Complete Denture Occlusion 3- Factors affecting Balanced Occlusion

3. Dr. Amal Fathy Kaddah
Prof. of Prosthodontic,
Faculty of Oral & Dental Medicine,
Cairo University

5. Occlusion in complete denture must
be developed to function efficiently
and with the least amount of
trauma to the supporting tissues.

6.  Preservation of the remaining tissues
 Proper masticatory efficiency
Enhancement of denture stability,
retention and support
 Enhancement of phonetics and esthetics
ObjectivesObjectives

7. Anterior
determinants of
occlusion
Posterior determinants
of occlusion
The determinants of occlusion

8. 1. The condylar guidance
2. The incisal guidance
3. The inclination of plane
of occlusion
4. The compensating
curve and
5. cusp angle of teeth
(Cuspal inclination)

9. Rotation occurs when the
mandible makes a hinged
movement. (the head of the
condyle rotates around an
imaginary axis)
Translation occurs when the
mandible moves into a
protrusive or lateral position, or
a combination of the two
(bodily movement of the head of
the condyle)
The movements of the condyle in the
glenoid fossa are either:

10. No TranslationNo Translation
A- Rotation occurs when the head of the
condyle rotates around an imaginary
axis

11. TranslationTranslation
B. Translation is the bodily movement of the head of the condyle

12. The angle formed by the steepness of the
articulator surface of the Temporal bone as
related to a horizontal plane
The condylar guidance is the only factor
given by the patient
1- Condylar inclination

13. Condylar Guidance
Angle
The angle formed by an
imaginary horizontal line
at the superior head of
the condyle and the path
that the condyle will
pass through during
function
Varies from individual to
individual because of
anatomical differences

14. 1. The shape of the glenoid
fossa.
2. The variation of the
thickness of the
articular disc in its
different parts.
3. The relation of the
condyle to the disc
during movement.
4. The extent of
mandibular protrusion
The inclination of the condylar paths varies in
different individuals and from side to side in
the same person. It depends upon

15. Condylar path inclination varies according
to the amount of protrusion. a-b Sagittal condylar path
inclination. Centric relation position of the condyle.
4-P. 4 mm protrusion.8P. 8 mm protrusion

16. The condylar guidance: refers to the
path of the condyle follows in the
temporomandibular joint when the
mandible moves into protrusive or lateral
Balancing side.
Condyle has downward path
Working side.
Condyle pivots.

17. Bennett AngleBennett Angle
The angle formed by the
sagittal plane (assumed
straight protrusive path)
and the path of the
advancing (orbiting)
condyle during lateral
mandibular movements
as viewed in the
horizontal plane.
Balancing side. Working side.

18. • Working side: (Mandible moving
toward the cheek)
• Balancing side: (Mandible moving
toward the tongue)
• Working side condyle pivots within the
socket and is better supported.
• Balancing side condyle has a downward
orbiting path. It is traveling a greater
distance in ‘space’ and is more prone to
injury or damage.

19. If the condylar angle is
steep, its difficult to
produce balance
occlusion because when
the condyle travel
downward and forward;
large space is created
posteriorly when the
anterior teeth are edge
to edge. So,
compensation should be
made by altering the
other factors to obtain

20. Means that when the patient produce a
protrusion with well adapted occlusal
rims, there will be a v- shaped gap
between the rims in the molar region.
Sagittal Christensen phenomenon

21. Means that when the patient
produce a lateral excurtion
with well adapted occlusal
rims, there will be a v shaped
gap between the rims in the
molar region on the balance
side. On the working side there
will be contact between the
upper and the lower rims.
The Transversal Christensen
phenomenon

22.  Ease of determination
 Used to set condylar
guidance
 Helps setting teeth
for best occlusal
contacts
Protrusive RecordsProtrusive Records
To Set Condylar InclinationTo Set Condylar Inclination

23. Protrusive RecordsProtrusive Records
To Set Condylar InclinationTo Set Condylar Inclination
 Material must interdigitate
with the opposing “V-
shaped” notches
 Record should cover entire
rim surface.
 Condylar elements are released from hinge
position (unlocked).
 Instrument protruded, and the rims closed into

