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What is Thistle-tube appearance is a characteristic feature of: and explain in detail?
Radiographic features of type II (coronal) dentin dysplasia:
The permanent teeth exhibit an abnormally large pulp chamber in the coronal portion of the tooth, often described as ‘thistle-tube’ in shape, and within such areas radiopaque foci resembling pulp stones may be found.
Ref: Shafer's textbook of oral pathology 7th edition page 57