The document discusses various concepts related to complete denture occlusion including: - The history of dental occlusion in mammals and its development. - Andrews' six keys to normal occlusion which are seen in natural dentition. - Differences between natural tooth occlusion and artificial denture occlusion. - Various occlusal schemes for complete dentures including balanced, lingualized, and monoplane occlusion. - Requirements for incisive, working, and balancing units in occlusal schemes.

1. BY:- DR PRANAV VERMA
PG 1ST YEAR

2. • INTRODUCTION
• CONCEPTS OF COMPLETE DENTURE OCCLUSSION
• BALANCED OCCLUSSION
• LINGUALIZED OCCLUSSION
• MONOPLANE OCCLUSSION
• DISCUSSION OF TEETH ARRANGEMENT UNDER
VARIOUS OCCLUSSAL SCHEMES
• SUMMARY
• REFERENCES

3. INTRODUCTION
• DEFINITIONS OF OCCLUSION
• HISTORY
• DEVELOPMENT OF DENTAL OCCLUSION
• BIOMECHANICS OF OCLLUSION
• DIFFERENCES BETWEEN NATURAL AND
ARTIFICIAL OCCLUSION
• REVIEW OF LITERATURE

4. INTRODUCTION
OCCLUDE MEANS TO “CLOSE”
“The static relationship between the incising or masticating
surfaces of the maxillary or mandibular teeth or tooth
analogues” GPT 8
“The act or process of closure or of
being closed or shut off.”
“Any contact between the incising or masticating surfaces of the maxillary
and mandibular teeth.”
Occlusion is an important factor which governs the retention and stability of
the complete denture in vivo.

5. TERMINOLOGIES:-
CENTRIC OCCLUSION:- The occlusion of opposing
teeth when the mandible is in centric relation. This may or may
not coincide with the maximal intercuspal position gpt 8
ECCENTRIC OCCLUSION:- an occlusion other than centric occlusion
gpt8
MAXIMUM INTERCUSPATION:- complete intercuspation of opposing
teeth independent of condylar positions gpt8
EXCURSIVE MOVEMENT:- movement occuring when mandible moves
away from maximum intercuspation. gpt8
BALANCING SIDE OR NON WORKING SIDE:- the side of mandible
which moves during median line during lateral excursions.
BALANCING INTERFERENCES:- undesirable contacts occuring on
balancing side during lateral movements

6. HISTORY
Mammals evolved from a group of “mammal-like reptiles” about 280 -
190 million years ago.
Reptiles cannot bring their upper and lower teeth together and cannot
chew; their teeth cannot move because they are ankylosed. But by the
time the earliest known mammal had evolved, these now had two sets of
dentitions, and the upper and lower teeth could be occluded.
Diphyodonty (one replacement set, i.e. two dentitions) probably evolved
as a result of the increasing efficiency of the dentition created by the use
and wear of teeth that would shear against each other.
There is no point in producing a succession of such inefficient
dentitions, as every newly erupted molar, because of its high unworn
cusps, would have disrupted the smoothly efficient shearing edges
which are created by attrition

7. Early wear of teeth in a gorilla
Early wear of teeth in a human who lived about 10,000 years
ago. The wear has produced a sharp edge of enamel on the first
molar, which is very efficient for shearing and cutting of coarse
food, and the flatter occlusal surface allows for efficient
grinding. This person was a coastal-dweller, and lived on a
variety of foods, including fish and crustaceans. The other teeth
still have enamel occlusal surfaces.

8. A deciduous dentition also helps to solve the problem of providing a
child with a most effective masticatory apparatus appropriate to their
needs at that time, and consistent with the space available in the jaws.
The potential functional weakness of a transition period is minimised by
the sequence of events: when the central incisors are lost, the
deciduous lateral incisors and canines can be used to incise food,
whilst loss of the deciduous molars does not prevent crushing and
grinding because the first permanent molars are already in place.
The allied development of a gomphosis (periodontal ligament type
attachment) allows the position of each tooth to be adjusted after
eruption, in response to forces produced during chewing, so that it
normally ends up in the most efficient position.

