Components of a Typical RPDComponents of a Typical RPD

Major connectorsMajor connectors Minor connectorsMinor connectors Direct retainersDirect retainers Indirect retainers (if Indirect retainers (if

the prosthesis has the prosthesis has distal extension bases)distal extension bases)

One or more bases, One or more bases, each supporting one to each supporting one to several replacement several replacement teeth teeth

(a)(a) Major Connector: Major Connector: The The Component of RPD that connects the parts of of RPD that connects the parts of

one side of the dental arch to those of the other side. one side of the dental arch to those of the other side. • Unit of partial denture to which All other parts are

directly or indirectly attached.

(b)(b) Minor Connector: Minor Connector: A unit of a partial denture that connects other A unit of a partial denture that connects other

components (i.e. direct retainer, indirect retainer, components (i.e. direct retainer, indirect retainer, denture base, etc.) to the major connector.denture base, etc.) to the major connector.

(c)(c) Direct Retainer: Direct Retainer: A unit of a partial denture that provides retention A unit of a partial denture that provides retention

against dislodging forces.against dislodging forces. A direct retainer is commonly called a 'clasp' or 'clasp A direct retainer is commonly called a 'clasp' or 'clasp

unit' and is composed of four elements, a rest, a unit' and is composed of four elements, a rest, a retentive arm, a reciprocal arm and a minor connector.retentive arm, a reciprocal arm and a minor connector.

(d)(d) Indirect Retainer: Indirect Retainer: A unit of a Class I or II partial denture that prevents or resists A unit of a Class I or II partial denture that prevents or resists

movement or rotation of the base(s) away from the residual ridge. movement or rotation of the base(s) away from the residual ridge. The indirect retainer is usually composed of one component, a The indirect retainer is usually composed of one component, a

rest.rest. It is functioned through lever action on the opposite side of It is functioned through lever action on the opposite side of

fulcrum line when denture moves away from tissuefulcrum line when denture moves away from tissue

(e) (e) Denture Base: Denture Base: The unit of a partial denture that covers the residual The unit of a partial denture that covers the residual

ridges and supports the denture teeth and transfer ridges and supports the denture teeth and transfer occlusal forces to the supporting oral structures.occlusal forces to the supporting oral structures.

(f) rests:(f) rests:Any unit of partial denture that rests on a tooth surface Any unit of partial denture that rests on a tooth surface to provide vertical support.to provide vertical support.

(g) Stabilizing or (g) Stabilizing or reciprocal components:reciprocal components:

When direct retainer comes When direct retainer comes into contact with abutment, into contact with abutment, the framework must be the framework must be stabilized against horizontal stabilized against horizontal movement for the required movement for the required clasp deformation to occur. clasp deformation to occur. Stabilization is derived from Stabilization is derived from either cross-arch framework either cross-arch framework contacts or stabilizing or contacts or stabilizing or reciprocal clasp in the same reciprocal clasp in the same clasp assemblyclasp assembly

Tissue stopperTissue stoppero Are integral parts of minor connectors designed for Are integral parts of minor connectors designed for

retention of acrylic resin bases.retention of acrylic resin bases.o They provide stability to framework during They provide stability to framework during

processing and prevent the possibility of the processing and prevent the possibility of the framework being pushed down ward as the acrylic framework being pushed down ward as the acrylic dough is packed into mold.dough is packed into mold.

o They are useful in preventing distortion of the They are useful in preventing distortion of the framework during acrylic resin processing framework during acrylic resin processing procedures.procedures.

o Tissue stops can engage buccal and lingual slopes Tissue stops can engage buccal and lingual slopes of residual ridge for stability.of residual ridge for stability.

MAXILLARY MAJOR

CONNECTORS

Major connectors( bars or plates)Major connectors( bars or plates)LocationLocation

1- free of movable tissue 1- free of movable tissue 2- avoid impingement of gingival tissue2- avoid impingement of gingival tissue3-avoid prominent bone and soft tissues3-avoid prominent bone and soft tissues4-relief under it ?4-relief under it ?5- They should be located and/or relieved to 5- They should be located and/or relieved to prevent impingement of tissue because the distal prevent impingement of tissue because the distal extension denture rotates in function.extension denture rotates in function.

Requirements of a Major ConnectorRequirements of a Major Connector

1- made from alloy compatible with oral 1- made from alloy compatible with oral tissuetissue

2- It is rigid and provides Cross-Arch 2- It is rigid and provides Cross-Arch Stabilization (Counter leverage)Stabilization (Counter leverage) Bracing elements on one side of the arch Bracing elements on one side of the arch

providing stability to the otherproviding stability to the other

3-Non-Interference With and is not 3-Non-Interference With and is not irritating to the Tissues(tongue).irritating to the Tissues(tongue).

