Removable Prosthodontics

3. • The stomatognathic system.
• What 'occlusion' is and why it is important.
• Definitions.
• The significance of 'ideal occlusion‘.
• Difference between natural and artificial occlusion.
• Mandibular Movements.
• Articulators and Facebows.
• Balanced occlusion and factors affecting balanced occlusion.
• Concepts of occlusion (Balanced and Non balanced Occlusion).
• Recording of occlusal relations for removable prosthodontics.
• Occlusal correction for removable prosthesis.
• Removable partial denture occlusion.
Occlusion Outline

4. STOMATOGNATHIC SYSTEM
• The movement of the jaw is orchestrated OR
organized by a very complex set of muscles,
which are in turn controlled by the body's local
and central nervous system
Stoma= mouth
Gnathion = jaws

5. The stomatognathic
system
= the masticatory
system
• Teeth
• Periodontium
• Jaws
• TMJ
• Associated muscles +
tongue & muscles of
the soft palate
• Investing tissues
• Neural control

6. The stomatognathic system
• There is a complex, dynamic
balance between the way that the
teeth come together, the muscle
that work the jaws, the joints, and
their relationship to the posture of the
head & neck. A change in any part of
the system affects all the others and
change the balance
The masticatory system

7. • When opposing teeth are in contact and
mandibular movements are made, the
direction of the movement is controlled
by the neuromuscular system as limited
by the movement
The stomatognathic system

8. NEURO MUSCULAR SYSTEM:
Muscles of Mastication:
Masseter
Temporalis
Lateral Pterygoid
Medial Pterygoid
Tempromandibular
Sphenomandibular
Stylomandibular
TMJ Capsule
Associated Ligaments

9. • The letters TMJ are short
for of 'temporo-mandibular
joint', which is the joint
connecting lower jaw and
the skull.
The movement in this joint lets you open and
close your mouth and chew from side to side.
Temporalis
Masseter

10. It has 4 anatomical parts:
1- Condyle
2- Articular fossa
3- Articular disc
4- Articular capsule
TMJ: is a bilateral joints permits the mandible
to move as a unit with two functional
patterns:
- Hinge (inferior portion)
- Translation (superior portion)

11.  Condyle: The rounded
articular surface at the
end of the mandible
(lower jaw).
 Glenoid fossa: A deep concavity in the temporal
bone at the root of the zygomatic arch that
receives the condyle of the mandible.
 Tubercle: A slight elevation from the surface of
the bone giving attachment to a muscle or
ligament.

12. Biconcave
articular
disc
C.T. capsule
• Dense fibrous connective tissue
• Lacks blood vessels and nerves
• Able to tolerate forces without damage or pain being
produced
• Provides protection to condyle and fossa during
movements

13. The Synovial fluid:
Consist of small amounts of a clear, straw-
colored viscous fluid. It is an infiltrate of the
blood diffused out from the rich capillary
network of the Synovial membrane.
Function:
1- Lubrication
2- Nutrition.
3- Clear the tissue debris.

14. TMJ LIGAMENTS AND CAPSULE
1-Collateral(discal)
2-Capsular
3-Tempromandibular
4-Sphenomandibular
5-Stylomandibular

15. Muscles of mastication
• There are four pairs of muscles
involved in mastication:
Prime movers, temporalis and
masseter
Grinding movements, medial
and lateral pterygoids and
buccinators

16. They are functionally classified as:
- Jaw elevators
 Masseter
 Temporalis
 Medial pterygoid
 Upper head of lateral pterygoid
- Jaw depressors
 Lower head of lateral pterygoid
 Anterior digastric
 Geniohyoid
 Mylohyoid

17. Masseter
• It has 3 layers
• Origin: border of the zygomatic arch
• Insertion: lateral surface of the ramus

18. Masseter
• Action:
• Elevation (deep fibers)
• Protraction (superficial fibers)
• Nerve supply:
• Anterior division of mandibular nerve (masseteric nerve)
• Blood supply:
• Transverse facial artery

19. Temporalis
Has 2 heads:
• Deep head (anterior, middle and posterior fibers)
• Superficial head (much smaller)

20. Temporalis
• Origin: Temporal fossa, Temporal fascia
• In an area bound by the inferior temporal
line above and the infra temporal crest
below
• Insertion:
• Coronoid process in its medial aspect
(apex, anterior and posterior border)
• Anterior border of the ramus.