9. DEVELOPMENT OF DENTAL OCCLUSION
Term occlusion is derived from the Latin word, “occlusio”; defined as the
relationship between all the components of the masticatory system in
normal function, dysfunction and parafunction. An ideal occlusion is the
perfect interdigitation of the upper and lower teeth, which is a result of
developmental process consisting of the three main events, jaw growth,
tooth formation and eruption
Occlusal development can be divided into the following development
periods:
• Neo-natal period. (lasts upto 6 months after birth)
• Primary dentition period. (From around the 6th month to 6 years)
• Mixed dentition period. (Around 6 years- 12 years)
• Permanent dentition period (12 years onwards)

10. CONSISTENCY IN PATTERN DEVELOPMENT
Leighton
has shown that the upper anterior gum pad (intercuspid
width) is typically wider than the lower anterior pad,
and the upper anterior gum pad protrudes (overjet)
about 5 mm relative to the lower anterior gum pad.“
The upper anterior gum pad usually overlaps (overbite)
the lower anterior pad by about 0.5 mm. In the first 6
months of postnatal life, there is marked palatal width
increase, and the overjet decreases rapidly.
PRIMARY DENTITION TERMINUS
By 3 years of age, the occlusion of 20 primary teeth is
usually established. The relationship of the distal terminal
planes of opposing second primary molar teeth can
be classified into one of three categories
• FLUSH TERMINAL PLANE
• DISTAL STEP
• MESIAL STEP

12. THE PERMANENT DENTITION

15. In September of 1972, Lawrence F Andrews published an article in the
AJO-DO titled The Six Keys to Normal Occlusion
 Key I – Molar Relationship
 Key II – Crown Angulation (tip)
 Key III – Crown Inclination (torque)
 Key IV – Rotation
 Key V – Tight Contacts
 Key VI – Curve of Spee
KEY 1
According to Andrews’ definition, normal occlusion exists when the
mesiobuccal cusp of the maxillary first permanent molar occludes in
the groove between the mesial and middle buccal cusps of the
mandibular first permanent molar (Figure 3, also known as Class I
dental occlusion).
ADREWS KEYS TO NORMAL DENTAL OCCLUSION
PRESENT IN NATURAL DENTITION

16. KEY 2
The gingival portion of the crowns of all teeth is more distal than the incisal or
occlusal portion of the crowns. The long axis of all crowns of the teeth (with the
exception of the molars) is considered the main mid-development ridge of the
facial surfaces of the teeth. The long axis of the crown of the molar teeth is
considered to be the buccal groove and its extension to the gingiva

17. KEY III – CROWN INCLINATION
This refers to the labio-lingual axial inclination of the anterior teeth
and bucco-lingual axial inclination of the posterior teeth.
KEY IV – ROTATION
The fourth key to optimal occlusion is
absence of tooth rotations
In upper incisors, the gingival
portion of the crown’s labial
surface is lingual to the
incisal portion.
In all other crowns, including
lower incisors, the gingival
portion of the labial or buccal
surface is labial or buccal to
the incisal or occlusal portion.

18. KEY V – TIGHT CONTACTS
There should be no spaces between the teeth. Contact points should abut unless a
discrepancy exists in a mesiodistal crown diameter.
KEY VI – CURVE OF SPEE
The depth of the curve of Spee should be fairly flat ranging from 0.5mm to
1.5mm at its deepest point. An average curve of Spee is 1mm.