4-does not alter the natural contour of lingual 4-does not alter the natural contour of lingual surface of mandible or palatal vault of surface of mandible or palatal vault of maxillamaxilla

5- does not impinge on oral tissue when 5- does not impinge on oral tissue when restoration is placed, removed, or rotates in restoration is placed, removed, or rotates in function.function.

6- covers no more tissue than is absolutely 6- covers no more tissue than is absolutely necessary.necessary.

7-Minimize Food Impaction7-Minimize Food Impaction Locate margins away from the FGMLocate margins away from the FGM Eliminate "traps" or large concavities Eliminate "traps" or large concavities

where food can collectwhere food can collect

8- support from other elements of the 8- support from other elements of the framework to minimize rotationframework to minimize rotation

9-support the prosthesis.9-support the prosthesis.

Beading:- Beading:- is scribing a shallow groove on maxillary master is scribing a shallow groove on maxillary master cast( when major connector exclusive to rugae areas) to:-cast( when major connector exclusive to rugae areas) to:-1- transfer the major connector design to the investment 1- transfer the major connector design to the investment castcast2-provide visible finishing line for the casting2-provide visible finishing line for the casting3- ensure intimate tissue contact of major connector with 3- ensure intimate tissue contact of major connector with selected palatal tissueselected palatal tissue

Maxillary Major ConnectorsMaxillary Major Connectors

single Palatal Strapsingle Palatal Strap Single palatal barSingle palatal bar Anterior-Posterior Palatal StrapAnterior-Posterior Palatal Strap Anterior-Posterior Palatal barAnterior-Posterior Palatal bar Palatal platePalatal plate U-shape palatal connectorU-shape palatal connector

Single Palatal Strap

• Used to connect bilateral tooth-supported prosthesis, even those with short edentulous spaces, particularly when the edentulous areas are located posteriorly.

Palatal StrapPalatal Strap It can be made rigid without objectionable bulk and interference with the tongue.It can be made rigid without objectionable bulk and interference with the tongue.

Thin and wide anterior-posteriorly.Thin and wide anterior-posteriorly.

Indication Indication •Class III or Class III modification I partially Class III or Class III modification I partially edentulous arch (short edentulous span).edentulous arch (short edentulous span). Contraindication :Contraindication :•Tooth-tissue supported partial dentures(Class I Tooth-tissue supported partial dentures(Class I and class II).and class II).•Presence of palatal torusPresence of palatal torus•Extremely long tooth supported edentulous space.Extremely long tooth supported edentulous space.

Palatal BarPalatal BarNarrow antero-posteriorlyNarrow antero-posteriorlyThick occluso-gingivally Thick occluso-gingivally Palatal bar objectionable due to bulk.Palatal bar objectionable due to bulk.

Single palatal barSingle palatal bar-Palatal connector less than 8mm in width-Palatal connector less than 8mm in width

-It must be rigid enough for cross- arch distribution, It must be rigid enough for cross- arch distribution, therefore:- it is therefore:- it is objectionable.objectionable.

-It is indicated in tooth borne unilateral or bilateral It is indicated in tooth borne unilateral or bilateral spaces spaces

Palatal Strap (or Bar)Palatal Strap (or Bar) NeverNever use in cases involving distal extensions or use in cases involving distal extensions or

replacement of anterior teeth since it must be replacement of anterior teeth since it must be made bulky for rigiditymade bulky for rigidity

Relief may be required over bony midline Relief may be required over bony midline Not used with torusNot used with torus

Combination Anterior and Posterior Palatal Strap-type

Connector• Structurally a rigid major connector.• May be used in any maxillary partial denture

design.

• Posterior palatal strap :Design- flat and minimum 8 mm wide.Location- as far posteriorly as possible to avoid

interference with tongue but anterior to line of flexure formed by the junction of hard and soft palates.

• Anterior connector : Location: extended anteriorly to support anterior tooth

replacements. Strength: lies in the fact that anterior and posterior

components are joined together by longitudinal connectors on either side, forming a square or rectangular frame. Each component braces the others against possible torque and flexure.

All maxillary major connectors should cross the midline at a right angle rather than

on a diagonal.

Indications1.Class III or Class III ,modification 1,Class II, modification 1 partially edentulous arch with long span edentulous space or spaces.

