Prosthodontics: Denture Components

The Denture Base and Artificial Teeth

Component Parts of Removable Partial Dentures

• Denture Base: Supports artificial teeth and transfers occlusal stresses to tissues.
• Connectors: Include major and minor connectors for stability.
• Supporting Rests: Provide additional support to the denture.
• Retainers: Direct and indirect retainers ensure the prosthesis stays in place.

Types of Denture Bases

• Bounded Partial Denture Bases: Span an area between two abutments.
• Free-end Partial Denture Bases (Distal-extension Bases): One side attached to a natural tooth; the other side is free.

Functions of the Denture Base

• Carries and stabilizes artificial teeth.
• Transfers occlusal stresses and promotes tissue stimulation through massage.
• Provides denture retention and prevents the migration of remaining teeth.
• Offers bracing and stabilization against tipping of distal-extension dentures.

Stabilization and Tipping

• Stabilization: The resistance of a partial denture to tipping or rocking.
• Tipping: Rotation around a fulcrum, affecting the denture's effectiveness.

Requirements for Ideal Denture Base Material

• Accurate tissue adaptation and sufficient strength.
• Low specific gravity and biological acceptability.
• Good finish and thermal conductivity for tissue stimulation.
• Easy maintenance and aesthetic appeal; affordable cost.

Types of Denture Base Material

• Metallic: Often cobalt chromium alloy; preferred for bounded saddle cases.
• Non-metallic: Primarily acrylic resin; used for temporary removable partial dentures.
• Combined: Utilizes both metallic and acrylic materials for free-end cases.

Advantages and Disadvantages of Metallic Denture Bases

• Advantages: More rigid, lightweight, better thermal conductivity, precise fit, and hygienic surface.
• Disadvantages: Challenging to reline, repair, and lacks the natural appearance of oral tissues.

Advantages and Disadvantages of Acrylic Resin Denture Bases

• Advantages: Aesthetically appealing (pink color), lightweight, easy to repair and reline, and simple production.
• Disadvantages: Brittle, low tensile strength, low thermal conductivity, and porous fitting surfaces leading to hygiene issues.

Indications for Acrylic Resin Bases

• Suitable for older patients, post-extraction healing phases, and cost-effective cases.

Combined Metallic and Acrylic Resin Bases

• Ideal for free-end saddle cases, patients with extreme bone loss, and those on specific therapies like steroids.

Methods of Attaching Denture Base

• Common configurations include ladderlike patterns and closed meshwork.
• Tissue stops used to confirm acrylic thickness during fitting.

Denture Base Extension

• Maximum coverage is achieved in buccal, lingual, and posterior directions.
• Should conform to mucosal reflections and consider muscle function.

Relationship of Denture Base to Abutment

• Requires close contact to gingival margin for trauma prevention; provides an open contact area for cleanliness.

Artificial Teeth

• Made from materials such as acrylic resin, porcelain, metal, and combinations thereof, including cross-linked acrylic and Isosit.

Properties of Acrylic vs. Porcelain Teeth

• Acrylic: Lighter, less prone to distortion, chemically bonded to denture bases, and flexible in modification.
• Porcelain: Heavier, requires mechanical retention, highly abrasive, brittle, and difficult to modify.

Properties of Acrylic Resin Teeth

• Low specific gravity and less abrasive.
• Less harsh on tissues and not noisy.
• Can accommodate small interarch distances.

Properties of Porcelain Teeth

• Heavier, noisy in use, mechanical retention needed, and very brittle.

This quiz covers the essential components of removable partial dentures, including the denture base, connectors, and retainers. Test your understanding of these key parts and their functions in prosthodontic practice.