Cast partial denture or rpd

• Indication of RPD

  • Long span edentulous

• Distal/Terminal extension

• FPD is contraindicated that is youth under 17 yrs who have large pulp chambers lack of clinical crown length.

• Weak abutment teeth with poor periodontal support

•  need for cross arch stabilisation

• Excessive loss of residual alveolar ridge

•  Immediate teeth replacement.

Note: for multiple small edentulous spaces go for fpd than rpd.

Kennedy's classification

• CLASS I - Bilateral edentulous areas located posterior to remaining natural teeth (Bilateral Distal Extension) (Most Prevalent)

• CLASS II - Unilateral edentulous areas located posterior to the remaining natural teeth (Unilateral Distal Extension)

• CLASS III - Unilateral edentulous areas with natural teeth anterior & posterior to it

• CLASS IV - Single bilateral edentulous areas located anterior to remaining natural teeth which crosses the midline

Disadvantages  

• It does not tell about the periodontal status of the abutment

• It does not cover all the edentulous situations

• Extent of edentulous span is not known

Apple gate Rules

• Extraction should always preced the main classification 

• most posterior edentulous space decides the main classification 

• for modification always count no of spaces

• Kennedy's Class IV cannot have any modification

• 
  

Terms

• INTERIM PARTIAL DENTURE 

  • used for short period of time for aesthetic reasons, mastication or convenience until a more definitive form of tt  can be rendered .

• TRANSITIONAL PARTIAL DENTURE 

  • aids patient in making transition to a complete denture & Can be modified to accomodate additional loss of teeth. (Done for better pt adaptation)

• TREATMENT DENTURE

  • to establish new occlusal relationship and to condition the soft tissues that have be abused by ill fittings

  • eg Abused soft tissue

    • TISSUE CONDITIONER IS APPLIED → Act a  SHOCK ABSORBER

    • Heals abuse tissue

• Long term Collapse bite patient

  • series of Dentures is given to correct vertical height.

components of cast partial/removable partial denture

1. Major Connector

2. Minor connector

3. Rest - Vertical support

4. Direct retainer

5. Indirect retainer

6. Denture base

7. Artificial teeth replacement

Rest

• provides vertical support/stop

• prevents tissuewards movement

• Prevents impinchment of soft tissue during mastication.

Direct Retainer

• also C/d CLASP ASSEMBLY

• it provides RETENTION & prevents dislodgement of denture during mastication.

• Clasp tip engages the undercut

NOTE : Tooth-tissue support - Rotation is there - mechanism of rotation prevented by - FULCRUM SHIFT

• FULCRUM shift in RPD is achieved by Indirect Retainer.

• Hell Raising effect is prevented by indirect retainer 

  • Dent in DIstal extension cases

MAJOR CONNECTORS

• According to GPT-8, major connector is that part of a partial removable denture prosthetics that joins the components on one side of the arch to those on the opposite side.

• Resist flexing & torquing 

Requirements of major connector

1. it must be rigid then only other components will be effective

2. Must provide vertical support & protect the soft tissue.

   • If it is not rigit it will lead to stress- connection at the level of TEETH as well as at the level of RIDGE, leading to bone resorption around both of them.

3. Must provide means of obtaining indirect retention where indicated 

4. Must provide an opportunity of positioning denture based where needed.

5. Must maintain patient comfort 

6. Major connector should always be round off

Phonetics - Mainly affect by major connector 

major connector should be placed 3mm away from frees gingial margin in mandible away from gingival margin in maxilla.

Major connector should be parallel to free gingial margin

•  -Anterion-Posterior Palatal Strap (Close Horse-shoe), connector; A-P strap

• one of the most versatile maxillary major connector 

•  It is structurally strong & rigid

Indication

• It can be usde in almost all maxillary partial dentures deisg.

• It can be used in case of presence of torus palatines

U-Spahed major connector (Open horse shoe shaped)

Indication

• Inoperable large maxillary tori

• when replaceing multiple anterior teeth (kennedy clss IV)

NOTE : Derives support from anterior palate/ derive indirectly retention from palate (rugae area) UNDESIRABLE 

• it is strictly contraindicated in distal extension cases

• When forces are applied they flex laterally ( coz there is no bar +ent)

  • that is why it is leasted prefered maxillary major connector

Palatal Plate Connector

• Most rigid; most retentive; ma stability

Indication

• cleft Palate (1°)

• Multiple periodontally compromised teeth

• Kennedy's class I condition with severe resorption of residual ridges (b/z it provides stability & support by covering the soft tissues)

Advantages 

• Uniform thickness & anatomical replica of palate provided good comfort for patient & it does not disturb the speech 

• It provides good support & stability b/z of broad coverage 

• It also provides some amount of retention b/z of intimate contact

• It is a good choice for cleft palate cases

• It also acts as a traniner for complete denture therapy

• Used when there are natiral teeth in opposing mand arch

It beadinf-edges/periphery of connector are thickened & round 

• it is done to ensure intimate or positive contact 

• it prevents ingress of food beneath the denture 

• provides good finish lines for technician to finish 

Image 

Beading is done in maxillary major connector & contraindicated in mandibular major connector 

Mandibular Major connector

• Minimal support from residual ridges so ' indirect retention is needed to achieve stability

