlusion refers not only to contact of
arches at an occlusal interface but also to all those factors
concerned with development and stability of masticatory system and
with use of teeth in oral motor behaviour.
According to Bishara, Occlusion is way maxillary and mandibular
teeth articulates.
Ash and Ramfjord defines occlusion as contact relationship of
teeth in function and parafunction.
In reality, Dental Occlusion is much more complex relationship
because it involves study of :
Teeth
:
Morphology
:
angulation
Muscles of Mastication
Skeletal Structures
TMJ
Functional Jaw Movements.


Review of Literature
 Peter E. Dawson in an article quoted a classification
system for a occlusions that relate maximal
intercuspation to the position and condition of
temporomandibular joints.
 A recently introduced term ‘adaptive centric posture’ is
used in this classification to distinguish deform TMJs that
have remodeled or adapted to a conformation that can
comfortably accept maximal loading.


 Classification of Occlusion:

 Type I Maximal intercuspation occurs in harmony with the verifiable centric
relation
 Type I (A) Maximal intercuspation occurs in harmony with adaptive centric
posture.
 Type II Condyles must displace from verified centric relation for maximal
intercuspation to occur.
 Type II (A) Condyles must displace from adaptive centric posture for
maximal intercuspation to occur

 Type III Centric relation or adaptive centric posture can not be verified. The
TMJs accepts loading without causing discomfort, so the relationship of
maximal intercuspation to correct condyle position can not be immediately
determined.The condition is diagnosed as transitory and treatable to
achieve centric relation or adaptive centric posture

 Type IV occlusal relationship is in a stage of progressive disorder because
of pathologically unstable and actively progressive deformity of TMJs.

Type IV occlusion may be described specifically as (1) progressive open

.

occlusion (2) Progressive asymmetry (3) progressive mandibular retrusion


CONCEPTS OF OCCLUSION
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GNATHOLOGICAL APPROACH
PHILOSOPHY OF ARNE G. LAURITZEN
NILES GUICHET AND GNATHOLOGY
VISION OF TRANSOGRAPHIC CONCEPT
FREEDOM IN CENTRIC CONCEPT
OCCLUSAL CONCEPTS OF SCHUYLER
BEYRON’S OCCLUSAL CONCEPTS
THE PANKEY – MANN PHILOSOPHY
DAWSON’S CONCEPT OF COMPLETE DENTISTRY
GERBER’S CONDYLAR DISPLACEMENT THEORY


 DEVELOPMENT OF OCCLUSION
MOUTH OF NEONATE
(1)
Gum Pads :
Alveolar processes at birth are called Gum Pads
There are horse shoe shaped
Consist of 2 parts : labiobuccal and lingual.
The 2 portions of gum pads are separated from arch other by
groove called Dental Groove. The gum pads are divided into 10
segments by certain grooves called Transverse Grooves. Each of
these segments consist of one developing deciduous tooth sac.
Gingival Groove Separates gum pad from palate and floor of mouth.
Transverse groove between canine of first deciduous molar segment
is called lateral sulcus. The lateral sulcii are useful in judging interarch relationship in early stage. The lateral sulcus of mandibular
arch is normally more distal to that of maxillary arch.


 Upper and lower gum pads are almost similar to each other. Upper

gum pad is both wide as well as longer than mandibular gum pad.
Thus when upper and lower pads are approximated there is complete
overjet all around. Contact occurs between upper and lower gum
pads in first molar region and space exists between them in anterior
region. This infantile open bite is considered normal & helps in
suckling


DECIDUOUS DENTITION
Any considerations of development of occlusion should begin with
occlusion of Deciduous teeth.
(a) Eruption Age and Sequence of Deciduous Dentition :
Mandibular central Incisors are 1st teeth to erupt by 6-7 months of age
Variation of 3 months from mean age has been accepted as normal
Sequence of eruption is : A - B - D - C - E.
(b) Characteristics of Primary Dentition
(1) Spacing
(i) Physiologic Spacing
Normal spaces between deciduous teeth
Help to accommodate larger permanent successors
Baume in 1950 termed it as :
Closed arch dentition
Spaced arch dentition


(ii) Primate Space (Anthropoid / Simian
Space)
The spacing found mesial to maxillary
cuspids and distal to mandibular
cuspids are termed as Primate spaces.
(iii)Delabarre in 1918 was the first to
describe inter proximal spacing in
primary dentition.
(2) Normal Overbite and Deepbite
Normal overbite is usually present in
children.
In some cases, deep bite is present during
initial stages of development.
Later deepbite is reduced due to :
- Eruption of deciduous molars.
- Attrition of Incisors
- Forward movement of mandible due to
growth.

(3) Overbite and Overjet
During Primary dentition
- Overbite decreases by slight amount.
- Overjet reduced to zero.
From the early mixed dentition to completion of permanent occlusion.
average overbite increases slightly and then decreases.
(4) Inter Incisal Angle :
It is angle formed between the intersection of long axis of upper
incisors and lower incisors.
In Primary dentition, as incisor are more upright, there is an increase in
Inter incisal angle.
(5) Occlusal Relations
Baumes Classification
(a) Flush terminal plane - 76%
(b) Mesial Step Terminal Plane - 14%
(c) Distal Step Terminal Plane - 10%


Flush terminal

Distal step

Mesial step


Mixed Dentition Period
- Begins at approximately 6 years of age.
- Classified into 3 phases :
(a)
First Transitional Period :
Characterized by :
(i) Emergence of 1st permanent molars.
• Mandibular 1st molar - 1st permanent tooth to erupt at 6
years of age.
• Location and relationship depends upon
distal surface relationship upper and lower
2nd deciduous molars.


BAUMES CLASSIFICATION
Flush Terminal Plane :

• 76 %Distal surface of upper and lower 2nd deciduous molars are in
one vertical plane. Thus erupting 1st permanent molars may be in
a flush or end on relationship. This is normal feature of deciduous
dentition. For transition of such an end on molar relation to class - I
molar relation, the lower molar has to move forward by about 3-5mm
relative to upper molar. This occurs by utilization of Physiologic
spaces and leaving space in lower arch and by differential forward
growth of mandible.
• Shift of lower molar from flush terminal plane to class - I
relation can occur in 2 ways : (i) Early (ii) Late Shift
 Early shift occurs during early mixed dentition period. Eruptive
force of 1st permanent molar is sufficient to push deciduous first
and 2nd molars forward in arch to close primate space and
thereby establish class I molar relationship.
 Many children lack primate space and thus erupting permanent
molars are unable to move forward to establish Class I
relationship. In these cases, to when deciduous 2nd molar
exfoliate the permanent first molar drift mesially utilization
leeway space. This occur in late mixed dentition period and is
thus called late shift.

