3. 1. Define a major connector.
2. Describe its functions and location.
3. Explain the Mandibular major
connectors.
4. Explain the Maxillary major connectors.
5. Describe how to bead a maxillary cast.
4. Components of a RPD
1. Major connectors
2. Minor connectors
3. Rests
4. Direct retainers
5. Indirect retainers
(CLASS I AND CLASS II ONLY)
6. Denture bases
7. Teeth
5.
6. Major connector: the part of a partial
removable dental prosthesis that
joins the components on one side of
the arch to those on the opposite
side.
Major
7. It is that unit of the partial
denture to which all other parts
are directly or indirectly attached.
8. Functions
Joining of the major parts of the
prosthesis.
Distribution of the applied force
throughout the arch to selected
teeth and tissue.
Minimization of torque (a force that
tends to cause rotation) to the teeth.
9. A properly designed rigid major
connector effectively distributes
forces throughout the arch and acts
to reduce the load to any one area
while controlling prosthesis
movement.
10. The major connector may be
compared with the frame of a car or
with the foundation of a building.
It is through the major connector
that other components of the partial
denture become unified and be
effective.
11. If the major connector is flexible,
the ineffectiveness of connected
components dangers the
supporting oral structures and
can be a harm to the patient.
12. Failure of the major connector to
provide rigidity may be cause:
traumatic damage to periodontal
support of the abutment teeth,
injury to residual ridges, or
impingement of underlying tissue.
13.
14.
15.
16. Location
Major connectors should be designed
and located with the following
guidelines in mind:
1. Major connectors should
be free of movable tissue.
2. Impingement of gingival
tissue should be avoided.
17. Lingual bar major connector should
be located at least 3-4 mm inferior
to gingival margins
3-4 mm
18. 6 mm
Palatal major connector should be
located at least 6 mm away from
gingival margins.
19.
20. 3. Bony and soft tissue prominences
should be avoided during placement
and removal.
21. 4. Relief should be provided
beneath a major connector such
as inoperable tori or elevated
median palatal sutures.
22. 5. Major connectors should be
located and/or relieved to prevent
impingement of tissue that occurs
because the distal extension
denture rotates in function.
Relief
23.
24.
25.
26. Mandibular major connectors
The six types of mandibular major
connectors are:
1. Lingual bar
2. Linguoplate
3. Sublingual bar
4. Lingual bar with cingulum bar
5. Cingulum bar (continuous bar)
6. Labial bar
30. The lingual bar should be used for
mandibular removable partial dentures
when sufficient space exists between the
slightly elevated alveolar lingual sulcus
and the lingual gingival tissue.
31. Availability of space is a key factor in
determining whether a lingual bar can be
used. To accommodate a lingual bar, at
least 8 mm of vertical space must be
present between the gingival margins of
the teeth and the floor of the mouth.
32. Floor of the mouth
Record values in chart, transfer to cast
33. This permits the major connector
to have a minimum height of 5
mm and allows 3 mm of space
between the gingival margins and
the superior border of the bar.
34. When viewed in cross section,
a lingual bar is halfpear
shaped. The broadest portion
of the bar is located at its
inferior border, nearest the
floor of the mouth.
35. The presence of mandibular tori
complicates the design, fabrication,
and placement of lingual bar.
36. Advantages of the
lingual bar
Simple design
A lingual bar has minimal contact
with the remaining teeth and soft
tissues. So, there is decreased
plaque accumulation and
increased soft tissue stimulation.
37. Disadvantages of the
lingual bar
The greatest disadvantage is that
if care is not taken in the design
and construction of a lingual bar,
the framework may not be rigid.
This allows the concentration of
destructive forces upon teeth and
parts of the mandibular arch.
39. The structure of a lingual plate is that of
a half-pear-shaped lingual bar with a
thin, solid piece of metal extending from
its superior border. This thin projection
of metal is carried onto the lingual
surfaces of the teeth.
40. The inferior border of a lingual plate
should be positioned as low in the
floor of the mouth as possible, but
should not interfere with the
functional movements of the tongue
and soft tissues.
