AGD Fixed and Removable Prosthodontics 5 — Questions and Answers
Question 1: During removable partial denture (RPD) insertion, a patient experiences discomfort under the denture base but not at the rest seats. What is the most likely cause?
- Overextended or overcontoured denture base impinging on soft tissue (Correct answer)
- Incorrect clasp design
- Insufficient retention
- Lack of indirect retainers
Correct answer: Overextended or overcontoured denture base impinging on soft tissue
Localized soreness under the base without rest-seat pain indicates the acrylic base is overextended or has pressure spots, which must be identified with pressure-indicating paste and relieved.
Question 2: Which registration material is preferred for recording maxillomandibular relationships in patients with reduced interocclusal space?
- Hard baseplate wax
- Vinyl polysiloxane (VPS) bite registration material (Correct answer)
- Zinc oxide eugenol impression paste
- Irreversible hydrocolloid
Correct answer: Vinyl polysiloxane (VPS) bite registration material
VPS bite registration materials set quickly, have minimal flow, and produce thin, accurate records even in patients with very limited interocclusal space.
Question 3: A 3-unit fixed partial denture replacing the maxillary first premolar uses canine and second premolar as abutments. Which pontic design is most esthetic and hygienic for this site?
- Sanitary (hygienic) pontic
- Conical pontic
- Modified ridge-lap pontic (Correct answer)
- Saddle (full ridge-lap) pontic
Correct answer: Modified ridge-lap pontic
The modified ridge-lap pontic contacts the labial/buccal ridge for esthetics while leaving the palatal/lingual surface convex and cleansable, balancing appearance and hygiene.
Question 4: Which clasp assembly component provides both retention and bracing (reciprocation) in a combination clasp on an RPD?
- Rest
- Retentive tip of the buccal clasp arm
- Reciprocal lingual arm (Correct answer)
- Minor connector
Correct answer: Reciprocal lingual arm
The reciprocal (lingual) arm is rigid and contacts the tooth above the height of contour, providing bracing against lateral forces as the retentive arm flexes over the survey line.
Question 5: In complete denture fabrication, the 'neutral zone' technique is specifically indicated for patients with:
- Adequate residual ridge height and well-defined vestibules
- Severely resorbed ridges with poor muscular control (Correct answer)
- Normal neuromuscular function and average ridge form
- Implant-retained overdentures with bar attachments
Correct answer: Severely resorbed ridges with poor muscular control
The neutral zone technique places denture teeth in the zone of minimal muscular conflict, critical when resorbed ridges provide little resistance to dislodgment by cheeks and tongue.
Question 6: A patient's existing complete denture has a loss of vertical dimension due to tooth wear. Which is the most appropriate initial prosthodontic management?
- Immediate fabrication of new complete dentures
- Relining the existing denture to restore occlusal vertical dimension
- Adding autopolymerizing acrylic to the occlusal surfaces to test the new vertical dimension (Correct answer)
- Surgical ridge augmentation before any prosthetic intervention
Correct answer: Adding autopolymerizing acrylic to the occlusal surfaces to test the new vertical dimension
Adding acrylic (or chair-side composite) to the occlusal surfaces allows evaluation of the proposed vertical dimension of occlusion before committing to new dentures.
Question 7: Which finish line preparation provides the greatest marginal strength for an all-ceramic crown compared to other margin designs?
- Knife-edge (feather) margin
- Chamfer margin
- Shoulder with bevel
- Deep chamfer (heavy chamfer) or rounded shoulder margin (Correct answer)
Correct answer: Deep chamfer (heavy chamfer) or rounded shoulder margin
A deep chamfer or rounded shoulder provides adequate bulk of ceramic material at the margin, reducing fracture risk while maintaining a definitive ledge for accurate seating.
AGD Fixed and Removable Prosthodontics 5
During removable partial denture (RPD) insertion, a patient experiences discomfort under the denture base but not at the rest seats.
What is the most likely cause?