21. Temporalis
• Action:
• Elevation (anterior fibers)
• Protraction (posterior fibers)
• Nerve supply:
• Anterior division of the mandibular nerve
(2 deep temporal nerves)

22. Lateral pterygoid
• Has 2 heads:
• Upper head:
• Origin: infratemporal surface & crest of the greater wing of
sphenoid
• Insertion: enters the TMJ & inserted into:
a) Pterygoid fovea of the neck of the mandible
b) Articular disc
c) capsule of TMJ (anterior aspect)

23. Lateral Pterygoid
Lower head:
• Origin: Lateral surface of the lateral
pterygoid plate
• Insertion: as upper head

24. Lateral Pterygoid
Action:
1. Both muscles produce depression of the
mandible.
2. Lat. & Med. pterygoid on 1 side protrude the
mandible to the opposite side.
3. Lat. & Med. pterygoid on the 2 sides cause
side to side movement

25. Lateral Pterygoid
• Nerve supply: Anterior division of mandibular
nerve (nerve to lateral Pterygoid)

26. Medial Pterygoid
Has 2 heads
Superficial head:
• Origin: a) maxillary tuberosity
b) neighboring part of palatine bone.
_ Insertion: Medial surface of the angle & ramus
below the mandibular foramen.

27. Medial Pterygoid (Sup. Head)

28. Medial Pterygoid
• Deep head:
Origin: Medial surface of the lateral pterygoid plate.
Insertion: as superficial head.
• Action: 1) both muscles elevate the mandible.
2 & 3 as in lateral pterygoid.
• Nerve supply: Trunk of the mandibular nerve
(nerve to medial pterygoid muscle)

29. Medial Pterygoid (Deep Head)

30. The Lat. Pterygo. advance the
condyles, thereby opening the mouth
(depressing the mandible), with the
assistance of the Digastric.
The oblique orientation of the
Masseters and Med. Pterygo. create
a sling. The non-working side Med.
Pterygo. contacts simultaneously
with the opposite side working
Masseter
normal reciprocal functioning of the Lateral Pterygoids
and Masseters/Med.Pteygoids/Temporalis

31. In normal chewing
function, the
mandible opens, and
then, while initiating
closing, there is a
shift slightly to the
side of the bolus, due
to the orientation of
the masseter and
medial pterygoid.

32. The combinded efforts of the Digastrics and
Lateral Pterygoids provide for natural jaw opening
Digastric muscles is not a muscle of
mastication but it play an important
role in mandibular function

33. Due to the orientation of the Lateral Pterygoids and the oblique
alignment of the condyles in relation to each other, contraction of
the Lat. Pt. initiates an instantaneous translation of the
condyles. The slope of the eminence provides for immediate
mandibular depression and disclusion of the teeth

37. • Contacts between
teeth
To occlude means to “close”.
• Occlusion is the act
or process of closure

38. • Assist in diagnosis
• To minimize failure
• Ensure predictable outcome
by minimizing loads on teeth

39. It is an important factor that
influences the stability of complete
dentures.

40. There are four main purposes
required for complete dentures

41. There are four properties required to
achieve these functions and purposes
• Support
• Retention
• Bracing
• Stability

42. Is the property of the
dentures, which causes them to
resist rotational movements
•Displacement during function
and parafunction.
•It is chiefly affected by the
various occlusions of the teeth

43. Is the Resistance of Denture to Tipping
(Rocking, torsional forces)
Tipping (Rocking)
Is the Rotation of
Denture around a
Fulcrum

44. Occlusion and
articulation are
important for
maintaining the
stability of complete
dentures

46. It is the STATIC relationship between the
incising or masticating teeth or tooth
analogues. “GPT 8”
It is an important factor that influences the
stability of complete dentures.