41. The superior border of a lingual plate
must be contoured to closely contact
the lingual surfaces of the teeth
above the cingulum.
42. It is important to note that lingual
plate must always be supported
by rests located no farther
posterior than the mesial fossae
of the first premolars.
43. Failure to provide these rests may
result in pronounced rotation of
the framework and labial
displacement of the remaining
anterior teeth. Terminal rests
45. Indications
1. It may be used because there is
less vertical space for a lingual bar.
This lack of space may be related to
gingival recession, high muscle
attachments, or high frenum
attachments on the lingual aspect of
the mandibular arch.
46.
47. 2. In those instances in which the
residual ridges in Class I arch have
undergone such vertical resorption
that they will offer only minimal
resistance to horizontal rotations of the
denture bases.
48. 3. A lingual plate also may be
indicated when the remaining teeth
have lost much of their periodontal
support and require splinting.
49. 4. When one or more anterior teeth
are periodontally compromised but
may provide service for a time, these
teeth may be supported by a lingual
plate until extraction is necessary.
50. 5. Lingual plate major connectors
also may be indicated for patients
with conditions that prevent the
removal of existing mandibular tori.
51. Advantages of the lingual
plate
One of the greatest advantages of
the lingual plate major connector
is its excellent rigidity.
Also, patients often consider a
well-fitting lingual plate more
comfortable than a lingual bar.
52. Disadvantages of the lingual
plate
The lingual plate's extensive
coverage may contribute to
decalcification of enamel surfaces
and irritation of the soft tissues in
patients with poor oral hygiene.
56. A modification of the lingual bar is
useful when the height of the floor of
the mouth does not allow placement
of the lingual bar at least 4 mm
below the free gingival margin is the
sublingual bar.
57. The bar shape remains the same as
that of a lingual bar, but placement is
inferior to the usual placement of a
lingual bar, lying over and parallel to
the anterior floor of the mouth.
58. Indications
The sublingual bar should be used
for mandibular removable partial
dentures when the height of the floor
of the mouth in relation to the free
gingival margins will be less than 6
mm.
59. Contraindications
Remaining natural anterior teeth
severely tilted towards the lingual.
Interfering lingual tori
High attachment of a lingual frenum
Interference with elevation of the
floor of the mouth during functional
movements.
61. A double lingual bar has
characteristics of both lingual bar
and lingual plate major connectors.
62. Unlike those of a lingual plate, however,
the upper and lower components of a
double lingual bar are not joined by a
continuous sheet of metal. As a result,
the lingual surfaces of the teeth and the
interproximal soft tissues are largely
exposed.
63. The two bars should be joined by rigid
minor connectors at each end. The
minor connectors should be located in
the interproximal spaces to hide the
thickness of the metal and to be less
noticeable to the tongue.
64. When wide diastema exist between
mandibular anterior teeth and a
linguoplate would objectionably
display metal.
Indications
67. A cingulum bar located on or
slightly above the cingulum of the
anterior teeth may be added to
the lingual bar or can be used
independently.
68. Indications
When a lingual plate or sublingual
bar is otherwise indicated but the
axial alignment of the anterior teeth
is such that excessive block-out of
interproximal undercuts would be
required.
69. Contraindications
1. Anterior teeth severely tilted to
the lingual.
2. When wide diastema that exist
between the mandibular anterior
teeth and the cingulum bar would
objectionably display metal in a
frontal view.
71. A labial bar runs across the
mucosa on the facial surface
of the mandibular arch.
72. Indications
1. Malpositioned or lingually
inclined teeth and
2. Large mandibular tori that
prevent the use of a lingual bar or
lingual plate.
73.
74. Swing-Lock removable partial
denture
It is a modification of the labial bar.
The modified labial bar has a hinge
at one end and a locking device at
the opposite end.
75. This permits an opening and closing
action similar to a gate.
The framework may be positioned in
the mouth with the gate in the open
position.