19. BIOMECHANICS OF OCCLUSION

28. DIFFERENCES BETWEEN NATURAL
&
ARTIFICIAL OCCLUSION
NATURAL TEETH ARTIFICIAL TEETH
Natural teeth function independently &
each individual tooth disperses the
occlusal load.
Artificial teeth functions as a group & the
occlusal loads are not individually
managed.
Malocclussion can be non-problematic
for long time
Mal occlusion poses immediate drastic
problems
Non-vertical forces are well tolerated Non-vertical forces damages the
supporting tissues
Incising does not affect the posterior
teeth.
Incising will lift the posterior part of the
denture.
The second molar is the favoured area
for heavy mastication and better
Heavy mastication over the second
molar area can tilt or lift the denture
base

29. NATURAL TEETH ARTIFICIAL TEETH
Bilateral balance is not necessary and
usually considered as hindrance.
Bilateral balance is mandatory to
produce stability of denture.
Proprioceptive impulses give feedback
to avoid occlusal prematurities.
This helps patient to have habitual
occlusion away from centric relation
There is no feedback and denture rests
in centric relation .
Any prematurities in this position can
shift the base

30. REVIEW OF LITERATURE
In 1972 Beck listed the uses of different tooth forms into
contemporary occlusal schemes out of which five were
of the nature of a balanced articulation concept and five of
a nonbalanced articulation.
The concept of balanced articulation can be traced back to
Gysi who introduced the 33 degree cusp form teeth. This
anatomic tooth form was followed by a 30 degree posterior
9 tooth form introduced by Pilkington and Turner . These
teeth mathematically designed , were the favorite for
clinicians to develop a balanced occlusal scheme.
Gysi in 1927 proposed the concept of lingualized
articulation. His initial publication was followed by
numerous authors' propsing modifications to this concept.
Payne in 1941 reported on Farmer's posterior teeth setup
that utilised 30 degree cusp form teeth that were reshaped
to the requirementst of lingualized articulation.

31. Following this period Non-anatomic posterior tooth forms
have been introduced. These teeth favor concepts which
utilize non-balanced articulation. Sears was one of the
greatest proponents of this concept. Although initially
these tooth forms were not preferred, since then modified
non-anatomic tooth forms have been introduced which are
more extensively used today.
Pound proposed a non-balanced articulation in which
importance was given to the position of the anterior teeth
to preserve the phonetics and a lingualised occlusal
scheme to allow increased denture efficiency and stability
in the chewing cycle
Jones in 1972 proposed the concept of monoplane
articulation This concept includes a non-anatomic
occlusal scheme with a few specific modifications. With
the introduction of 0 teeth, the monoplane scheme has
become popular in certain patients requiring complete
dentures.
Bonwill in 1858 described the equilateral triangle theory based on a points of
occlusal balance.

32. MacMillan based on his studies suggested a
shift from bilateral balanced occlusion to unilateral
balanced occlusion while restoring both natural and
prosthetic dentitions.
He observed that bilateral balanced occlusion commonly
did not exist in nature. His evidence was based on the
evaluation of “various types of masticatory excursions of
lower animals.”
Swoope in 1990 studied the effect of cusp form & occlusal surface
area on denture base deformation
Nimo in 1994 described method for developing balancing ramps in
complete dentures with non anatomic teeth

33. CONCEPTS OF OCCLUSSION
Unlike natural teeth, the artificial teeth act as a single unit. Hence,
there should minimum of three contact points ( usually one anterior
and two posterior) for the even distribution and stabilization of denture
at any position of mandible.
Complete denture occlusion varies with type of the teeth selected.
Anatomic teeth should be arranged in balanced occlusion and non
anatomic teeth should be arranged in monoplane occlusion
ALL THE OCCLUSAL FORMS SHOULD HAVE TRIPD CONTACT
IN CENTRIC RELATION
All the occlusal forms are based on different concepts of
occlusion
Which are:-
: spherical concept of occlusion
: organic concept of occlussion
: neutrocentric concept of occlusion

34. SPHERICAL CONCEPT OF MONSON
Proposed by Dr. George S. Monson in 1920.
An ideal curve of occlusion in which each cusp and
incisal edge touches the surface of an imaginary sphere 8
inches in diameter.

