Introduction to Removable Partial Prosthodontics

Introduction to Removable Introduction to Removable Partial ProsthodonticsPartial Prosthodontics

Rola M. Shadid, BDS, MScRola M. Shadid, BDS, MSc

Partial DenturePartial Denture

A prosthesis that replaces A prosthesis that replaces one or more, but not one or more, but not all of the natural teeth all of the natural teeth and supporting and supporting structures. It is structures. It is supported by the teeth supported by the teeth and/or the mucosa. It and/or the mucosa. It may be fixed (i.e. a may be fixed (i.e. a bridge) or removable.bridge) or removable.

Removable Partial Denture (RPD)Removable Partial Denture (RPD)

A partial denture that can be removed and A partial denture that can be removed and replaced in the mouth by the patient.replaced in the mouth by the patient.

Can be interim RPD (all-resin) or definitive Can be interim RPD (all-resin) or definitive cast framework RPDcast framework RPD

Interim Rmovable Partial Denture Interim Rmovable Partial Denture (Provisional; Temporary)(Provisional; Temporary)

A denture used for a A denture used for a short interval of time short interval of time to provide:to provide:

a. a. esthetics, mastication, esthetics, mastication, occlusal support and occlusal support and convenience.convenience.

b. b. conditioning of the conditioning of the patient to accept the patient to accept the final prosthesis.final prosthesis.

Retention:Retention:

Resistance to removal from the tissues or teethResistance to removal from the tissues or teeth

Stability:Stability:

Resistance to movement in a horizontal Resistance to movement in a horizontal direction (anterior-posteriorly or medio-direction (anterior-posteriorly or medio-laterallylaterally

Support:Support:

Resistance to movement towards the tissues Resistance to movement towards the tissues or teethor teeth

Abutment:Abutment: A tooth A tooth that supports a partial that supports a partial denture.denture.

Retainer:Retainer: A component A component of a partial denture of a partial denture that provides both that provides both retention and support retention and support for the partial denturefor the partial denture

Classification of Classification of Partially Edentulous Partially Edentulous

ArchesArches

Major Categories of Partial Tooth Major Categories of Partial Tooth LossLoss

Tooth- and tissue-Tooth- and tissue-supported spacesupported space

Tooth-supported Tooth-supported

spacespace

Requirements of an Acceptable Requirements of an Acceptable Classification…..Classification…..

should permit immediate visualization of should permit immediate visualization of the type of partially edentulous arch that the type of partially edentulous arch that is being considered.is being considered.

should permit immediate differentiation should permit immediate differentiation between the tooth-supported and the between the tooth-supported and the tooth- and tissue-supported removable tooth- and tissue-supported removable partial denture.partial denture.

should be universally acceptable.should be universally acceptable.

Classification of Partially Edentulous Classification of Partially Edentulous ArchesArches

To assist our management of partially To assist our management of partially edentulous patientsedentulous patients

Many classifications have been proposed but Many classifications have been proposed but Kennedy classification is the most widely Kennedy classification is the most widely acceptedaccepted

Class II RPDClass II RPD

Kennedy classificationKennedy classification

Was proposed by Dr. Edward Kennedy in Was proposed by Dr. Edward Kennedy in 19251925

Like Bailyn & Skinner classification, it Like Bailyn & Skinner classification, it classifies the partial edentulous arches in a classifies the partial edentulous arches in a manner that suggests principles of design for manner that suggests principles of design for a given situationa given situation


He classified the partial edentulous arches He classified the partial edentulous arches into into four basic classesfour basic classes

The other edentulous areas that donot The other edentulous areas that donot determine the class are considered as determine the class are considered as modification spacesmodification spaces


Class I: Class I: Bilateral edentulous areas located posterior Bilateral edentulous areas located posterior to natural teethto natural teeth

Class II: Class II: A unilateral edentulous area located A unilateral edentulous area located posterior to remaining natural teethposterior to remaining natural teeth

Class III: Class III: A unilateral edentulous area with natural A unilateral edentulous area with natural teeth remaining anterior and posterior to itteeth remaining anterior and posterior to it

Class IV: Class IV: A single, but bilateral (crossing the midline) A single, but bilateral (crossing the midline) edentulous area located anterior to remaining edentulous area located anterior to remaining natural teethnatural teeth

Applegate’s Rules for Applying Applegate’s Rules for Applying the Kennedy Classificationthe Kennedy Classification

Rule 1: Rule 1: the classification should follow, not precede the classification should follow, not precede extractions.extractions.