24. Horizontal condylarHorizontal condylar
guidanceguidance

25. Prior to Mounting
• Ensure
– Only wax-rim to wax-rim contact
– Casts should not contact
– Record bases should not contact
– If other contacts, mounting will be
incorrect

26. Adjust Protrusive Guide for
Maximal Interdigitation

27. The C.G. of articulator is an appropriated duplication of
the C.G. in the patient and is obtained by means of a
protrusive record. So that the patient's
temporomandibular joint is in harmony with the occlusion
as programmed on the articulator

28. The occlusion rims are reestablished and checked for 3mm.
Clearance in a protrusive excursion

31. After protrusive record
making the same procedure
is followed, however the
patient is asked to move his
mandible to left and right
and getting
Right and left lateral relation
him to bite on wax wafer, two records are made,
one for left and one for right. These records are
used to adjust the lateral condylar inclination.

32. In Hauau
articulator
Hanan equation
can be used
L = H/ 8+ I2

35. It is the path taken by the
lower anterior teeth as it
move in protrusive
movements against the
palatal surface of upper
anteriors till become edge
to edge.
2-The incisal guidance
It’s the influence of the contacting surfaces
of the mandibular & maxillary anterior teeth
on mandibular movement

36. The influence
of the
contacting
surfaces of the
guide pin and
The incisal guidance of the
articulator
guide table on articular
movement.

37. Relation
between the
incisal path of
patient and
incisal
guidance of
articulator

38. Incisal Guidance Angle
The angle formed by the
intersection of the plane of
occlusion and a line within
the sagittal plane
determined by the incisal
edges of the maxillary and
mandibular central incisors
when the teeth are in
maximum intercuspation
HO

39. The incisal inclination is
called the incisal
guide angle and the
influence that this angle
has on mandibular
movements is termed
incisal guidance.

40. Incisal Guidance Angle
This angle varies directly with the
vertical overbite and inversely with
the horizontal overjet
This angle is set to 10˚ in CD and
not exceeding 20˚

41. ↓ Incisal Guidance Angle
by either:
↑ Horizontal overlap
↓ Vertical overlap
Incisal Guidance

42. The incisal guide angle can be controlled
when developing a balanced occlusion. With a given
amount of vertical overlap (VO) the incisal guide angle
can be made flatter by increasing the horizontal overlap (HO)

43. It can also be made less steep by reducing VO
A- Steep incisal guidance
B. Medium incisal guidance
C. Zero incisal guidance
B

44. Incisal Guidance
• For CD, the incisal
guidance should be as
shallow as esthetics
and phonetics
will Permit when arrangement of anterior teeth
to reduce protrusive displacing forces

45. A) The esthetic factor dictated a steep vertical
overlap with little horizontal overlap. Therefore,
steeper posterior cuspal inclines had to be selected.
(B) In eccentric movements the inclinations of the
posterior cusps must be sufficient to prevent
anterior interference

46. A- The esthetic factors allowed for an adequate
amount of horizontal overlap, so the shallow
cuspal inclines could be selected.
B- In eccentric movement the shallow
posterior inclines are sufficient to prevent
anterior interference

48. I.G. should be either equal to or less than C.G.
I.G. SHOULD NEVER BE GREATER THAN C.G.

49. Anterior interference
I.G. GREATER THAN C.G
X

50. Excursive Movements
Centric
occlusion
Protrusive
The mandible moves essentially forward and the occlusal
contacts are smooth and simultaneous in the posterior
both on right and left sides and on the anterior teeth.

51. Excursive Movements
Centric
occlusion
Protrusive
Anterior
interference

52. •I.G. can be set by the
dentist according to
esthetics and phonetics
requirements.
but in no case should
I.G. exceed that
of the C.G.

53. If Increased Incisal
Guidance Angle For
CD?
During
protrusion:
Upper denture drops at
the back
Lower denture slides
backward

54. C.C. to effect an occlusal
balance.
• This type of occlusion is
detrimental to the stability
and equilibrium of the denture
base.
Steep I.G. results in harmful
inclined planes with their
harmful risk to the supporting
tissues

55. O. P. is formed
by lines
connecting tips
of incisor teeth
and distobuccal
cusps of the
most posterior
teeth on each
side of arch
3- The Plane of Occlusion
(Plane of Orientations)

56. The occlusal plane
is parallel to the
ear nose plane
The occlusal plane
is parallel to the
interpupillary line
3- The Plane of Occlusion