35. ORGANIC CONCEPT OF OCCLUSION
Here, existing shape of the teeth are altered to have the cusps suitable for the
patient comfort and harmony during movement of mandible during function.
 Movement of the condyle determines the direction of the ridges and
grooves of the teeth
 And mandibular movements determines theother factors like cusp height,
fossa, depth of the fissure and concavity f the lingual surface.
In organic or organized occlussion the aim is to relate the occlusal
surfaces of the teeth so that teeth are in harmony with the muscles and
joints during function
NEUTROCENTRIC CONCEPT OF OCCLUSION
Here the plane of occlusion should be flat and parallel to the residual alveolar
ridge. There is no antero-posterior, bucco lingual inclines for the posterior
teeth. ( like monoplane occlusion)
Term neutrocentric denotes an occlusion that eliminates the anteroposterior
and buccolingual inlines to direct the forces to posterior teeth

36. SEARS AXIOMS OF COMPLETE DENTURE OCCLUSION
SEARS published the following factors to be considered that helps
plan the complete denture occlusion:
• Smaller the area of the occlusal surface, lesser the occlusal load
going to supporting tissue i.e. bone.
• Vertical force in tilted occlusal surface produce non-vertical
force on the denture.
• Vertical force acting outside the ridge crest will produce tipping
of the denture.
• Vertical forces on the denture base lyin over the resilient tissues
will produce lever forces on the denture

38. OCCLUSAL SCHEMES REQUISITES TO FULLFILL THE REQUIREMENTS
Occlusal schemes has three requisites
1. Incisive units
2. Working units &
3. Balancing units
INCISIVE UNITS
Includes all four incisors
a) Sharp units for increased incising efficiency
b) Units should not contact during mastication, they should only
contact during protrusion
c) Shallow incisal guidance
d) Increased horizontal overlap to avoid interference during settling (
the mandibular denture may slide anteriorly as it settles)
WORKING UNITS
a) Cusps for good cutting and grinding efficiency
b) Smaller buccolingual width to decrease the occlusal load
transferred to the tissues
c) Group function at the end of the chewing cylce during eccentric
position

39. d) The occlusal load should be directed to the anteroposterior centre
of the denture
e) The plane of occlusion should be parallel to the mean foundation
plane of the ridge
BALANCING UNITS
a) Second molars should be in contact during protrusive action
b) They should have contact with the working side at the end of the
chewing cycle
c) Smooth gliding contacts should be available fo uninterfered lateral
and protrusive movements.

40. “Occlusal scheme is defined as the form and the arrangement of the
occlusal contacts in natural and artificial dentition.”
The pattern of occlusal contacts between opposing teeth during
centric relation and functional movement of the mandible will be
determined by the occlusal schemes.
The quantity and the intensity of these contacts determine the amount
and the direction of the forces that are transmitted through the bases
of the denture to the residual ridges.
That is why the occlusal scheme is an important factor in the design
of complete denture prosthesis.

41. OCCLUSAL SCHEMES HAVE BEEN CLASSIFIED INTO:
 NEUTROCENTRIC OCCLUSION
 LINGUALIZED OCCLUSION
 NON ANATOMIC OCCLUSION (MONOPLANE
OCCLUSION WITH BALANCE)
 LINEAR OCCLUSION
 BALANCED OCCLUSION

42. BALANCED OCCLUSION :
“The bilateral, simultaneous, anterior and posterior occlusal
contact of teeth in centric and eccentric positions .”
It is not seen in natural dentition.
Characteristic requirements of balanced occlusion:
• All the teeth of the working side (central incisor to
second molar) should glide evenly against the
opposing teeth.
• No single tooth should produce any interference or
disocclusion of the other teeth.
• There should be contacts in the balancing side, but
they should not interfere with the smooth gliding
movements of the working side.
There should be simultaneous contact during protrusion

43. IMPORTANCE OF BALANCED OCCLUSION :
Balanced occlusion is one of the most important factors
that affect denture stability, absence of occlusal balance
will result in leverage of the denture during mandibular
movement.
Sheppard stated that, “Enter bolus, Exit balance” according
to this statement, the balancing contact is absent when
food enters the oral cavity. This makes us think that
balanced occlusion has no function during mastication;
hence, it is not essential in a complete denture, but this is
not true.
On an average, a normal individual makes masticatory
tooth contact only for 10 minutes in one full day compared
to 4 hours of total tooth contact during other functions. So,
for these 4 hours of tooth contact, balanced occlusion is
important to maintain the stability of the denture.
Hence, balanced occlusion is more critical during
parafunctional movements