Mesial Step Terminal Plane (14%) :
In this type of relationship distal surface of lower 2nd deciduous
molar is more mesial than that of upper. This permanent molars
erupt directly in
Angles Class - I occlusion. This type of mesial step terminal
plane most commonly occur due to early forward growth of
mandible. If differential growth of mandible in forward direction
persists, it can lead to Angles Class-III malocclusion

Distal Step Terminal Plane (10%)
This is characterized by distal surface of lower
2nd deciduous surface of lower 2nd deciduous
molar being more distal to that of upper. Thus
erupting molars may be in Angle's class II
malocclusion.


(ii) Exchange of Incisors
- Permanent Incisors are larger in size than primary.
- Warren Mayne gave Incisal liability in 1969.
This is difference between amount of space needed for
accommodation of incisors and amount of space
available for this :
- In maxilla - 7mm.
In mandible - 5mm.
- Incisor liability is overcome by following factors.
 Utilization of Inter dental spaces seen in primary
dentition.
 Increase in Inter canine width.
 Change in Incisor Inclination.
 Incisor Position.

b) Inter Transitional Period
This phase during mixed dentition period is relatively
static and no change occurs.
(c)Second Transitional Period
- Characterized by replacement of deciduous molars and
canines by permanent premolars and canine
respectively
- Leeway Space of Nance - The combined mesiodistal
width of permanent canines and premolars is usually
less that that of deciduous canines and molars.
In Maxilla 1.8mm
In Mandible 3.4mm.
This excess space available after exchange of deciduous
molars and canines is utilized for mesial drifts of
mandibular molars to establish class I molar relation.

SELF CORRECTING DENTAL ANOMALIES
These anomalies occur in certain period of development and get corrected
by themselves as development progresses. These are also called
Transient or self correcting malocclusion
I. During Gum Pad Stage
- Increased overjet all around
- Reterognathic relation of lower gum pad.
- Anterior open bite.
- Infantile swallow.
II. During Deciduous
- Spacing
Physiologic spaces
Primate spaces
- Anterior deep bite
- Molar Relationship.
III. During Mixed Dentition
- End on molar relationship.
- Incisal Liability


Ugly - Duckling Stage - Also known as "Broad Bent Phenomenon".

Seen at around 10 - 13 years of age.
In this there is unesthetic metamorphosis leading to Esthetic Results.
This is particular situation seen during eruption of permanent canines. As
developing permanent canines erupt, they displace roots of lateral incisor
mesially. This result in transmitting of force on to roots of central incisors
which gets displaced mesially. A resultant divergence of crowns of 2 central
incisors cause midline spacing. The condition usually corrects by itself
when canines erupt and pressure is transferred from roots to coronal area of
incisors.


PERMANENT DENTITION
 Permanent dentition forms within jaws soon after birth,
except for cusps of 1st permanent molars which form
before birth. Permanent incisors develop lingual or
palatal to deciduous incisors and move labially as they
erupt. Premolars develop below diverging roots of
deciduous molars. Eruption sequence of permanent
dentition may exhibit variation. Frequently seen
sequence in maxillary arch are :
6 - 1 - 2 - 4 - 3 - 5 - 7. or
6 - 1 - 2 - 3 - 4 - 5 - 7.
In mandibular arch
6 - 1 -2 - 3 - 4 - 5 - 7
or
6 – 1- 2 - 4 - 3 - 5 - 7.

Alignment and Occlusion of Dentition :
Dental Arch Form
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The teeth are positioned on maxilla and mandible in such a

way as to produce curved arch when seen from occlusal surface.
The arch form is in large part determined by shape of underlying
basal bone.
•
On basis of qualitative observations, antheropologists have
described general shape of palatal arch as being paraploid, Ushaped, ellipsoid, round and horse shoe shape
•
Discrepancies in arch between the maxillary and mandibular
arches generally result in poor occlusal relationships.

INTRA ARCH ALIGNMENT
Intra arch tooth alignment refers to relationship of teeth to each other
within dental arch.
The occlusal planes of dental arches are curved in manner that
permits maximum use of tooth contact during function as flat
occlusal plane will not permit simultaneous functional contact in
more than one area of dental arch.


 The occlusal surfaces of teeth are made up of numerous cusps,

grooves and sulci. During function these occlusal elements permit
effective breaking up of food and mixing with saliva to form bolus
that is easily swallowed.
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The area of tooth between, buccal and lingual cusp tips of
posterior teeth is called occlusal table . The major forces of
mastication are applied on this area. The occlusal table represents
approximately 50% - 60% of total buccolingual dimension of
posterior tooth and is postitioned over long axis of root structure. It
is called inner aspect of tooth because it falls between cusps tips.
Likewise, occlusal area outside cusp tips is called outer aspect.
The inner and outer aspects of tooth are made up of inclines that
extend from cusp tips to either the central fossa.
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Contour on lingual and labial surfaces of teeth. Thus these
inclines are called inner and outer inclines.


 CURVATURES OF OCCLUSAL PLANE
Curve of Spee
When examining the arches from lateral view, mesiodistal axial relationship
can be seen. If lines are extended through long axis of roots occlusally
through crowns, angulation of teeth with respect of alveolar bone can be
observed. In mandibular arch both anterior and posterior teeth are mesially
inclined. The second and third molars are more inclined premolars. In
maxillary arch a different pattern of inclination erupts. The anterior teeth are
generally mesially inclined, with most posterior molars being distally inclined.
If from lateral view an imaginary line is draw through buccal cusp tips of
posterior teeth. Curved line following plane of occlusion will be established
that is convex in maxillary arch and concave in mandibular arch. The convex
and concave lines match perfectly when dental arches are placed into
occlusion. This curvature of dental arches was first described by Von Spee &
is therefore referred to as Curve of Spee


Curve of Wilson :
When observing dental arches from frontal view, buccolingual axial
relationship can be seen. Generally posterior teeth in maxillary arch
have slight buccal inclination. In mandibular arch posterior teeth
have
slightly lingual inclination. If a line is drawn through buccal and
lingual cusp tips of both right and left posterior teeth, curved plane of
occlusion will be observed. The curvature is convex in maxillary arch
and concave in mandibular arch. Again, if arches are brought into
occlusion, tooth curvatures will match perfectly. This curvature in
occlusal plane observed from frontal view is called CURVE OF
WILSON


Curve of Monsoon
Bonwill, one of first to describe dental arches, noted that an
equilateral triangle existed between centres of condyles and
mesial contact areas of mandibular central incisors. He
depicted this as having 4-inch sides. In other words, the
distance from mesial contact area of mandibular central
incisor to centre of either condyle was 4 inches and
distance between centres of condyles was 4 inch. In 1932,
Monson, used Bonwill's triangle and proposed a theory that
sphere erusted with radius of 4 inches, with centre that was
an equal distance from occlusal surfaces of posterior teeth
and from centres of condyles. The curve formed was
known as CURVE OF MONSON


INTER ARCH TOOTH ALIGNMENT
Refers to relationship of teeth in one arch to those in other. When two
arches come in contact, as in mandibular closure,occlusal relationship of
teeth is established.

