Tooth development and dental anatomy: dentine dysplasia type I: practice question

A Dentistry question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Dentistry · Tooth development and dental anatomy: dentine dysplasia type I

Sample item

A child has early loss of teeth that appear normal in colour. Radiographs show very short roots, obliterated pulp chambers and periapical radiolucencies without caries. Which disorder is most likely?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. Dentine dysplasia type I

In dentine dysplasia type I, crowns look normal but roots are short or absent, pulp chambers are obliterated, and teeth are mobile and lost early. Dentinogenesis imperfecta shows opalescent grey-brown crowns with bulbous shape and constricted cervix. The enamel is normal in dentine disorders.

Option by option

  • A. Dentinogenesis imperfecta type II

    Dentinogenesis imperfecta shows opalescent, discoloured bulbous crowns.

  • B. Dentine dysplasia type I (correct)

    Correct. Normal crowns with rootless teeth and obliterated pulps characterise type I.

  • C. Amelogenesis imperfecta

    Amelogenesis imperfecta mainly affects enamel and the roots are normal.

  • D. Regional odontodysplasia

    Regional odontodysplasia affects a segment of teeth, with a ghost-like appearance.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Dentistry question

What is the answer to this Dentistry question?

The best answer is B, Dentine dysplasia type I. In dentine dysplasia type I, crowns look normal but roots are short or absent, pulp chambers are obliterated, and teeth are mobile and lost early.

Why is "Dentinogenesis imperfecta type II" not the answer?

Dentinogenesis imperfecta shows opalescent, discoloured bulbous crowns.

Why is "Amelogenesis imperfecta" not the answer?

Amelogenesis imperfecta mainly affects enamel and the roots are normal.

Why is "Regional odontodysplasia" not the answer?

Regional odontodysplasia affects a segment of teeth, with a ghost-like appearance.

What concept does this question test?

It tests Tooth development and dental anatomy: dentine dysplasia type I in Dentistry. Dentinogenesis imperfecta shows opalescent grey-brown crowns with bulbous shape and constricted cervix. The enamel is normal in dentine disorders.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Tooth development and dental anatomy: dentine dysplasia type I?

Learn the dental formula, eruption ages and tooth structure once, as tables. Then use the flashcards and the other Dentistry questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.