44. GENERAL CONSIDERATIONS FOR BALANCED OCCLUSION

45. TYPES OF BALANCED OCCLUSION
Occlusal balance or balanced occlusion can be classified as
Follows
• UNILATERAL BALANCED OCCLUSION
• BILATERAL BALANCED OCCLUSION
• PROTRUSIVE BALANCED OCCLUSION
• LATERAL BALANCED OCCLUSION
UNILATERAL BALANCED OCCLUSION:
This is a type of occlusion seen on occlusal surfaces of teeth
on one side when they occlude simultaneously with a
smooth, uninterrupted glide. This is not followed during
complete denture construction. It is more pertained to
fixed partial dentures.

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

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

48. LATERAL BALANCED OCCLUSION
Minimal 3 point contact during lateral movement of the mandible.
Absent in normal dentition.
Factors :
• Angle of inclination of condylar path.
• Angle of incisal guidance.
• Angle of inclination of plane of occlusion
• Compensating curves.
• Buccal & lingual cusp height.
• The Benett side shift on the working side

50. CONCEPTS PROPOSED TO ATTAIN BALANCED OCCLUSION

53. NINE FACTORS GOVERNING THE ARTICULATION ARE CALLED AS
“HANAU’S LAWS OF ARTICULATION”
 Horizontal condylar guidance
 Compensating curve
 Protrusive incisal guidance
 Plane of orientation
 Buccolingual inclination of the tooth axis
 Sagittal condylar pathway
 Sagittal incisal guidance
 Tooth alignment
 Relative cusp height

54. Hanau later condensed these nine factors and
formulated five factors which are commonly
known as Hanau’s Quint:
-Condylar Guidance
-Incisal Guidance
-Compensating curves
-Relative Cusp Height
-Plane of Orientation of occlusal plane

56.  Trapozzano reviewed Hanau’s five
factors and decided that only three
factors were concerned with
balanced occluson.
 He eliminated the plane of orientation
and compensating curve inclination
TROPOZZANO’S CONCEPT

57. BOUCHER’S CONCEPT
Carl O Boucher analyzed Trapazzano’s work and stated his own
concepts and ideas as follows:-
 There are three fixed factors of balanced occlusion, the orientation
of the occlusal plane, the incisal guidance and the condylar
guidance.
 The angulation of certain cuspal inclines is more important than
the height of the cusps.
 Boucher felt that the compensatory curve is important since it
helps in increasing the effective height of the cusps without
changing the form.
 Boucher’s disagreed with Trapazzano that the occlusal plane could
be located at various heights to favour a weaker ridge and
recommended that the plane be orientated exactly as when natural
teeth were present.

58. LOTTS’S CONCEPT
He clarified the laws of occlusion by relating them to the posterior
separation that is the resultant of the guiding factor. He stated the laws as
follows
 The greater the angle of condyle path, the greater is the posterior
separation.
 The greater the angle of overbite, the greater is the separation in
the anterior region and the posterior region

59.  The greater the separation of the posterior teeth the greater or higher must
be the compensating curve.
 Posterior separation beyond the balancing abiltiy of the compensating curve
can be balanced by the introduction of the plane of orientation.

60.  The greater the separation of the teeth, the greater must be the height of the
cusps of posterior teeth.
 He simplified the hanau’s quint using following chart

61. BERNARD LEVIN’S CONCEPT
• He believed that it was not necessary to consider plane of occlusion
because it was not very useful practically.
• He also stated that plane of occlusion can be altered 1-2mm to increase
the stability of denture
He named the other four factors as “QUAD” which are as follows:-
 The condylar guidance is fixed and is recorded from the patient.
 The incisal guidance is usually obtained from patients esthetic and
phonetic requirements
 The compensating curve is the most important factor in obtaining
occlusal balance.
 Cusp teeth have the inclines necessary for balanced occlusion but
nearly always used with a compensating curve

63. FACTORS INFLUENCING BALANCED OCCLUSION
(1) INCLINATION OF THE CONDYLAR
PATH.
(2) INCISAL GUIDANCE.
(3) ORIENTATION OF THE PLANE OF
OCCLUSION
(4) CUSPAL ANGULATION.
(5) COMPENSATING CURVE.