Arch Length :The distance of line that begins at distal surface of third molar
extends mesially through all proximal contact areas around entire arch and
end at distal surface of opposite third molar.
For maxillary arch length is 128mm. For mandibular arch arch length is
126mm.

Arch Width : is distance across the arch. The width of mandibular arch is
slightly less than maxillary arch., thus when the arches occlude, each
maxillary tooth is more facially positioned than occluding mandibular tooth.
Because maxillary teeth are more facially positioned, normal occlusal
relation is :
 Buccal cusps of posterior mandibular teeth occlude along central fossa area
of maxillary teeth.
 Lingual cusps of posterior maxillary teeth occlude along central fossa of
mandibular teeth.

CENTRIC / SUPPORTING AND NON CENTRIC /
GUIDING CUSPS.

 Buccal cusp of mandibular posterior teeth and lingual cusp of maxillary

posterior teeth occlude with opposing central fossa. These cusps are
called CENTRIC OR SUPPORTING CUSPS
 These cusps are mainly important for keeping distance between maxilla
and mandible. This distance supports the vertical facial height and is
called VERTICAL DIMENSION OF OCCLUSION.
 Buccal cusps of maxillary posterior teeth and lingual cusp of mandibular
posterior teeth area called GUIDING OR NON CENTRIC CUSP /
SHEARING CUSP
 The major role of non-centric cusp is to minimize tissue impingment and
maintain bolus of food on occlusal table for mastication. They also give
stability to mandible so that when teeth are in full occlusion tight definite
occlusal relationship results. This relationship of teeth in their maximum
intercuspation is called Maximum Inter Cuspal Position.


BUCCOLINGUAL OCCLUSAL - CONTACT RELATIONSHIP
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If imaginary line is extended through all buccal cusp tips of mandibular
posterior teeth, bucco occlusal line is established. In normal arch this line
flows smoothly and continuously, revealing general arch form. It also
represents demarcation between inner and outer aspects of buccal cusps.
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If imaginary line is extended through lingual cusps of maxillary
posterior teeth, linguo occlusal line is observed. This line reveals general
arch form and represents demarcation between outer and inner aspects of
centric cusps.
 If third imaginary line is extended through central develop mental grooves
of maxillary and mandibular posterior teeth, the CF line is established.


 Once CF is established important relationship of proximal contain areas is
noted. These areas are generally located slightly buccal to CF line which
allows greater lingual embrasure area and smalled buccal embrasure
area. During function, larger lingual embrasure area will act as major
spillway for food bang masticated when teeth as brought in contact,
majority of food is shunted to tongue, which is more efficient in returning
food to occlusal table the is buccinator and perioral musculature.
 To visualize buccolingual relationship of posterior teeth in occlusion
appropriate imaginary lines must be matched. The BO line of mandibular
occludes with CF line of maxillary teeth. Simultaneously the CO maxillary
teeth occludes with CF line of mandibular teeth.


MESIODISTAL OCCLUSAL - CONTACT RELATIONSHIP
Occlusal contacts occur when centric cusp contact opposing C.F. Viewed from
facial, these cusps typically contact in one of 2 areas.
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CF areas
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Marginal ridge and embrasure areas.
Contacts between cusp tips and CF area have been involved to grinding of
pestle in mortar. When 2 unlike curved surfaces meet, only certain portions
come into contact at given time, leaving other areas free of contact to act as
spillways for substance being crushed. When mandible shifts during
mastication, different areas contact, creating different spillways. This shifting
increases efficiency of mastication. The second type of occlusal contact is
between cusp types and marginal ridges. Marginal ridges are slightly raised
convex areas at mesial & distal borders of occlusal surfaces that joins with inter
proximal surface of teeth. The most elevated portion of marginal ridge is only
slightly convex. Therefore his type of contact is best depicted by cusp tip
contacting flat surface. In this relationship the cusp tip can penetrate through
food easily and spillways are provided in all directions. When mandible moves
laterally, actual contacts areas shifts, increase efficiency of cheweing stroke.
Exact cusp tip is not solely responsible for occlusal contact. Circular area
around true cusp tip with radius about 0.5mm provides contact area with
opposing tooth surface.


OCCLUSAL RELATIONSHIPS OF
POSTERIOR TEETH
Class-I
(i) Mesiobuccal cusp of mandibular first molar

occludes in embrasure area between maxillary
2nd premolar and 1st molar.
(ii) Mesiobuccal cusp of maxillary first molar is
aligned directly over buccal groove of
mandibular 1st molar.
(iii) Mesiolingual cusp of maxillary first molar is
situated in CF area of mandibular 1st molar.
In this relationship each mandibular tooth
occludes to its counterpart and adjacent
mesial tooth.
Contacts between molar occur on both cusp
tips and fossae and on cusp tips and marginal
ridges.
Two variation in occlusal contact patterns can
result with respect to marginal ridge areas. In
some instances cusps contacts the embrasure
area directly, resulting in 2 contacts on area of
cusp tips. In other instance, cusp tip is
positioned so that it contacts only one
marginal ridge, resulting in only one contact on
cusp tip.


Class II

(i)
(ii)
(Iii)

In some patient maxillary arch is
large or advanced anteriorly or
mandibular arch is small or
positioned posteriorly. These
conditions will result in
mandibular 1st molar being
positioned distal to class I molar
relationship. Described as Class
II molar relationship.
Mesiobuccal cusp of mandibular
1st molar occludes in CF area of
maxillary 1st molar.
Mesiobuccal cusp of mandibular
first molar is aligned with buccal
groace of maxillary 1st molar.
Distolingual cusp of maxillary
first molar occludes in CF area
of mandibular 1st molar.

Class-III
Due to predominant growth of
mandible. In this relationship,
growth positions mandibular molar
mesial to maxillary molars.
(i) Distobuccal cusp of mandibular 1st
molar is situated in embrasure
between maxillary 2nd premolar and
1st molar .
(ii) Mesiobuccal cusp of maxillary 1st
molar is situated over embrasure
between mandibular 1st and 2nd
molar.
(iii) Mesolingual cusp of maxillary 1st
molar is situated in mesial pit of
mandibular 2nd molar

OCCLUSAL RELATIONSHIP OF ANTERIOR TEETH

 Maxillary anterior teeth are normally positioned labial to mandibular anterior
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teeth.
Both maxillary and mandibular anteriors are inclined to the labial, ranging
12-28º from vertical reference line.
Incisal edges of mandibular incisors contacting lingual surfaces of maxillary
incisors. These contacts commonly occur in lingual fossae of maxillary
incisors approximately 4mm gingival to incisal edges.
Purpose of anterior teeth is to guide mandible during various lateral
movements. The anterior tooth contacts that provide guidance of mandible
are called Anterior Guidance, Characteristics of anterior guidance are
dictated by exact position and relationship of anterior teeth, which can be
examined both horizontally and vertically.
Horizontal distance by which maxillary anteriors overlap mandibular
anteriors is called Horizontal over lap - Overjet. It is the distance between
labial nasal edge of maxillary incisor and labial surface of mandibular incisor
in ICP.
Vertical overlap is distance between incisal edges of opposing anterior teeth
which is approximately 3 - 5mm.
Important function of anterior teeth is that of performing initial acts of
mastication. Anterior teeth function to incise food when introduced in oral
cavity.
Anterior teeth also plays significant role in speech, lip support and
aesthetics.

