Tooth development and dental anatomy: enamel knot: 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: enamel knot

Sample item

A research article describes a transient cluster of non-dividing epithelial cells in the enamel organ that expresses signalling molecules and directs the position of cusp tips. At which stage is this structure seen?

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

The answer and the reasoning

B. Cap stage

The primary enamel knot appears at the cap stage and acts as a signalling centre; secondary enamel knots later mark the cusp tips. Its cells undergo apoptosis once their role is done.

Option by option

  • A. Bud stage

    At the bud stage the epithelium merely proliferates into the mesenchyme and there is no cusp patterning.

  • B. Cap stage (correct)

    Correct. The enamel knot forms at the cap stage and patterns crown shape.

  • C. Eruptive stage

    Eruption occurs long after crown morphology is established.

  • D. Appositional stage

    The appositional stage is concerned with laying down matrix, after crown shape is set.

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, Cap stage. The primary enamel knot appears at the cap stage and acts as a signalling centre; secondary enamel knots later mark the cusp tips.

Why is "Bud stage" not the answer?

At the bud stage the epithelium merely proliferates into the mesenchyme and there is no cusp patterning.

Why is "Eruptive stage" not the answer?

Eruption occurs long after crown morphology is established.

Why is "Appositional stage" not the answer?

The appositional stage is concerned with laying down matrix, after crown shape is set.

What concept does this question test?

It tests Tooth development and dental anatomy: enamel knot in Dentistry. Its cells undergo apoptosis once their role is done.

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: enamel knot?

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.