Oral Surgery · single question
What bone formation mechanism occurs at the midpalatal suture during rapid palatal expansion in a child?
Show answer and explanation
Correct answer: B. Intramembranous ossification
The palate is a membranous bone — it forms and regenerates via intramembranous ossification (direct osteoblastic bone formation without a cartilage intermediate). During rapid palatal expansion, the sutural fibrous tissue is stretched and new bone fills in the gap via intramembranous ossification as the two palatal halves separate.
- A. ❌ Endochondral ossification involves a cartilage model — occurs in long bones and synchondroses, not flat facial bones.
- B. ✅ Intramembranous ossification — all craniofacial flat bones form this way; no cartilage intermediate.
- C. ❌ Appositional bone growth is general surface addition — not the specific mechanism for suture gap healing.
- D. ❌ Reactive bone describes repair after injury — not the specific mechanism of sutural bone formation.