2. Class I and II arches in which excellent abutment and residual ridge support exists.

3. Class IV arches in which anterior teeth must be replaced with a removable partial denture.

4. In operable palatal tori.

.

Contraindication

•In inoperable maxillary torus that extends posteriorly to soft palate (a broad U-shaped major connector is used).

Anterior-Posterior Palatal BarAnterior-Posterior Palatal Bar A narrow (A-P) variation of anterior-A narrow (A-P) variation of anterior-

posterior palatal strap posterior palatal strap Double palatal bar connector Double palatal bar connector Requires greater bulk for rigidity Requires greater bulk for rigidity

Anterior-Posterior Palatal BarAnterior-Posterior Palatal Bar

More objectionable to the patient More objectionable to the patient Strap connectors provide greater Strap connectors provide greater

distribution of stressesdistribution of stresses It may be used in any partial denture It may be used in any partial denture

design.design.

Palatal Plate-type Connector• Thin, broad, contoured palatal coverage,

covering one half or more of the hard palate.• Anatomic replica palatal castings have uniform

thickness and strength because of their corrugated contours.

Palatal major connector covering two thirds of palate. Anterior border follows valleys between rugae and does not extend anterior to indirect retainers on first premolars. Posterior border is located at junction of hard and soft palates but does not extend onto soft palate.

• Anatomic replica palatal major connector has several advantages:

Permits making of a uniformly thin metal plate that reproduces the anatomic contours of the patient’s own palate.

The corrugation in the anatomic replica permits fabrication of a thinner casting with adequate rigidity.

Intentional surface irregularities maintain the original uniform thickness of the plastic pattern (only electrolytic polishing is needed).

By virtue of intimate contact, interfacial surface tension between metal and tissue provides the prosthesis with greater retention. (to resist the pull of sticky foods, the forces of gravity, coughing, sneezing etc

Uses of palatal plate-type connector • May be used in one of three ways :as a plate of varying width that covers the area

between two or more edentulous areas, as a complete or partial cast plate that extends posteriorly to the junction of hard and soft palates (figures A & B).

in the form of an anterior palatal connector with a provision for extending an acrylic resin denture base posteriorly (figures C & D).

INDICATIONS:INDICATIONS:

•In class I (with 1-4 )premolars and some of In class I (with 1-4 )premolars and some of anterior teeth remaining.anterior teeth remaining.

•Class II with large posterior modification space Class II with large posterior modification space and some missing anterior teeth.and some missing anterior teeth.

•Class I with the last remaining abutment tooth on Class I with the last remaining abutment tooth on either side is the canine or 1either side is the canine or 1stst premolar tooth. premolar tooth.

• Class III with poor condition of remaining Class III with poor condition of remaining anterior teeth.anterior teeth.

• Patient with cleft palate to close any air passage Patient with cleft palate to close any air passage between nasal and oral cavity.between nasal and oral cavity.

• Absence of palatal torus.Absence of palatal torus.

Anterior Palatal Plate Anterior Palatal Plate (U-Shaped or "Horse-Shoe" Palatal Connector)(U-Shaped or "Horse-Shoe" Palatal Connector)

Poor connector Poor connector NeverNever use unless absolutely necessary use unless absolutely necessary Requires bulk in the rugae area (where the tongue Requires bulk in the rugae area (where the tongue

requires freedom) for rigidityrequires freedom) for rigidity

Anterior Palatal Plate Anterior Palatal Plate

DisadvantagesDisadvantages•Lack of rigidityLack of rigidity•Fail to provide good support and thus permit Fail to provide good support and thus permit impingement of underlying tissue when subjected to impingement of underlying tissue when subjected to occlusal forcesocclusal forces•Bulk to enhance rigidity results in increased thickness Bulk to enhance rigidity results in increased thickness in areas are hindrance to the tonguein areas are hindrance to the tongue

indicationsindications1- large inoperable torus1- large inoperable torus2- several anterior teeth are to be 2- several anterior teeth are to be replacedreplaced

Mandibular Major ConnectorsMandibular Major Connectors

Lingual Bar most widely usedLingual Bar most widely used Lingual Plate Lingual Plate Sublingual BarSublingual Bar Continuous BarContinuous Bar Cingulum bar (continuous bar).Cingulum bar (continuous bar). Labial BarLabial Bar

• Relief is provided for soft tissue under all portions of mandibular major connector and any location where the framework crosses the gingival margin.

• The inferior border does not impinge on the tissue in the floor of the mouth during the normal activities.

