Prosthodontics Record Blocks Overview

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Questions and Answers

What is the purpose of the separating medium?

To strengthen the resin

To help the resin cure faster

To prevent the resin from sticking to the cast (correct)

To create a smoother finish on the cast

At what stage is the resin molded to the cast?

Immediately after mixing

When it reaches the dough stage (correct)

Before mixing

Once it has fully cured

Which step involves the use of a physical barrier?

Blocking out undercuts

Mixing the self-curing resin

Applying the separating medium (correct)

Molding the resin to the cast

What is the main goal of the entire process described?

To create a mold for casting Signup and view all the answers

Which material is NOT included in the list of temporary record bases?

Permanent elastomeric impression material Signup and view all the answers

What type of shellac base plate is characterized by additional reinforcement?

Reinforced shellac base plate Signup and view all the answers

Which of the following is a characteristic of visible light cure acrylic resin?

Cures in the presence of light Signup and view all the answers

What is a primary advantage of using temporary record bases in dental applications?

They are easy to modify and adapt Signup and view all the answers

Which type of acrylic resin is known for setting through a chemical reaction?

Cold cure acrylic resin Signup and view all the answers

What is one of the objectives of the occlusion rim?

To support the facial musculature Signup and view all the answers

What is a requirement for the occlusion rim?

It should have a specific shape Signup and view all the answers

Which of the following is NOT an objective of the occlusion rim?

Measuring the width of the anterior teeth Signup and view all the answers

The use of occlusion rim helps to achieve which of the following?

Ensuring the teeth are properly aligned Signup and view all the answers

What is the relationship between the width of the anterior teeth and the occlusion rim?

The occlusion rim is used to ensure the anterior teeth are properly spaced Signup and view all the answers

Study Notes

Record Blocks (Occlusion Blocks)

These are used in prosthodontics to record the maxillomandibular relationships.
Record bases are temporary denture bases for supporting record rim material to record maxillo-mandibular records.
Purpose of record blocks is to retain the recording medium for maxillo-mandibular relations.
Also aid in accurate jaw relationships transfer to articulator for positioning artificial teeth in trial dentures.
Requirements include rigidity, accuracy, and stability, with smooth, rounded, and polished borders that contact lips, cheeks, and tongue.
They should match the finished denture border dimensions for accurate fit.
Types include temporary and permanent.
Temporary record bases are discarded, replaced by denture base material.
Permanent record bases become part of the finished denture base.

Materials for Temporary Record Blocks (bases)

Shellac base plate:
- Reinforced: strengthened for better stability, but still prone to distortion.
- Stabilized: more resilient than reinforced, but still less rigid than other options.
Cold cure acrylic resin:
- Advantages: good strength and stability; doesn't warp during manipulation; closely fits master casts.
- Disadvantages: requires more time in fabrication and can be difficult to control thickness. Residual monomer can irritate tissues
Visible light cured acrylic resin:
- Advantages: quick curing process.
- Disadvantages: need of special equipments, possible inaccuracies or defects
Vacuum formed vinyl and polystyrene:
- Advantages: easy fabrication, uniform thickness; accurate adaptation to the master cast; good rigidity.
- Disadvantages: can be expensive; difficult to ensure smooth, rounded borders.

Methods of Construction (Cold Cure Acrylic Resin)

Sprinkle on method: monomer is applied to the cast and polymer is added.
Non compression dough (Finger adapted) method: undercuts are blocked out, separating medium applied to the cast, and resin mixed until dough-like; then molded to the cast. Steps include allowing complete polymerization, then removing from cast, smoothing, and polishing borders.

Materials for Temporary Record Blocks (requirements)

Retromolar pad covered.
Thick palate (1–2 mm) and well adapted.
Thin regions labial to the ridge.
No excess flash on land areas of master casts.
Record bases do not rock on master casts.
No porosities or voids on the tissue surface.
Flanges are smooth and rounded.
Tissue surface adequately adapted.

Occlusion Rim Definition and Objectives

Occlusion rims are occlusal surfaces on a record base for maxillomandibular relationship recordings or for use in tooth arrangement.
Objectives:
- Establish jaw relation.
- Select teeth.
  - Determine appropriate lip position (high vs. low smile lines) for proper aesthetic tooth selection based on lip position.
- Set up teeth
- Support facial musculature.
- Orient occlusal plane.

Occlusion Rim Requirements

Position matches anticipated artificial teeth placement.
Securely attached to the base.
Smooth, flat occlusal surface.
Contoured for accurate lip and cheek support.

Occlusion Rim Materials

Wax occlusion rim:
- Bite blocks wax (readymade): pre-fabricated wax blocks.
- Base plate wax sheets (handmade): custom-made wax sheets for easier management in teeth arrangement.
Modeling compound occlusion rim: used for functional recording of jaw relations and mounting graphic tracers.

Occlusion Rim (Wax Rim) Dimensions (Maxillary)

22 mm high from the depth of the sulcus at the canine eminence.
16 mm high at the posterior region from sulcus.
Anterior portion lablelly oriented and positioned.
Posterior border to anterior maxillary tuberosity.
4–6 mm wide in the anterior region
8–12 mm wide in the posterior region

Occlusion Rim (Wax Rim) Dimensions (Mandibular)

8–12 mm wide in the posterior region
4–6 mm wide in the anterior region
Posterior wax rim height is 2/3 of retromolar pad.
Maxillary rim slightly positioned forward from the ridge to compensate for ridge resorption

Marking the Occlusion Rims

High lip line
Smile line
Corners of lips
Central line or midline: below the center of philtrum
Canines lines.

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Description

Explore the essential concepts of record blocks utilized in prosthodontics for maxillomandibular relationships. This quiz covers the types, purposes, and material requirements of temporary and permanent record bases in denture construction. Test your knowledge on the importance of accuracy and stability in the recording process.