CDT Implant Prosthetics Techniques 2 — Questions and Answers
Question 1: Which implant connection type uses a conical interface to create a friction-locked, cold-welded seal between the implant and abutment?
- External hex
- Internal conical (Morse taper) (Correct answer)
- Flat-to-flat butt joint
- Octagonal internal
Correct answer: Internal conical (Morse taper)
Internal conical (Morse taper) connections rely on a tapered, friction-fit interface that creates a cold-weld effect, reducing micromovement and microgap.
Question 2: When fabricating a screw-retained implant crown, the screw access channel is typically sealed with which material after final torquing?
- Amalgam
- Composite resin over PTFE tape (Correct answer)
- Zinc phosphate cement
- Glass ionomer cement
Correct answer: Composite resin over PTFE tape
PTFE (Teflon) tape is placed over the screw head followed by composite resin to allow future access while sealing the channel.
Question 3: A patient presents with a failing implant restoration where the screw repeatedly loosens. Which design modification would BEST address this?
- Switch to a wider diameter implant
- Change to a cement-retained restoration
- Increase abutment taper angle
- Use an abutment with anti-rotational features and higher torque specification (Correct answer)
Correct answer: Use an abutment with anti-rotational features and higher torque specification
Anti-rotational abutment features combined with proper torque values prevent screw loosening by distributing occlusal forces more effectively.
Question 4: In implant prosthetics, what is the primary purpose of a 'healing abutment' (also called a healing cap or cover screw)?
- To hold the final impression coping in place
- To shape the peri-implant soft tissue during osseointegration (Correct answer)
- To transfer the implant position to a master cast
- To support a provisional crown immediately after placement
Correct answer: To shape the peri-implant soft tissue during osseointegration
Healing abutments contour the gingival tissue to create the desired emergence profile before the final abutment is placed.
Question 5: Which occlusal scheme is most commonly recommended for implant-supported fixed restorations to minimize lateral forces on the implants?
- Balanced occlusion
- Canine-guided occlusion (Correct answer)
- Group function
- Lingualized occlusion
Correct answer: Canine-guided occlusion
Canine-guided occlusion discludes posterior teeth during lateral excursions, reducing harmful lateral forces transmitted to implants.
Question 6: A zirconia abutment is being fabricated for an anterior implant. Which consideration is MOST critical for long-term success?
- Ensuring the abutment is at least 5 mm in height
- Using a titanium base (Ti-base) to interface with the implant (Correct answer)
- Keeping the margin supragingival
- Avoiding any surface treatment of the zirconia
Correct answer: Using a titanium base (Ti-base) to interface with the implant
A titanium base (Ti-base) provides a reliable metal-to-metal connection at the implant interface, while the zirconia overlayer achieves esthetics without compromising strength at the critical junction.
Question 7: During the try-in of a multi-unit implant bridge, the framework does not fully seat on one implant. What is the FIRST step the technician should take?
- Sectionalize the framework and re-solder
- Check all the impression copings and verify the master cast accuracy (Correct answer)
- Grind the underseat area until it seats
- Apply pressure and take a new bite registration
Correct answer: Check all the impression copings and verify the master cast accuracy
Framework misfit most often originates from an inaccurate master cast; verifying cast accuracy and impression technique is the logical first diagnostic step.
CDT Implant Prosthetics Techniques 2
Which implant connection type uses a conical interface to create a friction-locked, cold-welded seal between the implant and abutment?