Rule 2:Rule 2: if a 3 if a 3rdrd molar is missing and not to be replaced, it’s not molar is missing and not to be replaced, it’s not considered in the classification.considered in the classification.

Rule 3:Rule 3: if a 3 if a 3rdrd molar is present and to be used as an abutment, molar is present and to be used as an abutment, it’s considered in the classification.it’s considered in the classification.

Rule 4:Rule 4: if a 2 if a 2ndnd molar is missing and not to be replaced, it’s not molar is missing and not to be replaced, it’s not considered in the classification.considered in the classification.

Rule 5: the most posterior area always determines the classification.Rule 6: edentulous areas other then those determining the classification are referred to as modifications and are designated by their numbers.Rule 7: the extent of the modification is not considered, only the number of additional edentulous areas.Rule 8: there are no modification areas in a K Class IV.

What are the Available Options What are the Available Options to Manage This?to Manage This?



Missing Teeth May Be Replaced By Missing Teeth May Be Replaced By One of Three Prosthesis Types: One of Three Prosthesis Types: **

1.1. An implant-supported fixed partial An implant-supported fixed partial denturedenture

2.2. A tooth-supported fixed partial denture A tooth-supported fixed partial denture (FPD) (FPD)

3.3. A removable partial denture (RPD)A removable partial denture (RPD)

4.4. No replacementNo replacement

Alternatives to RPD (Treatment Alternatives to RPD (Treatment Options)Options)

1. Implant-supported prosthesis 1. Implant-supported prosthesis – most – most costly, closest replacement to natural costly, closest replacement to natural dentition, less costly over long termdentition, less costly over long term

2. Fixed partial denture 2. Fixed partial denture – requires abutments – requires abutments at opposite ends of edentulous space, more at opposite ends of edentulous space, more expensive than RPD, must grind down expensive than RPD, must grind down abutments, flexes and can fail if too longabutments, flexes and can fail if too long

3. No treatment3. No treatment

No Treatment No Treatment

If a patient presents with a long-standing If a patient presents with a long-standing edentulous space into which there has been edentulous space into which there has been little or no drifting or elongation of the little or no drifting or elongation of the adjacent or opposing teeth, the question of adjacent or opposing teeth, the question of replacement should be left to the patient's replacement should be left to the patient's wishes.wishes.

If the patient perceives no functional, occlusal, If the patient perceives no functional, occlusal, or esthetic impairment, it would be a dubious or esthetic impairment, it would be a dubious

service to place a prosthesis.service to place a prosthesis.**

No Treatment (Shortened Dental No Treatment (Shortened Dental Arch)Arch)

Most patients can Most patients can function with a function with a shortened dental shortened dental arch (SDA)arch (SDA)

RPD doesn’t usually RPD doesn’t usually improve function in improve function in shortened dental shortened dental arch casesarch cases

Shortened Dental ArchShortened Dental Arch

Requires anterior teeth Requires anterior teeth + 4 occlusal units + 4 occlusal units (symmetric loss) or 6 (symmetric loss) or 6 occlusal units occlusal units (asymmetric loss) for (asymmetric loss) for acceptable function-acceptable function-

Opposing PM =1 unit, Opposing PM =1 unit, opposing molars = 2 opposing molars = 2 unitsunits

Indications of RPDIndications of RPD

A removable partial denture should A removable partial denture should be considered only when a fixed be considered only when a fixed restoration (either tooth-supported restoration (either tooth-supported or implant-supported) is or implant-supported) is contraindicatedcontraindicated

Indications of RPD * (Span Indications of RPD * (Span Length)Length) Edentulous spaces greater than two Edentulous spaces greater than two

posterior teeth, anterior spaces greater posterior teeth, anterior spaces greater than four incisors, or spaces that include than four incisors, or spaces that include a canine and two other contiguous teeth; a canine and two other contiguous teeth; i.e, central incisor, lateral incisor, and i.e, central incisor, lateral incisor, and canine; lateral incisor, canine, and first canine; lateral incisor, canine, and first premolar; or the canine and both premolar; or the canine and both premolars.premolars.

