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Replacement Resorption — NDEB AFK MCQ

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HardEndodonticsReplacement ResorptionNDEB AFK

Which type of resorption is characterised by replacement of root structure with bone, resulting in a characteristic ankylotic sound on percussion?

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Correct answer: E — Replacement resorption (ankylosis)

Replacement resorption occurs when the root surface is resorbed by osteoclasts and replaced by bone, fusing the tooth to the alveolar bone (ankylosis). It typically follows replantation of avulsed teeth with extensive PDL damage (e.g., dry storage >60 minutes). Clinically, the tooth produces a high-pitched metallic sound on percussion (ankylotic sound), has no mobility, is in infraocclusion (in growing patients), and shows progressive loss of root structure on radiograph.

Reference: Torabinejad – Endodontics: Principles and Practice, 6th ed., 2021; IADT Guidelines, 2020