Tooth development and dental anatomy: enamel maturation enzyme: 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 maturation enzyme

Sample item

During the maturation stage of amelogenesis, the remaining enamel matrix proteins must be removed so that the crystals can thicken. Which enzyme is chiefly responsible for degrading them at this stage?

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

The answer and the reasoning

B. Kallikrein-4 (KLK4)

In the secretory stage, MMP-20 processes amelogenin and other proteins as they are laid down. In the maturation stage, KLK4 degrades the remaining proteins so that they leave the enamel and the crystals expand in width. Failure leaves soft, protein-rich enamel.

Option by option

  • A. Alkaline phosphatase

    Alkaline phosphatase is involved in mineral deposition, not in matrix protein digestion.

  • B. Kallikrein-4 (KLK4) (correct)

    Correct. KLK4 is the maturation-stage protease that clears the residual matrix.

  • C. Matrix metalloproteinase-20

    MMP-20 acts mainly in the secretory stage, on newly secreted matrix proteins.

  • D. Cathepsin K

    Cathepsin K is an osteoclast enzyme that degrades bone collagen.

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, Kallikrein-4 (KLK4). In the secretory stage, MMP-20 processes amelogenin and other proteins as they are laid down.

Why is "Alkaline phosphatase" not the answer?

Alkaline phosphatase is involved in mineral deposition, not in matrix protein digestion.

Why is "Matrix metalloproteinase-20" not the answer?

MMP-20 acts mainly in the secretory stage, on newly secreted matrix proteins.

Why is "Cathepsin K" not the answer?

Cathepsin K is an osteoclast enzyme that degrades bone collagen.

What concept does this question test?

It tests Tooth development and dental anatomy: enamel maturation enzyme in Dentistry. In the maturation stage, KLK4 degrades the remaining proteins so that they leave the enamel and the crystals expand in width. Failure leaves soft, protein-rich enamel.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. 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 maturation enzyme?

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.