CIT Bone Grafting & Osseointegration Flashcards

Which property of beta-tricalcium phosphate (β-TCP) makes it preferable to hydroxyapatite (HA) in certain ridge augmentation cases?

Answer: Faster resorption rate allowing replacement by native bone

β-TCP resorbs more rapidly than HA, creating space that is replaced by the patient's own bone, which is beneficial in sites where full bone substitution is desired.

The 'critical size defect' concept in bone grafting refers to which of the following?

Answer: The smallest defect that will not heal spontaneously without intervention

A critical size defect is defined as the smallest osseous defect that will not heal completely without augmentation during the lifetime of the animal or patient.

During second-stage implant uncovery, the clinician observes fibrous encapsulation around the implant rather than bone. This outcome is most consistent with which primary failure cause?

Answer: Micromotion exceeding 100–150 µm during the healing phase

Excessive micromotion during healing causes fibrous tissue formation rather than direct bone apposition, classically resulting in fibrous encapsulation.

Which of the following best describes the role of tenting screws in GBR procedures?

Answer: They maintain space under the membrane to allow blood clot stabilization and bone fill

Tenting screws prevent membrane collapse, preserving the protected space beneath that allows undisturbed clot organization and subsequent bone formation.

A 58-year-old patient who received IV bisphosphonate therapy for metastatic cancer requires an implant. According to current guidelines, what is the most appropriate recommendation?

Answer: Implant placement is contraindicated due to high MRONJ risk

IV bisphosphonates carry a significantly higher MRONJ risk than oral forms, making implant placement generally contraindicated in these patients.

Cortical bone decortication (cortical perforation) is performed before particulate graft placement primarily to:

Answer: Allow migration of osteogenic progenitor cells and vasculature from the medullary space

Perforating the cortical plate opens access to marrow-derived stem cells and blood supply, both essential for graft vascularization and osteogenesis.

Which implant surface characteristic is most directly associated with improved osseointegration speed in poor-quality (Type IV) bone?

Answer: Increased surface roughness (Sa 1–2 µm) via sandblasting and acid-etching (SLA)

SLA surfaces with moderate roughness (Sa 1–2 µm) maximize protein adsorption and osteoblast attachment, which is especially critical in low-density Type IV bone.