Removable partial denture

Removable partial denture

Introduction & Classification Lec. Reem N. Alirhayim

Effects of tooth loss

Morphological, functional effectsand social effects• Movement of teeth – tilting, migration andovereruption• Alteration of occlusal plane• Alteration of path of mandibular closure• Alveolar bone resorption• Appearance• Mastication and speech• Psychological effects

What is prosthetics dentistry?

That branch of dentistry that deals with the replacement of missing teeth, and/or the replacement of missing tooth tissues Fixed prosthodontics (crowns/bridges) Removable prosthodontics (dentures) [implant retained/supported prosthodontics]

RPD - definition

A prosthesis that replaces one or more, but not all of the natural teeth and supporting structures. It can be removed and replaced in the mouth by the patient.

Treatment Objectives: 1. preserve remaining teeth and supporting structures 2. restore esthetics and phonetics 3. restore and/or improve mastication 4. restore health, comfort and quality of life

Treatment options for the partiallydentate patient1• No treatment – accept SDA2.Fixed restorations – adhesive orconventional bridges3• Removable partial dentures4• Implant retained restorations – fixed orremovable


Indications for RPDs
1. lengthy edentulous span (too long for a fixed prosthesis) 2. no posterior abutment for a fixed prosthesis 3. excessive alveolar bone loss (esthetic problem)

Indications for RPDs

14. poor prognosis for complete dentures due to residual ridge morphology 5. reduced periodontal support of remaining teeth (won't support a fixed prosthesis) 6. cross-arch stabilization of teeth 7. need for immediate replacement of extracted teeth 8. cost/patient desire considerations

The component parts of RPD

RPD Components
Connectors
Major Connectors Minor Connectors
Retainers
Direct Retainers Indirect Retainers
Rests
Occlusal Rest Cingulum Rest Incisal Rest Occlusal Onlays Embrasure Hooks
One or more Denture bases
Teeth replacements

"That part of the denture that rests on the oral mucosa and carry the artificial teeth"or alternatively "The space(s) to be filled by the denture“Classification of SaddlesBounded Saddles(teeth present at both ends of the saddle area)Free-end saddles(teeth present at only the anterior end of the saddle) Denture Base (Saddle)

Support

"The resistance to a vertical displacing force directed towards the mucosa“

Retention

"That quality inherent in a prosthesis acting to resist movement or displacement away from the mucosa”Mechanical RetentionAchieved in RPD prosthodontics by the use of clasps. Or attachments

Stability:

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

Classification of RPDRequirements of an acceptable method of classification

It should be permit immediate visualization of the type of partially edentulous arch being considered. It should permit immediate differentiation between the tooth- support and the tooth and tissue- supported RPD. Serve as a guide to the type of design to be used. It should be universally acceptable.
The most familiar classifications are those originally proposed by Kennedy, Cummer, and Bailyn. Classifications have also been proposed by Beckett, Godfrey, Swenson, Friedman, Wilson, Skinner, Appligate, Avent, Miller, and others.

Classification of RPD

Classifications in current use are of two types - those which classify the partial denture and those which classify the partially edentulous arch. A classification which describes partial dentures is based on the nature of the support utilized by a partial denture. Support can be gained from: Teeth-support (born), Mucosa-support, Teeth and mucosa-support.

Classification of RPD

According to support: Teeth-support (born), Mucosa-support, Teeth and mucosa-support



Classification of RPDKennedy’s Classification Kennedy divided all partially edentulous arches into 4 clases based on the location of the edentulous area/s as follows: Class I: Bilateral edentulous areas located posterior to the remaining natural teeth. Class II: A unilateral edentulous area located posterior to the remaining natural teeth. Class III: A unilateral edentulous area located between the remaining natural teeth. Class IV: A single, but Bilateral (crossing the midline), edentulous area located anterior to the remaining natural teeth.
By Dr.Edward Kennedy,(1925)

Classification of RPDKennedy’s Classification Class I

Class III
Class VI
Class II

KENNEDY CLASS I -

CLASS I - Bilateral Posterior Edentulous Areas

KENNEDY CLASS II -

CLASS II - Unilateral Posterior Edentulous Area

KENNEDY CLASS III

CLASS III - Unilateral Edentulous Area(s) bounded by Remaining Tooth/Teeth
UNILATERAL

KENNEDY CLASS IV

What about the following cases ?


Kennedy’s ClassificationApplegate rules Applegate (1960) provided the following 8 rules to governed the application of the Kennedy classification: Rule 1. Classification should follow rather than precede extractions that might alter the original classification. Rule 2. If the third molar is missing and not to be replaced, it is not considered in the classification Rule 3. If the third molar is present and is to be used as an abutment, it is considered in the classification Rule 4. If the second molar is missing and not to be replaced, it is not considered in the classification Rule 5. The most posterior edentulous area/s determine the classification. Rule 6. The edentulous areas other than those determine the classification are referred to as modification spaces and are designated by their number. Rule 7. The extent of the modification is not considered, only the no. of additional edentulous areas. Rule 8. There can be no modification areas in Class IV arches.

CLASSIFICATION WITH MODIFICATION AREAS

Class II mod 1
Class II mod 2 CLASS II mod 3 Class II mod 1

By using Applegate rules, Kennedy classification is an anatomical classification which describes the number and distribution of edentulous areas present.
Class I, Modification 1. Class III, Modification 2. Class II, Modification 1. Class IV, ????


H.W 1. Define: Undercute, abutment, clasp, surveyor. 2. Give the Kennedy classification of the following cases


(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(16)
(12)
(11)
(10)
(13)
(9)
(15)
(14)
Class I, Modification 1.

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