2nd year pre clinical RPD Terminology, Components and Classification of partially edentulous arches

Partially Edentulous Terminology

Components of a Removable Partial Denture (RPD)

Classification of Partially Edentulous Arches

PARTIALLY EDENTULOUS TERMINOLOGY

• Removable Prosthodontics

The branch ofProsthodontics concernedwith replacement of teethand contagious structuresof edentulous or partiallyedentulous patients byartificial substitutes that arereadily removable frommouth.

• Removable Dental Appliance

Devices worn by the patientin the course of treatmentand that can be insertedand removed at will.

For example, occlusalsplints, removable partialdenture, orthodonticsappliances, an obturatoretc.


• Removable Partial Denture Prosthesis

Any prosthesis thatreplaces some teeth ina partially dentate arch.It can be placed andremoved from mouth atwill.


• Interim or Provisional Denture

Dental prosthesis used for ashort time for reasons ofesthetics, mastication,occlusal support,convenience or forconditioning a patient to anartificial substitute formissing natural teeth until amore definite dentalprosthesis can be provided.


• SUPPORT : The foundation on which a dental prosthesis rests.

• STABILITY : Quality of a prosthesis to be firm, stable or constant and to resist displacement by functional, horizontal or rotational stresses.

• RETENTION : Quality inherent in the prosthesis to resist vertical forces acting to displace it away from its foundation.


• ABUTMENT

An abutment is tooth,

a portion of a tooth or

a portion of an implant that serves to support or retain a prosthesis.


• HEIGHT OF CONTOUR

A lines encircling a tooth, designating its greatest circumference at a selected position determined by a dental surveyor.


• UNDERCUT :

Portion of a tooth that lies between the HOC and the gingiva.


• Angle of Cervical Convergence

Angle viewed between a vertical rod contacting an abutment tooth and the axial surface of the abutment cervical to the height of contour.


• Guiding Planes

Two or more parallel surfaces of abutment teeth shaped to direct a prosthesis during its placement and removal.


DENTAL CAST SURVEYOR:

An instrument used to determine the relative parallelism of two or more axial surfaces of teeth or other parts of a cast of a dental arch.


• IMPRESSSION

A negative likeness or copy in reverse of a surface or an object.

(teeth and adjacent structures)


• DENTAL CAST :

An accurate and a positive replica of a maxillary or mandibulardental arch.

COMPONENTS OF A REMOVABLE PARTIAL DENTURE (RPD)


– Major connector

– Minor connector

– Direct retainer

– Indirect retainer

– Rests

– Stabilizing/reciprocal component

– Denture base.

Framework for mandibular removable partial denture with the following components:

1, lingual bar major connector.

2a, minor connector by which the

resin denture base will be attached.

2b, minor connector, proximal plate,

which is part of clasp assembly.

2c, minor connector used to connect

rests to major connectors.

3, occlusal rests.

4, direct retainer arm, which is part

of the total clasp assembly.

5, stabilizing or reciprocal

components of clasp assembly (includes minor connectors).

6, an indirect retainer consisting of a

minor connector and an occlusal rest.

Framework for maxillary removable partial denture with the following components:

A : A-P palatal strap type

major connector

B : Minor connector

C : Direct retainer

D : Occlusal Rest


• MAJOR CONNECTOR

Connects the parts of a prosthesis located on one side of the arch with those located on the opposite side.

• Other functions :

Cross arch stability to help resist displacement by functional forces.


• Mandibular major connectors

– Lingual bar – Linguoplate– Sublingual bar– Lingual bar with cingulum

bar (continuous bar)– Cingulum bar– Labial bar

• Maxillary major

– Single palatal strap– Combination anterior and

posterior palatal strap–type Connector

– Palatal plate-type connector

– U-shaped palatal connector

– Single palatal bar– Anterior-posterior palatal

bars


• MINOR CONNECTOR

Connecting link between the major connector/base of an PRDP and other components of the prosthesis such as, clasp assembly, occlusal rests. Etc.


• DIRECT RETAINER

– Retains a PRDP and prevents its dislodgment.

– May be placed extracoronally (clasp assembly) or intracoronally (precison attachments)


• EXTRA CORONAL DR • INTA CORONAL DR


• REST Provides vertical support.

• REST SEAT Prepared surface on an abutment to receive the rest.

Types :• Occlusal rest• Cingulum rest• Incisal rest

• Other fuctions :

– Maintains components in their planned positions.

– Maintains occlusal relation-ships.

– Prevents settling of denture.

– Prevents impingement on soft tissues.

– Distributes and directs occlusalloads along long axis.


• INDIRECT RETAINER

– Assists a direct retainer in preventing displacement of a distal extension denture base by functioning through lever action on opposite side of a fulcrum line when denture base moves away from the tissue in pure rotation around the fulcrum line.


• Indirect retainers may consist of / take form of :

– Auxiliary occlusal rest

– Vertical supporting minor connector

– Proximal plates adjacent to edentulous areas.


• STABILIZING/RECIPROCAL COMPONENTS:

• Imparts stability to RPDP against functional, horizontal and rotational stresses.

• Provided by:

– Reciprocal/ stabilizing arm of clasp assembly.

– Major connector (CAS)

– Vertical supporting minor connector (together with Maj. Connector.)


• DENTURE BASE :

Rests on the foundation tissues and to which teeth are attached.

CLASSIFICATION OF PARTIALLY EDENTULOUS ARCHES


• Requirements of an AcceptableMethod of Classification

• It should permit immediate visualization of the type ofpartially edentulous arch that is being considered.

• It should permit immediate differentiation between the tooth-supported and the tooth- and tissue-supported removable partialdenture.

• It should be universally acceptable.


• KENNEDY CLASSIFICATION

• Dr. Edward Kennedy in 1925

• Kennedy divided all partially edentulous arches into four basic classes.

• Edentulous areas other than those that determine the basic classes were designated as modification spaces.

KENNEDY CLASSIFICATION

• Class I :

– Bilateral edentulous areas located posterior to the natural teeth.


• Class II :

– A unilateral edentulous area located posterior to the remaining natural teeth.


• Class III :

– A unilateral edentulous area with natural teeth remaining both anterior and posterior to it.


• Class IV :

– A single, but bilateral (crossing the midline), edentulous area located anterior to the remaining natural teeth.

RULES GOVERNING APPLICATION OF THE KENNEDY METHOD

• Rule 1

– Classification should follow rather than precede any extractions of teeth that might alter the original classification.

• Rule 2

– If a third molar is missing and is not to be replaced, it is not considered in the classification.


• Rule 3

– If a third molar is present and is to be used as an abutment, it is considered in the classification.

• Rule 4

– If a second molar is missing and is not to be replaced, it is not considered in the classification (e.g., if the opposing second molar is likewise missing and is not to be replaced).


• Rule 5

– The most posterior edentulous area (or areas) always determines the classification.

• Rule 6

– Edentulous areas other than those that determine the classification are referred to as modifications and are designated by their number.


• Rule 7– The extent of the modification is not considered,

only the number of additional edentulous areas.

• Rule 8– No modification areas can be included in Class IV

arches. (Other edentulous areas that lie posterior to the single bilateral areas crossing the midline would instead determine the classification; see Rule 5.)

EXERCISE

2nd year pre clinical RPD Terminology, Components and Classification of partially edentulous arches

Health & Medicine

Transcript of 2nd year pre clinical RPD Terminology, Components and Classification of partially edentulous arches