• less surface area for the major connector 

• Relief is frequently required from mandibular arch

• Beading is contra-indicated

Lingual Bar

• Lingual bar is the basic form of mandibular major connector 

• Half pear shaped 

• It requires minimum of 8 mm of lingual vestibular space (deep lingual sulcus)

Indication

• in all situation where indirect retention by major connector is not needed ( ie. tooth support ) & no stabilization of other weak teeh (class III)

• it has minimal contact with soft tissues

• First prference in slection of maj connectors

Sublingual bar

• Recommended to be used in shallow vestibules (less than 6mm of vestibular depth)

Lingual Plate ( Lingual Plate, Lingual Strap, Lingual apron, lingual shiled)

• Most versatile major in distal extension cases 

• it is  a type of major connector most commonly used in case of periodontally compromised remaining teeth (b/z it provides splinting effect to teeth)

Indications

• High frenal attachment (vestibule<8mm) shallow sulcus; highly active floor of mouth 

• presence of lingual tori (relief can be given)

• When indirect retention is needed ( in case of RRR)

• Stabilisation of ant periodontally weakened teeth

• When residual ridges in class I have undergone vertical resorption

• Long spaned ridges 

• Future replacement of one or more incisor teeth (b/z LP have provision of attachment)

Either it is lingual plate or its modification, it should be supported at each end by rest

Modification of lingual plate in case of diastema with distal extension ( STEP BACK DESIGN OF L.P.)

Double Lingual bar , Kennedy bar, Split bar, continuous lingual clasp

Modification of lingual plate

Indication

• it is indicated in case where the wide inter proxima areas prevent the use of lingual plate.

• Indicated primarily when some degree of indirect retention is required, pdl dz has resulted in large interproximal spaces ( black △)

• Horizontal Stablization 

Cingulum Bar 

 It a type of major connector which rests on the cingulum of anterior teeth.

Indicat" same as above, but still Kennedy's bar is used in case of indirect retent"& interproximal space is  +ent

Labial bar

t's a type of major Connector which is placed labial or buccal to alvedar ridge & teeth.

Indication

• It is indicated in case of lingually tilted ant. & post teeth

• Presence of large Lingual tori 

Disadvantage

• Esthetic poor

Swing-lock/hinged-continious labial bar

• Major connector is +ent lingually

• bar labially is not major connector (dimension is less) so less bulk (retention & stabilisation)

• Hinge at one end, locking at other

• Hinging action permits it to intimately placed against gingival tissue/undercut

• splinting action

Indication

• Too few remaning natural teeth for conventional denture

• Remaining teeth too mobile to srve as abutment for conventional RPD ( as when it will close then teeth wull work as single unit)

• position of remaining teeth not favourable for conventional RPD

• Retention & stabilisation needed for maxillofacial prosthesis eg obturators 

• to retain prosthesis who have lost large segments of ridge alveolar ridge through traumatic injury 

Minor Connectors

• According to GPT8, Minor connectors is the connecting link b/w the major connector or base of a partial removable dental prosthesis and the other units of the prosthesis, such as the clasp assembly, indrect retainers, occlusal rests, or cingulum rests

• Function

• Prosthesis to abutment function means which forces prosthesis to that abutment gets dissipated 

• Asosthesis to prosthesis function

• Rigid except Approach arm of I-bar.

• Forms right angle to major connector

• Abruptly crosses free gingival margin covering minumal gingival tissues.

• Only part of RPD that contacts guiding plate of abutment is MINOR CONNECTOR.

1. Joining the clasp assembly to the major connector.

2. Joining the indirect retainers or auxiliary rests

3. Joining the denture base to the major connector 

4. As approach arm for a vertical projection or bar type clasp.

Inconspicuous

Inter-proximal embrasure

• It should lie in embrasure b/w teeth disguise its bulk as much as possible

• Minor connector that joins to denture base to the major connector

3 types

• Lattice works cosntructions/loop & ladder design

• Mesh construction

• Bead, wire or nails head Minor connector

Open lattice work construction 

• In maxilla in covers ( till end of tuberosity ) whole ridge in mandible at junction of ant 2/3 post 1/3 present in framework not intray

• Tissue - it prevents distortion of the framework or distal extension framework during processing/packing

1. It provides strong attachment of the acrylic resin denture base to the RPD

2. In case of resorption of ridge 

   • RELINING CAN BE DONE 

3. Main Indication is (EASIEST TO RELINE) Distal extension case , Class III

   • Where multiple teeth need to be replaced 

   • made by 12 gauge half round & 18 gauge round 

Mesh Construction

• Mainly used for tooth supported situation

•  Main drawback is that it is more difficult to pack acrylic resin dough b/z more pressure is needed against the resin to force it through small holes

• It also does not provide as strong attachment for acrylic denture base as compared to lattice framework

• Difficult to reline.

 Bred, wire or mail head minor connector (Most Hygienic)

• Mainly used in class III cases 

• Retention of acrylic resin is obtained by projection of metal on its surface.

• Indicated when inter-arch space is limited ie in case of sup teeth

Disadvantage 

• Difficult to adjust the metal base

• weakest attachment with acrylic denture base

• Cannot be reline in case of ridge resorption

  • B/z of its metal framework