ABP Implant Dentistry 3 — Questions and Answers
Question 1: Guided bone regeneration (GBR) membranes function primarily by:
- Delivering antibiotics to the surgical site
- Excluding non-osteogenic cells from the healing space (Correct answer)
- Stimulating osteoblast differentiation directly
- Increasing blood supply to the graft material
Correct answer: Excluding non-osteogenic cells from the healing space
GBR membranes act as physical barriers that exclude rapidly proliferating epithelial and connective tissue cells, allowing osteogenic cells to repopulate the defect.
Question 2: Which anatomical structure is most at risk during sinus floor elevation via the lateral window approach?
- Inferior alveolar nerve
- Schneiderian membrane (Correct answer)
- Greater palatine artery
- Nasopalatine nerve
Correct answer: Schneiderian membrane
The Schneiderian membrane (sinus mucosa) is the primary structure at risk during lateral sinus augmentation; perforation significantly increases complication rates.
Question 3: According to the ITI consensus, a residual bone height of at least how many millimeters allows implant placement simultaneously with osteotome sinus floor elevation?
- 3 mm
- 5 mm (Correct answer)
- 7 mm
- 9 mm
Correct answer: 5 mm
The ITI recommends a minimum residual bone height of 5 mm to achieve adequate primary stability when performing simultaneous implant placement with the osteotome technique.
Question 4: A patient develops retrograde peri-implantitis 3 months after implant placement. The most likely etiology is:
- Occlusal overload from opposing restoration
- Pre-existing periapical pathology on an adjacent tooth (Correct answer)
- Inadequate implant surface roughness
- Excess cement at the implant-abutment interface
Correct answer: Pre-existing periapical pathology on an adjacent tooth
Retrograde peri-implantitis most commonly results from contamination by periapical pathogens from a pre-existing lesion on an adjacent tooth migrating to the implant apex.
Question 5: Which of the following is the primary disadvantage of using zygomatic implants in severely atrophic maxillae?
- Insufficient implant length for stability
- Risk of orbital floor perforation
- High rate of sinus membrane perforation and sinusitis (Correct answer)
- Inability to achieve immediate loading
Correct answer: High rate of sinus membrane perforation and sinusitis
Zygomatic implants traverse the maxillary sinus and are associated with a meaningful risk of chronic sinusitis due to sinus membrane disruption.
Question 6: The biologic width around a dental implant (peri-implant supracrestal tissue attachment) differs from natural teeth primarily because:
- It lacks a junctional epithelium component
- The connective tissue fibers run parallel rather than perpendicular to the implant surface (Correct answer)
- It is significantly wider (≥5 mm) than around teeth
- It contains Sharpey fibers embedded in the implant surface
Correct answer: The connective tissue fibers run parallel rather than perpendicular to the implant surface
Peri-implant connective tissue fibers run parallel to the implant surface (circumferential) because there is no cementum for perpendicular fiber insertion, unlike natural teeth.
Question 7: When evaluating a cone beam CT prior to posterior mandibular implant placement, the minimum recommended safety margin from the inferior alveolar canal is:
- 0.5 mm
- 1.0 mm
- 2.0 mm (Correct answer)
- 3.0 mm
Correct answer: 2.0 mm
A safety margin of at least 2 mm from the inferior alveolar canal is recommended to minimize the risk of neurosensory disturbance during implant placement.
ABP Implant Dentistry 3
Guided bone regeneration (GBR) membranes function primarily by: