Dental Prosthetics: Occlusion Blocks & Denture Bases

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Questions and Answers

What is the primary purpose of using occlusion blocks in denture fabrication?

To reduce the overall weight of the denture

To establish and maintain the vertical dimension of occlusion (correct)

To enhance the aesthetic appearance of the denture

To aid in the selection of shade for denture teeth

Which is NOT a requirement of a trial denture base?

Easy to construct

Heavily textured surface for grip (correct)

Dimensionally stable with minimal warpage

Accurately adapted to the cast with proper extensions

What materials are used in the fabrication of the record base?

Polyvinyl siloxane

Self-curing epoxy resin

Autopolymerizing acrylic resin (correct)

Thermoplastic polyurethane

What is the first step in the process of preparing the master cast for record base fabrication?

Blocking out undercuts with base plate wax Signup and view all the answers

Why is the master cast soaked in room temperature water before fabricating the record base?

To expel air and minimize bubble formation Signup and view all the answers

How many layers of tinfoil substitute are applied to the cast?

Two layers with the first allowed to dry before adding a second Signup and view all the answers

Which area of the maxillary cast is primarily considered when blocking out undercuts or irregularities?

Labial of the anterior ridge and rugae areas Signup and view all the answers

What is an essential characteristic of a trial denture base to ensure convenience during procedure?

It should be easily removable from the cast Signup and view all the answers

What is the primary purpose of occlusion rims in denture fabrication?

To facilitate registration of jaw relationships Signup and view all the answers

What is the recommended width of occlusal rims in the anterior region?

6–8 mm Signup and view all the answers

How far anterior should the labial surface of the maxillary occlusion rim be from the midline of the incisive papilla?

6–8 mm Signup and view all the answers

What important information must be communicated to patients regarding record bases and occlusion rims?

They may feel a little loose due to required blocked-out undercuts. Signup and view all the answers

What is the typical vertical height of a mandibular occlusion rim?

18 mm Signup and view all the answers

What is the purpose of the canine lines in the occlusion rim?

To indicate the width of the posterior teeth Signup and view all the answers

Which of the following is true about the width of occlusal rims in the posterior region?

It is generally 8–10 mm. Signup and view all the answers

What could be a potential issue when arranging denture teeth related to the record base?

Limited space at the crest of the ridges Signup and view all the answers

Study Notes

Occlusion Blocks

Occlusion blocks consist of occlusion rims attached to well-fitting trial denture bases.
They are crucial for establishing facial contours, aiding in tooth selection, establishing and maintaining vertical dimension of occlusion during records making, making interocclusal records, arranging denture teeth, and creating a waxed-up mold for the external surface of the complete denture.

Trial Denture Base Requirements

Trial denture bases should be rigid, accurately adapted to the cast with proper extensions, dimensionally stable with minimal warpage during use, relieved from any undercuts to avoid scraping the cast during insertion and removal, clean and smooth for patient comfort, have a proper & uniform thickness of 2 mm, and be easy to construct.

Wax Block Out

To protect master casts, tissue undercuts and irregularities are blocked out with base plate wax.
Locations for undercuts or irregularities on the maxillary casts are on the labial of the anterior ridge, rugae areas, and sometimes in the tuberosity areas laterally.
On the mandibular cast, block out the retromylohyoid areas.

Cast Preparation

After blocking out the master cast, soak it in room temperature water for 5 minutes to expel air and minimize bubble-like defects.
Apply a tinfoil substitute as a separating medium to protect the cast and allow separation of the record base.
Apply the tinfoil substitute in two thin layers, allowing the first to dry before applying the second.
Apply a thin film to all surfaces of the cast, including land areas and the sides of the base that may come in contact with the resin.

Record Base Fabrication

Fabricate record bases with autopolymerizing acrylic resin.
The record base should be thinner on the crest of the ridges and buccal to the crest of the ridges to allow for adequate space when arranging denture teeth.

Occlusion Rim Fabrication

Occlusion rims are generally made of pink modeling wax.
Their uses include registration of jaw relationships, choice of artificial teeth (including midline, high and low lip lines, canine lines, and posterior tooth width), setting-up of teeth, and support for lip and cheeks.

Occlusion Rim Dimensions

Occlusion rims should be approximately 8-10 mm wide in the posterior and 6-8 mm wide in the anterior region.
The labial surface of the maxillary occlusion rim in the central area should be approximately 6-8 mm anterior to the middle of the incisive papilla and is inclined labially.
The vertical height of the mandibular occlusion rim is about 18 mm.
In the posterior lower region, the height is equal to two-thirds the height of the retromolar pad (middle to upper third).

Important Patient Information

Continuously inform patients that record bases and occlusion rims are not part of the completed dentures and may feel a little loose because of the blocked-out undercuts.

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Description

This quiz covers essential concepts related to occlusion blocks and trial denture base requirements. You'll learn about their functions, qualities, and the importance of wax block out in protecting master casts. Test your knowledge to ensure a strong grasp of dental prosthetics.