ANDREW’S SIX KEYS TO NORMAL OCCLUSION
Andrew’s during 1970s put forward six keys to normal occlusion.
The six key are considered under the following headings:

MOLAR INTERARCH RELATIONSHIP.
The Mesio buccal cusp of upper first molar should occlude in the groove
between mesial and medial buccal cusp of lower first molar. The mesio
lingual cusp of upper first molar should occlude in the central fossa of
lower first molar. The crown of upper first molar must be angulated so that
distal marginal ridge occludes with the mesial marginal ridge of second
molar
MESIO DISTAL CROWN ANGULATION
 The Second Key makes use of a line that passes along the long axis of
crown through the most prominent part in the center of labial or buccal
surface. This line is called long axis of clinical crown.
 For occlusion to be considered normal, gingival part of long axis of crown
must be distal to the occlusal part of the line. Different teeth exhibit
different crown angulation.


LABIO LINGUAL CROWN INCLINATION
 The crown inclination is determined from mesial or distal view. If the gingival
area of crown is more lingualy placed than the occlusal area, it is referred to
as positive crown inclinication. In case the gingival area of crown is more
labially or buccally placed than the occlusal area it is referred to as negative
crown inclinication
 The Maxillary incisors exhibit a positive crown inclination while mandibular
incisors show negative crown inclination. The maxillary and mandibular
posteriors have negative crown inclination.
ABSENCE OF ROTATION.
Normal occlusion is characterized by absence of rotation.
Rotated posteriors occupy more space in a dental arch. While rotated incisors
occupy less space in dental arch.
TIGHT CONTACTS
For normal occlusion there should be tight contact between adjacent teeth.
CURVE OF SPEE
Normal occlusal plane according to Andrew’s should be flat with curve of spee
not exceeding 1.5 mm.


 VARIOUS MANDIBULAR MOVEMENTS AND
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OCCLUSAL CONTACTS DURING THESE
MOVEMENTS
To this point only static relationships of posterior and
anterior teeth have been discussed. Masticatory system
is extremely dynamic. TMJ and associated musculature
permit mandible to move in all 3 planes i.e. sagittal,
horizontal, frontal. Along with these movements come
potential tooth contacts. The term Eccentric have been
used to describe any movement of mandible from ICP
that result in tooth contact. Three basic eccentric
movements are :
(i) Protrusive
(ii) Laterotrusive
(iii) Retrusive

 (i)

Protrusive Mandibular
Movement : This movement
occurs when mandible moves
forward from ICP. Any area of
tooth that contacts opposing tooth
during protrusive movement is
considered to be protrusive
contact. In normal occlusal
relationship the predominant
protrusive contacts occur on
anterior teeth, between incisal and
labial edges of mandibular incisors
and against lingual fossa areas
and incisal edges of maxillary
incisors. On posterior teeth
protrusive movement causes
mandibular centric cusps to pass
anteriorly across occlusal surfaces
of maxillary teeth. Protrusive
posterior contacts occur between
distal inclines of maxillary lingual
cusps and mesial induces of
opposing fossae and marginal
ridges. Posterior protrusive
contacts can also occur between
mesial inclines of mandibular
buccal cusps and distal inclines of
opposing fossae and marginal
ridges

 (ii) Laterotrusive Mandibular Movement

During lateral mandibular movement; right and left mandibular

posterior teeth move across their opposing teeth in different
directions. If for example, mandible moves laterally to left, left
mandibular posterior teeth will move laterally across their opposing
teeth. However, right mandibular posteriors will move medially
across their opposing teeth.

Posterior teeth on left side during left lateral movement reveals
that contacts can occur on 2 incline areas. One contact between
inner inclines of maxillary buccal cusps and outer inclines of
mandibular buccal cusps. Other contact is between outer inclines of
maxillary lingual cusps & inner inclines of mandibular linqual cups.
Both these contacts are called LATEROTRUSIVE

The term lingual to lingual Laterotrusive & buccal to buccal
laterotrusive issued to differentiate those occuring between
opposing lingual cusp from those occurring between buccal cusps.


 Working Contact :- Is

commonly used for both these
laterotrusive contacts

During same lateral
movement, right mandibular
posterior teeth are passing in
medial direction across their
opposing teeth. The potential
sites for occlusal contacts are
between inner inclines of
mandibular buccal cusps. These
are called Mediotrusive
contacts. During left lateral
movement most function occur
on left side, therefore right side
has been desiqnated as nonworking side . Thus these
mediotrusive contacts are also
called Nonworking contacts or
Balancing contacts.

 (viii) Retrusive Mandibular

Movement.:- Occurs when
mandible moves posteriorly
from 1CP.These movements
are restricted by ligamentous
structures. During retrusive
movement mandibular buccal
cusps move distally across
occlusal surface of their
opposing maxillary teeth.
Areas of potential contact
occurs between distal inclines
of mandibular buccal cusps &
mesial inclines of opposing
fossae & marginal ridges. In
maxillary arch retrusive
contacts occurs between
mesial inclines of opposing
CF's & marginal ridges.

TYPES OF OCCLUSION

 Normal Occlusion: Within frameworks of function occlusion (the correlation

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

between occlusion of teeth and movement of mandible) any mouth that has
exhibited its ability to survive is considered normal. It is :
Physiological
Adaptive
Physiological Occlusion: is state of equilibrium in which there is no
pathology or other dysfunction of any component of somatognathic system
occurring as result of occlusal activity, regardless of arrangement of teeth.
Pathological Occlusion: It occurs when anything related to occlusal activity
causes injury or impaired function somatognathic system.
Adaptive Occlusion: It is between physiologic and pathologic occlusion.
Structurally there is potential dysfunction, but it has not occurred to any great
extent, e.g. persons having facets of wear has adaptive and require periodic
examination but not treatment.
Ideal Occlusion: A so called ideal occlusion can also be called, physiologic,
functional or normal. When local occlusion exists. Somatognathic system
usually functions in good health. In an ideal occlusion lateral forces are
eliminated or minimized and occlusal forces are directed along long tooth and
distributed equally on as many teeth as possible. Stamp cusps occlude against
marginal ridges or into opposing occlusal fossa rather than interproximal
embrasure. Usually there is full component of teeth in both arches. Each
posterior tooth should have at least one antagonist to occlude & work against.

