Lec 8 3 (hard)

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Questions and Answers

What is the primary reason for using relief wax in the fabrication of a customized tray?

To enhance the aesthetic appearance of the tray

To increase the stability of the impression material

To reduce pressure on sensitive areas of the oral cavity (correct)

To improve the adhesion of the impression tray to the oral cavity

Which anatomical structures are considered support areas during the impression process?

Tongue and floor of the mouth

Gingival tissue and soft palate

Mucosa and muscle attachment

Teeth and bone (correct)

What is the role of relief holes in a customized impression tray?

To further reduce pressure applied to specific areas (correct)

To increase the weight of the tray for better handling

To decrease the flow of impression material during setting

To provide additional anatomical landmarks for reference

How is a primary cast utilized in the fabrication of a customized impression tray?

It acts as the first duplicate from which wax relief is applied Signup and view all the answers

Which factor most influences the choice of materials for dental impressions in relation to patient comfort?

The ability of materials to compress and rebound Signup and view all the answers

Which type of mucosa is primarily found in the vestibule and cheeks of the edentulous oral cavity?

Non keratinized unattached mucosa Signup and view all the answers

What type of bone is typically found along the crest of residual ridges?

Medullary bone Signup and view all the answers

Why is thick cortical bone considered an excellent supporting structure in the oral cavity?

It resists resorption and withstands occlusal forces. Signup and view all the answers

Which factor contributes to the resistance of trauma or ulceration during denture use?

Thick keratinized attached mucosa Signup and view all the answers

Which anatomical landmark is associated with the posterior aspect of the maxilla and is relevant in denture design?

Tuberosity Signup and view all the answers

Which structure is primarily responsible for providing resistance to masticatory forces?

Pterygoid hamulus Signup and view all the answers

Which area is considered a relief area that requires relief from pressure of the denture base during function?

Crest of residual ridges Signup and view all the answers

Among the listed structures, which one is classified as a limiting structure?

Hamular notch Signup and view all the answers

Which characteristic is NOT required for a supporting structure?

Tissue should be non-attached Signup and view all the answers

What is located in the posterior palatal seal area?

Primary support Signup and view all the answers

What are the primary characteristics of supporting areas in complete dentures?

Areas that absorb occlusal forces Signup and view all the answers

Which part of the complete denture is responsible for contacting the supporting area of the mouth?

Denture base Signup and view all the answers

What is the primary role of the occlusal surface in a complete denture?

To create balance during mastication Signup and view all the answers

What happens to the forces generated during mastication in complete dentures?

They act compressively on underlying tissues Signup and view all the answers

Which of the following best describes relief areas in a denture?

Areas designed to reduce pressure on specific tissues Signup and view all the answers

What is a potential long-term consequence of the forces transmitted to supporting tissues by a complete denture?

Bone resorption in the underlying structures Signup and view all the answers

Which aspect of the denture bearing area primarily influences aesthetics?

Denture flange Signup and view all the answers

What is the definition of a denture bearing area?

Surfaces that contact the denture base Signup and view all the answers

Which anatomical landmark provides resistance to masticatory forces?

Cortical bone Signup and view all the answers

What type of mucosa is required for the areas that provide resistance?

Keratinized, attached mucosa Signup and view all the answers

Which structure is considered a limiting structure in the classification of anatomical landmarks?

Labial vestibule Signup and view all the answers

Identify an area that requires relief from pressure during denture base function.

Incisive papilla Signup and view all the answers

Which muscle is directly associated with the junction of the hard and soft palate?

Superior pharyngeal constrictor Signup and view all the answers

What does the posterior peripheral seal area define in dental anatomy?

The boundary of the denture base Signup and view all the answers

Which anatomical term is used for a connection that involves no muscle between structures?

Raphal Signup and view all the answers

Which area is NOT classified as a relief area?

Labial vestible Signup and view all the answers

Which of the following structures satisfies all three criteria for supporting structures in prosthetic applications?

Buccal shelf Signup and view all the answers

What is the primary purpose of alveoloplasty in pre-prosthetic surgeries?

Reduce sharp bony extensions of the alveolar ridge Signup and view all the answers

Which procedure is typically used to increase the depth of the sulcus around the denture?

Vestibular extension/Sulcus deepening Signup and view all the answers

What is the intended outcome of debulking flabby tissues during pre-prosthetic surgery?

To enhance mucosal support Signup and view all the answers

In which scenario would ridge augmentation be a crucial procedure?

To increase the height of the alveolar ridge Signup and view all the answers

Which treatment is performed to create vertical space in the posterior ridge without prosthetic teeth?

Tuberosity reduction Signup and view all the answers

What is the significance of the pterygo-mandibular raphe in terms of denture support?