• Located as far inferiorly as possible to avoid interference with the resting tongue and trapping of food substances

Methods to determine the relative height of the floor of the mouth:

1- Measure the height of the floor of the mouth in relation to the lingual gingival margins of adjacent teeth with a periodontal probe.

2-Use an impression material with an individualized impression tray having its lingual borders 3 mm short of the elevated floor of the mouth

Characteristics and location

o Half-pear shaped with bulkiest portion inferiorly located.

o Superior border tapered to soft tissue.

o Superior border located at least 4mm inferior to gingival margins.

o Inferior border located at the ascertained height of the alveolar

lingual sulcus when the patients tongue is slightly elevated

o The inferior border of the lingual bar should be slightly round

when the framework is polished.

Indications:Indications:1-sufficient space between slightly elevated alveolar lingual sulcus and lingual gingival tissue (9-1-sufficient space between slightly elevated alveolar lingual sulcus and lingual gingival tissue (9-11mm).11mm).2-2-sufficient sufficient indirect retention by clasp and indirect retainer.indirect retention by clasp and indirect retainer.3-Future additions of prosthetic teeth to the framework are not anticipated3-Future additions of prosthetic teeth to the framework are not anticipated4- diastema or opened cervical embrasures.4- diastema or opened cervical embrasures.5-over lapped anterior teeth5-over lapped anterior teeth

Mandibular Major ConnectorsMandibular Major Connectors ContraindicationsContraindications 1- space not enough(less than 8mm).1- space not enough(less than 8mm). 2- only few anterior teeth remain2- only few anterior teeth remain 3-lingually inclined teeth3-lingually inclined teeth 4-lingual undercut in alveolar ridge4-lingual undercut in alveolar ridge 5- parallel or sloped anterior lingual alveolar contour in 5- parallel or sloped anterior lingual alveolar contour in

a distal extension RPD because the bar may rotate into a distal extension RPD because the bar may rotate into tissue as denture base moves toward residual ridgetissue as denture base moves toward residual ridge

Lingual Plate (Linguoplate)Lingual Plate (Linguoplate)

Lingual bar with extension over cingula of Lingual bar with extension over cingula of anterior teethanterior teeth

Should have rest at each end regardless the Should have rest at each end regardless the need of indirect retainer.need of indirect retainer.

• The upper border should follow the natural curvature of the supracingular surfaces of the teeth.

• The half— pear shape of a lingual bar should still form the inferior border providing the greatest bulk and rigidity.

• All gingival crevices and deep embrasures must be blocked out parallel to the path of placement to avoid gingival irritation and any wedging effect between the teeth.

• The linguoplate does not in itself serve as an indirect retainer. When indirect retention is required, definite rests must be pr‹›vided for this purpose

Lingual Plate IndicationsLingual Plate Indications

floor of the mouth space is limitedfloor of the mouth space is limited Prominent lingual frenum Prominent lingual frenum Lingual tori can t removed surgicallyLingual tori can t removed surgically Stabilizing periodontally weakened teethStabilizing periodontally weakened teeth Futural replacement of one or more incisor teethFutural replacement of one or more incisor teeth Only few remaining anterior teethOnly few remaining anterior teeth

Lingual PlateLingual Plate Distal extension RPD with sloped lingual alveolar Distal extension RPD with sloped lingual alveolar

ridge.ridge. 8-8- Mandibular tori or exostosis. Relief is provided Mandibular tori or exostosis. Relief is provided

between the torus or exostosis and the framework.between the torus or exostosis and the framework.

Lingual Plate contraindicationsLingual Plate contraindications When lingual bar is usedWhen lingual bar is used Overlapped anterior teethOverlapped anterior teeth Lingually inclined teethLingually inclined teeth Diastema unless it has slots.( disadvantages)Diastema unless it has slots.( disadvantages) Open cervical embrasuresOpen cervical embrasures

Continuous Bar Retainer Continuous Bar Retainer Lingual bar with secondary bar above cingulaLingual bar with secondary bar above cingula Narrow 3mmmetal strapNarrow 3mmmetal strap Originated from incisal, lingual or occlusal Originated from incisal, lingual or occlusal

rests of adjacent abutmentsrests of adjacent abutments

Continuous Bar Retainer Continuous Bar Retainer

Excellent IR.Excellent IR.

indications:indications:1-lingual plate indicated but axial alignment 1-lingual plate indicated but axial alignment of anterior teeth require excessive block out of anterior teeth require excessive block out of interproximal undercuts.of interproximal undercuts.2-wide diastema2-wide diastema3-when major connector must contact 3-when major connector must contact natural teeth for bracing and IR with open natural teeth for bracing and IR with open cervical embrasures. cervical embrasures.