 The most ideal occlusion is mutually Protected

occlusion in which posterior teeth protect anterior
teeth during centric closure & anterior teeth protect
posterior teeth in any movement or position away from
centric contact position.
 Disclusion: During protrusive sliding movements of
mandible the incisors and canines act together in
coupling effect as anteriors discludes in group
function. In lateral excursions of mandible cuspids on
working side act as discluders. Some times central
and lateral incisors also help cuspids which is not
always present but acceptable.

When determinants of occlusion and tooth
arrangements are compatible, an occlusion can be
considered stable. Stuart refers to tooth arrangement
as an ORGANIZED OR ORGANIC OCCLUSION .

THERAPEUTIC OCCLUSION
It is one in which arrangement of teeth and their opposing occlusal surfaces
satisfies function and esthetic requirements while distributing the forces of
occlusion over as many teeth during functions of mandible.
Three most popular concepts of therapeutic occlusion are:
(a) Fully balanced occlusion.
(b) Unilateral balanced occlusion
(c) Cusp-fossa occlusion
(a) Fully Balanced Occlusion : It originated in denture construction, where it was
felt that there should be bilateral equal contact of anterior and posterior teeth
during CR as well as during protrusive and lateral excursive movement of
mandible. The concept was advanced by Gpsi, McCollum. Gerber et al. It
works for removable dentures but in natural dentition it doesn't offer 'position' for
teeth or mandible that are god holding positions during centric closure.
(b) Unilateral Balanced Occlusion : Advanced by Schuyler, Pankey, Mann &
Ramfjord. It allows for contact of all teeth during centric position. With some
freedom of movement anteroposteriorly. The centric slide of about 0.2 - 1mm at
same vertical dimension is known as long centric. During lateral movement,
disclusion occurs against canines and buccal cusps of maxillary and mandibular
premolars and molars of working side. This is referred to as Group Function.
There are no tooth contacts on non working during lateral excursive movement.
Group function or posterior teeth with equally distributed occlusal forces on each
involved tooth is very difficult to achieve but even if done, patient often develops
occlusal awareness that leads to bruxism and occlusal disharmony.

(c) Cusp- Fossa occlusion :- Concept is based on gnathological
principles of jaw function as well as physiological principles of
somatognathic system.

During closure of posterior teeth into the intercuspation
position, all stamp cusps occlude simultaneously into their opposing
occlusion fossa. It is a distal limit occlusion in that the condyles &
consequently cusp of mandibular teeth are functioning in their most
distal positions.

At same time that stamp cusps make final contact in cusp
fossa occlusion, condyles are positioned in their most retruded or
unstrained position in their respective fossae. Since CO & CR tooth
contacts are coincident there is not centric interference to cause
occlusal slide & deviation of mandible. Patient close to CR occlusion
where no single tooth carries more or less than its share of occlusal
load. Occlusal forces are at an equilibrium throughout the mouth.
During centric contact of posterior teeth in cusp-fossa occlusion
anterior teeth do not touch having ideal space of .01mm betweem
maxiallary & mandibular incisors & canines at CO. In this occlusion
centric closure is positive closing position in which all posterior teeth
contact simultanceously. The reciprocating contacts positioned as
they are around fossa prevent tipping or rotation or teeth when
occlusal forces are applied.

Mutually protected occlusion : When condyler & incisal guidance act together to disclude the

posterior teeth. It is referred to as mutually protected occlusion. A
cusp-fossa arrangement is functional occlusion. It is an artificial
occlusion in which attention is directed specially to performance as
differently from structure & appearance. eg. in cusp-fossa occlusal
scheme a tooth is not always restored to its textbook image. It may
have slightly altered shape to allow proper position of cusp- ridges &
groves in function.
 Anterior teeth protect the posterior & posterior teeth protect anterior
during denture closure. Cusp-fossa occlusion can therefore be
defined as mutually protected occlusion.
 During working side movement cannot act as discluders of posterior
teeth hence called canine protected occlusion, canine rise, canine
disclusion & canine left.
 This scheme is designed to eliminate lateral forces on posterior
teeth. Because anterior teeth are lightly in contact in CO, posterior
teeth support forces in CO protecting, periodontally vunerable
anterior teeth from heavy clenching & chewing forces. Canine is
structurally, neurologically & positionally well suited to support
lateral forces in exclusion. So this type of occlusion also called
Canine Guided Occusion.

BIO-MECHANICS OF OCCLUSION:
Dental factors of occlusion.
If dentition is functioning in health and form of dentition is esthetic,
restoration of individual teeth requires duplication of existing
occlusal form.
Unless there is evidence of dysfunction such as occlusal trauma,
excessive tooth wear, clearly unacceptable occlusal plane
orientation or joint and muscle dysfunctioning occlusion should be
considered normal restorations should be patterned to follow
morphology of adjacent and opposing teeth. Anatomic factors
important in the development occlusal patterns for restored tooth
include the following :
 Cusp Height
 Cusp angle
 Marginal ridge height
 Contact area position
 Contact area height
 Fossa size
 Triangular and oblique ridge height.
 Triangular and oblique ridge directions
 Groove depth and width
 Groove direction
 Faciolingual dimension of occlusal table

 Changes that should be particularly avoided include irregular adjacent







marginal ridge heights, changes in size and location of proximal
contact area, widening or narrowing the buccolingual width of occlusal
table, increase or decrese of cusp angulation, groove depth or
angulation and location of occlusal contact areas. Common problems
observed from such changes include the following
Wedging of food interproximally during mastication that is often
associated with irregular marginal ridge heights and missing contact
areas
Deflection of mandible from intercuspal position that is often
associated with abnormally steep cusp heights or pre-mature occlusal
contacts.
Working cusp interferences that are often associated with abnormally
steep cusp heights or improperly angled triangular or oblique ridges
and grooves.
Balancing cusp interferences associated with abnormally steep cusp
heights
Supra eruption and shifts in tooth position that must result from lack of
occlusal and proximal contacts.


APPLIED ASPECTS
1.

2.
3.
4.
5.
6.

The concepts of occlusion are established & recognized as guidline by all
departments of dentistry. The need to maintain this relation is of almost
importance. The salient features are :In small children with decidous dentition of nursing bottle caries or rampant
caries is present then teeth get decalcified at very rapid rate & if unrestored
for some time the other teeth migrate mesally the contact relation as well as
integrity & occlusion of arch is lost.
In children if we see that by age of 5-6 years the physiologic space have not
yet develop that it is indicative of developing malocclusion.
In cases of restoration of teeth using amalgam / composite /GIC/ Zinc
phosphate etc. we should take care to check for high points, because these
can lead to deviations in occlusion & discomfort to patient.
Extraction of deciduous teeth unless & until its the last or only alternative,
should not be done. This may lead to malocclusion because these decidous
teeth act as guide for permanent teeth.
If in mixed dentition period we see developing situation of crowding for
permanent teeth then serial extraction should be considered.
When giving patient fixed or removable prosthesis complete / partial than
the points occlusion should be kept in mind & implemented during
construction phase patient needing CD must not be given non-anatomic
teeth or set up should not monoplane, just for ease of clinician.
Multiple extractions without replacement should not be done as it may cause
changes in vertical dimension of occlusion & may also lead to mutilated or
collapsed occlusion.