64. 1). CONDYLAR GUIDANCE
Recorded from the patient using protrusive registration.
The interocclusal records are transferred to the articulator and then
accomodated to glide freely into position.
Mechanics: Increase in the condylar guidance will increase the jaw
separation during protrusion. This factor cannot be modified. So in
patients with steep condylar guidance incisal guidance is decreased
to prevent the posterior jaw separation.

65. Components of condylar guidance
a).Horizontal condylar guidance-guides the forward
movement for protrusive balance.
b).Lateral condylar guidance-guides the sideward or lateral
movement of the mandible.

67. INCISAL GUIDANCE
Defined as “ influence of contacting surfaces of maxillary and
mandibular teeth during mandibular movements”
Component of incisal guidance:
1). Horizontal component
2). Vertical component

68. • It is the second factor of balanced occlusion.
• It is determined by dentist during anterior try in.
• It should be set according to desired overjet and overbite of the
patient.
During protrusive movements movement of mandibur teeth is
guided by the palatal surfaces of the maxillary teeth which is
called incisl guidance or protrusive path.

70. 3). PLANE OF OCCLUSION OR OCCLUSAL PLANE-
Defined as “An imaginary surface which is related anatomically to the
cranium and which theoretically touches the incisal edges of the incisors
& the tips of the occluding surfaces of posterior teeth. It represents the
mean curvature of the surface.
Established anteriorly by height of lower canine and
posteriorly by height of retromolar pad.
Parallel to campher’s line & tilting of the plane >10o is not advisable

71. 4). COMPENSATING CURVE
“The anterioposterior and lateral curvatures in the alignment of
the occluding surfaces and incisal edges of artificial teeth
which are used to develop balanced occlusion”
Determined by inclination of posterior teeth and their vertical
relationship to occlusal plane
Two types
a) anteroposterior compensating curve
b) Lateral compensative curve

72. ANTERIOPOSTERIOR COMPENSATING CURVES
CURVE OF SPEE
“ Anatomic curvature of the occlusal alignment of
teeth beginning at the tip of lower canine and
following the buccal cusps of the natural premolars
and the molars, continuing to the anterior border of
the ramus” as described by Graf Von Spee

73. SIGNIFICANCE - WHEN THE PATIENT MOVES HIS MANDIBLE
FORWARD, THE POSTERIOR TEETH SET ON THIS CURVE WILL
CONTINUE TO REMAIN IN CONTACT.THUS AVOIDING
DISOCCLUSION

74. Posterior teeth separation when the curve of spee
not incorporated
Incorporating the curve spee will provide posterior tooth
contact during protrusion

75. LATERAL COMPENSATING CURVES
a).Compensating curve for Monson curve
“ The curve of occlusion in which each cusp and incisal edge
touches to a segment of the sphere of 8” in diameter with its center
at glabella”-GPT
runs across the palatal & buccal cusps of maxillary molars.

76. B). WILSON’S CURVE
“In the mandibular arch, that curve, as viewed in the frontal plane,
which is concave above and contacts the buccal and lingual cusps of
the mandibular molars; In the maxillary arch, that curve, as viewed in
the frontal plane, which is convex below and contacts the lingual and
buccal cusps of the maxillary molars. The facial and lingual cusp tips
on both sides of the dental arch form the curve.” -GPT
This curve is followed when first premolars are arranged. The
premolars are arranged according to this curve so that they do not
produce any interference to lateral movements.