76. Upon complete seating of the
prosthesis, the gate may be closed.
This permits the RPD to reach
inaccessible undercuts on the
labial surfaces of the teeth.
77. 1. Lingual bar
2. Sublingual bar
3. Cingulum bar (continuous bar)
4. Linguoplate
5. Lingual bar with cingulum bar
78. Maxillary major connectors
The six types of maxillary major
connectors are:
1. Single palatal strap
2. Combination anterior and posterior palatal
strap- type connector
3. Palatal plate-type connector
4. U-shaped palatal connector
5. Single palatal bar
6. Anterior–posterior palatal bars
80. Bilateral tooth-supported prostheses, are
connected with a single, broad palatal
strap connector, particularly when the
edentulous areas are located posteriorly.
Indications
81. The anteroposterior dimension of
a palatal strap major connector
should not be less than 8 mm to
avoid compromise of its rigidity.
82. A single palatal strap major
connector should not be used to
connect anterior replacements
with distal extension bases.
83. Since this configuration offers little
interference with normal tongue
action, palatal strap major
connectors are well accepted by
patients.
In addition, the increased tissue
coverage helps distribute applied
stresses over a larger area.
85. The anterior border of this strap
should be located just posterior to a
rugae crest or in the valley between
two crests.
86. The posterior strap is thin, a minimum of
8 mm wide, and located as far
posteriorly as possible, yet entirely on
the hard palate.
It should be located at right angles to
midline rather than diagonally.
87. 1. Class I and II arches.
2. Long edentulous spans in Class II,
modification 1 arches.
3. Class IV arches
4. Inoperable palatal tori that
do not extend posteriorly to
the junction of the hard
and soft palates.
Indications
88. The only condition that prevents
their use is an inoperable maxillary
torus that extends posterior to the
soft palate.
90. Palatal plate is a term used for
any thin, broad, contoured palatal
coverage used as a maxillary
major connector and covering one
half or more of the hard palate
91. Indications
1. Some or all anterior
teeth remain.
2. Class II arch with a large
posterior modification space and
some missing anterior teeth.
92. 3. Class I arch with one to
four premolars and some
or all anterior teeth remaining.
4. When abutment support is poor;
5. Residual ridges have undergone
resorption.
94. From both the patient’s standpoint
and a mechanical standpoint, the U-
shaped palatal connector is the
least desirable of maxillary major
connectors.
95. Its lack of rigidity can allow
lateral flexure under occlusal
forces, which may induce
torque or direct lateral force to
abutment teeth.
97. When a large inoperable palatal torus
exists, and occasionally when several
anterior teeth are to be replaced, the
U-shaped palatal connector may have
to be used.
Indications
99. The single palatal bar is perhaps
the most widely used and yet the
least logical of all palatal major
connectors.
100. A partial denture made with a single
palatal bar is often too thin and
flexible or too bulky and
objectionable to the patient’s tongue.
The decision to use a single palatal
bar instead of a strap should be
based on the size of the denture-
bearing areas that are connected.
102. This combination of major connectors
has many of the same disadvantages as
the single palatal bar. To be sufficiently
rigid and to provide needed support and
stability, these connectors could be too
bulky and could interfere with tongue
function.
103. The anteroposterior palatal bar
may be used when support is not
a major consideration and when
the anterior and posterior
abutments are widely separated.
Indications
104. Anteroposterior palatal bar
major connectors also may be
chosen for patients with large
palatal tori that cannot be
removed for health reasons.
105. Beading of the Maxillary Cast
Beading is a term used to denote the
scribing of a shallow groove on the
maxillary master cast outlining the
palatal major connector exclusive of
rugae areas.
106. A shallow groove of 0.5 mm
It is a slightly rounded groove
Beading is done with a cleoid carver/
spoon excavator
107. The purposes of beading are as
follows:
1. To transfer the major connector
design to the investment
(refractory) cast.
108. 2. To provide a visible finishing line for
the casting.
3. To ensure close tissue contact of
the major connector with selected
palatal tissue.
