CDT Implant Prosthetics Techniques 3 — Questions and Answers
Question 1: Which material is preferred for implant abutments in high esthetic zones due to its tooth-like color and biocompatibility?
- Cast gold alloy
- Cobalt-chromium alloy
- Zirconia (Y-TZP) (Correct answer)
- Commercially pure titanium (Grade 4)
Correct answer: Zirconia (Y-TZP)
Zirconia (Y-TZP) offers excellent esthetics, biocompatibility, and adequate strength for single-tooth and short-span anterior implant abutments.
Question 2: What is the function of a 'transfer impression coping' (open-tray coping) in implant prosthetics?
- It is picked up in the impression, directly capturing the implant position (Correct answer)
- It transfers the abutment shape to the laboratory
- It provides temporary occlusal support post-surgery
- It locks the abutment during final torque application
Correct answer: It is picked up in the impression, directly capturing the implant position
Open-tray transfer copings are retrieved with the impression, accurately capturing the three-dimensional position of the implant analog in the cast.
Question 3: A technician is designing an implant-retained overdenture. Which attachment system provides the greatest degree of patient-adjustable retention through clip replacement?
- Ball (O-ring) attachment
- Bar-clip attachment (Correct answer)
- Locator attachment
- Magnets
Correct answer: Bar-clip attachment
Bar-clip systems allow incremental retention adjustment by replacing the clip inserts, offering a broad range of retention levels over the prosthesis lifespan.
Question 4: In the All-on-4 treatment concept, the two posterior implants are typically placed at what angle to increase bone engagement and avoid anatomical structures?
- 15 degrees
- 30 degrees
- 45 degrees (Correct answer)
- 60 degrees
Correct answer: 45 degrees
Posterior implants in the All-on-4 concept are tilted 45 degrees to engage more bone and avoid the maxillary sinus or mandibular nerve without grafting.
Question 5: Which type of impression technique is most accurate for capturing the position of multiple implants in different axial inclinations?
- Closed-tray snap-on technique
- Open-tray splinted technique using polyether (Correct answer)
- Bite registration wax pickup
- Alginate with stock tray
Correct answer: Open-tray splinted technique using polyether
Open-tray splinted impressions with polyether minimize coping displacement and distortion, achieving the highest accuracy for multiple divergent implants.
Question 6: When cementing an implant-supported crown, excess cement below the gingival margin can cause which serious complication?
- Increased crown wear
- Peri-implant mucositis or peri-implantitis leading to bone loss (Correct answer)
- Screw channel blockage
- Loss of occlusal contacts
Correct answer: Peri-implant mucositis or peri-implantitis leading to bone loss
Subgingival cement remnants trigger an inflammatory response that can progress to peri-implant mucositis and peri-implantitis with bone loss.
Question 7: A technician is fabricating a custom abutment with a sub-gingival margin. The emergence profile should mimic which anatomical reference?
- The CEJ of a natural tooth (Correct answer)
- The opposing tooth's contour
- The ridge crest morphology
- The adjacent pontic shape
Correct answer: The CEJ of a natural tooth
The emergence profile is designed to replicate the cementoenamel junction (CEJ) contours of a natural tooth, creating an esthetic and hygienic soft-tissue interface.
CDT Implant Prosthetics Techniques 3
Which material is preferred for implant abutments in high esthetic zones due to its tooth-like color and biocompatibility?