OCCLUSION IN PROSTHODONTICS:
Occlusion may be discussed from two view points
Static Relations
Dynamic Relations

STATIC CONCEPT:
Static relations in occlusion are those which occur in
many possible contacts of teeth without interposition of
food.Static Relations in occlusion include
 Centric occlusion
 Protrusive Occlusion
 Right & left lateral occlusion
 Intermediate occlusion

DYNAMIC CONCEPT:
It is primarily concerned with opening & closing
movements involved in mastication while static concept
is concerned primarily with tooth contacts made at
various positions. In this concept, jaw movements &
tooth contacts that are made as teeth of one jaw guide
over teeth of opposing jaw are not functional movements
or contacts. This phase of occlusion is admitted to be
controlled by TMJ, muscles & ligaments & teeth.
Functional movements are the movements of lower teeth
as they approach upper teeth in chewing cycle.The
direction of closure is influenced by
 TMJ
 Occlusal form of teeth
 Occlusal plane
 Musculature (contraction & relaxation times of muscle)
 Resistance of food & relative tolerance of supporting
tissues.

TYPES OF COMPLETE DENTURE OCCLUSION:
Balanced Occlusion
Monoplane Occlusion
Lingualized Occlusion
I) BALANCED OCLUSION:
DEFINITION: Simultaneous contacting of maxillary & mandibular
teeth on right & left and in posterior & anterior occlusal areas in
centric & accentric positions, developed to lessen or limit tipping or
rotating of denture bases in relation to supporting structures.
CHARACTERISTICS REQUIREMENTS OF BALANCED
OCCLUSION:
 All teeth of working side should glide evenly against opposing teeth.
 No single tooth should produce any interference or disocclusion of other
teeth.
 There should be contacts in balancing side, but they should not interfere
with smooth gliding movements of working side.
 There should be simultaneous contact during protrusion.


IMPORTANCE OF BALANCED OCCLUSION:
 Balanced occlusion is one of most important factors that affect

denture stability. Absence of occlusal balance will result in leverage
of denture during mandibular movement.
 Sheppard stated that, “ENTER BOLUS, EXIT BALANCE” according
to this statement, balancing contact is absent when food enters oral
cavity. This makes us think that balanced occlusion has no function
during mastication or as its role essential in complete denture.
 Brewer reported importance of balanced occlusion. He reported
that on an average normal individual makes masticatory tooth
contact only for 10 mnts in one full day as compared to 4 hours of
total tooth contact during other functions. So for these hours of
tooth contact, balanced occlusion is important to maintain stability of
denture. Hence, balanced occlusion is more critical during
parafunctional movements.


GENERAL CONSIDERATIONS FOR BALANCED
OCCLUSION:
Ideal balanced occlusion can be achieved in cases with wide & large ridges
& in complete dentures, with teeth arranged dose to ridge.
Complete dentures that have teeth arranged away from the ridge & those
that rest on wide ridges provide ideal balanced occlusion.
Ideal balance can be achieved by arranging the teeth slightly on lingual
side of crest of ridge. Arranging the teeth buccally will lead to poor
balanced occlusion. If the teeth are set outside ridge the denture may
elevate on one side during tooth contact stability of denture against
these lever forces is called as LEVER BALANCE .Lever balance is
different from balanced occlusion. It can be safely quoted that lever
balance is also necessary for balanced occlusion.
Complete denture should be designed in such a way that the forces of
occlusion are centered anteroposteriorly in the denture.
TYPES OF BALANCED OCCLUSION:
 Unilateral balanced occlusion
 Bilateral balanced
 Protrusive balanced occlusion
 Lateral balanced occlusion

i)

UNILATERAL BALANCED OCCLUSION:
This is type of occlusion seen on occlusal surface of teeth on one side when they
occlude simultaneously with smooth, uninterrupted glide. This not followed
during complete denture construction. It is more pertained to fixed partial
dentures.

ii)

BILATERAL BALANCED OCCLUSION:
This is type of occlusion that is seen when simultaneous contact occurs on both
sides in centric & eccentric positions bilateral balanced occlusion helps to
distribute the occlusal load evenly across the arch & therefore helps to improve
stability of denture during centric eccentric or parafunctional movements.
For minimal occlusal balance, there should be at least 3 points of contact on
occlusal plane. More the number of contacts, better the balance Bilateral
balanced occlusion can be protrusive or lateral balance.

iii)

PROTRUSIVE BALANCED OCCLUSION:
This type of balanced occlusion is present when mandible in forward direction &
occlusal contacts are smooth & simultaneous anteriorly & posteriorly. There
should be at least three points of contact in occlusal plane. Two of these should
be located posteriorly & one should be located in anterior region. This is absent
in natural dentition.

FACTORS THAT GOVERN PROTRUSIVE BALANCE:
 Inclination of condylar path: This inclination recorded on patient represents the






path travelled by condyle in protrusion which is modified by combined action of
all tissue in temperomandibular joint & ridges covered by recording bases.
Angle of incisal guidance closes for patient.
Angle of plane occlusion
Compensating curves chosen www.indiandentalacademy.com condylar path
for orientation with
Cuspal height & inclination of posterior teeth.

iv) LATERAL BALANCED
OCCLUSION:

In lateral balance, there will be
a minimal simultaneous three point
contact present during lateral
movement of mandible.

Lateral balanced occlusion is
absent in normal dentition, when a
dentulous person with canine guided
of all occlusion moves his mandible
to right, there will be canine guided
disocclusion of all these teeth. Even
canine of opposite side will not have
contact.

If this relationship is followed
during teeth arrangement then
denture will lose its stability due to
lever action. To prevent this teeth
should be arranged such that there
is simultaneous teeth contact in
balancing & working sides.


FACTORS THAT GOVERN LATERAL BALANCE:
 Angle of inclination of condylar path on balancing side.
 Angle of indication of plane of occlusion on balancing side and working
side.
 Compensating curve on balancing side and working side.
 Buccal cusp heights or indication of teeth on balancing side.
 Lingual cusp heights or indication on working side.
 Bennett side shift on working side.
 Steep cusps, produce more displacement of denture base that shallower
or cuspless forms. Forces of occlusion acting on complete denture should
be balanced from right to left and anterior to posterior direction.
 An increase in any of above forces will affect balanced occlusion leading
to compromised stability of denture.
 If vertical overlap of anterior teeth is increased for aesthetic and phonetic
reasons, then the horizontal overlap should adjusted to reduce the incisal
guidance angle.
 This adjustment provides space for free movement of ant-teeth. Without
this adjustment there will be increased anterior interference leading to
initial instability of denture base during protrusion. In long run, this may
lead to resorption of residual alveolar ridge in anterior region.