47. Static contact relationship that exist
after the jaw movement has stopped
and the tooth contact are identified

48. Occlusion is the closure of the
maxillary and mandibular teeth in centric
relation throughout the range of
functional and nonfunctional movements
of the mandible

49. The contact relationship between
the occlusal surfaces of teeth
during function
It is the DYNAMIC contacts relationship
of the teeth as the mandible moved to
and from eccentric relation.

50. The most retruded relation of the mandible to the
maxillae when the condyles are in the most
posterior unstrained position in the glenoid fossae
from which any movement can be made, (within
hinge movement).

51. This position is clinically discernible when the
condyle is directed superiorly and anteriorly
and restricted to a purely rotary movement
about a transverse horizontal axis.

52. Refers to the RELATIONSHIP of the
MANDIBLE TO THE SKULL as it rotates
around the ‘hinge-axis” before any
translatory movement of the condyles from their
“upper-most and mid-most position”.
It is irrespective of tooth position or
vertical dimension.

53. The relation of the mandible
to the maxillae when the
condyles are in the
uppermost and rearmost
position in the glenoid
fossae

54. Is the position of the
condyles in the glenoid
fossa where they are in a
stable non-muscle braced
position.

55. Dawson has defined this
position as the rearmost,
uppermost, midmost (RUM)
position of the condyle in the
fossa at which the medial pole
of the condyle disc assembly
is braced against the bony
wall of the eminentia.

56. In this position the condyles
are supported by the bony
structures and muscle
activity is balanced and
minimized (isometric
contraction)

57. Is the only constant repeatable,
reproducible, border position
within the functional limit to start
constructing a stable occlusion

58. Whatever is the definition of centric relation it is reproducible,
stable and functional position.
The rearmost, uppermost, midmost (RUM)
position of the condyle in the fossa
the most posterior unstrained position in
the glenoid fossae
in the uppermost and rearmost
position in the glenoid fossae
in the anterior-superior position
against the articular eminences

59. Centric Relation

60. Occlusion of teeth and mandibular
position
1.Ligamentous position:
• This is the extreme position to which
mandible can be displaced posteriorly.
• It is repeatable and reproducible.
• It is a point at the
intersection of the right
and left border positions
of the Gothic arch.

61. this position can be obtained
by interdigitation of upper
and lower teeth.
The maximum intercuspation
position alters with abrasion
and loss of the teeth as well
as periodontal disorders.
2.Tooth position (Maximum intercuspation):

62. Maximum
Intercuspation
The complete
intercuspation of
the opposing teeth
independent
of condylar position.
GPT8

63. CENTRIC
OCCLUSION
The occlusion of opposing teeth when the
mandible is in centric relation, This may or
may not coincide with the centric relation in
natural dentition GPT 8

64. • In 90% of individuals with full
complement of natural teeth, centric
occlusion (maximum intercuspation), does
not coincide with centric relation of the
jaws.
• In most patients centric occlusion is
located anterior to the centric relation
by 0.5-1.5 mm measured in the
horizontal plane.

65. Centric occlusion with
teeth present is a tooth
to tooth relation whereas
centric relation, is a
bone to bone relation
(Static positions)

66. Teeth fully
intercuspated
with the
condyles in
the RUM
position
The condyle in
the RUM
position. Due to
a conflict
between the
teeth and the
TMJ, only one
tooth can touch
its opposing
contact
The teeth in
conflict with the
optimal condylar
position. Full
intercuspation of
the teeth results in
an eccentric,
occlusally
determined
condylar position.

67. 3. Muscular position:
• It is the physiologic center of
the mandibular muscle balance
(center of muscular activity)
• It is normally coinciding with
tooth position.

68. Centric occlusion
Eccentric occlusion
An occlusion other than centric occlusion
Protrusive occlusion
Lateral occlusion

69. Excursive Movement
Movement occurring when mandible moves
away from maximum intercuspation
Balancing Interferences
Undesirable contacts occurring on
balancing side during lateral movements

70. No Translation

71. Translation

73. Posselt’s Figure

74. MP
MO
ICP
RCP
HA
MP = Maximal protrusion
ICP = Intercuspal position
RCP= Retruded Contact
position
HA = Hinge axis
MO = Maximum opening
EE=edge to edge
Posselt’s Figure
Habitual Arc of Closure

75. This relation exists when
the jaws are in centric
relation and the teeth
are in centric occlusion
(vertical)

76. Three - dimensional record,
Vertical relation,
Antero - posterior relation
and lateral relation,
i.e. to obtain a centric relation record
it is necessary first to determine the
vertical dimension of occlusion.