77. C). PLEASURE CURVE/ REVERSE CURVE
“A helicoid curve of occlusion that, when viewed in the frontal plane,
conforms to curve that is convex from the superior view, except for the last
molars which reverse that pattern.”-GPT
Lateral view with 2nd PM & 1st molar
follow the reverse curve
Reverse curve is used in the bicuspid
area for lever balance

78. 5). CUSPAL ANGULATION

80. Advantages of balanced occlusion :
• Bilateral simulataneous contact help to seat the dentures in a stable
position during mastication, swallowing and maintain retention and
stability of the denture and the health of the oral tissues.
• cross-arch balance.
• Denture bases are stable even during bruxing activity.
Disadvantages of balanced occlusion
• It is difficult to achieve in mouths where an increased vertical incisor
overlap is present – Class II cases.
• It may tend to encourage lateral and protrusive grinding habits.
• A semi adjustable or fully adjustable articulator is required.

81. NEUTROCENTRIC OCCLUSION
Neutrocentric occlusion is at the far right of the occlusal spectrum and the
exact opposite of the anatomic occlusion, was developed by De van.
De Van coined the term neutrocentric to embody the two
key objectives of his occlusal scheme,
1. The neutralization of inclines.
2. The centralization of forces which act on the basal seat
when the mandible is in centric relation to the maxillae
There are five elements in this occlusal scheme:
• Position
• Proportion
• Pitch
• Form
• number

82. POSITION:
• Positioned the posterior teeth over the posterior residual ridge as
far lingually as the tongue would allow, so that forces would be
perpendicular to the support areas.
PROPORTION:
• Reduction of tooth width upto 40%.
• Reduced vertical stress on the ridge by narrowing the occlusal
table.
• Forces were centralized without encroachment on the tongue
space.
PITCH:
• Pitch or inclination or tilt
• There was no compensating curve and no incisal guidance.
• This positioning directed forces perpendicular to the mean osseous
foundation plane.

83. FORM:
• Flat teeth with no deflecting inclines• Reduced destructive lateral
forces and helped to keep masticatory forces perpendicular to the
support.
• Reduced destructive lateral forces and helped to keep masticatory
forces perpendicular to the support.
NUMBER:
• The posterior teeth were reduced in number from eight to six.
• This decreased the magnitude of the occlusal force and centralized
it to the second premolar and first molar area.

84. ADVANTAGES :
• Technique is simple and requires less precise records.
• Ideal for a patient who have resorbed friable ridges.
• By removing inclines, the lateral forces, which are very
destructive to the residual ridges, are reduced.
• Because the neutrocentric technique provides an area
of closure and does not lock the mandible into a single
position. Ideal for Geriatric patient with limited oral
dexterity.
• It is especially good for Class II (retrognathic), Class III
(prognathic) and crossbite cases.
DISADVANTAGES
• It is the least esthetic of the five basic occlusal schemes.
• Moving the teeth lingually and altering their vertical
position may not be compatible with the tongue, lip and
cheek function.
• Impair mastication because of poor bolus penetration
• This flat type of occlusion cannot be balanced
When using this concept of occlusion the patient is instructed not to
incise the bolus, with this tooth arrangement Devan noted that “the
patient will become a chopper, not a chewer or a grinder”

85. LINGUALIZED OCCLUSION
Concept was introduced by Alfred Gysi in 1927
S.H. Payne (1941): 'cusp-to-fossa occlusion'
Pound: 'lingualized occlusion'
“Lingualized occlusion can be defined as, the form of
denture occlusion that where the maxillary lingual cusps
articulate with the mandibular occlusal surfaces in centric
working and non-working mandibular positions.”

89. Lingualized occlusion should not be confused with
placement of the mandibular teeth lingual to the ridge crest
Indications :
• When patient places high priority on esthetics but oral
conditions indicate a non-anatomic occlusal scheme
such as:
 Severe alveolar resorption
 Class II jaw relationship
 Displaceable supporting tissues.
• When a complete denture opposes a removable partial
denture.
• When a more favorable stress distribution is desired in
patients with parafunctional habits.

