Tooth development: Hertwig's root sheath: 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: Hertwig's root sheath

Sample item

During tooth development, which structure induces odontoblast differentiation in the root and moulds the number and shape of the roots?

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

The answer and the reasoning

B. Hertwig's epithelial root sheath

Hertwig's sheath grows from the cervical loop of the enamel organ and induces radicular dentin formation. Its folding determines whether a tooth has one root or several. The sheath then breaks up, allowing follicle cells to reach the dentin and form cementum.

Option by option

  • A. Stellate reticulum

    Stellate reticulum cushions the enamel organ and disappears as enamel forms.

  • B. Hertwig's epithelial root sheath (correct)

    Correct. The sheath induces root dentin and shapes the roots.

  • C. Dental follicle

    The dental follicle forms cementum, periodontal ligament and alveolar bone but does not mould root form.

  • D. Reduced enamel epithelium

    Reduced enamel epithelium covers the finished crown enamel and forms the junctional epithelium; it does not shape roots.

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, Hertwig's epithelial root sheath. Hertwig's sheath grows from the cervical loop of the enamel organ and induces radicular dentin formation.

Why is "Stellate reticulum" not the answer?

Stellate reticulum cushions the enamel organ and disappears as enamel forms.

Why is "Dental follicle" not the answer?

The dental follicle forms cementum, periodontal ligament and alveolar bone but does not mould root form.

Why is "Reduced enamel epithelium" not the answer?

Reduced enamel epithelium covers the finished crown enamel and forms the junctional epithelium; it does not shape roots.

What concept does this question test?

It tests Tooth development: Hertwig's root sheath in Dentistry. Its folding determines whether a tooth has one root or several. The sheath then breaks up, allowing follicle cells to reach the dentin and form cementum.

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: Hertwig's root sheath?

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.