77. The closure of the mandible does not occur in a
straight upward movement but rather in a curve

78. In the edentulous patients, use the posterior
border position (centric relation) which is
within the functional range of movements.
For this reason, the relation of the mandible
to the maxilla should be recorded in the most
retruded position (C.R) and centric occlusion
made to coincide with it

79. Centric Occlusion made to
coincide with CR

80. • The distance measured between two points when
occluding members are in contact in centric
occlusion.
Vertical
Dimension Of Occlusion

81. VERTICAL
DIMENSION OF
OCCLUSION

82. Vertical
Dimension Of Occlusion
The degree of separation
between the maxillae and the
mandible when the teeth are in
centric occlusion.

83. Inter-alveolar Distance
Inter-ridge Distance
• The vertical distance
between specified
positions on the maxillary
and mandibular alveolar
ridges at the occlusal
vertical dimension.

84. The vertical dimension of the face when
the mandible is in rest position.
Vertical
Dimension Of Rest

85. Interocclusal distance
(Free way space)
• The space between the
maxillary and
mandibular occlusal
surfaces when the
mandible is in the rest
position.
when the mandible is in a specified
relaxed position, it ranges from 2-4 mm.

86. Supporting
Cusps
(centric cusps = Stamp Cusps )
The lingual cusps of the maxillary
posterior teeth and the buccal cusps
of the mandibular posterior teeth.

87. SUPPORTING CUSPS
From a coronal or frontal
view, the lingual cusps of
the upper teeth stamp into
the fossae of the lower teeth
and the buccal cusps of the
lower teeth stamp into the
fossae of the upper teeth.

88. Non-Centric Cusps
Noncentric Cusps –(Guiding Cusps)
the buccal cusps of the maxillary
posterior teeth and the lingual
cusps of the mandibular posterior
teeth.
Help to determine the path of the
supporting cusps during lateral and
protrusive movements.

89. SHEARING CUSPS
Shearing Cusps - another name
for non-centric cusps, so named
because they assist in the
shearing of food during
mastication

90. Canthus-Tragus line (arbitrary line)
Frankfort Plane
The interpupillary Line
The Ala-tragus Line
Ca.T
Ala. T
Fr. P
Occ.P
Int.L

91. Mandibular Lateral Translation
The translatory portion of lateral
excursions. This movement can occur in
an essentially pure translatory form in the
early part of the motion or in combination
with rotation in the latter part of the
motion, or both. It is described by three
components- amount, direction and
timing. Bennett movement.

92. Mandibular Lateral Translation
Immediate M.L.T. The
translatory portion of lateral
excursions in which the non-
working condyle moves
essentially straight medially as it
leaves centric relation. Dawson
argues against the existence of
Immediate M.L.T. in the absence
of frank pathology.
Progressive M.L.T. The translatory portion of lateral
excursions that occurs at a rate or amount directly
proportional to the forward movement of the non-working
condyle

93. Bennett Angel
• The angle formed by the
sagittal plane (assumed
straight protrusive path) and
the path of the non-working
(orbiting) condyle during
lateral mandibular movements
as viewed in the horizontal
plane.

94. Fisher Angel
• The angle formed
by the inclinations
of the protrusive
(orbiting) and
nonworking side
(rotating) condylar
paths as viewed in
the sagittal plane.

95. BALANCING SIDE.
CONDYLE HAS DOWNWARD
PATH.
Working side.
Condyle pivots.
Mandible &TMJ

96. • 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.

97. (Crossbite) - Malocclusion in
which the mandibular teeth are
located facial to an ideal occlusal
relationship with the opposing
maxillary teeth when all teeth are
maximally occluded.
Reverse Articulation