Indications of RPD (Distal Indications of RPD (Distal Extension Situations)Extension Situations)

An edentulous space An edentulous space with no distal with no distal abutment will abutment will usually require an usually require an RPD, especially when RPD, especially when implant treatment is implant treatment is not feasible for the not feasible for the patient. patient. **

Distal Extension SituationsDistal Extension Situations

To minimize the leverage To minimize the leverage effect, the pontic should be effect, the pontic should be kept as small as possible, kept as small as possible, more nearly representing a more nearly representing a premolar than a molar . premolar than a molar .

There should be light There should be light occlusal contact with occlusal contact with absolutely no contact in any absolutely no contact in any excursion. excursion.

The pontic should possess The pontic should possess maximum occlusogingival maximum occlusogingival height to ensure a rigid height to ensure a rigid prosthesis.prosthesis.

Indications of RPD (After Recent Indications of RPD (After Recent Extractions)Extractions)

Replacement of teeth after recent extractions often Replacement of teeth after recent extractions often cannot be accomplished satisfactorily with a fixed cannot be accomplished satisfactorily with a fixed restoration. When relining will be required later restoration. When relining will be required later or when a fixed restoration using natural teeth or or when a fixed restoration using natural teeth or implants will be constructed later, a temporary implants will be constructed later, a temporary RPD can be used. RPD can be used.

Indications of RPD (Abutment Indications of RPD (Abutment Alignment) Alignment)

Tipped teeth adjoining Tipped teeth adjoining edentulous spaces and edentulous spaces and prospective abutments prospective abutments with divergent with divergent alignments may lend alignments may lend themselves themselves more readily more readily to utilization as RPD to utilization as RPD rather than FPD rather than FPD abutments, if implant abutments, if implant therapy is not amenable.therapy is not amenable.

Indications of RPD (Need for Indications of RPD (Need for Effect of Bilateral Stabilization)Effect of Bilateral Stabilization)

Periodontally weakened primary Periodontally weakened primary abutments may serve better in retaining abutments may serve better in retaining a well designed removable partial a well designed removable partial denture than in bearing the load of a denture than in bearing the load of a fixed partial denture. fixed partial denture. **

Avoid Unilateral RPDAvoid Unilateral RPD

Indications of RPD (Abutment Indications of RPD (Abutment condition)condition) Teeth with Teeth with short clinical crowns short clinical crowns or or

teeth that are just generally short teeth that are just generally short usually will not be good FPD usually will not be good FPD abutments.abutments.

Unusually Unusually sound abutment teethsound abutment teeth

Indications of RPD (Abutment Indications of RPD (Abutment Condition)Condition)

An insufficient An insufficient number of number of abutments may also abutments may also be a reason for be a reason for selecting a selecting a removable rather removable rather than FPD, if than FPD, if implant therapy is implant therapy is not amenable.not amenable.

Indications of RPD (Excessive Indications of RPD (Excessive Loss of Residual Bone)Loss of Residual Bone)

If there has been a If there has been a severe loss of tissue severe loss of tissue in the edentulous in the edentulous ridge, an RPD can ridge, an RPD can more easily more easily be used be used to restore the space to restore the space both functionally both functionally and esthetically.and esthetically.

Gingival Reconstruction with Gingival Reconstruction with FPDFPD

Indications of RPD ( Economic Indications of RPD ( Economic Considerations)Considerations)

Economics should not be the sole criterion in Economics should not be the sole criterion in arriving at a method of treatment. arriving at a method of treatment.

When for economic reasons, complete treatment is When for economic reasons, complete treatment is out of the question and yet replacement of missing out of the question and yet replacement of missing teeth is indicated, the restorative procedures dictated teeth is indicated, the restorative procedures dictated by these considerations must be described clearly to by these considerations must be described clearly to the patient as the patient as a compromise and not representative a compromise and not representative

of the best that modern dentistry has to offerof the best that modern dentistry has to offer. . **

Usually, any missing Usually, any missing anterior teeth in a anterior teeth in a partially edentulous partially edentulous arch are best replaced arch are best replaced by means of a fixed by means of a fixed restoration. Then, the restoration. Then, the replacement of missing replacement of missing posterior teeth is made posterior teeth is made with an RPD .with an RPD .**