It contributes to the stability of the denture base. Signup and view all the answers

Which statement accurately describes secondary supporting structures in denture fabrication?

They meet at least two support criteria. Signup and view all the answers

Study Notes

Prosthodontics Lecture 8 & 9 - Denture Bearing Areas

Topic: Denture bearing areas of maxilla and mandible
Lecturer: Dr. Vinothkumar Sengottaiyan (@Dr_VK)
Institution: Oman Dental College

Learning Outcomes

Differentiate denture bearing areas (supporting, relief, limiting) of maxillary and mandibular arches
Plan and condition denture bearing areas for complete dentures
Understand preprosthetic surgeries for denture construction
Identify situations needing specialist referral

Support - Definition

General: Foundation area for a dental prosthesis, resisting occlusal/functional forces
Complete dentures: Area of mouth available for support
Other: Areas in the mouth for absorbing mastication forces

Parts of Complete Denture

Denture base/foundation: Part of the denture contacting supporting areas (impression surface, intaglio surface, support areas, relief areas, and peripheral seal/border areas)
Denture flange: Surface outside denture base, called cameo/art surface, aesthetically developed by the dentist (doesn't affect function).
Occlusal surface: Formed by artificial teeth, creating balance during mastication

Denture Bearing Area

Refers to surfaces contacted by the denture base.
The denture base (fitting surface) contacts oral tissues.
Denture bases are typically made of hard materials like acrylic, and don't change shape during function.
All occlusal forces are transferred to denture bearing areas by the denture base

Forces in Complete Dentures

Forces perpendicular to the occlusal plane during mastication are transmitted to underlying supporting tissues as compressive forces.
These forces cause bone resorption in bone and ischemia (reduced blood flow) in tissues.
Bone resorption and ischemia can result in long-term problems.
However, in some instances, short-term pain, ulceration, and irritation could occur.

What Happens When We Make an Impression

A dental impression records the anatomy of the oral cavity using impression trays and appropriate materials.
Pressing the material against oral structures is compression.
The denture base applies similar force during impression making.
Some structures (teeth, bone) can withstand pressure longer; others (mucosa, muscle attachments) can't.

How to Manage Compression in Denture Bases

Fabricate a customized tray contacting only pressure-resistant areas.
Use a first duplicate (primary cast) from the preliminary impression.
Place wax sheets (relief wax) in areas needing reduced pressure during impression making.
Create a special tray with acrylic, removing the wax after the final impression.
Relief holes can further reduce pressure inside the tray.

Anatomical Landmarks

Visible/palpable structures within the oral cavity (edentulous patient).
Important for understanding how to classify structures.
Support classification helps create custom trays for selective pressure during impression making.
Support areas: Primary and secondary
Relief areas:
Border/peripheral seal areas:

Tissues of Edentulous Oral Cavity

Mucosa:
- Keratinized attached mucosa: Present on residual ridge and palate
- Non-keratinized unattached mucosa: Vestibule, cheeks, floor of mouth, soft palate, uvula, and tonsillar pillars
Submucosa: Fibrous, anterior palate, tuberosities, residual ridges
Fatty/glandular: Posterior palate, some floor of mouth areas
Muscular: Along vestibule, cheeks, floor of mouth
Bone:
- Cortical bone: Most areas except crest of residual ridges
- Medullary bone: Crest of residual ridges

Favourable Characteristics of Supporting Areas

Thick cortical bone: Avascular, resists resorption (excellent support)
Thick keratinized attached mucosa: Resists trauma/ulceration from denture movements.
Direction relative to occlusal plane: Maximum support/resistance when parallel or perpendicular to occlusal forces.

Maxillary Anatomical Landmarks

(List of specific landmarks - see the text)

Mandibular Anatomical Landmarks

(Refer to the text, list mandibular Landmarks)

Preprosthetic Surgeries

Alveoloplasty (invasive): Reduces sharp bony extensions of alveolar ridge.
Vestibular extension/Sulcus deepening: Increases sulcus depth, usually achieved with skin or mucosal grafting.
Tuberosity reduction: Creates vertical space in posterior ridge.
Debulking of flabby tissues: Achieves firm mucosal support.
Ridge augmentation: Increases height of the alveolar ridge for improved denture stability and possibly, implants instead of removable dentures.

Textbook for Reference

Zarb, G.A., 2012, Prosthodontic Treatment for Edentulous Patients: South Asia Reprint-E-book, Elsevier Health Sciences.

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Description

Dive into the intricacies of denture bearing areas in maxillary and mandibular arches with this quiz. Learn to differentiate between supporting, relief, and limiting areas, and explore the planning and conditioning of these areas for complete dentures. Understand the essentials of preprosthetic surgeries and the situations requiring specialist referrals.