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Prosthodontics & Occlusion: INBDE study notes and practice questions

Prosthodontics combines the clinical steps of making dentures and crowns with the principles of occlusion. Questions often ask what went wrong at a given step or which design feature fits the situation.

934 practice questions · 44 patient cases

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Where it fits in the official INBDE blueprint

Oral Health Management (prosthetic and occlusal care). Nearest foundation knowledge area: FK 3. See the content outline for the official weights. This mapping is approximate: real items combine a clinical area with a foundation area.

What this area tests

High-yield checklist

Common traps

These notes are original study aids, not official exam content. Confirm clinical details against current guidelines.

Sample questions

1. How does the coronoid process affect the maxillary denture?

  1. It enhances the palatal seal for better retention.
  2. It limits the buccal flange extension during function.
  3. It has no significant effect on the maxillary denture.
  4. It primarily affects the mandibular denture stability.
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Correct answer: B. It limits the buccal flange extension during function.

The coronoid process plays an important role in the functional movements of the maxillary denture. During wide opening or lateral movements of the mandible, the coronoid process may come into contact with the posterior buccal flange of the maxillary denture. This limits the extension of the buccal flange in that region to avoid interference. If the buccal flange is overextended, it can cause discomfort and instability of the denture. Therefore, careful consideration is needed during the fabrication process to ensure proper function without interference.

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2. A tooth fracture extends through the crown and continues below the cementoenamel junction into the root. How is this classified?

  1. Complicated crown fracture
  2. Uncomplicated crown fracture
  3. Crown-root fracture
  4. Root fracture
Show answer and explanation

Correct answer: C. Crown-root fracture

According to the World Dental Federation (FDI) classification of traumatic dental injuries, a crown-root fracture involves fracture of both the crown (enamel and dentin) and the root (cementum and dentin), extending below the cementoenamel junction. It may be complicated (with pulp exposure) or uncomplicated (without pulp exposure). This is distinct from a pure root fracture (horizontal fracture within the root) and crown fractures that do not extend below the CEJ.

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3. What is the single most important factor to assess before beginning treatment for a complete denture patient?

  1. The patient's expectations and motivation
  2. The shade of the denture teeth
  3. The brand of impression material
  4. The patient's astrological sign
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Correct answer: A. The patient's expectations and motivation

Understanding and managing patient expectations (and prior denture experience) is the strongest predictor of denture satisfaction and must be established before treatment.Other options: Tooth shade and material selection are technical details handled later; expectations drive overall success.Key exam takeaway: Manage expectations first; unrealistic expectations are the leading cause of denture dissatisfaction.

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4. A diastema was present between anterior teeth in a patient requiring a removable partial denture (RPD). Why was the diastema closed before fabricating the RPD?

  1. Esthetics
  2. Support
  3. Retention
  4. Stability
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Correct answer: A. Esthetics

Closing a diastema in the anterior region before fabricating an RPD is primarily done for esthetic reasons. Anterior diastemas are visible and affect the smile. While support, retention, and stability are key components of RPD design, they are primarily determined by rests, clasps, and connector design, not by closing diastemas. The diastema closure improves the final appearance of the prosthesis.

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5. What is the recommended taper per wall (axial wall convergence angle) for a full-coverage crown preparation to achieve optimal retention and resistance form?

  1. 2-5 degrees per wall
  2. 10-20 degrees per wall
  3. 20-30 degrees per wall
  4. 0-1 degree (no taper)
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Correct answer: A. 2-5 degrees per wall

The recommended taper (convergence angle) per wall for crown preparation is 2-5 degrees (sometimes expressed as 6 degrees per wall in some textbooks), with a total occlusal convergence (TOC) of approximately 10-22 degrees. A smaller taper (closer to 0 degrees) maximizes retention and resistance but risks creating undercuts. The 2-5 degree per-wall taper provides adequate draft for crown seating while maintaining frictional retention. Clinically, preparations often have greater taper (10-15 degrees per wall) due to operator technique, but this reduces retention. A taper greater than 25 degrees total significantly reduces retention. Short preparations with inadequate taper require additional features (grooves, boxes) for resistance form.

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6. Ante's Law applies to which dental procedure?

  1. Removable partial denture design
  2. Implant placement
  3. Orthodontic treatment planning
  4. Fixed partial denture (FPD/bridge) design
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Correct answer: D. Fixed partial denture (FPD/bridge) design

Ante's Law: combined PDL surface area of abutment teeth must be >= PDL surface area of missing teeth. Guides FPD abutment selection. Does NOT apply to Kennedy Class III RPD (tooth-supported).

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7. What should be done in a lithium disilicate (e.max) crown preparation to prevent fracture?

  1. Divergent walls
  2. Shoulder margin
  3. Round internal angles
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Correct answer: C. Round internal angles

✓ C) Round internal angles is correct.
Sharp internal line angles concentrate stress in ceramic restorations, promoting crack propagation and fracture. Rounding all internal angles distributes stress evenly. This is critical for lithium disilicate and all ceramic crowns.
✗ Divergent walls would reduce retention. A shoulder margin is used but alone doesn't prevent fracture — rounded angles at the axio-pulpal line angle are the key factor.
  • A. Sharp margins create stress concentration — the opposite of what is needed. Rounded internal angles are required.
  • B. For lithium disilicate (e.max) preparations, ROUNDED INTERNAL LINE ANGLES are critical to prevent STRESS CONCENTRATION and ceramic fracture. Sharp internal angles create stress risers that concentrate forces and initiate crack propagation through the ceramic. Additional requirements: adequate occlusal reduction (1.5-2mm), smooth preparation without undercuts.
  • C. Divergent walls reduce crown retention and create stress concentrations at margins — NOT recommended for lithium disilicate preparations.

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8. What is the most important consideration while fabricating complete dentures?

  1. Patient satisfaction
  2. Patient preferences
  3. Esthetics
  4. Function
Show answer and explanation

Correct answer: D. Function

While all factors matter in complete denture fabrication, FUNCTION is the primary objective. Restoring the ability to chew, speak, and maintain nutrition is the foundation of complete denture therapy. Esthetics and patient satisfaction are important secondary goals, but they should not compromise functional occlusion, vertical dimension, and stability.
  • A. INCORRECT. Patient satisfaction is a clinical goal, but it is the outcome of good function and appropriate esthetics — not the primary consideration during fabrication.
  • B. INCORRECT. Patient preferences should be accommodated within clinical limits, but patient preferences cannot override the functional requirements of a well-made denture.
  • C. INCORRECT. Esthetics are important (lip support, tooth display, smile) but are secondary to restoring function. A beautiful denture that cannot be used for chewing fails its primary purpose.
  • D. CORRECT. Function — including proper occlusion, adequate vertical dimension of occlusion, stability during chewing, and maintenance of nutrition — is the most important consideration in complete denture fabrication.

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Patient cases

All Prosthodontics & Occlusion questions (934)