CLASP RETAINED REMOVABLE PARTIAL DENTURES by cuiliqing

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									  CLASP RETAINED
REMOVABLE PARTIAL
    DENTURES
    COMPONENT PARTS OF A
 REMOVABLE PARTIAL DENTURE

• Retentive Arm           •   Grid Retention Areas
• Bracing or Reciprocal   •   Tissue Stop
  Arm or Plate            •   Indirect Retainer
• Rest                    •   Denture Base
• Minor Connector         •   Denture Teeth
• Major Connector
          Cast RPD Framework
              Components
•   Major Connector
•   Minor Connectors
•   Clasp Assembly
•   Retention for Replacement Teeth
      Cast RPD Framework
          Components
• MAJOR CONNECTOR
• A major connector is the part of a RPD
  that connects the components on one side of
  the arch to the components on the opposite
  of the arch.
Major Connector Requirements

•   Rigidity
•   Should be contoured
•   Should avoid circumjacent structures
•   Minimum bulk
     Maxillary Major Connectors
•   Palatal Strap
•   Anterior Posterior (A-P) Palatal Strap
•   Palatal Plate
•   Palatal Bar
•   U-Shaped (Horseshoe) Palatal Connector
Palatal Strap
Palatal Strap
A-P Bar
• Palatal bar is defined as being 8mm or less
  in width.
• A palatal strap is greater than 8mm in width
• OBVIOUSLY,THIS IS NOT

           BRAIN SURGERY
Palatal Plate
     Strap or Bar ?
 Anterior edge should
follow contour of rugae
A-P Strap or Bars ????
Maxillary framework should be
6mm from free marginal
gingiva, if this is not possible
than the framework should end
on teeth.
     Maxillary Major Connectors
•   Palatal Strap
•   Anterior Posterior (A-P) Palatal Strap
•   Anterior Posterior (A-P) Palatal Bar
•   Palatal Plate
•   Palatal Bar
•   U-Shaped (Horseshoe) Palatal Connector
Mandibular Major Connectors
Mandibular Major Connectors

•   Lingual Bar
•   Lingual Plate
•   Double Ling Bar (Kennedy Bar)
•   Labial Bar
•   Swinglock
 Mandibular Major Connectors




Lingual Plate       Lingual Bar
• The superior border of a lingual bar should
  be at LEAST 4 mm below the free marginal
  gingiva.
Lingual Bar
   and
Lingual Plate
Indications For Use Of A Lingual
              Plate
• For stabilization of periodontally involved teeth.
• In Class I situations in which residual ridges have
  undergone excessive vertical resorption.
• When the lingual frenum is high or the space available
  between the gingival margin and the floor of the mouth is
  <8 mm.
• Lingual bar approximately 4mm + 4mm clearance from
  free marginal gingiva = 8mm and want no impingement of
  lingual frenum.
  Indications for use of a Lingual
          Plate, continued

• When the patient has found a lingual bar
  objectionable in the past
• When the future replacement of one or more
  incisor teeth will be facilitated by the
  addition to the lingual plate.
Lingual plates must always
terminate in a prepared rest seat
and never on an inclined surface.
Labial Bar
Double Lingual
     Bar
     or
 Kennedy Bar
Palatal torus




                U Shaped
Swing Lock
Major Connector
      Or
   Clasp???
Mandibular Major Connectors

•   Lingual Bar
•   Lingual Plate
•   Double Ling Bar (Kennedy Bar)
•   Labial Bar
•   Swinglock
      Cast RPD Framework
          Components
• MAJOR CONNECTOR
• MINOR CONNECTORS
• Minor connectors are those components
  that serve as the connecting link between
  the major connector and the other
  components.
• Many times a minor connector will be
  continuous with a lingual or palatal plate
  rather than a distinct element.
                Reciprocal Arm




Retentive Arm
APPLICATION OF CLASP
 ASSEMBLY TO TOOTH
• Minor connectors may play a critical role
  by serving as a connector for indirect
  retainers that minimize the rotation of free
  end saddles.
• An indirect retainer is that part of an RPD
  that assists the direct retainer in preventing
  displacement of distal extension denture
  bases by resisting lever action from the
  opposite side of the fulcrum line. It is the
  rest within the rest seat that prevents the
  displacement.
Indirect retention
• The ideal position for an indirect retainer is
  at a right angle to the fulcrum and located
  on the strongest tooth.
      Cast RPD Framework
          Components
• MAJOR CONNECTOR
• MINOR CONNECTORS
        Cast RPD Framework
            Components
• Major Connector
• Minor Connectors
• Clasp Assembly
• A clasp assembly is the part of a RPD that
  acts as a direct retainer and/or stabilizer for
  a prosthesis by partially encompassing or
  contacting an abutment tooth.
• Clasps are made up of a retentive arm, a
  reciprocal or bracing arm, and a rest.
CLASP ASSEMBLY
                       Clasp

•   Retentive Arm
•   Bracing or Reciprocal Arm or Plate
•   Rest
•   Minor Connector
                  Clasps
• Retentive Arm (Direct Retainer)-that
  component of an RPD used to retain or
  prevent dislodgement. The terminal third of
  which is the ONLY portion of the casting
  that touches the tooth BELOW the height
  of contour therefore, it must move over the
  height of contour for the RPD to go to
  place. It must flex or the tooth move.
                  Clasps
• Reciprocal Arm-stabilizes the tooth by
  being in contact with the opposing side of
  the tooth during the entire period of the
  retentive arm deformation. (Its movement
  over the height of contour during insertion
  and removal.)
          2o Bracing:
BRACING      – Cross arch bracing
                • location of retentive
                  arms on the same side
                  of the teeth on opposite
                  sides of the arch.
      RETENTION (pp84-93)
• Angle of convergence-THE UNDERCUT
              Size and Distance
• Length of the clasp arm
• Diameter of the clasp arm
• Cross sectional form of clasp arm
• Material used for clasp arm-CrCo vs Gold
• Uniformity of retention-across the arch
           Dental Retainers
•Clasps
  –Cast
      •Suprabulge
      •Infrabulge
  –Wrought wire
•Attachments
      •Intracoronal
      •Extracoronal
 Stress breaking
• Aim - reduce torquing force on distal
  abutment teeth
      Stress breaking
Mesial Rest - Wrought Wire
  RPI
REST
 PLATE
I-BAR
• Don’t get hung up on
  names of clasps; learn the
  principles, the names will
  change.
MADDEN CLASP
 Failure to
 cover the
retromolar
    pad

								
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