Dental Implants Bone Grafting & Ridge Augmentation 1 — Questions and Answers
Question 1: What makes autogenous bone grafts the gold standard compared to all other graft types?
- They are more readily available in large quantities
- They possess osteogenic, osteoinductive, and osteoconductive properties (Correct answer)
- They eliminate all risk of disease transmission
- They require no donor site surgery
Correct answer: They possess osteogenic, osteoinductive, and osteoconductive properties
Autogenous grafts contain living bone-forming cells (osteoblasts and osteoprogenitor cells), making them the only graft type with all three properties: osteogenic, osteoinductive, and osteoconductive.
Question 2: Which bone graft classification describes material derived from bovine or porcine bone that has been processed to remove organic components?
- Autograft
- Allograft
- Xenograft (Correct answer)
- Alloplast
Correct answer: Xenograft
Xenograft refers to bone graft material derived from a different species (e.g., bovine or porcine), which is deproteinized and deorganified to leave only the mineral scaffold for osteoconduction.
Question 3: What is the primary mechanism by which Guided Bone Regeneration (GBR) achieves bone growth?
- Delivering antibiotics directly to the surgical site
- Using barrier membranes to exclude fast-proliferating soft tissue cells (Correct answer)
- Stimulating implant surface bioactivity
- Increasing blood supply through vascular growth factors
Correct answer: Using barrier membranes to exclude fast-proliferating soft tissue cells
GBR barrier membranes physically exclude fast-proliferating epithelial and fibroblastic cells from the bone defect, creating a protected space where slower-growing osteogenic cells can regenerate bone.
Question 4: Which of the following bone graft materials is classified as an alloplast?
- Demineralized freeze-dried bone allograft (DFDBA)
- Hydroxyapatite (Correct answer)
- Bovine-derived bone mineral (Bio-Oss)
- Iliac crest cancellous autograft
Correct answer: Hydroxyapatite
Alloplasts are synthetic or inorganic bone substitutes; hydroxyapatite is a common alloplast that mimics the mineral component of natural bone and functions as an osteoconductive scaffold.
Question 5: The Schneiderian membrane must be carefully elevated and preserved during which dental implant procedure?
- Guided bone regeneration at extraction sites
- Ridge splitting for horizontal augmentation
- Maxillary sinus augmentation (Correct answer)
- Mandibular nerve transposition
Correct answer: Maxillary sinus augmentation
The Schneiderian membrane is the mucoperiosteal lining of the maxillary sinus; it must be elevated intact during sinus augmentation to create a space below the sinus floor for bone graft material without causing perforation.
Question 6: Which intraoral donor site is most commonly used to harvest cortical block bone grafts for ridge augmentation?
- Maxillary tuberosity
- Iliac crest
- Mandibular symphysis or ramus (Correct answer)
- Zygomatic arch
Correct answer: Mandibular symphysis or ramus
The mandibular symphysis (chin area) and ramus are the preferred intraoral donor sites for cortical block grafts due to their dense cortical bone quality, proximity to the surgical site, and reduced resorption compared to cancellous sources.
Question 7: Which sinus augmentation approach is preferred when residual alveolar bone height in the posterior maxilla is less than 4 mm?
- Osteotome (crestal) technique
- Lateral window (Caldwell-Luc) approach (Correct answer)
- Distraction osteogenesis
- Ridge expansion technique
Correct answer: Lateral window (Caldwell-Luc) approach
The lateral window approach is preferred when residual bone height is less than 4-5 mm because it provides direct visualization and access to safely elevate the Schneiderian membrane and place adequate graft volume; the osteotome technique requires at least 5-6 mm of native bone for implant primary stability.
Dental Implants Bone Grafting & Ridge Augmentation 1
What makes autogenous bone grafts the gold standard compared to all other graft types?