This lecture is about the Component Parts of Removable Partial Denture. I have a bit different classification of parts which makes it easy to understand and remember.
To listen to this lecture on youtube, browse through the playlist
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Feel free to ask questions.
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Connectors: Connect the different parts of RPD.
Major Connector: Connects the parts of prosthesis located on the one
side of the arch with the other side.
TYPES OF MAJOR CONNECTOR
- Plate
(max coverage area)
- Strap
(8mm+)
- Bar
(4mm)
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MAJOR CONNECTOR: Connects the parts of prosthesis
located on the one side of the arch with the other side.
FUNCTIONS
- Unification of major parts
- Distribution of applied forces
- Minimization of torque
- Cross arch stabilization
REQUIREMENTS
- In Max., 6mm away from gingiva
- In Man., 3mm away from gingiva
- Border should be parallel to the
gingival margin
- Adequate rests to be provided to
prevent the lateral and horizontal
forces
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MAJOR CONNECTOR: Connects the parts of prosthesis
located on the one side of the arch with the other side.
MAX. MAJOR CONNECT. TYPES
- Single palatal bar
- Single palatal plate
- Antero-posterior palatal bar
- Antero-posterior palatal strap
- Palatal plate-type
- U-shaped connector
MAN. MAJOR CONNECT. TYPES
- Lingual bar
- Linguoplate
- Sublingual bar
- Double lingual bar
- Cingulum bar
- Labial bar
- Swing-lock design
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Connectors: Connect the different parts of RPD.
Minor Connector: Connecting link between the major connector and
other units of prosthesis like clasp assembly, indirect retainer and rests.
TYPES OF MINOR CONNECTOR
The connector which connects/joins
- Direct retainer to major connector
- Indirect retainer to major connector
- Denture base to major connector
- Acts as approach arm in bar-type
clasp
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MINOR CONNECTOR: Connecting link between the major
connector and other units of prosthesis like clasp assembly,
indirect retainer and rests.
FUNCTIONS
- Connects the major connector
with other parts
- Transfers the stresses to
prosthesis
- Transfers forces to abutments
and edentulous ridge
IDEAL REQUIREMENTS
- Should be positioned in embrasure
area
- At least 5mm space between two
minor connectors
- Should provide space for
arrangement teeth
- Should facilitate the path of
placement
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Retainers: The part of PRD which is/may used for fixation,
stabilization or retention.
Direct Retainer: resists the dislodgement of the denture away from the
residual ridge in vertical dimension. Common source of retention are ‘clasps’.
TYPES OF DIRECTOR RETAINERS
1. Extracoronal (engage external
contour of an abutment)
- Retentive clasp arms
- Attachments
2. Intracoronal (resides within the
normal contours of an abutment)
- Precision attachments
- Semiprecision attachments
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DIRECT RETAINER: resists the dislodgement of the denture
away from the residual ridge in vertical dimension.
PRINCIPLE OF CLASP ASEMBLY
- Retention
- Support
- Stability
- Reciprocation
- Encirclement
- Passivity
CLASP PARTS
- Retentive arm
- Reciprocal arm
- Rest
- Body
- Minor connector
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DIRECT RETAINER: resists the dislodgement of the denture
away from the residual ridge in vertical dimension.
Clasps are of two types
OCCLUSAL APPROACHING |
CIRCUMFERENTIAL CLASP
• Simple circlet clasp
• Reverse circlet clasp
• Multiple circlet clasp
• Embrasure clasp
• Ring clasp
• Fishhook or hairpin clasp
• Onlay clasp
• Half and Half clasp
• Back action clasp
• Combination clasp
GINGIVAL APPROACHING | BAR
CLASP
• T clasp
• Modified T clasp
• Y clasp
• I clasp
- RPI System
- PRA System
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Retainers: The part of PRD which is/may used
for fixation, stabilization or retention.
INDIRECT RETAINER: assist the direct retainer in preventing the
displacement (of distal extension) of denture base by functioning
through lever action on opposite side of fulcrum line.
FORMS OF INDIRECT RETAINERS
- Rests (Occlusal, Cingulum,
Canine)
- Bars (Cingulum, Lingual)
- Linguoplate
- Rugae support
- Modification areas
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INDIRECT RETAINER: assist the direct retainer in preventing the
displacement (of distal extension) of denture base by functioning
through lever action on opposite side of fulcrum line.