57. Its inclination can be altered slightly to a maximum of 10o
It is established anteriorly by the height of the lower
canine, which nearly coincides with the commisure of
the mouth and posteriorly by the height of the retro
molar pad. It is usually parallel to
Camper’s line.
It is not as important as
other factors
3- The Plane of Occlusion
(Plane of Orientations)

58. 1- Aesthetic base
2- Functional base (chewing and speech)
3- Physical and mechanical (leverage
action and parallelism).
Factors must be consideredFactors must be considered::
Determination of the occlusal plane

59. O.P. At (a) is the
ala-tragus plane
obtained from the
patient. At (b) is a
compromise plane
midway between
ridges. At (c) is a
low plane
necessary to favor
weak lower ridges

60. •The orientation of the occlusal
plane becomes a fixed factor of
occlusion
•Any necessary alteration for
balancing the occlusion must
therefore be made on other factors
affecting the occlusion (that is,
the cuspal inclination or the
prominence of the compensating
curve)
3- The Plane of Occlusion

61. Effect of plane of occlusion on cusp height

62. Effective Cusp angle
When we select a tooth with a certain cusp height or angle, it
doesn’t mean anything until the tooth is positioned in the
denture. For example, a particular tooth may be manufactured
with a 20 degree inclination. However, by tilting the tooth in
relation to the mean occlusal plane, one may create an
effective inclination of greater or less than 20 degrees.
CA
20o
CA
20o
Tilt
5o
Tilt
5o
5o
Angle of O. plane
Plane of occlusion
horizontalECA 25o ECA 25o
• CA: Cusp Angle
• ECA: Effective Cusp angle
= CA 20o
+ Angle of plane of
occlusion (5o
) = (25o
)

63. 4- Compensating curves
Artificial curves introduced into
complete denture are among the
most important determinants in
establishing a balanced occlusion so
that the occlusal surface results in a
curve that is in harmony with the
movement of the mandible as guided
posteriorly by the condylar path

64. 1- Spee’s curve
The anatomic curvature of the occlusal alignment
of the lower teeth beginning at the tip of the
lower cuspid and following the buccal cusps of
the natural bicuspids and molars continuing to the
5- Compensating curves

65. The buccal cusps of
the lower posterior
teeth are slightly
higher than the
lingual cusps, and a
line drawn through
the buccal and
lingual cusps of the
teeth on the other
side forms a lateral
2- Wilson’s curve

66. A proposed ideal curve of occlusion the curve of occlusion
in which each cusp and incisal edge of upper and lower
teeth of right and left sides touches or conforms to a
segment of the surface of a sphere eight inches in diameter
its center in the region of the Glabella
3- Monson’s curve

67. The compensating curve of the
artificial occlusion corresponds
to a combination of these curves
in natural teeth.
It is considered one of the most
important factors in establishing
balanced occlusion

68. Compensating Curves
•The steepness of the curve necessary to
achieve balance is the result of guiding
influence of angle of condylar guidance and
angle of incisal guidance.
•A lesser compensating curve for the same
condylar guidance would result in a steeper
incisal guidance (anterior interference), which
would cause loss of molar balancing contacts.

69. Compensating Curves
•It is functionally and mechanically
advantageous to keep compensating
curve as modest as possible → This
is accomplished by setting as
shallow an incisal guidance as
phonetics, esthetics permit

70. It is measured by
the angle formed
by the
mesiobuccal
cuspal incline to
the horizontal plan
when the long axis
of the tooth is
vertical to the
plane
Cusp Angle
4-4- Cusp Height (inclination of cusplessCusp Height (inclination of cuspless
teeth)teeth)

71. A steep condylar guidance necessitates teeth with steep cusps.
Cusp height is therefore an important determinant as it modifies
the effect of occlusal plane and compensating curves.

