CIT Implant Design & Fabrication 2 — Questions and Answers
Question 1: Which implant surface treatment increases surface roughness to promote osseointegration by creating a microtopography that enhances osteoblast attachment?
- Electropolishing
- Acid etching with HCl/H2SO4 (Correct answer)
- Anodization at low voltage
- Passivation in nitric acid
Correct answer: Acid etching with HCl/H2SO4
Acid etching with HCl/H2SO4 creates a micro-rough surface topography that significantly enhances osteoblast adhesion and osseointegration.
Question 2: A tapered implant body design is primarily chosen over a parallel-walled design in which clinical scenario?
- Posterior maxilla with abundant bone
- Extraction sockets with divergent walls (Correct answer)
- Edentulous ridges with flat bone topography
- Sites requiring immediate loading with maximum stability
Correct answer: Extraction sockets with divergent walls
Tapered implants conform well to the natural shape of extraction sockets, allowing better primary stability when socket walls diverge apically.
Question 3: What is the primary function of the implant neck (collar) design in reducing crestal bone loss?
- Increasing implant length to distribute stress
- Providing a rough microgrooved surface to engage cortical bone (Correct answer)
- Widening the implant platform for better prosthetic support
- Reducing the coefficient of friction at the bone-implant interface
Correct answer: Providing a rough microgrooved surface to engage cortical bone
Microgrooved or roughened implant necks engage cortical bone and help maintain crestal bone levels by reducing stress concentrations.
Question 4: Hydroxyapatite (HA) coating on dental implants is applied primarily to:
- Increase corrosion resistance of the titanium substrate
- Accelerate early bone-to-implant contact and osseointegration (Correct answer)
- Reduce the overall cost of implant manufacturing
- Prevent bacterial colonization on the implant surface
Correct answer: Accelerate early bone-to-implant contact and osseointegration
HA coatings are bioactive and mimic natural bone mineral, accelerating early osseointegration by promoting direct bone apposition.
Question 5: In a platform-switching design, the prosthetic abutment diameter is smaller than the implant platform diameter. This configuration primarily:
- Increases the torque capacity of the abutment screw
- Shifts the microgap away from the crestal bone to reduce bone resorption (Correct answer)
- Allows for wider prosthetic crowns on narrower implants
- Increases the total occlusal surface area of the restoration
Correct answer: Shifts the microgap away from the crestal bone to reduce bone resorption
Platform switching moves the implant-abutment junction inward, repositioning biological width establishment away from crestal bone and reducing resorption.
Question 6: Which threading pattern provides the highest insertion torque and primary stability by maximizing bone compression during placement?
- V-shaped threads with low pitch
- Square threads with aggressive pitch (Correct answer)
- Buttress threads with reverse geometry
- Spiral threads with self-tapping design
Correct answer: Square threads with aggressive pitch
Square threads have a flat load-bearing surface that distributes compressive forces broadly, generating high insertion torque and excellent primary stability.
Question 7: When fabricating a custom implant abutment using CAD/CAM technology, which material offers the best combination of esthetics and mechanical strength for an anterior single-tooth restoration?
- Cast gold alloy
- Zirconia (Y-TZP) (Correct answer)
- PMMA resin
- Composite resin with fiber reinforcement
Correct answer: Zirconia (Y-TZP)
Zirconia abutments provide excellent tooth-colored esthetics while offering high flexural strength suitable for anterior restorations with acceptable esthetic demands.
CIT Implant Design & Fabrication 2
Which implant surface treatment increases surface roughness to promote osseointegration by creating a microtopography that enhances osteoblast attachment?