DENTURE BASES

FunctionsFunctions Support & retain denture teeth Support & retain denture teeth Stress distribution - surface area Stress distribution - surface area Improve esthetics Improve esthetics Support & retain denture teeth Support & retain denture teeth Stress distribution - surface area Stress distribution - surface area Improve esthetics Improve esthetics

MaterialsMaterials Acrylic Resin Acrylic Resin Metal Metal Acrylic Resin Acrylic Resin Metal Metal

Acrylic Resin Bases Most common type Most common type Allows relining of the base to maintain mucosal support Allows relining of the base to maintain mucosal support Most common type Most common type Allows relining of the base to maintain mucosal support Allows relining of the base to maintain mucosal support

AdvantagesAdvantages Esthetically superior to metal bases Esthetically superior to metal bases Ease of repair Ease of repair Esthetically superior to metal bases Esthetically superior to metal bases Ease of repair Ease of repair

DisadvantagesDisadvantages Dimensional stability- warpage Dimensional stability- warpage Lower strength/wear resistance than metal Lower strength/wear resistance than metal Porous - hygiene Porous - hygiene Low thermal conductivity Low thermal conductivity Dimensional stability- warpage Dimensional stability- warpage Lower strength/wear resistance than metal Lower strength/wear resistance than metal Porous - hygiene Porous - hygiene Low thermal conductivity Low thermal conductivity

Metal Bases Small edentulous spaces (no room for gridwork Small edentulous spaces (no room for gridwork Less esthetic (metal show through) Less esthetic (metal show through) Small edentulous spaces (no room for gridwork Small edentulous spaces (no room for gridwork Less esthetic (metal show through) Less esthetic (metal show through)

Beaded Metal Base

Metal Filled Space

Retentive Posts

AdvantagesAdvantages Thermal conductivity Thermal conductivity –Swallowing hot substances –Improved thermal perception Thermal conductivity Thermal conductivity –Swallowing hot substances –Improved thermal perception

AdvantagesAdvantages Accuracy & Dimensional Stability Accuracy & Dimensional Stability –Minimal warpage (casting imbibtion) –Minimal need for a posterior palatal seal –Minimal abrasion Accuracy & Dimensional Stability Accuracy & Dimensional Stability –Minimal warpage (casting imbibtion) –Minimal need for a posterior palatal seal –Minimal abrasion

AdvantagesAdvantages Hygiene Hygiene –Metal less porous than resin –Less food, plaque & calculus accumulation Hygiene Hygiene –Metal less porous than resin –Less food, plaque & calculus accumulation

AdvantagesAdvantages Weight and Bulk Weight and Bulk –Metal bases can be cast thinner than resin bases while maintaining adequate strength Weight and Bulk Weight and Bulk –Metal bases can be cast thinner than resin bases while maintaining adequate strength

Flange Extension Tooth- tissue supported partial dentures should be maximally extended for support & retention Tooth- tissue supported partial dentures should be maximally extended for support & retention No overextension or impingement on movable border tissues No overextension or impingement on movable border tissues Tooth- tissue supported partial dentures should be maximally extended for support & retention Tooth- tissue supported partial dentures should be maximally extended for support & retention No overextension or impingement on movable border tissues No overextension or impingement on movable border tissues

Flange Extension Class I & II RPDs Class I & II RPDs –Posterior extension same as a complete denture –Hamular notches, retromolar pads Class I & II RPDs Class I & II RPDs –Posterior extension same as a complete denture –Hamular notches, retromolar pads

Flange Extension Soft Tissue Undercuts Soft Tissue Undercuts

Acrylic Resin Finish Lines Internal & external finish lines should not coincide Internal & external finish lines should not coincide

Replacement Teeth Acrylic denture teeth Acrylic denture teeth –Cause less attrition than porcelain –Easier to arrange, modify & adjust Acrylic denture teeth Acrylic denture teeth –Cause less attrition than porcelain –Easier to arrange, modify & adjust

Replacement Teeth Tooth Form Tooth Form –Harmonize with adjacent teeth –Shade, shape, length, width & occlusal form –Occlusion almost always requires adjustment Tooth Form Tooth Form –Harmonize with adjacent teeth –Shade, shape, length, width & occlusal form –Occlusion almost always requires adjustment

Replacement Tooth Modification

Occlusal Scheme Varies from fully balanced (opposing a complete denture), to anterior disclusion Varies from fully balanced (opposing a complete denture), to anterior disclusion As more of the occlusal table is involved, the more a balanced occlusal scheme may be of benefit As more of the occlusal table is involved, the more a balanced occlusal scheme may be of benefit Varies from fully balanced (opposing a complete denture), to anterior disclusion Varies from fully balanced (opposing a complete denture), to anterior disclusion As more of the occlusal table is involved, the more a balanced occlusal scheme may be of benefit As more of the occlusal table is involved, the more a balanced occlusal scheme may be of benefit