FACTOR INFUENCING BALANCED
OCCLUSION
Five basis factors that determine the balance of an occlusion
are :
Inclination of condylar path or condylar guidance
Incisal guidance
Orientation of plane of occlusion or occlusal plane
Cuspal Angulation
Compensating Curve


(i)

Inclination of Condylar Path :

 It is also called first factor of occlusion. This is only factor, which can

be recorded from patient. It is registered using protrusive
registration (i.e. patient is asked to protrude with occlusal rims. Interocclusal record material is Injected between occlusal rims in this
position. The occlusal rims with inter occlusal record are transferred
to articular. Since the occlusal rims are in protrusive relation, upper
member of articulator is moved back to accommodate them. The
interocclusal record is carefully removed and upper member is
allowed to slide forward to its original position. The condylar
guidance should be adjusted till upper member slides freely into
position. It is transferred to articulator as condylar guidance.

Increase in condylar guidance will increase jar separation
during protrusion. This factor of balanced occlusion can't be
modified. All other four factors of occlusion should be modified to
compensate effects of this factor. In patients with steep condylar
guidance, incisal guidance should be decreased to reduce amount
of jaw separation produced during protrusion and vice-versa. But it
should be remembered that incisal guidance can't be made steep
because it has its own effects

(ii)

Incisal Guidance :

 This is defined as "The influence of contacting surfaces of mandibular and

maxillary anterior teeth on mandibular movements".

It is called 2nd factor of occlusion. It is determined by dentist and
customized for patient during anterior try in. It acts as controlling path for
movement of casts in an articulator. It should be set depending upon the
desired overjet and overbite planned for the patient. If overjet is increased,
the inclination of incisal guidance is decreased. If overbite is increased, then
incisal inclination increases. The incisal guidance has more influence on
posterior teeth than the condylar guidance. This is because the action of
incisal inclination is closer to teeth than action of condylar guidance. During
protrusive movements, incisal edge of mandibular anterior teeth move in
downward and forward path corresponding to palatal surfaces of upper
incisors. This is known as protrusive incisal path or incisal guidance. The
angle formed by this protrusive path to horizontal plane is called as
Protrusive Incisal path inclination or incisal guide angle.

Influences of shape of posterior teeth. If incisal guidance is steep,
steep cusps or steep occlusal plane or steep compensatory curve is needed
to produce balanced occlusion. In comple denture, the incisal guide angle
should be as flat as possible. Hence, while arranging anterior teeth, for
aesthetics, a suitable vertical overlap and horizontal overlap should be
chosen to achieve balanced occlusion. Also, incisal guidance can't be
altered beyond limits. The location and angulation of incisors are governed
by various factors like aesthetics, function and phonetics etc.

(iii) Plane of Occlusion or occlusal plane :




It is defined as an imaginary surface which is related anatomically to cranium
and which theoretically touches incisal edges of incisors and tips of occluding
surface of posterior teeth. It is not plane in true sense of word but represents
mean curvature of surface.
It is established interiorly by height of lower canine, which nearly coincides
with commissar of mouth and posteriorly by height of retromolar pad. It is
usually parallel to traqus line or camper's line. It can be slightly altered and its
role is not as important as other factors. Tilting the plane of occlusion beyond
10° is not advisable.

(iv) Compensating Curve :






It is defined as "the anteroposterior and lateral curvature in alignment of
posterior and lateral curvature in alignment of occluding surfaces and incisal
edges of artificial teeth which are used to develop balanced occlusion."
It is important factor for establishing balanced occlusion. It is determine by
inclination of posterior teeth and their vertical relationship to occlusal plane.
The posterior teeth should be arranged such that their occlusal surfaces from
a curve. This curve should be in harmony with movements of mandible
guided posteriorly by condylar path.
A steep condylar path requires sleep compensatory curve to produce
balanced occlusion. If shallow compensating curve is given for same
situation, there will be loss of balancing molar contacts during protrusion.
There are 2 types of compensating curves namely :
Anteroposterior curves
Lateral Curves

 ANTEROPOSTERIOR COMPENSATING CURVES : These are
compensatory curves running in anteroposterior direction. They
compensate for curve of spee seen in natural dentition.

 Compensating Curve for Curve of Spee : Defined as Anatomic Curvature
of occlusal alignment of teeth beginning at tip of lower canine and following
buccal cusps of lower canine and following buccal cusps of natural
premolars and molars,continuing to anterior border of ramus as described by
Grafton. It is an imaginanory curve joining buccal cusps of mandibular
posterior teeth starting from canine passing through head of condyle. It is
seen in natural dentition and should be reproduced in a C.D. The
significance of this curve is that, when patient moves his mandible forward,
posterior teeth set on this curve will continue to remain in contact. If teeth
are not arranged according to this curve, there will be dis-occlusion during
protrusion of mandible (Christensens Phenonenon).

 LATERAL COMPENSATING CURVES : These curves run transversely
from one side of arch to other the following curves fall in this category.
 Compensating Curve for Monson Curve : Monson’s curve is defined as
'The curve of occlusion in which each cusp and incisal edge touches or
conforms to segment of a sphere of 8 inches in daimeter with its centre in
region of Glabella."

This curve runs across palatal and buccal cusps of maxillary molars.
During lateral movements of mandibular lingual cusps on working side
should slide along inner inclines of maxillary buccal cusp. In balances
side the mandibular buccal cusps should contact inner inclines of
maxillary palatal cusp. Thiswww.indiandentalacademy.com
relationship forms a balance. Only if teeth
are set following the monsoons curve there will be lateral balance of
occlusion.

 Compensating Curve for Anti-Monson or Wilsons Curve :

Wilsons curve is defined as " A curve of occlusion which is convex
upwards".
This curve run and opposite to direction of monsoons curve this
curve is followed when 1st premolars are arranged. The premolars
are arranged according to this curve so that they do not produce
any interferance to lateral movements.
 Reverse Curve : "A curve of occlusion which is transverse cross
section conforms to line which is convex upward." It was originally
developed to improve stability of denture. It is explained in relation
of mandibular posterior teeth. The reverse curve was modified by
Max Pleasure to for pleasure curve.
 Pleasure Curve : "A curve of occlusion which is transverse crosssection conforms to line which is convex upward except for last
molars.
It was proposed by Max Pleasure. He proposed this curve to
balances occlusion and increase stability of denture. Here the first
molar is horizontal and 2nd premolar is bucally tilted. The 2nd molar
independently follows the anteroposterior compensating curved and
lingually tilted. This curve runs from palatal cusp of 1st premolar to
distobuccal cusp of 2nd molar. The 2nd molar gives occlusal
balance and 2nd premolar gives lever balance.

