Lec 8 3 (medium)

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Questions and Answers

What is the purpose of using relief wax in the process of making a dental impression?

To reduce pressure on areas that cannot withstand it (correct)

To increase the pressure applied on softer tissues

To enhance the retention of the custom tray

To simplify the impression-making process

How are structures in the oral cavity classified based on their ability to withstand pressure?

Support and relief areas (correct)

Functional and non-functional areas

Primary and secondary structures

Soft and hard structures

What is the main function of a customized tray in denture impression making?

To uniformly apply pressure across all structures

To contact only the areas that can tolerate pressure (correct)

To replicate the shapes of teeth accurately

To improve the aesthetic appearance of the impression

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

To help relieve pressure during the impression process Signup and view all the answers

Which structures in the oral cavity are more likely to get compressed during a dental impression?

Mucosa and muscle attachments Signup and view all the answers

What type of mucosa is present in the vestibule and cheeks of the edentulous oral cavity?

Non keratinized unattached mucosa Signup and view all the answers

Which of the following is NOT a favorable characteristic of supporting areas for dentures?

Presence of dental enamel Signup and view all the answers

Where is medullary bone primarily located in the edentulous oral cavity?

Crest of residual ridges Signup and view all the answers

Which tissue is absent in the mid palatine raphe of the edentulous oral cavity?

Submucosa Signup and view all the answers

What anatomical feature is found on the posterior palate of the edentulous oral cavity?

Fatty/glandular submucosa Signup and view all the answers

What is the primary function of support areas in complete dentures?

To absorb functional forces during mastication Signup and view all the answers

Which part of the complete denture closely contacts the supporting tissues?

Denture base Signup and view all the answers

What occurs when forces from complete dentures are transmitted to the bone?

Bone resorption Signup and view all the answers

What is the definition of the denture bearing area?

All surfaces that come into contact with the denture base Signup and view all the answers

What is a potential consequence of excessive occlusal forces on the denture?

Ischemia in the supporting tissues Signup and view all the answers

Which of the following is a component that does NOT influence the function of a denture?

Denture flange Signup and view all the answers

What kind of areas are relief areas within the denture bearing surface?

Regions that prevent discomfort from pressure Signup and view all the answers

When making an impression for complete dentures, what must be ensured?

The impression accurately captures the denture bearing areas Signup and view all the answers

Which area primarily serves as a support structure for a denture base?

Crest of the alveolar ridge Signup and view all the answers

Which of the following is a limiting structure in denture base extension?

Labial vestibule Signup and view all the answers

What does the term 'relief areas' refer to in the context of denture fitting?

Areas that require relief from pressure of the denture base Signup and view all the answers

What characteristic is essential for bony structures to provide adequate support for dentures?

Bone should be cortical Signup and view all the answers

Which area is considered secondary support for a denture base?

Anterior 1/3rd of palate Signup and view all the answers

Which of the following is considered a supporting structure in the classification of anatomical landmarks of the maxilla?

Cortical bone Signup and view all the answers

What type of mucosa is required for adequate denture support?

Keratinized, attached mucosa Signup and view all the answers

Which of the following areas requires relief from pressure during the function of a denture?

Canine eminence Signup and view all the answers

Which structure serves as a limiting structure for the extension of the denture base?

Buccal frenum Signup and view all the answers

What is the role of the mid palatine raphe in denture support?

Limits the extent of the denture base Signup and view all the answers

Which of the following conflicts with the required characteristics for denture-supporting structures?

Non-attached mucosa Signup and view all the answers

Which muscle is associated with the posterior peripheral seal area?

Superior pharyngeal constrictor muscle Signup and view all the answers

Which of the following accurately describes the relevance of the incisive papilla in denture fitting?

It requires relief from pressure Signup and view all the answers

Which procedure is specifically designed to enhance the depth of the sulcus in the oral cavity?

Vestibular extension/Sulcus deepening Signup and view all the answers

What is the primary purpose of ridge augmentation in dental procedures?

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

Which of the following structures can be supported by primary supporting structures when making dentures?

Buccal vestibule Signup and view all the answers

When reducing the mobility of soft tissue during denture fitting, which procedure is performed?

Debulking of flabby tissues Signup and view all the answers

In the context of pre-prosthetic surgeries, which procedure is considered the most invasive?

Alveoloplasty Signup and view all the answers

Which anatomical feature is involved in connecting structures during denture procedures?

Pterygo-mandibular raphe Signup and view all the answers

What is the aim of tuberosity reduction in the context of denture making?

To accommodate posterior denture base extension Signup and view all the answers

Which of the following lists the criteria for primary supporting structures?