Combination of RPD and FPDCombination of RPD and FPD

When an edentulous space When an edentulous space that is a modification of that is a modification of either a Class I or Class either a Class I or Class II arch exists anterior to II arch exists anterior to a lone-standing abutment a lone-standing abutment tooth, the splinting of this tooth, the splinting of this abutment to the nearest abutment to the nearest tooth by FPD is tooth by FPD is mandatory. mandatory. **



Eliminate all but one Eliminate all but one posterior edentulous posterior edentulous space per quadrant space per quadrant by using an FPD to by using an FPD to simplify the RPD simplify the RPD design. design.

Removable Partial DentureRemovable Partial Denture

Dry mouth poor RPD Dry mouth poor RPD riskrisk

Limited patient Limited patient financesfinances

Acceptable oral hygieneAcceptable oral hygiene Reliable recall Reliable recall

candidatecandidate Treatment Treatment

simplificationsimplification

Advanced ageAdvanced age Systemic health Systemic health

problemsproblems More adaptable to More adaptable to

dentition in dentition in transition to transition to edentulous stateedentulous state

Conventional Tooth-Supported FPDConventional Tooth-Supported FPD

Dry mouth high caries Dry mouth high caries riskrisk

Muscular Muscular discoordinationdiscoordination

Mandibular toriMandibular tori Palatal soft tissue Palatal soft tissue

lesionslesions Large tongueLarge tongue Exaggerated gag reflexExaggerated gag reflex

Unfavorable attitude Unfavorable attitude toward RPDtoward RPD

Patient can't cope with Patient can't cope with aging, tooth lossaging, tooth loss

Favorable opposing Favorable opposing occlusionocclusion

Periodontally weakened Periodontally weakened natural dentition may natural dentition may permit FPD in less than permit FPD in less than optimal situationsoptimal situations

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 unit of an RPD The unit of an RPD that connects the parts that connects the parts of one side of the of one side of the dental arch to those of dental arch to those of the other side. the other side.

Its principal functions Its principal functions are to provide are to provide unification and rigidity unification and rigidity to the denture.to the denture.

(b)(b) Minor Connector: Minor Connector:

A unit of a partial denture A unit of a partial denture that connects other that connects other components (i.e. direct components (i.e. direct retainer, indirect retainer, retainer, indirect retainer, denture base, etc.) to the denture base, etc.) to the major connector.major connector.

The principle functions of The principle functions of minor connectors are to minor connectors are to provide unification and provide unification and rigidity to the denture.rigidity to the denture.

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

that provides retention that provides retention against dislodging forces.against dislodging forces.

A direct retainer is A direct retainer is commonly called a 'clasp' or commonly called a 'clasp' or 'clasp unit' and is composed 'clasp unit' and is composed ofof

four elements, a rest, a four elements, a rest, a retentive arm, a reciprocal retentive arm, a reciprocal arm and a minor connector.arm and a minor connector.

(d)(d) Indirect Retainer: Indirect Retainer: A unit of a Class I or II A unit of a Class I or II

partial denture that partial denture that prevents or resists prevents or resists movement or rotation of movement or rotation of the base(s) away from the base(s) away from the residual ridge. the residual ridge.

The indirect retainerThe indirect retainer

is usually composed of is usually composed of one component, a rest.one component, a rest.

(e) (e) Denture Base: Denture Base:

The unit of a partial The unit of a partial denture that covers denture that covers the residual ridges the residual ridges and supports the and supports the denture teeth.denture teeth.

ReferencesReferences

McCracken’s Removable Prosthodontics, 11McCracken’s Removable Prosthodontics, 11thth Edition 2005 by McGivney GP, Carr AB. Edition 2005 by McGivney GP, Carr AB. Chapter 2 and 3Chapter 2 and 3

McCracken’s Removable Prosthodontics, 11McCracken’s Removable Prosthodontics, 11thth Edition 2005 by McGivney GP, Carr AB. Edition 2005 by McGivney GP, Carr AB. Chapter 12 Diagnosis and Treatment Planning Chapter 12 Diagnosis and Treatment Planning P 215-220P 215-220

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Introduction to Removable Partial Prosthodontics