Contra indications:Contra indications:

1-Where a lingual bar or lingual plate will suffice.1-Where a lingual bar or lingual plate will suffice.

2-Any contra indicatiDn for a lingual bar.2-Any contra indicatiDn for a lingual bar.

3-Any contra indication for a lingual3-Any contra indication for a lingual plateplate except except open open cervical embrasures.cervical embrasures.

Sublingual barSublingual bar

Useful when the height of the floor of the Useful when the height of the floor of the mouth not allow placement of bar 4 mm mouth not allow placement of bar 4 mm below the FGMbelow the FGM

indications:indications:1- the height of floor of the mouth less than 6 mm1- the height of floor of the mouth less than 6 mm2- used when it is desirable to keep FGM exposed 2- used when it is desirable to keep FGM exposed and there is inadequate depth of floor of mouth to and there is inadequate depth of floor of mouth to place lingual bar.place lingual bar.3-presence of anterior lingual undercut3-presence of anterior lingual undercut4- bracing and IR can be provided4- bracing and IR can be provided5- distal extension with sloped lingual alveolar 5- distal extension with sloped lingual alveolar ridge ridge 6- diastema and opened cervical ebrasure.6- diastema and opened cervical ebrasure.7- over lapped anterior teeth7- over lapped anterior teeth8- intolerance to other types of major connectors8- intolerance to other types of major connectors

Contraindications:Contraindications:1-lingual bar or lingual plate is sufficient1-lingual bar or lingual plate is sufficient2-natural anterior teeth severely tilted 2-natural anterior teeth severely tilted lingually lingually 3-interfering tori3-interfering tori4-interferance with elevation of the floor of 4-interferance with elevation of the floor of the mouththe mouth5-future addition of teeth may be anticipated5-future addition of teeth may be anticipated

Indications:1-Axial alignment of the anterior teeth is such that the excessive block out of interproximal undercuts would be required.2-Lingual frenum and floor of the mouth at the same level as marginal gingiva.3-lnoperable tori or exostosis at the same level as the marginal gingiva.

4-Severely undercut lingual alveolus..5-Considerable gingival recession.

Contra indications:

1-Anterior teeth severely tilted to the lingual.

2-When wide diastemata exist between the mandibular anterior teeth .

Labial BarLabial Bar-Bar on labial or buccal sulcus -Bar on labial or buccal sulcus -Superior border located 4mm inferior to labial gingival margin.-Superior border located 4mm inferior to labial gingival margin.-Inferior border at the junction between attached and unattached Inferior border at the junction between attached and unattached mucosamucosa-It must be relieved in canine eminence areaIt must be relieved in canine eminence area

Labial barLabial barIndications:Indications:1.When the mandibular teeth are so severely 1.When the mandibular teeth are so severely

inclined lingually as to prevent the use of inclined lingually as to prevent the use of lingual major connector.lingual major connector.

2.When large lingual tori exist and their removal is 2.When large lingual tori exist and their removal is contraindicated.contraindicated.

3-abnormal high lingual frenum3-abnormal high lingual frenum4-severe lingual tissue undercuts.4-severe lingual tissue undercuts.5- patient cant tolerate lingual bar.5- patient cant tolerate lingual bar.

contraindicationscontraindications1- when lingual major connector may be used.1- when lingual major connector may be used.2-labial tori2-labial tori3-facial alveolar ridge has undercut3-facial alveolar ridge has undercut4-high facial muscle attachment result in less 4-high facial muscle attachment result in less

than 4 mm of space between superior edge than 4 mm of space between superior edge of labial bar and marginal gingiva of the of labial bar and marginal gingiva of the teethteeth

A modification to the linguoplate is the hinged continuous labial bar. consists of a labial or buccal bar that is connected to the major connector by a hinge on one end and a latch at the other end.

• Support is provided by multiple rests on the remaining natural teeth.

• Stabilization and reciprocation are provided by a linguoplate contacting the remaining teeth and are supplemented by the labial bar with its retentive struts.

• Retention is provided by a bar type of retentive clasp arms projecting from the labial or buccal bar and contacting the infrabulge areas on the labial surfaces of the teeth.

Indications:1- Missing key abutments (such as canine).2- Unfavorable tooth contours. 3- Unfavorable soft tissue contours..4- Teeth with questionable prognoses

Contra indications:1-Poor oral hygiene and lack of patient motivation. 2-Shallow buccal or labial vestibule.3-High frenal attachment (labial or buccal frenum).