Satisfies all 3 criteria Signup and view all the answers

Study Notes

Prosthodontics Lecture 8 & 9 - Denture Bearing Areas

Module: Prosthodontics 3 (BDS IV/Semester 7)
Lecturer: Dr Vinothkumar Sengottaiyan (@Dr_VK)
Institution: Oman Dental College

Learning Outcomes

Differentiate denture bearing areas of maxillary and mandibular arches into supporting, relief, and limiting areas.
Plan and condition denture bearing areas for complete dentures.
Understand possible preprosthetic surgeries for denture construction.
Identify situations requiring specialist referral for further management.

Support - Definition

General: Foundation area for a dental prosthesis.
Also refers to resistance that a prosthesis can have against occlusal/functional forces.
In complete dentures: Area of the mouth available for support.
Supporting areas in the mouth are best suited for absorbing functional forces during mastication.

Parts of Complete Denture

Denture Base/Foundation: Part of the denture that contacts the supporting area (denture bearing area).
Also called impression surface or intaglio surface.
Recorded and reproduced by final impression.
- Subdivisions: Support areas, relief areas, and peripheral seal/border areas.
Denture Flange: Surface outside the denture base.
- Also called cameo/art surface.
- Developed by the dentist – influences aesthetics, not function.
Occlusal Surface: Surface formed by artificial teeth.
- Used for creating balance for dentures during mastication.

Denture Bearing Area

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

Forces in Complete Dentures

Forces perpendicular to the occlusal plane are generated in complete dentures during mastication.
These forces are transmitted as compressive forces to the underlying supporting tissues.
In bone, these forces cause bone resorption.
In tissues, these forces cause ischemia (reduction of blood flow).
Bone resorption and ischemia are long-term problems.
However, some pain, ulceration, and irritation can occur instantly or in short-term use.

What Happens When We Make an Impression?

A dental impression records the anatomy of the oral cavity using impression trays and appropriate materials.
Pressing materials against structures in the oral cavity is compression.
Denture base applies similar force for making an impression.
Some structures (teeth, bone) withstand pressure, others (mucosa, muscles) are compressed.

How to Manage Compression in Denture Bases?

Fabricate a customized tray contacting only pressure-resistant areas.
Fabricate the tray with a primary cast from an initial/preliminary impression.
Implement wax sheets (called relief wax) in areas needing pressure reduction.
Fabricate a special tray with acrylic.
Remove wax before the final impression.
Use relief holes in the tray to further reduce pressure.

Anatomical Landmarks

Visible/palpable structures in the edentulous oral cavity.
Important for impressions and casts.
Knowledge of classification is essential for making custom trays for selective pressure applications during impression making.
- Support areas (primary and secondary).
- Relief areas.
- Border areas/peripheral seal areas.

Tissues of Edentulous Oral Cavity

Mucosa:
- Keratinized attached mucosa (residual ridge and palate).
- Non-keratinized unattached mucosa (vestibule, cheeks, floor of mouth, soft palate, uvula, tonsillar pillars).
Submucosa: Fibrous tissue (anterior palate, tuberosities, residual ridges).
Fatty/glandular tissue: (posterior palate, some areas of floor of mouth).
Muscular tissue: (along vestibule, cheek, floor of mouth).
Bone:
- Cortical bone (most areas except crest of residual ridges).
- Medullary bone (along crest of residual ridges).

Favourable Characteristics of Supporting Areas

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

Maxillary Anatomical Landmarks

Detailed list of landmarks (e.g. Tuberosity, Buccal frenum, Crest of residual ridge).

Mandible Anatomical Landmarks (Self-Assessment)

Detailed list of landmarks (Refer to the next slide and label the picture).

Classification of Anatomical Landmarks - Mandible

Supporting Structures: (provide resistance to masticatory forces), specific characteristics like cortical bone, keratinized mucosa, perpendicular to occlusal forces. Categorized into primary and secondary, including the buccal shelf and slopes of residual ridge.
Limiting Structures: (limit denture base extension), including labial frenum, labial/buccal vestibule, pterygo-mandibular raphe, lingual frenum, and lingual vestibule.
Relief Areas: (require relief from denture base pressure during function), including areas like mental foramen, crest of residual ridges, canine and premolar eminences, genial tubercles, and mylohyoid ridges..

Pre-Prosthetic Surgeries

Alveoloplasty: Reduce sharp bony extensions of the alveolar ridge.
Vestibular Extension/Sulcus Deepening: Increase sulcus depth, often via skin/mucosal grafting.
Tuberosity Reduction: Create space in posterior ridge for posterior denture base extensions.
Debulking of Flabby Tissues: Achieve firm mucosal support.
Ridge Augmentation: Increase alveolar ridge height to improve denture stability. Implants may be considered, depending on the type of augmentation.

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

Explore the denture bearing areas in the maxillary and mandibular arches through this quiz based on Prosthodontics Lectures 8 and 9. You'll learn about supporting, relief, and limiting areas, alongside preprosthetic surgeries essential for complete dentures. Perfect for BDS IV students looking to enhance their understanding of denture construction.