73. • Steep I.G. calls for steep cusps, steep
O.P. or a steep C.C. to effect an occlusal
balance. The angle of this movement is
governed by the cusp angles and hence
the lower incisors will move at the same
angle as the lower molars

74. Cusp Angle

75. Hanau in 1926 formulated laws of balanced
articulation (called Hanau’s quint(.
Hanau’s articulation Quint
Arrow pointing
away from center
indicates increasing
values
Arrow pointing
toward center
indicates decreasing
values

76. C= Condylar Inclination x Incisal Guidance
Occ. Plane x Cuspal Inclination x Comp. Curve
Hanau’s Quint
• The five factors of balanced occlusion related to one
another on a balance beam.
• To keep the occlusion in balance is a simple procedure
once the factors are related this way
• Within the confines of esthetics and phonetics, minimize
Incisal Guidance in Complete Dentures to minimize
inclined tipping forces
(1926)

77. Condylar
guidance
Incisal
guidance
Occlusal
Plane
Cusp
Height
Compensating
curve
Theilmann’s Formula
The five factors of balanced occlusionThe five factors of balanced occlusion
related to one another on a balancerelated to one another on a balance
beam. To keep the occlusion in balancebeam. To keep the occlusion in balance
is a simple procedure once the factorsis a simple procedure once the factors
are related to this wayare related to this way

78. Condylar
guidance
Incisal
guidance
Occlusal
Plane
Cusp
Height
Compensating
curve
Theilmann’s Formula
* The incisal guidance and inclination of the plane
of occlusion: can be altered within a small range
according to esthetic and phonetic and anatomical
factors.

79. As the mandible is protruded its position is
controlled by the incisal guidance and the
condylar path. The center elements
affecting balance, namely the plane of
occlusion, the cusp inclines, and the
compensating curve, can be adjusted to
harmonize. Their relationship to one
another is easily recognized if this diagram
is reproduced as a cutout for actual
manipulation.

88. The dentist can onlyThe dentist can only
control four of fivecontrol four of five
factorsfactors..
* The condylar guidance: can be completely
fixed and is not his to change.
* The incisal guidance and inclination of the
plane of occlusion: can be altered within a
small range according to esthetic and physiologic
(phonetic)and anatomical factors.
* Cusps on the teeth and tooth inclination of
cuspless teeth and compensating curve: are the
real working tools of balanced occlusion.

89. • Steep I.G. calls for steep cusps,
steep O.P. or a steep C.C. to
effect an occlusal balance.
• This type of occlusion is
detrimental to the stability and
equilibrium of the denture base.
Steep I.G. results in harmful
inclined planes with their
harmful risk to the supporting
tissues
According To The FormulaAccording To The Formula

90. • To achieve balanced occlusion: For
high condylar guidance we need to
have high compensating curve,
occlusal plane and cuspal height.
• To achieve balanced occlusion: For
high incisal guidance we need to have
high compensating curve, occlusal
plane and cuspal height.
According To The FormulaAccording To The Formula

91. To achieve balanced occlusion,
the steeper the condylar
guidance, the greater the cusp
height toward the posterior
or the steeper the
compensating curves
According To The FormulaAccording To The Formula

92. To achieve balanced
occlusion, the steeper the
compensating curves,
the less the cusp height toward
the posterior
According To The FormulaAccording To The Formula

93. Bilateral Balanced Lingualized Occlusion
Protrusive
Balancing SideWorking Side
Centric Occlusion

94. Two figures with the same condylar inclination but
different incisal guide inclinations. A, Steep vertical
overlap, with resultant steep cusp inclines. B, Less
incisal angle, with resultant flatter cusp inclines
a b

95. Two figures with different condylar inclinations and different incisal guide
inclinations. a, Less condylar inclination with Steep vertical overlap, with
resultant flatter cusp inclines. b, Steep condylar inclination with Less
incisal angle, with resultant steep cusp inclines or Steepen the
compensating curves
ba
The condylar guidance has great influence in the second molar region and
progressively less till the incisor region.
X

96. Question
Q) Suppose that the incisal guidance is set and the condylar
guidance is steeper than your chosen 20 degree teeth. To
obtain balanced occlusion in your complete denture, what
should you do?
a. Steepen the compensating curves in both sagittal and
frontal planes
b. Steepen the compensating curves in only sagittal but not
frontal plane
c. Decrease the inclination of occlusal plane
d. Decrease the steepness of compensating curves in both
sagittal and frontal planes
e. Steepen the condylar guidance
f. None of the above

97. Concepts of
Occlusion for
complete denture
Next lecture

98. Everything is
okay in the end
If it's not okay,
then it's not
the end

100. THANK
THANK
YOU
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