The Component

Parts of

Removable Partial

Dentures

Stages of framework construction from duplicated master cast, through wax pattern, and finally casting in cobalt, chrome alloy. Note lingual reciprocal arms on casting to relate the framework to PFM crown castings

Source: Jeff Shotwell, University of Michigan, 2008

•Removable dental prosthesis (appliance) replacing one or more natural teeth and associated oral structures

Types

The Component

Functions

Requirements of an Ideal ComponentMaterial UsedSpecial Point

Definition

1 -Denture Base

The Component Partsof Removable Partial Dentures

DefinitionThe Denture Base Is the Part of the Denture, Which Rests on the Foundation Tissues and to Which Artificial Teeth Are Attached

DefinitionIt is that part of the denture, which rests on the foundation tissues and to which artificial teeth are attached .It helps in transferring Occlusal stresses to the supporting oral structures

• The Resistance to Tissue Ward Movement

Support

• Distribute the Forces Over the Supporting Sttructure

• Transferring Occlusal Stresses to the Supporting Oral Structures

Types of Denture Bases

1-Bounded Partial Denture Bases

2- Free-end Partial Denture Bases (Distal-extension Base)

Components of a Partial Denture

Bounded Denture Bases

Free-end Partial Denture Bases (Distal-extension Base)

Free-end Partial Denture Bases (Distal-extension Base)

Free-end Partial Denture Bases (Distal-extension Base)

Functions of the Denture Base

3- Provides support

1- Carries the artificial teeth

2- Transfers Occlusal stresses to the supporting str. stimulation by massage of the tissues

4- Provides denture retention by physical means

5- Provides denture bracing

6- Provides stabilization against tipping of the distal-extension dentures

7- Prevent Migration and Over Eruption of the Remaining Teeth

Contribute to the functions ofContribute to the functions of bracing and stabilizationbracing and stabilization

Contribute to the functions ofContribute to the functions of bracing and bracing and stabilizationstabilization

1- Accuracy of adaptation to the tissues

4-Biological acceptability not irritant

Requirements of an Ideal Denture Base Material

8- Esthetically acceptability 9- Low initial cost ,easy manipulation

3-Should have low specific gravity,

2-Sufficient strength

5-Potential for future relining

6-Should allow thermal conductivity necessary for tissue stimulation

7-Can easily be kept clean

• Metallic

Denture Base Material

Denture Base Material• Non metal as acrylic resinA.R.bases attached to metallic denture framework

through metallic minor connectors

Denture Base Material

Non Metal As Acrylic Resin (Temporary Acrylic Removable Partial Dentures)

Denture Base Material

Metallic denture base

3- Greater Thermal Conductivity

1- More Rigid Than Resin Bases Even in Thinner Section

2- Less Bulky

4- Fit More Accurately to d Underlying Tissues

5- More Hygienic as the fitting surface is Polished and non-porous with less Tendency for Food Accumulation

Advantages

Disadvantages of Metal Bases

3- The Colour of Metal Bases Does Not Simulate the Natural Appearance of Oral Tissues

1-Difficult to Rebase or Reline When Ridge Resorption Occurs

2- Difficult to Repair

Used in thinner section than resin bases

*chrome coblt alloy

*cast gold alloy

*stainless steel

*chrome cobalt alloy Used in cast form

Rigid even in thin section

Has low specific gravity (1/2) that of gold

Provide high resistance to corrosion

Not easily abraded

Attain high polish surface

Dimensionally stable

Special machine for casting &polishing

Special investment& high casting temperature

Cast gold alloy

Less rigid than chrome cobalt alloy & more rigid than resin

More heavier than chrome cobalt alloy

Used in lower partial denture to aid in retention

Stainless steel

Used in swage form

Less accurate than chrome cobalte or gold alloy

Less commonly used

Indications;

Tooth supported partial denture

Inadequate intermaxillary space

Non-metallic, Acrylic Resin Denture Bases

3- Easy to Reline, Rebase or Repair

1- Eesthetically is Satisfactory due to Its Pink Colour

2- Light in Weight

4- Needs Simple Processing Procedures

Advantages

Disadvantages of Resin Base

1- Weak, Have Low Tensile Strength, Brittle And Are Liable To Fracture

2- To Attain Enough Strength, Resin Bases are Made Bulky

3- Have Low Thermal Conductivity

4- The fitting surface is porous and not polished bad oral hygiene, bad odour and inflammation of the tissues

INDICATIONS OF RESIN BASE

1- Free-end Saddle Cases

2- Increased Rate of Bone Loss As Diabetic Patients or Patients on Steroid Therapy

3- Cases With Extreme Bone Loss. The Presence of Acrylic Resin Is Necessary to Restore the Original Contour

Indications:

Extension base partial denture

Long span edentulous ridge

Future relining is anticipated in a short time

resin restore contour much more satisfactory than metal

*support is an important consideration in designing saddles

for extension base saddle

*support obtained from underlying structure as residual

ridge, buccal shelf, palate pear shaped pad

*maximum coverage without encroaching on movable tissue

To reduce stress on the abutment teeth

*need for future relining

*when denture cross gingival tissur it should be relieved to

avoid the impinge on gingival tissue which cause irritation

& periodontal damage.

Denture Base Extension

1- Buccally

2- Lingually

3- Posterior Limit

4- Anterior Limit

Denture Base Extension

Denture Base Extension

Denture Base Extension

Max. Denture Base Extension

Relationship of Denture Base to Abutment

1- Close contact

2- Open Contact

Denture Base Extension

Finishing line

Finishing line

Finishing line

Finishing line

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