90. ADVANTAGES :
• Lingualized occlusal concept is a simple technique requiring less
precise records than fully balanced occlusion and is similar in
requirements to nonanatomic teeth set on a curve.
• Most of the advantages attributed to both anatomic & non-anatomic
forms are retained.
• Cusp form is more natural in appearance compared to non-anatomic
tooth form.
• Good penetration of food bolus is possible. This may reduce the
lateral chewing component.
• Vertical forces are centralized on mandibular teeth & it provides an
area of closure, allowing easier accommodation to unpredictable
basal seat changes.
• With lingualized occlusion, additional stability is imparted to the
denture during parafunctional movements when balanced occlusion
is used
• Can be used in Class II, Class III & cross-bite situations

91. DISADVANTAGES :
Wear of maxillary lingual cusp or mandibular fossa
rapidly results in buccal and lingual contact of equal
intensity results in negotiation of centralization of forces
on the mandibular posterior teeth and increase the like
hood of lateral displacement.

92. MONOPLANE OCCLUSION
Sear introduced monoplane occlusion with balancing
ramps or tooth at the distal part of the mandibular arch
which comes in contact only in eccentric excursions
De Van has used the same principle without the balancing
Ramp.
According to this concept teeth which are flat mesiodistally
and buccolingually are used, oriented as close as possible
parallel to the maxillary and mandibular mean foundation
plane.

94. MONOPLANE ARTICULATION:-
Anterior teeth make contact in excursions (christensens
phenomenon)
Modifications have been made to minimize the tilting potential
• Balancing ramps
• Compensating curves

95. MONOPLANE OCCLUSION WITHOUT CONDYLAR INFLUENCE

96. INDICATION :
• Abnormal closure imbalance, pathosis, trauma,
neuromuscular disturbances.
• Posterior displaceable mucosa.
• Multilated, tortuous ridges with an excessive denture
space .
• Ridges are flat or knife edge, rendering dentures more
suspectible to horizontal force.
• When chewing pattern is milling type with broad
excursions.
• Maximum of vertical force and a minimum of horizontal
stress is desired .
• The amount of horizontal overlap is determined by jaw
relation, ranges from 0mm (edge to edge) Class III
relation to as much as 12mm for severe class II relation
Usually the mandibular second molar will be placed on the
molar slope area, called 'skid row'.
In this the occlusal surface of the maxillary second molar
set parallel to the occlusal surface of the mandibular
second molar but 2 mm above the occlusal plane, well out
of occlusion.

97. Monoplane occlusion can be balanced by following
methods:
• Incline the mandibular second molar to provide contact
with the maxillary denture in all excursions, the maxillary
second molars are similarly inclined but left out of centric
contact.
• The use of customized balancing ramp placed
distal to the mandibular second molar. Ramp provides
tripodal effect of contacts of denture bases.In eccentric
relation, there is smooth contact anteriorly on teeth and
posteriorly on the balancing ramp. Balancing ramp
improves horizontal stability of the denture.

98. ADVANTAGES :
• They are more adaptable to the unusual jaw relation
such as class II and class III relations, used easily in cases
of variations in the width of maxillary and mandibular
jaws, cross bite.
• These impart a sense of freedom to the patients, do not
lock mandible in one position.
• They eliminate horizontal forces, more damaging than
vertical forces.
• Because the monoplane teeth occlude in more than one
relationship, so centric relation developed to an area
instead of a point.
• Monoplane teeth permit the use of a simplified and less
time consuming technique and offer greater comfort
and efficiency for a longer period.
• They accommodate better to the negative changes in
the ridge height that occur with aging

99. DISADVANTAGES :
• No vertical component to aid in shearing during
mastication.
• Patients may complain of lack of positive
intercuspation
position.
• Esthetically limited.
• Occlude only in two dimensions, but the
mandible has a
3D movement due to its condylar behavior

102. CONCLUSION
Many occlusal schemes have been proposed
over the years. Most schemes when correctly
used gives satisfactory results. The result is
satisfactory, if the patient gets better function,
esthetics & comfort without any adverse
changes in denture foundation.

103. REFERENCES