Denture Bases and Occlusion Blocks

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Questions and Answers

What is the primary function of occlusion blocks in denture fabrication?

To minimize the weight of the denture

To help in tooth selection and maintain vertical dimension (correct)

To adjust the color of the denture

To increase the size of the denture base

Which of the following is NOT a requirement for a trial denture base?

Inconsistent thickness (correct)

Dimensional stability with minimal warpage

Accurately adapted extensions

Rigid construction

What is the purpose of waxing out tissue undercuts on master casts?

To protect the casts from damage (correct)

To improve the aesthetics of the denture

To increase the size of the denture base

To adhere the denture to the gum

How long should the master cast be soaked in water before making the record base?

5 minutes Signup and view all the answers

What is applied as a separating medium to protect the cast during record base fabrication?

Tinfoil substitute Signup and view all the answers

What is a critical requirement related to the thickness of the record base?

Uniformly 2mm throughout Signup and view all the answers

What should be the thickness of the record base on the crest of the ridges?

Thinner than elsewhere Signup and view all the answers

What is the main reason for applying the tinfoil substitute in two thin layers?

To ensure it dries properly on all surfaces Signup and view all the answers

Which of the following areas on the mandibular cast may require block out for undercuts?

Retromylohyoid areas Signup and view all the answers

What is NOT a use of the occlusion rim?

Exact measurement of the retromolar pad Signup and view all the answers

What is the general width of occlusion rims in the posterior region?

8-10 mm Signup and view all the answers

Where is the labial surface of the maxillary occlusion rim positioned relative to the incisive papilla?

Approximately 6-8 mm anterior to it Signup and view all the answers

What is the vertical height of the mandibular occlusion rim?

18 mm Signup and view all the answers

What misconception should patients be informed about regarding record bases and occlusion rims?

They may feel a little loose Signup and view all the answers

What is determined using the occlusion rim during the arrangement of teeth?

The midline and lip lines Signup and view all the answers

What is the height of the posterior lower region of the mandibular occlusion rim relative to the retromolar pad?

Equal to the height of the middle third Signup and view all the answers

Study Notes

Record Base and Occlusion Blocks

Occlusion blocks are composed of occlusion rims attached to well-fitting trial denture bases.
The record base and occlusion rims are essential for establishing facial contours.
They assist in tooth selection and maintaining the vertical dimension of occlusion during record-making.
Interocclusal records are created using these components.
The denture teeth' arrangement is also facilitated by record base and occlusion rims
The external surface of the complete denture's waxed-up mold is also produced using these elements.

Requirements of a Trial Denture Base

A trial denture base should be rigid.
It needs to fit the cast accurately and have proper extensions.
It should maintain dimensional stability with minimal warpage during use.
Undercuts must be relieved to avoid damaging the cast during placement and removal.
The base should be smooth and clean to ensure patient comfort.
A uniform thickness of 2mm is desirable.
The base needs to be easy to construct.

Wax Block Out

Wax block out protects the master casts from tissue undercuts and irregularities.
Base plate wax is used to block out undercuts and/or irregularities.
The labial surface of the anterior ridge, Rugae areas and sometimes the tuberosity areas laterally are areas of concern.
On the mandibular cast, the retromylohyoid areas may need a wax block out.

Soaking the Master Cast

The master cast is soaked in room-temperature water for 5 minutes.
This step expels air from within the stone; minimizing bubble-like defects in the completed record base.

Tinfoil Substitute

A tinfoil substitute is employed as a separating medium to protect the cast and enable the record base's separation.
The tinfoil substitute is applied twice, allowing the first layer to dry before applying the second.
Each layer is applied as a thin film covering all surfaces of the cast, including land areas and any parts that could come into contact with the resin.

Record Base Fabrication

The record base is created using autopolymerizing acrylic resin.
The tinfoil substitute method is used to create the record base by applying it in two thin layers.

Record Base Dimensions

The record base should be thinner on the crest of the ridges and buccal to the crest of ridges.
The base should not block off spaces that denture teeth might need later on.

Occlusion Rim Fabrication and Uses

Occlusion rims are typically created using pink modeling wax.
Occlusion rims are vital for jaw relationship registration.
The rims aid in selecting the proper artificial teeth as they can assist with determining the midline, high and low lip lines, canine lines, and canine line to posterior teeth distance.
They aid in tooth arrangement preparation
Occlusion rims provide support for lips and cheeks

Occlusion Rim Dimensions

Posterior rims are roughly 8-10mm in width.
Anterior rims are roughly 6-8mm in width.
A 22mm vertical height is usually needed for the mandibular occlusion rim.
The posterior area's height corresponds to two-thirds the height of the retromolar pad.
The labial surface of the maxillary occlusion rim in the central area is roughly 6-8 mm anterior to the middle of incisive papilla and is labially inclined.
The record rim and base should not be a part of the finalized dentures.
Inform patients that they will feel slightly loose due to the blocked-out undercuts.

Posterior Palatal Seal (PPS)

The posterior palatal seal area must be prepared.
The varying degrees of compressibility of the tissues (up to 1mm) are marked out accordingly.
The vibrating line establishes the posterior boundary of the PPS
This is defined with a #6 round bur in a depth of 0.5–1mm.
Other regions require smoothening by using Cleoid-Discoid instruments.
The anterior border of the PPS requires feathering.

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Description

This quiz covers the essential components of occlusion blocks and trial denture bases used in dental prosthetics. Learn about their functions, requirements, and how they assist in the dental record-making process. Test your knowledge on the critical aspects of denture design and patient comfort.