Caries, pulp and periodontal disease: C-shaped canals: 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 · Caries, pulp and periodontal disease: C-shaped canals

Sample item

On a radiograph of a mandibular second molar, the roots appear fused and the canal orifice is a continuous ribbon-like arc rather than separate round openings. What is this canal anatomy?

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

The answer and the reasoning

D. C-shaped canal

C-shaped canals are common in mandibular second molars with fused roots. The canal is an irregular ribbon that is hard to clean and fill.

Option by option

  • A. Dens invaginatus

    Dens invaginatus is an infolding of enamel into the crown or root.

  • B. Taurodontism

    Taurodontism is an enlarged pulp chamber with a low floor.

  • C. Radix entomolaris

    Radix entomolaris is an extra distolingual root on a lower first molar.

  • D. C-shaped canal (correct)

    Correct. A continuous arc-shaped orifice defines a C-shaped canal.

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 D, C-shaped canal. C-shaped canals are common in mandibular second molars with fused roots.

Why is "Dens invaginatus" not the answer?

Dens invaginatus is an infolding of enamel into the crown or root.

Why is "Taurodontism" not the answer?

Taurodontism is an enlarged pulp chamber with a low floor.

Why is "Radix entomolaris" not the answer?

Radix entomolaris is an extra distolingual root on a lower first molar.

What concept does this question test?

It tests Caries, pulp and periodontal disease: C-shaped canals in Dentistry. The canal is an irregular ribbon that is hard to clean and fill.

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 Caries, pulp and periodontal disease: C-shaped canals?

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.