FUNCTIONS
- Activates the direct retainer to
prevent the movement of a
distal extension
- Reduces the antero-posterior
tilting leverage on the
abutments
- Contact of its minor connector
with the axial tooth surface
helps in providing stabilization
against horizontal movement
- Anterior teeth supporting
indirect retainers are stabilized
against lingual movement
FUNCTIONS
- May act as auxiliary rest to support
a portion of the major connector,
facilitating the stress distribution
- Helps in accurate repositioning of
the prosthesis during relining or
rebasing
- Aids in additional support and
stability
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INDIRECT RETAINER: assist the direct retainer in preventing the
displacement of distal extension of denture base by functioning
through lever action on opposite side of fulcrum line.
EFFECTIVENESS OF INDIRECT
RETAINER
- Seating of occlusal rests in
movement
- Distance and location from
fulcrum line
- Rigidity
- Supporting tooth effectiveness
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Support: resistance to the movement towards the tissues.
Rigid Support: component (rest) of RPD lying on the tooth (rigid) surface
that provides the vertical support to the prosthesis.
FUNCTION
- Provides the vertical support and
transmits forces to abutments
- Resists the tissue-ward
movement of denture
- Maintains the components of
RPD in their planned positions
- Distributes and directs occlusal
loads to the abutments
- Directs the forces along the long
axis of the tooth
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Rigid Support: component (rest) of RPD lying on the tooth
(rigid) surface that provides the vertical support to the
prosthesis.
REST TYPES
- Occlusal rest
- Cingulum rest (canine and
incisor)
- Incisal rest
REST REQUIRMENTS
- Enamel should be sound
- Rest is supposed to be 2.5mm
deep
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Support: resistance to the movement towards the tissues.
Resilient Support (Distal Extension): support obtained by
bone/tissues.
FACTORS EFFECTING THE SUPPORT
- Contour & Quality of residual
ridge
- Extent of residual ridge coverage
by the denture base
- Type & accuracy of impression
registration
- Accuracy of the fit of denture
base
- Design of RPD framework
- Total occlusal load applied
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Denture Base: the part which rests on the
saddle area and carries the artificial teeth.
Conventional Denture Base: denture flanges are fully extended into
the sulcus areas to cover maximum available area.
FUNCTION
Artificial teeth used on a denture
transfer the occlusal forces to the
denture base and subsequently to
the natural teeth and edentulous
ridge.
Denture base provide the
retention, stability and support.
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Denture Base: the part which rests on the
saddle area and carries the artificial teeth.
Modified Denture Base: where conventional extended flanges are not
suitable. Gum-fit is most common.
INDICATIONS
- Aesthetics
- Deep undercuts
- Proclined premaxilla
- Bulging (labial segment or
tuberosity)
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IDEAL REQUIRMENTS
- Should be rigid
- Should provide vertical support
- Should protect tissues and not
the impinge them
- Should be compatible with
tissues
- Should be comfortable to
patient
- Easily cleanable
- Metal/alloy should be allergy free
- Should not allow food
accommodation
- Should not alter natural contour
- Should be inconspicuous (as
possible)
- Should cover as little tissues as
possible
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Assessment
Diagnostic casts are made. Initial
survey is done. Mouth preparations
done accordingly. Final models made.
Survey/Design
Final survey is done. RPD parts are
designed. Refractory casts are made
and design is transferred on it.
Wax-up
All the parts are waxed-up according
the design. Pattern is invested
Metal Process
Metal casting done. Metal frame is
finished and polished.
Trail(s)
Fame is trialed (tested) for proper
fitting. Teeth trail also done (if
needed).
Final Process/Insertion
Acrylic/teeth processed. Prothesis
finished and polished. Inserted.
Adjustments done afterwards as per
need.
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01 02 03
IMRAN FARRUKH
Principal, Professor
Dept. of Prostho.,
UMDC, University of
Faisalabad, Pakistan
MUHAMMAD BILAL
Assistant Professor
Dept. of Prostho.,
UMDC, University of
Faisalabad, Pakistan
SABA & MADIHA
Demonstrator
Dept. of Prostho.,
UMDC, University of
Faisalabad, Pakistan
04
INAM & Masood
Lab Professional
Dept. of Prostho.,
UMDC, University of
Faisalabad, Pakistan