30 Questions
What is the main advantage of using a chrome cobalt alloy for a denture base?
It is more accurate and rigid even in thin sections
Why is stainless steel less commonly used for denture bases compared to chrome cobalt alloy?
Stainless steel is less accurate than chrome cobalt
What is the main reason gold is sometimes used for lower partial dentures?
Gold has a higher specific gravity to help with retention
What is the primary reason acrylic resin may be used for the denture base of a partial denture?
Acrylic resin is used mainly for temporary removable partial dentures
What is the main disadvantage of using stainless steel for a denture base?
Stainless steel is less accurate than chrome cobalt
Which of the following is NOT a type of denture base material mentioned in the text?
Titanium alloy
Which of the following is NOT an advantage of a metal base compared to a non-metallic one?
Bad esthetics
What is the purpose of having a space between the metal framework and the tissues in a combined metal and acrylic base partial denture?
To allow for easy relining of the denture
What is the purpose of the mesh or latticework design of the metal framework in a combined metal and acrylic base partial denture?
To provide continuity between the acrylic resin on either side of the metal
Which of the following is a disadvantage of a metal base compared to a non-metallic one?
Difficult to rebase, reline, and repair
What is the purpose of the small tissue stop in the combined metal and acrylic base partial denture design?
To prevent the framework from being displaced when the acrylic resin is packed
Which of the following is a benefit of the combined metal and acrylic base partial denture design?
Easier to rebase, reline, and repair
Which of the following is an indication for using temporary acrylic removable partial dentures?
Patients with short clinical crowns awaiting teeth eruption
What is one of the advantages of non-metallic denture bases mentioned in the text?
Accept relining and repair
Why are acrylic bases made bulky in non-metallic denture bases?
Due to the weakness of the material
In which situation is the presence of acrylic resin in removable partial dentures necessary?
In cases of extreme bone loss
What is a disadvantage of non-metallic denture bases mentioned in the text?
Dimensionally unstable
Why is less thermal conductivity mentioned as a disadvantage of non-metallic denture bases?
It provides less stimulation to underlying tissues
What is the purpose of using a combined metal and acrylic base in cases with severe bone loss?
To cover maximum area of supporting tissue
In which cases should the denture base extend from the abutment to the retro molar pad of the mandible?
Distal extension cases
Why is it important for the contact between the abutment tooth and the saddle to occur at the natural contact point?
To avoid moving the tooth away from the saddle
For which type of cases should the denture flanges be made as long as possible?
Free end saddle cases
What is the reason behind having buccal and lingual extensions in a denture?
To stabilize the denture against horizontal movement
Why should the denture base cover maximum area of supporting tissue?
To distribute stress over a large area
What is the ideal relationship between the denture base and the abutment tooth?
Close contact between the saddle and the proximal surface of the abutment tooth
What is the purpose of angulating the saddle away from the tooth below the contact point?
To create a self-cleaning space
What is the consequence of having a small space between the denture base and the neck of the abutment tooth?
It predisposes to chronic gingivitis and pocket formation
How should proximal undercuts be addressed when they cause a space between the denture base and the abutment tooth?
Grind them away or construct a full coverage crown or inlay
Which of the following gingival conditions is expected when there is close contact between the saddle and the abutment tooth?
Good gingival condition
What is the purpose of creating a self-cleaning space between the saddle and the abutment tooth?
To prevent food packing and gingival inflammation
Study Notes
Metal Base vs Non-Metallic Base
- Metal base is more rigid even in thin sections, making it less bulky.
- Metal base has high thermal conductivity, which stimulates tissues.
- Metal base has better tissue adaptation and compatibility.
- Metal base is more hygienic due to its polished and smooth surface.
Disadvantages of Metal Base
- Difficult to rebase, reline, and repair.
- Bad esthetics.
Combined Metal and Acrylic Base
- Metal and acrylic resin are used together for construction of partial denture.
- The metal is made in a mesh work or latticework to provide continuity between the acrylic resin on either side.
- There should be a space between the metal and the tissues, which is packed with acrylic resin before denture processing.
Indications of Temporary Acrylic Removable Partial Dentures
- For young patients with short clinical crown to restore appearance until teeth eruption are completed.
- For very ill patients whose health contraindicates long clinical prosthetic procedures.
- For patients having only few periodontally weak teeth.
- After recent extraction until proper healing and bone modeling occurs and permanent restoration could be made.
- For economic reasons.
- For cases of extreme bone loss, where the presence of acrylic resin is necessary to restore the original contour of the ridge.
Advantages of Non-Metallic Denture Base
- Good appearance.
- Light in weight.
- Accept relining, rebasing, and repair.
- Less expensive and easy to manipulate.
Disadvantages of Non-Metallic Denture Base
- Weak (brittle and easy to fracture).
- Dimensionally unstable.
- Very less thermal conductivity and less stimulation to underlying tissues.
Types of Denture Base Materials
- Metallic (e.g. Chrome cobalt alloys, gold, stainless steel).
- Non-metallic (e.g. acrylic resin).
- Combination of metallic and non-metallic.
Metallic Base Materials
- Chrome cobalt alloy:
- Used in cast form only.
- Needs special investments and special casting and polishing machine.
- Has high casting temperature (2400°F).
- Advantages: accurate, rigid, low specific gravity, highly polished surface, high resistance to corrosion and abrasion, and cheaper than gold.
- Gold:
- Disadvantages: heavier, more rigid, and more expensive than chrome cobalt alloy.
- Sometimes used for lower partial denture to help in retention due to its specific gravity (weight).
- Stainless steel:
- Used mainly in swaged form.
- Disadvantages: less accurate, less commonly used.
Extension of Denture Base
- The denture base should cover maximum area of supporting tissue as possible.
- The antero-posterior extension: bounded by the abutment teeth for bounded denture, and extending from the abutment to the retro molar pad of the mandible and covering the tuberosity in the maxilla for distal extension cases.
- The buccal and lingual extensions: the denture flanges should be made as long as possible to help stabilize the denture against horizontal movement.
Relationship between Denture Base and Abutment
- The contact between the abutment tooth and the saddle must occur at the natural contact point.
- Close contact or point contact between the saddle and the proximal surface of the abutment tooth is necessary to prevent food packing and trauma to gingival tissues.
- Proximal undercuts should be eliminated by grinding or by the construction of full coverage crown or by inlays to prevent chronic gingivitis and pocket formation.
Explore the various types of denture base materials including metallic, non-metallic, and combinations of both. Learn about the characteristics of metallic bases, their construction, and the materials used.
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