CCA Implant-Retained Prosthetics 3 — Questions and Answers
Question 1: For an orbital prosthesis retained by implants, which is the typical minimum number of implants placed to provide adequate multi-point retention?
- 1
- 2
- 3 (Correct answer)
- 5
Correct answer: 3
Three implants are typically placed for orbital prostheses to distribute retention forces and provide stable multi-point attachment.
Question 2: What surface treatment on modern craniofacial titanium implants enhances osseointegration by increasing surface roughness?
- Plasma spraying with hydroxyapatite only
- Acid-etching or sandblasting (SLA surface) (Correct answer)
- Gold anodization
- Silicone coating
Correct answer: Acid-etching or sandblasting (SLA surface)
Sandblasted, large-grit, acid-etched (SLA) surfaces increase microroughness, promoting bone cell attachment and accelerating osseointegration.
Question 3: During abutment connection to an osseointegrated craniofacial implant, why is a torque-controlled wrench used?
- To prevent acoustic disturbance to the inner ear
- To avoid stripping the abutment screw and over-compressing peri-implant bone (Correct answer)
- To sterilize the connection interface
- To measure implant resonance frequency
Correct answer: To avoid stripping the abutment screw and over-compressing peri-implant bone
A calibrated torque wrench prevents abutment screw stripping and protects peri-implant bone from excessive compressive stress during tightening.
Question 4: Which imaging modality is MOST appropriate for pre-surgical assessment of bone volume and architecture at a proposed nasal implant site?
- Panoramic radiograph
- Periapical radiograph
- Cone-beam computed tomography (CBCT) (Correct answer)
- Standard lateral cephalogram
Correct answer: Cone-beam computed tomography (CBCT)
CBCT provides three-dimensional visualization of bone volume, thickness, and proximity to critical structures at craniofacial implant sites.
Question 5: A silicone auricular prosthesis retained by implants shows lateral displacement during mastication. What is the MOST likely cause?
- Implant failure
- Incorrect magnet polarity
- Insufficient number of retention points or bar rigidity (Correct answer)
- Allergic reaction to the abutment
Correct answer: Insufficient number of retention points or bar rigidity
Lateral displacement during function indicates inadequate retention stability, often due to too few implants or a flexible retention system unable to resist lateral forces.
Question 6: What is the primary purpose of a healing abutment (cover screw stage) placed immediately after craniofacial implant surgery?
- To permanently retain the prosthesis
- To protect the implant and shape the peri-implant skin during osseointegration (Correct answer)
- To measure resonance frequency analysis
- To deliver antibiotic locally
Correct answer: To protect the implant and shape the peri-implant skin during osseointegration
Healing abutments protect the implant from contamination and help condition the peri-implant skin to the correct profile during the osseointegration period.
Question 7: Radiation therapy to the head and neck prior to craniofacial implant placement is a significant risk factor primarily because it causes:
- Increased vascularity leading to excessive bleeding
- Hyperbaric oxygen dependency
- Hypovascular, hypocellular, hypoxic bone (osteoradionecrosis risk) (Correct answer)
- Accelerated osseointegration
Correct answer: Hypovascular, hypocellular, hypoxic bone (osteoradionecrosis risk)
Radiation damages the vasculature and cellular elements of bone, producing a hypoxic-hypovascular-hypocellular environment that impairs osseointegration and raises osteoradionecrosis risk.
CCA Implant-Retained Prosthetics 3
For an orbital prosthesis retained by implants, which is the typical minimum number of implants placed to provide adequate multi-point retention?