(V) CUSPAL ANGULATION :







Cusp angle is defined as " The angle made by average slope
of cusp with cusp plane measured mesiodstally or
buccolingually."
Cusps on teeth or inclination of cuspless teeth are important
factors that modify effect of plane of occlusion of
compensating curves. The mesiodistal cusps lock occlusion
such that repositioning of teeth doesnot occur due to settling
of base.
In order to prevent locking occlusion, mesiodistal cusps are
reduced during occlusal reshaping. In absence of mesiodistal
cusps, buccolingual cusps are considered factor for balanced
occlusion. In cases with shallow overbite, cuspal angle should
be reduced to balance incisal guidance. This is done because
jaw separation will be less in cases with overbite. Teeth with
sleep cusp will produce occlusal interference in these cases.
In case with deep bite, jaw separation is more during
protrusion teeth with high cuspal inclines are reguided in
these cases to produce posterior contact during protrusion.


MONOPLANE OR NON-BALANCED OCCLUSION
It is an arrangement of teeth with form or purpose. It includes the
following concepts of occlusion:
 Spherical theory
 Organic occlusion
 Occlusal balancing ramps for protrusive balance
 Transographics
General Considerations
The following point have to be considered while using a non-balanced
occlusion for a denture:
 Opposing artificial teeth should not contact when the jaws are in
eccentric relation, because it may give destabilizing forces to the
basal seat area. The architecture of the basal seat does not allow
tooth contact when the mandibule is in eccentric position.
 Tooth contact should occur only when the mandible is in centric
relation to the maxilla.
 The patient should be encouraged to repeat the mandibular
movements till there is no discomfort in the centric relation.


LINGUALIZED OCCLUSION:

 Lingualized occlusion, one of the more popular occlusal schemes was

introduced by Alfred Gysi in 1927. The basic concepts of lingualized
occlusion were suggested by Payne. It was Earl pound who first used the
term “lingualized occlusion”.

This occlusal scheme was introduced as an attempt to maintain the
esthetics and food penetration advantages of the anatomic form while
maintaining the mechanical freedon of the non-anatomic forms.

Indications

 In a situation where the patient places a high priority on aesthetics but the

oral condition requires the use of non-anatomic teeth, e.g. severe alveolar
ridge resorption, Class II ridge relationship.
 When a complete denture opposes a removable partial denture.
 Parafunctional habits.

Advantages
Payne stated the advantages as:
 Can be adapted to different types of ridges
 A solid maximum intercuspation
 Absence of deflective occlusal contact in lateral excursions
 Esthetic arrangement of teeth
 Balanced articulation can be achieved.

Types of Tooth Forms used
 Semianatomic teeth
 Non-anatomic teeth
 Myerson lingualized integration tooth molds.
Principles of Lingualized Occlusion
 Anatomic teeth are used for the maxillary denture. Teeth with
prominent lingual cusps are helpful.
 The buccal cusps are raised above the occlusal plane. They have
no functional role. They improve esthetics and help prevent cheek
biting.
 Non-anatomic or semi-anatomic teeth are used for the mandibular
denture. A narrow occlusal table is preferred where severe residual
ridge resorption has occurred.
 Modification of the mandibular posterior teeth is accomplished using
selective grinding.
 When the patient moves into a working relationship, the lingual cusp
of the maxillary teeth functions against the mandibular teeth (hence
the term lingualized occlusion.)


CONCLUSION :


To understand occlusion in broadest sense, it is necessary to consider, in
addition to TMJ articulation, muscles and teeth, some of neurobehavioral
mechanism that gives meaning to presence and function of masticatory
system. Although many of neural interactive mechanisms between occlusion
& thoughts, sensibleness and emotions are complex and often intermediate,
it is possible to suggest strategies that could account for variety of
responses that occur in function and parafunction.
 The obvious strategy to compensate for wear of proximal contact areas is
mesial migration of teeth, and strategy to compensate of for wear of
occlusal surfaces is explain of teeth. The strategy for regulating the
contraction of jaw elevators to achieve normal resting position of mandible
with a small interocclusal space is postural refresh. The overall strategy for
motivation to have access to muscle of mastication might be to provide
'drive' for ingestive processes, specially during early stages of devlopment
of masticatory system and maturation of nervous system. Swallowing in fetal
life, suckling in newborn and chewing in young infant.
 Functional disturbances of masticatory system may involve psycho
physiological mechanisms that are related to tech and their functions.
Therefore occlusal interferences to function or parafunction may then
involve more than simply contact relations of teeth they may involve psycho
physiological mechanisms of human behavior as well.

REFERENCES

 The Glossary of Prosthodontic Terms 8th Ed. Prostho-dent 2005; 94

: 7-92.
 Stanley Jablonski. Jablonskis Dictionary of Dentistry. Ist Ed; 2005.
A.I.T.B. S. Publishers and Distributors: 556
 Mayor M. Ash, Stanley J. Nelson. Wheeler’s Dental Anatomy
Physiology and Occlusion, 8th Ed. Saunders 2003: 437-488.
 Peter E. Dawson; Classification system for occlusion that relates
maximal intercuspation to position and condition of
tempromandibular joints. J. Prosthel Dent 1996; 75(1) : 60-6.
 Mac Donald J.W.C. Relatioship between occlusal contacts and jaw
closing muscle activity during tooth clenching. J Prosthet Dent 1984:
52(5): 718-29.
 Graf H., Dent M., Zander. HA. Tooth contact patterns in mastication.
J Prosthet Dent 1963 ;
:1055-66
 Santos J.S. Occlusion Principles and concepts, 2nd Ed. A.I.T.Bs
Publishers and Distributers : 117-33.
 Balaji S.I. Orthodontia the Art and Science 2nd Ed. Arya publishing
house : 45-58.



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


Moyers RE. Handbook of orthodontics 4th Ed. Year book Medical
publishers : 126-140.
Tand S. Textbook of Pedodontics 1st Ed. Paras Publishing House
:117-19
Okeson J.P. Management of Tempromandibular Disorders and
Occlusion, 8th Ed. Saunders 2003: 437-88.
Parker M.W. The significance of occlusion in restorative dentistry.
Dental clinics of North America 1993; 37(3) : 341-51.
Warner S. Biomechanics of Occlusion and articulators. Dental
Clinics of North America 1995; 39:257-84.
Boucher C.O. Occlusion in Prosthodontics. J. Prosthel Dent J 95:
3(5) : 633-56.
Nallaswamy D. Text book of Prothodontics. 1st Ed. Jaypee
Brothers Medical publishers : 181-198.
George B. Textbook of complete Denture Prosthodontics. Ist Ed.
CBS Publishers and Distributors: 232-32.


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